Migrated to Android Studio/gradle

* moved all dependencies to gradle instead of shipping .jar files in the app/lib directory
* switched to official Android port of HttpClient instead of httpclientandroidlib
* new .gitignore and project files

.gitignore

@@ -0,0 +1,86 @@
+# Created by https://www.gitignore.io
+
+### Android ###
+# Built application files
+*.apk
+*.ap_
+
+# Files for the Dalvik VM
+*.dex
+
+# Java class files
+*.class
+
+# Generated files
+bin/
+gen/
+
+# Gradle files
+.gradle/
+build/
+
+# Local configuration file (sdk path, etc)
+local.properties
+
+# Proguard folder generated by Eclipse
+proguard/
+
+# Log Files
+*.log
+
+
+### Intellij ###
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm
+
+*.iml
+
+## Directory-based project format:
+.idea/
+# if you remove the above rule, at least ignore the following:
+
+# User-specific stuff:
+# .idea/workspace.xml
+# .idea/tasks.xml
+# .idea/dictionaries
+
+# Sensitive or high-churn files:
+# .idea/dataSources.ids
+# .idea/dataSources.xml
+# .idea/sqlDataSources.xml
+# .idea/dynamic.xml
+# .idea/uiDesigner.xml
+
+# Gradle:
+# .idea/gradle.xml
+# .idea/libraries
+
+# Mongo Explorer plugin:
+# .idea/mongoSettings.xml
+
+## File-based project format:
+*.ipr
+*.iws
+
+## Plugin-specific files:
+
+# IntelliJ
+out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+
+
+### Gradle ###
+.gradle
+build/
+
+# Ignore Gradle GUI config
+gradle-app.setting

app/.gitignore

@@ -0,0 +1 @@
+build

app/build.gradle

@@ -0,0 +1,62 @@
+apply plugin: 'com.android.application'
+
+android {
+    compileSdkVersion 21
+    buildToolsVersion "21.1.2"
+
+    defaultConfig {
+        applicationId "at.bitfire.davdroid"
+        minSdkVersion 14
+        targetSdkVersion 21
+
+        testApplicationId "at.bitfire.davdroid.test"
+        testInstrumentationRunner "android.test.InstrumentationTestRunner"
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled true
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
+        }
+    }
+    dexOptions {
+    }
+
+    packagingOptions {
+        exclude 'META-INF/LICENSE.txt'
+        exclude 'META-INF/NOTICE.txt'
+    }
+}
+
+dependencies {
+    // Apache Commons
+    compile 'commons-lang:commons-lang:2.6'
+    compile 'org.apache.commons:commons-io:1.3.2'
+
+    // Lombok for useful @helpers
+    compile 'org.projectlombok:lombok:1.14.8'
+
+    // ical4j for parsing/generating iCalendars
+    compile 'org.mnode.ical4j:ical4j:1.0.6'
+
+    // ez-vcard for parsing/generating VCards
+    compile('com.googlecode.ez-vcard:ez-vcard:0.9.6') {
+        // hCard functionality not needed
+        exclude group: 'org.jsoup', module: 'jsoup'
+        exclude group: 'org.freemarker', module: 'freemarker'
+        // jCard functionality not needed
+        exclude group: 'com.fasterxml.jackson.core', module: 'jackson-core'
+    }
+
+    // dnsjava for querying SRV/TXT records
+    compile 'dnsjava:dnsjava:2.1.6'
+
+    // HttpClient 4.3, Android flavour for WebDAV operations
+    compile 'org.apache.httpcomponents:httpclient-android:4.3.5'
+
+    // SimpleXML for parsing and generating WebDAV messages
+    compile('org.simpleframework:simple-xml:2.7.1') {
+        exclude group: 'stax', module: 'stax-api'
+        exclude group: 'xpp3', module: 'xpp3'
+    }
+}

app/lint.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<lint>
+    <issue id="ExtraTranslation" severity="warning" />
+    <issue id="MissingTranslation" severity="warning" />
+</lint>

app/src/androidTest/java/at/bitfire/davdroid/resource/test/ContactTest.java

@@ -0,0 +1,65 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.resource.test;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import ezvcard.property.Email;
+import ezvcard.property.Telephone;
+import lombok.Cleanup;
+import android.content.res.AssetManager;
+import android.test.InstrumentationTestCase;
+import at.bitfire.davdroid.resource.Contact;
+import at.bitfire.davdroid.resource.InvalidResourceException;
+
+public class ContactTest extends InstrumentationTestCase {
+	AssetManager assetMgr;
+	
+	public void setUp() throws IOException, InvalidResourceException {
+		assetMgr = getInstrumentation().getContext().getResources().getAssets();
+	}
+	
+	public void testReferenceVCard() throws IOException, InvalidResourceException {
+		Contact c = parseVCF("reference.vcf");
+		assertEquals("Gump", c.getFamilyName());
+		assertEquals("Forrest", c.getGivenName());
+		assertEquals("Forrest Gump", c.getDisplayName());
+		assertEquals("Bubba Gump Shrimp Co.", c.getOrganization().getValues().get(0));
+		assertEquals("Shrimp Man", c.getJobTitle());
+		
+		Telephone phone1 = c.getPhoneNumbers().get(0);
+		assertEquals("(111) 555-1212", phone1.getText());
+		assertEquals("WORK", phone1.getParameters("TYPE").get(0));
+		assertEquals("VOICE", phone1.getParameters("TYPE").get(1));
+		
+		Telephone phone2 = c.getPhoneNumbers().get(1);
+		assertEquals("(404) 555-1212", phone2.getText());
+		assertEquals("HOME", phone2.getParameters("TYPE").get(0));
+		assertEquals("VOICE", phone2.getParameters("TYPE").get(1));
+		
+		Email email = c.getEmails().get(0);
+		assertEquals("forrestgump@example.com", email.getValue());
+		assertEquals("PREF", email.getParameters("TYPE").get(0));
+		assertEquals("INTERNET", email.getParameters("TYPE").get(1));
+	}
+	
+	public void testParseInvalidUnknownProperties() throws IOException, InvalidResourceException {
+		Contact c = parseVCF("invalid-unknown-properties.vcf");
+		assertEquals("VCard with invalid unknown properties", c.getDisplayName());
+		assertNull(c.getUnknownProperties());
+	}
+	
+	
+	protected Contact parseVCF(String fname) throws IOException, InvalidResourceException {
+		@Cleanup InputStream in = assetMgr.open(fname, AssetManager.ACCESS_STREAMING);
+		Contact c = new Contact(fname, null);
+		c.parseEntity(in);
+		return c;
+	}
+}

app/src/androidTest/java/at/bitfire/davdroid/resource/test/EventTest.java

@@ -0,0 +1,127 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.resource.test;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import lombok.Cleanup;
+import net.fortuna.ical4j.data.ParserException;
+import android.content.res.AssetManager;
+import android.test.InstrumentationTestCase;
+import android.text.format.Time;
+import at.bitfire.davdroid.resource.Event;
+import at.bitfire.davdroid.resource.InvalidResourceException;
+
+public class EventTest extends InstrumentationTestCase {
+	AssetManager assetMgr;
+	
+	Event	eViennaEvolution,
+			eOnThatDay, eAllDay1Day, eAllDay10Days, eAllDay0Sec;
+	
+	public void setUp() throws IOException, InvalidResourceException {
+		assetMgr = getInstrumentation().getContext().getResources().getAssets();
+		
+		eViennaEvolution = parseCalendar("vienna-evolution.ics");
+		eOnThatDay = parseCalendar("event-on-that-day.ics");
+		eAllDay1Day = parseCalendar("all-day-1day.ics");
+		eAllDay10Days = parseCalendar("all-day-10days.ics");
+		eAllDay0Sec = parseCalendar("all-day-0sec.ics");
+		
+		//assertEquals("Test-Ereignis im schönen Wien", e.getSummary());
+	}
+	
+	
+	public void testStartEndTimes() throws IOException, ParserException {
+		// event with start+end date-time
+		assertEquals(1381330800000L, eViennaEvolution.getDtStartInMillis());
+		assertEquals("Europe/Vienna", eViennaEvolution.getDtStartTzID());
+		assertEquals(1381334400000L, eViennaEvolution.getDtEndInMillis());
+		assertEquals("Europe/Vienna", eViennaEvolution.getDtEndTzID());
+	}
+	
+	public void testStartEndTimesAllDay() throws IOException, ParserException {
+		// event with start date only
+		assertEquals(868838400000L, eOnThatDay.getDtStartInMillis());
+		assertEquals(Time.TIMEZONE_UTC, eOnThatDay.getDtStartTzID());
+		// DTEND missing in VEVENT, must have been set to DTSTART+1 day
+		assertEquals(868838400000L + 86400000, eOnThatDay.getDtEndInMillis());
+		assertEquals(Time.TIMEZONE_UTC, eOnThatDay.getDtEndTzID());
+		
+		// event with start+end date for all-day event (one day)
+		assertEquals(868838400000L, eAllDay1Day.getDtStartInMillis());
+		assertEquals(Time.TIMEZONE_UTC, eAllDay1Day.getDtStartTzID());
+		assertEquals(868838400000L + 86400000, eAllDay1Day.getDtEndInMillis());
+		assertEquals(Time.TIMEZONE_UTC, eAllDay1Day.getDtEndTzID());
+		
+		// event with start+end date for all-day event (ten days)
+		assertEquals(868838400000L, eAllDay10Days.getDtStartInMillis());
+		assertEquals(Time.TIMEZONE_UTC, eAllDay10Days.getDtStartTzID());
+		assertEquals(868838400000L + 10*86400000, eAllDay10Days.getDtEndInMillis());
+		assertEquals(Time.TIMEZONE_UTC, eAllDay10Days.getDtEndTzID());
+		
+		// event with start+end date on some day (invalid 0 sec-event)
+		assertEquals(868838400000L, eAllDay0Sec.getDtStartInMillis());
+		assertEquals(Time.TIMEZONE_UTC, eAllDay0Sec.getDtStartTzID());
+		// DTEND invalid in VEVENT, must have been set to DTSTART+1 day
+		assertEquals(868838400000L + 86400000, eAllDay0Sec.getDtEndInMillis());
+		assertEquals(Time.TIMEZONE_UTC, eAllDay0Sec.getDtEndTzID());
+	}
+	
+	public void testTimezoneDefToTzId() {
+		// test valid definition
+		final String VTIMEZONE_SAMPLE =		// taken from RFC 4791, 5.2.2. CALDAV:calendar-timezone Property 
+				"BEGIN:VCALENDAR\n" + 
+				"PRODID:-//Example Corp.//CalDAV Client//EN\n" + 
+				"VERSION:2.0\n" + 
+				"BEGIN:VTIMEZONE\n" + 
+				"TZID:US-Eastern\n" + 
+				"LAST-MODIFIED:19870101T000000Z\n" + 
+				"BEGIN:STANDARD\n" + 
+				"DTSTART:19671029T020000\n" + 
+				"RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10\n" + 
+				"TZOFFSETFROM:-0400\n" + 
+				"TZOFFSETTO:-0500\n" + 
+				"TZNAME:Eastern Standard Time (US & Canada)\n" + 
+				"END:STANDARD\n" + 
+				"BEGIN:DAYLIGHT\n" + 
+				"DTSTART:19870405T020000\n" + 
+				"RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4\n" + 
+				"TZOFFSETFROM:-0500\n" + 
+				"TZOFFSETTO:-0400\n" + 
+				"TZNAME:Eastern Daylight Time (US & Canada)\n" + 
+				"END:DAYLIGHT\n" + 
+				"END:VTIMEZONE\n" + 
+				"END:VCALENDAR";
+		assertEquals("US-Eastern", Event.TimezoneDefToTzId(VTIMEZONE_SAMPLE));
+
+		// test null value
+		try {
+			Event.TimezoneDefToTzId(null);
+			fail();
+		} catch(IllegalArgumentException e) {
+			assert(true);
+		}
+		
+		// test invalid time zone
+		try {
+			Event.TimezoneDefToTzId("/* invalid content */");
+			fail();
+		} catch(IllegalArgumentException e) {
+			assert(true);
+		}
+	}
+	
+	
+	protected Event parseCalendar(String fname) throws IOException, InvalidResourceException {
+		@Cleanup InputStream in = assetMgr.open(fname, AssetManager.ACCESS_STREAMING);
+		Event e = new Event(fname, null);
+		e.parseEntity(in);
+		return e;
+	}
+}

app/src/androidTest/java/at/bitfire/davdroid/resource/test/LocalCalendarTest.java

@@ -0,0 +1,154 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.resource.test;
+
+import java.util.Calendar;
+
+import lombok.Cleanup;
+import android.accounts.Account;
+import android.annotation.TargetApi;
+import android.content.ContentProviderClient;
+import android.content.ContentResolver;
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.database.Cursor;
+import android.net.Uri;
+import android.os.Build;
+import android.os.RemoteException;
+import android.provider.CalendarContract;
+import android.provider.CalendarContract.Attendees;
+import android.provider.CalendarContract.Calendars;
+import android.provider.CalendarContract.Events;
+import android.provider.CalendarContract.Reminders;
+import android.test.InstrumentationTestCase;
+import android.util.Log;
+import at.bitfire.davdroid.resource.LocalCalendar;
+import at.bitfire.davdroid.resource.LocalStorageException;
+
+public class LocalCalendarTest extends InstrumentationTestCase {
+	
+	private static final String
+		TAG = "davroid.LocalCalendarTest",
+		calendarName = "DAVdroid_Test";
+	
+	ContentProviderClient providerClient;
+	Account testAccount = new Account(calendarName, CalendarContract.ACCOUNT_TYPE_LOCAL);
+	LocalCalendar testCalendar;
+	
+	
+	// helpers
+	
+	private Uri syncAdapterURI(Uri uri) {
+		return uri.buildUpon()
+				.appendQueryParameter(Calendars.ACCOUNT_NAME, calendarName)
+				.appendQueryParameter(Calendars.ACCOUNT_TYPE, CalendarContract.ACCOUNT_TYPE_LOCAL)
+				.appendQueryParameter(CalendarContract.CALLER_IS_SYNCADAPTER, "true").
+				build();
+	}
+	
+	private long insertNewEvent() throws LocalStorageException, RemoteException {
+		ContentValues values = new ContentValues();
+		values.put(Events.CALENDAR_ID, testCalendar.getId());
+		values.put(Events.TITLE, "Test Event");
+		values.put(Events.ALL_DAY, 0);
+		values.put(Events.DTSTART, Calendar.getInstance().getTimeInMillis());
+		values.put(Events.DTEND, Calendar.getInstance().getTimeInMillis());
+		values.put(Events.EVENT_TIMEZONE, "UTC");
+		values.put(Events.DIRTY, 1);
+		return ContentUris.parseId(providerClient.insert(syncAdapterURI(Events.CONTENT_URI), values));
+	}
+	
+	private void deleteEvent(long id) throws RemoteException {
+		providerClient.delete(syncAdapterURI(ContentUris.withAppendedId(Events.CONTENT_URI, id)), null, null);
+	}
+	
+	
+	// initialization
+	
+	@TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1)
+	protected void setUp() throws Exception {
+		ContentResolver resolver = getInstrumentation().getContext().getContentResolver();
+		providerClient = resolver.acquireContentProviderClient(CalendarContract.AUTHORITY);
+		
+		long id;
+		
+		@Cleanup Cursor cursor = providerClient.query(Calendars.CONTENT_URI,
+				new String[] { Calendars._ID },
+				Calendars.ACCOUNT_TYPE + "=? AND " + Calendars.NAME + "=?",
+				new String[] { CalendarContract.ACCOUNT_TYPE_LOCAL, calendarName },
+				null);
+		if (cursor.moveToNext()) {
+			// found local test calendar
+			id = cursor.getLong(0);
+			Log.d(TAG, "Found test calendar with ID " + id);
+			
+		} else {
+			// no local test calendar found, create 
+			ContentValues values = new ContentValues();
+			values.put(Calendars.ACCOUNT_NAME, testAccount.name);
+			values.put(Calendars.ACCOUNT_TYPE, testAccount.type);
+			values.put(Calendars.NAME, calendarName);
+			values.put(Calendars.CALENDAR_DISPLAY_NAME, calendarName);
+			values.put(Calendars.CALENDAR_ACCESS_LEVEL, Calendars.CAL_ACCESS_OWNER);
+			values.put(Calendars.ALLOWED_REMINDERS, Reminders.METHOD_ALERT);
+			values.put(Calendars.SYNC_EVENTS, 0);
+			values.put(Calendars.VISIBLE, 1);
+			
+			if (android.os.Build.VERSION.SDK_INT >= 15) {
+				values.put(Calendars.ALLOWED_AVAILABILITY, Events.AVAILABILITY_BUSY + "," + Events.AVAILABILITY_FREE + "," + Events.AVAILABILITY_TENTATIVE);
+				values.put(Calendars.ALLOWED_ATTENDEE_TYPES, Attendees.TYPE_NONE + "," + Attendees.TYPE_OPTIONAL + "," + Attendees.TYPE_REQUIRED + "," + Attendees.TYPE_RESOURCE);
+			}
+			
+			Uri calendarURI = providerClient.insert(syncAdapterURI(Calendars.CONTENT_URI), values);
+			
+			id = ContentUris.parseId(calendarURI);
+			Log.d(TAG, "Created test calendar with ID " + id);
+		}
+		
+		testCalendar = new LocalCalendar(testAccount, providerClient, id, null);
+	}
+
+	protected void tearDown() throws Exception {
+		Uri uri = ContentUris.withAppendedId(syncAdapterURI(Calendars.CONTENT_URI), testCalendar.getId());
+		providerClient.delete(uri, null, null);
+	}
+
+	
+	// tests
+	
+	public void testCTags() throws LocalStorageException {
+		assertNull(testCalendar.getCTag());
+		
+		final String cTag = "just-modified"; 
+		testCalendar.setCTag(cTag);
+		
+		assertEquals(cTag, testCalendar.getCTag());
+	}
+	
+	public void testFindNew() throws LocalStorageException, RemoteException {
+		// at the beginning, there are no dirty events 
+		assertTrue(testCalendar.findNew().length == 0);
+		assertTrue(testCalendar.findUpdated().length == 0);
+		
+		// insert a "new" event
+		long id = insertNewEvent();
+		try {
+			// there must be one "new" event now
+			assertTrue(testCalendar.findNew().length == 1);
+			assertTrue(testCalendar.findUpdated().length == 0);
+					
+			// nothing has changed, the record must still be "new"
+			// see issue #233
+			assertTrue(testCalendar.findNew().length == 1);
+			assertTrue(testCalendar.findUpdated().length == 0);
+		} finally {
+			deleteEvent(id);
+		}
+	}
+
+}

app/src/androidTest/java/at/bitfire/davdroid/syncadapter/DavResourceFinderTest.java

@@ -0,0 +1,69 @@
+package at.bitfire.davdroid.syncadapter;
+
+import java.io.IOException;
+import java.net.URI;
+import java.util.List;
+
+import android.test.InstrumentationTestCase;
+import at.bitfire.davdroid.resource.DavResourceFinder;
+import at.bitfire.davdroid.resource.ServerInfo;
+import at.bitfire.davdroid.resource.ServerInfo.ResourceInfo;
+import at.bitfire.davdroid.test.Constants;
+import ezvcard.VCardVersion;
+
+public class DavResourceFinderTest extends InstrumentationTestCase {
+	
+	DavResourceFinder finder;
+
+	@Override
+	protected void setUp() {
+		finder = new DavResourceFinder(getInstrumentation().getContext());
+	}
+	
+	@Override
+	protected void tearDown() throws IOException {
+		finder.close();
+	}
+	
+
+	public void testFindResourcesRobohydra() throws Exception {
+		ServerInfo info = new ServerInfo(new URI(Constants.ROBOHYDRA_BASE), "test", "test", true);
+		finder.findResources(info);
+		
+		// CardDAV
+		assertTrue(info.isCardDAV());
+		List<ResourceInfo> collections = info.getAddressBooks();
+		assertEquals(1, collections.size());
+		
+		assertEquals("Default Address Book", collections.get(0).getDescription());
+		assertEquals(VCardVersion.V4_0, collections.get(0).getVCardVersion());
+		
+		// CalDAV
+		assertTrue(info.isCalDAV());
+		collections = info.getCalendars();
+		assertEquals(2, collections.size());
+		
+		ResourceInfo resource = collections.get(0);
+		assertEquals("Private Calendar", resource.getTitle());
+		assertEquals("This is my private calendar.", resource.getDescription());
+		assertFalse(resource.isReadOnly());
+		
+		resource = collections.get(1);
+		assertEquals("Work Calendar", resource.getTitle());
+		assertTrue(resource.isReadOnly());
+	}
+	
+	
+	public void testGetInitialContextURL() throws Exception {
+		// without SRV records, but with well-known paths
+		ServerInfo roboHydra = new ServerInfo(new URI(Constants.ROBOHYDRA_BASE), "test", "test", true);
+		assertEquals(Constants.roboHydra.resolve("/"), finder.getInitialContextURL(roboHydra, "caldav"));
+		assertEquals(Constants.roboHydra.resolve("/"), finder.getInitialContextURL(roboHydra, "carddav"));
+		
+		// with SRV records and well-known paths
+		ServerInfo iCloud = new ServerInfo(new URI("mailto:test@icloud.com"), "", "", true);
+		assertEquals(new URI("https://contacts.icloud.com/"), finder.getInitialContextURL(iCloud, "carddav"));
+		assertEquals(new URI("https://caldav.icloud.com/"), finder.getInitialContextURL(iCloud, "caldav"));
+	}
+
+}

app/src/androidTest/java/at/bitfire/davdroid/test/ArrayUtilsTest.java

@@ -0,0 +1,39 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.test;
+import java.util.Arrays;
+
+import junit.framework.TestCase;
+import at.bitfire.davdroid.ArrayUtils;
+
+
+public class ArrayUtilsTest extends TestCase {
+	
+	public void testPartition() {
+		// n == 0
+		assertTrue(Arrays.deepEquals(
+				new Long[0][0],
+				ArrayUtils.partition(new Long[] { }, 5)));
+				
+		// n < max
+		assertTrue(Arrays.deepEquals(
+				new Long[][] { { 1l, 2l } },
+				ArrayUtils.partition(new Long[] { 1l, 2l }, 5)));
+		
+		// n == max
+		assertTrue(Arrays.deepEquals(
+				new Long[][] { { 1l, 2l }, { 3l, 4l } },
+				ArrayUtils.partition(new Long[] { 1l, 2l, 3l, 4l }, 2)));
+		
+		// n > max
+		assertTrue(Arrays.deepEquals(
+				new Long[][] { { 1l, 2l, 3l, 4l, 5l }, { 6l, 7l, 8l, 9l, 10l }, { 11l } },
+				ArrayUtils.partition(new Long[] { 1l, 2l, 3l, 4l, 5l, 6l, 7l, 8l, 9l, 10l, 11l }, 5)));
+	}
+	
+}

app/src/androidTest/java/at/bitfire/davdroid/test/Constants.java

@@ -0,0 +1,19 @@
+package at.bitfire.davdroid.test;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+
+import android.util.Log;
+
+public class Constants {
+	public static final String ROBOHYDRA_BASE = "http://10.0.0.11:3000/";
+	
+	public static URI roboHydra;
+	static {
+		try {
+			roboHydra = new URI(ROBOHYDRA_BASE);
+		} catch(URISyntaxException e) {
+			Log.wtf("davdroid.test.Constants", "Invalid RoboHydra base URL");
+		}
+	}
+}

app/src/androidTest/java/at/bitfire/davdroid/test/ContactTest.java

@@ -0,0 +1,62 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.test;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import lombok.Cleanup;
+import net.fortuna.ical4j.data.ParserException;
+import android.content.res.AssetManager;
+import android.test.InstrumentationTestCase;
+import at.bitfire.davdroid.resource.Contact;
+import ezvcard.property.Impp;
+
+public class ContactTest extends InstrumentationTestCase {
+	AssetManager assetMgr;
+	
+	public void setUp() {
+		assetMgr = getInstrumentation().getContext().getResources().getAssets();
+	}
+	
+	public void testIMPP() throws IOException {
+		Contact c = parseVCard("impp.vcf");
+		assertEquals("test mctest", c.getDisplayName());
+		
+		Impp jabber = c.getImpps().get(0);
+		assertNull(jabber.getProtocol());
+		assertEquals("test-without-valid-scheme@test.tld", jabber.getHandle());
+	}
+
+	
+	public void testParseVcard3() throws IOException, ParserException {
+		Contact c = parseVCard("vcard3-sample1.vcf");
+		
+		assertEquals("Forrest Gump", c.getDisplayName());
+		assertEquals("Forrest", c.getGivenName());
+		assertEquals("Gump", c.getFamilyName());
+		
+		assertEquals(2, c.getPhoneNumbers().size());
+		assertEquals("(111) 555-1212", c.getPhoneNumbers().get(0).getText());
+		
+		assertEquals(1, c.getEmails().size());
+		assertEquals("forrestgump@example.com", c.getEmails().get(0).getValue());
+		
+		assertFalse(c.isStarred());
+	}
+
+	
+	private Contact parseVCard(String fileName) throws IOException {
+		@Cleanup InputStream in = assetMgr.open(fileName, AssetManager.ACCESS_STREAMING);
+		
+		Contact c = new Contact(fileName, null);
+		c.parseEntity(in);
+		
+		return c;
+	}
+}

app/src/androidTest/java/at/bitfire/davdroid/test/URLUtilsTest.java

@@ -0,0 +1,61 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.test;
+
+import java.net.URI;
+
+import junit.framework.TestCase;
+import at.bitfire.davdroid.URIUtils;
+
+
+public class URLUtilsTest extends TestCase {
+	
+	/* RFC 1738 p17 HTTP URLs:
+	hpath          = hsegment *[ "/" hsegment ]
+	hsegment       = *[ uchar | ";" | ":" | "@" | "&" | "=" ]
+	uchar          = unreserved | escape
+	unreserved     = alpha | digit | safe | extra
+	alpha          = lowalpha | hialpha
+	lowalpha       = ...
+	hialpha        = ...					
+	digit          = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" |
+	                 "8" | "9"
+	safe           = "$" | "-" | "_" | "." | "+"
+	extra          = "!" | "*" | "'" | "(" | ")" | ","
+	escape         = "%" hex hex
+	*/
+
+
+	public void testEnsureTrailingSlash() throws Exception {
+		assertEquals("/test/", URIUtils.ensureTrailingSlash("/test"));
+		assertEquals("/test/", URIUtils.ensureTrailingSlash("/test/"));
+
+		String	withoutSlash = "http://www.test.at/dav/collection",
+				withSlash = withoutSlash + "/";
+		assertEquals(new URI(withSlash), URIUtils.ensureTrailingSlash(new URI(withoutSlash)));
+		assertEquals(new URI(withSlash), URIUtils.ensureTrailingSlash(new URI(withSlash)));
+	}
+
+	public void testParseURI() throws Exception {
+		// don't escape valid characters
+		String validPath = "/;:@&=$-_.+!*'(),";
+		assertEquals(new URI("https://www.test.at:123" + validPath), URIUtils.parseURI("https://www.test.at:123" + validPath));
+		assertEquals(new URI(validPath), URIUtils.parseURI(validPath));
+		
+		// keep literal IPv6 addresses (only in host name)
+		assertEquals(new URI("https://[1:2::1]/"), URIUtils.parseURI("https://[1:2::1]/"));
+		
+		// ~ as home directory
+		assertEquals(new URI("http://www.test.at/~user1/"), URIUtils.parseURI("http://www.test.at/~user1/"));
+		assertEquals(new URI("http://www.test.at/~user1/"), URIUtils.parseURI("http://www.test.at/%7euser1/"));
+		
+		// @ in directory name
+		assertEquals(new URI("http://www.test.at/user@server.com/"), URIUtils.parseURI("http://www.test.at/user@server.com/"));
+		assertEquals(new URI("http://www.test.at/user@server.com/"), URIUtils.parseURI("http://www.test.at/user%40server.com/"));
+	}
+}

app/src/androidTest/java/at/bitfire/davdroid/webdav/DavRedirectStrategyTest.java

@@ -0,0 +1,73 @@
+package at.bitfire.davdroid.webdav;
+
+import java.io.IOException;
+
+import junit.framework.TestCase;
+import at.bitfire.davdroid.test.Constants;
+import ch.boye.httpclientandroidlib.HttpResponse;
+import ch.boye.httpclientandroidlib.client.methods.HttpOptions;
+import ch.boye.httpclientandroidlib.client.methods.HttpUriRequest;
+import ch.boye.httpclientandroidlib.client.protocol.HttpClientContext;
+import ch.boye.httpclientandroidlib.impl.client.CloseableHttpClient;
+import ch.boye.httpclientandroidlib.impl.client.HttpClientBuilder;
+import ch.boye.httpclientandroidlib.protocol.HttpContext;
+
+public class DavRedirectStrategyTest extends TestCase {
+	
+	CloseableHttpClient httpClient;
+	DavRedirectStrategy strategy = DavRedirectStrategy.INSTANCE;
+	
+	@Override
+	protected void setUp() {
+		httpClient = HttpClientBuilder.create()
+				.useSystemProperties()
+				.disableRedirectHandling()
+				.build();
+	}
+	
+	@Override
+	protected void tearDown() throws IOException {
+		httpClient.close();
+	}
+	
+	
+	// happy cases
+	
+	public void testNonRedirection() throws Exception {
+		HttpUriRequest request = new HttpOptions(Constants.roboHydra);
+		HttpResponse response = httpClient.execute(request);
+		assertFalse(strategy.isRedirected(request, response, null));
+	}
+	
+	public void testDefaultRedirection() throws Exception {
+		final String newLocation = "/new-location";
+		
+		HttpContext context = HttpClientContext.create();
+		HttpUriRequest request = new HttpOptions(Constants.roboHydra.resolve("redirect/301?to=" + newLocation));
+		HttpResponse response = httpClient.execute(request, context);
+		assertTrue(strategy.isRedirected(request, response, context));
+		
+		HttpUriRequest redirected = strategy.getRedirect(request, response, context);
+		assertEquals(Constants.roboHydra.resolve(newLocation), redirected.getURI());
+	}
+	
+	
+	// error cases
+	
+	public void testMissingLocation() throws Exception {
+		HttpContext context = HttpClientContext.create();
+		HttpUriRequest request = new HttpOptions(Constants.roboHydra.resolve("redirect/without-location"));
+		HttpResponse response = httpClient.execute(request, context);
+		assertFalse(strategy.isRedirected(request, response, context));
+	}
+	
+	public void testRelativeLocation() throws Exception {
+		HttpContext context = HttpClientContext.create();
+		HttpUriRequest request = new HttpOptions(Constants.roboHydra.resolve("redirect/relative"));
+		HttpResponse response = httpClient.execute(request, context);
+		assertTrue(strategy.isRedirected(request, response, context));
+		
+		HttpUriRequest redirected = strategy.getRedirect(request, response, context);
+		assertEquals(Constants.roboHydra.resolve("/new/location"), redirected.getURI());
+	}
+}

app/src/androidTest/java/at/bitfire/davdroid/webdav/TlsSniSocketFactoryTest.java

@@ -0,0 +1,27 @@
+package at.bitfire.davdroid.webdav;
+
+import java.io.IOException;
+
+import javax.net.ssl.SSLSocket;
+
+import android.util.Log;
+import junit.framework.TestCase;
+
+public class TlsSniSocketFactoryTest extends TestCase {
+	private static final String TAG = "davdroid.TlsSniSocketFactoryTest";
+	
+	public void testCiphers() throws IOException {
+		SSLSocket socket = (SSLSocket)TlsSniSocketFactory.INSTANCE.createSocket(null);
+
+		Log.i(TAG, "Enabled:");
+		for (String cipher : socket.getEnabledCipherSuites())
+			Log.i(TAG, cipher);
+		
+		Log.i(TAG, "Supported:");
+		for (String cipher : socket.getSupportedCipherSuites())
+			Log.i(TAG, cipher);
+		
+		assert(true);
+	}
+
+}

app/src/androidTest/java/at/bitfire/davdroid/webdav/WebDavResourceTest.java

@@ -0,0 +1,233 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import java.io.InputStream;
+import java.net.URI;
+import java.util.Arrays;
+import java.util.List;
+
+import javax.net.ssl.SSLPeerUnverifiedException;
+
+import lombok.Cleanup;
+
+import org.apache.commons.io.IOUtils;
+
+import android.content.res.AssetManager;
+import android.test.InstrumentationTestCase;
+import at.bitfire.davdroid.test.Constants;
+import at.bitfire.davdroid.webdav.HttpPropfind.Mode;
+import at.bitfire.davdroid.webdav.WebDavResource.PutMode;
+import ch.boye.httpclientandroidlib.impl.client.CloseableHttpClient;
+
+// tests require running robohydra!
+
+public class WebDavResourceTest extends InstrumentationTestCase {
+	static byte[] SAMPLE_CONTENT = new byte[] { 1, 2, 3, 4, 5 };
+	
+	final static String PATH_SIMPLE_FILE = "collection/new.file";
+	
+	AssetManager assetMgr;
+	CloseableHttpClient httpClient;
+	
+	WebDavResource baseDAV;
+	WebDavResource simpleFile,
+		davCollection, davNonExistingFile, davExistingFile,
+		davInvalid;
+
+	@Override
+	protected void setUp() throws Exception {
+		httpClient = DavHttpClient.create(true, true);
+				
+		assetMgr = getInstrumentation().getContext().getResources().getAssets();
+		
+		baseDAV = new WebDavResource(httpClient, Constants.roboHydra.resolve("/dav/"));
+		
+		simpleFile = new WebDavResource(httpClient, Constants.roboHydra.resolve("assets/test.random"));
+		
+		davCollection = new WebDavResource(httpClient, Constants.roboHydra.resolve("dav/"));
+		davNonExistingFile = new WebDavResource(davCollection, "collection/new.file");
+		davExistingFile = new WebDavResource(davCollection, "collection/existing.file");
+		
+		davInvalid = new WebDavResource(httpClient, Constants.roboHydra.resolve("dav-invalid/"));
+	}
+	
+	@Override
+	protected void tearDown() throws Exception {
+		httpClient.close();
+	}
+
+
+	/* test feature detection */
+	
+	public void testOptions() throws Exception {
+		String[]	davMethods = new String[] { "PROPFIND", "GET", "PUT", "DELETE", "REPORT" },
+					davCapabilities = new String[] { "addressbook", "calendar-access" };
+		
+		WebDavResource capable = new WebDavResource(baseDAV);
+		capable.options();
+		for (String davMethod : davMethods)
+			assertTrue(capable.supportsMethod(davMethod));
+		for (String capability : davCapabilities)
+			assertTrue(capable.supportsDAV(capability));
+	}
+
+	public void testPropfindCurrentUserPrincipal() throws Exception {
+		davCollection.propfind(HttpPropfind.Mode.CURRENT_USER_PRINCIPAL);
+		assertEquals("/dav/principals/users/test", davCollection.getCurrentUserPrincipal());
+		
+		try {
+			simpleFile.propfind(HttpPropfind.Mode.CURRENT_USER_PRINCIPAL);
+			fail();
+			
+		} catch(DavException ex) {
+		}
+		assertNull(simpleFile.getCurrentUserPrincipal());
+	}
+		
+	public void testPropfindHomeSets() throws Exception {
+		WebDavResource dav = new WebDavResource(davCollection, "principals/users/test");
+		dav.propfind(HttpPropfind.Mode.HOME_SETS);
+		assertEquals("/dav/addressbooks/test/", dav.getAddressbookHomeSet());
+		assertEquals("/dav/calendars/test/", dav.getCalendarHomeSet());
+	}
+	
+	public void testPropfindAddressBooks() throws Exception {
+		WebDavResource dav = new WebDavResource(davCollection, "addressbooks/test");
+		dav.propfind(HttpPropfind.Mode.CARDDAV_COLLECTIONS);
+		assertEquals(2, dav.getMembers().size());
+		for (WebDavResource member : dav.getMembers()) {
+			if (member.getName().equals("default-v4.vcf"))
+				assertTrue(member.isAddressBook());
+			else
+				assertFalse(member.isAddressBook());
+			assertFalse(member.isCalendar());
+		}
+	}
+	
+	public void testPropfindCalendars() throws Exception {
+		WebDavResource dav = new WebDavResource(davCollection, "calendars/test");
+		dav.propfind(Mode.CALDAV_COLLECTIONS);
+		assertEquals(3, dav.getMembers().size());
+		assertEquals("0xFF00FF", dav.getMembers().get(2).getColor());
+		for (WebDavResource member : dav.getMembers()) {
+			if (member.getName().contains(".ics"))
+				assertTrue(member.isCalendar());
+			else
+				assertFalse(member.isCalendar());
+			assertFalse(member.isAddressBook());
+		}
+	}
+	
+	public void testPropfindTrailingSlashes() throws Exception {
+		final String principalOK = "/principals/ok";
+		
+		String requestPaths[] = {
+			"/dav/collection-response-with-trailing-slash",
+			"/dav/collection-response-with-trailing-slash/",
+			"/dav/collection-response-without-trailing-slash",
+			"/dav/collection-response-without-trailing-slash/"
+		};
+		
+		for (String path : requestPaths) {
+			WebDavResource davSlash = new WebDavResource(davCollection, path);
+			davSlash.propfind(Mode.CARDDAV_COLLECTIONS);
+			assertEquals(principalOK, davSlash.getCurrentUserPrincipal());
+		}
+	}
+	
+	
+	/* test normal HTTP/WebDAV */
+	
+	public void testPropfindRedirection() throws Exception {
+		// PROPFIND redirection
+		WebDavResource redirected = new WebDavResource(baseDAV, "/redirect/301?to=/dav/");
+		redirected.propfind(Mode.CURRENT_USER_PRINCIPAL);
+		assertEquals("/dav/", redirected.getLocation().getPath());
+	}
+	
+	public void testGet() throws Exception {
+		simpleFile.get("*/*");
+		@Cleanup InputStream is = assetMgr.open("test.random", AssetManager.ACCESS_STREAMING);
+		byte[] expected = IOUtils.toByteArray(is);
+		assertTrue(Arrays.equals(expected, simpleFile.getContent()));
+	}
+	
+	public void testGetHttpsWithSni() throws Exception {
+		WebDavResource file = new WebDavResource(httpClient, new URI("https://sni.velox.ch"));
+		
+		boolean	sniWorking = false;
+		try {
+			file.get("*/*");
+			sniWorking = true; 
+		} catch (SSLPeerUnverifiedException e) {
+		}
+		
+		assertTrue(sniWorking);
+	}
+	
+	public void testMultiGet() throws Exception {
+		WebDavResource davAddressBook = new WebDavResource(davCollection, "addressbooks/default.vcf");
+		davAddressBook.multiGet(DavMultiget.Type.ADDRESS_BOOK, new String[] { "1.vcf", "2.vcf" });
+		assertEquals("My Book", davAddressBook.getDisplayName());
+		assertEquals(2, davAddressBook.getMembers().size());
+		for (WebDavResource member : davAddressBook.getMembers())
+			assertNotNull(member.getContent());
+	}
+	
+	public void testPutAddDontOverwrite() throws Exception {
+		// should succeed on a non-existing file
+		assertEquals("has-just-been-created", davNonExistingFile.put(SAMPLE_CONTENT, PutMode.ADD_DONT_OVERWRITE));
+		
+		// should fail on an existing file
+		try {
+			davExistingFile.put(SAMPLE_CONTENT, PutMode.ADD_DONT_OVERWRITE);
+			fail();
+		} catch(PreconditionFailedException ex) {
+		}
+	}
+	
+	public void testPutUpdateDontOverwrite() throws Exception  {
+		// should succeed on an existing file
+		assertEquals("has-just-been-updated", davExistingFile.put(SAMPLE_CONTENT, PutMode.UPDATE_DONT_OVERWRITE));
+		
+		// should fail on a non-existing file
+		try {
+			davNonExistingFile.put(SAMPLE_CONTENT, PutMode.UPDATE_DONT_OVERWRITE);
+			fail();
+		} catch(PreconditionFailedException ex) {
+		}
+	}
+	
+	public void testDelete() throws Exception {
+		// should succeed on an existing file
+		davExistingFile.delete();
+		
+		// should fail on a non-existing file
+		try {
+			davNonExistingFile.delete();
+			fail();
+		} catch (NotFoundException e) {
+		}
+	}
+	
+	
+	/* test CalDAV/CardDAV */
+	
+	
+	/* special test */
+	
+	public void testInvalidURLs() throws Exception {
+		WebDavResource dav = new WebDavResource(davInvalid, "addressbooks/%7euser1/");
+		dav.propfind(HttpPropfind.Mode.CARDDAV_COLLECTIONS);
+		List<WebDavResource> members = dav.getMembers();
+		assertEquals(1, members.size());
+		assertEquals(Constants.ROBOHYDRA_BASE + "dav-invalid/addressbooks/~user1/My%20Contacts:1.vcf/", members.get(0).getLocation().toASCIIString());
+	}
+	
+}

app/src/androidTest/res/values/strings.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+
+    <string name="app_name">DavdroidTest</string>
+
+</resources>

app/src/main/AndroidManifest.xml

@@ -0,0 +1,79 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="at.bitfire.davdroid"
+    android:versionCode="47"
+    android:versionName="0.6.8" android:installLocation="internalOnly">
+
+    <uses-sdk
+        android:minSdkVersion="14"
+        android:targetSdkVersion="21" />
+
+    <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.AUTHENTICATE_ACCOUNTS" />
+    <uses-permission android:name="android.permission.READ_CONTACTS" />
+    <uses-permission android:name="android.permission.WRITE_CONTACTS" />
+    <uses-permission android:name="android.permission.READ_CALENDAR" />
+    <uses-permission android:name="android.permission.WRITE_CALENDAR" />
+    <uses-permission android:name="android.permission.WRITE_SYNC_SETTINGS" />
+
+    <application
+        android:allowBackup="true"
+        android:icon="@drawable/ic_launcher"
+        android:label="@string/app_name"
+        android:theme="@style/AppTheme"
+        android:process=":sync" >
+        <service
+            android:name=".syncadapter.AccountAuthenticatorService"
+            android:exported="false" >
+            <intent-filter>
+                <action android:name="android.accounts.AccountAuthenticator" />
+            </intent-filter>
+
+            <meta-data
+                android:name="android.accounts.AccountAuthenticator"
+                android:resource="@xml/account_authenticator" />
+        </service>
+        <service
+            android:name=".syncadapter.ContactsSyncAdapterService"
+            android:exported="true" >
+            <intent-filter>
+                <action android:name="android.content.SyncAdapter" />
+            </intent-filter>
+
+            <meta-data
+                android:name="android.content.SyncAdapter"
+                android:resource="@xml/sync_contacts" />
+            <meta-data
+                android:name="android.provider.CONTACTS_STRUCTURE"
+                android:resource="@xml/contacts" />
+        </service>
+        <service
+            android:name=".syncadapter.CalendarsSyncAdapterService"
+            android:exported="true" >
+            <intent-filter>
+                <action android:name="android.content.SyncAdapter" />
+            </intent-filter>
+
+            <meta-data
+                android:name="android.content.SyncAdapter"
+                android:resource="@xml/sync_calendars" />
+        </service>
+
+        <activity
+            android:name=".MainActivity"
+            android:label="@string/app_name" >
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+        <activity
+            android:name=".syncadapter.AddAccountActivity"
+            android:excludeFromRecents="true" >
+        </activity>
+        <activity
+            android:name=".syncadapter.GeneralSettingsActivity" >
+        </activity>
+        </application>
+
+</manifest>

app/src/main/java/at/bitfire/davdroid/ArrayUtils.java

@@ -0,0 +1,33 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid;
+
+import java.lang.reflect.Array;
+
+public class ArrayUtils {
+
+	@SuppressWarnings("unchecked")
+	public static <T> T[][] partition(T[] bigArray, int max) {
+		int nItems = bigArray.length;
+		int nPartArrays = (nItems + max-1)/max;
+		
+		T[][] partArrays = (T[][])Array.newInstance(bigArray.getClass().getComponentType(), nPartArrays, 0); 
+		
+		// nItems is now the number of remaining items
+		for (int i = 0; nItems > 0; i++) {
+			int n = (nItems < max) ? nItems : max;
+			partArrays[i] = (T[])Array.newInstance(bigArray.getClass().getComponentType(), n); 
+			System.arraycopy(bigArray, i*max, partArrays[i], 0, n);
+			
+			nItems -= n;
+		}
+		
+		return partArrays;
+	}
+	
+}

app/src/main/java/at/bitfire/davdroid/Constants.java

@@ -0,0 +1,18 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid;
+
+public class Constants {
+	public static final String
+		APP_VERSION = "0.6.9",
+		ACCOUNT_TYPE = "bitfire.at.davdroid",
+		WEB_URL_HELP = "https://davdroid.bitfire.at/configuration?pk_campaign=davdroid-app",
+		
+		SETTING_DISABLE_COMPRESSION = "disable_compression",
+		SETTING_NETWORK_LOGGING = "network_logging";
+}

app/src/main/java/at/bitfire/davdroid/MainActivity.java

@@ -0,0 +1,82 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid;
+
+import android.app.Activity;
+import android.content.Intent;
+import android.net.Uri;
+import android.os.Bundle;
+import android.provider.Settings;
+import android.text.Html;
+import android.text.method.LinkMovementMethod;
+import android.view.Menu;
+import android.view.MenuInflater;
+import android.view.MenuItem;
+import android.view.View;
+import android.widget.TextView;
+import at.bitfire.davdroid.syncadapter.AddAccountActivity;
+import at.bitfire.davdroid.syncadapter.GeneralSettingsActivity;
+
+public class MainActivity extends Activity {
+
+	@Override
+	protected void onCreate(Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+		
+		setContentView(R.layout.activity_main);
+		
+		TextView tvWorkaround = (TextView)findViewById(R.id.text_workaround);
+		if (fromPlayStore()) {
+			tvWorkaround.setVisibility(View.VISIBLE);
+			tvWorkaround.setText(Html.fromHtml(getString(R.string.html_main_workaround)));
+		    tvWorkaround.setMovementMethod(LinkMovementMethod.getInstance());
+		}
+		
+		TextView tvInfo = (TextView)findViewById(R.id.text_info);
+		tvInfo.setText(Html.fromHtml(getString(R.string.html_main_info, Constants.APP_VERSION)));
+		tvInfo.setMovementMethod(LinkMovementMethod.getInstance());
+	}
+
+	@Override
+	public boolean onCreateOptionsMenu(Menu menu) {
+		MenuInflater inflater = getMenuInflater();
+	    inflater.inflate(R.menu.main_activity, menu);
+	    return true;
+	}
+
+	
+	public void addAccount(MenuItem item) {
+		Intent intent = new Intent(this, AddAccountActivity.class);
+		startActivity(intent);
+	}
+	
+	public void showDebugSettings(MenuItem item) {
+		Intent intent = new Intent(this, GeneralSettingsActivity.class);
+		startActivity(intent);
+	}
+
+	public void showSyncSettings(MenuItem item) {
+		Intent intent = new Intent(Settings.ACTION_SYNC_SETTINGS);
+		startActivity(intent);
+	}
+
+	public void showWebsite(MenuItem item) {
+		Intent intent = new Intent(Intent.ACTION_VIEW);
+		intent.setData(Uri.parse(Constants.WEB_URL_HELP + "&pk_kwd=main-activity"));
+		startActivity(intent);
+	}
+	
+	
+	private boolean fromPlayStore() {
+		try {
+			return "com.android.vending".equals(getPackageManager().getInstallerPackageName("at.bitfire.davdroid"));
+		} catch(IllegalArgumentException e) {
+		}
+		return false;
+	}
+}

app/src/main/java/at/bitfire/davdroid/URIUtils.java

@@ -0,0 +1,53 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+
+import android.util.Log;
+
+public class URIUtils {
+	private static final String TAG = "davdroid.URIUtils";
+
+	
+	public static String ensureTrailingSlash(String href) {
+		if (!href.endsWith("/")) {
+			Log.d(TAG, "Implicitly appending trailing slash to collection " + href);
+			return href + "/";
+		} else
+			return href;
+	}
+	
+	public static URI ensureTrailingSlash(URI href) {
+		if (!href.getPath().endsWith("/")) {
+			try {
+				URI newURI = new URI(href.getScheme(), href.getAuthority(), href.getPath() + "/", null, null);
+				Log.d(TAG, "Appended trailing slash to collection " + href + " -> " + newURI);
+				href = newURI;
+			} catch (URISyntaxException e) {
+			}
+		}
+		return href;
+	}
+
+
+	/**
+	 * Parse a received absolute/relative URL and generate a normalized URI that can be compared.
+	 * @param original	URI to be parsed, may be absolute or relative 
+	 * @return			normalized URI
+	 * @throws URISyntaxException
+	 */
+	public static URI parseURI(String original) throws URISyntaxException {
+		URI raw = URI.create(original);
+		URI uri = new URI(raw.getScheme(), raw.getAuthority(), raw.getPath(), raw.getQuery(), raw.getFragment());
+		Log.v(TAG, "Normalized URL " + original + " -> " + uri.toASCIIString());
+		return uri;
+	}
+
+}

app/src/main/java/at/bitfire/davdroid/resource/CalDavCalendar.java

@@ -0,0 +1,37 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.resource;
+
+import java.net.URISyntaxException;
+
+import at.bitfire.davdroid.webdav.DavMultiget;
+import org.apache.http.impl.client.CloseableHttpClient;
+
+public class CalDavCalendar extends RemoteCollection<Event> { 
+	//private final static String TAG = "davdroid.CalDavCalendar";
+	
+	@Override
+	protected String memberContentType() {
+		return "text/calendar";
+	}
+
+	@Override
+	protected DavMultiget.Type multiGetType() {
+		return DavMultiget.Type.CALENDAR;
+	}
+	
+	@Override
+	protected Event newResourceSkeleton(String name, String ETag) {
+		return new Event(name, ETag);
+	}
+	
+	
+	public CalDavCalendar(CloseableHttpClient httpClient, String baseURL, String user, String password, boolean preemptiveAuth) throws URISyntaxException {
+		super(httpClient, baseURL, user, password, preemptiveAuth);
+	}
+}

app/src/main/java/at/bitfire/davdroid/resource/CardDavAddressBook.java

@@ -0,0 +1,37 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.resource;
+
+import java.net.URISyntaxException;
+
+import at.bitfire.davdroid.webdav.DavMultiget;
+import org.apache.http.impl.client.CloseableHttpClient;
+
+public class CardDavAddressBook extends RemoteCollection<Contact> {
+	//private final static String TAG = "davdroid.CardDavAddressBook"; 
+	
+	@Override
+	protected String memberContentType() {
+		return Contact.MIME_TYPE;
+	}
+	
+	@Override
+	protected DavMultiget.Type multiGetType() {
+		return DavMultiget.Type.ADDRESS_BOOK;
+	}
+
+	@Override
+	protected Contact newResourceSkeleton(String name, String ETag) {
+		return new Contact(name, ETag);
+	}
+	
+
+	public CardDavAddressBook(CloseableHttpClient httpClient, String baseURL, String user, String password, boolean preemptiveAuth) throws URISyntaxException {
+		super(httpClient, baseURL, user, password, preemptiveAuth);
+	}
+}

app/src/main/java/at/bitfire/davdroid/resource/Contact.java

@@ -0,0 +1,410 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.resource;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.UUID;
+
+import lombok.Getter;
+import lombok.Setter;
+import lombok.ToString;
+
+import org.apache.commons.lang.StringUtils;
+
+import android.util.Log;
+import at.bitfire.davdroid.Constants;
+import ezvcard.Ezvcard;
+import ezvcard.VCard;
+import ezvcard.VCardVersion;
+import ezvcard.ValidationWarnings;
+import ezvcard.parameter.EmailType;
+import ezvcard.parameter.ImageType;
+import ezvcard.parameter.TelephoneType;
+import ezvcard.property.Address;
+import ezvcard.property.Anniversary;
+import ezvcard.property.Birthday;
+import ezvcard.property.Categories;
+import ezvcard.property.Email;
+import ezvcard.property.FormattedName;
+import ezvcard.property.Impp;
+import ezvcard.property.Logo;
+import ezvcard.property.Nickname;
+import ezvcard.property.Note;
+import ezvcard.property.Organization;
+import ezvcard.property.Photo;
+import ezvcard.property.RawProperty;
+import ezvcard.property.Revision;
+import ezvcard.property.Role;
+import ezvcard.property.Sound;
+import ezvcard.property.Source;
+import ezvcard.property.StructuredName;
+import ezvcard.property.Telephone;
+import ezvcard.property.Title;
+import ezvcard.property.Uid;
+import ezvcard.property.Url;
+
+
+/**
+ * Represents a contact. Locally, this is a Contact in the Android
+ * device; remote, this is a VCard.
+ */
+@ToString(callSuper = true)
+public class Contact extends Resource {
+	private final static String TAG = "davdroid.Contact";
+	
+	public final static String MIME_TYPE = "text/vcard";
+	
+	public final static String
+		PROPERTY_STARRED = "X-DAVDROID-STARRED",
+		PROPERTY_PHONETIC_FIRST_NAME = "X-PHONETIC-FIRST-NAME",
+		PROPERTY_PHONETIC_MIDDLE_NAME = "X-PHONETIC-MIDDLE-NAME",
+		PROPERTY_PHONETIC_LAST_NAME = "X-PHONETIC-LAST-NAME",
+		PROPERTY_SIP = "X-SIP";
+		
+	public final static EmailType EMAIL_TYPE_MOBILE = EmailType.get("X-MOBILE");
+
+	public final static TelephoneType
+		PHONE_TYPE_CALLBACK = TelephoneType.get("X-CALLBACK"),
+		PHONE_TYPE_COMPANY_MAIN = TelephoneType.get("X-COMPANY_MAIN"),
+		PHONE_TYPE_RADIO = TelephoneType.get("X-RADIO"),
+		PHONE_TYPE_ASSISTANT = TelephoneType.get("X-ASSISTANT"),
+		PHONE_TYPE_MMS = TelephoneType.get("X-MMS");
+	
+	@Getter @Setter private String unknownProperties;
+	
+	@Getter @Setter private boolean starred;
+	
+	@Getter @Setter private String displayName, nickName;
+	@Getter @Setter private String prefix, givenName, middleName, familyName, suffix;
+	@Getter @Setter private String phoneticGivenName, phoneticMiddleName, phoneticFamilyName;
+	@Getter @Setter private String note;
+	@Getter @Setter private Organization organization;
+	@Getter @Setter private String jobTitle, jobDescription;
+	
+	@Getter @Setter private byte[] photo;
+	
+	@Getter @Setter private Anniversary anniversary;
+	@Getter @Setter private Birthday birthDay;
+
+	@Getter private List<Telephone> phoneNumbers = new LinkedList<Telephone>();
+	@Getter private List<Email> emails = new LinkedList<Email>();
+	@Getter private List<Impp> impps = new LinkedList<Impp>();
+	@Getter private List<Address> addresses = new LinkedList<Address>();
+	@Getter private List<String> categories = new LinkedList<String>();
+	@Getter private List<String> URLs = new LinkedList<String>();
+
+
+	/* instance methods */
+	
+	public Contact(String name, String ETag) {
+		super(name, ETag);
+	}
+	
+	public Contact(long localID, String resourceName, String eTag) {
+		super(localID, resourceName, eTag);
+	}
+	
+	
+	@Override
+	public void initialize() {
+		generateUID();
+		name = uid + ".vcf";
+	}
+	
+	protected void generateUID() {
+		uid = UUID.randomUUID().toString();
+	}
+
+	
+	/* VCard methods */
+
+	@Override
+	public void parseEntity(InputStream is) throws IOException {
+		VCard vcard = Ezvcard.parse(is).first();
+		if (vcard == null)
+			return;
+		
+		// now work through all supported properties
+		// supported properties are removed from the VCard after parsing
+		// so that only unknown properties are left and can be stored separately
+		
+		// UID
+		Uid uid = vcard.getUid();
+		if (uid != null) {
+			this.uid = uid.getValue();
+			vcard.removeProperties(Uid.class);
+		} else {
+			Log.w(TAG, "Received VCard without UID, generating new one");
+			generateUID();
+		}
+
+		// X-DAVDROID-STARRED
+		RawProperty starred = vcard.getExtendedProperty(PROPERTY_STARRED);
+		if (starred != null && starred.getValue() != null) {
+			this.starred = starred.getValue().equals("1");
+			vcard.removeExtendedProperty(PROPERTY_STARRED);
+		} else
+			this.starred = false;
+		
+		// FN
+		FormattedName fn = vcard.getFormattedName();
+		if (fn != null) {
+			displayName = fn.getValue();
+			vcard.removeProperties(FormattedName.class);
+		} else
+			Log.w(TAG, "Received invalid VCard without FN (formatted name) property");
+
+		// N
+		StructuredName n = vcard.getStructuredName();
+		if (n != null) {
+			prefix = StringUtils.join(n.getPrefixes(), " ");
+			givenName = n.getGiven();
+			middleName = StringUtils.join(n.getAdditional(), " ");
+			familyName = n.getFamily();
+			suffix = StringUtils.join(n.getSuffixes(), " ");
+			vcard.removeProperties(StructuredName.class);
+		}
+		
+		// phonetic names
+		RawProperty
+			phoneticFirstName = vcard.getExtendedProperty(PROPERTY_PHONETIC_FIRST_NAME),
+			phoneticMiddleName = vcard.getExtendedProperty(PROPERTY_PHONETIC_MIDDLE_NAME),
+			phoneticLastName = vcard.getExtendedProperty(PROPERTY_PHONETIC_LAST_NAME);
+		if (phoneticFirstName != null) {
+			phoneticGivenName = phoneticFirstName.getValue();
+			vcard.removeExtendedProperty(PROPERTY_PHONETIC_FIRST_NAME);
+		}
+		if (phoneticMiddleName != null) {
+			this.phoneticMiddleName = phoneticMiddleName.getValue();
+			vcard.removeExtendedProperty(PROPERTY_PHONETIC_MIDDLE_NAME);
+		}
+		if (phoneticLastName != null) {
+			phoneticFamilyName = phoneticLastName.getValue();
+			vcard.removeExtendedProperty(PROPERTY_PHONETIC_LAST_NAME);
+		}
+		
+		// TEL
+		phoneNumbers = vcard.getTelephoneNumbers();
+		vcard.removeProperties(Telephone.class);
+		
+		// EMAIL
+		emails = vcard.getEmails();
+		vcard.removeProperties(Email.class);
+		
+		// PHOTO
+		for (Photo photo : vcard.getPhotos()) {
+			this.photo = photo.getData();
+			vcard.removeProperties(Photo.class);
+			break;
+		}
+
+		// ORG
+		organization = vcard.getOrganization();
+		vcard.removeProperties(Organization.class);
+		// TITLE
+		for (Title title : vcard.getTitles()) {
+			jobTitle = title.getValue();
+			vcard.removeProperties(Title.class);
+			break;
+		}
+		// ROLE
+		for (Role role : vcard.getRoles()) {
+			this.jobDescription = role.getValue();
+			vcard.removeProperties(Role.class);
+			break;
+		}
+	
+		// IMPP
+		impps = vcard.getImpps();
+		vcard.removeProperties(Impp.class);
+		
+		// NICKNAME
+		Nickname nicknames = vcard.getNickname();
+		if (nicknames != null) {
+			if (nicknames.getValues() != null)
+				nickName = StringUtils.join(nicknames.getValues(), ", ");
+			vcard.removeProperties(Nickname.class);
+		}
+		
+		// NOTE
+		List<String> notes = new LinkedList<String>();
+		for (Note note : vcard.getNotes())
+			notes.add(note.getValue());
+		if (!notes.isEmpty())
+			note = StringUtils.join(notes, "\n---\n");
+		vcard.removeProperties(Note.class);
+
+		// ADR
+		addresses = vcard.getAddresses();
+		vcard.removeProperties(Address.class);
+		
+		// CATEGORY
+		Categories categories = vcard.getCategories();
+		if (categories != null)
+			this.categories = categories.getValues();
+		vcard.removeProperties(Categories.class);
+		
+		// URL
+		for (Url url : vcard.getUrls())
+			URLs.add(url.getValue());
+		vcard.removeProperties(Url.class);
+
+		// BDAY
+		birthDay = vcard.getBirthday();
+		vcard.removeProperties(Birthday.class);
+		// ANNIVERSARY
+		anniversary = vcard.getAnniversary();
+		vcard.removeProperties(Anniversary.class);
+		
+		// X-SIP
+		for (RawProperty sip : vcard.getExtendedProperties(PROPERTY_SIP))
+			impps.add(new Impp("sip", sip.getValue()));
+		vcard.removeExtendedProperty(PROPERTY_SIP);
+
+		// remove binary properties because of potential OutOfMemory / TransactionTooLarge exceptions
+		vcard.removeProperties(Logo.class);
+		vcard.removeProperties(Sound.class);
+		// remove properties that don't apply anymore
+		vcard.removeProperties(Revision.class);
+		vcard.removeProperties(Source.class);
+		// store all remaining properties into unknownProperties
+		if (!vcard.getProperties().isEmpty() || !vcard.getExtendedProperties().isEmpty())
+			try {
+				unknownProperties = vcard.write();
+			} catch(Exception e) {
+				Log.w(TAG, "Couldn't store unknown properties (maybe illegal syntax), dropping them");
+			}
+	}
+
+	
+	@Override
+	public ByteArrayOutputStream toEntity() throws IOException {
+		VCard vcard = null;
+		try {
+			if (unknownProperties != null)
+				vcard = Ezvcard.parse(unknownProperties).first();
+		} catch (Exception e) {
+			Log.w(TAG, "Couldn't parse original property set, beginning from scratch");
+		}
+		if (vcard == null)
+			vcard = new VCard();
+		
+		if (uid != null)
+			vcard.setUid(new Uid(uid));
+		else
+			Log.wtf(TAG, "Generating VCard without UID");
+		
+		if (starred)
+			vcard.setExtendedProperty(PROPERTY_STARRED, "1");
+		
+		if (displayName != null)
+			vcard.setFormattedName(displayName);
+		else if (organization != null && organization.getValues() != null && organization.getValues().get(0) != null)
+			vcard.setFormattedName(organization.getValues().get(0));
+		else
+			Log.w(TAG, "No FN (formatted name) available to generate VCard");
+
+		// N
+		if (familyName != null || middleName != null || givenName != null) {
+			StructuredName n = new StructuredName();
+			if (prefix != null)
+				for (String p : StringUtils.split(prefix))
+					n.addPrefix(p);
+			n.setGiven(givenName);
+			if (middleName != null)
+				for (String middle : StringUtils.split(middleName))
+					n.addAdditional(middle);
+			n.setFamily(familyName);
+			if (suffix != null)
+				for (String s : StringUtils.split(suffix))
+					n.addSuffix(s);
+			vcard.setStructuredName(n);
+		}
+		
+		// phonetic names
+		if (phoneticGivenName != null)
+			vcard.addExtendedProperty(PROPERTY_PHONETIC_FIRST_NAME, phoneticGivenName);
+		if (phoneticMiddleName != null)
+			vcard.addExtendedProperty(PROPERTY_PHONETIC_MIDDLE_NAME, phoneticMiddleName);
+		if (phoneticFamilyName != null)
+			vcard.addExtendedProperty(PROPERTY_PHONETIC_LAST_NAME, phoneticFamilyName);
+		
+		// TEL
+		for (Telephone phoneNumber : phoneNumbers)
+			vcard.addTelephoneNumber(phoneNumber);
+		
+		// EMAIL
+		for (Email email : emails)
+			vcard.addEmail(email);
+
+		// ORG, TITLE, ROLE
+		if (organization != null)
+			vcard.setOrganization(organization);
+		if (jobTitle != null)
+			vcard.addTitle(jobTitle);
+		if (jobDescription != null)
+			vcard.addRole(jobDescription);
+		
+		// IMPP
+		for (Impp impp : impps)
+			vcard.addImpp(impp);
+
+		// NICKNAME
+		if (!StringUtils.isBlank(nickName))
+			vcard.setNickname(nickName);
+		
+		// NOTE
+		if (!StringUtils.isBlank(note))
+			vcard.addNote(note);
+		
+		// ADR
+		for (Address address : addresses)
+			vcard.addAddress(address);
+		
+		// CATEGORY
+		if (!categories.isEmpty())
+			vcard.setCategories(categories.toArray(new String[0]));
+		
+		// URL
+		for (String url : URLs)
+			vcard.addUrl(url);
+
+		// ANNIVERSARY
+		if (anniversary != null)
+			vcard.setAnniversary(anniversary);
+		// BDAY
+		if (birthDay != null)
+			vcard.setBirthday(birthDay);
+		
+		// PHOTO
+		if (photo != null)
+			vcard.addPhoto(new Photo(photo, ImageType.JPEG));
+		
+		// PRODID, REV
+		vcard.setProductId("DAVdroid/" + Constants.APP_VERSION + " (ez-vcard/" + Ezvcard.VERSION + ")");
+		vcard.setRevision(Revision.now());
+		
+		// validate and print warnings
+		ValidationWarnings warnings = vcard.validate(VCardVersion.V3_0);
+		if (!warnings.isEmpty())
+			Log.w(TAG, "Created potentially invalid VCard! " + warnings);
+		
+		ByteArrayOutputStream os = new ByteArrayOutputStream();
+		Ezvcard
+			.write(vcard)
+			.version(VCardVersion.V3_0)
+			.versionStrict(false)
+			.prodId(false)		// we provide our own PRODID
+			.go(os);
+		return os;
+	}
+}

app/src/main/java/at/bitfire/davdroid/resource/DavResourceFinder.java

@@ -0,0 +1,298 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.resource;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.net.MalformedURLException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.LinkedList;
+import java.util.List;
+
+import org.xbill.DNS.Lookup;
+import org.xbill.DNS.Record;
+import org.xbill.DNS.SRVRecord;
+import org.xbill.DNS.TXTRecord;
+import org.xbill.DNS.TextParseException;
+import org.xbill.DNS.Type;
+
+import android.content.Context;
+import android.util.Log;
+import at.bitfire.davdroid.R;
+import at.bitfire.davdroid.webdav.DavException;
+import at.bitfire.davdroid.webdav.DavHttpClient;
+import at.bitfire.davdroid.webdav.DavIncapableException;
+import at.bitfire.davdroid.webdav.HttpPropfind.Mode;
+import at.bitfire.davdroid.webdav.NotAuthorizedException;
+import at.bitfire.davdroid.webdav.WebDavResource;
+import org.apache.http.HttpException;
+import org.apache.http.impl.client.CloseableHttpClient;
+import ezvcard.VCardVersion;
+
+public class DavResourceFinder implements Closeable {
+	private final static String TAG = "davdroid.DavResourceFinder";
+	
+	protected Context context;
+	protected CloseableHttpClient httpClient;
+	
+	
+	public DavResourceFinder(Context context) {
+		this.context = context;
+		
+		// disable compression and enable network logging for debugging purposes 
+		httpClient = DavHttpClient.create(true, true);
+	}
+
+	@Override
+	public void close() throws IOException {
+		httpClient.close();
+	}
+	
+	
+	public void findResources(ServerInfo serverInfo) throws URISyntaxException, DavException, HttpException, IOException {
+		// CardDAV
+		WebDavResource principal = getCurrentUserPrincipal(serverInfo, "carddav");
+		if (principal != null) {
+			serverInfo.setCardDAV(true);
+		
+			principal.propfind(Mode.HOME_SETS);
+			String pathAddressBooks = principal.getAddressbookHomeSet();
+			if (pathAddressBooks != null) {
+				Log.i(TAG, "Found address book home set: " + pathAddressBooks);
+			
+				WebDavResource homeSetAddressBooks = new WebDavResource(principal, pathAddressBooks);
+				if (checkHomesetCapabilities(homeSetAddressBooks, "addressbook")) {
+					homeSetAddressBooks.propfind(Mode.CARDDAV_COLLECTIONS);
+					
+					List<ServerInfo.ResourceInfo> addressBooks = new LinkedList<ServerInfo.ResourceInfo>();
+					if (homeSetAddressBooks.getMembers() != null)
+						for (WebDavResource resource : homeSetAddressBooks.getMembers())
+							if (resource.isAddressBook()) {
+								Log.i(TAG, "Found address book: " + resource.getLocation().getPath());
+								ServerInfo.ResourceInfo info = new ServerInfo.ResourceInfo(
+									ServerInfo.ResourceInfo.Type.ADDRESS_BOOK,
+									resource.isReadOnly(),
+									resource.getLocation().toString(),
+									resource.getDisplayName(),
+									resource.getDescription(), resource.getColor()
+								);
+								
+								VCardVersion version = resource.getVCardVersion();
+								if (version == null)
+									version = VCardVersion.V3_0;	// VCard 3.0 MUST be supported
+								info.setVCardVersion(version);
+								
+								addressBooks.add(info);
+							}
+					serverInfo.setAddressBooks(addressBooks);
+				} else
+					Log.w(TAG, "Found address-book home set, but it doesn't advertise CardDAV support");
+			}
+		}
+		
+		// CalDAV
+		principal = getCurrentUserPrincipal(serverInfo, "caldav");
+		if (principal != null) {
+			serverInfo.setCalDAV(true);
+
+			principal.propfind(Mode.HOME_SETS);
+			String pathCalendars = principal.getCalendarHomeSet();
+			if (pathCalendars != null) {
+				Log.i(TAG, "Found calendar home set: " + pathCalendars);
+			
+				WebDavResource homeSetCalendars = new WebDavResource(principal, pathCalendars);
+				if (checkHomesetCapabilities(homeSetCalendars, "calendar-access")) {
+					homeSetCalendars.propfind(Mode.CALDAV_COLLECTIONS);
+					
+					List<ServerInfo.ResourceInfo> calendars = new LinkedList<ServerInfo.ResourceInfo>();
+					if (homeSetCalendars.getMembers() != null)
+						for (WebDavResource resource : homeSetCalendars.getMembers())
+							if (resource.isCalendar()) {
+								Log.i(TAG, "Found calendar: " + resource.getLocation().getPath());
+								if (resource.getSupportedComponents() != null) {
+									// CALDAV:supported-calendar-component-set available
+									boolean supportsEvents = false;
+									for (String supportedComponent : resource.getSupportedComponents())
+										if (supportedComponent.equalsIgnoreCase("VEVENT"))
+											supportsEvents = true;
+									if (!supportsEvents) {	// ignore collections without VEVENT support
+										Log.i(TAG, "Ignoring this calendar because of missing VEVENT support");
+										continue;
+									}
+								}
+								ServerInfo.ResourceInfo info = new ServerInfo.ResourceInfo(
+									ServerInfo.ResourceInfo.Type.CALENDAR,
+									resource.isReadOnly(),
+									resource.getLocation().toString(),
+									resource.getDisplayName(),
+									resource.getDescription(), resource.getColor()
+								);
+								info.setTimezone(resource.getTimezone());
+								calendars.add(info);
+							}
+					serverInfo.setCalendars(calendars);
+				} else
+					Log.w(TAG, "Found calendar home set, but it doesn't advertise CalDAV support");
+			}
+		}
+						
+		if (!serverInfo.isCalDAV() && !serverInfo.isCardDAV())
+			throw new DavIncapableException(context.getString(R.string.setup_neither_caldav_nor_carddav));
+
+	}
+	
+	
+	/**
+	 * Finds the initial service URL from a given base URI (HTTP[S] or mailto URI, user name, password)
+	 * @param serverInfo	User-given service information (including base URI, i.e. HTTP[S] URL+user name+password or mailto URI and password)
+	 * @param serviceName	Service name ("carddav" or "caldav")
+	 * @return				Initial service URL (HTTP/HTTPS), without user credentials
+	 * @throws URISyntaxException when the user-given URI is invalid
+	 * @throws MalformedURLException when the user-given URI is invalid
+	 */
+	public URI getInitialContextURL(ServerInfo serverInfo, String serviceName) throws URISyntaxException, MalformedURLException {
+		String	scheme = null,
+				domain = null;
+		int		port = -1;
+		String	path = "/";
+		
+		URI baseURI = serverInfo.getBaseURI();
+		if ("mailto".equalsIgnoreCase(baseURI.getScheme())) {
+			// mailto URIs
+			String mailbox = serverInfo.getBaseURI().getSchemeSpecificPart();
+
+			// determine service FQDN
+			int pos = mailbox.lastIndexOf("@");
+			if (pos == -1)
+				throw new URISyntaxException(mailbox, "Missing @ sign");
+			
+			scheme = "https";
+			domain = mailbox.substring(pos + 1);
+			if (domain.isEmpty())
+				throw new URISyntaxException(mailbox, "Missing domain name");
+		} else {
+			// HTTP(S) URLs
+			scheme = baseURI.getScheme();
+			domain = baseURI.getHost();
+			port = baseURI.getPort();
+			path = baseURI.getPath();
+		}
+
+		// try to determine FQDN and port number using SRV records
+		try {
+			String name = "_" + serviceName + "s._tcp." + domain;
+			Log.d(TAG, "Looking up SRV records for " + name);
+			Record[] records = new Lookup(name, Type.SRV).run();
+			if (records != null && records.length >= 1) {
+				SRVRecord srv = selectSRVRecord(records);
+				
+				scheme = "https";
+				domain = srv.getTarget().toString(true);
+				port = srv.getPort();
+				Log.d(TAG, "Found " + serviceName + "s service for " + domain + " -> " + domain + ":" + port);
+				
+				if (port == 443)	// no reason to explicitly give the default port
+					port = -1;
+
+				// SRV record found, look for TXT record too (for initial context path)
+				records = new Lookup(name, Type.TXT).run();
+				if (records != null && records.length >= 1) {
+					TXTRecord txt = (TXTRecord)records[0];
+					for (Object o : txt.getStrings().toArray()) {
+						String segment = (String)o;
+						if (segment.startsWith("path=")) {
+							path = segment.substring(5);
+							Log.d(TAG, "Found initial context path for " + serviceName + " at " + domain + " -> " + path);
+							break;
+						}
+					}
+				}
+			}
+		} catch (TextParseException e) {
+			throw new URISyntaxException(domain, "Invalid domain name");
+		}
+		
+		return new URI(scheme, null, domain, port, path, null, null);
+	}
+	
+	
+	/**
+	 * Detects the current-user-principal for a given WebDavResource. At first, /.well-known/ is tried. Only
+	 * if no current-user-principal can be detected for the .well-known location, the given location of the resource
+	 * is tried.
+	 * @param resource 		Location that will be queried
+	 * @param serviceName	Well-known service name ("carddav", "caldav")
+	 * @return	WebDavResource of current-user-principal for the given service, or null if it can't be found
+	 * 
+	 * TODO: If a TXT record is given, always use it instead of trying .well-known first
+	 */
+	WebDavResource getCurrentUserPrincipal(ServerInfo serverInfo, String serviceName) throws URISyntaxException, IOException, NotAuthorizedException {
+		URI initialURL = getInitialContextURL(serverInfo, serviceName);
+		if (initialURL != null) {
+			// determine base URL (host name and initial context path)
+			WebDavResource base = new WebDavResource(httpClient,
+					initialURL,
+					serverInfo.getUserName(), serverInfo.getPassword(), serverInfo.isAuthPreemptive());
+			
+			// look for well-known service (RFC 5785)
+			try {
+				WebDavResource wellKnown = new WebDavResource(base, "/.well-known/" + serviceName);
+				wellKnown.propfind(Mode.CURRENT_USER_PRINCIPAL);
+				if (wellKnown.getCurrentUserPrincipal() != null)
+					return new WebDavResource(wellKnown, wellKnown.getCurrentUserPrincipal());
+			} catch (NotAuthorizedException e) {
+				Log.w(TAG, "Not authorized for well-known " + serviceName + " service detection", e);
+				throw e;
+			} catch (URISyntaxException e) {
+				Log.w(TAG, "Well-known" + serviceName + " service detection failed because of invalid URIs", e);
+			} catch (HttpException e) {
+				Log.d(TAG, "Well-known " + serviceName + " service detection failed with HTTP error", e);
+			} catch (DavException e) {
+				Log.w(TAG, "Well-known " + serviceName + " service detection failed with unexpected DAV response", e);
+			}
+	
+			// fall back to user-given initial context path
+			try {
+				base.propfind(Mode.CURRENT_USER_PRINCIPAL);
+				if (base.getCurrentUserPrincipal() != null)
+					return new WebDavResource(base, base.getCurrentUserPrincipal());
+			} catch (NotAuthorizedException e) {
+				Log.e(TAG, "Not authorized for querying principal", e);
+				throw e;
+			} catch (HttpException e) {
+				Log.e(TAG, "HTTP error when querying principal", e);
+			} catch (DavException e) {
+				Log.e(TAG, "DAV error when querying principal", e);
+			}
+			Log.i(TAG, "Couldn't find current-user-principal for service " + serviceName);
+		}
+		return null;
+	}
+	
+	public static boolean checkHomesetCapabilities(WebDavResource resource, String davCapability) throws URISyntaxException, IOException {
+		// check for necessary capabilities
+		try {
+			resource.options();
+			if (resource.supportsDAV(davCapability) &&
+				resource.supportsMethod("PROPFIND"))		// check only for methods that MUST be available for home sets
+				return true;
+		} catch(HttpException e) {
+			// for instance, 405 Method not allowed
+		}
+		return false;
+	}
+	
+	
+	SRVRecord selectSRVRecord(Record[] records) {
+		if (records.length > 1)
+			Log.w(TAG, "Multiple SRV records not supported yet; using first one");
+		return (SRVRecord)records[0];
+	}
+
+}

app/src/main/java/at/bitfire/davdroid/resource/Event.java

@@ -0,0 +1,368 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.resource;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.StringReader;
+import java.util.Calendar;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.SimpleTimeZone;
+import java.util.TimeZone;
+
+import lombok.Getter;
+import lombok.NonNull;
+import lombok.Setter;
+import net.fortuna.ical4j.data.CalendarBuilder;
+import net.fortuna.ical4j.data.CalendarOutputter;
+import net.fortuna.ical4j.data.ParserException;
+import net.fortuna.ical4j.model.Component;
+import net.fortuna.ical4j.model.ComponentList;
+import net.fortuna.ical4j.model.Date;
+import net.fortuna.ical4j.model.DateTime;
+import net.fortuna.ical4j.model.DefaultTimeZoneRegistryFactory;
+import net.fortuna.ical4j.model.Property;
+import net.fortuna.ical4j.model.PropertyList;
+import net.fortuna.ical4j.model.TimeZoneRegistry;
+import net.fortuna.ical4j.model.ValidationException;
+import net.fortuna.ical4j.model.component.VAlarm;
+import net.fortuna.ical4j.model.component.VEvent;
+import net.fortuna.ical4j.model.component.VTimeZone;
+import net.fortuna.ical4j.model.parameter.Value;
+import net.fortuna.ical4j.model.property.Attendee;
+import net.fortuna.ical4j.model.property.Clazz;
+import net.fortuna.ical4j.model.property.DateProperty;
+import net.fortuna.ical4j.model.property.Description;
+import net.fortuna.ical4j.model.property.DtEnd;
+import net.fortuna.ical4j.model.property.DtStart;
+import net.fortuna.ical4j.model.property.Duration;
+import net.fortuna.ical4j.model.property.ExDate;
+import net.fortuna.ical4j.model.property.ExRule;
+import net.fortuna.ical4j.model.property.LastModified;
+import net.fortuna.ical4j.model.property.Location;
+import net.fortuna.ical4j.model.property.Organizer;
+import net.fortuna.ical4j.model.property.ProdId;
+import net.fortuna.ical4j.model.property.RDate;
+import net.fortuna.ical4j.model.property.RRule;
+import net.fortuna.ical4j.model.property.Status;
+import net.fortuna.ical4j.model.property.Summary;
+import net.fortuna.ical4j.model.property.Transp;
+import net.fortuna.ical4j.model.property.Uid;
+import net.fortuna.ical4j.model.property.Version;
+import net.fortuna.ical4j.util.SimpleHostInfo;
+import net.fortuna.ical4j.util.UidGenerator;
+import android.text.format.Time;
+import android.util.Log;
+import at.bitfire.davdroid.Constants;
+import at.bitfire.davdroid.syncadapter.DavSyncAdapter;
+
+
+public class Event extends Resource {
+	private final static String TAG = "davdroid.Event";
+	
+	public final static String MIME_TYPE = "text/calendar";
+	
+	private final static TimeZoneRegistry tzRegistry = new DefaultTimeZoneRegistryFactory().createRegistry();
+	
+	@Getter @Setter private String summary, location, description;
+	
+	@Getter private DtStart dtStart;
+	@Getter private DtEnd dtEnd;
+	@Getter @Setter private Duration duration;
+	@Getter @Setter private RDate rdate;
+	@Getter @Setter private RRule rrule;
+	@Getter @Setter private ExDate exdate;
+	@Getter @Setter private ExRule exrule;
+	
+	@Getter @Setter private Boolean forPublic;
+	@Getter @Setter private Status status;
+	
+	@Getter @Setter private boolean opaque;	
+	
+	@Getter @Setter private Organizer organizer;
+	@Getter private List<Attendee> attendees = new LinkedList<Attendee>();
+	public void addAttendee(Attendee attendee) {
+		attendees.add(attendee);
+	}
+	
+	@Getter private List<VAlarm> alarms = new LinkedList<VAlarm>();
+	public void addAlarm(VAlarm alarm) {
+		alarms.add(alarm);
+	}
+	
+
+	public Event(String name, String ETag) {
+		super(name, ETag);
+	}
+	
+	public Event(long localID, String name, String ETag) {
+		super(localID, name, ETag);
+	}
+
+	
+	@Override
+	public void initialize() {
+		generateUID();
+		name = uid.replace("@", "_") + ".ics";
+	}
+	
+	protected void generateUID() {
+		UidGenerator generator = new UidGenerator(new SimpleHostInfo(DavSyncAdapter.getAndroidID()), String.valueOf(android.os.Process.myPid()));
+		uid = generator.generateUid().getValue();
+	}
+
+
+	@Override
+	@SuppressWarnings("unchecked")
+	public void parseEntity(@NonNull InputStream entity) throws IOException, InvalidResourceException {
+		net.fortuna.ical4j.model.Calendar ical;
+		try {
+			CalendarBuilder builder = new CalendarBuilder();
+			ical = builder.build(entity);
+
+			if (ical == null)
+				throw new InvalidResourceException("No iCalendar found");
+		} catch (ParserException e) {
+			throw new InvalidResourceException(e);
+		}
+		
+		// event
+		ComponentList events = ical.getComponents(Component.VEVENT);
+		if (events == null || events.isEmpty())
+			throw new InvalidResourceException("No VEVENT found");
+		VEvent event = (VEvent)events.get(0);
+		
+		if (event.getUid() != null)
+			uid = event.getUid().getValue();
+		else {
+			Log.w(TAG, "Received VEVENT without UID, generating new one");
+			generateUID();
+		}
+		
+		if ((dtStart = event.getStartDate()) == null || (dtEnd = event.getEndDate()) == null)
+			throw new InvalidResourceException("Invalid start time/end time/duration");
+
+		if (hasTime(dtStart)) {
+			validateTimeZone(dtStart);
+			validateTimeZone(dtEnd);
+		}
+		
+		// all-day events and "events on that day":
+		// * related UNIX times must be in UTC
+		// * must have a duration (set to one day if missing)
+		if (!hasTime(dtStart) && !dtEnd.getDate().after(dtStart.getDate())) {
+			Log.i(TAG, "Repairing iCal: DTEND := DTSTART+1");
+			Calendar c = Calendar.getInstance(TimeZone.getTimeZone(Time.TIMEZONE_UTC));
+			c.setTime(dtStart.getDate());
+			c.add(Calendar.DATE, 1);
+			dtEnd.setDate(new Date(c.getTimeInMillis()));
+		}
+		
+		rrule = (RRule)event.getProperty(Property.RRULE);
+		rdate = (RDate)event.getProperty(Property.RDATE);
+		exrule = (ExRule)event.getProperty(Property.EXRULE);
+		exdate = (ExDate)event.getProperty(Property.EXDATE);
+		
+		if (event.getSummary() != null)
+			summary = event.getSummary().getValue();
+		if (event.getLocation() != null)
+			location = event.getLocation().getValue();
+		if (event.getDescription() != null)
+			description = event.getDescription().getValue();
+		
+		status = event.getStatus();
+		
+		opaque = true;
+		if (event.getTransparency() == Transp.TRANSPARENT)
+			opaque = false;
+		
+		organizer = event.getOrganizer();
+		for (Object o : event.getProperties(Property.ATTENDEE))
+			attendees.add((Attendee)o);
+		
+		Clazz classification = event.getClassification();
+		if (classification != null) {
+			if (classification == Clazz.PUBLIC)
+				forPublic = true;
+			else if (classification == Clazz.CONFIDENTIAL || classification == Clazz.PRIVATE)
+				forPublic = false;
+		}
+		
+		this.alarms = event.getAlarms();
+	}
+
+	@Override
+	@SuppressWarnings("unchecked")
+	public ByteArrayOutputStream toEntity() throws IOException {
+		net.fortuna.ical4j.model.Calendar ical = new net.fortuna.ical4j.model.Calendar();
+		ical.getProperties().add(Version.VERSION_2_0);
+		ical.getProperties().add(new ProdId("-//bitfire web engineering//DAVdroid " + Constants.APP_VERSION + " (ical4j 1.0.x)//EN"));
+		
+		VEvent event = new VEvent();
+		PropertyList props = event.getProperties();
+		
+		if (uid != null)
+			props.add(new Uid(uid));
+		
+		props.add(dtStart);
+		if (dtEnd != null)
+			props.add(dtEnd);
+		if (duration != null)
+			props.add(duration);
+		
+		if (rrule != null)
+			props.add(rrule);
+		if (rdate != null)
+			props.add(rdate);
+		if (exrule != null)
+			props.add(exrule);
+		if (exdate != null)
+			props.add(exdate);
+		
+		if (summary != null && !summary.isEmpty())
+			props.add(new Summary(summary));
+		if (location != null && !location.isEmpty())
+			props.add(new Location(location));
+		if (description != null && !description.isEmpty())
+			props.add(new Description(description));
+		
+		if (status != null)
+			props.add(status);
+		if (!opaque)
+			props.add(Transp.TRANSPARENT);
+		
+		if (organizer != null)
+			props.add(organizer);
+		props.addAll(attendees);
+		
+		if (forPublic != null)
+			event.getProperties().add(forPublic ? Clazz.PUBLIC : Clazz.PRIVATE);
+		
+		event.getAlarms().addAll(alarms);
+		
+		props.add(new LastModified());
+		ical.getComponents().add(event);
+
+		// add VTIMEZONE components
+		net.fortuna.ical4j.model.TimeZone
+			tzStart = (dtStart == null ? null : dtStart.getTimeZone()),
+			tzEnd = (dtEnd == null ? null : dtEnd.getTimeZone());
+		if (tzStart != null)
+			ical.getComponents().add(tzStart.getVTimeZone());
+		if (tzEnd != null && tzEnd != tzStart)
+			ical.getComponents().add(tzEnd.getVTimeZone());
+
+		CalendarOutputter output = new CalendarOutputter(false);
+		ByteArrayOutputStream os = new ByteArrayOutputStream();
+		try {
+			output.output(ical, os);
+		} catch (ValidationException e) {
+			Log.e(TAG, "Generated invalid iCalendar");
+		}
+		return os;
+	}
+
+	
+	public long getDtStartInMillis() {
+		return dtStart.getDate().getTime();
+	}
+	
+	public String getDtStartTzID() {
+		return getTzId(dtStart);
+	}
+	
+	public void setDtStart(long tsStart, String tzID) {
+		if (tzID == null) { 	// all-day
+			dtStart = new DtStart(new Date(tsStart));
+		} else {
+			DateTime start = new DateTime(tsStart);
+			start.setTimeZone(tzRegistry.getTimeZone(tzID));
+			dtStart = new DtStart(start);
+		}
+	}
+	
+	
+	public long getDtEndInMillis() {
+		return dtEnd.getDate().getTime();
+	}
+	
+	public String getDtEndTzID() {
+		return getTzId(dtEnd);
+	}
+	
+	public void setDtEnd(long tsEnd, String tzID) {
+		if (tzID == null) { 	// all-day
+			dtEnd = new DtEnd(new Date(tsEnd));
+		} else {
+			DateTime end = new DateTime(tsEnd);
+			end.setTimeZone(tzRegistry.getTimeZone(tzID));
+			dtEnd = new DtEnd(end);
+		}
+	}
+	
+	
+	// helpers
+	
+	public boolean isAllDay() {
+		return !hasTime(dtStart);
+	}
+
+	protected static boolean hasTime(DateProperty date) {
+		return date.getDate() instanceof DateTime;
+	}
+
+	protected static String getTzId(DateProperty date) {
+		if (date.isUtc() || !hasTime(date))
+			return Time.TIMEZONE_UTC;
+		else if (date.getTimeZone() != null)
+			return date.getTimeZone().getID();
+		else if (date.getParameter(Value.TZID) != null)
+			return date.getParameter(Value.TZID).getValue();
+		
+		// fallback
+		return Time.TIMEZONE_UTC;
+	}
+
+	/* guess matching Android timezone ID */
+	protected static void validateTimeZone(DateProperty date) {
+		if (date.isUtc() || !hasTime(date))
+			return;
+		
+		String tzID = getTzId(date);
+		if (tzID == null)
+			return;
+		
+		String localTZ = Time.TIMEZONE_UTC;
+		
+		String availableTZs[] = SimpleTimeZone.getAvailableIDs();
+		for (String availableTZ : availableTZs)
+			if (tzID.indexOf(availableTZ, 0) != -1) {
+				localTZ = availableTZ;
+				break;
+			}
+		
+		Log.d(TAG, "Assuming time zone " + localTZ + " for " + tzID);
+		date.setTimeZone(tzRegistry.getTimeZone(localTZ));
+	}
+
+	public static String TimezoneDefToTzId(String timezoneDef) throws IllegalArgumentException {
+		try {
+			if (timezoneDef != null) {
+				CalendarBuilder builder = new CalendarBuilder();
+				net.fortuna.ical4j.model.Calendar cal = builder.build(new StringReader(timezoneDef));
+				VTimeZone timezone = (VTimeZone)cal.getComponent(VTimeZone.VTIMEZONE);
+				return timezone.getTimeZoneId().getValue();
+			}
+		} catch (Exception ex) {
+			Log.w(TAG, "Can't understand time zone definition, ignoring", ex);
+		}
+		throw new IllegalArgumentException();
+	}
+}

app/src/main/java/at/bitfire/davdroid/resource/InvalidResourceException.java

@@ -0,0 +1,20 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.resource;
+
+public class InvalidResourceException extends Exception {
+	private static final long serialVersionUID = 1593585432655578220L;
+	
+	public InvalidResourceException(String message) {
+		super(message);
+	}
+
+	public InvalidResourceException(Throwable throwable) {
+		super(throwable);
+	}
+}

app/src/main/java/at/bitfire/davdroid/resource/LocalCalendar.java

@@ -0,0 +1,612 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.resource;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.text.ParseException;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import lombok.Cleanup;
+import lombok.Getter;
+import net.fortuna.ical4j.model.Dur;
+import net.fortuna.ical4j.model.Parameter;
+import net.fortuna.ical4j.model.ParameterList;
+import net.fortuna.ical4j.model.PropertyList;
+import net.fortuna.ical4j.model.component.VAlarm;
+import net.fortuna.ical4j.model.parameter.Cn;
+import net.fortuna.ical4j.model.parameter.CuType;
+import net.fortuna.ical4j.model.parameter.PartStat;
+import net.fortuna.ical4j.model.parameter.Role;
+import net.fortuna.ical4j.model.property.Action;
+import net.fortuna.ical4j.model.property.Attendee;
+import net.fortuna.ical4j.model.property.Description;
+import net.fortuna.ical4j.model.property.Duration;
+import net.fortuna.ical4j.model.property.ExDate;
+import net.fortuna.ical4j.model.property.ExRule;
+import net.fortuna.ical4j.model.property.Organizer;
+import net.fortuna.ical4j.model.property.RDate;
+import net.fortuna.ical4j.model.property.RRule;
+import net.fortuna.ical4j.model.property.Status;
+
+import org.apache.commons.lang.StringUtils;
+
+import android.accounts.Account;
+import android.annotation.SuppressLint;
+import android.annotation.TargetApi;
+import android.content.ContentProviderClient;
+import android.content.ContentProviderOperation;
+import android.content.ContentProviderOperation.Builder;
+import android.content.ContentResolver;
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.database.Cursor;
+import android.database.DatabaseUtils;
+import android.net.Uri;
+import android.os.Build;
+import android.os.RemoteException;
+import android.provider.CalendarContract;
+import android.provider.CalendarContract.Attendees;
+import android.provider.CalendarContract.Calendars;
+import android.provider.CalendarContract.Events;
+import android.provider.CalendarContract.Reminders;
+import android.provider.ContactsContract;
+import android.util.Log;
+
+/**
+ * Represents a locally stored calendar, containing Events.
+ * Communicates with the Android Contacts Provider which uses an SQLite
+ * database to store the contacts.
+ */
+public class LocalCalendar extends LocalCollection<Event> {
+	private static final String TAG = "davdroid.LocalCalendar";
+
+	@Getter protected long id;
+	@Getter protected String url;
+	
+	protected static String COLLECTION_COLUMN_CTAG = Calendars.CAL_SYNC1;
+
+	
+	/* database fields */
+	
+	@Override
+	protected Uri entriesURI() {
+		return syncAdapterURI(Events.CONTENT_URI);
+	}
+
+	protected String entryColumnAccountType()	{ return Events.ACCOUNT_TYPE; }
+	protected String entryColumnAccountName()	{ return Events.ACCOUNT_NAME; }
+	
+	protected String entryColumnParentID()		{ return Events.CALENDAR_ID; }
+	protected String entryColumnID()			{ return Events._ID; }
+	protected String entryColumnRemoteName()	{ return Events._SYNC_ID; }
+	protected String entryColumnETag()			{ return Events.SYNC_DATA1; }
+
+	protected String entryColumnDirty()			{ return Events.DIRTY; }
+	protected String entryColumnDeleted()		{ return Events.DELETED; }
+	
+	@TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
+	protected String entryColumnUID() {
+		return (android.os.Build.VERSION.SDK_INT >= 17) ?
+			Events.UID_2445 : Events.SYNC_DATA2;
+	}
+
+	
+	/* class methods, constructor */
+
+	@SuppressLint("InlinedApi")
+	public static void create(Account account, ContentResolver resolver, ServerInfo.ResourceInfo info) throws LocalStorageException {
+		ContentProviderClient client = resolver.acquireContentProviderClient(CalendarContract.AUTHORITY);
+		if (client == null)
+			throw new LocalStorageException("No Calendar Provider found (Calendar app disabled?)");
+		
+		int color = 0xFFC3EA6E;		// fallback: "DAVdroid green"
+		if (info.getColor() != null) {
+			Pattern p = Pattern.compile("#?(\\p{XDigit}{6})(\\p{XDigit}{2})?");
+			Matcher m = p.matcher(info.getColor());
+			if (m.find()) {
+				int color_rgb = Integer.parseInt(m.group(1), 16);
+				int color_alpha = m.group(2) != null ? (Integer.parseInt(m.group(2), 16) & 0xFF) : 0xFF;
+				color = (color_alpha << 24) | color_rgb;
+			}
+		}
+		
+		ContentValues values = new ContentValues();
+		values.put(Calendars.ACCOUNT_NAME, account.name);
+		values.put(Calendars.ACCOUNT_TYPE, account.type);
+		values.put(Calendars.NAME, info.getURL());
+		values.put(Calendars.CALENDAR_DISPLAY_NAME, info.getTitle());
+		values.put(Calendars.CALENDAR_COLOR, color);
+		values.put(Calendars.OWNER_ACCOUNT, account.name);
+		values.put(Calendars.SYNC_EVENTS, 1);
+		values.put(Calendars.VISIBLE, 1);
+		values.put(Calendars.ALLOWED_REMINDERS, Reminders.METHOD_ALERT);
+		
+		if (info.isReadOnly())
+			values.put(Calendars.CALENDAR_ACCESS_LEVEL, Calendars.CAL_ACCESS_READ);
+		else {
+			values.put(Calendars.CALENDAR_ACCESS_LEVEL, Calendars.CAL_ACCESS_OWNER);
+			values.put(Calendars.CAN_ORGANIZER_RESPOND, 1);
+			values.put(Calendars.CAN_MODIFY_TIME_ZONE, 1);
+		}
+		
+		if (android.os.Build.VERSION.SDK_INT >= 15) {
+			values.put(Calendars.ALLOWED_AVAILABILITY, Events.AVAILABILITY_BUSY + "," + Events.AVAILABILITY_FREE + "," + Events.AVAILABILITY_TENTATIVE);
+			values.put(Calendars.ALLOWED_ATTENDEE_TYPES, Attendees.TYPE_NONE + "," + Attendees.TYPE_OPTIONAL + "," + Attendees.TYPE_REQUIRED + "," + Attendees.TYPE_RESOURCE);
+		}
+		
+		if (info.getTimezone() != null)
+			values.put(Calendars.CALENDAR_TIME_ZONE, info.getTimezone());
+		
+		Log.i(TAG, "Inserting calendar: " + values.toString() + " -> " + calendarsURI(account).toString());
+		try {
+			client.insert(calendarsURI(account), values);
+		} catch(RemoteException e) {
+			throw new LocalStorageException(e);
+		}
+	}
+	
+	public static LocalCalendar[] findAll(Account account, ContentProviderClient providerClient) throws RemoteException {
+		@Cleanup Cursor cursor = providerClient.query(calendarsURI(account),
+				new String[] { Calendars._ID, Calendars.NAME },
+				Calendars.DELETED + "=0 AND " + Calendars.SYNC_EVENTS + "=1", null, null);
+		
+		LinkedList<LocalCalendar> calendars = new LinkedList<LocalCalendar>();
+		while (cursor != null && cursor.moveToNext())
+			calendars.add(new LocalCalendar(account, providerClient, cursor.getInt(0), cursor.getString(1)));
+		return calendars.toArray(new LocalCalendar[0]);
+	}
+
+	public LocalCalendar(Account account, ContentProviderClient providerClient, long id, String url) throws RemoteException {
+		super(account, providerClient);
+		this.id = id;
+		this.url = url;
+	}
+
+	
+	/* collection operations */
+	
+	@Override
+	public String getCTag() throws LocalStorageException {
+		try {
+			@Cleanup Cursor c = providerClient.query(ContentUris.withAppendedId(calendarsURI(), id),
+					new String[] { COLLECTION_COLUMN_CTAG }, null, null, null);
+			if (c.moveToFirst()) {
+				return c.getString(0);
+			} else
+				throw new LocalStorageException("Couldn't query calendar CTag");
+		} catch(RemoteException e) {
+			throw new LocalStorageException(e);
+		}
+	}
+	
+	@Override
+	public void setCTag(String cTag) throws LocalStorageException {
+		ContentValues values = new ContentValues(1);
+		values.put(COLLECTION_COLUMN_CTAG, cTag);
+		try {
+			providerClient.update(ContentUris.withAppendedId(calendarsURI(), id), values, null, null);
+		} catch(RemoteException e) {
+			throw new LocalStorageException(e);
+		}
+	}
+
+
+	/* create/update/delete */
+	
+	public Event newResource(long localID, String resourceName, String eTag) {
+		return new Event(localID, resourceName, eTag);
+	}
+	
+	public void deleteAllExceptRemoteNames(Resource[] remoteResources) {
+		String where;
+		
+		if (remoteResources.length != 0) {
+			List<String> sqlFileNames = new LinkedList<String>();
+			for (Resource res : remoteResources)
+				sqlFileNames.add(DatabaseUtils.sqlEscapeString(res.getName()));
+			where = entryColumnRemoteName() + " NOT IN (" + StringUtils.join(sqlFileNames, ",") + ")";
+		} else
+			where = entryColumnRemoteName() + " IS NOT NULL";
+		
+		Builder builder = ContentProviderOperation.newDelete(entriesURI())
+				.withSelection(entryColumnParentID() + "=? AND (" + where + ")", new String[] { String.valueOf(id) });
+		pendingOperations.add(builder
+				.withYieldAllowed(true)
+				.build());
+	}
+	
+	
+	/* methods for populating the data object from the content provider */
+	
+
+	@Override
+	public void populate(Resource resource) throws LocalStorageException {
+		Event e = (Event)resource;
+		
+		try {
+			@Cleanup Cursor cursor = providerClient.query(ContentUris.withAppendedId(entriesURI(), e.getLocalID()),
+				new String[] {
+					/*  0 */ Events.TITLE, Events.EVENT_LOCATION, Events.DESCRIPTION,
+					/*  3 */ Events.DTSTART, Events.DTEND, Events.EVENT_TIMEZONE, Events.EVENT_END_TIMEZONE, Events.ALL_DAY,
+					/*  8 */ Events.STATUS, Events.ACCESS_LEVEL,
+					/* 10 */ Events.RRULE, Events.RDATE, Events.EXRULE, Events.EXDATE,
+					/* 14 */ Events.HAS_ATTENDEE_DATA, Events.ORGANIZER, Events.SELF_ATTENDEE_STATUS,
+					/* 17 */ entryColumnUID(), Events.DURATION, Events.AVAILABILITY
+				}, null, null, null);
+			if (cursor != null && cursor.moveToNext()) {
+				e.setUid(cursor.getString(17));
+				
+				e.setSummary(cursor.getString(0));
+				e.setLocation(cursor.getString(1));
+				e.setDescription(cursor.getString(2));
+				
+				boolean allDay = cursor.getInt(7) != 0;
+				long tsStart = cursor.getLong(3),
+					 tsEnd = cursor.getLong(4);
+				String duration = cursor.getString(18);
+				
+				String tzId = null;
+				if (allDay) {
+					e.setDtStart(tsStart, null);
+					// provide only DTEND and not DURATION for all-day events
+					if (tsEnd == 0) {
+						Dur dur = new Dur(duration);
+						java.util.Date dEnd = dur.getTime(new java.util.Date(tsStart));
+						tsEnd = dEnd.getTime();
+					}
+					e.setDtEnd(tsEnd, null);
+					
+				} else {
+					// use the start time zone for the end time, too
+					// because apps like Samsung Planner allow the user to change "the" time zone but change the start time zone only
+					tzId = cursor.getString(5);
+					e.setDtStart(tsStart, tzId);
+					if (tsEnd != 0)
+						e.setDtEnd(tsEnd, tzId);
+					else if (!StringUtils.isEmpty(duration))
+						e.setDuration(new Duration(new Dur(duration)));
+				}
+					
+				// recurrence
+				try {
+					String strRRule = cursor.getString(10);
+					if (!StringUtils.isEmpty(strRRule))
+						e.setRrule(new RRule(strRRule));
+					
+					String strRDate = cursor.getString(11);
+					if (!StringUtils.isEmpty(strRDate)) {
+						RDate rDate = new RDate();
+						rDate.setValue(strRDate);
+						e.setRdate(rDate);
+					}
+				
+					String strExRule = cursor.getString(12);
+					if (!StringUtils.isEmpty(strExRule)) {
+						ExRule exRule = new ExRule();
+						exRule.setValue(strExRule);
+						e.setExrule(exRule);
+					}
+					
+					String strExDate = cursor.getString(13);
+					if (!StringUtils.isEmpty(strExDate)) {
+						// ignored, see https://code.google.com/p/android/issues/detail?id=21426
+						ExDate exDate = new ExDate();
+						exDate.setValue(strExDate);
+						e.setExdate(exDate);
+					}
+				} catch (ParseException ex) {
+					Log.w(TAG, "Couldn't parse recurrence rules, ignoring", ex);
+				} catch (IllegalArgumentException ex) {
+					Log.w(TAG, "Invalid recurrence rules, ignoring", ex);
+				}
+	
+				// status
+				switch (cursor.getInt(8)) {
+				case Events.STATUS_CONFIRMED:
+					e.setStatus(Status.VEVENT_CONFIRMED);
+					break;
+				case Events.STATUS_TENTATIVE:
+					e.setStatus(Status.VEVENT_TENTATIVE);
+					break;
+				case Events.STATUS_CANCELED:
+					e.setStatus(Status.VEVENT_CANCELLED);
+				}
+				
+				// availability
+				e.setOpaque(cursor.getInt(19) != Events.AVAILABILITY_FREE);
+					
+				// attendees
+				if (cursor.getInt(14) != 0) {	// has attendees
+					try {
+						e.setOrganizer(new Organizer(new URI("mailto", cursor.getString(15), null)));
+					} catch (URISyntaxException ex) {
+						Log.e(TAG, "Error when creating ORGANIZER URI, ignoring", ex);
+					}
+					populateAttendees(e);
+				}
+				
+				// classification
+				switch (cursor.getInt(9)) {
+				case Events.ACCESS_CONFIDENTIAL:
+				case Events.ACCESS_PRIVATE:
+					e.setForPublic(false);
+					break;
+				case Events.ACCESS_PUBLIC:
+					e.setForPublic(true);
+				}
+				
+				populateReminders(e);
+			} else
+				throw new RecordNotFoundException();
+		} catch(RemoteException ex) {
+			throw new LocalStorageException(ex);
+		}
+	}
+
+	
+	void populateAttendees(Event e) throws RemoteException {
+		Uri attendeesUri = Attendees.CONTENT_URI.buildUpon()
+				.appendQueryParameter(ContactsContract.CALLER_IS_SYNCADAPTER, "true")
+				.build();
+		@Cleanup Cursor c = providerClient.query(attendeesUri, new String[] {
+				/* 0 */ Attendees.ATTENDEE_EMAIL, Attendees.ATTENDEE_NAME, Attendees.ATTENDEE_TYPE,
+				/* 3 */ Attendees.ATTENDEE_RELATIONSHIP, Attendees.STATUS
+			}, Attendees.EVENT_ID + "=?", new String[] { String.valueOf(e.getLocalID()) }, null);
+		while (c != null && c.moveToNext()) {
+			try {
+				Attendee attendee = new Attendee(new URI("mailto", c.getString(0), null));
+				ParameterList params = attendee.getParameters();
+				
+				String cn = c.getString(1);
+				if (cn != null)
+					params.add(new Cn(cn));
+				
+				// type
+				int type = c.getInt(2);
+				params.add((type == Attendees.TYPE_RESOURCE) ? CuType.RESOURCE : CuType.INDIVIDUAL);
+				
+				// role
+				int relationship = c.getInt(3); 
+				switch (relationship) {
+				case Attendees.RELATIONSHIP_ORGANIZER:
+					params.add(Role.CHAIR);
+					break;
+				case Attendees.RELATIONSHIP_ATTENDEE:
+				case Attendees.RELATIONSHIP_PERFORMER:
+				case Attendees.RELATIONSHIP_SPEAKER:
+					params.add((type == Attendees.TYPE_REQUIRED) ? Role.REQ_PARTICIPANT : Role.OPT_PARTICIPANT);
+					break;
+				case Attendees.RELATIONSHIP_NONE:
+					params.add(Role.NON_PARTICIPANT);
+				}
+	
+				// status
+				switch (c.getInt(4)) {
+				case Attendees.ATTENDEE_STATUS_INVITED:
+					params.add(PartStat.NEEDS_ACTION);
+					break;
+				case Attendees.ATTENDEE_STATUS_ACCEPTED:
+					params.add(PartStat.ACCEPTED);
+					break;
+				case Attendees.ATTENDEE_STATUS_DECLINED:
+					params.add(PartStat.DECLINED);
+					break;
+				case Attendees.ATTENDEE_STATUS_TENTATIVE:
+					params.add(PartStat.TENTATIVE);
+					break;
+				}
+				
+				e.addAttendee(attendee);
+			} catch (URISyntaxException ex) {
+				Log.e(TAG, "Couldn't parse attendee information, ignoring", ex);
+			}
+		}
+	}
+	
+	void populateReminders(Event e) throws RemoteException {
+		// reminders
+		Uri remindersUri = Reminders.CONTENT_URI.buildUpon()
+				.appendQueryParameter(ContactsContract.CALLER_IS_SYNCADAPTER, "true")
+				.build();
+		@Cleanup Cursor c = providerClient.query(remindersUri, new String[] {
+				/* 0 */ Reminders.MINUTES, Reminders.METHOD
+			}, Reminders.EVENT_ID + "=?", new String[] { String.valueOf(e.getLocalID()) }, null);
+		while (c != null && c.moveToNext()) {
+			VAlarm alarm = new VAlarm(new Dur(0, 0, -c.getInt(0), 0));
+			
+			PropertyList props = alarm.getProperties();
+			switch (c.getInt(1)) {
+			/*case Reminders.METHOD_EMAIL:
+				props.add(Action.EMAIL);
+				break;*/
+			default:
+				props.add(Action.DISPLAY);
+				props.add(new Description(e.getSummary()));
+			}
+			e.addAlarm(alarm);
+		}
+	}
+	
+	
+	/* content builder methods */
+
+	@Override
+	protected Builder buildEntry(Builder builder, Resource resource) {
+		Event event = (Event)resource;
+
+		builder = builder
+				.withValue(Events.CALENDAR_ID, id)
+				.withValue(entryColumnRemoteName(), event.getName())
+				.withValue(entryColumnETag(), event.getETag())
+				.withValue(entryColumnUID(), event.getUid())
+				.withValue(Events.ALL_DAY, event.isAllDay() ? 1 : 0)
+				.withValue(Events.DTSTART, event.getDtStartInMillis())
+				.withValue(Events.EVENT_TIMEZONE, event.getDtStartTzID())
+				.withValue(Events.HAS_ATTENDEE_DATA, event.getAttendees().isEmpty() ? 0 : 1)
+				.withValue(Events.GUESTS_CAN_INVITE_OTHERS, 1)
+				.withValue(Events.GUESTS_CAN_MODIFY, 1)
+				.withValue(Events.GUESTS_CAN_SEE_GUESTS, 1);
+		
+		boolean recurring = false;
+		if (event.getRrule() != null) {
+			recurring = true;
+			builder = builder.withValue(Events.RRULE, event.getRrule().getValue());
+		}
+		if (event.getRdate() != null) {
+			recurring = true;
+			builder = builder.withValue(Events.RDATE, event.getRdate().getValue());
+		}
+		if (event.getExrule() != null)
+			builder = builder.withValue(Events.EXRULE, event.getExrule().getValue());
+		if (event.getExdate() != null)
+			builder = builder.withValue(Events.EXDATE, event.getExdate().getValue());
+		
+		// set either DTEND for single-time events or DURATION for recurring events
+		// because that's the way Android likes it (see docs)
+		if (recurring) {
+			// calculate DURATION from start and end date
+			Duration duration = new Duration(event.getDtStart().getDate(), event.getDtEnd().getDate());
+			builder = builder.withValue(Events.DURATION, duration.getValue());
+		} else {
+			builder = builder
+					.withValue(Events.DTEND, event.getDtEndInMillis())
+					.withValue(Events.EVENT_END_TIMEZONE, event.getDtEndTzID());
+		}
+		
+		if (event.getSummary() != null)
+			builder = builder.withValue(Events.TITLE, event.getSummary());
+		if (event.getLocation() != null)
+			builder = builder.withValue(Events.EVENT_LOCATION, event.getLocation());
+		if (event.getDescription() != null)
+			builder = builder.withValue(Events.DESCRIPTION, event.getDescription());
+		
+		if (event.getOrganizer() != null && event.getOrganizer().getCalAddress() != null) {
+			URI organizer = event.getOrganizer().getCalAddress();
+			if (organizer.getScheme() != null && organizer.getScheme().equalsIgnoreCase("mailto"))
+				builder = builder.withValue(Events.ORGANIZER, organizer.getSchemeSpecificPart());
+		}
+		
+		Status status = event.getStatus();
+		if (status != null) {
+			int statusCode = Events.STATUS_TENTATIVE;
+			if (status == Status.VEVENT_CONFIRMED)
+				statusCode = Events.STATUS_CONFIRMED;
+			else if (status == Status.VEVENT_CANCELLED)
+				statusCode = Events.STATUS_CANCELED;
+			builder = builder.withValue(Events.STATUS, statusCode);
+		}
+		
+		builder = builder.withValue(Events.AVAILABILITY, event.isOpaque() ? Events.AVAILABILITY_BUSY : Events.AVAILABILITY_FREE);
+		
+		if (event.getForPublic() != null)
+			builder = builder.withValue(Events.ACCESS_LEVEL, event.getForPublic() ? Events.ACCESS_PUBLIC : Events.ACCESS_PRIVATE);
+
+		return builder;
+	}
+
+	
+	@Override
+	protected void addDataRows(Resource resource, long localID, int backrefIdx) {
+		Event event = (Event)resource;
+		for (Attendee attendee : event.getAttendees())
+			pendingOperations.add(buildAttendee(newDataInsertBuilder(Attendees.CONTENT_URI, Attendees.EVENT_ID, localID, backrefIdx), attendee).build());
+		for (VAlarm alarm : event.getAlarms())
+			pendingOperations.add(buildReminder(newDataInsertBuilder(Reminders.CONTENT_URI, Reminders.EVENT_ID, localID, backrefIdx), alarm).build());
+	}
+	
+	@Override
+	protected void removeDataRows(Resource resource) {
+		Event event = (Event)resource;
+		pendingOperations.add(ContentProviderOperation.newDelete(syncAdapterURI(Attendees.CONTENT_URI))
+				.withSelection(Attendees.EVENT_ID + "=?",
+				new String[] { String.valueOf(event.getLocalID()) }).build());
+		pendingOperations.add(ContentProviderOperation.newDelete(syncAdapterURI(Reminders.CONTENT_URI))
+				.withSelection(Reminders.EVENT_ID + "=?",
+				new String[] { String.valueOf(event.getLocalID()) }).build());
+	}
+
+	
+	@SuppressLint("InlinedApi")
+	protected Builder buildAttendee(Builder builder, Attendee attendee) {
+		Uri member = Uri.parse(attendee.getValue());
+		String email = member.getSchemeSpecificPart();
+		
+		Cn cn = (Cn)attendee.getParameter(Parameter.CN);
+		if (cn != null)
+			builder = builder.withValue(Attendees.ATTENDEE_NAME, cn.getValue());
+		
+		int type = Attendees.TYPE_NONE;
+		
+		CuType cutype = (CuType)attendee.getParameter(Parameter.CUTYPE);
+		if (cutype == CuType.RESOURCE)
+			type = Attendees.TYPE_RESOURCE;
+		else {
+			Role role = (Role)attendee.getParameter(Parameter.ROLE);
+			int relationship;
+			if (role == Role.CHAIR)
+				relationship = Attendees.RELATIONSHIP_ORGANIZER;
+			else {
+				relationship = Attendees.RELATIONSHIP_ATTENDEE;
+				if (role == Role.OPT_PARTICIPANT)
+					type = Attendees.TYPE_OPTIONAL;
+				else if (role == Role.REQ_PARTICIPANT)
+					type = Attendees.TYPE_REQUIRED;
+			}
+			builder = builder.withValue(Attendees.ATTENDEE_RELATIONSHIP, relationship);
+		}
+		
+		int status = Attendees.ATTENDEE_STATUS_NONE;
+		PartStat partStat = (PartStat)attendee.getParameter(Parameter.PARTSTAT);
+		if (partStat == null || partStat == PartStat.NEEDS_ACTION)
+			status = Attendees.ATTENDEE_STATUS_INVITED;
+		else if (partStat == PartStat.ACCEPTED)
+			status = Attendees.ATTENDEE_STATUS_ACCEPTED;
+		else if (partStat == PartStat.DECLINED)
+			status = Attendees.ATTENDEE_STATUS_DECLINED;
+		else if (partStat == PartStat.TENTATIVE)
+			status = Attendees.ATTENDEE_STATUS_TENTATIVE;
+		
+		return builder
+			.withValue(Attendees.ATTENDEE_EMAIL, email)
+			.withValue(Attendees.ATTENDEE_TYPE, type)
+			.withValue(Attendees.ATTENDEE_STATUS, status);
+	}
+	
+	protected Builder buildReminder(Builder builder, VAlarm alarm) {
+		int minutes = 0;
+		
+		Dur duration;
+		if (alarm.getTrigger() != null && (duration = alarm.getTrigger().getDuration()) != null)
+			minutes = duration.getDays() * 24*60 + duration.getHours()*60 + duration.getMinutes();
+		
+		Log.d(TAG, "Adding alarm " + minutes + " min before");
+		
+		return builder
+				.withValue(Reminders.METHOD, Reminders.METHOD_ALERT)
+				.withValue(Reminders.MINUTES, minutes);
+	}
+	
+	
+	
+	/* private helper methods */
+	
+	protected static Uri calendarsURI(Account account) {
+		return Calendars.CONTENT_URI.buildUpon().appendQueryParameter(Calendars.ACCOUNT_NAME, account.name)
+				.appendQueryParameter(Calendars.ACCOUNT_TYPE, account.type)
+				.appendQueryParameter(CalendarContract.CALLER_IS_SYNCADAPTER, "true").build();
+	}
+
+	protected Uri calendarsURI() {
+		return calendarsURI(account);
+	}
+
+}

app/src/main/java/at/bitfire/davdroid/resource/LocalCollection.java

@@ -0,0 +1,361 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.resource;
+
+import java.util.ArrayList;
+
+import lombok.Cleanup;
+import android.accounts.Account;
+import android.content.ContentProviderClient;
+import android.content.ContentProviderOperation;
+import android.content.ContentProviderOperation.Builder;
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.content.OperationApplicationException;
+import android.database.Cursor;
+import android.net.Uri;
+import android.os.RemoteException;
+import android.provider.CalendarContract;
+import android.util.Log;
+
+/**
+ * Represents a locally-stored synchronizable collection (for instance, the
+ * address book or a calendar). Manages a CTag that stores the last known
+ * remote CTag (the remote CTag changes whenever something in the remote collection changes).
+ * 
+ * @param <T> Subtype of Resource that can be stored in the collection 
+ */
+public abstract class LocalCollection<T extends Resource> {
+	private static final String TAG = "davdroid.LocalCollection";
+	
+	protected Account account;
+	protected ContentProviderClient providerClient;
+	protected ArrayList<ContentProviderOperation> pendingOperations = new ArrayList<ContentProviderOperation>();
+
+	
+	// database fields
+	
+	/** base Uri of the collection's entries (for instance, Events.CONTENT_URI);
+	 *  apply syncAdapterURI() before returning a value */
+	abstract protected Uri entriesURI();
+
+	/** column name of the type of the account the entry belongs to */
+	abstract protected String entryColumnAccountType();
+	/** column name of the name of the account the entry belongs to */
+	abstract protected String entryColumnAccountName();
+	
+	/** column name of the collection ID the entry belongs to */
+	abstract protected String entryColumnParentID();
+	/** column name of an entry's ID */
+	abstract protected String entryColumnID();
+	/** column name of an entry's file name on the WebDAV server */
+	abstract protected String entryColumnRemoteName();
+	/** column name of an entry's last ETag on the WebDAV server; null if entry hasn't been uploaded yet */
+	abstract protected String entryColumnETag();
+	
+	/** column name of an entry's "dirty" flag (managed by content provider) */
+	abstract protected String entryColumnDirty();
+	/** column name of an entry's "deleted" flag (managed by content provider) */
+	abstract protected String entryColumnDeleted();
+	
+	/** column name of an entry's UID */
+	abstract protected String entryColumnUID();
+	
+
+	LocalCollection(Account account, ContentProviderClient providerClient) {
+		this.account = account;
+		this.providerClient = providerClient;
+	}
+	
+
+	// collection operations
+	
+	/** gets the ID if the collection (for instance, ID of the Android calendar) */
+	abstract public long getId();
+	/** gets the CTag of the collection */
+	abstract public String getCTag() throws LocalStorageException;
+	/** sets the CTag of the collection */
+	abstract public void setCTag(String cTag) throws LocalStorageException;
+
+	
+	// content provider (= database) querying
+
+	/**
+	 * Finds new resources (resources which haven't been uploaded yet).
+	 * New resources are 1) dirty, and 2) don't have an ETag yet.
+	 * 
+	 * @return IDs of new resources
+	 * @throws LocalStorageException when the content provider couldn't be queried
+	 */
+	public long[] findNew() throws LocalStorageException {
+		String where = entryColumnDirty() + "=1 AND " + entryColumnETag() + " IS NULL";
+		if (entryColumnParentID() != null)
+			where += " AND " + entryColumnParentID() + "=" + String.valueOf(getId());
+		try {
+			@Cleanup Cursor cursor = providerClient.query(entriesURI(),
+					new String[] { entryColumnID() },
+					where, null, null);
+			if (cursor == null)
+				throw new LocalStorageException("Couldn't query new records");
+			
+			long[] fresh = new long[cursor.getCount()];
+			for (int idx = 0; cursor.moveToNext(); idx++) {
+				long id = cursor.getLong(0);
+				
+				// new record: generate UID + remote file name so that we can upload
+				T resource = findById(id, false);
+				resource.initialize();
+				// write generated UID + remote file name into database
+				ContentValues values = new ContentValues(2);
+				values.put(entryColumnUID(), resource.getUid());
+				values.put(entryColumnRemoteName(), resource.getName());
+				providerClient.update(ContentUris.withAppendedId(entriesURI(), id), values, null, null);
+				
+				fresh[idx] = id;
+			}
+			return fresh;
+		} catch(RemoteException ex) {
+			throw new LocalStorageException(ex);
+		}
+	}
+	
+	/**
+	 * Finds updated resources (resources which have already been uploaded, but have changed locally).
+	 * Updated resources are 1) dirty, and 2) already have an ETag.
+	 * 
+	 * @return IDs of updated resources
+	 * @throws LocalStorageException when the content provider couldn't be queried
+	 */
+	public long[] findUpdated() throws LocalStorageException {
+		String where = entryColumnDirty() + "=1 AND " + entryColumnETag() + " IS NOT NULL";
+		if (entryColumnParentID() != null)
+			where += " AND " + entryColumnParentID() + "=" + String.valueOf(getId());
+		try {
+			@Cleanup Cursor cursor = providerClient.query(entriesURI(),
+					new String[] { entryColumnID(), entryColumnRemoteName(), entryColumnETag() },
+					where, null, null);
+			if (cursor == null)
+				throw new LocalStorageException("Couldn't query updated records");
+			
+			long[] updated = new long[cursor.getCount()];
+			for (int idx = 0; cursor.moveToNext(); idx++)
+				updated[idx] = cursor.getLong(0);
+			return updated;
+		} catch(RemoteException ex) {
+			throw new LocalStorageException(ex);
+		}
+	}
+
+	/**
+	 * Finds deleted resources (resources which have been marked for deletion).
+	 * Deleted resources have the "deleted" flag set.
+	 * 
+	 * @return IDs of deleted resources
+	 * @throws LocalStorageException when the content provider couldn't be queried
+	 */
+	public long[] findDeleted() throws LocalStorageException {
+		String where = entryColumnDeleted() + "=1";
+		if (entryColumnParentID() != null)
+			where += " AND " + entryColumnParentID() + "=" + String.valueOf(getId());
+		try {
+			@Cleanup Cursor cursor = providerClient.query(entriesURI(),
+					new String[] { entryColumnID(), entryColumnRemoteName(), entryColumnETag() },
+					where, null, null);
+			if (cursor == null)
+				throw new LocalStorageException("Couldn't query dirty records");
+			
+			long deleted[] = new long[cursor.getCount()];
+			for (int idx = 0; cursor.moveToNext(); idx++)
+				deleted[idx] = cursor.getLong(0);
+			return deleted;
+		} catch(RemoteException ex) {
+			throw new LocalStorageException(ex);
+		}
+	}
+	
+	/**
+	 * Finds a specific resource by ID.
+	 * @param localID	ID of the resource
+	 * @param populate	true: populates all data fields (for instance, contact or event details);
+	 * 					false: only remote file name and ETag are populated
+	 * @return resource with either ID/remote file/name/ETag or all fields populated
+	 * @throws RecordNotFoundException when the resource couldn't be found
+	 * @throws LocalStorageException when the content provider couldn't be queried
+	 */
+	public T findById(long localID, boolean populate) throws LocalStorageException {
+		try {
+			@Cleanup Cursor cursor = providerClient.query(ContentUris.withAppendedId(entriesURI(), localID),
+					new String[] { entryColumnRemoteName(), entryColumnETag() }, null, null, null);
+			if (cursor != null && cursor.moveToNext()) {
+				T resource = newResource(localID, cursor.getString(0), cursor.getString(1));
+				if (populate)
+					populate(resource);
+				return resource;
+			} else
+				throw new RecordNotFoundException();
+		} catch(RemoteException ex) {
+			throw new LocalStorageException(ex);
+		}
+	}
+	
+	/**
+	 * Finds a specific resource by remote file name.
+	 * @param localID	remote file name of the resource
+	 * @param populate	true: populates all data fields (for instance, contact or event details);
+	 * 					false: only remote file name and ETag are populated
+	 * @return resource with either ID/remote file/name/ETag or all fields populated
+	 * @throws RecordNotFoundException when the resource couldn't be found
+	 * @throws LocalStorageException when the content provider couldn't be queried
+	 */
+	public T findByRemoteName(String remoteName, boolean populate) throws LocalStorageException {
+		try {
+			@Cleanup Cursor cursor = providerClient.query(entriesURI(),
+					new String[] { entryColumnID(), entryColumnRemoteName(), entryColumnETag() },
+					entryColumnRemoteName() + "=?", new String[] { remoteName }, null);
+			if (cursor != null && cursor.moveToNext()) {
+				T resource = newResource(cursor.getLong(0), cursor.getString(1), cursor.getString(2));
+				if (populate)
+					populate(resource);
+				return resource;
+			} else
+				throw new RecordNotFoundException();
+		} catch(RemoteException ex) {
+			throw new LocalStorageException(ex);
+		}
+	}
+
+	/** populates all data fields from the content provider */
+	public abstract void populate(Resource record) throws LocalStorageException;
+
+	
+	// create/update/delete
+	
+	/**
+	 * Creates a new resource object in memory. No content provider operations involved.
+	 * @param localID the ID of the resource
+	 * @param resourceName the (remote) file name of the resource
+	 * @param ETag of the resource
+	 * @return the new resource object */
+	abstract public T newResource(long localID, String resourceName, String eTag);
+	
+	/** Enqueues adding the resource (including all data) to the local collection. Requires commit(). */
+	public void add(Resource resource) {
+		int idx = pendingOperations.size();
+		pendingOperations.add(
+				buildEntry(ContentProviderOperation.newInsert(entriesURI()), resource)
+				.withYieldAllowed(true)
+				.build());
+		
+		addDataRows(resource, -1, idx);
+	}
+	
+	/** Enqueues updating an existing resource in the local collection. The resource will be found by 
+	 * the remote file name and all data will be updated. Requires commit(). */
+	public void updateByRemoteName(Resource remoteResource) throws LocalStorageException {
+		T localResource = findByRemoteName(remoteResource.getName(), false);
+		pendingOperations.add(
+				buildEntry(ContentProviderOperation.newUpdate(ContentUris.withAppendedId(entriesURI(), localResource.getLocalID())), remoteResource)
+				.withValue(entryColumnETag(), remoteResource.getETag())
+				.withYieldAllowed(true)
+				.build());
+		
+		removeDataRows(localResource);
+		addDataRows(remoteResource, localResource.getLocalID(), -1);
+	}
+
+	/** Enqueues deleting a resource from the local collection. Requires commit(). */
+	public void delete(Resource resource) {
+		pendingOperations.add(ContentProviderOperation
+				.newDelete(ContentUris.withAppendedId(entriesURI(), resource.getLocalID()))
+				.withYieldAllowed(true)
+				.build());
+	}
+
+	/**
+	 * Enqueues deleting all resources except the give ones from the local collection. Requires commit().
+	 * @param remoteResources resources with these remote file names will be kept
+	 */
+	public abstract void deleteAllExceptRemoteNames(Resource[] remoteResources);
+	
+	/** Updates the locally-known ETag of a resource. */
+	public void updateETag(Resource res, String eTag) throws LocalStorageException {
+		Log.d(TAG, "Setting ETag of local resource " + res + " to " + eTag);
+		
+		ContentValues values = new ContentValues(1);
+		values.put(entryColumnETag(), eTag);
+		try {
+			providerClient.update(ContentUris.withAppendedId(entriesURI(), res.getLocalID()), values, null, new String[] {});
+		} catch (RemoteException e) {
+			throw new LocalStorageException(e);
+		}
+	}
+	
+	/** Enqueues removing the dirty flag from a locally-stored resource. Requires commit(). */
+	public void clearDirty(Resource resource) {
+		pendingOperations.add(ContentProviderOperation
+				.newUpdate(ContentUris.withAppendedId(entriesURI(), resource.getLocalID()))
+				.withValue(entryColumnDirty(), 0)
+				.build());
+	}
+
+	/** Commits enqueued operations to the content provider (for batch operations). */
+	public void commit() throws LocalStorageException {
+		if (!pendingOperations.isEmpty())
+			try {
+				Log.d(TAG, "Committing " + pendingOperations.size() + " operations");
+				providerClient.applyBatch(pendingOperations);
+				pendingOperations.clear();
+			} catch (RemoteException ex) {
+				throw new LocalStorageException(ex);
+			} catch(OperationApplicationException ex) {
+				throw new LocalStorageException(ex);
+			}
+	}
+
+	
+	// helpers
+
+	protected void queueOperation(Builder builder) {
+		if (builder != null)
+			pendingOperations.add(builder.build());
+	}
+
+	/** Appends account type, name and CALLER_IS_SYNCADAPTER to an Uri. */
+	protected Uri syncAdapterURI(Uri baseURI) {
+		return baseURI.buildUpon()
+				.appendQueryParameter(entryColumnAccountType(), account.type)
+				.appendQueryParameter(entryColumnAccountName(), account.name)
+				.appendQueryParameter(CalendarContract.CALLER_IS_SYNCADAPTER, "true")
+				.build();
+	}
+	
+	protected Builder newDataInsertBuilder(Uri dataUri, String refFieldName, long raw_ref_id, Integer backrefIdx) {
+		Builder builder = ContentProviderOperation.newInsert(syncAdapterURI(dataUri));
+		if (backrefIdx != -1)
+			return builder.withValueBackReference(refFieldName, backrefIdx);
+		else
+			return builder.withValue(refFieldName, raw_ref_id);
+	}
+	
+	
+	// content builders
+
+	/**
+	 * Builds the main entry (for instance, a ContactsContract.RawContacts row) from a resource.
+	 * The entry is built for insertion to the location identified by entriesURI().
+	 * 
+	 * @param builder Builder to be extended by all resource data that can be stored without extra data rows.
+	 */
+	protected abstract Builder buildEntry(Builder builder, Resource resource);
+	
+	/** Enqueues adding extra data rows of the resource to the local collection. */
+	protected abstract void addDataRows(Resource resource, long localID, int backrefIdx);
+	
+	/** Enqueues removing all extra data rows of the resource from the local collection. */
+	protected abstract void removeDataRows(Resource resource);
+}

app/src/main/java/at/bitfire/davdroid/resource/LocalStorageException.java

@@ -0,0 +1,31 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.resource;
+
+public class LocalStorageException extends Exception {
+	private static final long serialVersionUID = -7787658815291629529L;
+	
+	private static final String detailMessage = "Couldn't access local content provider";
+	
+
+	public LocalStorageException(String detailMessage, Throwable throwable) {
+		super(detailMessage, throwable);
+	}
+
+	public LocalStorageException(String detailMessage) {
+		super(detailMessage);
+	}
+	
+	public LocalStorageException(Throwable throwable) {
+		super(detailMessage, throwable);
+	}
+
+	public LocalStorageException() {
+		super(detailMessage);
+	}
+}

app/src/main/java/at/bitfire/davdroid/resource/RecordNotFoundException.java

@@ -0,0 +1,28 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.resource;
+
+/**
+ * Thrown when a local record (for instance, Contact with ID 12345) should be read
+ * but could not be found. 
+ */
+public class RecordNotFoundException extends LocalStorageException {
+	private static final long serialVersionUID = 4961024282198632578L;
+	
+	private static final String detailMessage = "Record not found in local content provider"; 
+	
+	
+	RecordNotFoundException(Throwable ex) {
+		super(detailMessage, ex);
+	}
+	
+	RecordNotFoundException() {
+		super(detailMessage);
+	}
+
+}

app/src/main/java/at/bitfire/davdroid/resource/RemoteCollection.java

@@ -0,0 +1,180 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.resource;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URISyntaxException;
+import java.util.LinkedList;
+import java.util.List;
+
+import lombok.Cleanup;
+import lombok.Getter;
+import net.fortuna.ical4j.model.ValidationException;
+import android.util.Log;
+import at.bitfire.davdroid.URIUtils;
+import at.bitfire.davdroid.webdav.DavException;
+import at.bitfire.davdroid.webdav.DavMultiget;
+import at.bitfire.davdroid.webdav.DavNoContentException;
+import at.bitfire.davdroid.webdav.HttpException;
+import at.bitfire.davdroid.webdav.HttpPropfind;
+import at.bitfire.davdroid.webdav.WebDavResource;
+import at.bitfire.davdroid.webdav.WebDavResource.PutMode;
+import org.apache.http.impl.client.CloseableHttpClient;
+import ezvcard.io.text.VCardParseException;
+
+/**
+ * Represents a remotely stored synchronizable collection (collection as in
+ * WebDAV terminology).
+ *
+ * @param <T> Subtype of Resource that can be stored in the collection
+ */
+public abstract class RemoteCollection<T extends Resource> {
+	private static final String TAG = "davdroid.RemoteCollection";
+	
+	CloseableHttpClient httpClient;
+	@Getter WebDavResource collection;
+
+	abstract protected String memberContentType();
+	abstract protected DavMultiget.Type multiGetType();
+	abstract protected T newResourceSkeleton(String name, String ETag);
+	
+	public RemoteCollection(CloseableHttpClient httpClient, String baseURL, String user, String password, boolean preemptiveAuth) throws URISyntaxException {
+		this.httpClient = httpClient;
+		
+		collection = new WebDavResource(httpClient, URIUtils.parseURI(baseURL), user, password, preemptiveAuth);
+	}
+
+	
+	/* collection operations */
+
+	public String getCTag() throws URISyntaxException, IOException, HttpException {
+		try {
+			if (collection.getCTag() == null && collection.getMembers() == null)	// not already fetched
+				collection.propfind(HttpPropfind.Mode.COLLECTION_CTAG);
+		} catch (DavException e) {
+			return null;
+		}
+		return collection.getCTag();
+	}
+	
+	public Resource[] getMemberETags() throws URISyntaxException, IOException, DavException, HttpException {
+		collection.propfind(HttpPropfind.Mode.MEMBERS_ETAG);
+			
+		List<T> resources = new LinkedList<T>();
+		if (collection.getMembers() != null) {
+			for (WebDavResource member : collection.getMembers())
+				resources.add(newResourceSkeleton(member.getName(), member.getETag()));
+		}
+		return resources.toArray(new Resource[0]);
+	}
+	
+	@SuppressWarnings("unchecked")
+	public Resource[] multiGet(Resource[] resources) throws URISyntaxException, IOException, DavException, HttpException {
+		try {
+			if (resources.length == 1)
+				return (T[]) new Resource[] { get(resources[0]) };
+			
+			Log.i(TAG, "Multi-getting " + resources.length + " remote resource(s)");
+			
+			LinkedList<String> names = new LinkedList<String>();
+			for (Resource resource : resources)
+				names.add(resource.getName());
+			
+			LinkedList<T> foundResources = new LinkedList<T>();
+			collection.multiGet(multiGetType(), names.toArray(new String[0]));
+			if (collection.getMembers() == null)
+				throw new DavNoContentException();
+			
+			for (WebDavResource member : collection.getMembers()) {
+				T resource = newResourceSkeleton(member.getName(), member.getETag());
+				try {
+					if (member.getContent() != null) {
+						@Cleanup InputStream is = new ByteArrayInputStream(member.getContent());
+						resource.parseEntity(is);
+						foundResources.add(resource);
+					} else
+						Log.e(TAG, "Ignoring entity without content");
+				} catch (InvalidResourceException e) {
+					Log.e(TAG, "Ignoring unparseable entity in multi-response", e);
+				}
+			}
+			
+			return foundResources.toArray(new Resource[0]);
+		} catch (InvalidResourceException e) {
+			Log.e(TAG, "Couldn't parse entity from GET", e);
+		}
+		
+		return new Resource[0];
+	}
+	
+	
+	/* internal member operations */
+
+	public Resource get(Resource resource) throws URISyntaxException, IOException, HttpException, DavException, InvalidResourceException {
+		WebDavResource member = new WebDavResource(collection, resource.getName());
+		
+		if (resource instanceof Contact)
+			member.get(Contact.MIME_TYPE);
+		else if (resource instanceof Event)
+			member.get(Event.MIME_TYPE);
+		else {
+			Log.wtf(TAG, "Should fetch something, but neither contact nor calendar");
+			throw new InvalidResourceException("Didn't now which MIME type to accept");
+		}
+		
+		byte[] data = member.getContent();
+		if (data == null)
+			throw new DavNoContentException();
+		
+		@Cleanup InputStream is = new ByteArrayInputStream(data);
+		try {
+			resource.parseEntity(is);
+		} catch(VCardParseException e) {
+			throw new InvalidResourceException(e);
+		}
+		return resource;
+	}
+	
+	// returns ETag of the created resource, if returned by server
+	public String add(Resource res) throws URISyntaxException, IOException, HttpException, ValidationException {
+		WebDavResource member = new WebDavResource(collection, res.getName(), res.getETag());
+		member.setContentType(memberContentType());
+		
+		@Cleanup ByteArrayOutputStream os = res.toEntity();
+		String eTag = member.put(os.toByteArray(), PutMode.ADD_DONT_OVERWRITE);
+		
+		// after a successful upload, the collection has implicitely changed, too
+		collection.invalidateCTag();
+		
+		return eTag;
+	}
+
+	public void delete(Resource res) throws URISyntaxException, IOException, HttpException {
+		WebDavResource member = new WebDavResource(collection, res.getName(), res.getETag());
+		member.delete();
+		
+		collection.invalidateCTag();
+	}
+	
+	// returns ETag of the updated resource, if returned by server
+	public String update(Resource res) throws URISyntaxException, IOException, HttpException, ValidationException {
+		WebDavResource member = new WebDavResource(collection, res.getName(), res.getETag());
+		member.setContentType(memberContentType());
+		
+		@Cleanup ByteArrayOutputStream os = res.toEntity();
+		String eTag = member.put(os.toByteArray(), PutMode.UPDATE_DONT_OVERWRITE);
+		
+		// after a successful upload, the collection has implicitely changed, too
+		collection.invalidateCTag();
+		
+		return eTag;
+	}
+}

app/src/main/java/at/bitfire/davdroid/resource/Resource.java

@@ -0,0 +1,46 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.resource;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+import lombok.Getter;
+import lombok.Setter;
+import lombok.ToString;
+
+/**
+ * Represents a resource that can be contained in a LocalCollection or RemoteCollection
+ * for synchronization by WebDAV.
+ */
+@ToString
+public abstract class Resource {
+	@Getter @Setter protected String name, ETag;
+	@Getter @Setter protected String uid;
+	@Getter protected long localID;
+
+	
+	public Resource(String name, String ETag) {
+		this.name = name;
+		this.ETag = ETag;
+	}
+	
+	public Resource(long localID, String name, String ETag) {
+		this(name, ETag);
+		this.localID = localID;
+	}
+	
+	/** initializes UID and remote file name (required for first upload) */
+	public abstract void initialize();
+	
+	/** fills the resource data from an input stream (for instance, .vcf file for Contact) */
+	public abstract void parseEntity(InputStream entity) throws IOException, InvalidResourceException;
+	/** writes the resource data to an output stream (for instance, .vcf file for Contact) */
+	public abstract ByteArrayOutputStream toEntity() throws IOException;
+}

app/src/main/java/at/bitfire/davdroid/resource/ServerInfo.java

@@ -0,0 +1,68 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.resource;
+
+import java.io.Serializable;
+import java.net.URI;
+import java.util.LinkedList;
+import java.util.List;
+
+import ezvcard.VCardVersion;
+import lombok.Data;
+import lombok.RequiredArgsConstructor;
+
+@RequiredArgsConstructor(suppressConstructorProperties=true)
+@Data
+public class ServerInfo implements Serializable {
+	private static final long serialVersionUID = 6744847358282980437L;
+	
+	enum Scheme {
+		HTTP, HTTPS, MAILTO
+	}
+	
+	final private URI baseURI;
+	final private String userName, password;
+	final boolean authPreemptive;
+	
+	private String errorMessage;
+	
+	private boolean calDAV = false, cardDAV = false;
+	private List<ResourceInfo>
+		addressBooks = new LinkedList<ResourceInfo>(),
+		calendars  = new LinkedList<ResourceInfo>();
+	
+	
+	public boolean hasEnabledCalendars() {
+		for (ResourceInfo calendar : calendars)
+			if (calendar.enabled)
+				return true;
+		return false;
+	}
+	
+	
+	@RequiredArgsConstructor(suppressConstructorProperties=true)
+	@Data
+	public static class ResourceInfo implements Serializable {
+		private static final long serialVersionUID = -5516934508229552112L;
+		
+		public enum Type {
+			ADDRESS_BOOK,
+			CALENDAR
+		}
+		
+		boolean enabled = false;
+		
+		final Type type;
+		final boolean readOnly;
+		final String URL, title, description, color;
+
+		VCardVersion vCardVersion;
+
+		String timezone;
+	}
+}

app/src/main/java/at/bitfire/davdroid/syncadapter/AccountAuthenticatorService.java

@@ -0,0 +1,86 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.syncadapter;
+
+import android.accounts.AbstractAccountAuthenticator;
+import android.accounts.Account;
+import android.accounts.AccountAuthenticatorResponse;
+import android.accounts.AccountManager;
+import android.accounts.NetworkErrorException;
+import android.app.Service;
+import android.content.Context;
+import android.content.Intent;
+import android.os.Bundle;
+import android.os.IBinder;
+
+public class AccountAuthenticatorService extends Service {
+	private static AccountAuthenticator accountAuthenticator;
+
+	private AccountAuthenticator getAuthenticator() {
+		if (accountAuthenticator != null)
+			return accountAuthenticator;
+		return accountAuthenticator = new AccountAuthenticator(this);
+	}
+	
+	@Override
+	public IBinder onBind(Intent intent) {
+		if (intent.getAction().equals(android.accounts.AccountManager.ACTION_AUTHENTICATOR_INTENT))
+			return getAuthenticator().getIBinder(); 
+		return null;
+	}
+	
+	
+	private static class AccountAuthenticator extends AbstractAccountAuthenticator {
+		Context context;
+		
+		public AccountAuthenticator(Context context) {
+			super(context);
+			this.context = context;
+		}
+
+		@Override
+		public Bundle addAccount(AccountAuthenticatorResponse response, String accountType, String authTokenType,
+				String[] requiredFeatures, Bundle options) throws NetworkErrorException {
+			Intent intent = new Intent(context, AddAccountActivity.class);
+			intent.putExtra(AccountManager.KEY_ACCOUNT_AUTHENTICATOR_RESPONSE, response);
+			Bundle bundle = new Bundle();
+			bundle.putParcelable(AccountManager.KEY_INTENT, intent);
+			return bundle;
+		}
+
+		@Override
+		public Bundle confirmCredentials(AccountAuthenticatorResponse response, Account account, Bundle options) throws NetworkErrorException {
+			return null;
+		}
+
+		@Override
+		public Bundle editProperties(AccountAuthenticatorResponse response, String accountType) {
+			return null;
+		}
+
+		@Override
+		public Bundle getAuthToken(AccountAuthenticatorResponse response, Account account, String authTokenType, Bundle options) throws NetworkErrorException {
+			return null;
+		}
+
+		@Override
+		public String getAuthTokenLabel(String authTokenType) {
+			return null;
+		}
+
+		@Override
+		public Bundle hasFeatures(AccountAuthenticatorResponse response, Account account, String[] features) throws NetworkErrorException {
+			return null;
+		}
+
+		@Override
+		public Bundle updateCredentials(AccountAuthenticatorResponse response, Account account, String authTokenType, Bundle options) throws NetworkErrorException {
+			return null;
+		}
+	}
+}

app/src/main/java/at/bitfire/davdroid/syncadapter/AccountDetailsFragment.java

@@ -0,0 +1,147 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.syncadapter;
+
+import android.accounts.Account;
+import android.accounts.AccountManager;
+import android.app.Fragment;
+import android.content.ContentResolver;
+import android.os.Bundle;
+import android.provider.CalendarContract;
+import android.provider.ContactsContract;
+import android.text.Editable;
+import android.text.TextWatcher;
+import android.view.LayoutInflater;
+import android.view.Menu;
+import android.view.MenuInflater;
+import android.view.MenuItem;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.EditText;
+import android.widget.TextView;
+import android.widget.Toast;
+import at.bitfire.davdroid.Constants;
+import at.bitfire.davdroid.R;
+import at.bitfire.davdroid.resource.LocalCalendar;
+import at.bitfire.davdroid.resource.LocalStorageException;
+import at.bitfire.davdroid.resource.ServerInfo;
+
+public class AccountDetailsFragment extends Fragment implements TextWatcher {
+	public static final String KEY_SERVER_INFO = "server_info";
+	
+	ServerInfo serverInfo;
+	
+	EditText editAccountName;
+	
+	
+	@Override
+	public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
+		View v = inflater.inflate(R.layout.account_details, container, false);
+		
+		serverInfo = (ServerInfo)getArguments().getSerializable(KEY_SERVER_INFO);
+		
+		editAccountName = (EditText)v.findViewById(R.id.account_name);
+		editAccountName.addTextChangedListener(this);
+		editAccountName.setText(serverInfo.getUserName());
+		
+		TextView textAccountNameInfo = (TextView)v.findViewById(R.id.account_name_info);
+		if (!serverInfo.hasEnabledCalendars())
+			textAccountNameInfo.setVisibility(View.GONE);
+	
+		setHasOptionsMenu(true);
+		return v;
+	}
+	
+	
+	@Override
+	public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
+	    inflater.inflate(R.menu.account_details, menu);
+	}
+	
+	@Override
+	public boolean onOptionsItemSelected(MenuItem item) {
+		switch (item.getItemId()) {
+		case R.id.add_account:
+			addAccount();
+			break;
+		default:
+			return false;
+		}
+		return true;
+	}
+
+
+	// actions
+	
+	void addAccount() {
+		ServerInfo serverInfo = (ServerInfo)getArguments().getSerializable(KEY_SERVER_INFO);
+		String accountName = editAccountName.getText().toString();
+		
+		AccountManager accountManager = AccountManager.get(getActivity());
+		Account account = new Account(accountName, Constants.ACCOUNT_TYPE);
+		Bundle userData = AccountSettings.createBundle(serverInfo);
+		
+		boolean syncContacts = false;
+		for (ServerInfo.ResourceInfo addressBook : serverInfo.getAddressBooks())
+			if (addressBook.isEnabled()) {
+				ContentResolver.setIsSyncable(account, ContactsContract.AUTHORITY, 1);
+				syncContacts = true;
+				continue;
+			}
+		if (syncContacts) {
+			ContentResolver.setIsSyncable(account, ContactsContract.AUTHORITY, 1);
+			ContentResolver.setSyncAutomatically(account, ContactsContract.AUTHORITY, true);
+		} else
+			ContentResolver.setIsSyncable(account, ContactsContract.AUTHORITY, 0);
+		
+		if (accountManager.addAccountExplicitly(account, serverInfo.getPassword(), userData)) {
+			// account created, now create calendars
+			boolean syncCalendars = false;
+			for (ServerInfo.ResourceInfo calendar : serverInfo.getCalendars())
+				if (calendar.isEnabled())
+					try {
+						LocalCalendar.create(account, getActivity().getContentResolver(), calendar);
+						syncCalendars = true;
+					} catch (LocalStorageException e) {
+						Toast.makeText(getActivity(), "Couldn't create calendar(s): " + e.getMessage(), Toast.LENGTH_LONG).show();
+					}
+			if (syncCalendars) {
+				ContentResolver.setIsSyncable(account, CalendarContract.AUTHORITY, 1);
+				ContentResolver.setSyncAutomatically(account, CalendarContract.AUTHORITY, true);
+			} else
+				ContentResolver.setIsSyncable(account, CalendarContract.AUTHORITY, 0);
+			
+			getActivity().finish();				
+		} else
+			Toast.makeText(getActivity(), "Couldn't create account (account with this name already existing?)", Toast.LENGTH_LONG).show();
+	}
+
+	
+	// input validation
+	
+	@Override
+	public void onPrepareOptionsMenu(Menu menu) {
+		boolean ok = false;
+		ok = editAccountName.getText().length() > 0;
+		MenuItem item = menu.findItem(R.id.add_account);
+		item.setEnabled(ok);
+	}
+
+	@Override
+	public void beforeTextChanged(CharSequence s, int start, int count, int after) {
+	}
+
+	@Override
+	public void onTextChanged(CharSequence s, int start, int before, int count) {
+		getActivity().invalidateOptionsMenu();
+	}
+
+	@Override
+	public void afterTextChanged(Editable s) {
+	}
+}

app/src/main/java/at/bitfire/davdroid/syncadapter/AccountSettings.java

@@ -0,0 +1,183 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.syncadapter;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+
+import lombok.Cleanup;
+import android.accounts.Account;
+import android.accounts.AccountManager;
+import android.content.ContentResolver;
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.net.Uri;
+import android.os.Bundle;
+import android.provider.CalendarContract;
+import android.provider.CalendarContract.Calendars;
+import android.util.Log;
+import at.bitfire.davdroid.resource.ServerInfo;
+import ezvcard.VCardVersion;
+
+public class AccountSettings {
+	private final static String TAG = "davdroid.AccountSettings";
+	
+	private final static int CURRENT_VERSION = 1;
+	private final static String
+		KEY_SETTINGS_VERSION = "version",
+		
+		KEY_USERNAME = "user_name",
+		KEY_AUTH_PREEMPTIVE = "auth_preemptive",
+		
+		KEY_ADDRESSBOOK_URL = "addressbook_url",
+		KEY_ADDRESSBOOK_CTAG = "addressbook_ctag",
+		KEY_ADDRESSBOOK_VCARD_VERSION = "addressbook_vcard_version";
+	
+	Context context;
+	AccountManager accountManager;
+	Account account;
+	
+	
+	public AccountSettings(Context context, Account account) {
+		this.context = context;
+		this.account = account;
+		
+		accountManager = AccountManager.get(context);
+		
+		synchronized(AccountSettings.class) {
+			int version = 0;
+			try {
+				version = Integer.parseInt(accountManager.getUserData(account, KEY_SETTINGS_VERSION));
+			} catch(NumberFormatException e) {
+			}
+			if (version < CURRENT_VERSION)
+				update(version);
+		}
+	}
+	
+	
+	public static Bundle createBundle(ServerInfo serverInfo) {
+		Bundle bundle = new Bundle();
+		bundle.putString(KEY_SETTINGS_VERSION, String.valueOf(CURRENT_VERSION));
+		bundle.putString(KEY_USERNAME, serverInfo.getUserName());
+		bundle.putString(KEY_AUTH_PREEMPTIVE, Boolean.toString(serverInfo.isAuthPreemptive()));
+		for (ServerInfo.ResourceInfo addressBook : serverInfo.getAddressBooks())
+			if (addressBook.isEnabled()) {
+				bundle.putString(KEY_ADDRESSBOOK_URL, addressBook.getURL());
+				bundle.putString(KEY_ADDRESSBOOK_VCARD_VERSION, addressBook.getVCardVersion().getVersion());
+				continue;
+			}
+		return bundle;
+	}
+	
+	
+	// general settings
+	
+	public String getUserName() {
+		return accountManager.getUserData(account, KEY_USERNAME);		
+	}
+	
+	public String getPassword() {
+		return accountManager.getPassword(account);
+	}
+	
+	public boolean getPreemptiveAuth() {
+		return Boolean.parseBoolean(accountManager.getUserData(account, KEY_AUTH_PREEMPTIVE));
+	}
+	
+	
+	// address book (CardDAV) settings
+	
+	public String getAddressBookURL() {
+		return accountManager.getUserData(account, KEY_ADDRESSBOOK_URL);
+	}
+	
+	public String getAddressBookCTag() {
+		return accountManager.getUserData(account, KEY_ADDRESSBOOK_CTAG);
+	}
+	
+	public void setAddressBookCTag(String cTag) {
+		accountManager.setUserData(account, KEY_ADDRESSBOOK_CTAG, cTag);
+	}
+	
+	public VCardVersion getAddressBookVCardVersion() {
+		VCardVersion version = VCardVersion.V3_0;
+		String versionStr = accountManager.getUserData(account, KEY_ADDRESSBOOK_VCARD_VERSION);
+		if (versionStr != null)
+			version = VCardVersion.valueOfByStr(versionStr);
+		return version;
+	}
+	
+	
+	// update from previous account settings
+	
+	private void update(int fromVersion) {
+		Log.i(TAG, "Account settings must be updated from v" + fromVersion + " to v" + CURRENT_VERSION);
+		for (int toVersion = CURRENT_VERSION; toVersion > fromVersion; toVersion--)
+			update(fromVersion, toVersion);
+	}
+	
+	private void update(int fromVersion, int toVersion) {
+		Log.i(TAG, "Updating account settings from v" + fromVersion + " to " + toVersion);
+		try {
+			if (fromVersion == 0 && toVersion == 1)
+				update_0_1();
+			else
+				Log.wtf(TAG, "Don't know how to update settings from v" + fromVersion + " to v" + toVersion);
+		} catch(Exception e) {
+			Log.e(TAG, "Couldn't update account settings (DAVdroid will probably crash)!", e);
+		}
+	}
+	
+	private void update_0_1() throws URISyntaxException {
+		String	v0_principalURL = accountManager.getUserData(account, "principal_url"),
+				v0_addressBookPath = accountManager.getUserData(account, "addressbook_path");
+		Log.d(TAG, "Old principal URL = " + v0_principalURL);
+		Log.d(TAG, "Old address book path = " + v0_addressBookPath);
+		
+		URI principalURI = new URI(v0_principalURL);
+
+		// update address book
+		if (v0_addressBookPath != null) {
+			String addressBookURL = principalURI.resolve(v0_addressBookPath).toASCIIString();
+			Log.d(TAG, "New address book URL = " + addressBookURL);
+			accountManager.setUserData(account, "addressbook_url", addressBookURL);
+		}
+		
+		// update calendars
+		ContentResolver resolver = context.getContentResolver();
+		Uri calendars = Calendars.CONTENT_URI.buildUpon()
+				.appendQueryParameter(Calendars.ACCOUNT_NAME, account.name)
+				.appendQueryParameter(Calendars.ACCOUNT_TYPE, account.type)
+				.appendQueryParameter(CalendarContract.CALLER_IS_SYNCADAPTER, "true").build();
+		@Cleanup Cursor cursor = resolver.query(calendars, new String[] { Calendars._ID, Calendars.NAME }, null, null, null);
+		while (cursor != null && cursor.moveToNext()) {
+			int id = cursor.getInt(0);
+			String	v0_path = cursor.getString(1),
+					v1_url = principalURI.resolve(v0_path).toASCIIString();
+			Log.d(TAG, "Updating calendar #" + id + " name: " + v0_path + " -> " + v1_url);
+			Uri calendar = ContentUris.appendId(Calendars.CONTENT_URI.buildUpon()
+					.appendQueryParameter(Calendars.ACCOUNT_NAME, account.name)
+					.appendQueryParameter(Calendars.ACCOUNT_TYPE, account.type)
+					.appendQueryParameter(CalendarContract.CALLER_IS_SYNCADAPTER, "true"), id).build();
+			ContentValues newValues = new ContentValues(1);
+			newValues.put(Calendars.NAME, v1_url);
+			if (resolver.update(calendar, newValues, null, null) != 1)
+				Log.e(TAG, "Number of modified calendars != 1");
+		}
+		
+		Log.d(TAG, "Cleaning old principal URL and address book path");
+		accountManager.setUserData(account, "principal_url", null);
+		accountManager.setUserData(account, "addressbook_path", null);
+		
+		Log.d(TAG, "Updated settings successfully!");
+		accountManager.setUserData(account, KEY_SETTINGS_VERSION, "1");
+	}
+}

app/src/main/java/at/bitfire/davdroid/syncadapter/AddAccountActivity.java

@@ -0,0 +1,46 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.syncadapter;
+
+import android.app.Activity;
+import android.content.Intent;
+import android.net.Uri;
+import android.os.Bundle;
+import android.view.Menu;
+import android.view.MenuInflater;
+import android.view.MenuItem;
+import at.bitfire.davdroid.Constants;
+import at.bitfire.davdroid.R;
+
+public class AddAccountActivity extends Activity {
+
+	@Override
+	protected void onCreate(Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+		
+		setContentView(R.layout.add_account);
+		
+		if (savedInstanceState == null) {	// first call
+			getFragmentManager().beginTransaction()
+				.add(R.id.fragment_container, new LoginTypeFragment(), "login_type")
+				.commit();
+		}
+	}
+
+	@Override
+	public boolean onCreateOptionsMenu(Menu menu) {
+		MenuInflater inflater = getMenuInflater();
+		inflater.inflate(R.menu.add_account, menu);
+		return true;
+	}
+
+	public void showHelp(MenuItem item) {
+		startActivityForResult(new Intent(Intent.ACTION_VIEW, Uri.parse(Constants.WEB_URL_HELP)), 0);
+	}
+
+}

app/src/main/java/at/bitfire/davdroid/syncadapter/CalendarsSyncAdapterService.java

@@ -0,0 +1,81 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.syncadapter;
+
+import java.net.URISyntaxException;
+import java.util.HashMap;
+import java.util.Map;
+
+import android.accounts.Account;
+import android.app.Service;
+import android.content.ContentProviderClient;
+import android.content.Context;
+import android.content.Intent;
+import android.os.IBinder;
+import android.os.RemoteException;
+import android.util.Log;
+import at.bitfire.davdroid.resource.CalDavCalendar;
+import at.bitfire.davdroid.resource.LocalCalendar;
+import at.bitfire.davdroid.resource.LocalCollection;
+import at.bitfire.davdroid.resource.RemoteCollection;
+
+public class CalendarsSyncAdapterService extends Service {
+	private static SyncAdapter syncAdapter;
+	
+	
+	@Override
+	public void onCreate() {
+		if (syncAdapter == null)
+			syncAdapter = new SyncAdapter(getApplicationContext());
+	}
+
+	@Override
+	public void onDestroy() {
+		syncAdapter.close();
+		syncAdapter = null;
+	}
+
+	@Override
+	public IBinder onBind(Intent intent) {
+		return syncAdapter.getSyncAdapterBinder(); 
+	}
+	
+
+	private static class SyncAdapter extends DavSyncAdapter {
+		private final static String TAG = "davdroid.CalendarsSyncAdapter";
+
+		
+		private SyncAdapter(Context context) {
+			super(context);
+		}
+		
+		@Override
+		protected Map<LocalCollection<?>, RemoteCollection<?>> getSyncPairs(Account account, ContentProviderClient provider) {
+			AccountSettings settings = new AccountSettings(getContext(), account);
+			String	userName = settings.getUserName(),
+					password = settings.getPassword();
+			boolean preemptive = settings.getPreemptiveAuth();
+
+			try {
+				Map<LocalCollection<?>, RemoteCollection<?>> map = new HashMap<LocalCollection<?>, RemoteCollection<?>>();
+				
+				for (LocalCalendar calendar : LocalCalendar.findAll(account, provider)) {
+					RemoteCollection<?> dav = new CalDavCalendar(httpClient, calendar.getUrl(), userName, password, preemptive);
+					map.put(calendar, dav);
+				}
+				return map;
+			} catch (RemoteException ex) {
+				Log.e(TAG, "Couldn't find local calendars", ex);
+			} catch (URISyntaxException ex) {
+				Log.e(TAG, "Couldn't build calendar URI", ex);
+			}
+			
+			return null;
+		}
+	}
+}

app/src/main/java/at/bitfire/davdroid/syncadapter/ContactsSyncAdapterService.java

@@ -0,0 +1,82 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.syncadapter;
+
+import java.net.URISyntaxException;
+import java.util.HashMap;
+import java.util.Map;
+
+import android.accounts.Account;
+import android.app.Service;
+import android.content.ContentProviderClient;
+import android.content.Context;
+import android.content.Intent;
+import android.os.IBinder;
+import android.util.Log;
+import at.bitfire.davdroid.resource.CardDavAddressBook;
+import at.bitfire.davdroid.resource.LocalAddressBook;
+import at.bitfire.davdroid.resource.LocalCollection;
+import at.bitfire.davdroid.resource.RemoteCollection;
+
+public class ContactsSyncAdapterService extends Service {
+	private static ContactsSyncAdapter syncAdapter;
+
+	
+	@Override
+	public void onCreate() {
+		if (syncAdapter == null)
+			syncAdapter = new ContactsSyncAdapter(getApplicationContext());
+	}
+
+	@Override
+	public void onDestroy() {
+		syncAdapter.close();
+		syncAdapter = null;
+	}
+
+	@Override
+	public IBinder onBind(Intent intent) {
+		return syncAdapter.getSyncAdapterBinder();
+	}
+	
+
+	private static class ContactsSyncAdapter extends DavSyncAdapter {
+		private final static String TAG = "davdroid.ContactsSyncAdapter";
+
+		
+		private ContactsSyncAdapter(Context context) {
+			super(context);
+		}
+
+		@Override
+		protected Map<LocalCollection<?>, RemoteCollection<?>> getSyncPairs(Account account, ContentProviderClient provider) {
+			AccountSettings settings = new AccountSettings(getContext(), account);
+			String	userName = settings.getUserName(),
+					password = settings.getPassword();
+			boolean preemptive = settings.getPreemptiveAuth();
+
+			String addressBookURL = settings.getAddressBookURL();
+			if (addressBookURL == null)
+				return null;
+			
+			try {
+				LocalCollection<?> database = new LocalAddressBook(account, provider, settings);
+				RemoteCollection<?> dav = new CardDavAddressBook(httpClient, addressBookURL, userName, password, preemptive);
+				
+				Map<LocalCollection<?>, RemoteCollection<?>> map = new HashMap<LocalCollection<?>, RemoteCollection<?>>();
+				map.put(database, dav);
+				
+				return map;
+			} catch (URISyntaxException ex) {
+				Log.e(TAG, "Couldn't build address book URI", ex);
+			}
+			
+			return null;
+		}
+	}
+}

app/src/main/java/at/bitfire/davdroid/syncadapter/DavSyncAdapter.java

@@ -0,0 +1,166 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.syncadapter;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.util.Map;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+import lombok.Getter;
+
+import org.apache.http.HttpStatus;
+
+import android.accounts.Account;
+import android.accounts.AccountManager;
+import android.content.AbstractThreadedSyncAdapter;
+import android.content.ContentProviderClient;
+import android.content.ContentResolver;
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.content.SyncResult;
+import android.os.AsyncTask;
+import android.os.Bundle;
+import android.preference.PreferenceManager;
+import android.provider.Settings;
+import android.util.Log;
+import at.bitfire.davdroid.Constants;
+import at.bitfire.davdroid.resource.LocalCollection;
+import at.bitfire.davdroid.resource.LocalStorageException;
+import at.bitfire.davdroid.resource.RemoteCollection;
+import at.bitfire.davdroid.webdav.DavException;
+import at.bitfire.davdroid.webdav.DavHttpClient;
+import at.bitfire.davdroid.webdav.HttpException;
+import org.apache.http.impl.client.CloseableHttpClient;
+
+public abstract class DavSyncAdapter extends AbstractThreadedSyncAdapter implements Closeable {
+	private final static String TAG = "davdroid.DavSyncAdapter";
+	
+	@Getter private static String androidID;
+	
+	protected AccountManager accountManager;
+	
+	/* We use one static httpClient for
+	 *   - all sync adapters  (CalendarsSyncAdapter, ContactsSyncAdapter)
+	 *   - and all threads (= accounts) of each sync adapter
+	 * so that HttpClient's threaded pool management can do its best.
+	 */
+	protected static CloseableHttpClient httpClient;
+
+	/* One static read/write lock pair for the static httpClient:
+	 *    Use the READ  lock when httpClient will only be called (to prevent it from being unset while being used).
+	 *    Use the WRITE lock when httpClient will be modified (set/unset). */
+	private final static ReentrantReadWriteLock httpClientLock = new ReentrantReadWriteLock();
+
+	
+	public DavSyncAdapter(Context context) {
+		super(context, true);
+		
+		synchronized(this) {
+			if (androidID == null)
+				androidID = Settings.Secure.getString(context.getContentResolver(), Settings.Secure.ANDROID_ID);
+		}
+		
+		accountManager = AccountManager.get(context);
+	}
+	
+	@Override
+	public void close() {
+		Log.d(TAG, "Closing httpClient");
+		
+		// may be called from a GUI thread, so we need an AsyncTask
+		new AsyncTask<Void, Void, Void>() {
+			@Override
+			protected Void doInBackground(Void... params) {
+				try {
+					httpClientLock.writeLock().lock();
+					if (httpClient != null) {
+						httpClient.close();
+						httpClient = null;
+					}
+					httpClientLock.writeLock().unlock();
+				} catch (IOException e) {
+					Log.w(TAG, "Couldn't close HTTP client", e);
+				}
+				return null;
+			}
+		}.execute();
+	}
+	
+	protected abstract Map<LocalCollection<?>, RemoteCollection<?>> getSyncPairs(Account account, ContentProviderClient provider);
+	
+
+	@Override
+	public void onPerformSync(Account account, Bundle extras, String authority,	ContentProviderClient provider, SyncResult syncResult) {
+		Log.i(TAG, "Performing sync for authority " + authority);
+		
+		// set class loader for iCal4j ResourceLoader
+		Thread.currentThread().setContextClassLoader(getContext().getClassLoader());
+		
+		// create httpClient, if necessary
+		httpClientLock.writeLock().lock();
+		if (httpClient == null) {
+			Log.d(TAG, "Creating new DavHttpClient");
+			SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(getContext());
+			httpClient = DavHttpClient.create(
+				settings.getBoolean(Constants.SETTING_DISABLE_COMPRESSION, false),
+				settings.getBoolean(Constants.SETTING_NETWORK_LOGGING, false)
+			);
+		}
+		
+		// prevent httpClient shutdown until we're ready by holding a read lock
+		// acquiring read lock before releasing write lock will downgrade the write lock to a read lock
+		httpClientLock.readLock().lock();
+		httpClientLock.writeLock().unlock();
+
+		// TODO use VCard 4.0 if possible
+		AccountSettings accountSettings = new AccountSettings(getContext(), account);
+		Log.d(TAG, "Server supports VCard version " + accountSettings.getAddressBookVCardVersion());
+
+		try {
+			// get local <-> remote collection pairs
+			Map<LocalCollection<?>, RemoteCollection<?>> syncCollections = getSyncPairs(account, provider);
+			if (syncCollections == null)
+				Log.i(TAG, "Nothing to synchronize");
+			else
+				try {
+					for (Map.Entry<LocalCollection<?>, RemoteCollection<?>> entry : syncCollections.entrySet())
+						new SyncManager(entry.getKey(), entry.getValue()).synchronize(extras.containsKey(ContentResolver.SYNC_EXTRAS_MANUAL), syncResult);
+				} catch (DavException ex) {
+					syncResult.stats.numParseExceptions++;
+					Log.e(TAG, "Invalid DAV response", ex);
+				} catch (HttpException ex) {
+					if (ex.getCode() == HttpStatus.SC_UNAUTHORIZED) {
+						Log.e(TAG, "HTTP Unauthorized " + ex.getCode(), ex);
+						syncResult.stats.numAuthExceptions++;
+					} else if (ex.isClientError()) {
+						Log.e(TAG, "Hard HTTP error " + ex.getCode(), ex);
+						syncResult.stats.numParseExceptions++;
+					} else {
+						Log.w(TAG, "Soft HTTP error " + ex.getCode() + " (Android will try again later)", ex);
+						syncResult.stats.numIoExceptions++;
+					}
+				} catch (LocalStorageException ex) {
+					syncResult.databaseError = true;
+					Log.e(TAG, "Local storage (content provider) exception", ex);
+				} catch (IOException ex) {
+					syncResult.stats.numIoExceptions++;
+					Log.e(TAG, "I/O error (Android will try again later)", ex);
+				} catch (URISyntaxException ex) {
+					Log.e(TAG, "Invalid URI (file name) syntax", ex);
+				}
+		} finally {
+			// allow httpClient shutdown
+			httpClientLock.readLock().unlock();
+		}
+		
+		Log.i(TAG, "Sync complete for " + authority);
+	}
+
+}

app/src/main/java/at/bitfire/davdroid/syncadapter/GeneralSettingsActivity.java

@@ -0,0 +1,54 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.syncadapter;
+
+import android.app.Activity;
+import android.content.Context;
+import android.content.Intent;
+import android.net.Uri;
+import android.os.Bundle;
+import android.preference.PreferenceFragment;
+import android.view.Menu;
+import android.view.MenuInflater;
+import android.view.MenuItem;
+import at.bitfire.davdroid.R;
+
+public class GeneralSettingsActivity extends Activity {
+	final static String URL_REPORT_ISSUE = "https://github.com/bitfireAT/davdroid/blob/master/CONTRIBUTING.md#reporting-issues"; 
+	
+	@Override
+	public void onCreate(Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+		
+		getFragmentManager().beginTransaction()
+			.replace(android.R.id.content, new GeneralSettingsFragment())
+        	.commit();
+	}
+	
+	public void reportIssue(MenuItem item) {
+		startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse(URL_REPORT_ISSUE)));
+	}
+	
+	
+	public static class GeneralSettingsFragment extends PreferenceFragment {
+	    @Override
+	    public void onCreate(Bundle savedInstanceState) {
+	        super.onCreate(savedInstanceState);
+	        
+			getPreferenceManager().setSharedPreferencesMode(Context.MODE_MULTI_PROCESS);
+	        addPreferencesFromResource(R.xml.general_settings);
+	        
+	        setHasOptionsMenu(true);
+	    }
+		
+		@Override
+		public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
+			inflater.inflate(R.menu.debug_settings, menu);
+		}
+	}
+}

app/src/main/java/at/bitfire/davdroid/syncadapter/LoginEmailFragment.java

@@ -0,0 +1,111 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.syncadapter;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+
+import android.app.DialogFragment;
+import android.app.Fragment;
+import android.app.FragmentTransaction;
+import android.os.Bundle;
+import android.text.Editable;
+import android.text.TextWatcher;
+import android.view.LayoutInflater;
+import android.view.Menu;
+import android.view.MenuInflater;
+import android.view.MenuItem;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.EditText;
+import at.bitfire.davdroid.R;
+
+public class LoginEmailFragment extends Fragment implements TextWatcher {
+	
+	protected EditText editEmail, editPassword; 
+	
+
+	@Override
+	public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
+		View v = inflater.inflate(R.layout.login_email, container, false);
+
+		editEmail = (EditText)v.findViewById(R.id.email_address);
+		editEmail.addTextChangedListener(this);
+		editPassword = (EditText)v.findViewById(R.id.password);
+		editPassword.addTextChangedListener(this);
+		
+		setHasOptionsMenu(true);
+		return v;
+	}
+
+	@Override
+	public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
+	    inflater.inflate(R.menu.only_next, menu);
+	}
+	
+	@Override
+	public boolean onOptionsItemSelected(MenuItem item) {
+		switch (item.getItemId()) {
+		case R.id.next:
+			FragmentTransaction ft = getFragmentManager().beginTransaction();
+			
+			Bundle args = new Bundle();
+			String email = editEmail.getText().toString();
+			args.putString(QueryServerDialogFragment.EXTRA_BASE_URI, "mailto:" + email);
+			args.putString(QueryServerDialogFragment.EXTRA_USER_NAME, email);
+			args.putString(QueryServerDialogFragment.EXTRA_PASSWORD, editPassword.getText().toString());
+			args.putBoolean(QueryServerDialogFragment.EXTRA_AUTH_PREEMPTIVE, true);
+			
+			DialogFragment dialog = new QueryServerDialogFragment();
+			dialog.setArguments(args);
+		    dialog.show(ft, QueryServerDialogFragment.class.getName());
+			break;
+		default:
+			return false;
+		}
+		return true;
+	}
+
+	
+	// input validation
+	
+	@Override
+	public void onPrepareOptionsMenu(Menu menu) {
+		boolean	emailOk = false,
+				passwordOk = editPassword.getText().length() > 0;
+
+		String email = editEmail.getText().toString();
+		try {
+			URI uri = new URI("mailto:" + email);
+			if (uri.isOpaque()) {
+				int pos = email.lastIndexOf("@");
+				if (pos != -1)
+					emailOk = !email.substring(pos+1).isEmpty();
+			}
+		} catch (URISyntaxException e) {
+			// invalid mailto: URI
+		}
+		
+		MenuItem item = menu.findItem(R.id.next);
+		item.setEnabled(emailOk && passwordOk);
+	}
+	
+	@Override
+	public void beforeTextChanged(CharSequence s, int start, int count, int after) {
+	}
+
+	@Override
+	public void onTextChanged(CharSequence s, int start, int before, int count) {
+		getActivity().invalidateOptionsMenu();
+	}
+
+	@Override
+	public void afterTextChanged(Editable s) {
+	}
+
+}

app/src/main/java/at/bitfire/davdroid/syncadapter/LoginTypeFragment.java

@@ -0,0 +1,57 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.syncadapter;
+
+import android.app.Fragment;
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.Menu;
+import android.view.MenuInflater;
+import android.view.MenuItem;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.RadioButton;
+import at.bitfire.davdroid.R;
+
+public class LoginTypeFragment extends Fragment {
+	
+	protected RadioButton btnTypeEmail, btnTypeURL;
+	
+
+	@Override
+	public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
+		View v = inflater.inflate(R.layout.login_type, container, false);
+		
+		btnTypeEmail = (RadioButton)v.findViewById(R.id.login_type_email);
+		btnTypeURL = (RadioButton)v.findViewById(R.id.login_type_url);
+		
+		setHasOptionsMenu(true);
+		
+		return v;
+	}
+	
+	@Override
+	public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
+	    inflater.inflate(R.menu.only_next, menu);
+	}
+	
+	@Override
+	public boolean onOptionsItemSelected(MenuItem item) {
+		switch (item.getItemId()) {
+		case R.id.next:
+			Fragment loginFragment = btnTypeEmail.isChecked() ? new LoginEmailFragment() : new LoginURLFragment();
+			getFragmentManager().beginTransaction()
+				.replace(R.id.fragment_container, loginFragment)
+				.addToBackStack(null)
+				.commitAllowingStateLoss();
+			return true;
+		default:
+			return false;
+		}
+	}
+}

app/src/main/java/at/bitfire/davdroid/syncadapter/LoginURLFragment.java

@@ -0,0 +1,153 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.syncadapter;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+
+import org.apache.commons.lang.StringUtils;
+
+import android.app.DialogFragment;
+import android.app.Fragment;
+import android.app.FragmentTransaction;
+import android.os.Bundle;
+import android.text.Editable;
+import android.text.TextWatcher;
+import android.view.LayoutInflater;
+import android.view.Menu;
+import android.view.MenuInflater;
+import android.view.MenuItem;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.AdapterView;
+import android.widget.AdapterView.OnItemSelectedListener;
+import android.widget.Button;
+import android.widget.CheckBox;
+import android.widget.EditText;
+import android.widget.Spinner;
+import android.widget.TextView;
+import at.bitfire.davdroid.R;
+
+public class LoginURLFragment extends Fragment implements TextWatcher {
+	
+	protected Spinner spnrScheme;
+	protected TextView textHttpWarning;
+	protected EditText editBaseURI, editUserName, editPassword;
+	protected CheckBox checkboxPreemptive;
+	protected Button btnNext;
+	
+
+	@Override
+	public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
+		View v = inflater.inflate(R.layout.login_url, container, false);
+		
+		// protocol selection spinner
+		textHttpWarning = (TextView)v.findViewById(R.id.http_warning);
+		
+		spnrScheme = (Spinner)v.findViewById(R.id.login_scheme);
+		spnrScheme.setOnItemSelectedListener(new OnItemSelectedListener() {
+			@Override
+			public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
+				String scheme = parent.getAdapter().getItem(position).toString();
+				textHttpWarning.setVisibility(scheme.equals("https://") ? View.GONE : View.VISIBLE);
+			}
+
+			@Override
+			public void onNothingSelected(AdapterView<?> parent) {
+			}
+		});
+		spnrScheme.setSelection(1);	// HTTPS
+
+		// other input fields
+		editBaseURI = (EditText)v.findViewById(R.id.login_host_path);
+		editBaseURI.addTextChangedListener(this);
+		
+		editUserName = (EditText)v.findViewById(R.id.userName);
+		editUserName.addTextChangedListener(this);
+		
+		editPassword = (EditText)v.findViewById(R.id.password);
+		editPassword.addTextChangedListener(this);
+		
+		checkboxPreemptive = (CheckBox) v.findViewById(R.id.auth_preemptive);
+		
+		// hook into action bar
+		setHasOptionsMenu(true);
+
+		return v;
+	}
+
+	@Override
+	public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
+	    inflater.inflate(R.menu.only_next, menu);
+	}
+	
+	@Override
+	public boolean onOptionsItemSelected(MenuItem item) {
+		switch (item.getItemId()) {
+		case R.id.next:
+			FragmentTransaction ft = getFragmentManager().beginTransaction();
+			
+			Bundle args = new Bundle();
+			try {
+				args.putString(QueryServerDialogFragment.EXTRA_BASE_URI, getBaseURI().toString());
+			} catch (URISyntaxException e) {
+			}
+			args.putString(QueryServerDialogFragment.EXTRA_USER_NAME, editUserName.getText().toString());
+			args.putString(QueryServerDialogFragment.EXTRA_PASSWORD, editPassword.getText().toString());
+			args.putBoolean(QueryServerDialogFragment.EXTRA_AUTH_PREEMPTIVE, checkboxPreemptive.isChecked());
+			
+			DialogFragment dialog = new QueryServerDialogFragment();
+			dialog.setArguments(args);
+		    dialog.show(ft, QueryServerDialogFragment.class.getName());
+			break;
+		default:
+			return false;
+		}
+		return true;
+	}
+	
+	
+	private URI getBaseURI() throws URISyntaxException {
+		String	scheme = spnrScheme.getSelectedItem().toString(),
+				host_path = editBaseURI.getText().toString();
+		return new URI(scheme + host_path);
+	}
+
+	
+	// input validation
+	
+	@Override
+	public void onPrepareOptionsMenu(Menu menu) {
+		boolean usernameOk = editUserName.getText().length() > 0,
+				passwordOk = editPassword.getText().length() > 0,
+				urlOk = false;
+				
+		// check host name
+		try {
+			if (!StringUtils.isBlank(getBaseURI().getHost()))
+				urlOk = true;
+		} catch (Exception e) {
+		}
+			
+		MenuItem item = menu.findItem(R.id.next);
+		item.setEnabled(usernameOk && passwordOk && urlOk);
+	}
+
+	@Override
+	public void beforeTextChanged(CharSequence s, int start, int count, int after) {
+	}
+
+	@Override
+	public void onTextChanged(CharSequence s, int start, int before, int count) {
+		getActivity().invalidateOptionsMenu();
+	}
+
+	@Override
+	public void afterTextChanged(Editable s) {
+	}
+}

app/src/main/java/at/bitfire/davdroid/syncadapter/QueryServerDialogFragment.java

@@ -0,0 +1,129 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.syncadapter;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+
+import lombok.Cleanup;
+import android.app.DialogFragment;
+import android.app.LoaderManager.LoaderCallbacks;
+import android.content.AsyncTaskLoader;
+import android.content.Context;
+import android.content.Loader;
+import android.os.Bundle;
+import android.util.Log;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.ProgressBar;
+import android.widget.Toast;
+import at.bitfire.davdroid.R;
+import at.bitfire.davdroid.resource.DavResourceFinder;
+import at.bitfire.davdroid.resource.ServerInfo;
+import at.bitfire.davdroid.webdav.DavException;
+import org.apache.http.HttpException;
+
+public class QueryServerDialogFragment extends DialogFragment implements LoaderCallbacks<ServerInfo> {
+	private static final String TAG = "davdroid.QueryServerDialogFragment";
+	public static final String
+		EXTRA_BASE_URI = "base_uri",
+		EXTRA_USER_NAME = "user_name",
+		EXTRA_PASSWORD = "password",
+		EXTRA_AUTH_PREEMPTIVE = "auth_preemptive";
+	
+	ProgressBar progressBar;
+	
+	@Override
+	public void onCreate(Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+		setStyle(DialogFragment.STYLE_NO_TITLE, android.R.style.Theme_Holo_Light_Dialog);
+		setCancelable(false);
+
+		Loader<ServerInfo> loader = getLoaderManager().initLoader(0, getArguments(), this);
+		if (savedInstanceState == null)		// http://code.google.com/p/android/issues/detail?id=14944
+			loader.forceLoad();
+	}
+
+	@Override
+	public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
+		View v = inflater.inflate(R.layout.query_server, container, false);
+		return v;
+	}
+
+	@Override
+	public Loader<ServerInfo> onCreateLoader(int id, Bundle args) {
+		Log.i(TAG, "onCreateLoader");
+		return new ServerInfoLoader(getActivity(), args);
+	}
+
+	@Override
+	public void onLoadFinished(Loader<ServerInfo> loader, ServerInfo serverInfo) {
+		if (serverInfo.getErrorMessage() != null)
+			Toast.makeText(getActivity(), serverInfo.getErrorMessage(), Toast.LENGTH_LONG).show();
+		else {
+			SelectCollectionsFragment selectCollections = new SelectCollectionsFragment();
+			Bundle arguments = new Bundle();
+			arguments.putSerializable(SelectCollectionsFragment.KEY_SERVER_INFO, serverInfo);
+			selectCollections.setArguments(arguments);
+			
+			getFragmentManager().beginTransaction()
+				.replace(R.id.fragment_container, selectCollections)
+				.addToBackStack(null)
+				.commitAllowingStateLoss();
+		}
+		
+		getDialog().dismiss();
+	}
+
+	@Override
+	public void onLoaderReset(Loader<ServerInfo> arg0) {
+	}
+	
+	
+	static class ServerInfoLoader extends AsyncTaskLoader<ServerInfo> {
+		private static final String TAG = "davdroid.ServerInfoLoader";
+		final Bundle args;
+		final Context context;
+		
+		public ServerInfoLoader(Context context, Bundle args) {
+			super(context);
+			this.context = context;
+			this.args = args;
+		}
+
+		@Override
+		public ServerInfo loadInBackground() {
+			ServerInfo serverInfo = new ServerInfo(
+				URI.create(args.getString(EXTRA_BASE_URI)),
+				args.getString(EXTRA_USER_NAME),
+				args.getString(EXTRA_PASSWORD),
+				args.getBoolean(EXTRA_AUTH_PREEMPTIVE)
+			);
+			
+			try {
+				@Cleanup DavResourceFinder finder = new DavResourceFinder(context);
+				finder.findResources(serverInfo);
+			} catch (URISyntaxException e) {
+				serverInfo.setErrorMessage(getContext().getString(R.string.exception_uri_syntax, e.getMessage()));
+			}  catch (IOException e) {
+				serverInfo.setErrorMessage(getContext().getString(R.string.exception_io, e.getLocalizedMessage()));
+			} catch (HttpException e) {
+				Log.e(TAG, "HTTP error while querying server info", e);
+				serverInfo.setErrorMessage(getContext().getString(R.string.exception_http, e.getLocalizedMessage()));
+			} catch (DavException e) {
+				Log.e(TAG, "DAV error while querying server info", e);
+				serverInfo.setErrorMessage(getContext().getString(R.string.exception_incapable_resource, e.getLocalizedMessage()));
+			}
+			
+			return serverInfo;
+		}
+		
+	}
+}

app/src/main/java/at/bitfire/davdroid/syncadapter/SelectCollectionsAdapter.java

@@ -0,0 +1,161 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.syncadapter;
+
+import lombok.Getter;
+import android.annotation.SuppressLint;
+import android.content.Context;
+import android.text.Html;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.BaseAdapter;
+import android.widget.CheckedTextView;
+import android.widget.ListAdapter;
+import at.bitfire.davdroid.R;
+import at.bitfire.davdroid.resource.ServerInfo;
+import at.bitfire.davdroid.resource.ServerInfo.ResourceInfo.Type;
+
+public class SelectCollectionsAdapter extends BaseAdapter implements ListAdapter {
+	final static int TYPE_ADDRESS_BOOKS_HEADING = 0,
+		TYPE_ADDRESS_BOOKS_ROW = 1,
+		TYPE_CALENDARS_HEADING = 2,
+		TYPE_CALENDARS_ROW = 3;
+	
+	protected Context context;
+	protected ServerInfo serverInfo;
+	@Getter protected int nAddressBooks, nCalendars;
+	
+	
+	public SelectCollectionsAdapter(Context context, ServerInfo serverInfo) {
+		this.context = context;
+		
+		this.serverInfo = serverInfo;
+		nAddressBooks = (serverInfo.getAddressBooks() == null) ? 0 : serverInfo.getAddressBooks().size();
+		nCalendars = (serverInfo.getCalendars() == null) ? 0 : serverInfo.getCalendars().size();
+	}
+	
+	
+	// item data
+	
+	@Override
+	public int getCount() {
+		return nAddressBooks + nCalendars + 2;
+	}
+
+	@Override
+	public Object getItem(int position) {
+		if (position > 0 && position <= nAddressBooks)
+			return serverInfo.getAddressBooks().get(position - 1);
+		else if (position > nAddressBooks + 1)
+			return serverInfo.getCalendars().get(position - nAddressBooks - 2);
+		return null;
+	}
+	
+	@Override
+	public boolean hasStableIds() {
+		return true;
+	}
+
+	@Override
+	public long getItemId(int position) {
+		return position;
+	}
+	
+	
+	// item views
+
+	@Override
+	public int getViewTypeCount() {
+		return 4;
+	}
+
+	@Override
+	public int getItemViewType(int position) {
+		if (position == 0)
+			return TYPE_ADDRESS_BOOKS_HEADING;
+		else if (position <= nAddressBooks)
+			return TYPE_ADDRESS_BOOKS_ROW;
+		else if (position == nAddressBooks + 1)
+			return TYPE_CALENDARS_HEADING;
+		else if (position <= nAddressBooks + nCalendars + 1)
+			return TYPE_CALENDARS_ROW;
+		else
+			return IGNORE_ITEM_VIEW_TYPE;
+	}
+
+	@Override
+	@SuppressLint("InflateParams")
+	public View getView(int position, View convertView, ViewGroup parent) {
+		View v = convertView;
+		
+		// step 1: get view (either by creating or recycling)
+		if (v == null) {
+			LayoutInflater inflater = LayoutInflater.from(parent.getContext());
+			switch (getItemViewType(position)) {
+			case TYPE_ADDRESS_BOOKS_HEADING:
+				v = inflater.inflate(R.layout.address_books_heading, parent, false);
+				break;
+			case TYPE_ADDRESS_BOOKS_ROW:
+				v = inflater.inflate(android.R.layout.simple_list_item_single_choice, null);
+				v.setPadding(0, 8, 0, 8);
+				break;
+			case TYPE_CALENDARS_HEADING:
+				v = inflater.inflate(R.layout.calendars_heading, parent, false);
+				break;
+			case TYPE_CALENDARS_ROW:
+				v = inflater.inflate(android.R.layout.simple_list_item_multiple_choice, null);
+				v.setPadding(0, 8, 0, 8);
+			}
+		}
+		
+		// step 2: fill view with content
+		switch (getItemViewType(position)) {
+		case TYPE_ADDRESS_BOOKS_ROW:
+			setContent((CheckedTextView)v, R.drawable.addressbook, (ServerInfo.ResourceInfo)getItem(position));
+			break;
+		case TYPE_CALENDARS_ROW:
+			setContent((CheckedTextView)v, R.drawable.calendar, (ServerInfo.ResourceInfo)getItem(position));
+		}
+		
+		return v;
+	}
+	
+	protected void setContent(CheckedTextView view, int collectionIcon, ServerInfo.ResourceInfo info) {
+		// set layout and icons
+		view.setCompoundDrawablesWithIntrinsicBounds(collectionIcon, 0, info.isReadOnly() ? R.drawable.ic_read_only : 0, 0);
+		view.setCompoundDrawablePadding(10);
+		
+		// set text		
+		String title = info.getTitle();
+		if (title == null)		// unnamed collection
+			title = context.getString((info.getType() == Type.ADDRESS_BOOK) ?
+					R.string.setup_address_book : R.string.setup_calendar);
+		title = "<b>" + title + "</b>";
+		if (info.isReadOnly())
+			title = title + " (" + context.getString(R.string.setup_read_only) + ")";
+		
+		String description = info.getDescription();
+		if (description == null)
+			description = info.getURL();
+		
+		// FIXME escape HTML
+		view.setText(Html.fromHtml(title + "<br/>" + description));
+	}
+
+	@Override
+	public boolean areAllItemsEnabled() {
+		return false;
+	}
+
+	@Override
+	public boolean isEnabled(int position) {
+		int type = getItemViewType(position);
+		return (type == TYPE_ADDRESS_BOOKS_ROW || type == TYPE_CALENDARS_ROW);
+	}
+}

app/src/main/java/at/bitfire/davdroid/syncadapter/SelectCollectionsFragment.java

@@ -0,0 +1,127 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.syncadapter;
+
+import android.app.ListFragment;
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.Menu;
+import android.view.MenuInflater;
+import android.view.MenuItem;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.AdapterView;
+import android.widget.AdapterView.OnItemClickListener;
+import android.widget.ListAdapter;
+import android.widget.ListView;
+import at.bitfire.davdroid.R;
+import at.bitfire.davdroid.resource.ServerInfo;
+
+public class SelectCollectionsFragment extends ListFragment {
+	public static final String KEY_SERVER_INFO = "server_info";
+	
+	
+	@Override
+	public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
+		View v = super.onCreateView(inflater, container, savedInstanceState);
+		setHasOptionsMenu(true);
+		return v;
+	}
+
+	@Override
+	public void onDestroyView() {
+		super.onDestroyView();
+		setListAdapter(null);
+	}
+
+	@Override
+	public void onViewCreated(View view, Bundle savedInstanceState) {
+		super.onViewCreated(view, savedInstanceState);
+		
+		final ListView listView = getListView();
+		listView.setPadding(20, 30, 20, 30);
+		
+		View header = getActivity().getLayoutInflater().inflate(R.layout.select_collections_header, getListView(), false);
+		listView.addHeaderView(header, getListView(), false);
+		
+		final ServerInfo serverInfo = (ServerInfo)getArguments().getSerializable(KEY_SERVER_INFO);
+		final SelectCollectionsAdapter adapter = new SelectCollectionsAdapter(view.getContext(), serverInfo);
+		setListAdapter(adapter);
+		
+		listView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
+		listView.setOnItemClickListener(new OnItemClickListener() {
+			@Override
+			public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
+				int itemPosition = position - 1;	// one list header view at pos. 0
+				if (adapter.getItemViewType(itemPosition) == SelectCollectionsAdapter.TYPE_ADDRESS_BOOKS_ROW) {
+					// unselect all other address books
+					for (int pos = 1; pos <= adapter.getNAddressBooks(); pos++)
+						if (pos != itemPosition)
+							listView.setItemChecked(pos + 1, false);
+				}
+				
+				getActivity().invalidateOptionsMenu();
+			}
+		});
+	}
+	
+	@Override
+	public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
+	    inflater.inflate(R.menu.only_next, menu);
+	}
+	
+	@Override
+	public boolean onOptionsItemSelected(MenuItem item) {
+		switch (item.getItemId()) {
+		case R.id.next:
+			ServerInfo serverInfo = (ServerInfo)getArguments().getSerializable(KEY_SERVER_INFO);
+			
+			// synchronize only selected collections
+			for (ServerInfo.ResourceInfo addressBook : serverInfo.getAddressBooks())
+				addressBook.setEnabled(false);
+			for (ServerInfo.ResourceInfo calendar : serverInfo.getCalendars())
+				calendar.setEnabled(false);
+			
+			ListAdapter adapter = getListView().getAdapter();
+			for (long id : getListView().getCheckedItemIds()) {
+				int position = (int)id + 1;		// +1 because header view is inserted at pos. 0 
+				ServerInfo.ResourceInfo info = (ServerInfo.ResourceInfo)adapter.getItem(position);
+				info.setEnabled(true);
+			}
+			
+			// pass to "account details" fragment
+			AccountDetailsFragment accountDetails = new AccountDetailsFragment();
+			Bundle arguments = new Bundle();
+			arguments.putSerializable(SelectCollectionsFragment.KEY_SERVER_INFO, serverInfo);
+			accountDetails.setArguments(arguments);
+			
+			getFragmentManager().beginTransaction()
+				.replace(R.id.fragment_container, accountDetails)
+				.addToBackStack(null)
+				.commitAllowingStateLoss();
+			break;
+		default:
+			return false;
+		}
+		return true;
+	}
+	
+	
+	// input validation
+	
+	@Override
+	public void onPrepareOptionsMenu(Menu menu) {
+		boolean ok = false;
+		try {
+			ok = getListView().getCheckedItemCount() > 0;
+		} catch(IllegalStateException e) {
+		}
+		MenuItem item = menu.findItem(R.id.next);
+		item.setEnabled(ok);
+	}
+}

app/src/main/java/at/bitfire/davdroid/syncadapter/SyncManager.java

@@ -0,0 +1,214 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.syncadapter;
+
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.util.HashSet;
+import java.util.Set;
+
+import net.fortuna.ical4j.model.ValidationException;
+import android.content.SyncResult;
+import android.util.Log;
+import at.bitfire.davdroid.ArrayUtils;
+import at.bitfire.davdroid.resource.LocalCollection;
+import at.bitfire.davdroid.resource.LocalStorageException;
+import at.bitfire.davdroid.resource.RecordNotFoundException;
+import at.bitfire.davdroid.resource.RemoteCollection;
+import at.bitfire.davdroid.resource.Resource;
+import at.bitfire.davdroid.webdav.DavException;
+import at.bitfire.davdroid.webdav.HttpException;
+import at.bitfire.davdroid.webdav.NotFoundException;
+import at.bitfire.davdroid.webdav.PreconditionFailedException;
+
+public class SyncManager {
+	private static final String TAG = "davdroid.SyncManager";
+	
+	private static final int MAX_MULTIGET_RESOURCES = 35;
+	
+	protected LocalCollection<? extends Resource> local;
+	protected RemoteCollection<? extends Resource> remote;
+	
+	
+	public SyncManager(LocalCollection<? extends Resource> local, RemoteCollection<? extends Resource> remote) {
+		this.local = local;
+		this.remote = remote;
+	}
+
+	
+	public void synchronize(boolean manualSync, SyncResult syncResult) throws URISyntaxException, LocalStorageException, IOException, HttpException, DavException {
+		// PHASE 1: push local changes to server
+		int	deletedRemotely = pushDeleted(),
+			addedRemotely = pushNew(),
+			updatedRemotely = pushDirty();
+		
+		syncResult.stats.numEntries = deletedRemotely + addedRemotely + updatedRemotely;
+		
+		// PHASE 2A: check if there's a reason to do a sync with remote (= forced sync or remote CTag changed)
+		boolean fetchCollection = syncResult.stats.numEntries > 0;
+		if (manualSync) {
+			Log.i(TAG, "Synchronization forced");
+			fetchCollection = true;
+		}
+		if (!fetchCollection) {
+			String	currentCTag = remote.getCTag(),
+					lastCTag = local.getCTag();
+			Log.d(TAG, "Last local CTag = " + lastCTag + "; current remote CTag = " + currentCTag);
+			if (currentCTag == null || !currentCTag.equals(lastCTag))
+				fetchCollection = true;
+		}
+		
+		if (!fetchCollection) {
+			Log.i(TAG, "No local changes and CTags match, no need to sync");
+			return;
+		}
+		
+		// PHASE 2B: detect details of remote changes
+		Log.i(TAG, "Fetching remote resource list");
+		Set<Resource>	remotelyAdded = new HashSet<Resource>(),
+						remotelyUpdated = new HashSet<Resource>();
+		
+		Resource[] remoteResources = remote.getMemberETags();
+		for (Resource remoteResource : remoteResources) {
+			try {
+				Resource localResource = local.findByRemoteName(remoteResource.getName(), false);
+				if (localResource.getETag() == null || !localResource.getETag().equals(remoteResource.getETag()))
+					remotelyUpdated.add(remoteResource);
+			} catch(RecordNotFoundException e) {
+				remotelyAdded.add(remoteResource);
+			}
+		}
+
+		// PHASE 3: pull remote changes from server
+		syncResult.stats.numInserts = pullNew(remotelyAdded.toArray(new Resource[0]));
+		syncResult.stats.numUpdates = pullChanged(remotelyUpdated.toArray(new Resource[0]));
+		syncResult.stats.numEntries += syncResult.stats.numInserts + syncResult.stats.numUpdates;
+		
+		Log.i(TAG, "Removing non-dirty resources that are not present remotely anymore");
+		local.deleteAllExceptRemoteNames(remoteResources);
+		local.commit();
+
+		// update collection CTag
+		Log.i(TAG, "Sync complete, fetching new CTag");
+		local.setCTag(remote.getCTag());
+	}
+	
+	
+	private int pushDeleted() throws URISyntaxException, LocalStorageException, IOException, HttpException {
+		int count = 0;
+		long[] deletedIDs = local.findDeleted();
+		
+		try {
+			Log.i(TAG, "Remotely removing " + deletedIDs.length + " deleted resource(s) (if not changed)");
+			for (long id : deletedIDs)
+				try {
+					Resource res = local.findById(id, false);
+					if (res.getName() != null)	// is this resource even present remotely?
+						try {
+							remote.delete(res);
+						} catch(NotFoundException e) {
+							Log.i(TAG, "Locally-deleted resource has already been removed from server");
+						} catch(PreconditionFailedException e) {
+							Log.i(TAG, "Locally-deleted resource has been changed on the server in the meanwhile");
+						}
+					
+					// always delete locally so that the record with the DELETED flag doesn't cause another deletion attempt
+					local.delete(res);
+					
+					count++;
+				} catch (RecordNotFoundException e) {
+					Log.wtf(TAG, "Couldn't read locally-deleted record", e);
+				}
+		} finally {
+			local.commit();
+		}
+		return count;
+	}
+	
+	private int pushNew() throws URISyntaxException, LocalStorageException, IOException, HttpException {
+		int count = 0;
+		long[] newIDs = local.findNew();
+		Log.i(TAG, "Uploading " + newIDs.length + " new resource(s) (if not existing)");
+		try {
+			for (long id : newIDs)
+				try {
+					Resource res = local.findById(id, true);
+					String eTag = remote.add(res);
+					if (eTag != null)
+						local.updateETag(res, eTag);
+					local.clearDirty(res);
+					count++;
+				} catch(PreconditionFailedException e) {
+					Log.i(TAG, "Didn't overwrite existing resource with other content");
+				} catch (ValidationException e) {
+					Log.e(TAG, "Couldn't create entity for adding: " + e.toString());
+				} catch (RecordNotFoundException e) {
+					Log.wtf(TAG, "Couldn't read new record", e);
+				}
+		} finally {
+			local.commit();
+		}
+		return count;
+	}
+	
+	private int pushDirty() throws URISyntaxException, LocalStorageException, IOException, HttpException {
+		int count = 0;
+		long[] dirtyIDs = local.findUpdated();
+		Log.i(TAG, "Uploading " + dirtyIDs.length + " modified resource(s) (if not changed)");
+		try {
+			for (long id : dirtyIDs) {
+				try {
+					Resource res = local.findById(id, true);
+					String eTag = remote.update(res);
+					if (eTag != null)
+						local.updateETag(res, eTag);
+					local.clearDirty(res);
+					count++;
+				} catch(PreconditionFailedException e) {
+					Log.i(TAG, "Locally changed resource has been changed on the server in the meanwhile");
+				} catch (ValidationException e) {
+					Log.e(TAG, "Couldn't create entity for updating: " + e.toString());
+				} catch (RecordNotFoundException e) {
+					Log.e(TAG, "Couldn't read dirty record", e);
+				}
+			}
+		} finally {
+			local.commit();
+		}
+		return count;
+	}
+	
+	private int pullNew(Resource[] resourcesToAdd) throws URISyntaxException, LocalStorageException, IOException, HttpException, DavException {
+		int count = 0;
+		Log.i(TAG, "Fetching " + resourcesToAdd.length + " new remote resource(s)");
+		
+		for (Resource[] resources : ArrayUtils.partition(resourcesToAdd, MAX_MULTIGET_RESOURCES))
+			for (Resource res : remote.multiGet(resources)) {
+				Log.d(TAG, "Adding " + res.getName());
+				local.add(res);
+				local.commit();
+				count++;
+			}
+		return count;
+	}
+	
+	private int pullChanged(Resource[] resourcesToUpdate) throws URISyntaxException, LocalStorageException, IOException, HttpException, DavException {
+		int count = 0;
+		Log.i(TAG, "Fetching " + resourcesToUpdate.length + " updated remote resource(s)");
+		
+		for (Resource[] resources : ArrayUtils.partition(resourcesToUpdate, MAX_MULTIGET_RESOURCES))
+			for (Resource res : remote.multiGet(resources)) {
+				Log.i(TAG, "Updating " + res.getName());
+				local.updateByRemoteName(res);
+				local.commit();
+				count++;
+			}
+		return count;
+	}
+
+}

app/src/main/java/at/bitfire/davdroid/syncadapter/WebDavResourceAdapter.java

@@ -0,0 +1,62 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.syncadapter;
+
+import java.util.List;
+
+import android.content.Context;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.BaseAdapter;
+import android.widget.TextView;
+import at.bitfire.davdroid.webdav.WebDavResource;
+
+public class WebDavResourceAdapter extends BaseAdapter {
+	protected int viewId;
+	protected LayoutInflater inflater;
+	WebDavResource[] items;
+
+	public WebDavResourceAdapter(Context context, int textViewResourceId, List<WebDavResource> objects) {
+		viewId = textViewResourceId;
+		inflater = LayoutInflater.from(context);
+		items = objects.toArray(new WebDavResource[0]);
+	}
+
+	@Override
+	public View getView(int position, View view, ViewGroup parent) {
+		WebDavResource item = items[position];
+		View itemView = (View)inflater.inflate(viewId, null);
+		
+		TextView textName = (TextView) itemView.findViewById(android.R.id.text1);
+		textName.setText(item.getDisplayName());
+		
+		TextView textDescription = (TextView) itemView.findViewById(android.R.id.text2);
+		String description = item.getDescription();
+		if (description == null)
+			description = item.getLocation().getPath();
+		textDescription.setText(description);
+		
+		return itemView;
+	}
+
+	@Override
+	public int getCount() {
+		return items.length;
+	}
+
+	@Override
+	public Object getItem(int position) {
+		return items[position];
+	}
+
+	@Override
+	public long getItemId(int position) {
+		return position;
+	}
+}

app/src/main/java/at/bitfire/davdroid/webdav/DavAddressbookMultiget.java

@@ -0,0 +1,21 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import org.simpleframework.xml.Namespace;
+import org.simpleframework.xml.NamespaceList;
+import org.simpleframework.xml.Root;
+
+@Root(name="addressbook-multiget")
+@NamespaceList({
+	@Namespace(reference="DAV:"),
+	@Namespace(prefix="CD",reference="urn:ietf:params:xml:ns:carddav")
+})
+@Namespace(prefix="CD",reference="urn:ietf:params:xml:ns:carddav")
+public class DavAddressbookMultiget extends DavMultiget {
+}

app/src/main/java/at/bitfire/davdroid/webdav/DavCalendarMultiget.java

@@ -0,0 +1,21 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import org.simpleframework.xml.Namespace;
+import org.simpleframework.xml.NamespaceList;
+import org.simpleframework.xml.Root;
+
+@Root(name="calendar-multiget")
+@NamespaceList({
+	@Namespace(reference="DAV:"),
+	@Namespace(prefix="C",reference="urn:ietf:params:xml:ns:caldav")
+})
+@Namespace(prefix="C",reference="urn:ietf:params:xml:ns:caldav")
+public class DavCalendarMultiget extends DavMultiget {
+}

app/src/main/java/at/bitfire/davdroid/webdav/DavException.java

@@ -0,0 +1,25 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+public class DavException extends Exception {
+	private static final long serialVersionUID = -2118919144443165706L;
+	
+	final private static String prefix = "Invalid DAV response: ";
+	
+	/* used to indiciate DAV protocol errors */
+	
+	
+	public DavException(String message) {
+		super(prefix + message);
+	}
+	
+	public DavException(String message, Throwable ex) {
+		super(prefix + message, ex);
+	}
+}

app/src/main/java/at/bitfire/davdroid/webdav/DavHref.java

@@ -0,0 +1,26 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import org.simpleframework.xml.Namespace;
+import org.simpleframework.xml.Root;
+import org.simpleframework.xml.Text;
+
+@Root(name="href")
+@Namespace(prefix="D",reference="DAV:")
+public class DavHref {
+	@Text
+	String href;
+	
+	DavHref() {
+	}
+	
+	public DavHref(String href) {
+		this.href = href;
+	}
+}

app/src/main/java/at/bitfire/davdroid/webdav/DavHttpClient.java

@@ -0,0 +1,70 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import android.util.Log;
+import at.bitfire.davdroid.Constants;
+import org.apache.http.client.config.RequestConfig;
+import org.apache.http.config.Registry;
+import org.apache.http.config.RegistryBuilder;
+import org.apache.http.conn.socket.ConnectionSocketFactory;
+import org.apache.http.conn.socket.PlainConnectionSocketFactory;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.impl.client.HttpClientBuilder;
+import org.apache.http.impl.client.HttpClients;
+import org.apache.http.impl.conn.ManagedHttpClientConnectionFactory;
+import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
+
+import java.lang.reflect.Method;
+
+
+public class DavHttpClient {
+	private final static String TAG = "davdroid.DavHttpClient";
+	
+	private final static RequestConfig defaultRqConfig;
+	private final static Registry<ConnectionSocketFactory> socketFactoryRegistry;
+		
+	static {
+		socketFactoryRegistry =	RegistryBuilder.<ConnectionSocketFactory> create()
+				.register("http", PlainConnectionSocketFactory.getSocketFactory())
+				.register("https", TlsSniSocketFactory.INSTANCE)
+				.build();
+		
+		// use request defaults from AndroidHttpClient
+		defaultRqConfig = RequestConfig.copy(RequestConfig.DEFAULT)
+				.setConnectTimeout(20*1000)
+				.setSocketTimeout(45*1000)
+				.setStaleConnectionCheckEnabled(false)
+				.build();
+	}
+
+
+	public static CloseableHttpClient create(boolean disableCompression, boolean logTraffic) {
+		PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager(socketFactoryRegistry);
+		// limits per DavHttpClient (= per DavSyncAdapter extends AbstractThreadedSyncAdapter)
+		connectionManager.setMaxTotal(3);				// max.  3 connections in total
+		connectionManager.setDefaultMaxPerRoute(2);		// max.  2 connections per host
+
+		HttpClientBuilder builder = HttpClients.custom()
+				.useSystemProperties()
+				.setConnectionManager(connectionManager)
+				.setDefaultRequestConfig(defaultRqConfig)
+				.setRetryHandler(DavHttpRequestRetryHandler.INSTANCE)
+				.setRedirectStrategy(DavRedirectStrategy.INSTANCE)
+				.setUserAgent("DAVdroid/" + Constants.APP_VERSION)
+				.disableCookieManagement();
+		
+		if (Log.isLoggable("Wire", Log.DEBUG)) {
+			Log.i(TAG, "Wire logging active, disabling HTTP compression");
+			builder = builder.disableContentCompression();
+		}
+
+        return builder.build();
+	}
+
+}

app/src/main/java/at/bitfire/davdroid/webdav/DavHttpRequestRetryHandler.java

@@ -0,0 +1,35 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import java.util.Locale;
+
+import org.apache.commons.lang.ArrayUtils;
+
+import org.apache.http.HttpRequest;
+import org.apache.http.impl.client.DefaultHttpRequestRetryHandler;
+
+public class DavHttpRequestRetryHandler extends DefaultHttpRequestRetryHandler {
+	final static DavHttpRequestRetryHandler INSTANCE = new DavHttpRequestRetryHandler();
+	
+	// see http://www.iana.org/assignments/http-methods/http-methods.xhtml
+	private final static String idempotentMethods[] = {
+		"DELETE", "GET", "HEAD", "MKCALENDAR", "MKCOL", "OPTIONS", "PROPFIND", "PROPPATCH",
+		"PUT", "REPORT", "SEARCH", "TRACE"
+	};
+
+    public DavHttpRequestRetryHandler() {
+        super(/* retry count */ 3, /* retry already sent requests? */ false);
+    }
+
+    //@Override
+    protected boolean handleAsIdempotent(final HttpRequest request) {
+        final String method = request.getRequestLine().getMethod().toUpperCase(Locale.ROOT);
+        return ArrayUtils.contains(idempotentMethods, method);
+    }
+}

app/src/main/java/at/bitfire/davdroid/webdav/DavIncapableException.java

@@ -0,0 +1,18 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+public class DavIncapableException extends DavException {
+	private static final long serialVersionUID = -7199786680939975667L;
+	
+	/* used to indicate that the server doesn't support DAV */
+	
+	public DavIncapableException(String msg) {
+		super(msg);
+	}
+}

app/src/main/java/at/bitfire/davdroid/webdav/DavMultiget.java

@@ -0,0 +1,48 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.simpleframework.xml.Element;
+import org.simpleframework.xml.ElementList;
+import org.simpleframework.xml.Order;
+
+@Order(elements={"prop","href"})
+public class DavMultiget {
+	public enum Type {
+		ADDRESS_BOOK,
+		CALENDAR
+	}
+	
+	@Element
+	DavProp prop;
+	
+	@ElementList(inline=true)
+	List<DavHref> hrefs;
+	
+	
+	public static DavMultiget newRequest(Type type, String names[]) {
+		DavMultiget multiget = (type == Type.ADDRESS_BOOK) ? new DavAddressbookMultiget() : new DavCalendarMultiget(); 
+		
+		multiget.prop = new DavProp();
+		multiget.prop.getetag = new DavProp.GetETag();
+		
+		if (type == Type.ADDRESS_BOOK)
+			multiget.prop.addressData = new DavProp.AddressData();
+		else if (type == Type.CALENDAR)
+			multiget.prop.calendarData = new DavProp.CalendarData();
+
+		multiget.hrefs = new ArrayList<DavHref>(names.length);
+		for (String name : names)
+			multiget.hrefs.add(new DavHref(name));
+		
+		return multiget;
+	}
+}

app/src/main/java/at/bitfire/davdroid/webdav/DavMultistatus.java

@@ -0,0 +1,21 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import java.util.List;
+
+import org.simpleframework.xml.ElementList;
+import org.simpleframework.xml.Namespace;
+import org.simpleframework.xml.Root;
+
+@Namespace(reference="DAV:")
+@Root(strict=false)
+public class DavMultistatus {
+	@ElementList(inline=true,entry="response",required=false)
+	List<DavResponse> response;
+}

app/src/main/java/at/bitfire/davdroid/webdav/DavNoContentException.java

@@ -0,0 +1,18 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+public class DavNoContentException extends DavException {
+	private static final long serialVersionUID = 6256645020350945477L;
+	
+	private final static String message = "HTTP response entity (content) expected but not received";
+
+	public DavNoContentException() {
+		super(message);
+	}
+}

app/src/main/java/at/bitfire/davdroid/webdav/DavNoMultiStatusException.java

@@ -0,0 +1,18 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+public class DavNoMultiStatusException extends DavException {
+	private static final long serialVersionUID = -3600405724694229828L;
+	
+	private final static String message = "207 Multi-Status expected but not received";
+	
+	public DavNoMultiStatusException() {
+		super(message);
+	}
+}

app/src/main/java/at/bitfire/davdroid/webdav/DavProp.java

@@ -0,0 +1,211 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import java.util.List;
+
+import lombok.Getter;
+
+import org.simpleframework.xml.Attribute;
+import org.simpleframework.xml.Element;
+import org.simpleframework.xml.ElementList;
+import org.simpleframework.xml.Namespace;
+import org.simpleframework.xml.Root;
+import org.simpleframework.xml.Text;
+
+@Namespace(prefix="D",reference="DAV:")
+@Root(strict=false)
+public class DavProp {
+	
+	/* RFC 4918 WebDAV */
+	
+	@Element(required=false)
+	ResourceType resourcetype;
+	
+	@Element(required=false)
+	DisplayName displayname;
+	
+	@Element(required=false)
+	GetCTag getctag;
+	
+	@Element(required=false)
+	GetETag getetag;
+	
+	@Root(strict=false)
+	public static class ResourceType {
+		@Element(required=false)
+		@Getter private Collection collection;
+		public static class Collection { }
+		
+		@Element(required=false)
+		@Getter private Addressbook addressbook;
+		@Namespace(prefix="CD",reference="urn:ietf:params:xml:ns:carddav")
+		public static class Addressbook { }
+		
+		@Element(required=false)
+		@Getter private Calendar calendar;
+		@Namespace(prefix="C",reference="urn:ietf:params:xml:ns:caldav")
+		public static class Calendar { }
+	}
+	
+	public static class DisplayName {
+		@Text(required=false)
+		@Getter private String displayName;
+	}
+	
+	@Namespace(prefix="CS",reference="http://calendarserver.org/ns/")
+	public static class GetCTag {
+		@Text(required=false)
+		@Getter private String CTag;
+	}
+	
+	public static class GetETag {
+		@Text(required=false)
+		@Getter private String ETag;
+	}
+	
+	
+	/* RFC 5397 WebDAV Current Principal Extension */
+	
+	@Element(required=false,name="current-user-principal")
+	CurrentUserPrincipal currentUserPrincipal;
+
+	public static class CurrentUserPrincipal {
+		@Element(required=false)
+		@Getter private DavHref href;
+	}
+	
+	
+	/* RFC 3744 WebDAV Access Control Protocol */
+	
+	@ElementList(required=false,name="current-user-privilege-set",entry="privilege")
+	List<Privilege> currentUserPrivilegeSet;
+	
+	public static class Privilege {
+		@Element(required=false)
+		@Getter private PrivAll all;
+		
+		@Element(required=false)
+		@Getter private PrivBind bind;
+		
+		@Element(required=false)
+		@Getter private PrivUnbind unbind;
+		
+		@Element(required=false)
+		@Getter private PrivWrite write;
+		
+		@Element(required=false,name="write-content")
+		@Getter private PrivWriteContent writeContent;
+		
+		public static class PrivAll { }
+		public static class PrivBind { }
+		public static class PrivUnbind { }
+		public static class PrivWrite { }
+		public static class PrivWriteContent { }
+	}
+
+	
+
+	/* RFC 4791 CalDAV, RFC 6352 CardDAV */
+	
+	@Element(required=false,name="addressbook-home-set")
+	AddressbookHomeSet addressbookHomeSet;
+	
+	@Element(required=false,name="calendar-home-set")
+	CalendarHomeSet calendarHomeSet;
+
+	@Element(required=false,name="addressbook-description")
+	AddressbookDescription addressbookDescription;
+
+	@Namespace(prefix="CD",reference="urn:ietf:params:xml:ns:carddav")
+	@ElementList(required=false,name="supported-address-data",entry="address-data-type")
+	List<AddressDataType> supportedAddressData;
+	
+	@Element(required=false,name="calendar-description")
+	CalendarDescription calendarDescription;
+	
+	@Element(required=false,name="calendar-color")
+	CalendarColor calendarColor;
+	
+	@Element(required=false,name="calendar-timezone")
+	CalendarTimezone calendarTimezone;
+	
+	@Namespace(prefix="C",reference="urn:ietf:params:xml:ns:caldav")
+	@ElementList(required=false,name="supported-calendar-component-set",entry="comp")
+	List<Comp> supportedCalendarComponentSet;
+	
+	@Element(name="address-data",required=false)
+	AddressData addressData;
+
+	@Element(name="calendar-data",required=false)
+	CalendarData calendarData;
+
+	
+	@Namespace(prefix="CD",reference="urn:ietf:params:xml:ns:carddav")
+	public static class AddressbookHomeSet {
+		@Element(required=false)
+		@Getter private DavHref href;
+	}
+	
+	@Namespace(prefix="C",reference="urn:ietf:params:xml:ns:caldav")
+	public static class CalendarHomeSet {
+		@Element(required=false)
+		@Getter private DavHref href;
+	}
+	
+	@Namespace(prefix="CD",reference="urn:ietf:params:xml:ns:carddav")
+	public static class AddressbookDescription {
+		@Text(required=false)
+		@Getter private String description;
+	}
+	
+	@Namespace(prefix="CD",reference="urn:ietf:params:xml:ns:carddav")
+	public static class AddressDataType {
+		@Attribute(name="content-type")
+		@Getter private String contentType;
+		
+		@Attribute
+		@Getter private String version;
+	}
+	
+	@Namespace(prefix="C",reference="urn:ietf:params:xml:ns:caldav")
+	public static class CalendarDescription {
+		@Text(required=false)
+		@Getter private String description;
+	}
+	
+	@Namespace(prefix="A",reference="http://apple.com/ns/ical/")
+	public static class CalendarColor {
+		@Text(required=false)
+		@Getter private String color;
+	}
+	
+	@Namespace(prefix="C",reference="urn:ietf:params:xml:ns:caldav")
+	public static class CalendarTimezone {
+		@Text(required=false)
+		@Getter private String timezone;
+	}
+	
+	@Namespace(prefix="C",reference="urn:ietf:params:xml:ns:caldav")
+	public static class Comp {
+		@Attribute
+		@Getter String name;
+	}
+
+	@Namespace(prefix="CD",reference="urn:ietf:params:xml:ns:carddav")
+	public static class AddressData {
+		@Text(required=false)
+		@Getter String vcard;
+	}
+	
+	@Namespace(prefix="C",reference="urn:ietf:params:xml:ns:caldav")
+	public static class CalendarData {
+		@Text(required=false)
+		@Getter String ical;
+	}
+}

app/src/main/java/at/bitfire/davdroid/webdav/DavPropfind.java

@@ -0,0 +1,19 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import org.simpleframework.xml.Element;
+import org.simpleframework.xml.Namespace;
+import org.simpleframework.xml.Root;
+
+@Namespace(reference="DAV:")
+@Root(name="propfind")
+public class DavPropfind {
+	@Element(required=false)
+	protected DavProp prop;
+}

app/src/main/java/at/bitfire/davdroid/webdav/DavPropstat.java

@@ -0,0 +1,20 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import org.simpleframework.xml.Element;
+import org.simpleframework.xml.Root;
+
+@Root(strict=false,name="propstat")
+public class DavPropstat {
+	@Element
+	DavProp prop;
+	
+	@Element
+	String status;
+}

app/src/main/java/at/bitfire/davdroid/webdav/DavRedirectStrategy.java

@@ -0,0 +1,105 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+
+import android.util.Log;
+import at.bitfire.davdroid.URIUtils;
+import org.apache.http.Header;
+import org.apache.http.HttpHost;
+import org.apache.http.HttpRequest;
+import org.apache.http.HttpResponse;
+import org.apache.http.ProtocolException;
+import org.apache.http.RequestLine;
+import org.apache.http.client.RedirectStrategy;
+import org.apache.http.client.methods.HttpUriRequest;
+import org.apache.http.client.methods.RequestBuilder;
+import org.apache.http.client.protocol.HttpClientContext;
+import org.apache.http.protocol.HttpContext;
+
+/**
+ * Custom Redirect Strategy that handles 30x for CalDAV/CardDAV-specific requests correctly
+ */
+public class DavRedirectStrategy implements RedirectStrategy {
+	private final static String TAG = "davdroid.DavRedirectStrategy";
+	final static DavRedirectStrategy INSTANCE = new DavRedirectStrategy();
+	
+	protected final static String REDIRECTABLE_METHODS[] = {
+		"OPTIONS", "GET", "PUT", "DELETE"
+	};
+
+
+	@Override
+	public HttpUriRequest getRedirect(HttpRequest request, HttpResponse response, HttpContext context) throws ProtocolException {
+		RequestLine line = request.getRequestLine();
+
+		String location = getLocation(request, response, context).toString();
+		Log.i(TAG, "Following redirection: " + line.getMethod() + " " + line.getUri() + " -> " + location);
+		
+		return	RequestBuilder.copy(request)
+				.setUri(location)
+				.removeHeaders("Content-Length")	// Content-Length will be set again automatically, if required;
+													// remove it now to avoid duplicate header
+				.build();
+	}
+
+	/**
+	 * Determines whether a response indicates a redirection and if it does, whether to follow this redirection.
+	 * PROPFIND and REPORT must handle redirections explicitely because multi-status processing requires knowledge of the content location.
+	 * @return true for 3xx responses on OPTIONS, GET, PUT, DELETE requests that have a valid Location header; false otherwise
+	 */
+	@Override
+	public boolean isRedirected(HttpRequest request, HttpResponse response, HttpContext context) throws ProtocolException {
+		if (response.getStatusLine().getStatusCode()/100 == 3) {
+			boolean redirectable = false;
+			for (String method : REDIRECTABLE_METHODS)
+				if (method.equalsIgnoreCase(request.getRequestLine().getMethod())) {
+					redirectable = true;
+					break;
+				}
+			return redirectable && getLocation(request, response, context) != null;
+		}
+		return false;
+	}
+
+	/**
+	 * Gets the destination of a redirection 
+	 * @return absolute URL of new location; null if not available
+	 */
+	static URI getLocation(HttpRequest request, HttpResponse response, HttpContext context) {
+		Header locationHdr = response.getFirstHeader("Location");
+		if (locationHdr == null) {
+			Log.e(TAG, "Received redirection without Location header, ignoring");
+			return null;
+		}
+		try {
+			URI location = URIUtils.parseURI(locationHdr.getValue());
+			
+			// some servers don't return absolute URLs as required by RFC 2616
+			if (!location.isAbsolute()) {
+				Log.w(TAG, "Received invalid redirection to relative URL, repairing");
+				URI originalURI = URIUtils.parseURI(request.getRequestLine().getUri());
+				if (!originalURI.isAbsolute()) {
+					final HttpHost target = HttpClientContext.adapt(context).getTargetHost();
+					if (target != null)
+						originalURI = org.apache.http.client.utils.URIUtils.rewriteURI(originalURI, target);
+					else
+						return null;
+				}
+				return originalURI.resolve(location);
+			}
+			return location;
+		} catch (URISyntaxException e) {
+			Log.e(TAG, "Received redirection from/to invalid URI, ignoring", e);
+		}
+		return null;
+	}
+
+}

app/src/main/java/at/bitfire/davdroid/webdav/DavResponse.java

@@ -0,0 +1,25 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import java.util.List;
+
+import lombok.Getter;
+
+import org.simpleframework.xml.Element;
+import org.simpleframework.xml.ElementList;
+import org.simpleframework.xml.Root;
+
+@Root(strict=false)
+public class DavResponse {
+	@Element
+	@Getter DavHref href;
+
+	@ElementList(inline=true)
+	@Getter List<DavPropstat> propstat;
+}

app/src/main/java/at/bitfire/davdroid/webdav/HttpException.java

@@ -0,0 +1,26 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import lombok.Getter;
+
+public class HttpException extends org.apache.http.HttpException {
+	private static final long serialVersionUID = -4805778240079377401L;
+	
+	@Getter private int code;
+	
+	HttpException(int code, String message) {
+		super(message);
+		this.code = code;
+	}
+	
+	public boolean isClientError() {
+		return code/100 == 4;
+	}
+
+}

app/src/main/java/at/bitfire/davdroid/webdav/HttpPropfind.java

@@ -0,0 +1,102 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import java.io.StringWriter;
+import java.net.URI;
+import java.util.LinkedList;
+
+import org.simpleframework.xml.Serializer;
+import org.simpleframework.xml.core.Persister;
+
+import android.util.Log;
+import org.apache.http.client.methods.HttpEntityEnclosingRequestBase;
+import org.apache.http.entity.StringEntity;
+
+public class HttpPropfind extends HttpEntityEnclosingRequestBase {
+	private static final String TAG = "davdroid.HttpPropfind";
+	
+	public final static String METHOD_NAME = "PROPFIND";
+	
+	public enum Mode {
+		CURRENT_USER_PRINCIPAL,
+		HOME_SETS,
+		CARDDAV_COLLECTIONS,
+		CALDAV_COLLECTIONS,
+		COLLECTION_CTAG,
+		MEMBERS_ETAG
+	}
+
+	
+	HttpPropfind(URI uri) {
+		setURI(uri);
+	}
+
+	HttpPropfind(URI uri, Mode mode) {
+		this(uri);
+
+		DavPropfind propfind = new DavPropfind();
+		propfind.prop = new DavProp();
+		
+		int depth = 0;
+		switch (mode) {
+		case CURRENT_USER_PRINCIPAL:
+			propfind.prop.currentUserPrincipal = new DavProp.CurrentUserPrincipal();
+			break;
+		case HOME_SETS:
+			propfind.prop.addressbookHomeSet = new DavProp.AddressbookHomeSet();
+			propfind.prop.calendarHomeSet = new DavProp.CalendarHomeSet();
+			break;
+		case CARDDAV_COLLECTIONS:
+			depth = 1;
+			propfind.prop.displayname = new DavProp.DisplayName();
+			propfind.prop.resourcetype = new DavProp.ResourceType();
+			propfind.prop.currentUserPrivilegeSet = new LinkedList<DavProp.Privilege>();
+			propfind.prop.addressbookDescription = new DavProp.AddressbookDescription();
+			propfind.prop.supportedAddressData = new LinkedList<DavProp.AddressDataType>();
+			break;
+		case CALDAV_COLLECTIONS:
+			depth = 1;
+			propfind.prop.displayname = new DavProp.DisplayName();
+			propfind.prop.resourcetype = new DavProp.ResourceType();
+			propfind.prop.currentUserPrivilegeSet = new LinkedList<DavProp.Privilege>();
+			propfind.prop.calendarDescription = new DavProp.CalendarDescription();
+			propfind.prop.calendarColor = new DavProp.CalendarColor();
+			propfind.prop.calendarTimezone = new DavProp.CalendarTimezone();
+			propfind.prop.supportedCalendarComponentSet = new LinkedList<DavProp.Comp>();
+			break;
+		case COLLECTION_CTAG:
+			propfind.prop.getctag = new DavProp.GetCTag(); 
+			break;
+		case MEMBERS_ETAG:
+			depth = 1;
+			propfind.prop.getctag = new DavProp.GetCTag();
+			propfind.prop.getetag = new DavProp.GetETag();
+			break;
+		}
+		
+		try {
+			Serializer serializer = new Persister();
+			StringWriter writer = new StringWriter();
+			serializer.write(propfind, writer);
+		
+			setHeader("Content-Type", "text/xml; charset=UTF-8");
+			setHeader("Accept", "text/xml");
+			setHeader("Depth", String.valueOf(depth));
+			setEntity(new StringEntity(writer.toString(), "UTF-8"));
+		} catch(Exception ex) {
+			Log.e(TAG, "Couldn't prepare PROPFIND request for " + uri, ex);
+			abort();
+		}
+	}
+
+	@Override
+	public String getMethod() {
+		return METHOD_NAME;
+	}
+}

app/src/main/java/at/bitfire/davdroid/webdav/HttpReport.java

@@ -0,0 +1,46 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import android.util.Log;
+
+import java.io.UnsupportedEncodingException;
+import java.net.URI;
+
+import org.apache.http.client.methods.HttpEntityEnclosingRequestBase;
+import org.apache.http.entity.StringEntity;
+
+public class HttpReport extends HttpEntityEnclosingRequestBase {
+    private static final String TAG = "davdroid.HttpEntityEncloseRequestBase";
+	
+	public final static String METHOD_NAME = "REPORT";
+	
+	
+	HttpReport(URI uri) {
+		setURI(uri);
+	}
+
+	HttpReport(URI uri, String entity) {
+		this(uri);
+		
+		setHeader("Content-Type", "text/xml; charset=UTF-8");
+		setHeader("Accept", "text/xml");
+		setHeader("Depth", "0");
+
+        try {
+            setEntity(new StringEntity(entity, "UTF-8"));
+        } catch (UnsupportedEncodingException e) {
+            Log.wtf(TAG, "String entity doesn't support UTF-8");
+        }
+	}
+
+	@Override
+	public String getMethod() {
+		return METHOD_NAME;
+	}
+}

app/src/main/java/at/bitfire/davdroid/webdav/NotAuthorizedException.java

@@ -0,0 +1,19 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import org.apache.http.HttpStatus;
+
+public class NotAuthorizedException extends HttpException {
+	private static final long serialVersionUID = 2490525047224413586L;
+
+	public NotAuthorizedException(String reason) {
+		super(HttpStatus.SC_UNAUTHORIZED, reason);
+	}
+	
+}

app/src/main/java/at/bitfire/davdroid/webdav/NotFoundException.java

@@ -0,0 +1,18 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import org.apache.http.HttpStatus;
+
+public class NotFoundException extends HttpException {
+	private static final long serialVersionUID = 1565961502781880483L;
+	
+	public NotFoundException(String reason) {
+		super(HttpStatus.SC_NOT_FOUND, reason);
+	}
+}

app/src/main/java/at/bitfire/davdroid/webdav/PreconditionFailedException.java

@@ -0,0 +1,18 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import org.apache.http.HttpStatus;
+
+public class PreconditionFailedException extends HttpException {
+	private static final long serialVersionUID = 102282229174086113L;
+	
+	public PreconditionFailedException(String reason) {
+		super(HttpStatus.SC_PRECONDITION_FAILED, reason);
+	}
+}

app/src/main/java/at/bitfire/davdroid/webdav/TlsSniSocketFactory.java

@@ -0,0 +1,186 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.net.Socket;
+import java.net.UnknownHostException;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.List;
+import javax.net.ssl.HostnameVerifier;
+import javax.net.ssl.SSLPeerUnverifiedException;
+import javax.net.ssl.SSLSession;
+import javax.net.ssl.SSLSocket;
+import org.apache.commons.lang.StringUtils;
+import android.annotation.SuppressLint;
+import android.annotation.TargetApi;
+import android.net.SSLCertificateSocketFactory;
+import android.os.Build;
+import android.util.Log;
+import org.apache.http.HttpHost;
+import org.apache.http.conn.socket.LayeredConnectionSocketFactory;
+import org.apache.http.conn.ssl.BrowserCompatHostnameVerifier;
+import org.apache.http.protocol.HttpContext;
+
+public class TlsSniSocketFactory implements LayeredConnectionSocketFactory {
+	private static final String TAG = "davdroid.SNISocketFactory";
+	
+	final static TlsSniSocketFactory INSTANCE = new TlsSniSocketFactory();
+	
+	private final static SSLCertificateSocketFactory sslSocketFactory =
+			(SSLCertificateSocketFactory)SSLCertificateSocketFactory.getDefault(0);
+	private final static HostnameVerifier hostnameVerifier = new BrowserCompatHostnameVerifier();
+
+	
+	/*
+	For SSL connections without HTTP(S) proxy:
+	   1) createSocket() is called
+	   2) connectSocket() is called which creates a new SSL connection
+	   2a) SNI is set up, and then
+	   2b) the connection is established, hands are shaken and certificate/host name are verified    	 
+	
+	Layered sockets are used with HTTP(S) proxies:
+	   1) a new plain socket is created by the HTTP library
+	   2) the plain socket is connected to http://proxy:8080
+	   3) a CONNECT request is sent to the proxy and the response is parsed
+	   4) now, createLayeredSocket() is called which wraps an SSL socket around the proxy connection,
+	      doing all the set-up and verfication
+	   4a) Because SSLSocket.createSocket(socket, ...) always does a handshake without allowing
+	       to set up SNI before, *** SNI is not available for layered connections *** (unless
+	       active by Android's defaults, which it isn't at the moment).
+	*/
+
+
+	@Override
+	public Socket createSocket(HttpContext context) throws IOException {
+		SSLSocket ssl = (SSLSocket)sslSocketFactory.createSocket();
+		setReasonableEncryption(ssl);
+		return ssl;
+	}
+
+	@Override
+	public Socket connectSocket(int timeout, Socket plain, HttpHost host, InetSocketAddress remoteAddr, InetSocketAddress localAddr, HttpContext context) throws IOException {
+		Log.d(TAG, "Preparing direct SSL connection (without proxy) to " + host);
+		
+		// we'll rather use an SSLSocket directly
+		plain.close();
+		
+		// create a plain SSL socket, but don't do hostname/certificate verification yet
+		SSLSocket ssl = (SSLSocket)sslSocketFactory.createSocket(remoteAddr.getAddress(), host.getPort());
+		setReasonableEncryption(ssl);
+		
+		// connect, set SNI, shake hands, verify, print connection info
+		connectWithSNI(ssl, host.getHostName());
+
+		return ssl;
+	}
+
+	@Override
+	public Socket createLayeredSocket(Socket plain, String host, int port, HttpContext context) throws IOException, UnknownHostException {
+		Log.d(TAG, "Preparing layered SSL connection (over proxy) to " + host);
+		
+		// create a layered SSL socket, but don't do hostname/certificate verification yet
+		SSLSocket ssl = (SSLSocket)sslSocketFactory.createSocket(plain, host, port, true);
+		setReasonableEncryption(ssl);
+
+		// already connected, but verify host name again and print some connection info
+		Log.w(TAG, "Setting SNI/TLSv1.2 will silently fail because the handshake is already done");
+		connectWithSNI(ssl, host);
+
+		return ssl;
+	}
+	
+	
+	@TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
+	private void connectWithSNI(SSLSocket ssl, String host) throws SSLPeerUnverifiedException {
+		// - set SNI host name
+		if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
+			Log.d(TAG, "Using documented SNI with host name " + host);
+			sslSocketFactory.setHostname(ssl, host);
+		} else {
+			Log.d(TAG, "No documented SNI support on Android <4.2, trying with reflection");
+			try {
+				java.lang.reflect.Method setHostnameMethod = ssl.getClass().getMethod("setHostname", String.class);
+				setHostnameMethod.invoke(ssl, host);
+			} catch (Exception e) {
+				Log.w(TAG, "SNI not useable", e);
+			}
+		}
+		
+		// verify hostname and certificate
+		SSLSession session = ssl.getSession();
+		if (!hostnameVerifier.verify(host, session))
+			throw new SSLPeerUnverifiedException("Cannot verify hostname: " + host);
+
+		Log.d(TAG, "Established " + session.getProtocol() + " connection with " + session.getPeerHost() +
+				" using " + session.getCipherSuite());
+	}
+	
+	
+	@SuppressLint("DefaultLocale")
+	private void setReasonableEncryption(SSLSocket ssl) {
+		// set reasonable SSL/TLS settings before the handshake
+		
+		// Android 5.0+ (API level21) provides reasonable default settings
+		// but it still allows SSLv3
+		// https://developer.android.com/about/versions/android-5.0-changes.html#ssl
+
+		// - enable all supported protocols (enables TLSv1.1 and TLSv1.2 on Android <5.0, if available)
+		// - remove all SSL versions (especially SSLv3) because they're insecure now
+		List<String> protocols = new LinkedList<String>();
+		for (String protocol : ssl.getSupportedProtocols())
+			if (!protocol.toUpperCase().contains("SSL"))
+				protocols.add(protocol);
+		Log.v(TAG, "Setting allowed TLS protocols: " + StringUtils.join(protocols, ", "));
+		ssl.setEnabledProtocols(protocols.toArray(new String[0]));
+
+		if (android.os.Build.VERSION.SDK_INT < 21) {	
+			// choose secure cipher suites
+			List<String> allowedCiphers = Arrays.asList(new String[] {
+				// allowed secure ciphers according to NIST.SP.800-52r1.pdf Section 3.3.1 (see docs directory)
+				// TLS 1.2
+				"TLS_RSA_WITH_AES_256_GCM_SHA384",
+				"TLS_RSA_WITH_AES_128_GCM_SHA256",
+				"TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256",
+				"TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256",
+				"TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384",
+				"TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256",
+				"TLS_ECHDE_RSA_WITH_AES_128_GCM_SHA256",
+				// maximum interoperability
+				"TLS_RSA_WITH_3DES_EDE_CBC_SHA",
+				"TLS_RSA_WITH_AES_128_CBC_SHA",
+				// additionally
+				"TLS_RSA_WITH_AES_256_CBC_SHA",
+				"TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA",
+				"TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA",
+				"TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA",
+				"TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA",
+			});
+			
+			List<String> availableCiphers = Arrays.asList(ssl.getSupportedCipherSuites());
+			
+			// preferred ciphers = allowed Ciphers \ availableCiphers
+			HashSet<String> preferredCiphers = new HashSet<String>(allowedCiphers);
+			preferredCiphers.retainAll(availableCiphers);
+			
+			// add preferred ciphers to enabled ciphers
+			// for maximum security, preferred ciphers should *replace* enabled ciphers,
+			// but I guess for the security level of DAVdroid, disabling of insecure
+			// ciphers should be a server-side task
+			HashSet<String> enabledCiphers = preferredCiphers;
+			enabledCiphers.addAll(new HashSet<String>(Arrays.asList(ssl.getEnabledCipherSuites())));
+			
+			Log.v(TAG, "Setting allowed TLS ciphers: " + StringUtils.join(enabledCiphers, ", "));
+			ssl.setEnabledCipherSuites(enabledCiphers.toArray(new String[0]));
+		}
+	}
+	
+}

app/src/main/java/at/bitfire/davdroid/webdav/WebDavResource.java

@@ -0,0 +1,581 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ ******************************************************************************/
+package at.bitfire.davdroid.webdav;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.StringWriter;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Set;
+
+import lombok.Cleanup;
+import lombok.Getter;
+import lombok.ToString;
+
+import org.apache.commons.lang.StringUtils;
+import org.simpleframework.xml.Serializer;
+import org.simpleframework.xml.core.Persister;
+
+import android.util.Log;
+import at.bitfire.davdroid.URIUtils;
+import at.bitfire.davdroid.resource.Event;
+import at.bitfire.davdroid.webdav.DavProp.Comp;
+
+import org.apache.http.Header;
+import org.apache.http.HttpEntity;
+import org.apache.http.HttpHost;
+import org.apache.http.HttpResponse;
+import org.apache.http.HttpStatus;
+import org.apache.http.StatusLine;
+import org.apache.http.auth.AuthScope;
+import org.apache.http.auth.UsernamePasswordCredentials;
+import org.apache.http.client.AuthCache;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpDelete;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.client.methods.HttpOptions;
+import org.apache.http.client.methods.HttpPut;
+import org.apache.http.client.protocol.HttpClientContext;
+import org.apache.http.entity.ByteArrayEntity;
+import org.apache.http.impl.auth.BasicScheme;
+import org.apache.http.impl.client.BasicAuthCache;
+import org.apache.http.impl.client.BasicCredentialsProvider;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.message.BasicLineParser;
+import org.apache.http.util.EntityUtils;
+import ezvcard.VCardVersion;
+
+
+/**
+ * Represents a WebDAV resource (file or collection).
+ * This class is used for all CalDAV/CardDAV communcation.
+ */
+@ToString
+public class WebDavResource {
+	private static final String TAG = "davdroid.WebDavResource";
+	
+	public enum Property {
+		CURRENT_USER_PRINCIPAL,							// resource detection
+		ADDRESSBOOK_HOMESET, CALENDAR_HOMESET,
+		CONTENT_TYPE, READ_ONLY,						// WebDAV (common)
+		DISPLAY_NAME, DESCRIPTION, ETAG,
+		IS_COLLECTION, CTAG,							// collections
+		IS_CALENDAR, COLOR, TIMEZONE, 					// CalDAV
+		IS_ADDRESSBOOK, VCARD_VERSION					// CardDAV
+	}
+	public enum PutMode {
+		ADD_DONT_OVERWRITE,
+		UPDATE_DONT_OVERWRITE
+	}
+
+	// location of this resource
+	@Getter protected URI location;
+	
+	// DAV capabilities (DAV: header) and allowed DAV methods (set for OPTIONS request)
+	protected Set<String>	capabilities = new HashSet<String>(),
+							methods = new HashSet<String>();
+	
+	// DAV properties
+	protected HashMap<Property, String> properties = new HashMap<Property, String>();
+	@Getter protected List<String> supportedComponents;
+	
+	// list of members (only for collections)
+	@Getter protected List<WebDavResource> members;
+
+	// content (available after GET)
+	@Getter protected byte[] content;
+
+	protected CloseableHttpClient httpClient;
+	protected HttpClientContext context;
+	
+	
+	public WebDavResource(CloseableHttpClient httpClient, URI baseURI) {
+		this.httpClient = httpClient;
+		location = baseURI;
+		
+		context = HttpClientContext.create();
+		context.setCredentialsProvider(new BasicCredentialsProvider());
+	}
+	
+	public WebDavResource(CloseableHttpClient httpClient, URI baseURI, String username, String password, boolean preemptive) {
+		this(httpClient, baseURI);
+		
+		HttpHost host = new HttpHost(baseURI.getHost(), baseURI.getPort(), baseURI.getScheme());
+		context.getCredentialsProvider().setCredentials(AuthScope.ANY, new UsernamePasswordCredentials(username, password));
+		
+		if (preemptive) {
+			Log.d(TAG, "Using preemptive authentication (not compatible with Digest auth)");
+			AuthCache authCache = context.getAuthCache();
+			if (authCache == null)
+				authCache = new BasicAuthCache();
+			authCache.put(host, new BasicScheme());
+			context.setAuthCache(authCache);
+		}
+	}
+	
+	WebDavResource(WebDavResource parent) {		// copy constructor: based on existing WebDavResource, reuse settings
+		httpClient = parent.httpClient;
+		context = parent.context;
+		location = parent.location;
+	}
+
+	protected WebDavResource(WebDavResource parent, URI url) {
+		this(parent);
+		location = parent.location.resolve(url);
+	}
+	
+	public WebDavResource(WebDavResource parent, String member) throws URISyntaxException {
+		this(parent);
+		location = parent.location.resolve(URIUtils.parseURI(member));
+	}
+	
+	public WebDavResource(WebDavResource parent, String member, String ETag) throws URISyntaxException {
+		this(parent, member);
+		properties.put(Property.ETAG, ETag);
+	}
+
+	
+
+	/* feature detection */
+
+	public void options() throws URISyntaxException, IOException, HttpException {
+		HttpOptions options = new HttpOptions(location);
+		CloseableHttpResponse response = httpClient.execute(options, context);
+		try {
+			checkResponse(response);
+			
+			Header[] allowHeaders = response.getHeaders("Allow");
+			for (Header allowHeader : allowHeaders)
+				methods.addAll(Arrays.asList(allowHeader.getValue().split(", ?")));
+	
+			Header[] capHeaders = response.getHeaders("DAV");
+			for (Header capHeader : capHeaders)
+				capabilities.addAll(Arrays.asList(capHeader.getValue().split(", ?")));
+		} finally {
+			response.close();
+		}
+	}
+
+	public boolean supportsDAV(String capability) {
+		return capabilities.contains(capability);
+	}
+
+	public boolean supportsMethod(String method) {
+		return methods.contains(method);
+	}
+	
+	
+	/* file hierarchy methods */
+	
+	public String getName() {
+		String[] names = StringUtils.split(location.getPath(), "/");
+		return names[names.length - 1];
+	}
+	
+	
+	/* property methods */
+	
+	public String getCurrentUserPrincipal() {
+		return properties.get(Property.CURRENT_USER_PRINCIPAL);
+	}
+	
+	public String getAddressbookHomeSet() {
+		return properties.get(Property.ADDRESSBOOK_HOMESET);
+	}
+	
+	public String getCalendarHomeSet() {
+		return properties.get(Property.CALENDAR_HOMESET);
+	}
+	
+	public String getContentType() {
+		return properties.get(Property.CONTENT_TYPE);
+	}
+	
+	public void setContentType(String mimeType) {
+		properties.put(Property.CONTENT_TYPE, mimeType);
+	}
+
+	public boolean isReadOnly() {
+		return properties.containsKey(Property.READ_ONLY);
+	}
+	
+	public String getDisplayName() {
+		return properties.get(Property.DISPLAY_NAME);
+	}
+	
+	public String getDescription() {
+		return properties.get(Property.DESCRIPTION);
+	}
+	
+	public String getCTag() {
+		return properties.get(Property.CTAG);
+	}
+	public void invalidateCTag() {
+		properties.remove(Property.CTAG);
+	}
+	
+	public String getETag() {
+		return properties.get(Property.ETAG);
+	}
+
+	public boolean isCalendar() {
+		return properties.containsKey(Property.IS_CALENDAR);
+	}
+	
+	public String getColor() {
+		return properties.get(Property.COLOR);
+	}
+	
+	public String getTimezone() {
+		return properties.get(Property.TIMEZONE);
+	}
+	
+	public boolean isAddressBook() {
+		return properties.containsKey(Property.IS_ADDRESSBOOK);
+	}
+	
+	public VCardVersion getVCardVersion() {
+		String versionStr = properties.get(Property.VCARD_VERSION);
+		return (versionStr != null) ? VCardVersion.valueOfByStr(versionStr) : null;
+	}
+	
+	
+	/* collection operations */
+	
+	public void propfind(HttpPropfind.Mode mode) throws URISyntaxException, IOException, DavException, HttpException {
+		CloseableHttpResponse response = null;
+		
+		// processMultiStatus() requires knowledge of the actual content location,
+		// so we have to handle redirections manually and create a new request for the new location
+		for (int i = context.getRequestConfig().getMaxRedirects(); i > 0; i--) {
+			HttpPropfind propfind = new HttpPropfind(location, mode);
+			response = httpClient.execute(propfind, context);
+			
+			if (response.getStatusLine().getStatusCode()/100 == 3) {
+				location = DavRedirectStrategy.getLocation(propfind, response, context);
+				Log.i(TAG, "Redirection on PROPFIND; trying again at new content URL: " + location);
+				// don't forget to throw away the unneeded response content
+				HttpEntity entity = response.getEntity();
+				if (entity != null) { @Cleanup InputStream content = entity.getContent(); }
+			} else
+				break;		// answer was NOT a redirection, continue
+		}
+		if (response == null)
+			throw new DavNoContentException();
+		
+		try {
+			checkResponse(response);		// will also handle Content-Location
+			processMultiStatus(response);
+		} finally {
+			response.close();
+		}
+	}
+
+	public void multiGet(DavMultiget.Type type, String[] names) throws URISyntaxException, IOException, DavException, HttpException {
+		CloseableHttpResponse response = null;
+		
+		// processMultiStatus() requires knowledge of the actual content location,
+		// so we have to handle redirections manually and create a new request for the new location
+		for (int i = context.getRequestConfig().getMaxRedirects(); i > 0; i--) {
+			// build multi-get XML request 
+			List<String> hrefs = new LinkedList<String>();
+			for (String name : names)
+				hrefs.add(location.resolve(name).getPath());
+			DavMultiget multiget = DavMultiget.newRequest(type, hrefs.toArray(new String[0]));
+			
+			StringWriter writer = new StringWriter();
+			try {
+				Serializer serializer = new Persister();
+				serializer.write(multiget, writer);
+			} catch (Exception ex) {
+				Log.e(TAG, "Couldn't create XML multi-get request", ex);
+				throw new DavException("Couldn't create multi-get request");
+			}
+	
+			// submit REPORT request
+			HttpReport report = new HttpReport(location, writer.toString());
+			response = httpClient.execute(report, context);
+			
+			if (response.getStatusLine().getStatusCode()/100 == 3) {
+				location = DavRedirectStrategy.getLocation(report, response, context);
+				Log.i(TAG, "Redirection on REPORT multi-get; trying again at new content URL: " + location);
+				
+				// don't forget to throw away the unneeded response content
+				HttpEntity entity = response.getEntity();
+				if (entity != null) { @Cleanup InputStream content = entity.getContent(); }
+			} else
+				break;		// answer was NOT a redirection, continue
+		}
+		if (response == null)
+			throw new DavNoContentException();
+		
+		try {
+			checkResponse(response);		// will also handle Content-Location
+			processMultiStatus(response);
+		} finally {
+			response.close();
+		}
+	}
+
+	
+	/* resource operations */
+	
+	public void get(String acceptedType) throws URISyntaxException, IOException, HttpException, DavException {
+		HttpGet get = new HttpGet(location);
+		get.addHeader("Accept", acceptedType);
+		
+		CloseableHttpResponse response = httpClient.execute(get, context);
+		try {
+			checkResponse(response);
+			
+			HttpEntity entity = response.getEntity();
+			if (entity == null)
+				throw new DavNoContentException();
+			
+			content = EntityUtils.toByteArray(entity);
+		} finally {
+			response.close();
+		}
+	}
+	
+	// returns the ETag of the created/updated resource, if available (null otherwise)
+	public String put(byte[] data, PutMode mode) throws URISyntaxException, IOException, HttpException {
+		HttpPut put = new HttpPut(location);
+		put.setEntity(new ByteArrayEntity(data));
+
+		switch (mode) {
+		case ADD_DONT_OVERWRITE:
+			put.addHeader("If-None-Match", "*");
+			break;
+		case UPDATE_DONT_OVERWRITE:
+			put.addHeader("If-Match", (getETag() != null) ? getETag() : "*");
+			break;
+		}
+		
+		if (getContentType() != null)
+			put.addHeader("Content-Type", getContentType());
+
+		CloseableHttpResponse response = httpClient.execute(put, context);
+		try {
+			checkResponse(response);
+
+			Header eTag = response.getLastHeader("ETag");
+			if (eTag != null)
+				return eTag.getValue();
+		} finally {
+			response.close();
+		}
+		
+		return null;
+	}
+	
+	public void delete() throws URISyntaxException, IOException, HttpException {
+		HttpDelete delete = new HttpDelete(location);
+		
+		if (getETag() != null)
+			delete.addHeader("If-Match", getETag());
+		
+		CloseableHttpResponse response = httpClient.execute(delete, context);
+		try {
+			checkResponse(response);
+		} finally {
+			response.close();
+		}
+	}
+	
+
+	/* helpers */
+	
+	protected void checkResponse(HttpResponse response) throws HttpException {
+		checkResponse(response.getStatusLine());
+		
+		// handle Content-Location header (see RFC 4918 5.2 Collection Resources)
+		Header contentLocationHdr = response.getFirstHeader("Content-Location");
+		if (contentLocationHdr != null) {
+			// Content-Location was set, update location correspondingly
+			location = location.resolve(contentLocationHdr.getValue());
+			Log.d(TAG, "Set Content-Location to " + location);
+		}
+	}
+	
+	protected static void checkResponse(StatusLine statusLine) throws HttpException {
+		int code = statusLine.getStatusCode();
+		
+		if (code/100 == 1 || code/100 == 2)		// everything OK
+			return;
+		
+		String reason = code + " " + statusLine.getReasonPhrase();
+		switch (code) {
+		case HttpStatus.SC_UNAUTHORIZED:
+			throw new NotAuthorizedException(reason);
+		case HttpStatus.SC_NOT_FOUND:
+			throw new NotFoundException(reason);
+		case HttpStatus.SC_PRECONDITION_FAILED:
+			throw new PreconditionFailedException(reason);
+		default:
+			throw new HttpException(code, reason);
+		}
+	}
+	
+	protected void processMultiStatus(HttpResponse response) throws IOException, HttpException, DavException {
+		if (response.getStatusLine().getStatusCode() != HttpStatus.SC_MULTI_STATUS)
+			throw new DavNoMultiStatusException();
+		
+		HttpEntity entity = response.getEntity();
+		if (entity == null)
+			throw new DavNoContentException();
+		@Cleanup InputStream content = entity.getContent();
+		
+		DavMultistatus multiStatus;
+		try {
+			Serializer serializer = new Persister();
+			multiStatus = serializer.read(DavMultistatus.class, content, false);
+		} catch (Exception ex) {
+			throw new DavException("Couldn't parse Multi-Status response on REPORT multi-get", ex);
+		}
+
+		if (multiStatus.response == null)	// empty response
+			throw new DavNoContentException();
+		
+		// member list will be built from response
+		List<WebDavResource> members = new LinkedList<WebDavResource>();
+		
+		// iterate through all resources (either ourselves or member)
+		for (DavResponse singleResponse : multiStatus.response) {
+			URI href;
+			try {
+				href = location.resolve(URIUtils.parseURI(singleResponse.getHref().href));
+			} catch(Exception ex) {
+				Log.w(TAG, "Ignoring illegal member URI in multi-status response", ex);
+				continue;
+			}
+			Log.d(TAG, "Processing multi-status element: " + href);
+
+			// process known properties
+			HashMap<Property, String> properties = new HashMap<Property, String>();
+			List<String> supportedComponents = null;
+			byte[] data = null;
+
+			for (DavPropstat singlePropstat : singleResponse.getPropstat()) {
+				StatusLine status = BasicLineParser.parseStatusLine(singlePropstat.status, new BasicLineParser());
+				
+				// ignore information about missing properties etc.
+				if (status.getStatusCode()/100 != 1 && status.getStatusCode()/100 != 2)
+					continue;
+				DavProp prop = singlePropstat.prop;
+
+				if (prop.currentUserPrincipal != null && prop.currentUserPrincipal.getHref() != null)
+					properties.put(Property.CURRENT_USER_PRINCIPAL, prop.currentUserPrincipal.getHref().href);
+				
+				if (prop.currentUserPrivilegeSet != null) {
+					// privilege info available
+					boolean mayAll = false,
+							mayBind = false,
+							mayUnbind = false,
+							mayWrite = false,
+							mayWriteContent = false;
+					for (DavProp.Privilege privilege : prop.currentUserPrivilegeSet) {
+						if (privilege.getAll() != null) mayAll = true;
+						if (privilege.getBind() != null) mayBind = true;
+						if (privilege.getUnbind() != null) mayUnbind = true;
+						if (privilege.getWrite() != null) mayWrite = true;
+						if (privilege.getWriteContent() != null) mayWriteContent = true;
+					}
+					if (!mayAll && !mayWrite && !(mayWriteContent && mayBind && mayUnbind))
+						properties.put(Property.READ_ONLY, "1");
+				}
+				
+				if (prop.addressbookHomeSet != null && prop.addressbookHomeSet.getHref() != null)
+					properties.put(Property.ADDRESSBOOK_HOMESET, URIUtils.ensureTrailingSlash(prop.addressbookHomeSet.getHref().href));
+				
+				if (prop.calendarHomeSet != null && prop.calendarHomeSet.getHref() != null)
+					properties.put(Property.CALENDAR_HOMESET, URIUtils.ensureTrailingSlash(prop.calendarHomeSet.getHref().href));
+				
+				if (prop.displayname != null)
+					properties.put(Property.DISPLAY_NAME, prop.displayname.getDisplayName());
+				
+				if (prop.resourcetype != null) {
+					if (prop.resourcetype.getCollection() != null) {
+						properties.put(Property.IS_COLLECTION, "1");
+						// is a collection, ensure trailing slash
+						href = URIUtils.ensureTrailingSlash(href);
+					}
+					if (prop.resourcetype.getAddressbook() != null) {	// CardDAV collection properties
+						properties.put(Property.IS_ADDRESSBOOK, "1");
+						
+						if (prop.addressbookDescription != null)
+							properties.put(Property.DESCRIPTION, prop.addressbookDescription.getDescription());
+						if (prop.supportedAddressData != null)
+							for (DavProp.AddressDataType dataType : prop.supportedAddressData)
+								if ("text/vcard".equalsIgnoreCase(dataType.getContentType()))
+									// ignore "3.0" as it MUST be supported anyway
+									if ("4.0".equals(dataType.getVersion()))
+										properties.put(Property.VCARD_VERSION, VCardVersion.V4_0.getVersion());
+					}
+					if (prop.resourcetype.getCalendar() != null) {		// CalDAV collection propertioes
+						properties.put(Property.IS_CALENDAR, "1");
+						
+						if (prop.calendarDescription != null)
+							properties.put(Property.DESCRIPTION, prop.calendarDescription.getDescription());
+						
+						if (prop.calendarColor != null)
+							properties.put(Property.COLOR, prop.calendarColor.getColor());
+						
+						if (prop.calendarTimezone != null)
+							try {
+								properties.put(Property.TIMEZONE, Event.TimezoneDefToTzId(prop.calendarTimezone.getTimezone()));
+							} catch(IllegalArgumentException e) {
+							}
+						
+						if (prop.supportedCalendarComponentSet != null) {
+							supportedComponents = new LinkedList<String>();
+							for (Comp component : prop.supportedCalendarComponentSet)
+								supportedComponents.add(component.getName());
+						}
+					}
+				}
+				
+				if (prop.getctag != null)
+					properties.put(Property.CTAG, prop.getctag.getCTag());
+
+				if (prop.getetag != null)
+					properties.put(Property.ETAG, prop.getetag.getETag());
+				
+				if (prop.calendarData != null && prop.calendarData.ical != null)
+					data = prop.calendarData.ical.getBytes();
+				else if (prop.addressData != null && prop.addressData.vcard != null)
+					data = prop.addressData.vcard.getBytes();
+			}
+			
+			// about which resource is this response?
+			if (location.equals(href) || URIUtils.ensureTrailingSlash(location).equals(href)) {	// about ourselves
+				this.properties.putAll(properties);
+				if (supportedComponents != null)
+					this.supportedComponents = supportedComponents;
+				this.content = data;
+				
+			} else {						// about a member
+				WebDavResource member = new WebDavResource(this, href);
+				member.properties = properties;
+				member.supportedComponents = supportedComponents;
+				member.content = data;
+				
+				members.add(member);
+			}
+		}
+		
+		this.members = members;
+	}
+
+}

app/src/main/java/ical4j.properties

@@ -0,0 +1,6 @@
+
+net.fortuna.ical4j.timezone.update.enabled=false
+
+ical4j.unfolding.relaxed=true
+ical4j.parsing.relaxed=true
+ical4j.compatibility.outlook=true