Basic implementation of calendar sync. with common SyncManager

.gitignore

@@ -85,6 +85,8 @@ build/
 # Ignore Gradle GUI config
 gradle-app.setting
 
-
 ### external libs ###
 .svn
+
+# Javadoc
+javadoc/

.gitmodules

@@ -7,3 +7,6 @@
 [submodule "MemorizingTrustManager"]
 	path = MemorizingTrustManager
 	url = https://github.com/ge0rg/MemorizingTrustManager
+[submodule "ical4android"]
+	path = ical4android
+	url = git@gitlab.com:bitfireAT/ical4android.git

app/build.gradle

@@ -50,11 +50,13 @@ configurations.all {
 }
 
 dependencies {
+    compile 'com.google.guava:guava:18.0'
     compile 'dnsjava:dnsjava:2.1.7'
     provided 'org.projectlombok:lombok:1.16.6'
     compile('org.slf4j:slf4j-android:1.7.12')
 
     compile project(':dav4android')
+    compile project(':ical4android')
     compile project(':vcard4android')
 
     compile project(':MemorizingTrustManager')

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

@@ -144,7 +144,7 @@ public class DavResourceFinder {
                                 member.location.toString(),
                                 displayName != null ? displayName.displayName : null,
                                 description != null ? description.description : null,
-                                color != null ? DavUtils.CalDAVtoARGBColor(color.color) : null
+                                color != null ? color.color : null
                         );
 
                         CalendarTimezone tz = (CalendarTimezone)member.properties.get(CalendarTimezone.NAME);

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

@@ -24,7 +24,7 @@ import lombok.Cleanup;
 import lombok.Synchronized;
 
 
-public class LocalAddressBook extends AndroidAddressBook {
+public class LocalAddressBook extends AndroidAddressBook implements LocalCollection {
 
     protected static final String SYNC_STATE_CTAG = "ctag";
 
@@ -39,14 +39,15 @@ public class LocalAddressBook extends AndroidAddressBook {
     /**
      * Returns an array of local contacts, excluding those which have been modified locally (and not uploaded yet).
      */
+    @Override
     public LocalContact[] getAll() throws ContactsStorageException {
-        LocalContact contacts[] = (LocalContact[])queryContacts(null, null);
-        return contacts;
+        return (LocalContact[])queryContacts(null, null);
     }
 
     /**
      * Returns an array of local contacts which have been deleted locally. (DELETED != 0).
      */
+    @Override
     public LocalContact[] getDeleted() throws ContactsStorageException {
         return (LocalContact[])queryContacts(ContactsContract.RawContacts.DELETED + "!=0", null);
     }
@@ -54,6 +55,7 @@ public class LocalAddressBook extends AndroidAddressBook {
     /**
      * Returns an array of local contacts which have been changed locally (DIRTY != 0).
      */
+    @Override
     public LocalContact[] getDirty() throws ContactsStorageException {
         return (LocalContact[])queryContacts(ContactsContract.RawContacts.DIRTY + "!=0", null);
     }
@@ -61,6 +63,7 @@ public class LocalAddressBook extends AndroidAddressBook {
     /**
      * Returns an array of local contacts which don't have a file name yet.
      */
+    @Override
     public LocalContact[] getWithoutFileName() throws ContactsStorageException {
         return (LocalContact[])queryContacts(AndroidContact.COLUMN_FILENAME + " IS NULL", null);
     }
@@ -77,6 +80,7 @@ public class LocalAddressBook extends AndroidAddressBook {
             syncState.clear();
     }
 
+    @Override
     public String getCTag() throws ContactsStorageException {
         synchronized (syncState) {
             readSyncState();
@@ -84,6 +88,7 @@ public class LocalAddressBook extends AndroidAddressBook {
         }
     }
 
+    @Override
     public void setCTag(String cTag) throws ContactsStorageException {
         synchronized (syncState) {
             readSyncState();

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

@@ -0,0 +1,134 @@
+/*
+ * Copyright © 2013 – 2015 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 android.accounts.Account;
+import android.content.ContentProviderClient;
+import android.content.ContentResolver;
+import android.content.ContentValues;
+import android.database.Cursor;
+import android.net.Uri;
+import android.os.RemoteException;
+import android.provider.CalendarContract;
+import android.provider.CalendarContract.Calendars;
+import android.provider.CalendarContract.Events;
+import android.provider.CalendarContract.Reminders;
+
+import com.google.common.base.Joiner;
+
+import at.bitfire.ical4android.AndroidCalendar;
+import at.bitfire.ical4android.AndroidCalendarFactory;
+import at.bitfire.ical4android.CalendarStorageException;
+import at.bitfire.vcard4android.ContactsStorageException;
+import lombok.Cleanup;
+
+public class LocalCalendar extends AndroidCalendar implements LocalCollection {
+
+    public static final int defaultColor = 0xFFC3EA6E;     // "DAVdroid green"
+
+    public static final String COLUMN_CTAG = Calendars.CAL_SYNC1;
+
+    static String[] BASE_INFO_COLUMNS = new String[] {
+            Events._ID,
+            LocalEvent.COLUMN_FILENAME,
+            LocalEvent.COLUMN_ETAG
+    };
+
+    @Override
+    protected String[] eventBaseInfoColumns() {
+        return BASE_INFO_COLUMNS;
+    }
+
+
+    protected LocalCalendar(Account account, ContentProviderClient provider, long id) {
+        super(account, provider, LocalEvent.Factory.INSTANCE, id);
+    }
+
+    public static Uri create(Account account, ContentResolver resolver, ServerInfo.ResourceInfo info) throws CalendarStorageException {
+        @Cleanup("release") ContentProviderClient provider = resolver.acquireContentProviderClient(CalendarContract.AUTHORITY);
+        if (provider == null)
+            throw new CalendarStorageException("Couldn't acquire ContentProviderClient for " + CalendarContract.AUTHORITY);
+
+        ContentValues values = new ContentValues();
+        values.put(Calendars.NAME, info.getURL());
+        values.put(Calendars.CALENDAR_DISPLAY_NAME, info.getTitle());
+        values.put(Calendars.CALENDAR_COLOR, info.color != null ? info.color : defaultColor);
+        values.put(Calendars.CALENDAR_ACCESS_LEVEL, info.readOnly ? Calendars.CAL_ACCESS_READ : Calendars.CAL_ACCESS_OWNER);
+        values.put(Calendars.OWNER_ACCOUNT, account.name);
+        values.put(Calendars.SYNC_EVENTS, 1);
+        if (info.timezone != null) {
+            // TODO parse VTIMEZONE
+            // values.put(Calendars.CALENDAR_TIME_ZONE, DateUtils.findAndroidTimezoneID(info.timezone));
+        }
+        values.put(Calendars.ALLOWED_REMINDERS, Reminders.METHOD_ALERT);
+        values.put(Calendars.ALLOWED_AVAILABILITY, Joiner.on(",").join(Reminders.AVAILABILITY_TENTATIVE, Reminders.AVAILABILITY_FREE, Reminders.AVAILABILITY_BUSY));
+        values.put(Calendars.ALLOWED_ATTENDEE_TYPES, Joiner.on(",").join(CalendarContract.Attendees.TYPE_OPTIONAL, CalendarContract.Attendees.TYPE_REQUIRED, CalendarContract.Attendees.TYPE_RESOURCE));
+        return create(account, provider, values);
+    }
+
+
+    @Override
+    public LocalResource[] getAll() throws CalendarStorageException, ContactsStorageException {
+        return (LocalEvent[])queryEvents(null, null);
+    }
+
+    @Override
+    public LocalEvent[] getDeleted() throws CalendarStorageException {
+        return (LocalEvent[])queryEvents(Events.DELETED + "!=0", null);
+    }
+
+    @Override
+    public LocalEvent[] getWithoutFileName() throws CalendarStorageException {
+        return (LocalEvent[])queryEvents(LocalEvent.COLUMN_FILENAME + " IS NULL", null);
+    }
+
+    @Override
+    public LocalResource[] getDirty() throws CalendarStorageException {
+        return (LocalEvent[])queryEvents(Events.DIRTY + "!=0", null);
+    }
+
+
+    @Override
+    public String getCTag() throws CalendarStorageException {
+        try {
+            @Cleanup Cursor cursor = provider.query(calendarSyncURI(), new String[] { COLUMN_CTAG }, null, null, null);
+            if (cursor != null && cursor.moveToNext())
+                return cursor.getString(0);
+        } catch (RemoteException e) {
+            throw new CalendarStorageException("Couldn't read local (last known) CTag", e);
+        }
+        return null;
+    }
+
+    @Override
+    public void setCTag(String cTag) throws CalendarStorageException, ContactsStorageException {
+        try {
+            ContentValues values = new ContentValues(1);
+            values.put(COLUMN_CTAG, cTag);
+            provider.update(calendarSyncURI(), values, null, null);
+        } catch (RemoteException e) {
+            throw new CalendarStorageException("Couldn't write local (last known) CTag", e);
+        }
+    }
+
+
+    public static class Factory implements AndroidCalendarFactory {
+        public static final Factory INSTANCE = new Factory();
+
+        @Override
+        public AndroidCalendar newInstance(Account account, ContentProviderClient provider, long id) {
+            return new LocalCalendar(account, provider, id);
+        }
+
+        @Override
+        public AndroidCalendar[] newArray(int size) {
+            return new LocalCalendar[size];
+        }
+    }
+}

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

@@ -0,0 +1,27 @@
+/*
+ * Copyright © 2013 – 2015 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 android.provider.ContactsContract;
+
+import at.bitfire.ical4android.CalendarStorageException;
+import at.bitfire.vcard4android.ContactsStorageException;
+
+public interface LocalCollection {
+
+    LocalResource[] getDeleted() throws CalendarStorageException, ContactsStorageException;
+    LocalResource[] getWithoutFileName()  throws CalendarStorageException, ContactsStorageException;
+    LocalResource[] getDirty() throws CalendarStorageException, ContactsStorageException;
+
+    LocalResource[] getAll() throws CalendarStorageException, ContactsStorageException;
+
+    String getCTag() throws CalendarStorageException, ContactsStorageException;
+    void setCTag(String cTag) throws CalendarStorageException, ContactsStorageException;
+
+}

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

@@ -20,7 +20,7 @@ import at.bitfire.vcard4android.Contact;
 import at.bitfire.vcard4android.ContactsStorageException;
 import ezvcard.Ezvcard;
 
-public class LocalContact extends AndroidContact {
+public class LocalContact extends AndroidContact implements LocalResource {
     static {
         Contact.productID = "+//IDN bitfire.at//DAVdroid/" + BuildConfig.VERSION_NAME + " ez-vcard/" + Ezvcard.VERSION;
     }
@@ -39,6 +39,8 @@ public class LocalContact extends AndroidContact {
             values.put(ContactsContract.RawContacts.DIRTY, 0);
             values.put(COLUMN_ETAG, eTag);
             addressBook.provider.update(rawContactSyncURI(), values, null, null);
+
+            this.eTag = eTag;
         } catch (RemoteException e) {
             throw new ContactsStorageException("Couldn't clear dirty flag", e);
         }
@@ -46,10 +48,14 @@ public class LocalContact extends AndroidContact {
 
     public void updateFileNameAndUID(String uid) throws ContactsStorageException {
         try {
-            ContentValues values = new ContentValues(1);
-            values.put(COLUMN_FILENAME, uid + ".vcf");
+            String newFileName = uid + ".vcf";
+
+            ContentValues values = new ContentValues(2);
+            values.put(COLUMN_FILENAME, newFileName);
             values.put(COLUMN_UID, uid);
             addressBook.provider.update(rawContactSyncURI(), values, null, null);
+
+            fileName = newFileName;
         } catch (RemoteException e) {
             throw new ContactsStorageException("Couldn't update UID", e);
         }

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

@@ -0,0 +1,119 @@
+/*
+ * Copyright © 2013 – 2015 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 android.content.ContentProviderOperation;
+import android.content.ContentValues;
+import android.net.Uri;
+import android.os.RemoteException;
+import android.provider.CalendarContract;
+
+import at.bitfire.ical4android.AndroidCalendar;
+import at.bitfire.ical4android.AndroidEvent;
+import at.bitfire.ical4android.AndroidEventFactory;
+import at.bitfire.ical4android.CalendarStorageException;
+import at.bitfire.ical4android.Event;
+import lombok.Getter;
+import lombok.Setter;
+
+public class LocalEvent extends AndroidEvent implements LocalResource {
+
+    static final String COLUMN_FILENAME = CalendarContract.Events.SYNC_DATA1,
+                        COLUMN_ETAG = CalendarContract.Events.SYNC_DATA2,
+                        COLUMN_UID = CalendarContract.Events.UID_2445;
+
+    @Getter protected String fileName;
+    @Getter @Setter protected String eTag;
+
+    public LocalEvent(AndroidCalendar calendar, Event event, String fileName, String eTag) {
+        super(calendar, event);
+        this.fileName = fileName;
+        this.eTag = eTag;
+    }
+
+    protected LocalEvent(AndroidCalendar calendar, long id, ContentValues baseInfo) {
+        super(calendar, id, baseInfo);
+        fileName = baseInfo.getAsString(COLUMN_FILENAME);
+        eTag = baseInfo.getAsString(COLUMN_ETAG);
+    }
+
+
+    /* process LocalEvent-specific fields */
+
+    @Override
+    protected void populateEvent(ContentValues values) {
+        super.populateEvent(values);
+        fileName = values.getAsString(COLUMN_FILENAME);
+        eTag = values.getAsString(COLUMN_ETAG);
+        event.uid = values.getAsString(COLUMN_UID);
+    }
+
+    @Override
+    protected void buildEvent(Event recurrence, ContentProviderOperation.Builder builder) {
+        super.buildEvent(recurrence, builder);
+        builder .withValue(COLUMN_FILENAME, fileName)
+                .withValue(COLUMN_ETAG, eTag)
+                .withValue(COLUMN_UID, event.uid);
+    }
+
+
+    /* custom queries */
+
+    public void updateFileNameAndUID(String uid) throws CalendarStorageException {
+        try {
+            String newFileName = uid + ".ics";
+
+            ContentValues values = new ContentValues(2);
+            values.put(COLUMN_FILENAME, newFileName);
+            values.put(COLUMN_UID, uid);
+            calendar.provider.update(eventSyncURI(), values, null, null);
+
+            fileName = newFileName;
+            if (event != null)
+                event.uid = uid;
+
+        } catch (RemoteException e) {
+            throw new CalendarStorageException("Couldn't update UID", e);
+        }
+    }
+
+    @Override
+    public void clearDirty(String eTag) throws CalendarStorageException {
+        try {
+            ContentValues values = new ContentValues(2);
+            values.put(CalendarContract.Events.DIRTY, 0);
+            values.put(COLUMN_ETAG, eTag);
+            calendar.provider.update(eventSyncURI(), values, null, null);
+
+            this.eTag = eTag;
+        } catch (RemoteException e) {
+            throw new CalendarStorageException("Couldn't update UID", e);
+        }
+    }
+
+
+    static class Factory implements AndroidEventFactory {
+        static final Factory INSTANCE = new Factory();
+
+        @Override
+        public AndroidEvent newInstance(AndroidCalendar calendar, long id, ContentValues baseInfo) {
+            return new LocalEvent(calendar, id, baseInfo);
+        }
+
+        @Override
+        public AndroidEvent newInstance(AndroidCalendar calendar, Event event) {
+            return new LocalEvent(calendar, event, null, null);
+        }
+
+        @Override
+        public AndroidEvent[] newArray(int size) {
+            return new LocalEvent[size];
+        }
+    }
+}

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

@@ -0,0 +1,26 @@
+/*
+ * Copyright © 2013 – 2015 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 at.bitfire.ical4android.CalendarStorageException;
+import at.bitfire.vcard4android.ContactsStorageException;
+
+public interface LocalResource {
+
+    Long getId();
+
+    String getFileName();
+    String getETag();
+
+    int delete() throws CalendarStorageException, ContactsStorageException;
+
+    void updateFileNameAndUID(String uuid) throws CalendarStorageException, ContactsStorageException;
+    void clearDirty(String eTag) throws CalendarStorageException, ContactsStorageException;
+
+}

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

@@ -7,6 +7,8 @@
  */
 package at.bitfire.davdroid.resource;
 
+import com.squareup.okhttp.HttpUrl;
+
 import java.io.Serializable;
 import java.net.MalformedURLException;
 import java.net.URI;
@@ -57,6 +59,7 @@ public class ServerInfo implements Serializable {
 			  description;
 		final Integer color;
 
+        /** full VTIMEZONE definition (not the TZ ID) */
 		String timezone;
 
 
@@ -79,13 +82,9 @@ public class ServerInfo implements Serializable {
 
 		public String getTitle() {
 			if (title == null) {
-				try {
-					java.net.URL url = new java.net.URL(URL);
-					return url.getPath();
-				} catch (MalformedURLException e) {
-					return URL;
-				}
-			} else
+                HttpUrl url = HttpUrl.parse(URL);
+                return url != null ? url.toString() : "–";
+            } else
 				return title;
 		}
 	}

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

@@ -0,0 +1,213 @@
+/*
+ * Copyright © 2013 – 2015 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.content.ContentProviderClient;
+import android.content.ContentValues;
+import android.content.Context;
+import android.content.SyncResult;
+import android.os.Bundle;
+import android.provider.CalendarContract.Calendars;
+import android.text.TextUtils;
+
+import com.google.common.base.Charsets;
+import com.google.common.base.Joiner;
+import com.squareup.okhttp.HttpUrl;
+import com.squareup.okhttp.MediaType;
+import com.squareup.okhttp.RequestBody;
+import com.squareup.okhttp.ResponseBody;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.charset.Charset;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+
+import at.bitfire.dav4android.DavCalendar;
+import at.bitfire.dav4android.DavResource;
+import at.bitfire.dav4android.exception.DavException;
+import at.bitfire.dav4android.exception.HttpException;
+import at.bitfire.dav4android.property.AddressData;
+import at.bitfire.dav4android.property.CalendarColor;
+import at.bitfire.dav4android.property.CalendarData;
+import at.bitfire.dav4android.property.DisplayName;
+import at.bitfire.dav4android.property.GetCTag;
+import at.bitfire.dav4android.property.GetContentType;
+import at.bitfire.dav4android.property.GetETag;
+import at.bitfire.davdroid.ArrayUtils;
+import at.bitfire.davdroid.Constants;
+import at.bitfire.davdroid.resource.LocalCalendar;
+import at.bitfire.davdroid.resource.LocalContact;
+import at.bitfire.davdroid.resource.LocalEvent;
+import at.bitfire.davdroid.resource.LocalResource;
+import at.bitfire.ical4android.AndroidHostInfo;
+import at.bitfire.ical4android.CalendarStorageException;
+import at.bitfire.ical4android.Event;
+import at.bitfire.ical4android.InvalidCalendarException;
+import at.bitfire.vcard4android.Contact;
+import at.bitfire.vcard4android.ContactsStorageException;
+import lombok.Cleanup;
+
+public class CalendarSyncManager extends SyncManager {
+
+    protected static final int
+            MAX_MULTIGET = 30,
+            NOTIFICATION_ID = 2;
+
+    protected AndroidHostInfo hostInfo;
+
+
+    public CalendarSyncManager(Context context, Account account, Bundle extras, ContentProviderClient provider, SyncResult result, LocalCalendar calendar) {
+        super(NOTIFICATION_ID, context, account, extras, provider, result);
+        localCollection = calendar;
+    }
+
+
+    @Override
+    protected void prepare() {
+        Thread.currentThread().setContextClassLoader(context.getClassLoader());
+
+        hostInfo = new AndroidHostInfo(context.getContentResolver());
+
+        collectionURL = HttpUrl.parse(localCalendar().getName());
+        davCollection = new DavCalendar(httpClient, collectionURL);
+    }
+
+    @Override
+    protected void queryCapabilities() throws DavException, IOException, HttpException, CalendarStorageException {
+        davCollection.propfind(0, DisplayName.NAME, CalendarColor.NAME, GetCTag.NAME);
+
+        // update name and color
+        DisplayName pDisplayName = (DisplayName)davCollection.properties.get(DisplayName.NAME);
+        String displayName = (pDisplayName != null && !TextUtils.isEmpty(pDisplayName.displayName)) ?
+                pDisplayName.displayName : collectionURL.toString();
+
+        CalendarColor pColor = (CalendarColor)davCollection.properties.get(CalendarColor.NAME);
+        int color = (pColor != null && pColor.color != null) ? pColor.color : LocalCalendar.defaultColor;
+
+        ContentValues values = new ContentValues(2);
+        Constants.log.info("Setting new calendar name \"" + displayName + "\" and color 0x" + Integer.toHexString(color));
+        values.put(Calendars.CALENDAR_DISPLAY_NAME, displayName);
+        values.put(Calendars.CALENDAR_COLOR, color);
+        localCalendar().update(values);
+    }
+
+    @Override
+    protected RequestBody prepareUpload(LocalResource resource) throws IOException, CalendarStorageException {
+        LocalEvent local = (LocalEvent)resource;
+        return RequestBody.create(
+                DavCalendar.MIME_ICALENDAR,
+                local.getEvent().toStream().toByteArray()
+        );
+    }
+
+    @Override
+    protected void listRemote() throws IOException, HttpException, DavException {
+        // fetch list of remote VEVENTs and build hash table to index file name
+        davCalendar().calendarQuery("VEVENT");
+        remoteResources = new HashMap<>(davCollection.members.size());
+        for (DavResource vCard : davCollection.members) {
+            String fileName = vCard.fileName();
+            Constants.log.debug("Found remote VEVENT: " + fileName);
+            remoteResources.put(fileName, vCard);
+        }
+    }
+
+    @Override
+    protected void downloadRemote() throws IOException, HttpException, DavException, CalendarStorageException {
+        Constants.log.info("Downloading " + toDownload.size() + " events (" + MAX_MULTIGET + " at once)");
+
+        // download new/updated iCalendars from server
+        for (DavResource[] bunch : ArrayUtils.partition(toDownload.toArray(new DavResource[toDownload.size()]), MAX_MULTIGET)) {
+            Constants.log.info("Downloading " + Joiner.on(" + ").join(bunch));
+
+            if (bunch.length == 1) {
+                // only one contact, use GET
+                DavResource remote = bunch[0];
+
+                ResponseBody body = remote.get("text/calendar");
+                String eTag = ((GetETag)remote.properties.get(GetETag.NAME)).eTag;
+
+                @Cleanup InputStream stream = body.byteStream();
+                processVEvent(remote.fileName(), eTag, stream, body.contentType().charset(Charsets.UTF_8));
+
+            } else {
+                // multiple contacts, use multi-get
+                List<HttpUrl> urls = new LinkedList<>();
+                for (DavResource remote : bunch)
+                    urls.add(remote.location);
+                davCalendar().multiget(urls.toArray(new HttpUrl[urls.size()]));
+
+                // process multiget results
+                for (DavResource remote : davCollection.members) {
+                    String eTag;
+                    GetETag getETag = (GetETag)remote.properties.get(GetETag.NAME);
+                    if (getETag != null)
+                        eTag = getETag.eTag;
+                    else
+                        throw new DavException("Received multi-get response without ETag");
+
+                    Charset charset = Charsets.UTF_8;
+                    GetContentType getContentType = (GetContentType)remote.properties.get(GetContentType.NAME);
+                    if (getContentType != null && getContentType.type != null) {
+                        MediaType type = MediaType.parse(getContentType.type);
+                        if (type != null)
+                            charset = type.charset(Charsets.UTF_8);
+                    }
+
+                    CalendarData calendarData = (CalendarData)remote.properties.get(CalendarData.NAME);
+                    if (calendarData == null || calendarData.iCalendar == null)
+                        throw new DavException("Received multi-get response without address data");
+
+                    @Cleanup InputStream stream = new ByteArrayInputStream(calendarData.iCalendar.getBytes());
+                    processVEvent(remote.fileName(), eTag, stream, charset);
+                }
+            }
+        }
+    }
+
+
+    // helpers
+
+    private LocalCalendar localCalendar() { return ((LocalCalendar)localCollection); }
+    private DavCalendar davCalendar() { return (DavCalendar)davCollection; }
+
+    private void processVEvent(String fileName, String eTag, InputStream stream, Charset charset) throws IOException, CalendarStorageException {
+        Event[] events;
+        try {
+            events = Event.fromStream(stream, charset, hostInfo);
+        } catch (InvalidCalendarException e) {
+            Constants.log.error("Received invalid iCalendar, ignoring");
+            return;
+        }
+
+        if (events.length == 1) {
+            Event newData = events[0];
+
+            // delete local event, if it exists
+            LocalEvent localEvent = (LocalEvent)localResources.get(fileName);
+            if (localEvent != null) {
+                Constants.log.info("Updating " + fileName + " in local calendar");
+                localEvent.setETag(eTag);
+                localEvent.update(newData);
+                syncResult.stats.numUpdates++;
+            } else {
+                Constants.log.info("Adding " + fileName + " to local calendar");
+                localEvent = new LocalEvent(localCalendar(), newData, fileName, eTag);
+                localEvent.add();
+                syncResult.stats.numInserts++;
+            }
+        } else
+            Constants.log.error("Received VCALENDAR with not exactly one VEVENT with UID, but without RECURRENCE-ID; ignoring " + fileName);
+    }
+
+}

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

@@ -17,6 +17,11 @@ import android.content.SyncResult;
 import android.os.Bundle;
 import android.os.IBinder;
 
+import at.bitfire.davdroid.Constants;
+import at.bitfire.davdroid.resource.LocalCalendar;
+import at.bitfire.davdroid.resource.LocalContact;
+import at.bitfire.ical4android.CalendarStorageException;
+
 public class CalendarsSyncAdapterService extends Service {
 	private static SyncAdapter syncAdapter;
 
@@ -38,14 +43,25 @@ public class CalendarsSyncAdapterService extends Service {
 	
 
 	private static class SyncAdapter extends AbstractThreadedSyncAdapter {
-
         public SyncAdapter(Context context) {
             super(context, false);
         }
 
         @Override
         public void onPerformSync(Account account, Bundle extras, String authority, ContentProviderClient provider, SyncResult syncResult) {
+            Constants.log.info("Starting calendar sync (" + authority + ")");
+
+            try {
+                for (LocalCalendar calendar : (LocalCalendar[])LocalCalendar.findAll(account, provider, LocalCalendar.Factory.INSTANCE)) {
+                    Constants.log.info("Synchronizing calendar #"  + calendar.getId() + ", URL: " + calendar.getName());
+                    CalendarSyncManager syncManager = new CalendarSyncManager(getContext(), account, extras, provider, syncResult, calendar);
+                    syncManager.performSync();
+                }
+            } catch (CalendarStorageException e) {
+                Constants.log.error("Couldn't get list of local calendars", e);
+            }
 
+            Constants.log.info("Calendar sync complete");
         }
     }
 

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

@@ -22,8 +22,6 @@ import at.bitfire.davdroid.Constants;
 public class ContactsSyncAdapterService extends Service {
 	private static ContactsSyncAdapter syncAdapter;
 
-
-
 	@Override
 	public void onCreate() {
 		if (syncAdapter == null)
@@ -48,12 +46,12 @@ public class ContactsSyncAdapterService extends Service {
 
         @Override
         public void onPerformSync(Account account, Bundle extras, String authority, ContentProviderClient provider, SyncResult syncResult) {
-            Constants.log.info("Starting contacts sync (" + authority + ")");
+            Constants.log.info("Starting address book sync (" + authority + ")");
 
             ContactsSyncManager syncManager = new ContactsSyncManager(getContext(), account, extras, provider, syncResult);
             syncManager.performSync();
 
-            Constants.log.info("Sync complete for authority " + authority);
+            Constants.log.info("Address book sync complete");
         }
 
     }

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

@@ -10,7 +10,6 @@ package at.bitfire.davdroid.syncadapter;
 
 import android.accounts.Account;
 import android.content.ContentProviderClient;
-import android.content.ContentResolver;
 import android.content.Context;
 import android.content.SyncResult;
 import android.os.Bundle;
@@ -29,18 +28,15 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.nio.charset.Charset;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
-import java.util.UUID;
 
 import at.bitfire.dav4android.DavAddressBook;
 import at.bitfire.dav4android.DavResource;
 import at.bitfire.dav4android.exception.DavException;
 import at.bitfire.dav4android.exception.HttpException;
-import at.bitfire.dav4android.exception.PreconditionFailedException;
 import at.bitfire.dav4android.property.AddressData;
 import at.bitfire.dav4android.property.GetCTag;
 import at.bitfire.dav4android.property.GetContentType;
@@ -51,6 +47,7 @@ import at.bitfire.davdroid.Constants;
 import at.bitfire.davdroid.HttpClient;
 import at.bitfire.davdroid.resource.LocalAddressBook;
 import at.bitfire.davdroid.resource.LocalContact;
+import at.bitfire.davdroid.resource.LocalResource;
 import at.bitfire.vcard4android.Contact;
 import at.bitfire.vcard4android.ContactsStorageException;
 import ezvcard.VCardVersion;
@@ -63,17 +60,8 @@ public class ContactsSyncManager extends SyncManager {
             MAX_MULTIGET = 10,
             NOTIFICATION_ID = 1;
 
-    protected HttpUrl addressBookURL;
-    protected DavAddressBook davCollection;
     protected boolean hasVCard4;
 
-    protected LocalAddressBook addressBook;
-    String currentCTag;
-
-    Map<String, LocalContact> localContacts;
-    Map<String, DavResource> remoteContacts;
-    Set<DavResource> toDownload;
-
 
     public ContactsSyncManager(Context context, Account account, Bundle extras, ContentProviderClient provider, SyncResult result) {
         super(NOTIFICATION_ID, context, account, extras, provider, result);
@@ -82,11 +70,11 @@ public class ContactsSyncManager extends SyncManager {
 
     @Override
     protected void prepare() {
-        addressBookURL = HttpUrl.parse(settings.getAddressBookURL());
-        davCollection = new DavAddressBook(httpClient, addressBookURL);
+        collectionURL = HttpUrl.parse(settings.getAddressBookURL());
+        davCollection = new DavAddressBook(httpClient, collectionURL);
 
         // prepare local address book
-        addressBook = new LocalAddressBook(account, provider);
+        localCollection = new LocalAddressBook(account, provider);
     }
 
     @Override
@@ -103,159 +91,23 @@ public class ContactsSyncManager extends SyncManager {
     }
 
     @Override
-    protected void processLocallyDeleted() throws ContactsStorageException {
-        // Remove locally deleted contacts from server (if they have a name, i.e. if they were uploaded before),
-        // but only if they don't have changed on the server. Then finally remove them from the local address book.
-        LocalContact[] localList = addressBook.getDeleted();
-        for (LocalContact local : localList) {
-            final String fileName = local.getFileName();
-            if (!TextUtils.isEmpty(fileName)) {
-                Constants.log.info(fileName + " has been deleted locally -> deleting from server");
-                try {
-                    new DavResource(httpClient, addressBookURL.newBuilder().addPathSegment(fileName).build())
-                            .delete(local.eTag);
-                } catch (IOException | HttpException e) {
-                    Constants.log.warn("Couldn't delete " + fileName + " from server");
-                }
-            } else
-                Constants.log.info("Removing local contact #" + local.getId() + " which has been deleted locally and was never uploaded");
-            local.delete();
-            syncResult.stats.numDeletes++;
-        }
-    }
-
-    @Override
-    protected void processLocallyCreated() throws ContactsStorageException {
-        // assign file names and UIDs to new contacts so that we can use the file name as an index
-        for (LocalContact local : addressBook.getWithoutFileName()) {
-            String uuid = UUID.randomUUID().toString();
-            Constants.log.info("Found local contact #" + local.getId() + " without file name; assigning name UID/name " + uuid + "[.vcf]");
-            local.updateFileNameAndUID(uuid);
-        }
-    }
-
-    @Override
-    protected void uploadDirty() throws ContactsStorageException, IOException, HttpException {
-        // upload dirty contacts
-        for (LocalContact local : addressBook.getDirty()) {
-            final String fileName = local.getFileName();
-
-            DavResource remote = new DavResource(httpClient, addressBookURL.newBuilder().addPathSegment(fileName).build());
-
-            RequestBody vCard = RequestBody.create(
-                    hasVCard4 ? DavAddressBook.MIME_VCARD4 : DavAddressBook.MIME_VCARD3_UTF8,
-                    local.getContact().toStream(hasVCard4 ? VCardVersion.V4_0 : VCardVersion.V3_0).toByteArray()
-            );
-
-            try {
-                if (local.eTag == null) {
-                    Constants.log.info("Uploading new contact " + fileName);
-                    remote.put(vCard, null, true);
-                    // TODO handle 30x
-                } else {
-                    Constants.log.info("Uploading locally modified contact " + fileName);
-                    remote.put(vCard, local.eTag, false);
-                    // TODO handle 30x
-                }
-
-            } catch (PreconditionFailedException e) {
-                Constants.log.info("Contact has been modified on the server before upload, ignoring", e);
-            }
-
-            String eTag = null;
-            GetETag newETag = (GetETag) remote.properties.get(GetETag.NAME);
-            if (newETag != null) {
-                eTag = newETag.eTag;
-                Constants.log.debug("Received new ETag=" + eTag + " after uploading");
-            } else
-                Constants.log.debug("Didn't receive new ETag after uploading, setting to null");
-
-            local.clearDirty(eTag);
-        }
-    }
-
-    @Override
-    protected boolean checkSyncState() throws ContactsStorageException {
-        // check CTag (ignore on manual sync)
-        currentCTag = null;
-        GetCTag getCTag = (GetCTag) davCollection.properties.get(GetCTag.NAME);
-        if (getCTag != null)
-            currentCTag = getCTag.cTag;
-
-        String localCTag = null;
-        if (extras.containsKey(ContentResolver.SYNC_EXTRAS_MANUAL))
-            Constants.log.info("Manual sync, ignoring CTag");
-        else
-            localCTag = addressBook.getCTag();
-
-        if (currentCTag != null && currentCTag.equals(localCTag)) {
-            Constants.log.info("Remote address book didn't change (CTag=" + currentCTag + "), no need to list VCards");
-            return false;
-        } else
-            return true;
+    protected RequestBody prepareUpload(LocalResource resource) throws IOException, ContactsStorageException {
+        LocalContact local = (LocalContact)resource;
+        return RequestBody.create(
+                hasVCard4 ? DavAddressBook.MIME_VCARD4 : DavAddressBook.MIME_VCARD3_UTF8,
+                local.getContact().toStream(hasVCard4 ? VCardVersion.V4_0 : VCardVersion.V3_0).toByteArray()
+        );
     }
 
     @Override
-    protected void listLocal() throws ContactsStorageException {
-        // fetch list of local contacts and build hash table to index file name
-        LocalContact[] localList = addressBook.getAll();
-        localContacts = new HashMap<>(localList.length);
-        for (LocalContact contact : localList) {
-            Constants.log.debug("Found local contact: " + contact.getFileName());
-            localContacts.put(contact.getFileName(), contact);
-        }
-    }
-
-    @Override
-    protected void listRemote() throws IOException, HttpException, DavException, ContactsStorageException {
+    protected void listRemote() throws IOException, HttpException, DavException {
         // fetch list of remote VCards and build hash table to index file name
-        Constants.log.info("Listing remote VCards");
-        davCollection.queryMemberETags();
-        remoteContacts = new HashMap<>(davCollection.members.size());
+        davAddressBook().addressbookQuery();
+        remoteResources = new HashMap<>(davCollection.members.size());
         for (DavResource vCard : davCollection.members) {
             String fileName = vCard.fileName();
             Constants.log.debug("Found remote VCard: " + fileName);
-            remoteContacts.put(fileName, vCard);
-        }
-    }
-
-    @Override
-    protected void compareEntries() throws IOException, HttpException, DavException, ContactsStorageException {
-        /* check which contacts
-           1. are not present anymore remotely -> delete immediately on local side
-           2. updated remotely -> add to downloadNames
-           3. added remotely  -> add to downloadNames
-         */
-        toDownload = new HashSet<>();
-        for (String localName : localContacts.keySet()) {
-            DavResource remote = remoteContacts.get(localName);
-            if (remote == null) {
-                Constants.log.info(localName + " is not on server anymore, deleting");
-                localContacts.get(localName).delete();
-                syncResult.stats.numDeletes++;
-            } else {
-                // contact is still on server, check whether it has been updated remotely
-                GetETag getETag = (GetETag) remote.properties.get(GetETag.NAME);
-                if (getETag == null || getETag.eTag == null)
-                    throw new DavException("Server didn't provide ETag");
-                String localETag = localContacts.get(localName).eTag,
-                        remoteETag = getETag.eTag;
-                if (remoteETag.equals(localETag))
-                    syncResult.stats.numSkippedEntries++;
-                else {
-                    Constants.log.info(localName + " has been changed on server (current ETag=" + remoteETag + ", last known ETag=" + localETag + ")");
-                    toDownload.add(remote);
-                }
-
-                // remote entry has been seen, remove from list
-                remoteContacts.remove(localName);
-            }
-        }
-
-        // add all unseen (= remotely added) remote contacts
-        if (!remoteContacts.isEmpty()) {
-            Constants.log.info("New VCards have been found on the server: " + TextUtils.join(", ", remoteContacts.keySet()));
-            toDownload.addAll(remoteContacts.values());
+            remoteResources.put(fileName, vCard);
         }
     }
 
@@ -264,7 +116,7 @@ public class ContactsSyncManager extends SyncManager {
         Constants.log.info("Downloading " + toDownload.size() + " contacts (" + MAX_MULTIGET + " at once)");
 
         // prepare downloader which may be used to download external resource like contact photos
-        Contact.Downloader downloader = new ResourceDownloader(httpClient, addressBookURL);
+        Contact.Downloader downloader = new ResourceDownloader(httpClient, collectionURL);
 
         // download new/updated VCards from server
         for (DavResource[] bunch : ArrayUtils.partition(toDownload.toArray(new DavResource[toDownload.size()]), MAX_MULTIGET)) {
@@ -278,14 +130,14 @@ public class ContactsSyncManager extends SyncManager {
                 String eTag = ((GetETag) remote.properties.get(GetETag.NAME)).eTag;
 
                 @Cleanup InputStream stream = body.byteStream();
-                processVCard(syncResult, addressBook, localContacts, remote.fileName(), eTag, stream, body.contentType().charset(Charsets.UTF_8), downloader);
+                processVCard(remote.fileName(), eTag, stream, body.contentType().charset(Charsets.UTF_8), downloader);
 
             } else {
                 // multiple contacts, use multi-get
                 List<HttpUrl> urls = new LinkedList<>();
                 for (DavResource remote : bunch)
                     urls.add(remote.location);
-                davCollection.multiget(urls.toArray(new HttpUrl[urls.size()]), hasVCard4);
+                davAddressBook().multiget(urls.toArray(new HttpUrl[urls.size()]), hasVCard4);
 
                 // process multiget results
                 for (DavResource remote : davCollection.members) {
@@ -309,28 +161,25 @@ public class ContactsSyncManager extends SyncManager {
                         throw new DavException("Received multi-get response without address data");
 
                     @Cleanup InputStream stream = new ByteArrayInputStream(addressData.vCard.getBytes());
-                    processVCard(syncResult, addressBook, localContacts, remote.fileName(), eTag, stream, charset, downloader);
+                    processVCard(remote.fileName(), eTag, stream, charset, downloader);
                 }
             }
         }
     }
 
-    @Override
-    protected void saveSyncState() throws ContactsStorageException {
-        /* Save sync state (CTag). It doesn't matter if it has changed during the sync process
-           (for instance, because another client has uploaded changes), because this will simply
-           cause all remote entries to be listed at the next sync. */
-        Constants.log.info("Saving sync state: CTag=" + currentCTag);
-        addressBook.setCTag(currentCTag);
-    }
 
-    private void processVCard(SyncResult syncResult, LocalAddressBook addressBook, Map<String, LocalContact>localContacts, String fileName, String eTag, InputStream stream, Charset charset, Contact.Downloader downloader) throws IOException, ContactsStorageException {
+    // helpers
+
+    private DavAddressBook davAddressBook() { return (DavAddressBook)davCollection; }
+    private LocalAddressBook localAddressBook() { return (LocalAddressBook)localCollection; }
+
+    private void processVCard(String fileName, String eTag, InputStream stream, Charset charset, Contact.Downloader downloader) throws IOException, ContactsStorageException {
         Contact contacts[] = Contact.fromStream(stream, charset, downloader);
         if (contacts.length == 1) {
             Contact newData = contacts[0];
 
             // delete local contact, if it exists
-            LocalContact localContact = localContacts.get(fileName);
+            LocalContact localContact = (LocalContact)localResources.get(fileName);
             if (localContact != null) {
                 Constants.log.info("Updating " + fileName + " in local address book");
                 localContact.eTag = eTag;
@@ -338,7 +187,7 @@ public class ContactsSyncManager extends SyncManager {
                 syncResult.stats.numUpdates++;
             } else {
                 Constants.log.info("Adding " + fileName + " to local address book");
-                localContact = new LocalContact(addressBook, newData, fileName, eTag);
+                localContact = new LocalContact(localAddressBook(), newData, fileName, eTag);
                 localContact.add();
                 syncResult.stats.numInserts++;
             }
@@ -347,8 +196,10 @@ public class ContactsSyncManager extends SyncManager {
     }
 
 
+    // downloader helper class
+
     @RequiredArgsConstructor
-    static class ResourceDownloader implements Contact.Downloader {
+    private static class ResourceDownloader implements Contact.Downloader {
         final HttpClient httpClient;
         final HttpUrl baseUrl;
 

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

@@ -12,20 +12,37 @@ import android.app.Notification;
 import android.app.NotificationManager;
 import android.app.PendingIntent;
 import android.content.ContentProviderClient;
+import android.content.ContentResolver;
 import android.content.Context;
 import android.content.Intent;
 import android.content.SyncResult;
 import android.os.Build;
 import android.os.Bundle;
+import android.text.TextUtils;
+
+import com.squareup.okhttp.HttpUrl;
+import com.squareup.okhttp.RequestBody;
 
 import java.io.IOException;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
 
+import at.bitfire.dav4android.DavResource;
 import at.bitfire.dav4android.exception.DavException;
 import at.bitfire.dav4android.exception.HttpException;
+import at.bitfire.dav4android.exception.PreconditionFailedException;
+import at.bitfire.dav4android.property.GetCTag;
+import at.bitfire.dav4android.property.GetETag;
 import at.bitfire.davdroid.Constants;
 import at.bitfire.davdroid.HttpClient;
 import at.bitfire.davdroid.R;
+import at.bitfire.davdroid.resource.LocalCollection;
+import at.bitfire.davdroid.resource.LocalResource;
 import at.bitfire.davdroid.ui.DebugInfoActivity;
+import at.bitfire.ical4android.CalendarStorageException;
 import at.bitfire.vcard4android.ContactsStorageException;
 
 abstract public class SyncManager {
@@ -38,21 +55,40 @@ abstract public class SyncManager {
                         SYNC_PHASE_CHECK_SYNC_STATE = 5,
                         SYNC_PHASE_LIST_LOCAL = 6,
                         SYNC_PHASE_LIST_REMOTE = 7,
-                        SYNC_PHASE_COMPARE_ENTRIES = 8,
+                        SYNC_PHASE_COMPARE_LOCAL_REMOTE = 8,
                         SYNC_PHASE_DOWNLOAD_REMOTE = 9,
                         SYNC_PHASE_SAVE_SYNC_STATE = 10;
 
-    final NotificationManager notificationManager;
-    final int notificationId;
+    protected final NotificationManager notificationManager;
+    protected final int notificationId;
+
+    protected final Context context;
+    protected final Account account;
+    protected final Bundle extras;
+    protected final ContentProviderClient provider;
+    protected final SyncResult syncResult;
+
+    protected final AccountSettings settings;
+    protected LocalCollection localCollection;
+
+    protected final HttpClient httpClient;
+    protected HttpUrl collectionURL;
+    protected DavResource davCollection;
+
+
+    /** remote CTag at the time of {@link #listRemote()} */
+    protected String remoteCTag = null;
+
+    /** sync-able resources in the local collection, as enumerated by {@link #listLocal()} */
+    protected Map<String, LocalResource> localResources;
+
+    /** sync-able resources in the remote collection, as enumerated by {@link #listRemote()} */
+    protected Map<String, DavResource> remoteResources;
+
+    /** resources which have changed on the server, as determined by {@link #compareLocalRemote()} */
+    protected Set<DavResource> toDownload;
 
-    final Context context;
-    final Account account;
-    final Bundle extras;
-    final ContentProviderClient provider;
-    final SyncResult syncResult;
 
-    final AccountSettings settings;
-    final HttpClient httpClient;
 
     public SyncManager(int notificationId, Context context, Account account, Bundle extras, ContentProviderClient provider, SyncResult syncResult) {
         this.context = context;
@@ -73,35 +109,46 @@ abstract public class SyncManager {
     public void performSync() {
         int syncPhase = SYNC_PHASE_PREPARE;
         try {
+            Constants.log.info("Preparing synchronization");
             prepare();
 
             syncPhase = SYNC_PHASE_QUERY_CAPABILITIES;
+            Constants.log.info("Querying capabilities");
             queryCapabilities();
 
             syncPhase = SYNC_PHASE_PROCESS_LOCALLY_DELETED;
+            Constants.log.info("Processing locally deleted entries");
             processLocallyDeleted();
 
             syncPhase = SYNC_PHASE_PREPARE_LOCALLY_CREATED;
+            Constants.log.info("Processing locally created entries");
             processLocallyCreated();
 
             syncPhase = SYNC_PHASE_UPLOAD_DIRTY;
+            Constants.log.info("Uploading dirty entries");
             uploadDirty();
 
             syncPhase = SYNC_PHASE_CHECK_SYNC_STATE;
+            Constants.log.info("Checking sync state");
             if (checkSyncState()) {
                 syncPhase = SYNC_PHASE_LIST_LOCAL;
+                Constants.log.info("Listing local entries");
                 listLocal();
 
                 syncPhase = SYNC_PHASE_LIST_REMOTE;
+                Constants.log.info("Listing remote entries");
                 listRemote();
 
-                syncPhase = SYNC_PHASE_COMPARE_ENTRIES;
-                compareEntries();
+                syncPhase = SYNC_PHASE_COMPARE_LOCAL_REMOTE;
+                Constants.log.info("Comparing local/remote entries");
+                compareLocalRemote();
 
                 syncPhase = SYNC_PHASE_DOWNLOAD_REMOTE;
+                Constants.log.info("Downloading remote entries");
                 downloadRemote();
 
                 syncPhase = SYNC_PHASE_SAVE_SYNC_STATE;
+                Constants.log.info("Saving sync state");
                 saveSyncState();
             } else
                 Constants.log.info("Remote collection didn't change, skipping remote sync");
@@ -110,8 +157,8 @@ abstract public class SyncManager {
             Constants.log.error("I/O exception during sync, trying again later", e);
             syncResult.stats.numIoExceptions++;
 
-        } catch(HttpException e) {
-            Constants.log.error("HTTP Exception during sync", e);
+        } catch(HttpException|DavException e) {
+            Constants.log.error("HTTP/DAV Exception during sync", e);
             syncResult.stats.numParseExceptions++;
 
             Intent detailsIntent = new Intent(context, DebugInfoActivity.class);
@@ -138,40 +185,188 @@ abstract public class SyncManager {
             }
             notificationManager.notify(account.name, notificationId, notification);
 
-        } catch(DavException e) {
-            // TODO
-        } catch(ContactsStorageException e) {
+        } catch(CalendarStorageException|ContactsStorageException e) {
+            Constants.log.error("Couldn't access local storage", e);
             syncResult.databaseError = true;
         }
-
     }
 
 
     abstract protected void prepare();
 
-    abstract protected void queryCapabilities() throws IOException, HttpException, DavException, ContactsStorageException;
+    abstract protected void queryCapabilities() throws IOException, HttpException, DavException, CalendarStorageException, ContactsStorageException;
+
+    protected void processLocallyDeleted() throws CalendarStorageException, ContactsStorageException {
+        // Remove locally deleted entries from server (if they have a name, i.e. if they were uploaded before),
+        // but only if they don't have changed on the server. Then finally remove them from the local address book.
+        LocalResource[] localList = localCollection.getDeleted();
+        for (LocalResource local : localList) {
+            final String fileName = local.getFileName();
+            if (!TextUtils.isEmpty(fileName)) {
+                Constants.log.info(fileName + " has been deleted locally -> deleting from server");
+                try {
+                    new DavResource(httpClient, collectionURL.newBuilder().addPathSegment(fileName).build())
+                            .delete(local.getETag());
+                } catch (IOException | HttpException e) {
+                    Constants.log.warn("Couldn't delete " + fileName + " from server");
+                }
+            } else
+                Constants.log.info("Removing local record #" + local.getId() + " which has been deleted locally and was never uploaded");
+            local.delete();
+            syncResult.stats.numDeletes++;
+        }
+    }
+
+    protected void processLocallyCreated() throws CalendarStorageException, ContactsStorageException {
+        // assign file names and UIDs to new contacts so that we can use the file name as an index
+        for (LocalResource local : localCollection.getWithoutFileName()) {
+            String uuid = UUID.randomUUID().toString();
+            Constants.log.info("Found local record #" + local.getId() + " without file name; assigning file name/UID based on " + uuid);
+            local.updateFileNameAndUID(uuid);
+        }
+    }
+
+    abstract protected RequestBody prepareUpload(LocalResource resource) throws IOException, CalendarStorageException, ContactsStorageException;
 
-    abstract protected void processLocallyDeleted() throws IOException, HttpException, DavException, ContactsStorageException;
+    protected void uploadDirty() throws IOException, HttpException, CalendarStorageException, ContactsStorageException {
+        // upload dirty contacts
+        for (LocalResource local : localCollection.getDirty()) {
+            final String fileName = local.getFileName();
 
-    abstract protected void processLocallyCreated() throws IOException, HttpException, DavException, ContactsStorageException;
+            DavResource remote = new DavResource(httpClient, collectionURL.newBuilder().addPathSegment(fileName).build());
 
-    abstract protected void uploadDirty() throws IOException, HttpException, DavException, ContactsStorageException;
+            // generate entity to upload (VCard, iCal, whatever)
+            RequestBody body = prepareUpload(local);
+
+            try {
+
+                if (local.getETag() == null) {
+                    Constants.log.info("Uploading new record " + fileName);
+                    remote.put(body, null, true);
+                    // TODO handle 30x
+                } else {
+                    Constants.log.info("Uploading locally modified record " + fileName);
+                    remote.put(body, local.getETag(), false);
+                    // TODO handle 30x
+                }
+
+            } catch (PreconditionFailedException e) {
+                Constants.log.info("Resource has been modified on the server before upload, ignoring", e);
+            }
+
+            String eTag = null;
+            GetETag newETag = (GetETag) remote.properties.get(GetETag.NAME);
+            if (newETag != null) {
+                eTag = newETag.eTag;
+                Constants.log.debug("Received new ETag=" + eTag + " after uploading");
+            } else
+                Constants.log.debug("Didn't receive new ETag after uploading, setting to null");
+
+            local.clearDirty(eTag);
+        }
+    }
 
     /**
      * Checks the current sync state (e.g. CTag) and whether synchronization from remote is required.
-     * @return  true    if the remote collection has changed, i.e. synchronization from remote is required
-     *          false   if the remote collection hasn't changed
+     * @return <ul>
+     *      <li><code>true</code>   if the remote collection has changed, i.e. synchronization from remote is required</li>
+     *      <li><code>false</code>  if the remote collection hasn't changed</li>
+     * </ul>
      */
-    abstract protected boolean checkSyncState() throws IOException, HttpException, DavException, ContactsStorageException;
+    protected boolean checkSyncState() throws CalendarStorageException, ContactsStorageException {
+        // check CTag (ignore on manual sync)
+        GetCTag getCTag = (GetCTag)davCollection.properties.get(GetCTag.NAME);
+        if (getCTag != null)
+            remoteCTag = getCTag.cTag;
+
+        String localCTag = null;
+        if (extras.containsKey(ContentResolver.SYNC_EXTRAS_MANUAL))
+            Constants.log.info("Manual sync, ignoring CTag");
+        else
+            localCTag = localCollection.getCTag();
+
+        if (remoteCTag != null && remoteCTag.equals(localCTag)) {
+            Constants.log.info("Remote collection didn't change (CTag=" + remoteCTag + "), no need to query children");
+            return false;
+        } else
+            return true;
+    }
 
-    abstract protected void listLocal() throws IOException, HttpException, DavException, ContactsStorageException;
+    /**
+     * Lists all local resources which should be taken into account for synchronization into {@link #localResources}.
+     */
+    protected void listLocal() throws CalendarStorageException, ContactsStorageException {
+        // fetch list of local contacts and build hash table to index file name
+        LocalResource[] localList = localCollection.getAll();
+        localResources = new HashMap<>(localList.length);
+        for (LocalResource resource : localList) {
+            Constants.log.debug("Found local resource: " + resource.getFileName());
+            localResources.put(resource.getFileName(), resource);
+        }
+    }
 
-    abstract protected void listRemote() throws IOException, HttpException, DavException, ContactsStorageException;
+    /**
+     * Lists all members of the remote collection which should be taken into account for synchronization into {@link #remoteResources}.
+     */
+    abstract protected void listRemote() throws IOException, HttpException, DavException;
 
-    abstract protected void compareEntries() throws IOException, HttpException, DavException, ContactsStorageException;
+    /**
+     * Compares {@link #localResources} and {@link #remoteResources} by file name and ETag:
+     * <ul>
+     *     <li>Local resources which are not available in the remote collection (anymore) will be removed.</li>
+     *     <li>Resources whose remote ETag has changed will be added into {@link #toDownload}</li>
+     * </ul>
+     */
+    protected void compareLocalRemote() throws IOException, HttpException, DavException, CalendarStorageException, ContactsStorageException {
+        /* check which contacts
+           1. are not present anymore remotely -> delete immediately on local side
+           2. updated remotely -> add to downloadNames
+           3. added remotely  -> add to downloadNames
+         */
+        toDownload = new HashSet<>();
+        for (String localName : localResources.keySet()) {
+            DavResource remote = remoteResources.get(localName);
+            if (remote == null) {
+                Constants.log.info(localName + " is not on server anymore, deleting");
+                localResources.get(localName).delete();
+                syncResult.stats.numDeletes++;
+            } else {
+                // contact is still on server, check whether it has been updated remotely
+                GetETag getETag = (GetETag) remote.properties.get(GetETag.NAME);
+                if (getETag == null || getETag.eTag == null)
+                    throw new DavException("Server didn't provide ETag");
+                String localETag = localResources.get(localName).getETag(),
+                        remoteETag = getETag.eTag;
+                if (remoteETag.equals(localETag))
+                    syncResult.stats.numSkippedEntries++;
+                else {
+                    Constants.log.info(localName + " has been changed on server (current ETag=" + remoteETag + ", last known ETag=" + localETag + ")");
+                    toDownload.add(remote);
+                }
+
+                // remote entry has been seen, remove from list
+                remoteResources.remove(localName);
+            }
+        }
 
-    abstract protected void downloadRemote() throws IOException, HttpException, DavException, ContactsStorageException;
+        // add all unseen (= remotely added) remote contacts
+        if (!remoteResources.isEmpty()) {
+            Constants.log.info("New VCards have been found on the server: " + TextUtils.join(", ", remoteResources.keySet()));
+            toDownload.addAll(remoteResources.values());
+        }
+    }
 
-    abstract protected void saveSyncState() throws IOException, HttpException, DavException, ContactsStorageException;
+    /**
+     * Downloads the remote resources in {@link #toDownload} and stores them locally.
+     */
+    abstract protected void downloadRemote() throws IOException, HttpException, DavException, ContactsStorageException, CalendarStorageException;
+
+    protected void saveSyncState() throws CalendarStorageException, ContactsStorageException {
+        /* Save sync state (CTag). It doesn't matter if it has changed during the sync process
+           (for instance, because another client has uploaded changes), because this will simply
+           cause all remote entries to be listed at the next sync. */
+        Constants.log.info("Saving CTag=" + remoteCTag);
+        localCollection.setCTag(remoteCTag);
+    }
 
 }

app/src/main/java/at/bitfire/davdroid/ui/setup/AccountDetailsFragment.java

@@ -14,6 +14,7 @@ import android.content.ContentProviderClient;
 import android.content.ContentResolver;
 import android.content.ContentValues;
 import android.os.Bundle;
+import android.provider.CalendarContract;
 import android.provider.ContactsContract;
 import android.text.Editable;
 import android.text.TextWatcher;
@@ -28,13 +29,16 @@ import android.widget.EditText;
 import android.widget.TextView;
 import android.widget.Toast;
 
+import java.util.Calendar;
 import java.util.List;
 
 import at.bitfire.davdroid.Constants;
 import at.bitfire.davdroid.R;
 import at.bitfire.davdroid.resource.LocalAddressBook;
+import at.bitfire.davdroid.resource.LocalCalendar;
 import at.bitfire.davdroid.resource.ServerInfo;
 import at.bitfire.davdroid.syncadapter.AccountSettings;
+import at.bitfire.ical4android.CalendarStorageException;
 import at.bitfire.vcard4android.ContactsStorageException;
 import lombok.Cleanup;
 
@@ -105,14 +109,18 @@ public class AccountDetailsFragment extends Fragment implements TextWatcher {
                 }
             });
 
-			/*addSync(account, CalendarContract.AUTHORITY, serverInfo.getCalendars(), new AddSyncCallback() {
+			addSync(account, CalendarContract.AUTHORITY, serverInfo.getCalendars(), new AddSyncCallback() {
 				@Override
-				public void createLocalCollection(Account account, ServerInfo.ResourceInfo calendar) throws LocalStorageException {
-                    LocalCalendar.create(account, getActivity().getContentResolver(), calendar);
+				public void createLocalCollection(Account account, ServerInfo.ResourceInfo calendar) {
+                    try {
+                        LocalCalendar.create(account, getActivity().getContentResolver(), calendar);
+                    } catch(CalendarStorageException e) {
+                        Constants.log.error("Couldn't create local calendar", e);
+                    }
 				}
 			});
 
-			addSync(account, LocalTaskList.TASKS_AUTHORITY, serverInfo.getTaskLists(), new AddSyncCallback() {
+			/*addSync(account, LocalTaskList.TASKS_AUTHORITY, serverInfo.getTaskLists(), new AddSyncCallback() {
 				@Override
 				public void createLocalCollection(Account account, ServerInfo.ResourceInfo todoList) throws LocalStorageException {
 					LocalTaskList.create(account, getActivity().getContentResolver(), todoList);

app/src/main/java/org/dmfs/provider/tasks/UriFactory.java

@@ -1,56 +0,0 @@
-/*
- * Copyright (C) 2014 Marten Gajda <marten@dmfs.org>
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- * 
- */
-
-package org.dmfs.provider.tasks;
-
-import java.util.HashMap;
-import java.util.Map;
-
-import android.net.Uri;
-
-
-public class UriFactory
-{
-	public final String authority;
-
-	private final Map<String, Uri> mUriMap = new HashMap<String, Uri>(16);
-
-
-	UriFactory(String authority)
-	{
-		this.authority = authority;
-		mUriMap.put((String) null, Uri.parse("content://" + authority));
-	}
-
-
-	void addUri(String path)
-	{
-		mUriMap.put(path, Uri.parse("content://" + authority + "/" + path));
-	}
-
-
-	public Uri getUri()
-	{
-		return mUriMap.get(null);
-	}
-
-
-	public Uri getUri(String path)
-	{
-		return mUriMap.get(path);
-	}
-}

dav4android

@@ -1 +1 @@
-Subproject commit e6c3ee6da90a94d3c77675b8fdd9be7e2d5f83e3
+Subproject commit 7530deb497c7c0ee78a583e7371ef9bfc4458a2e

ical4android

@@ -0,0 +1 @@
+Subproject commit 4e1131ae4607b4220e2d37632fd54a987b633849

settings.gradle

@@ -8,5 +8,7 @@
 
 include ':app'
 include ':dav4android'
+include ':ical4android'
 include ':vcard4android'
+
 include ':MemorizingTrustManager'

vcard4android

@@ -1 +1 @@
-Subproject commit 384de9ec6eab1ac36d875330599b2858ce6ba888
+Subproject commit 53c1695db02cc371369e05cb02a0f1e537ac9eec