Improved iCal generation

* move shared code to new iCalendar class
* generate UIDs and file names with "_" instead of "@" to reduce encoding problems (closes #585)
* tasks: validate "start date" and "completed at" time zones

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

@@ -69,11 +69,9 @@ import lombok.NonNull;
 import lombok.Setter;
 
 
-public class Event extends Resource {
+public class Event extends iCalendar {
 	private final static String TAG = "davdroid.Event";
 	
-	private final static TimeZoneRegistry tzRegistry = new DefaultTimeZoneRegistryFactory().createRegistry();
-
 	@Getter @Setter protected RecurrenceId recurrenceId;
 
 	@Getter @Setter protected String summary, location, description;
@@ -97,15 +95,6 @@ public class Event extends Resource {
 
 	@Getter protected List<VAlarm> alarms = new LinkedList<>();
 
-	static {
-		CompatibilityHints.setHintEnabled(CompatibilityHints.KEY_RELAXED_UNFOLDING, true);
-		CompatibilityHints.setHintEnabled(CompatibilityHints.KEY_RELAXED_PARSING, true);
-		CompatibilityHints.setHintEnabled(CompatibilityHints.KEY_OUTLOOK_COMPATIBILITY, true);
-
-		// disable automatic time-zone updates (causes unnecessary network traffic for most people)
-		System.setProperty("net.fortuna.ical4j.timezone.update.enabled", "false");
-	}
-	
 
 	public Event(String name, String ETag) {
 		super(name, ETag);
@@ -116,18 +105,6 @@ public class Event extends Resource {
 	}
 
 
-	@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, AssetDownloader downloader) throws IOException, InvalidResourceException {
@@ -228,12 +205,6 @@ public class Event extends Resource {
 
 	}
 
-
-	@Override
-	public String getMimeType() {
-		return "text/calendar";
-	}
-
 	@Override
 	@SuppressWarnings("unchecked")
 	public ByteArrayOutputStream toEntity() throws IOException {
@@ -334,6 +305,12 @@ public class Event extends Resource {
 	}
 
 
+	// time helpers
+
+	public boolean isAllDay() {
+		return !hasTime(dtStart);
+	}
+
 	public long getDtStartInMillis() {
 		return dtStart.getDate().getTime();
 	}
@@ -372,52 +349,4 @@ public class Event extends Resource {
 	}
 
 
-	// 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 = DateUtils.findAndroidTimezoneID(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/Task.java

@@ -49,7 +49,7 @@ import at.bitfire.davdroid.syncadapter.DavSyncAdapter;
 import lombok.Getter;
 import lombok.Setter;
 
-public class Task extends Resource {
+public class Task extends iCalendar {
 	private final static String TAG = "davdroid.Task";
 
 	@Getter @Setter DateTime createdAt;
@@ -76,13 +76,6 @@ public class Task extends Resource {
 		super(localId, name, ETag);
 	}
 
-	@Override
-	public void initialize() {
-		UidGenerator generator = new UidGenerator(new SimpleHostInfo(DavSyncAdapter.getAndroidID()), String.valueOf(android.os.Process.myPid()));
-		uid = generator.generateUid().getValue();
-		name = uid + ".ics";
-	}
-
 
 	@Override
 	public void parseEntity(InputStream entity, AssetDownloader downloader) throws IOException, InvalidResourceException {
@@ -104,6 +97,10 @@ public class Task extends Resource {
 
 		if (todo.getUid() != null)
 			uid = todo.getUid().getValue();
+		else {
+			Log.w(TAG, "Received VTODO without UID, generating new one");
+			generateUID();
+		}
 
 		if (todo.getCreated() != null)
 			createdAt = todo.getCreated().getDateTime();
@@ -129,20 +126,19 @@ public class Task extends Resource {
 			due = todo.getDue();
 		if (todo.getDuration() != null)
 			duration = todo.getDuration();
-		if (todo.getStartDate() != null)
+		if (todo.getStartDate() != null) {
 			dtStart = todo.getStartDate();
-		if (todo.getDateCompleted() != null)
+			validateTimeZone(dtStart);
+		}
+		if (todo.getDateCompleted() != null) {
 			completedAt = todo.getDateCompleted();
+			validateTimeZone(completedAt);
+		}
 		if (todo.getPercentComplete() != null)
 			percentComplete = todo.getPercentComplete().getPercentage();
 	}
 
 
-	@Override
-	public String getMimeType() {
-		return "text/calendar";
-	}
-
 	@Override
 	public ByteArrayOutputStream toEntity() throws IOException {
 		final net.fortuna.ical4j.model.Calendar ical = new net.fortuna.ical4j.model.Calendar();

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

@@ -0,0 +1,123 @@
+/*
+ * 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.text.format.Time;
+import android.util.Log;
+
+import net.fortuna.ical4j.data.CalendarBuilder;
+import net.fortuna.ical4j.model.DateTime;
+import net.fortuna.ical4j.model.DefaultTimeZoneRegistryFactory;
+import net.fortuna.ical4j.model.TimeZoneRegistry;
+import net.fortuna.ical4j.model.component.VTimeZone;
+import net.fortuna.ical4j.model.parameter.Value;
+import net.fortuna.ical4j.model.property.DateProperty;
+import net.fortuna.ical4j.model.property.DtStart;
+import net.fortuna.ical4j.util.CompatibilityHints;
+import net.fortuna.ical4j.util.SimpleHostInfo;
+import net.fortuna.ical4j.util.UidGenerator;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.StringReader;
+
+import at.bitfire.davdroid.DateUtils;
+import at.bitfire.davdroid.syncadapter.DavSyncAdapter;
+import lombok.Getter;
+
+public abstract class iCalendar extends Resource {
+	static private final String TAG = "DAVdroid.iCal";
+
+	// static ical4j initialization
+	static {
+		CompatibilityHints.setHintEnabled(CompatibilityHints.KEY_RELAXED_UNFOLDING, true);
+		CompatibilityHints.setHintEnabled(CompatibilityHints.KEY_RELAXED_PARSING, true);
+		CompatibilityHints.setHintEnabled(CompatibilityHints.KEY_OUTLOOK_COMPATIBILITY, true);
+
+		// disable automatic time-zone updates (causes unwanted network traffic)
+		System.setProperty("net.fortuna.ical4j.timezone.update.enabled", "false");
+	}
+
+	static protected final TimeZoneRegistry tzRegistry = new DefaultTimeZoneRegistryFactory().createRegistry();
+
+
+	public iCalendar(long localID, String name, String ETag) {
+		super(localID, name, ETag);
+	}
+
+	public iCalendar(String name, String ETag) {
+		super(name, ETag);
+	}
+
+
+	@Override
+	public void initialize() {
+		generateUID();
+		name = uid + ".ics";
+	}
+
+	protected void generateUID() {
+		UidGenerator generator = new UidGenerator(new SimpleHostInfo(DavSyncAdapter.getAndroidID()), String.valueOf(android.os.Process.myPid()));
+		uid = generator.generateUid().getValue().replace("@", "_");
+	}
+
+
+	@Override
+	public String getMimeType() {
+		return "text/calendar";
+	}
+
+
+	// time zone helpers
+
+	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 = DateUtils.findAndroidTimezoneID(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();
+	}
+
+}