Synchronize exceptions of recurring events to the Calendar storage (server to client)

* Event class finds and processes exceptions of recurring events
* workaround for iCloud and other services that provide RECURRENCE-ID as DATETIME even if the original event is an all-day event
* VEvents are generated with all time zone definitions (including time zone definitions of exceptions)

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

@@ -58,8 +58,10 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.StringReader;
 import java.util.Calendar;
+import java.util.HashSet;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.Set;
 import java.util.SimpleTimeZone;
 import java.util.TimeZone;
 
@@ -145,18 +147,43 @@ public class Event extends Resource {
 			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);
 
+		// find master VEVENT (the one that is not an exception, i.e. the one without RECURRENCE-ID)
+		VEvent master = null;
+		for (Object objEvent : events) {
+			VEvent event = (VEvent)objEvent;
+			if (event.getRecurrenceId() == null) {
+				master = event;
+				break;
+			}
+		}
+		if (master == null)
+			throw new InvalidResourceException("No VEVENT without RECURRENCE-ID found");
+		// set event data from master VEVENT
+		fromVEvent(master);
+
+		// find and process exceptions
+		for (Object objEvent : events) {
+			VEvent event = (VEvent)objEvent;
+			if (event.getRecurrenceId() != null) {
+				Event exception = new Event(name, null);
+				exception.fromVEvent(event);
+				exceptions.add(exception);
+			}
+		}
+	}
+
+	protected void fromVEvent(VEvent event) throws InvalidResourceException {
 		if (event.getUid() != null)
 			uid = event.getUid().getValue();
 		else {
 			Log.w(TAG, "Received VEVENT without UID, generating new one");
 			generateUID();
 		}
+		recurrenceId = event.getRecurrenceId();
 
 		if ((dtStart = event.getStartDate()) == null || (dtEnd = event.getEndDate()) == null)
 			throw new InvalidResourceException("Invalid start time/end time/duration");
@@ -205,8 +232,10 @@ public class Event extends Resource {
 		}
 
 		this.alarms = event.getAlarms();
+
 	}
 
+
 	@Override
 	@SuppressWarnings("unchecked")
 	public ByteArrayOutputStream toEntity() throws IOException {
@@ -214,26 +243,38 @@ public class Event extends Resource {
 		ical.getProperties().add(Version.VERSION_2_0);
 		ical.getProperties().add(new ProdId("-//bitfire web engineering//DAVdroid " + Constants.APP_VERSION + " (ical4j 1.0.x)//EN"));
 
-		// "main event" (without exceptions)
+		// "master event" (without exceptions)
 		ComponentList components = ical.getComponents();
-		VEvent mainEvent = toVEvent(this);
+		VEvent master = toVEvent();
-		components.add(mainEvent);
+		components.add(master);
+
+		// remember used time zones
+		Set<net.fortuna.ical4j.model.TimeZone> usedTimeZones = new HashSet<>();
+		if (dtStart != null && dtStart.getTimeZone() != null)
+			usedTimeZones.add(dtStart.getTimeZone());
+		if (dtEnd != null && dtEnd.getTimeZone() != null)
+			usedTimeZones.add(dtEnd.getTimeZone());
 
 		// recurrence exceptions
 		for (Event exception : exceptions) {
-			VEvent vException = toVEvent(exception);
+			// create VEVENT for exception
-			vException.getProperties().add(mainEvent.getProperty(Property.UID));
+			VEvent vException = exception.toVEvent();
+
+			// set UID to UID of master event
+			vException.getProperties().add(master.getProperty(Property.UID));
+
 			components.add(vException);
+
+			// remember used time zones
+			if (exception.dtStart != null && exception.dtStart.getTimeZone() != null)
+				usedTimeZones.add(exception.dtStart.getTimeZone());
+			if (exception.dtEnd != null && exception.dtEnd.getTimeZone() != null)
+				usedTimeZones.add(exception.dtEnd.getTimeZone());
 		}
 
 		// add VTIMEZONE components
-		net.fortuna.ical4j.model.TimeZone
+		for (net.fortuna.ical4j.model.TimeZone timeZone : usedTimeZones)
-			tzStart = (dtStart == null ? null : dtStart.getTimeZone()),
+			ical.getComponents().add(timeZone.getVTimeZone());
-			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();
@@ -245,50 +286,50 @@ public class Event extends Resource {
 		return os;
 	}
 
-	protected static VEvent toVEvent(Event e) {
+	protected VEvent toVEvent() {
 		VEvent event = new VEvent();
 		PropertyList props = event.getProperties();
 
-		if (e.uid != null)
+		if (uid != null)
-			props.add(new Uid(e.uid));
+			props.add(new Uid(uid));
-		if (e.recurrenceId != null)
+		if (recurrenceId != null)
-			props.add(e.recurrenceId);
+			props.add(recurrenceId);
 
-		props.add(e.dtStart);
+		props.add(dtStart);
-		if (e.dtEnd != null)
+		if (dtEnd != null)
-			props.add(e.dtEnd);
+			props.add(dtEnd);
-		if (e.duration != null)
+		if (duration != null)
-			props.add(e.duration);
+			props.add(duration);
 
-		if (e.rrule != null)
+		if (rrule != null)
-			props.add(e.rrule);
+			props.add(rrule);
-		if (e.rdate != null)
+		if (rdate != null)
-			props.add(e.rdate);
+			props.add(rdate);
-		if (e.exrule != null)
+		if (exrule != null)
-			props.add(e.exrule);
+			props.add(exrule);
-		if (e.exdate != null)
+		if (exdate != null)
-			props.add(e.exdate);
+			props.add(exdate);
 
-		if (e.summary != null && !e.summary.isEmpty())
+		if (summary != null && !summary.isEmpty())
-			props.add(new Summary(e.summary));
+			props.add(new Summary(summary));
-		if (e.location != null && !e.location.isEmpty())
+		if (location != null && !location.isEmpty())
-			props.add(new Location(e.location));
+			props.add(new Location(location));
-		if (e.description != null && !e.description.isEmpty())
+		if (description != null && !description.isEmpty())
-			props.add(new Description(e.description));
+			props.add(new Description(description));
 
-		if (e.status != null)
+		if (status != null)
-			props.add(e.status);
+			props.add(status);
-		if (!e.opaque)
+		if (!opaque)
 			props.add(Transp.TRANSPARENT);
 
-		if (e.organizer != null)
+		if (organizer != null)
-			props.add(e.organizer);
+			props.add(organizer);
-		props.addAll(e.attendees);
+		props.addAll(attendees);
 
-		if (e.forPublic != null)
+		if (forPublic != null)
-			event.getProperties().add(e.forPublic ? Clazz.PUBLIC : Clazz.PRIVATE);
+			event.getProperties().add(forPublic ? Clazz.PUBLIC : Clazz.PRIVATE);
 
-		event.getAlarms().addAll(e.alarms);
+		event.getAlarms().addAll(alarms);
 
 		props.add(new LastModified());
 		return event;

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

@@ -35,6 +35,9 @@ 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.TimeZone;
+import net.fortuna.ical4j.model.TimeZoneRegistry;
+import net.fortuna.ical4j.model.TimeZoneRegistryFactory;
 import net.fortuna.ical4j.model.component.VAlarm;
 import net.fortuna.ical4j.model.parameter.Cn;
 import net.fortuna.ical4j.model.parameter.CuType;
@@ -51,6 +54,7 @@ import net.fortuna.ical4j.model.property.RDate;
 import net.fortuna.ical4j.model.property.RRule;
 import net.fortuna.ical4j.model.property.RecurrenceId;
 import net.fortuna.ical4j.model.property.Status;
+import net.fortuna.ical4j.util.TimeZones;
 
 import org.apache.commons.lang.StringUtils;
 
@@ -211,11 +215,12 @@ public class LocalCalendar extends LocalCollection<Event> {
 		// mark (recurring) events with changed/deleted exceptions as dirty
 		String where = entryColumnID() + " IN (SELECT DISTINCT " + Events.ORIGINAL_ID + " FROM events WHERE " +
 			Events.ORIGINAL_ID + " IS NOT NULL AND (" + Events.DIRTY + "=1 OR " + Events.DELETED + "=1))";
-		Log.i(TAG, where);
 		ContentValues dirty = new ContentValues(1);
 		dirty.put(CalendarContract.Events.DIRTY, 1);
 		try {
-			providerClient.update(entriesURI(), dirty, where, null);
+			int rows = providerClient.update(entriesURI(), dirty, where, null);
+			if (rows > 0)
+				Log.d(TAG, rows + " event(s) marked as dirty because of dirty/deleted exceptions");
 		} catch (RemoteException e) {
 			Log.e(TAG, "Couldn't mark events with updated exceptions as dirty", e);
 		}
@@ -540,9 +545,6 @@ public class LocalCalendar extends LocalCollection<Event> {
 
 		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())
@@ -551,6 +553,25 @@ public class LocalCalendar extends LocalCollection<Event> {
 				.withValue(Events.GUESTS_CAN_MODIFY, 1)
 				.withValue(Events.GUESTS_CAN_SEE_GUESTS, 1);
 
+		RecurrenceId recurrenceId = event.getRecurrenceId();
+		if (recurrenceId == null) {
+			// this event is a "master event" (not an exception)
+			builder = builder
+					.withValue(entryColumnRemoteName(), event.getName())
+					.withValue(entryColumnETag(), event.getETag())
+					.withValue(entryColumnUID(), event.getUid());
+		} else {
+			// this event is an exception for a recurring event -> calculate
+			// 1. ORIGINAL_INSTANCE_TIME    when the original instance would have occured (ms UTC)
+			// 2. ORIGINAL_ALL_DAY          was the original instance an all-day event?
+			builder = builder.withValue(Events.ORIGINAL_SYNC_ID, event.getName());
+
+			// ORIGINAL_INSTANCE_TIME and ORIGINAL_ALL_DAY is set in buildExceptions.
+			// It's not possible to use only the RECURRENCE-ID to calculate
+			// ORIGINAL_INSTANCE_TIME and ORIGINAL_ALL_DAY because iCloud sends DATE-TIME
+			// RECURRENCE-IDs even if the original event is an all-day event.
+		}
+
 		boolean recurring = false;
 		if (event.getRrule() != null) {
 			recurring = true;
@@ -612,8 +633,13 @@ public class LocalCalendar extends LocalCollection<Event> {
 	@Override
 	protected void addDataRows(Resource resource, long localID, int backrefIdx) {
 		Event event = (Event)resource;
+		// add exceptions
+		for (Event exception : event.getExceptions())
+			pendingOperations.add(buildException(newDataInsertBuilder(Events.CONTENT_URI, Events.ORIGINAL_ID, localID, backrefIdx), event, exception).build());
+		// add attendees
 		for (Attendee attendee : event.getAttendees())
 			pendingOperations.add(buildAttendee(newDataInsertBuilder(Attendees.CONTENT_URI, Attendees.EVENT_ID, localID, backrefIdx), attendee).build());
+		// add reminders
 		for (VAlarm alarm : event.getAlarms())
 			pendingOperations.add(buildReminder(newDataInsertBuilder(Reminders.CONTENT_URI, Reminders.EVENT_ID, localID, backrefIdx), alarm).build());
 	}
@@ -621,15 +647,55 @@ public class LocalCalendar extends LocalCollection<Event> {
 	@Override
 	protected void removeDataRows(Resource resource) {
 		Event event = (Event)resource;
+		// delete exceptions
+		pendingOperations.add(ContentProviderOperation.newDelete(entriesURI())
+				.withSelection(Events.ORIGINAL_ID + "=?",
+				new String[] { String.valueOf(event.getLocalID()) }).build());
+		// delete attendees
 		pendingOperations.add(ContentProviderOperation.newDelete(syncAdapterURI(Attendees.CONTENT_URI))
 				.withSelection(Attendees.EVENT_ID + "=?",
 				new String[] { String.valueOf(event.getLocalID()) }).build());
+		// delete reminders
 		pendingOperations.add(ContentProviderOperation.newDelete(syncAdapterURI(Reminders.CONTENT_URI))
 				.withSelection(Reminders.EVENT_ID + "=?",
 				new String[] { String.valueOf(event.getLocalID()) }).build());
 	}
 
 
+	protected Builder buildException(Builder builder, Event master, Event exception) {
+		buildEntry(builder, exception);
+		builder.withValue(Events.ORIGINAL_SYNC_ID, exception.getName());
+
+		// Some servers (iCloud, for instance) return RECURRENCE-ID with DATE-TIME even if
+		// the original event is an all-day event. Workaround: determine value of ORIGINAL_ALL_DAY
+		// by original event type (all-day or not) and not by whether RECURRENCE-ID is DATE or DATE-TIME.
+
+		RecurrenceId recurrenceId = exception.getRecurrenceId();
+		Date date = recurrenceId.getDate();
+
+		boolean originalAllDay = master.isAllDay();
+		long originalInstanceTime;
+
+		if (originalAllDay && date instanceof DateTime) {
+			String value = recurrenceId.getValue();
+			if (value.matches("^\\d{8}T\\d{6}$"))
+				try {
+					// no "Z" at the end indicates "local" time
+					// so this is a "local" time, but it should be a ical4j Date without time
+					date = new Date(value.substring(0, 8));
+				} catch (ParseException e) {
+					Log.e(TAG, "Couldn't parse DATE part of DATE-TIME RECURRENCE-ID", e);
+				}
+		}
+		originalInstanceTime = date.getTime();
+		Log.i(TAG, "Original instance time: " + date.getTime()/1000);
+
+		builder.withValue(Events.ORIGINAL_INSTANCE_TIME, originalInstanceTime);
+		builder.withValue(Events.ORIGINAL_ALL_DAY, originalAllDay ? 1 : 0);
+
+		return builder;
+	}
+	
 	@SuppressLint("InlinedApi")
 	protected Builder buildAttendee(Builder builder, Attendee attendee) {
 		Uri member = Uri.parse(attendee.getValue());

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

@@ -350,7 +350,7 @@ public abstract class LocalCollection<T extends Resource> {
 				.build();
 	}
 	
-	protected Builder newDataInsertBuilder(Uri dataUri, String refFieldName, long raw_ref_id, Integer backrefIdx) {
+	protected Builder newDataInsertBuilder(Uri dataUri, String refFieldName, long raw_ref_id, int backrefIdx) {
 		Builder builder = ContentProviderOperation.newInsert(syncAdapterURI(dataUri));
 		if (backrefIdx != -1)
 			return builder.withValueBackReference(refFieldName, backrefIdx);