More input checks

* check Android's DURATION, RRULE, RDATE, EXRULE, EXDATE values for empty strings before processing
* catch InvalidArgumentException on invalid RRULE values from Android
* add Depth: 0 to REPORT multi-get requests as required by CalDAV/CardDAV RFCs
* fix crash bug on multi-get responses without content (see issue #113)

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

@@ -209,37 +209,38 @@ public class LocalCalendar extends LocalCollection<Event> {
 			// recurrence
 			try {
 				String duration = cursor.getString(18);
-				if (duration != null)
+				if (duration != null && !duration.isEmpty())
 					e.setDuration(new Duration(new Dur(duration)));
 				
 				String strRRule = cursor.getString(10);
-				if (strRRule != null)
+				if (strRRule != null && !strRRule.isEmpty())
 					e.setRrule(new RRule(strRRule));
 				
 				String strRDate = cursor.getString(11);
-				if (strRDate != null) {
+				if (strRDate != null && !strRDate.isEmpty()) {
 					RDate rDate = new RDate();
 					rDate.setValue(strRDate);
 					e.setRdate(rDate);
 				}
 			
 				String strExRule = cursor.getString(12);
-				if (strExRule != null) {
+				if (strExRule != null && !strExRule.isEmpty()) {
 					ExRule exRule = new ExRule();
 					exRule.setValue(strExRule);
 					e.setExrule(exRule);
 				}
 				
 				String strExDate = cursor.getString(13);
-				if (strExDate != null) {
+				if (strExDate != null && !strExDate.isEmpty()) {
 					// 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.e(TAG, "Couldn't parse recurrence rules, ignoring");
+				Log.w(TAG, "Couldn't parse recurrence rules, ignoring", ex);
+			} catch (IllegalArgumentException ex) {
+				Log.w(TAG, "Invalid recurrence rules, ignoring", ex);
 			}
 
 			// status

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

@@ -23,7 +23,8 @@ public class HttpReport extends HttpEntityEnclosingRequestBase {
 		setURI(uri);
 		
 		setHeader("Content-Type", "text/xml; charset=UTF-8");
-
+		setHeader("Depth", "0");
+		
 		try {
 			setEntity(new StringEntity(entity, "UTF-8"));
 			

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

@@ -437,9 +437,7 @@ public class WebDavResource {
 						
 						if (prop.addressbookDescription != null)
 							properties.put(Property.DESCRIPTION, prop.addressbookDescription.getDescription());
-					} else
+					}
-						properties.remove(Property.IS_ADDRESSBOOK);
-					
 					if (prop.resourcetype.getCalendar() != null) {
 						properties.put(Property.IS_CALENDAR, "1");
 						
@@ -457,19 +455,18 @@ public class WebDavResource {
 							for (DavPropComp component : prop.supportedCalendarComponentSet.components)
 								referenced.supportedComponents.add(component.getName());
 						}
-					} else
+					}
-						referenced.properties.remove(Property.IS_CALENDAR);
 				}
 				
 				if (prop.getctag != null)
-					referenced.properties.put(Property.CTAG, prop.getctag.getCTag());
+					properties.put(Property.CTAG, prop.getctag.getCTag());
 
 				if (prop.getetag != null)
-					referenced.properties.put(Property.ETAG, prop.getetag.getETag());
+					properties.put(Property.ETAG, prop.getetag.getETag());
 				
-				if (prop.calendarData != null)
+				if (prop.calendarData != null && prop.calendarData.ical != null)
 					referenced.content = new ByteArrayInputStream(prop.calendarData.ical.getBytes());
-				else if (prop.addressData != null)
+				else if (prop.addressData != null && prop.addressData.vcard != null)
 					referenced.content = new ByteArrayInputStream(prop.addressData.vcard.getBytes());
 			}
 		}