Update CERN's branch with latest fixes

• Update upstream to 2.6.1
• Caldav: Fix Sabre class names (sometime failing to import due to case sensitive auto loader)
• Caldav: Fix dates sent to backend (don't mix UTC & custom timezone) --- Fixes date errors in events pulled from caldav
• Caldav: Fix etag & uid --- Fixes duplication of events when pushing them

src/backend/caldav/caldav.php

@@ -303,7 +303,11 @@ class BackendCalDAV extends BackendDiff {
         }
         else {
             $etag = "*";
-            $id = sprintf("%s-%s.ics", gmdate("Ymd\THis\Z"), hash("md5", microtime()));
+            if (!empty($message->uid)) {
+                $id = sprintf("%s.ics", $message->uid);
+            } else {
+                $id = sprintf("%s-%s.ics", gmdate("Ymd\THis\Z"), hash("md5", microtime()));
+            }
         }
 
         $url = $this->_caldav_path . substr($folderid, 1) . "/" . $id;
@@ -551,7 +555,7 @@ class BackendCalDAV extends BackendDiff {
         $truncsize = Utils::GetTruncSize($contentparameters->GetTruncation());
         $message = new SyncAppointment();
 
-        $vcal = Sabre\VObject\Reader::read($data, sabre\vobject\reader::OPTION_FORGIVING);
+        $vcal = Sabre\VObject\Reader::read($data, Sabre\VObject\Reader::OPTION_FORGIVING);
         ZLog::Write(LOGLEVEL_WBXML, "VObject vcal: ".print_r($vcal->serialize(), 1));
 
         foreach ($vcal->VEVENT as $vevent) {
@@ -1163,7 +1167,7 @@ class BackendCalDAV extends BackendDiff {
             $vevent->DTSTART['VALUE'] = 'DATE';
         }
         else {
-            $vevent->DTSTART = gmdate("Ymd\THis\Z", $data->starttime);
+            $vevent->DTSTART = $this->DAVDateTimeInTimezone($data->starttime, $tzid);
         }
         if ($tzid != "UTC") {
             $vevent->DTSTART['TZID'] = $tzid;
@@ -1173,7 +1177,7 @@ class BackendCalDAV extends BackendDiff {
             $vevent->DTEND['VALUE'] = 'DATE';
         }
         else {
-            $vevent->DTEND = gmdate("Ymd\THis\Z", $data->endtime);
+            $vevent->DTEND = $this->DAVDateTimeInTimezone($data->endtime, $tzid);
         }
         if ($tzid != "UTC") {
             $vevent->DTEND['TZID'] = $tzid;
@@ -1449,7 +1453,7 @@ class BackendCalDAV extends BackendDiff {
         $truncsize = Utils::GetTruncSize($contentparameters->GetTruncation());
 
         $message = new SyncTask();
-        $vcal = sabre\vobject\reader::read($data, sabre\vobject\reader::OPTION_FORGIVING);
+        $vcal = Sabre\VObject\Reader::read($data, Sabre\VObject\Reader::OPTION_FORGIVING);
         ZLog::Write(LOGLEVEL_DEBUG, "VObject vcal: ".print_r($vcal->serialize(), 1));
 
         foreach ($vcal->VTODO as $vtodo) {
@@ -1920,7 +1924,7 @@ class BackendCalDAV extends BackendDiff {
     private static function DAVDateTimeInTimezone($timestamp, $tzid) {
         $dt = new DateTime('@'.$timestamp);
         $dt->setTimeZone(new DateTimeZone($tzid));
-        return $tzid == 'Z' ? $dt->format('Ymd\THis\Z') : $dt->format('Ymd\THis');
+        return $tzid == 'UTC' ? $dt->format('Ymd\THis\Z') : $dt->format('Ymd\THis');
     }
 
     /**