From 16770f3612d79b913926ea7b1f27faadb815f970 Mon Sep 17 00:00:00 2001
From: Thomas Bruederli <thomas@roundcube.net>
Date: Wed, 4 Jul 2012 15:57:19 +0200
Subject: [PATCH] Compute the real end date-time of a recurring event for
 caching

---
 .../libkolab/lib/kolab_date_recurrence.php    | 28 ++++++++++++++++++-
 plugins/libkolab/lib/kolab_storage_cache.php  |  3 +-
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/plugins/libkolab/lib/kolab_date_recurrence.php b/plugins/libkolab/lib/kolab_date_recurrence.php
index 95dfedc7..55cc8c35 100644
--- a/plugins/libkolab/lib/kolab_date_recurrence.php
+++ b/plugins/libkolab/lib/kolab_date_recurrence.php
@@ -45,7 +45,7 @@ class kolab_date_recurrence
         $this->next = new Horde_Date($object['start'], kolab_format::$timezone->getName());
 
         if (is_object($object['start']) && is_object($object['end']))
-            $this->duration = $object['end']->diff($object['start']);
+            $this->duration = $object['start']->diff($object['end']);
         else
             $this->duration = new DateInterval('PT' . ($object['end'] - $object['start']) . 'S');
 
@@ -115,6 +115,32 @@ class kolab_date_recurrence
         return false;
     }
 
+    /**
+     * Get the end date of the occurence of this recurrence cycle
+     *
+     * @param string Date limit (where infinite recurrences should abort)
+     * @return mixed Timestamp with end date of the last event or False if recurrence exceeds limit
+     */
+    public function end($limit = 'now +1 year')
+    {
+        if ($this->object['recurrence']['UNTIL'])
+            return $this->object['recurrence']['UNTIL'];
+
+        $limit_time = strtotime($limit);
+        while ($next_start = $this->next_start(true)) {
+            if ($next_start > $limit_time)
+                break;
+        }
+
+        if ($this->next) {
+            $next_end = $this->next->toDateTime();
+            $next_end->add($this->duration);
+            return $next_end->format('U');
+        }
+
+        return false;
+    }
+
     /**
      * Convert the internal structured data into a vcalendar RRULE 2.0 string
      */
diff --git a/plugins/libkolab/lib/kolab_storage_cache.php b/plugins/libkolab/lib/kolab_storage_cache.php
index 969d400c..80a9342a 100644
--- a/plugins/libkolab/lib/kolab_storage_cache.php
+++ b/plugins/libkolab/lib/kolab_storage_cache.php
@@ -514,7 +514,8 @@ class kolab_storage_cache
 
             // extend date range for recurring events
             if ($object['recurrence']) {
-                $sql_data['dtend'] = date('Y-m-d H:i:s', $object['recurrence']['UNTIL'] ?: strtotime('now + 2 years'));
+                $recurrence = new kolab_date_recurrence($object);
+                $sql_data['dtend'] = date('Y-m-d H:i:s', $recurrence->end() ?: strtotime('now +1 year'));
             }
         }
         else if ($objtype == 'task') {