Add select() method to query objects from cache; Use locks to avoid multiple threads synching the same folder simultaneously

plugins/libkolab/SQL/mysql.sql

@@ -6,7 +6,7 @@
  * @licence GNU AGPL
  **/
 
-CREATE TABLE `kolab_cache` (
+CREATE TABLE IF NOT EXISTS `kolab_cache` (
   `resource` VARCHAR(255) CHARACTER SET ascii NOT NULL,
   `type` VARCHAR(32) CHARACTER SET ascii NOT NULL,
   `msguid` BIGINT UNSIGNED NOT NULL,

plugins/libkolab/lib/kolab_storage_cache.php

@@ -81,6 +81,9 @@ class kolab_storage_cache
         if ($this->synched)
             return;
 
+        // lock synchronization for this folder or wait if locked
+        $this->_sync_lock();
+
         // synchronize IMAP mailbox cache
         $this->imap->folder_sync($this->folder->name);
 
@@ -92,8 +95,9 @@ class kolab_storage_cache
         if ($this->ready) {
             // read cache index
             $sql_result = $this->db->query(
-                "SELECT msguid, uid FROM kolab_cache WHERE resource=?",
-                $this->resource_uri
+                "SELECT msguid, uid FROM kolab_cache WHERE resource=? AND type<>?",
+                $this->resource_uri,
+                'lock'
             );
 
             $old_index = array();
@@ -120,6 +124,9 @@ class kolab_storage_cache
             }
         }
 
+        // remove lock
+        $this->_sync_unlock();
+
         $this->synched = time();
     }
 
@@ -349,6 +356,7 @@ class kolab_storage_cache
                 $this->db->quote($param[2])
             );
         }
+
         return $sql_where;
     }
 
@@ -400,6 +408,11 @@ class kolab_storage_cache
             // database runs in server's timezone so using date() is what we want
             $sql_data['dtstart'] = date('Y-m-d H:i:s', is_object($object['start']) ? $object['start']->format('U') : $object['start']);
             $sql_data['dtend']   = date('Y-m-d H:i:s', is_object($object['end'])   ? $object['end']->format('U')   : $object['end']);
+
+            // extend date range for recurring events
+            if ($object['recurrence']) {
+                $sql_data['dtend'] = date('Y-m-d H:i:s', $object['recurrence']['UNTIL'] ?: strtotime('now + 2 years'));
+            }
         }
 
         if ($object['_formatobj'])
@@ -453,6 +466,61 @@ class kolab_storage_cache
         return $object;
     }
 
+    /**
+     * Check lock record for this folder and wait if locked or set lock
+     */
+    private function _sync_lock()
+    {
+        if (!$this->ready)
+            return;
+
+        $sql_arr = $this->db->fetch_assoc($this->db->query(
+            "SELECT msguid AS locked FROM kolab_cache ".
+            "WHERE resource=? AND type=?",
+            $this->resource_uri,
+            'lock'
+        ));
+
+        // create lock record if not exists
+        if (!$sql_arr) {
+            $this->db->query(
+                "INSERT INTO kolab_cache (resource, type, msguid, uid, data, xml)".
+                " VALUES (?, ?, ?, '', '', '')",
+                $this->resource_uri,
+                'lock',
+                time()
+            );
+        }
+        // wait if locked (expire locks after 10 minutes)
+        else if (intval($sql_arr['locked']) > 0 && (time() - $sql_arr['locked']) < 600) {
+            usleep(500000);
+            return $this->_sync_lock();
+        }
+        // set lock
+        else {
+            $this->db->query(
+                "UPDATE kolab_cache SET msguid=? ".
+                "WHERE resource=? AND type=?",
+                time(),
+                $this->resource_uri,
+                'lock'
+            );
+        }
+    }
+
+    /**
+     * Remove lock for this folder
+     */
+    private function _sync_unlock()
+    {
+        $this->db->query(
+            "UPDATE kolab_cache SET msguid=0 ".
+            "WHERE resource=? AND type=?",
+            $this->resource_uri,
+            'lock'
+        );
+    }
+
     /**
      * Resolve an object UID into an IMAP message UID
      *

plugins/libkolab/lib/kolab_storage_folder.php

@@ -317,6 +317,41 @@ class kolab_storage_folder
     }
 
 
+    /**
+     * Select *some* Kolab objects matching the given query
+     *
+     * @param array Pseudo-SQL query as list of filter parameter triplets
+     *   triplet: array('<colname>', '<comparator>', '<value>')
+     * @return array List of Kolab data objects (each represented as hash array)
+     */
+    public function select($query = array())
+    {
+        // check query argument
+        if (empty($query))
+            return $this->get_objects();
+
+        $type = null;
+        foreach ($query as $i => $param) {
+            if ($param[0] == 'type') {
+                $type = $param[2];
+            }
+            else if (($param[0] == 'dtstart' || $param[0] == 'dtend') && is_numeric($param[2])) {
+              $query[$i][2] = date('Y-m-d H:i:s', $param[2]);
+            }
+        }
+
+        // add type selector if not in $query
+        if (!$type)
+            $query[] = array('type','=',$this->type);
+
+        // synchronize caches
+        $this->cache->synchronize();
+
+        // fetch objects from cache
+        return $this->cache->select($query);
+    }
+
+
     /**
      * Getter for a single Kolab object, identified by its UID
      *

plugins/libkolab/libkolab.php

@@ -63,9 +63,7 @@ class libkolab extends rcube_plugin
      */
     function storage_init($p)
     {
-        $rcmail = rcmail::get_instance();
         $p['fetch_headers'] = trim($p['fetch_headers'] .' X-KOLAB-TYPE');
-
         return $p;
     }