MDL-15553 events_trigger() perf improvement

lib/eventslib.php

@@ -184,6 +184,10 @@ function events_cleanup($component, $cachedhandlers) {
             $deletecount++;
         }
     }
+
+    // reset static handler cache
+    events_get_handlers('reset');
+
     return $deletecount;
 }
 
@@ -317,7 +321,27 @@ function events_dequeue($qhandler) {
     }
 }
 
+/**
+ * Returns hanflers for given event. Uses caching for better perf.
+ * @param string $eventanme name of even or 'reset'
+ * @return mixed array of handlers or false otherwise
+ *
+ * INTERNAL - to be used from eventslib only
+ */
+function events_get_handlers($eventname) {
+    static $handlers = array();
 
+    if ($eventname == 'reset') {
+        $handlers = array();
+        return false;
+    }
+
+    if (!array_key_exists($eventname, $handlers)) {
+        $handlers[$eventname] = get_records('events_handlers', 'eventname', $eventname);
+    }
+
+    return $handlers[$eventname];
+}
 
 /****** Public events API starts here, do not use functions above in 3rd party code ******/
 
@@ -378,7 +402,7 @@ function events_trigger($eventname, $eventdata) {
     $event = false;
 
     // pull out all registered event handlers
-    if ($handlers = get_records('events_handlers', 'eventname', $eventname)) {
+    if ($handlers = events_get_handlers($eventname)) {
         foreach ($handlers as $handler) {
 
            $errormessage = '';