XMPP queued output & initial retooling of DB queue manager to support non-Notice objects.

Queue handlers for XMPP individual & firehose output now send their XML stanzas
to another output queue instead of connecting directly to the chat server. This
lets us have as many general processing threads as we need, while all actual
XMPP input and output go through a single daemon with a single connection open.

This avoids problems with multiple connected resources:
* multiple windows shown in some chat clients (psi, gajim, kopete)
* extra load on server
* incoming message delivery forwarding issues

Database changes:
* queue_item drops 'notice_id' in favor of a 'frame' blob.
  This is based on Craig Andrews' work branch to generalize queues to take any
  object, but conservatively leaving out the serialization for now.
  Table updater (preserves any existing queued items) in db/rc3to09.sql

Code changes to watch out for:
* Queue handlers should now define a handle() method instead of handle_notice()
* QueueDaemon and XmppDaemon now share common i/o (IoMaster) and respawning
  thread management (RespawningDaemon) infrastructure.
* The polling XmppConfirmManager has been dropped, as the message is queued
  directly when saving IM settings.
* Enable $config['queue']['debug_memory'] to output current memory usage at
  each run through the event loop to watch for memory leaks

To do:
* Adapt XMPP i/o to component connection mode for multi-site support.
* XMPP input can also be broken out to a queue, which would allow the actual
  notice save etc to be handled by general queue threads.
* Make sure there are no problems with simply pushing serialized Notice objects
  to queues.
* Find a way to improve interactive performance of the database-backed queue
  handler; polling is pretty painful to XMPP.
* Possibly redo the way QueueHandlers are injected into a QueueManager. The
  grouping used to split out the XMPP output queue is a bit awkward.

1 files changed, 16 insertions, 14 deletions

diff --git a/classes/Queue_item.php b/classes/Queue_item.php
index cf805a606..f83c2cef1 100644
--- a/classes/Queue_item.php
+++ b/classes/Queue_item.php
@@ -10,8 +10,8 @@ class Queue_item extends Memcached_DataObject
     /* the code below is auto generated do not remove the above tag */
 
     public $__table = 'queue_item';                      // table name
-    public $notice_id;                       // int(4)  primary_key not_null
-    public $transport;                       // varchar(8)  primary_key not_null
+    public $id;                              // int(4)  primary_key not_null
+    public $frame;                           // blob not_null
     public $created;                         // datetime()   not_null
     public $claimed;                         // datetime()
 
@@ -22,14 +22,21 @@ class Queue_item extends Memcached_DataObject
     /* the code above is auto generated do not remove the tag below */
     ###END_AUTOCODE
 
-    function sequenceKey()
-    { return array(false, false); }
-
-    static function top($transport=null) {
+    /**
+     * @param mixed $transports name of a single queue or array of queues to pull from
+     *                          If not specified, checks all queues in the system.
+     */
+    static function top($transports=null) {
 
         $qi = new Queue_item();
-        if ($transport) {
-            $qi->transport = $transport;
+        if ($transports) {
+            if (is_array($transports)) {
+                // @fixme use safer escaping
+                $list = implode("','", array_map('addslashes', $transports));
+                $qi->whereAdd("transport in ('$list')");
+            } else {
+                $qi->transport = $transports;
+            }
         }
         $qi->orderBy('created');
         $qi->whereAdd('claimed is null');
@@ -42,7 +49,7 @@ class Queue_item extends Memcached_DataObject
             # XXX: potential race condition
             # can we force it to only update if claimed is still null
             # (or old)?
-            common_log(LOG_INFO, 'claiming queue item = ' . $qi->notice_id .
+            common_log(LOG_INFO, 'claiming queue item id = ' . $qi->id .
                 ' for transport ' . $qi->transport);
             $orig = clone($qi);
             $qi->claimed = common_sql_now();
@@ -57,9 +64,4 @@ class Queue_item extends Memcached_DataObject
         $qi = null;
         return null;
     }
-
-    function pkeyGet($kv)
-    {
-        return Memcached_DataObject::pkeyGet('Queue_item', $kv);
-    }
 }