Merge branch 'queuemanager' into 0.8.x

1 files changed, 166 insertions, 0 deletions

diff --git a/lib/dbqueuemanager.php b/lib/dbqueuemanager.php
new file mode 100644
index 000000000..6e7172de0
--- /dev/null
+++ b/lib/dbqueuemanager.php
@@ -0,0 +1,166 @@
+<?php
+/**
+ * Laconica, the distributed open-source microblogging tool
+ *
+ * Simple-minded queue manager for storing items in the database
+ *
+ * PHP version 5
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  QueueManager
+ * @package   Laconica
+ * @author    Evan Prodromou <evan@controlyourself.ca>
+ * @author    Sarven Capadisli <csarven@controlyourself.ca>
+ * @copyright 2009 Control Yourself, Inc.
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://laconi.ca/
+ */
+
+class DBQueueManager extends QueueManager
+{
+    var $qis = array();
+
+    function enqueue($object, $queue)
+    {
+        $notice = $object;
+
+        $qi = new Queue_item();
+
+        $qi->notice_id = $notice->id;
+        $qi->transport = $queue;
+        $qi->created   = $notice->created;
+        $result        = $qi->insert();
+
+        if (!$result) {
+            common_log_db_error($qi, 'INSERT', __FILE__);
+            throw new ServerException('DB error inserting queue item');
+        }
+
+        return true;
+    }
+
+    function service($queue, $handler)
+    {
+        while (true) {
+            $this->_log(LOG_DEBUG, 'Checking for notices...');
+            $notice = $this->_nextItem($queue, null);
+            if (empty($notice)) {
+                $this->_log(LOG_DEBUG, 'No notices waiting; idling.');
+                // Nothing in the queue. Do you
+                // have other tasks, like servicing your
+                // XMPP connection, to do?
+                $handler->idle(QUEUE_HANDLER_MISS_IDLE);
+            } else {
+                $this->_log(LOG_INFO, 'Got notice '. $notice->id);
+                // Yay! Got one!
+                if ($handler->handle_notice($notice)) {
+                    $this->_log(LOG_INFO, 'Successfully handled notice '. $notice->id);
+                    $this->_done($notice, $queue);
+                } else {
+                    $this->_log(LOG_INFO, 'Failed to handle notice '. $notice->id);
+                    $this->_fail($notice, $queue);
+                }
+                // Chance to e.g. service your XMPP connection
+                $this->_log(LOG_DEBUG, 'Idling after success.');
+                $handler->idle(QUEUE_HANDLER_HIT_IDLE);
+            }
+            // XXX: when do we give up?
+        }
+    }
+
+    function _nextItem($queue, $timeout=null)
+    {
+        $start = time();
+        $result = null;
+
+        do {
+            $qi = Queue_item::top($queue);
+            if (!empty($qi)) {
+                $notice = Notice::staticGet('id', $qi->notice_id);
+                if (!empty($notice)) {
+                    $result = $notice;
+                } else {
+                    $this->_log(LOG_INFO, 'dequeued non-existent notice ' . $notice->id);
+                    $qi->delete();
+                    $qi->free();
+                    $qi = null;
+                }
+            }
+        } while (empty($result) && (is_null($timeout) || (time() - $start) < $timeout));
+
+        return $result;
+    }
+
+    function _done($object, $queue)
+    {
+        // XXX: right now, we only handle notices
+
+        $notice = $object;
+
+        $qi = Queue_item::pkeyGet(array('notice_id' => $notice->id,
+                                        'transport' => $queue));
+
+        if (empty($qi)) {
+            $this->_log(LOG_INFO, 'Cannot find queue item for notice '.$notice->id.', queue '.$queue);
+        } else {
+            if (empty($qi->claimed)) {
+                $this->_log(LOG_WARNING, 'Reluctantly releasing unclaimed queue item '.
+                           'for '.$notice->id.', queue '.$queue);
+            }
+            $qi->delete();
+            $qi->free();
+            $qi = null;
+        }
+
+        $this->_log(LOG_INFO, 'done with notice ID = ' . $notice->id);
+
+        $notice->free();
+        $notice = null;
+    }
+
+    function _fail($object, $queue)
+    {
+        // XXX: right now, we only handle notices
+
+        $notice = $object;
+
+        $qi = Queue_item::pkeyGet(array('notice_id' => $notice->id,
+                                        'transport' => $queue));
+
+        if (empty($qi)) {
+            $this->_log(LOG_INFO, 'Cannot find queue item for notice '.$notice->id.', queue '.$queue);
+        } else {
+            if (empty($qi->claimed)) {
+                $this->_log(LOG_WARNING, 'Ignoring failure for unclaimed queue item '.
+                           'for '.$notice->id.', queue '.$queue);
+            } else {
+                $orig = clone($qi);
+                $qi->claimed = null;
+                $qi->update($orig);
+                $qi = null;
+            }
+        }
+
+        $this->_log(LOG_INFO, 'done with notice ID = ' . $notice->id);
+
+        $notice->free();
+        $notice = null;
+    }
+
+    function _log($level, $msg)
+    {
+        common_log($level, 'DBQueueManager: '.$msg);
+    }
+}