forked from GNUsocial/gnu-social
44bcc942b8
Rearchitect (again!) notice stream code to delegate different functionality up and down the stack. Now, different classes implement NoticeStream.
130 lines
4.0 KiB
PHP
130 lines
4.0 KiB
PHP
<?php
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/**
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* StatusNet - the distributed open-source microblogging tool
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* Copyright (C) 2011, StatusNet, Inc.
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*
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* A stream of notices
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*
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* PHP version 5
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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* @category Stream
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* @package StatusNet
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* @author Evan Prodromou <evan@status.net>
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* @copyright 2011 StatusNet, Inc.
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* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
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* @link http://status.net/
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*/
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if (!defined('STATUSNET')) {
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// This check helps protect against security problems;
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// your code file can't be executed directly from the web.
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exit(1);
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}
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/**
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* Class for notice streams
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*
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* @category Stream
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* @package StatusNet
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* @author Evan Prodromou <evan@status.net>
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* @copyright 2011 StatusNet, Inc.
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* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
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* @link http://status.net/
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*/
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class CachingNoticeStream extends NoticeStream
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{
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const CACHE_WINDOW = 200;
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public $stream = null;
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public $cachekey = null;
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function __construct($stream, $cachekey)
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{
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$this->stream = $stream;
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$this->cachekey = $cachekey;
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}
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function getNoticeIds($offset=0, $limit=20, $sinceId=0, $maxId=0)
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{
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$cache = Cache::instance();
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// We cache self::CACHE_WINDOW elements at the tip of the stream.
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// If the cache won't be hit, just generate directly.
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if (empty($cache) ||
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$sinceId != 0 || $maxId != 0 ||
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is_null($limit) ||
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($offset + $limit) > self::CACHE_WINDOW) {
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return $this->stream->getNoticeIds($offset, $limit, $sinceId, $maxId);
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}
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// Check the cache to see if we have the stream.
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$idkey = Cache::key($this->cachekey);
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$idstr = $cache->get($idkey);
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if ($idstr !== false) {
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// Cache hit! Woohoo!
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$window = explode(',', $idstr);
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$ids = array_slice($window, $offset, $limit);
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return $ids;
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}
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// Check the cache to see if we have a "last-known-good" version.
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// The actual cache gets blown away when new notices are added, but
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// the "last" value holds a lot of info. We might need to only generate
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// a few at the "tip", which can bound our queries and save lots
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// of time.
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$laststr = $cache->get($idkey.';last');
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if ($laststr !== false) {
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$window = explode(',', $laststr);
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$last_id = $window[0];
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$new_ids = $this->stream->getNoticeIds(0, self::CACHE_WINDOW, $last_id, 0);
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$new_window = array_merge($new_ids, $window);
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$new_windowstr = implode(',', $new_window);
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$result = $cache->set($idkey, $new_windowstr);
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$result = $cache->set($idkey . ';last', $new_windowstr);
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$ids = array_slice($new_window, $offset, $limit);
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return $ids;
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}
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// No cache hits :( Generate directly and stick the results
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// into the cache. Note we generate the full cache window.
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$window = $this->stream->getNoticeIds(0, self::CACHE_WINDOW, 0, 0);
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$windowstr = implode(',', $window);
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$result = $cache->set($idkey, $windowstr);
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$result = $cache->set($idkey . ';last', $windowstr);
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// Return just the slice that was requested
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$ids = array_slice($window, $offset, $limit);
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return $ids;
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}
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}
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