forked from GNUsocial/gnu-social
		
	There were some differences between defaults for the NoticeStream::getNoticeIds() function and some of its subclasses' implementations. So, I got them rationalized.
		
			
				
	
	
		
			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, $limit, $sinceId, $maxId)
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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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