gnu-social/lib/filteringnoticestream.php

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<?php
/**
* StatusNet - the distributed open-source microblogging tool
* Copyright (C) 2011, StatusNet, Inc.
*
* A notice stream that filters its upstream content
*
* PHP version 5
*
* 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 Stream
* @package StatusNet
* @author Evan Prodromou <evan@status.net>
* @copyright 2011 StatusNet, Inc.
* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
* @link http://status.net/
*/
if (!defined('STATUSNET')) {
// This check helps protect against security problems;
// your code file can't be executed directly from the web.
exit(1);
}
/**
* A class for presenting a filtered notice stream based on an upstream stream
*
* @category Stream
* @package StatusNet
* @author Evan Prodromou <evan@status.net>
* @copyright 2011 StatusNet, Inc.
* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
* @link http://status.net/
*/
abstract class FilteringNoticeStream extends NoticeStream
{
protected $upstream;
function __construct($upstream)
{
$this->upstream = $upstream;
}
abstract function filter($notice);
function getNoticeIds($offset, $limit, $since_id, $max_id)
{
// "offset" is virtual; we have to get a lot
$total = $offset + $limit;
$filtered = array();
$startAt = 0;
$askFor = $total;
// Keep going till we have $total notices in $notices array,
// or we get nothing from upstream.
$results = null;
$round = 0;
do {
$raw = $this->upstream->getNotices($startAt, $askFor, $since_id, $max_id);
$results = $raw->N;
if ($results == 0) {
break;
}
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$notices = $raw->fetchAll();
$this->prefill($notices);
foreach ($notices as $notice) {
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if ($this->filter($notice)) {
$filtered[] = $notice->id;
if (count($filtered) >= $total) {
break;
}
}
}
// XXX: make these smarter; factor hit rate into $askFor
$startAt += $askFor;
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$hits = count($filtered);
$lastAsk = $askFor;
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if ($hits === 0) {
$askFor = max(min(2 * $askFor, NOTICES_PER_PAGE * 50), NOTICES_PER_PAGE);
} else {
$askFor = max(min(intval(ceil(($total - $hits)*$startAt/$hits)), NOTICES_PER_PAGE * 50), NOTICES_PER_PAGE);
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}
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$round++;
} while (count($filtered) < $total && $results >= $lastAsk);
return array_slice(array_values($filtered), $offset, $limit);
}
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function prefill($notices)
{
return;
}
}