/Zikula-1.2.3/system/PageLock/pnuserapi.php

<?php
/**
 * Zikula Application Framework
 * @copyright (c) Zikula Development Team
 * @link http://www.zikula.org
 * @version $Id: pnuserapi.php 27832 2009-12-09 11:50:03Z drak $
 * @license GNU/GPL - http://www.gnu.org/copyleft/gpl.html
 * @author Jorn Wildt
 * @package Zikula_System_Modules
 * @subpackage PageLock
 */

/**
 * length of time to lock a page
 *
 */
define('PageLockLifetime', 30);


function PageLock_userapi_pageLock($args)
{
    $lockName = $args['lockName'];
    $returnUrl = (array_key_exists('returnUrl', $args) ? $args['returnUrl'] : null);
    $ignoreEmptyLock = (array_key_exists('ignoreEmptyLock', $args) ? $args['ignoreEmptyLock'] : false);

    $uname = pnUserGetVar('uname');

    $lockedHtml = '';

    if (!empty($lockName) || !$ignoreEmptyLock) {
        PageUtil::AddVar('javascript', 'javascript/ajax/prototype.js');
        PageUtil::AddVar('javascript', 'javascript/ajax/scriptaculous.js');
        PageUtil::AddVar('javascript', 'javascript/ajax/pnajax.js');
        PageUtil::AddVar('javascript', 'system/PageLock/pnjavascript/pagelock.js');
        PageUtil::AddVar('stylesheet', ThemeUtil::getModuleStylesheet('PageLock'));

        $lockInfo = pnModAPIFunc('PageLock', 'user', 'requireLock',
                                 array('lockName'      => $lockName,
                                       'lockedByTitle' => $uname,
                                       'lockedByIPNo'  => $_SERVER['REMOTE_ADDR']));

        $hasLock = $lockInfo['hasLock'];

        if (!$hasLock) {
            $r = & pnRender::getInstance('PageLock');
            $r->assign('lockedBy', $lockInfo['lockedBy']);
            $lockedHtml = $r->fetch('PageLock_lockedwindow.html');
        }
    } else {
        $hasLock = true;
    }

    $html = "<script type=\"text/javascript\">\n";

    if (!empty($lockName))
    {
        if ($hasLock) {
            $html .= "Event.observe(window, 'load', PageLock.UnlockedPage);\n";
        } else {
            $html .= "Event.observe(window, 'load', PageLock.LockedPage);\n";
        }
    }

    $lockedHtml = str_replace("\n", "", $lockedHtml);
    $lockedHtml = str_replace("\r", "", $lockedHtml);

    // Use "PageLockLifetime*2/3" to add a good margin to lock timeout when pinging

    $returnUrl = DataUtil::formatForDisplayHTML($returnUrl);
    $html .= "
PageLock.LockName = '$lockName';
PageLock.BreakLockWarning = '" . __('Are you sure you want to break this lock?') . "';
PageLock.ReturnUrl = '$returnUrl';
PageLock.PingTime = " . (PageLockLifetime*2/3) . ";
PageLock.LockedHTML = '" . $lockedHtml . "';
</script>";

    PageUtil::addVar('rawtext', $html);

    return true;
}


function PageLock_userapi_requireLock(&$args)
{
    $lockName = $args['lockName'];
    $sessionId = (array_key_exists('sessionId', $args) ? $args['sessionId'] : session_id());
    $lockedByTitle = $args['lockedByTitle'];
    $lockedByIPNo = $args['lockedByIPNo'];

    PageLockRequireAccess();

    $locks = pnModAPIFunc('PageLock', 'user', 'getLocks',
                          $args);
    if (count($locks) > 0) {
        $lockedBy = '';
        foreach ($locks as $lock) {
            if (strlen($lockedBy) > 0) {
                $lockedBy .= ', ';
            }
            $lockedBy .= $lock['lockedByTitle'] . " ($lock[lockedByIPNo]) " . $lock['createdDate'];
        }

        return array('hasLock' => false, 'lockedBy' => $lockedBy);
    }

    $args['lockedBy'] = null;

    $pntable = pnDBGetTables();
    $pageLockTable = &$pntable['PageLock'];
    $pageLockColumn = &$pntable['PageLock_column'];

    // Look for existing lock

    $sql = "
SELECT COUNT(*)
FROM $pageLockTable
WHERE $pageLockColumn[name] = '" . DataUtil::formatForStore($lockName) . "' AND $pageLockColumn[lockedBySessionId] = '" . DataUtil::formatForStore($sessionId) . "'";

    $count = DBUtil::selectScalar($sql);

    $now = time();
    $expireDate = $now + PageLockLifetime;

    if ($count > 0) {
        // Update existing lock
        $sql = "
UPDATE $pageLockTable
SET $pageLockColumn[expiresDate] = '" . DateUtil::getDatetime($expireDate) . "'
WHERE $pageLockColumn[name] = '" . DataUtil::formatForStore($lockName) . "' AND $pageLockColumn[lockedBySessionId] = '" . DataUtil::formatForStore($sessionId) . "'";

        DBUtil::executeSql($sql);
    } else {
        $data = array('name' => $lockName,
                      'createdDate' => DateUtil::getDatetime($now),
                      'expiresDate' => DateUtil::getDatetime($expireDate),
                      'lockedBySessionId' => $sessionId,
                      'lockedByTitle' => $lockedByTitle,
                      'lockedByIPNo' => $lockedByIPNo);
        DBUtil::insertObject($data, 'PageLock');
    }

    PageLockReleaseAccess();

    return array('hasLock' => true);
}


function PageLock_userapi_getLocks($args)
{
    $lockName = $args['lockName'];
    $sessionId = (array_key_exists('sessionId', $args) ? $args['sessionId'] : session_id());

    PageLockRequireAccess();

    $dbconn = DBConnectionStack::getConnection();
    $pntable = pnDBGetTables();
    $pageLockTable = &$pntable['PageLock'];
    $pageLockColumn = &$pntable['PageLock_column'];

    $sql = "DELETE FROM $pageLockTable WHERE $pageLockColumn[expiresDate] < " . $dbconn->sysTimeStamp;
    DBUtil::executeSql($sql);

    $where = "$pageLockColumn[name] = '" . DataUtil::formatForStore($lockName) . "' AND $pageLockColumn[lockedBySessionId] != '" . DataUtil::formatForStore($sessionId) . "'";
    $locks = DBUtil::selectObjectArray('PageLock', $where);

    PageLockReleaseAccess();

    return $locks;
}


function PageLock_userapi_releaseLock($args)
{
    $lockName = $args['lockName'];
    $sessionId = (array_key_exists('sessionId', $args) ? $args['sessionId'] : session_id());

    PageLockRequireAccess();

    $pntable = pnDBGetTables();
    $pageLockTable = &$pntable['PageLock'];
    $pageLockColumn = &$pntable['PageLock_column'];

    $sql = "DELETE FROM $pageLockTable WHERE $pageLockColumn[name] = '" . DataUtil::formatForStore($lockName) . "' AND $pageLockColumn[lockedBySessionId] = '" . DataUtil::formatForStore($sessionId) . "'";
    DBUtil::executeSql($sql);

    PageLockReleaseAccess();

    return true;
}


// Internal locking mechanism to avoid concurrency inside the PageLock functions
function PageLockRequireAccess()
{
    global $PageLockAccessCount;
    if ($PageLockAccessCount == null) {
        $PageLockAccessCount = 0;
    }

    if ($PageLockAccessCount == 0) {
        global $PageLockFile;
        $ostemp = DataUtil::formatForOS(pnConfigGetVar('temp'), true);
        $PageLockFile = fopen($ostemp . '/pagelock.lock', "w+");
        flock($PageLockFile, LOCK_EX);
        fwrite($PageLockFile, "This is a locking file for synchronizing access to the PageLock module. Please do not delete.");
        fflush($PageLockFile);
    }

    ++$PageLockAccessCount;
}


// Internal locking mechanism to avoid concurrency inside the PageLock functions
function PageLockReleaseAccess()
{
    global $PageLockAccessCount;

    --$PageLockAccessCount;

    if ($PageLockAccessCount == 0) {
        global $PageLockFile;
        flock($PageLockFile, LOCK_UN);
        fclose($PageLockFile);
    }
}