class.ilDAVLocks.php

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<?php
// BEGIN WebDAV
/*
    +-----------------------------------------------------------------------------+
    | ILIAS open source                                                           |
    +-----------------------------------------------------------------------------+
    | Copyright (c) 1998-2005 ILIAS open source, University of Cologne            |
    |                                                                             |
    | This program is free software; you can redistribute it and/or               |
    | modify it under the terms of the GNU General Public License                 |
    | as published by the Free Software Foundation; either version 2              |
    | 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 General Public License for more details.                                |
    |                                                                             |
    | You should have received a copy of the GNU General Public License           |
    | along with this program; if not, write to the Free Software                 |
    | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. |
    +-----------------------------------------------------------------------------+
*/

require_once "./Services/Object/classes/class.ilObject.php";
require_once "Services/WebDAV/classes/class.ilObjNull.php";
class ilDAVLocks
{
    private $table = 'dav_lock';

    private $isDebug = false;
    
    public function __construct()
    {
    }
    
    public function lockRef($refId, $iliasUserId, $davUser, $token, $expires, $depth, $scope)
    {
        $this->writelog('lockRef(' . $refId . ',' . $iliasUserId . ',' . $davUser . ',' . $token . ',' . $expires . ',' . $depth . ',' . $scope . ')');
        global $DIC;
        $tree = $DIC['tree'];
        $txt = $DIC['txt'];

        $result = true;
        $data = $tree->getNodeData($refId);

        // Check whether a lock on the path to the object prevents the creation
        // of a new lock
        $locksOnPath = $this->getLocksOnPathRef($refId);

        if ($scope == 'exclusive' && count($locksOnPath) > 0) {
            $result = 'couldnt create exclusive lock due to existing lock on path ' . var_export($locksOnPath, true);
        }

        foreach ($locksOnPath as $lock) {
            if ($lock['token'] == $token &&
                $lock['obj_id'] == $data['obj_id'] &&
                $lock['ilias_owner'] == $iliasUserId) {
                if ($this->updateLockWithoutCheckingObj($data['obj_id'], 0, $token, $expires)) {
                    return true;
                } else {
                    return 'couldnt update lock';
                }
            }
        }

        if ($result === true) {
            foreach ($locksOnPath as $lock) {
                if ($lock['scope'] == 'exclusive' &&
                    ($lock['depth'] == 'infinity' || $lock['obj_id'] == $data['obj_id']) &&
                    $lock['ilias_owner'] != $iliasUserId) {
                    $result = 'couldnt create lock due to exclusive lock on path ' . var_export($lock, true);
                    break;
                }
            }
        }

        // Check whether a lock on the children (subtree) of the object prevents
        // the creation of a new lock
        if ($result === true && $depth == 'infinity') {
            // XXX - if lock has depth infinity, we must check for locks in the subtree
        }

        if ($result === true) {
            $result = $this->lockWithoutCheckingObj(
                $data['obj_id'],
                0,
                $iliasUserId,
                $davUser,
                $token,
                $expires,
                $depth,
                $scope
            );
        }
        return $result;
    }

    public function lockWithoutCheckingDAV(&$objDAV, $iliasUserId, $davUser, $token, $expires, $depth, $scope)
    {
        $objId  = $objDAV->getObjectId();
        $nodeId = $objDAV->getNodeId();

        return $this->lockWithoutCheckingObj($objId, $nodeId, $iliasUserId, $davUser, $token, $expires, $depth, $scope);
    }
    public function lockWithoutCheckingObj($objId, $nodeId, $iliasUserId, $davUser, $token, $expires, $depth, $scope)
    {
        global $DIC;
        $ilDB = $DIC['ilDB'];
        
        switch ($depth) {
            case 'infinity': $depth = -1;
                break;
            case 0:
                $depth = 0;
                break;
            default:
                trigger_error('invalid depth ' . $depth, E_ERROR);
                return;
        }
        
        switch ($scope) {
            case 'exclusive': $scope = 'x'; break;
            case 'shared': $scope = 's'; break;
            default: trigger_error('invalid scope ' . $scope, E_ERROR); return;
        }
        
        $q = 'INSERT INTO ' . $this->table
                . ' SET obj_id   = ' . $ilDB->quote($objId, 'integer')
                . ', node_id     = ' . $ilDB->quote($nodeId, 'integer')
                . ', ilias_owner = ' . $ilDB->quote($iliasUserId, 'text')
                . ', dav_owner   = ' . $ilDB->quote($davUser, 'text')
                . ', token       = ' . $ilDB->quote($token, 'text')
                . ', expires     = ' . $ilDB->quote($expires, 'integer')
                . ', depth       = ' . $ilDB->quote($depth, 'integer')
                . ', type        = \'w\''
                . ', scope       = ' . $ilDB->quote($scope, 'text')
                ;
        $this->writelog('lock query=' . $q);
        $result = $ilDB->manipulate($q);
        return !PEAR::isError($result);
    }
    public function updateLockWithoutCheckingDAV(&$objDAV, $token, $expires)
    {
        global $DIC;
        $ilDB = $DIC['ilDB'];
        $objId  = $objDAV->getObjectId();
        $nodeId = $objDAV->getNodeId();

        return $this->updateLockWithoutCheckingObj($objId, $nodeId, $token, $expires);
    }
    public function updateLockWithoutCheckingObj($objId, $nodeId, $token, $expires)
    {
        global $DIC;
        $ilDB = $DIC['ilDB'];
        
        $q = 'UPDATE ' . $this->table
                . ' SET expires = ' . $ilDB->quote($expires, 'integer')
                . ' WHERE token = ' . $ilDB->quote($token, 'text')
                . ' AND obj_id = ' . $ilDB->quote($objId, 'integer')
                . ' AND node_id = ' . $ilDB->quote($nodeId, 'integer')
                ;
        $aff = $ilDB->manipulate($q);
        return $aff > 0;
    }
    public function unlockWithoutCheckingDAV(&$objDAV, $token)
    {
        global $DIC;
        $ilDB = $DIC['ilDB'];
        $this->writelog('unlock(' . $objDAV . ',' . $token . ')');
        
        $objId  = $objDAV->getObjectId();
        $nodeId = $objDAV->getNodeId();
        
        // Unlock object
        // FIXME - Maybe we should delete all rows with the same token, not
        // just the ones with the same token, obj_id and node_id.
        $q = 'DELETE FROM ' . $this->table
                . ' WHERE token = ' . $ilDB->quote($token, 'text')
                . ' AND obj_id = ' . $ilDB->quote($objId, 'integer')
                . ' AND node_id = ' . $ilDB->quote($nodeId, 'integer')
                ;
        $this->writelog('unlock query=' . $q);
        $aff = $ilDB->manipulate($q);
        $success = $aff > 0;
        
        // clean up expired locks in 1 out of 100 unlock requests
        $random = new \ilRandom();
        if ($random->int(1, 100) == 1) {
            $this->cleanUp();
        }
        
        return $success;
    }
    
    public function getLockDAV(&$objDAV, $token)
    {
        global $DIC;
        $ilDB = $DIC['ilDB'];
        $this->writelog('getLocks(' . $objDAV . ')');
        $objId  = $objDAV->getObjectId();
        $nodeId = $objDAV->getNodeId();
        
        $q = 'SELECT ilias_owner, dav_owner, expires, depth, scope'
                . ' FROM ' . $this->table
                . ' WHERE obj_id = ' . $ilDB->quote($objId, 'integer')
                . ' AND node_id = ' . $ilDB->quote($nodeId, 'integer')
                . ' AND token = ' . $ilDB->quote($token, 'text')
                ;
        $this->writelog('getLocks(' . $objDAV . ') query=' . $q);
        $r = $ilDB->query($q);
        
        $result = array();
        while ($row = $r->fetchRow(ilDBConstants::FETCHMODE_ASSOC)) {
            if ($row['depth'] == -1) {
                $row['depth'] = 'infinity';
            }
            $row['scope'] = ($row['scope'] == 'x') ? 'exclusive' : 'shared';
            $row['token'] = $token;
            $result = $row;
        }
        return $result;
    }
    public function getLocksOnObjectDAV(&$objDAV)
    {
        $objId  = $objDAV->getObjectId();
        $nodeId = $objDAV->getNodeId();

        return $this->getLocksOnObjectObj($objId, $nodeId);
    }
    public function getLocksOnObjectObj($objId, $nodeId = 0)
    {
        global $DIC;
        $ilDB = $DIC['ilDB'];
        $this->writelog('getLocks(' . $objDAV . ')');
        $nodeId = 0;
        $q = 'SELECT ilias_owner, dav_owner, token, expires, depth, scope'
                . ' FROM ' . $this->table
                . ' WHERE obj_id = ' . $ilDB->quote($objId, 'integer')
                . ' AND node_id = ' . $ilDB->quote($nodeId, 'integer')
                . ' AND expires > ' . $ilDB->quote(time(), 'integer')
                ;
        $this->writelog('getLocks(' . $objDAV . ') query=' . $q);
        $r = $ilDB->query($q);
        
        $result = array();
        while ($row = $r->fetchRow(ilDBConstants::FETCHMODE_ASSOC)) {
            if ($row['depth'] == -1) {
                $row['depth'] = 'infinity';
            }
            $row['scope'] = ($row['scope'] == 'x') ? 'exclusive' : 'shared';
            $result[] = $row;
        }
        return $result;
    }
    public function getLocksOnPathDAV(&$pathDAV)
    {
        global $DIC;
        $ilDB = $DIC['ilDB'];
        $this->writelog('getLocksOnPathDAV');
        
        $q = 'SELECT obj_id, node_id, ilias_owner, dav_owner, token, expires, depth, scope'
                    . ' FROM ' . $this->table
                    . ' WHERE expires > ' . $ilDB->quote(time(), 'integer')
                    . ' AND ('
                    ;
        $isFirst = true;
        foreach ($pathDAV as $objDAV) {
            $objId  = $objDAV->getObjectId();
            $nodeId = $objDAV->getNodeId();
            if ($isFirst) {
                $isFirst = false;
            } else {
                $q .= ' OR ';
            }
            $q .= '(obj_id = ' . $ilDB->quote($objId, 'integer') . ' AND node_id = ' . $ilDB->quote($nodeId, 'integer') . ')';
        }
        $q .= ')';
                
        $this->writelog('getLocksOnPathDAV(' . $objDAV . ') query=' . $q);
        $r = $ilDB->query($q);
        
        $result = array();
        while ($row = $r->fetchRow(ilDBConstants::FETCHMODE_ASSOC)) {
            if ($row['depth'] == -1) {
                $row['depth'] = 'infinity';
            }
            $row['scope'] = ($row['scope'] == 'x') ? 'exclusive' : 'shared';
            $result[] = $row;
        }
        $this->writelog('getLocksOnPathDAV:' . var_export($result, true));
        return $result;
    }
    public function getLocksOnPathRef($refId)
    {
        global $DIC;
        $ilDB = $DIC['ilDB'];
        $tree = $DIC['tree'];
        $this->writelog('getLocksOnPathRef(' . $refId . ')');

        $pathFull = $tree->getPathFull($refId);
        
        $q = 'SELECT obj_id, node_id, ilias_owner, dav_owner, token, expires, depth, scope'
                    . ' FROM ' . $this->table
                    . ' WHERE expires > ' . $ilDB->quote(time(), 'integer')
                    . ' AND ('
                    ;
        $isFirst = true;
        foreach ($pathFull as $pathItem) {
            $objId  = $pathItem['obj_id'];
            $nodeId = 0;
            if ($isFirst) {
                $isFirst = false;
            } else {
                $q .= ' OR ';
            }
            $q .= '(obj_id = ' . $ilDB->quote($objId, 'integer') . ' AND node_id = ' . $ilDB->quote($nodeId, 'integer') . ')';
        }
        $q .= ')';
                
        $this->writelog('getLocksOnPathRef(' . $refId . ') query=' . $q);
        $r = $ilDB->query($q);
        
        $result = array();
        while ($row = $r->fetchRow(ilDBConstants::FETCHMODE_ASSOC)) {
            if ($row['depth'] == -1) {
                $row['depth'] = 'infinity';
            }
            $row['scope'] = ($row['scope'] == 'x') ? 'exclusive' : 'shared';
            $result[] = $row;
        }
        return $result;
    }
    public function cleanUp()
    {
        global $DIC;
        $ilDB = $DIC['ilDB'];
        $tree = $DIC['tree'];

        // 1. Get rid of locks that have expired over an hour ago
        $old = time() - 3600;
        $q = 'DELETE'
            . ' FROM ' . $this->table
            . ' WHERE expires < ' . $ilDB->quote($old, 'integer')
        ;
        $ilDB->manipulate($q);
        
        // 2. Get rid of null resources which are not associated to
        //    a lock due to step 1, or due to a database inconsistency
        //    because we are working with non-transactional tables
        $q = 'SELECT dat.obj_id '
                . ' FROM object_data AS dat'
                . ' LEFT JOIN ' . $this->table . ' lck'
                . ' ON dat.obj_id = lck.obj_id'
                . ' WHERE dat.type = ' . $ilDB->quote('null', 'text')
                . ' AND lck.obj_id IS NULL'
                ;
        /*      TODO: smeyer.' FOR UPDATE' */
        
        $r = $ilDB->query($q);
        while ($row = $r->fetchRow(ilDBConstants::FETCHMODE_ASSOC)) {
            $references = ilObject::_getAllReferences($row['obj_id']);
            $obj = new ilObjNull($row['obj_id'], false);
            if (count($references) == 0) {
                $obj->delete();
            } else {
                foreach ($references as $refId) {
                    $obj->setRefId($refId);
                    $obj->delete();
                    $nodeData = $tree->getNodeData($refId);
                    $tree->deleteTree($nodeData);
                }
            }
        }
    }
    protected function writelog($message)
    {
        global $DIC;
        $log = $DIC['log'];
        $ilias = $DIC['ilias'];
        if ($this->isDebug) {
            $log->write(
                $ilias->account->getLogin()
                . ' DAV ilDAVLocks.' . str_replace("\n", ";", $message)
            );
        }
        /*
        if ($this->logFile)
        {
            $fh = fopen($this->logFile, 'a');
            fwrite($fh, date('Y-m-d h:i:s '));
            fwrite($fh, str_replace("\n",";",$message));
            fwrite($fh, "\n\n");
            fclose($fh);
        }*/
    }
}
// END WebDAV