<?php
  
  /**
   * ownCloud
   *
   * @author Jakob Sack
   * @copyright 2011 Jakob Sack kde@jakobsack.de
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
   * License as published by the Free Software Foundation; either
   * version 3 of the License, or any later version.
   *
   * This library 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 library.  If not, see <http://www.gnu.org/licenses/>.
   *
   */

  class OC_Connector_Sabre_Locks extends \Sabre\DAV\Locks\Backend\AbstractBackend {

  
  	/**

  	 * Returns a list of \Sabre\DAV\Locks_LockInfo objects

  	 *
  	 * This method should return all the locks for a particular uri, including
  	 * locks that might be set on a parent uri.
  	 *
  	 * If returnChildLocks is set to true, this method should also look for
  	 * any locks in the subtree of the uri for locks.
  	 *
  	 * @param string $uri
  	 * @param bool $returnChildLocks
  	 * @return array
  	 */
  	public function getLocks($uri, $returnChildLocks) {
  
  		// NOTE: the following 10 lines or so could be easily replaced by
  		// pure sql. MySQL's non-standard string concatination prevents us
  		// from doing this though.
  		// NOTE: SQLite requires time() to be inserted directly. That's ugly
  		// but otherwise reading locks from SQLite Databases will return
  		// nothing
  		$query = 'SELECT * FROM `*PREFIX*locks`'
  			   .' WHERE `userid` = ? AND (`created` + `timeout`) > '.time().' AND (( `uri` = ?)';
  		if (OC_Config::getValue( "dbtype") === 'oci') {
  			//FIXME oracle hack: need to explicitly cast CLOB to CHAR for comparison
  			$query = 'SELECT * FROM `*PREFIX*locks`'
  				   .' WHERE `userid` = ? AND (`created` + `timeout`) > '.time().' AND (( to_char(`uri`) = ?)';
  		}
  		$params = array(OC_User::getUser(), $uri);
  
  		// We need to check locks for every part in the uri.
  		$uriParts = explode('/', $uri);
  
  		// We already covered the last part of the uri
  		array_pop($uriParts);
  
  		$currentPath='';
  
  		foreach($uriParts as $part) {
  
  			if ($currentPath) $currentPath.='/';
  			$currentPath.=$part;
  			//FIXME oracle hack: need to explicitly cast CLOB to CHAR for comparison
  			if (OC_Config::getValue( "dbtype") === 'oci') {
  				$query.=' OR (`depth` != 0 AND to_char(`uri`) = ?)';
  			} else {
  				$query.=' OR (`depth` != 0 AND `uri` = ?)';
  			}
  			$params[] = $currentPath;
  
  		}
  
  		if ($returnChildLocks) {
  
  			//FIXME oracle hack: need to explicitly cast CLOB to CHAR for comparison
  			if (OC_Config::getValue( "dbtype") === 'oci') {
  				$query.=' OR (to_char(`uri`) LIKE ?)';
  			} else {
  				$query.=' OR (`uri` LIKE ?)';
  			}
  			$params[] = $uri . '/%';
  
  		}
  		$query.=')';

  		$result = OC_DB::executeAudited( $query, $params );
  		

  		$lockList = array();
  		while( $row = $result->fetchRow()) {

  			$lockInfo = new \Sabre\DAV\Locks\LockInfo();

  			$lockInfo->owner = $row['owner'];
  			$lockInfo->token = $row['token'];
  			$lockInfo->timeout = $row['timeout'];
  			$lockInfo->created = $row['created'];
  			$lockInfo->scope = $row['scope'];
  			$lockInfo->depth = $row['depth'];
  			$lockInfo->uri   = $row['uri'];
  			$lockList[] = $lockInfo;
  
  		}
  
  		return $lockList;
  
  	}
  
  	/**
  	 * Locks a uri
  	 *
  	 * @param string $uri

  	 * @param \Sabre\DAV\Locks\LockInfo $lockInfo

  	 * @return bool
  	 */

  	public function lock($uri, \Sabre\DAV\Locks\LockInfo $lockInfo) {

  
  		// We're making the lock timeout 5 minutes
  		$lockInfo->timeout = 300;
  		$lockInfo->created = time();
  		$lockInfo->uri = $uri;
  
  		$locks = $this->getLocks($uri, false);
  		$exists = false;
  		foreach($locks as $lock) {

  			if ($lock->token == $lockInfo->token) {
  				$exists = true;
  				break;
  			}

  		}
  
  		if ($exists) {

  			$sql = 'UPDATE `*PREFIX*locks`'
  				 .' SET `owner` = ?, `timeout` = ?, `scope` = ?, `depth` = ?, `uri` = ?, `created` = ?'
  				 .' WHERE `userid` = ? AND `token` = ?';
  			$result = OC_DB::executeAudited( $sql, array(

  				$lockInfo->owner,
  				$lockInfo->timeout,
  				$lockInfo->scope,
  				$lockInfo->depth,
  				$uri,
  				$lockInfo->created,
  				OC_User::getUser(),
  				$lockInfo->token)
  			);
  		} else {

  			$sql = 'INSERT INTO `*PREFIX*locks`'
  				 .' (`userid`,`owner`,`timeout`,`scope`,`depth`,`uri`,`created`,`token`)'
  				 .' VALUES (?,?,?,?,?,?,?,?)';
  			$result = OC_DB::executeAudited( $sql, array(

  				OC_User::getUser(),
  				$lockInfo->owner,
  				$lockInfo->timeout,
  				$lockInfo->scope,
  				$lockInfo->depth,
  				$uri,
  				$lockInfo->created,
  				$lockInfo->token)
  			);
  		}
  
  		return true;
  
  	}
  
  	/**
  	 * Removes a lock from a uri
  	 *
  	 * @param string $uri

  	 * @param \Sabre\DAV\Locks\LockInfo $lockInfo

  	 * @return bool
  	 */

  	public function unlock($uri, \Sabre\DAV\Locks\LockInfo $lockInfo) {

  		$sql = 'DELETE FROM `*PREFIX*locks` WHERE `userid` = ? AND `uri` = ? AND `token` = ?';
  		if (OC_Config::getValue( "dbtype") === 'oci') {
  			//FIXME oracle hack: need to explicitly cast CLOB to CHAR for comparison
  			$sql = 'DELETE FROM `*PREFIX*locks` WHERE `userid` = ? AND to_char(`uri`) = ? AND `token` = ?';
  		}
  		$result = OC_DB::executeAudited( $sql, array(OC_User::getUser(), $uri, $lockInfo->token));

  
  		return $result === 1;
  
  	}
  
  }