Cache/src/storage/apc/apc_array.php - zetacomponents - Git at Google

 <?php
 /**
  * File containing the ezcCacheStorageFileApcArray class.
  *
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
  * with the License.  You may obtain a copy of the License at
  *
  *   http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing,
  * software distributed under the License is distributed on an
  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  * KIND, either express or implied.  See the License for the
  * specific language governing permissions and limitations
  * under the License.
  *
  * @package Cache
  * @version //autogentag//
  * @license http://www.apache.org/licenses/LICENSE-2.0 Apache License, Version 2.0
  * @filesource
  */

 /**
  * This class is a replacement for the {@link ezcCacheStorageFileArray} class. Tries
  * to serve data from a local APC cache if possible.
  *
  * Options for this class are defined in {@link ezcCacheStorageFileApcArrayOptions}.
  *
  * @apichange This class might be removed in future versions. Please use
  *            {@link ezcCacheStack} to achieve the desired behaior.
  * @package Cache
  * @version //autogentag//
  */
 class ezcCacheStorageFileApcArray extends ezcCacheStorageApc
 {
     /**
      * Creates a new cache storage in the given location. The location in case
      * of this storage class must a valid file system directory.
      *
      * Options can contain the 'ttl' (Time-To-Live). This is per default set
      * to 1 day. The option 'permissions' can be used to define the file
      * permissions of created cache items.
      *
      * For details about the options see {@link ezcCacheStorageFileApcArrayOptions}.
      *
      * @throws ezcBasePropertyNotFoundException
      *         If you tried to set a non-existent option value.
      *
      * @param string $location Path to the cache location. Must be a valid path
      * @param array(string=>string) $options Options for the cache storage
      */
     public function __construct( $location, array $options = array() )
     {
         parent::__construct( $location, array() );

         // Overwrite parent set options with new ezcCacheStorageFileApcArrayOptions
         $this->properties['options'] = new ezcCacheStorageFileApcArrayOptions( $options );
     }

     /**
      * Fetches the data from the cache.
      *
      * @param string $filename The ID/filename from where to fetch the object
      * @param bool $useApc Use APC or the file system
      * @return mixed The fetched data or false on failure
      */
     protected function fetchData( $filename, $useApc = false )
     {
         if ( $useApc === true )
         {
             $data = $this->backend->fetch( $filename );
             return ( is_object( $data ) ) ? $data->data : false;
         }
         else
         {
             return ( include $filename );
         }
     }

     /**
      * Fetches the object from the cache.
      *
      * @param string $filename The ID/filename from where to fetch the data
      * @return mixed The fetched object or false on failure
      */
     protected function fetchObject( $filename )
     {
         $data = $this->backend->fetch( $filename );
         return ( is_object( $data ) ) ? $data : false;
     }

     /**
      * Wraps the data in order to be stored in APC ($useApc = true) or on the
      * file system ($useApc = false).
      *
      * @throws ezcCacheInvalidDataException
      *         If the data submitted can not be handled by this storage (object,
      *         resource).
      *
      * @param mixed $data Simple type or array
      * @param bool $useApc Use APC or not
      * @return mixed Prepared data
      */
     protected function prepareData( $data, $useApc = false )
     {
         if ( $useApc === true )
         {
             if ( is_resource( $data ) )
             {
                 throw new ezcCacheInvalidDataException( gettype( $data ), array( 'simple', 'array', 'object' ) );
             }
             return new ezcCacheStorageFileApcArrayDataStruct( $data, $this->properties['location'] );
         }
         else
         {
             if ( is_object( $data )
                  || is_resource( $data ) )
             {
                 throw new ezcCacheInvalidDataException( gettype( $data ), array( 'simple', 'array' ) );
             }
             return "<?php\nreturn " . var_export( $data, true ) . ";\n?>\n";
         }
     }

     /**
      * Stores data to the cache storage.
      *
      * @throws ezcBaseFilePermissionException
      *         If the directory to store the cache file could not be created.
      *         This exception means most likely that your cache directory
      *         has been corrupted by external influences (file permission
      *         change).
      * @throws ezcBaseFileIoException
      *         If an error occured while writing the data to the cache. If this
      *         exception occurs, a serious error occured and your storage might
      *         be corruped (e.g. broken network connection, file system broken,
      *         ...).
      * @throws ezcCacheInvalidDataException
      *         If the data submitted can not be handled by the implementation
      *         of {@link ezcCacheStorageFile}. Most implementations can not
      *         handle objects and resources.
      * @throws ezcCacheApcException
      *         If the data could not be stored in APC.
      *
      * @param string $id Unique identifier
      * @param mixed $data The data to store
      * @param array(string=>string) $attributes Attributes describing the cached data
      * @return string The ID string of the newly cached data
      */
     public function store( $id, $data, $attributes = array() )
     {
         // Generates the identifier
         $filename = $this->properties['location'] . $this->generateIdentifier( $id, $attributes );

         // Purges the Registry Cache
         if ( isset( $this->registry[$filename] ) )
         {
             unset( $this->registry[$filename] );
         }

         // Deletes the files if it already exists on the filesystem
         if ( file_exists( $filename ) )
         {
             if ( unlink( $filename ) === false )
             {
                 throw new ezcBaseFilePermissionException( $filename, ezcBaseFileException::WRITE, 'Could not delete existing cache file.' );
             }
         }

         // Deletes the data from APC if it already exists
         $this->backend->delete( $filename );

         // Prepares the data for filesystem storage
         $dataStr = $this->prepareData( $data );

         // Tries to create the directory on the filesystem
         $dirname = dirname( $filename );
         if ( !is_dir( $dirname )
              && !mkdir( $dirname, 0777, true ) )
         {
             throw new ezcBaseFilePermissionException( $dirname, ezcBaseFileException::WRITE, 'Could not create directory to store cache file.' );
         }

         // Tries to write the file the filesystem
         if ( @file_put_contents( $filename, $dataStr ) !== strlen( $dataStr ) )
         {
             throw new ezcBaseFileIoException( $filename, ezcBaseFileException::WRITE, 'Could not write data to cache file.' );
         }

         // Tries to set the file permissions
         if ( ezcBaseFeatures::os() !== "Windows" )
         {
             chmod( $filename, $this->options->permissions );
         }

         // Prepares the data for APC storage
         $dataObj = $this->prepareData( $data, true );
         $dataObj->mtime = @filemtime( $filename );
         $dataObj->atime = time();

         // Stores it in APC
         $this->registerIdentifier( $id, $attributes, $filename );
         if ( !$this->backend->store( $filename, $dataObj, $this->properties['options']['ttl'] ) )
         {
             throw new ezcCacheApcException( "APC store failed." );
         }

         // Returns the ID for no good reason
         return $id;
     }

     /**
      * Restores the data from the cache.
      *
      * @param string $id The item ID to restore
      * @param array(string=>string) $attributes Attributes describing the data to restore
      * @param bool $search Whether to search for items if not found directly
      * @return mixed The cached data on success, otherwise false
      */
     public function restore( $id, $attributes = array(), $search = false )
     {
         // Generates the identifier
         $filename = $this->properties['location'] . $this->generateIdentifier( $id, $attributes );

         // Grabs the data object from the APC
         $dataObj = $this->fetchObject( $filename );
         $useApc = false;

         // Checks the APC object exists
         if ( $dataObj !== false
              && is_object( $dataObj )
              && isset( $dataObj->atime ) )
         {
             $useApc = true;
         }

         // Checks the APC object is still valid
         if ( !isset( $this->registry[$filename] )
              && $useApc === true
              && time() === $dataObj->atime )
         {
             // Make sure the FileSystem still has the file and that it hasn't changed
             if ( file_exists( $filename ) !== false
                  && @filemtime( $filename ) === $dataObj->mtime )
             {
                 $dataObj->atime = time();
                 $this->backend->store( $filename, $dataObj, $this->properties['options']['ttl'] );
             }
             else
             {
                 $useApc = false;
                 $this->backend->delete( $filename );
             }
         }

         // Searches the filesystem for the file
         if ( !isset( $this->registry[$filename] )
              && $useApc === false
              && file_exists( $filename ) === false )
         {
             if ( $search === true
                  && count( $files = $this->search( $id, $attributes ) ) === 1 )
             {
                 $filename = $files[0][2];
             }
             else
             {
                 // There are more elements found during search, so false is returned
                 return false;
             }
         }

         // Returns false if no data is stored anywhere
         if ( $useApc === false
              && file_exists( $filename ) === false )
         {
             // Purges APC
             $this->backend->delete( $filename );

             // Purges Registry Cache
             if ( isset( $this->registry[$filename] ) )
             {
                 unset( $this->registry[$filename] );
             }

             return false;
         }

         // Creates a Registry Object -- should only happen once per page load
         if ( !isset( $this->registry[$filename] ) )
         {
             $this->registry[$filename] = new stdClass();
             $this->registry[$filename]->data = false;
             $this->registry[$filename]->mtime = $useApc ? $dataObj->mtime : null;
             $this->registry[$filename]->lifetime = $this->calcLifetime( $filename, $useApc );
         }

         // Purges the data if it is expired
         if ( $this->properties['options']['ttl'] !== false
              && $this->calcLifetime( $filename, $useApc ) > $this->properties['options']['ttl'] )
         {
             $this->delete( $id, $attributes, false ); // don't search
             return false;
         }

         // Returns the data from the Registry Cache
         if ( $this->registry[$filename]->data !== false )
         {
             return ( $this->registry[$filename]->data );
         }

         // Returns data from APC
         else if ( $useApc === true
                   && ( isset( $dataObj->data ) || is_null( $dataObj->data ) ) )
         {
             $this->registry[$filename]->data = $dataObj->data; // primes the Registry cache
             return ( $dataObj->data );
         }

         // Returns data from the filesystem
         else if ( file_exists( $filename ) !== false )
         {
             // Grabs the data from the filesystem
             $dataStr = $this->fetchData( $filename );

             // Stores it in the Registry Cache
             $this->registry[$filename]->data = $dataStr;

             // Prepares the data for APC storage
             $dataObj = $this->prepareData( $dataStr, true );
             $dataObj->mtime = @filemtime( $filename );
             $dataObj->atime = time();

             // Stores it in APC
             $this->backend->store( $filename, $dataObj, $this->properties['options']['ttl'] );

             // Returns the data
             return ( $dataStr );
         }
         else
         {
             return false;
         }
     }

     /**
      * Deletes the data associated with $id or $attributes from the cache.
      *
      * @throws ezcBaseFilePermissionException
      *         If an already existsing cache file could not be unlinked.
      *         This exception means most likely that your cache directory
      *         has been corrupted by external influences (file permission
      *         change).
      *
      * @param string $id The item ID to purge
      * @param array(string=>string) $attributes Attributes describing the data to restore
      * @param bool $search Whether to search for items if not found directly
      */
     public function delete( $id = null, $attributes = array(), $search = false )
     {
         $location = $this->properties['location'];
         // Generates the identifier
         $filename = $location . $this->generateIdentifier( $id, $attributes );

         // Initializes the array
         $delFiles = array();

         clearstatcache();

         // Checks if the file exists on the filesystem
         if ( file_exists( $filename ) )
         {
             $delFiles[] = array( $id, $attributes, $filename );
         }
         else if ( $search === true )
         {
             $delFiles = $this->search( $id, $attributes );
         }

         $deletedIds = array();
         // Deletes the files
         foreach ( $delFiles as $count => $filename )
         {
             // Deletes from Registry Cache
             if ( isset( $this->registry[$filename[2]] ) )
             {
                 unset( $this->registry[$filename[2]] );
             }

             // Deletes from APC
             $this->backend->delete( $filename[2] );
             $this->unRegisterIdentifier( $filename[0], $filename[1], $filename[2], true );
             if ( isset( $this->registry[$location][$filename[0]][$filename[2]] ) )
             {
                 unset( $this->registry[$location][$filename[0]][$filename[2]] );
             }

             // Deletes from the filesystem
             if ( @unlink( $filename[2] ) === false )
             {
                 throw new ezcBaseFilePermissionException(
                     $filename,
                     ezcBaseFileException::WRITE,
                     'Could not unlink cache file.'
                 );
             }
             $deletedIds[] = $filename[0];
         }
         $this->storeSearchRegistry();
         return $deletedIds;
     }

     /**
      * Checks the path in the location property exists, and is read-/writable. It
      * throws an exception if not.
      *
      * @throws ezcBaseFileNotFoundException
      *         If the storage location does not exist. This should usually not
      *         happen, since {@link ezcCacheManager::createCache()} already
      *         performs sanity checks for the cache location. In case this
      *         exception is thrown, your cache location has been corrupted
      *         after the cache was configured.
      * @throws ezcBaseFileNotFoundException
      *         If the storage location is not a directory. This should usually
      *         not happen, since {@link ezcCacheManager::createCache()} already
      *         performs sanity checks for the cache location. In case this
      *         exception is thrown, your cache location has been corrupted
      *         after the cache was configured.
      * @throws ezcBaseFilePermissionException
      *         If the storage location is not writeable. This should usually not
      *         happen, since {@link ezcCacheManager::createCache()} already
      *         performs sanity checks for the cache location. In case this
      *         exception is thrown, your cache location has been corrupted
      *         after the cache was configured.
      */
     protected function validateLocation()
     {
         if ( file_exists( $this->properties['location'] ) === false )
         {
             throw new ezcBaseFileNotFoundException( $this->properties['location'], 'cache location' );
         }

         if ( is_dir( $this->properties['location'] ) === false )
         {
             throw new ezcBaseFileNotFoundException( $this->properties['location'], 'cache location', 'Cache location not a directory.' );
         }

         if ( is_writeable( $this->properties['location'] ) === false )
         {
             throw new ezcBaseFilePermissionException( $this->properties['location'], ezcBaseFileException::WRITE, 'Cache location is not a directory.' );
         }
     }

     /**
      * Calculates the lifetime remaining for a cache object.
      *
      * If the TTL option is set to false, this method will always return 1 for
      * existing items.
      *
      * @param string $filename The file to calculate the remaining lifetime for
      * @param bool $useApc Use APC or not
      * @return int The remaining lifetime in seconds (0 if no time remaining)
      */
     protected function calcLifetime( $filename, $useApc = false )
     {
         $ttl = $this->options->ttl;
         // Calculate when the APC object was created
         if ( $useApc === true )
         {
             // we've likely already looked this thing up in APC, so we'll grab the local object
             if ( isset( $this->registry[$filename] ) )
             {
                 $dataObj = $this->registry[$filename];
             }
             else // otherwise we'll grab it from APC
             {
                 $dataObj = $this->fetchObject( $filename );
             }

             if ( is_object( $dataObj ) )
             {
                 if ( $ttl === false )
                 {
                     return 1;
                 }
                 return (
                     ( $lifeTime = ( time() - $dataObj->mtime ) ) > $ttl
                     ? $ttl - $lifeTime
                     : 0
                 );
             }
             else
             {
                 return 0;
             }
         }

         // Calculate when the filesystem file was created
         else
         {
             if ( ( file_exists( $filename ) !== false )
                  && ( ( $modTime = @filemtime( $filename ) ) !== false ) )
             {
                 if ( $ttl === false )
                 {
                     return 1;
                 }
                 return (
                     ( $lifeTime = ( time() - $modTime ) ) < $ttl
                     ? $ttl - $lifeTime
                     : 0
                 );
             }
             else
             {
                 return 0;
             }
         }
     }
 }
 ?>
	<?php
	/**
	* File containing the ezcCacheStorageFileApcArray class.
	*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you under the Apache License, Version 2.0 (the
	* "License"); you may not use this file except in compliance
	* with the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing,
	* software distributed under the License is distributed on an
	* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
	* KIND, either express or implied. See the License for the
	* specific language governing permissions and limitations
	* under the License.
	*
	* @package Cache
	* @version //autogentag//
	* @license http://www.apache.org/licenses/LICENSE-2.0 Apache License, Version 2.0
	* @filesource
	*/

	/**
	* This class is a replacement for the {@link ezcCacheStorageFileArray} class. Tries
	* to serve data from a local APC cache if possible.
	*
	* Options for this class are defined in {@link ezcCacheStorageFileApcArrayOptions}.
	*
	* @apichange This class might be removed in future versions. Please use
	* {@link ezcCacheStack} to achieve the desired behaior.
	* @package Cache
	* @version //autogentag//
	*/
	class ezcCacheStorageFileApcArray extends ezcCacheStorageApc
	{
	/**
	* Creates a new cache storage in the given location. The location in case
	* of this storage class must a valid file system directory.
	*
	* Options can contain the 'ttl' (Time-To-Live). This is per default set
	* to 1 day. The option 'permissions' can be used to define the file
	* permissions of created cache items.
	*
	* For details about the options see {@link ezcCacheStorageFileApcArrayOptions}.
	*
	* @throws ezcBasePropertyNotFoundException
	* If you tried to set a non-existent option value.
	*
	* @param string $location Path to the cache location. Must be a valid path
	* @param array(string=>string) $options Options for the cache storage
	*/
	public function __construct( $location, array $options = array() )
	{
	parent::__construct( $location, array() );

	// Overwrite parent set options with new ezcCacheStorageFileApcArrayOptions
	$this->properties['options'] = new ezcCacheStorageFileApcArrayOptions( $options );
	}

	/**
	* Fetches the data from the cache.
	*
	* @param string $filename The ID/filename from where to fetch the object
	* @param bool $useApc Use APC or the file system
	* @return mixed The fetched data or false on failure
	*/
	protected function fetchData( $filename, $useApc = false )
	{
	if ( $useApc === true )
	{
	$data = $this->backend->fetch( $filename );
	return ( is_object( $data ) ) ? $data->data : false;
	}
	else
	{
	return ( include $filename );
	}
	}

	/**
	* Fetches the object from the cache.
	*
	* @param string $filename The ID/filename from where to fetch the data
	* @return mixed The fetched object or false on failure
	*/
	protected function fetchObject( $filename )
	{
	$data = $this->backend->fetch( $filename );
	return ( is_object( $data ) ) ? $data : false;
	}

	/**
	* Wraps the data in order to be stored in APC ($useApc = true) or on the
	* file system ($useApc = false).
	*
	* @throws ezcCacheInvalidDataException
	* If the data submitted can not be handled by this storage (object,
	* resource).
	*
	* @param mixed $data Simple type or array
	* @param bool $useApc Use APC or not
	* @return mixed Prepared data
	*/
	protected function prepareData( $data, $useApc = false )
	{
	if ( $useApc === true )
	{
	if ( is_resource( $data ) )
	{
	throw new ezcCacheInvalidDataException( gettype( $data ), array( 'simple', 'array', 'object' ) );
	}
	return new ezcCacheStorageFileApcArrayDataStruct( $data, $this->properties['location'] );
	}
	else
	{
	if ( is_object( $data )
	\|\| is_resource( $data ) )
	{
	throw new ezcCacheInvalidDataException( gettype( $data ), array( 'simple', 'array' ) );
	}
	return "<?php\nreturn " . var_export( $data, true ) . ";\n?>\n";
	}
	}

	/**
	* Stores data to the cache storage.
	*
	* @throws ezcBaseFilePermissionException
	* If the directory to store the cache file could not be created.
	* This exception means most likely that your cache directory
	* has been corrupted by external influences (file permission
	* change).
	* @throws ezcBaseFileIoException
	* If an error occured while writing the data to the cache. If this
	* exception occurs, a serious error occured and your storage might
	* be corruped (e.g. broken network connection, file system broken,
	* ...).
	* @throws ezcCacheInvalidDataException
	* If the data submitted can not be handled by the implementation
	* of {@link ezcCacheStorageFile}. Most implementations can not
	* handle objects and resources.
	* @throws ezcCacheApcException
	* If the data could not be stored in APC.
	*
	* @param string $id Unique identifier
	* @param mixed $data The data to store
	* @param array(string=>string) $attributes Attributes describing the cached data
	* @return string The ID string of the newly cached data
	*/
	public function store( $id, $data, $attributes = array() )
	{
	// Generates the identifier
	$filename = $this->properties['location'] . $this->generateIdentifier( $id, $attributes );

	// Purges the Registry Cache
	if ( isset( $this->registry[$filename] ) )
	{
	unset( $this->registry[$filename] );
	}

	// Deletes the files if it already exists on the filesystem
	if ( file_exists( $filename ) )
	{
	if ( unlink( $filename ) === false )
	{
	throw new ezcBaseFilePermissionException( $filename, ezcBaseFileException::WRITE, 'Could not delete existing cache file.' );
	}
	}

	// Deletes the data from APC if it already exists
	$this->backend->delete( $filename );

	// Prepares the data for filesystem storage
	$dataStr = $this->prepareData( $data );

	// Tries to create the directory on the filesystem
	$dirname = dirname( $filename );
	if ( !is_dir( $dirname )
	&& !mkdir( $dirname, 0777, true ) )
	{
	throw new ezcBaseFilePermissionException( $dirname, ezcBaseFileException::WRITE, 'Could not create directory to store cache file.' );
	}

	// Tries to write the file the filesystem
	if ( @file_put_contents( $filename, $dataStr ) !== strlen( $dataStr ) )
	{
	throw new ezcBaseFileIoException( $filename, ezcBaseFileException::WRITE, 'Could not write data to cache file.' );
	}

	// Tries to set the file permissions
	if ( ezcBaseFeatures::os() !== "Windows" )
	{
	chmod( $filename, $this->options->permissions );
	}

	// Prepares the data for APC storage
	$dataObj = $this->prepareData( $data, true );
	$dataObj->mtime = @filemtime( $filename );
	$dataObj->atime = time();

	// Stores it in APC
	$this->registerIdentifier( $id, $attributes, $filename );
	if ( !$this->backend->store( $filename, $dataObj, $this->properties['options']['ttl'] ) )
	{
	throw new ezcCacheApcException( "APC store failed." );
	}

	// Returns the ID for no good reason
	return $id;
	}

	/**
	* Restores the data from the cache.
	*
	* @param string $id The item ID to restore
	* @param array(string=>string) $attributes Attributes describing the data to restore
	* @param bool $search Whether to search for items if not found directly
	* @return mixed The cached data on success, otherwise false
	*/
	public function restore( $id, $attributes = array(), $search = false )
	{
	// Generates the identifier
	$filename = $this->properties['location'] . $this->generateIdentifier( $id, $attributes );

	// Grabs the data object from the APC
	$dataObj = $this->fetchObject( $filename );
	$useApc = false;

	// Checks the APC object exists
	if ( $dataObj !== false
	&& is_object( $dataObj )
	&& isset( $dataObj->atime ) )
	{
	$useApc = true;
	}

	// Checks the APC object is still valid
	if ( !isset( $this->registry[$filename] )
	&& $useApc === true
	&& time() === $dataObj->atime )
	{
	// Make sure the FileSystem still has the file and that it hasn't changed
	if ( file_exists( $filename ) !== false
	&& @filemtime( $filename ) === $dataObj->mtime )
	{
	$dataObj->atime = time();
	$this->backend->store( $filename, $dataObj, $this->properties['options']['ttl'] );
	}
	else
	{
	$useApc = false;
	$this->backend->delete( $filename );
	}
	}

	// Searches the filesystem for the file
	if ( !isset( $this->registry[$filename] )
	&& $useApc === false
	&& file_exists( $filename ) === false )
	{
	if ( $search === true
	&& count( $files = $this->search( $id, $attributes ) ) === 1 )
	{
	$filename = $files[0][2];
	}
	else
	{
	// There are more elements found during search, so false is returned
	return false;
	}
	}

	// Returns false if no data is stored anywhere
	if ( $useApc === false
	&& file_exists( $filename ) === false )
	{
	// Purges APC
	$this->backend->delete( $filename );

	// Purges Registry Cache
	if ( isset( $this->registry[$filename] ) )
	{
	unset( $this->registry[$filename] );
	}

	return false;
	}

	// Creates a Registry Object -- should only happen once per page load
	if ( !isset( $this->registry[$filename] ) )
	{
	$this->registry[$filename] = new stdClass();
	$this->registry[$filename]->data = false;
	$this->registry[$filename]->mtime = $useApc ? $dataObj->mtime : null;
	$this->registry[$filename]->lifetime = $this->calcLifetime( $filename, $useApc );
	}

	// Purges the data if it is expired
	if ( $this->properties['options']['ttl'] !== false
	&& $this->calcLifetime( $filename, $useApc ) > $this->properties['options']['ttl'] )
	{
	$this->delete( $id, $attributes, false ); // don't search
	return false;
	}

	// Returns the data from the Registry Cache
	if ( $this->registry[$filename]->data !== false )
	{
	return ( $this->registry[$filename]->data );
	}

	// Returns data from APC
	else if ( $useApc === true
	&& ( isset( $dataObj->data ) \|\| is_null( $dataObj->data ) ) )
	{
	$this->registry[$filename]->data = $dataObj->data; // primes the Registry cache
	return ( $dataObj->data );
	}

	// Returns data from the filesystem
	else if ( file_exists( $filename ) !== false )
	{
	// Grabs the data from the filesystem
	$dataStr = $this->fetchData( $filename );

	// Stores it in the Registry Cache
	$this->registry[$filename]->data = $dataStr;

	// Prepares the data for APC storage
	$dataObj = $this->prepareData( $dataStr, true );
	$dataObj->mtime = @filemtime( $filename );
	$dataObj->atime = time();

	// Stores it in APC
	$this->backend->store( $filename, $dataObj, $this->properties['options']['ttl'] );

	// Returns the data
	return ( $dataStr );
	}
	else
	{
	return false;
	}
	}

	/**
	* Deletes the data associated with $id or $attributes from the cache.
	*
	* @throws ezcBaseFilePermissionException
	* If an already existsing cache file could not be unlinked.
	* This exception means most likely that your cache directory
	* has been corrupted by external influences (file permission
	* change).
	*
	* @param string $id The item ID to purge
	* @param array(string=>string) $attributes Attributes describing the data to restore
	* @param bool $search Whether to search for items if not found directly
	*/
	public function delete( $id = null, $attributes = array(), $search = false )
	{
	$location = $this->properties['location'];
	// Generates the identifier
	$filename = $location . $this->generateIdentifier( $id, $attributes );

	// Initializes the array
	$delFiles = array();

	clearstatcache();

	// Checks if the file exists on the filesystem
	if ( file_exists( $filename ) )
	{
	$delFiles[] = array( $id, $attributes, $filename );
	}
	else if ( $search === true )
	{
	$delFiles = $this->search( $id, $attributes );
	}

	$deletedIds = array();
	// Deletes the files
	foreach ( $delFiles as $count => $filename )
	{
	// Deletes from Registry Cache
	if ( isset( $this->registry[$filename[2]] ) )
	{
	unset( $this->registry[$filename[2]] );
	}

	// Deletes from APC
	$this->backend->delete( $filename[2] );
	$this->unRegisterIdentifier( $filename[0], $filename[1], $filename[2], true );
	if ( isset( $this->registry[$location][$filename[0]][$filename[2]] ) )
	{
	unset( $this->registry[$location][$filename[0]][$filename[2]] );
	}

	// Deletes from the filesystem
	if ( @unlink( $filename[2] ) === false )
	{
	throw new ezcBaseFilePermissionException(
	$filename,
	ezcBaseFileException::WRITE,
	'Could not unlink cache file.'
	);
	}
	$deletedIds[] = $filename[0];
	}
	$this->storeSearchRegistry();
	return $deletedIds;
	}

	/**
	* Checks the path in the location property exists, and is read-/writable. It
	* throws an exception if not.
	*
	* @throws ezcBaseFileNotFoundException
	* If the storage location does not exist. This should usually not
	* happen, since {@link ezcCacheManager::createCache()} already
	* performs sanity checks for the cache location. In case this
	* exception is thrown, your cache location has been corrupted
	* after the cache was configured.
	* @throws ezcBaseFileNotFoundException
	* If the storage location is not a directory. This should usually
	* not happen, since {@link ezcCacheManager::createCache()} already
	* performs sanity checks for the cache location. In case this
	* exception is thrown, your cache location has been corrupted
	* after the cache was configured.
	* @throws ezcBaseFilePermissionException
	* If the storage location is not writeable. This should usually not
	* happen, since {@link ezcCacheManager::createCache()} already
	* performs sanity checks for the cache location. In case this
	* exception is thrown, your cache location has been corrupted
	* after the cache was configured.
	*/
	protected function validateLocation()
	{
	if ( file_exists( $this->properties['location'] ) === false )
	{
	throw new ezcBaseFileNotFoundException( $this->properties['location'], 'cache location' );
	}

	if ( is_dir( $this->properties['location'] ) === false )
	{
	throw new ezcBaseFileNotFoundException( $this->properties['location'], 'cache location', 'Cache location not a directory.' );
	}

	if ( is_writeable( $this->properties['location'] ) === false )
	{
	throw new ezcBaseFilePermissionException( $this->properties['location'], ezcBaseFileException::WRITE, 'Cache location is not a directory.' );
	}
	}

	/**
	* Calculates the lifetime remaining for a cache object.
	*
	* If the TTL option is set to false, this method will always return 1 for
	* existing items.
	*
	* @param string $filename The file to calculate the remaining lifetime for
	* @param bool $useApc Use APC or not
	* @return int The remaining lifetime in seconds (0 if no time remaining)
	*/
	protected function calcLifetime( $filename, $useApc = false )
	{
	$ttl = $this->options->ttl;
	// Calculate when the APC object was created
	if ( $useApc === true )
	{
	// we've likely already looked this thing up in APC, so we'll grab the local object
	if ( isset( $this->registry[$filename] ) )
	{
	$dataObj = $this->registry[$filename];
	}
	else // otherwise we'll grab it from APC
	{
	$dataObj = $this->fetchObject( $filename );
	}

	if ( is_object( $dataObj ) )
	{
	if ( $ttl === false )
	{
	return 1;
	}
	return (
	( $lifeTime = ( time() - $dataObj->mtime ) ) > $ttl
	? $ttl - $lifeTime
	: 0
	);
	}
	else
	{
	return 0;
	}
	}

	// Calculate when the filesystem file was created
	else
	{
	if ( ( file_exists( $filename ) !== false )
	&& ( ( $modTime = @filemtime( $filename ) ) !== false ) )
	{
	if ( $ttl === false )
	{
	return 1;
	}
	return (
	( $lifeTime = ( time() - $modTime ) ) < $ttl
	? $ttl - $lifeTime
	: 0
	);
	}
	else
	{
	return 0;
	}
	}
	}
	}
	?>