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<?php defined('SYSPATH') or die('No direct script access.');
/**
* File-based Cache driver.
*
* $Id$
*
* @package Cache
* @author Kohana Team
* @copyright (c) 2007-2008 Kohana Team
* @license http://kohanaphp.com/license.html
*/
class Cache_File_Driver implements Cache_Driver {
protected $directory = '';
/**
* Tests that the storage location is a directory and is writable.
*/
public function __construct($directory)
{
// Find the real path to the directory
$directory = str_replace('\\', '/', realpath($directory)).'/';
// Make sure the cache directory is writable
if ( ! is_dir($directory) OR ! is_writable($directory))
throw new Kohana_Exception('cache.unwritable', $directory);
// Directory is valid
$this->directory = $directory;
}
/**
* Finds an array of files matching the given id or tag.
*
* @param string cache id or tag
* @param bool search for tags
* @return array of filenames matching the id or tag
* @return void if no matching files are found
*/
public function exists($id, $tag = FALSE)
{
if ($id === TRUE)
{
// Find all the files
$files = glob($this->directory.'*~*~*');
}
elseif ($tag == TRUE)
{
// Find all the files that have the tag name
$files = glob($this->directory.'*~*'.$id.'*~*');
// Find all tags matching the given tag
foreach ($files as $i => $file)
{
// Split the files
$tags = explode('~', $file);
// Find valid tags
if (count($tags) !== 3 OR empty($tags[1]))
continue;
// Split the tags by plus signs, used to separate tags
$tags = explode('+', $tags[1]);
if ( ! in_array($tag, $tags))
{
// This entry does not match the tag
unset($files[$i]);
}
}
}
else
{
// Find all the files matching the given id
$files = glob($this->directory.$id.'~*');
}
return empty($files) ? NULL : $files;
}
/**
* Sets a cache item to the given data, tags, and lifetime.
*
* @param string cache id to set
* @param string data in the cache
* @param array cache tags
* @param integer lifetime
* @return bool
*/
public function set($id, $data, $tags, $lifetime)
{
// Remove old cache files
$this->delete($id);
// Cache File driver expects unix timestamp
if ($lifetime !== 0)
{
$lifetime += time();
}
// Construct the filename
$filename = $id.'~'.implode('+', $tags).'~'.$lifetime;
// Write the file, appending the sha1 signature to the beginning of the data
return (bool) file_put_contents($this->directory.$filename, sha1($data).$data);
}
/**
* Finds an array of ids for a given tag.
*
* @param string tag name
* @return array of ids that match the tag
*/
public function find($tag)
{
if ($files = $this->exists($tag, TRUE))
{
// Length of directory name
$offset = strlen($this->directory);
// Find all the files with the given tag
$array = array();
foreach ($files as $file)
{
// Get the id from the filename
$array[] = substr(current(explode('~', $file)), $offset);
}
return $array;
}
return FALSE;
}
/**
* Fetches a cache item. This will delete the item if it is expired or if
* the hash does not match the stored hash.
*
* @param string cache id
* @return mixed|NULL
*/
public function get($id)
{
if ($file = $this->exists($id))
{
// Always process the first result
$file = current($file);
// Validate that the cache has not expired
if ($this->expired($file))
{
// Remove this cache, it has expired
$this->delete($id);
}
else
{
$data = file_get_contents($file);
// Find the hash of the data
$hash = substr($data, 0, 40);
// Remove the hash from the data
$data = substr($data, 40);
if ($hash !== sha1($data))
{
// Remove this cache, it doesn't validate
$this->delete($id);
// Unset data to prevent it from being returned
unset($data);
}
}
}
// Return NULL if there is no data
return isset($data) ? $data : NULL;
}
/**
* Deletes a cache item by id or tag
*
* @param string cache id or tag, or TRUE for "all items"
* @param boolean use tags
* @return boolean
*/
public function delete($id, $tag = FALSE)
{
$files = $this->exists($id, $tag);
if (empty($files))
return FALSE;
// Disable all error reporting while deleting
$ER = error_reporting(0);
foreach ($files as $file)
{
// Remove the cache file
if ( ! unlink($file))
Kohana::log('error', 'Cache: Unable to delete cache file: '.$file);
}
// Turn on error reporting again
error_reporting($ER);
return TRUE;
}
/**
* Deletes all cache files that are older than the current time.
*
* @return void
*/
public function delete_expired()
{
if ($files = $this->exists(TRUE))
{
foreach ($files as $file)
{
if ($this->expired($file))
{
// The cache file has already expired, delete it
@unlink($file) or Kohana::log('error', 'Cache: Unable to delete cache file: '.$file);
}
}
}
}
/**
* Check if a cache file has expired by filename.
*
* @param string filename
* @return bool
*/
protected function expired($file)
{
// Get the expiration time
$expires = (int) substr($file, strrpos($file, '~') + 1);
// Expirations of 0 are "never expire"
return ($expires !== 0 AND $expires <= time());
}
} // End Cache File Driver
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