Kohana v3.3.0

modules/cache/classes/Cache.php

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+<?php defined('SYSPATH') or die('No direct script access.');
+
+abstract class Cache extends Kohana_Cache {}

modules/cache/classes/Cache/Apc.php

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+<?php defined('SYSPATH') or die('No direct script access.');
+
+class Cache_Apc extends Kohana_Cache_Apc {}

modules/cache/classes/Cache/Arithmetic.php

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+<?php defined('SYSPATH') or die('No direct script access.');
+
+interface Cache_Arithmetic extends Kohana_Cache_Arithmetic {}

modules/cache/classes/Cache/Exception.php

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+<?php defined('SYSPATH') or die('No direct script access.');
+
+class Cache_Exception extends Kohana_Cache_Exception {}

modules/cache/classes/Cache/File.php

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+<?php defined('SYSPATH') or die('No direct script access.');
+
+class Cache_File extends Kohana_Cache_File {}

modules/cache/classes/Cache/GarbageCollect.php

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+<?php defined('SYSPATH') or die('No direct script access.');
+
+interface Cache_GarbageCollect extends Kohana_Cache_GarbageCollect {}

modules/cache/classes/Cache/Memcache.php

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+<?php defined('SYSPATH') or die('No direct script access.');
+
+class Cache_Memcache extends Kohana_Cache_Memcache {}

modules/cache/classes/Cache/MemcacheTag.php

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+<?php defined('SYSPATH') or die('No direct script access.');
+
+class Cache_MemcacheTag extends Kohana_Cache_MemcacheTag {}

modules/cache/classes/Cache/Sqlite.php

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+<?php defined('SYSPATH') or die('No direct script access.');
+
+class Cache_Sqlite extends Kohana_Cache_Sqlite {}

modules/cache/classes/Cache/Tagging.php

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+<?php defined('SYSPATH') or die('No direct script access.');
+
+interface Cache_Tagging extends Kohana_Cache_Tagging {}

modules/cache/classes/Cache/Wincache.php

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+<?php defined('SYSPATH') or die('No direct script access.');
+
+class Cache_Wincache extends Kohana_Cache_Wincache {}

modules/cache/classes/HTTP/Cache.php

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+<?php defined('SYSPATH') or die('No direct script access.');
+
+class HTTP_Cache extends Kohana_HTTP_Cache {}

modules/cache/classes/Kohana/Cache.php

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+<?php defined('SYSPATH') or die('No direct script access.');
+/**
+ * Kohana Cache provides a common interface to a variety of caching engines. Tags are
+ * supported where available natively to the cache system. Kohana Cache supports multiple
+ * instances of cache engines through a grouped singleton pattern.
+ *
+ * ### Supported cache engines
+ *
+ * *  [APC](http://php.net/manual/en/book.apc.php)
+ * *  [eAccelerator](http://eaccelerator.net/)
+ * *  File
+ * *  [Memcache](http://memcached.org/)
+ * *  [Memcached-tags](http://code.google.com/p/memcached-tags/)
+ * *  [SQLite](http://www.sqlite.org/)
+ * *  [Xcache](http://xcache.lighttpd.net/)
+ *
+ * ### Introduction to caching
+ *
+ * Caching should be implemented with consideration. Generally, caching the result of resources
+ * is faster than reprocessing them. Choosing what, how and when to cache is vital. PHP APC is
+ * presently one of the fastest caching systems available, closely followed by Memcache. SQLite
+ * and File caching are two of the slowest cache methods, however usually faster than reprocessing
+ * a complex set of instructions.
+ *
+ * Caching engines that use memory are considerably faster than the file based alternatives. But
+ * memory is limited whereas disk space is plentiful. If caching large datasets it is best to use
+ * file caching.
+ *
+ * ### Configuration settings
+ *
+ * Kohana Cache uses configuration groups to create cache instances. A configuration group can
+ * use any supported driver, with successive groups using the same driver type if required.
+ *
+ * #### Configuration example
+ *
+ * Below is an example of a _memcache_ server configuration.
+ *
+ *     return array(
+ *          'default'       => array(                      // Default group
+ *                  'driver'         => 'memcache',        // using Memcache driver
+ *                  'servers'        => array(             // Available server definitions
+ *                         array(
+ *                              'host'       => 'localhost',
+ *                              'port'       => 11211,
+ *                              'persistent' => FALSE
+ *                         )
+ *                  ),
+ *                  'compression'    => FALSE,             // Use compression?
+ *           ),
+ *     )
+ *
+ * In cases where only one cache group is required, if the group is named `default` there is
+ * no need to pass the group name when instantiating a cache instance.
+ *
+ * #### General cache group configuration settings
+ *
+ * Below are the settings available to all types of cache driver.
+ *
+ * Name           | Required | Description
+ * -------------- | -------- | ---------------------------------------------------------------
+ * driver         | __YES__  | (_string_) The driver type to use
+ *
+ * Details of the settings specific to each driver are available within the drivers documentation.
+ *
+ * ### System requirements
+ *
+ * *  Kohana 3.0.x
+ * *  PHP 5.2.4 or greater
+ *
+ * @package    Kohana/Cache
+ * @category   Base
+ * @version    2.0
+ * @author     Kohana Team
+ * @copyright  (c) 2009-2012 Kohana Team
+ * @license    http://kohanaphp.com/license
+ */
+abstract class Kohana_Cache {
+
+	const DEFAULT_EXPIRE = 3600;
+
+	/**
+	 * @var   string     default driver to use
+	 */
+	public static $default = 'file';
+
+	/**
+	 * @var   Kohana_Cache instances
+	 */
+	public static $instances = array();
+
+	/**
+	 * Creates a singleton of a Kohana Cache group. If no group is supplied
+	 * the __default__ cache group is used.
+	 *
+	 *     // Create an instance of the default group
+	 *     $default_group = Cache::instance();
+	 *
+	 *     // Create an instance of a group
+	 *     $foo_group = Cache::instance('foo');
+	 *
+	 *     // Access an instantiated group directly
+	 *     $foo_group = Cache::$instances['default'];
+	 *
+	 * @param   string  $group  the name of the cache group to use [Optional]
+	 * @return  Cache
+	 * @throws  Cache_Exception
+	 */
+	public static function instance($group = NULL)
+	{
+		// If there is no group supplied
+		if ($group === NULL)
+		{
+			// Use the default setting
+			$group = Cache::$default;
+		}
+
+		if (isset(Cache::$instances[$group]))
+		{
+			// Return the current group if initiated already
+			return Cache::$instances[$group];
+		}
+
+		$config = Kohana::$config->load('cache');
+
+		if ( ! $config->offsetExists($group))
+		{
+			throw new Cache_Exception(
+				'Failed to load Kohana Cache group: :group',
+				array(':group' => $group)
+			);
+		}
+
+		$config = $config->get($group);
+
+		// Create a new cache type instance
+		$cache_class = 'Cache_'.ucfirst($config['driver']);
+		Cache::$instances[$group] = new $cache_class($config);
+
+		// Return the instance
+		return Cache::$instances[$group];
+	}
+
+	/**
+	 * @var  Config
+	 */
+	protected $_config = array();
+
+	/**
+	 * Ensures singleton pattern is observed, loads the default expiry
+	 *
+	 * @param  array  $config  configuration
+	 */
+	protected function __construct(array $config)
+	{
+		$this->config($config);
+	}
+
+	/**
+	 * Getter and setter for the configuration. If no argument provided, the
+	 * current configuration is returned. Otherwise the configuration is set
+	 * to this class.
+	 *
+	 *     // Overwrite all configuration
+	 *     $cache->config(array('driver' => 'memcache', '...'));
+	 *
+	 *     // Set a new configuration setting
+	 *     $cache->config('servers', array(
+	 *          'foo' => 'bar',
+	 *          '...'
+	 *          ));
+	 *
+	 *     // Get a configuration setting
+	 *     $servers = $cache->config('servers);
+	 *
+	 * @param   mixed    key to set to array, either array or config path
+	 * @param   mixed    value to associate with key
+	 * @return  mixed
+	 */
+	public function config($key = NULL, $value = NULL)
+	{
+		if ($key === NULL)
+			return $this->_config;
+
+		if (is_array($key))
+		{
+			$this->_config = $key;
+		}
+		else
+		{
+			if ($value === NULL)
+				return Arr::get($this->_config, $key);
+
+			$this->_config[$key] = $value;
+		}
+
+		return $this;
+	}
+
+	/**
+	 * Overload the __clone() method to prevent cloning
+	 *
+	 * @return  void
+	 * @throws  Cache_Exception
+	 */
+	final public function __clone()
+	{
+		throw new Cache_Exception('Cloning of Kohana_Cache objects is forbidden');
+	}
+
+	/**
+	 * Retrieve a cached value entry by id.
+	 *
+	 *     // Retrieve cache entry from default group
+	 *     $data = Cache::instance()->get('foo');
+	 *
+	 *     // Retrieve cache entry from default group and return 'bar' if miss
+	 *     $data = Cache::instance()->get('foo', 'bar');
+	 *
+	 *     // Retrieve cache entry from memcache group
+	 *     $data = Cache::instance('memcache')->get('foo');
+	 *
+	 * @param   string  $id       id of cache to entry
+	 * @param   string  $default  default value to return if cache miss
+	 * @return  mixed
+	 * @throws  Cache_Exception
+	 */
+	abstract public function get($id, $default = NULL);
+
+	/**
+	 * Set a value to cache with id and lifetime
+	 *
+	 *     $data = 'bar';
+	 *
+	 *     // Set 'bar' to 'foo' in default group, using default expiry
+	 *     Cache::instance()->set('foo', $data);
+	 *
+	 *     // Set 'bar' to 'foo' in default group for 30 seconds
+	 *     Cache::instance()->set('foo', $data, 30);
+	 *
+	 *     // Set 'bar' to 'foo' in memcache group for 10 minutes
+	 *     if (Cache::instance('memcache')->set('foo', $data, 600))
+	 *     {
+	 *          // Cache was set successfully
+	 *          return
+	 *     }
+	 *
+	 * @param   string   $id        id of cache entry
+	 * @param   string   $data      data to set to cache
+	 * @param   integer  $lifetime  lifetime in seconds
+	 * @return  boolean
+	 */
+	abstract public function set($id, $data, $lifetime = 3600);
+
+	/**
+	 * Delete a cache entry based on id
+	 *
+	 *     // Delete 'foo' entry from the default group
+	 *     Cache::instance()->delete('foo');
+	 *
+	 *     // Delete 'foo' entry from the memcache group
+	 *     Cache::instance('memcache')->delete('foo')
+	 *
+	 * @param   string  $id  id to remove from cache
+	 * @return  boolean
+	 */
+	abstract public function delete($id);
+
+	/**
+	 * Delete all cache entries.
+	 *
+	 * Beware of using this method when
+	 * using shared memory cache systems, as it will wipe every
+	 * entry within the system for all clients.
+	 *
+	 *     // Delete all cache entries in the default group
+	 *     Cache::instance()->delete_all();
+	 *
+	 *     // Delete all cache entries in the memcache group
+	 *     Cache::instance('memcache')->delete_all();
+	 *
+	 * @return  boolean
+	 */
+	abstract public function delete_all();
+
+	/**
+	 * Replaces troublesome characters with underscores.
+	 *
+	 *     // Sanitize a cache id
+	 *     $id = $this->_sanitize_id($id);
+	 *
+	 * @param   string  $id  id of cache to sanitize
+	 * @return  string
+	 */
+	protected function _sanitize_id($id)
+	{
+		// Change slashes and spaces to underscores
+		return str_replace(array('/', '\\', ' '), '_', $id);
+	}
+}
+// End Kohana_Cache

modules/cache/classes/Kohana/Cache/Apc.php

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+<?php defined('SYSPATH') or die('No direct script access.');
+/**
+ * [Kohana Cache](api/Kohana_Cache) APC driver. Provides an opcode based
+ * driver for the Kohana Cache library.
+ *
+ * ### Configuration example
+ *
+ * Below is an example of an _apc_ server configuration.
+ *
+ *     return array(
+ *          'apc' => array(                          // Driver group
+ *                  'driver'         => 'apc',         // using APC driver
+ *           ),
+ *     )
+ *
+ * In cases where only one cache group is required, if the group is named `default` there is
+ * no need to pass the group name when instantiating a cache instance.
+ *
+ * #### General cache group configuration settings
+ *
+ * Below are the settings available to all types of cache driver.
+ *
+ * Name           | Required | Description
+ * -------------- | -------- | ---------------------------------------------------------------
+ * driver         | __YES__  | (_string_) The driver type to use
+ *
+ * ### System requirements
+ *
+ * *  Kohana 3.0.x
+ * *  PHP 5.2.4 or greater
+ * *  APC PHP extension
+ *
+ * @package    Kohana/Cache
+ * @category   Base
+ * @author     Kohana Team
+ * @copyright  (c) 2009-2012 Kohana Team
+ * @license    http://kohanaphp.com/license
+ */
+class Kohana_Cache_Apc extends Cache implements Cache_Arithmetic {
+
+	/**
+	 * Check for existence of the APC extension This method cannot be invoked externally. The driver must
+	 * be instantiated using the `Cache::instance()` method.
+	 *
+	 * @param  array  $config  configuration
+	 * @throws Cache_Exception
+	 */
+	protected function __construct(array $config)
+	{
+		if ( ! extension_loaded('apc'))
+		{
+			throw new Cache_Exception('PHP APC extension is not available.');
+		}
+
+		parent::__construct($config);
+	}
+
+	/**
+	 * Retrieve a cached value entry by id.
+	 *
+	 *     // Retrieve cache entry from apc group
+	 *     $data = Cache::instance('apc')->get('foo');
+	 *
+	 *     // Retrieve cache entry from apc group and return 'bar' if miss
+	 *     $data = Cache::instance('apc')->get('foo', 'bar');
+	 *
+	 * @param   string  $id       id of cache to entry
+	 * @param   string  $default  default value to return if cache miss
+	 * @return  mixed
+	 * @throws  Cache_Exception
+	 */
+	public function get($id, $default = NULL)
+	{
+		$data = apc_fetch($this->_sanitize_id($id), $success);
+
+		return $success ? $data : $default;
+	}
+
+	/**
+	 * Set a value to cache with id and lifetime
+	 *
+	 *     $data = 'bar';
+	 *
+	 *     // Set 'bar' to 'foo' in apc group, using default expiry
+	 *     Cache::instance('apc')->set('foo', $data);
+	 *
+	 *     // Set 'bar' to 'foo' in apc group for 30 seconds
+	 *     Cache::instance('apc')->set('foo', $data, 30);
+	 *
+	 * @param   string   $id        id of cache entry
+	 * @param   string   $data      data to set to cache
+	 * @param   integer  $lifetime  lifetime in seconds
+	 * @return  boolean
+	 */
+	public function set($id, $data, $lifetime = NULL)
+	{
+		if ($lifetime === NULL)
+		{
+			$lifetime = Arr::get($this->_config, 'default_expire', Cache::DEFAULT_EXPIRE);
+		}
+
+		return apc_store($this->_sanitize_id($id), $data, $lifetime);
+	}
+
+	/**
+	 * Delete a cache entry based on id
+	 *
+	 *     // Delete 'foo' entry from the apc group
+	 *     Cache::instance('apc')->delete('foo');
+	 *
+	 * @param   string  $id  id to remove from cache
+	 * @return  boolean
+	 */
+	public function delete($id)
+	{
+		return apc_delete($this->_sanitize_id($id));
+	}
+
+	/**
+	 * Delete all cache entries.
+	 *
+	 * Beware of using this method when
+	 * using shared memory cache systems, as it will wipe every
+	 * entry within the system for all clients.
+	 *
+	 *     // Delete all cache entries in the apc group
+	 *     Cache::instance('apc')->delete_all();
+	 *
+	 * @return  boolean
+	 */
+	public function delete_all()
+	{
+		return apc_clear_cache('user');
+	}
+
+	/**
+	 * Increments a given value by the step value supplied.
+	 * Useful for shared counters and other persistent integer based
+	 * tracking.
+	 *
+	 * @param   string    id of cache entry to increment
+	 * @param   int       step value to increment by
+	 * @return  integer
+	 * @return  boolean
+	 */
+	public function increment($id, $step = 1)
+	{
+		return apc_inc($id, $step);
+	}
+
+	/**
+	 * Decrements a given value by the step value supplied.
+	 * Useful for shared counters and other persistent integer based
+	 * tracking.
+	 *
+	 * @param   string    id of cache entry to decrement
+	 * @param   int       step value to decrement by
+	 * @return  integer
+	 * @return  boolean
+	 */
+	public function decrement($id, $step = 1)
+	{
+		return apc_dec($id, $step);
+	}
+
+} // End Kohana_Cache_Apc

modules/cache/classes/Kohana/Cache/Arithmetic.php

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+<?php defined('SYSPATH') or die('No direct script access.');
+/**
+ * Kohana Cache Arithmetic Interface, for basic cache integer based
+ * arithmetic, addition and subtraction
+ * 
+ * @package    Kohana/Cache
+ * @category   Base
+ * @author     Kohana Team
+ * @copyright  (c) 2009-2012 Kohana Team
+ * @license    http://kohanaphp.com/license
+ * @since      3.2.0
+ */
+interface Kohana_Cache_Arithmetic {
+
+	/**
+	 * Increments a given value by the step value supplied.
+	 * Useful for shared counters and other persistent integer based
+	 * tracking.
+	 *
+	 * @param   string    id of cache entry to increment
+	 * @param   int       step value to increment by
+	 * @return  integer
+	 * @return  boolean
+	 */
+	public function increment($id, $step = 1);
+
+	/**
+	 * Decrements a given value by the step value supplied.
+	 * Useful for shared counters and other persistent integer based
+	 * tracking.
+	 *
+	 * @param   string    id of cache entry to decrement
+	 * @param   int       step value to decrement by
+	 * @return  integer
+	 * @return  boolean
+	 */
+	public function decrement($id, $step = 1);
+
+} // End Kohana_Cache_Arithmetic

modules/cache/classes/Kohana/Cache/Exception.php

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+<?php defined('SYSPATH') or die('No direct script access.');
+/**
+ * Kohana Cache Exception
+ * 
+ * @package    Kohana/Cache
+ * @category   Base
+ * @author     Kohana Team
+ * @copyright  (c) 2009-2012 Kohana Team
+ * @license    http://kohanaphp.com/license
+ */
+class Kohana_Cache_Exception extends Kohana_Exception {}

modules/cache/classes/Kohana/Cache/File.php

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+<?php defined('SYSPATH') or die('No direct script access.');
+/**
+ * [Kohana Cache](api/Kohana_Cache) File driver. Provides a file based
+ * driver for the Kohana Cache library. This is one of the slowest
+ * caching methods.
+ *
+ * ### Configuration example
+ *
+ * Below is an example of a _file_ server configuration.
+ *
+ *     return array(
+ *          'file'   => array(                          // File driver group
+ *                  'driver'         => 'file',         // using File driver
+ *                  'cache_dir'     => APPPATH.'cache/.kohana_cache', // Cache location
+ *           ),
+ *     )
+ *
+ * In cases where only one cache group is required, if the group is named `default` there is
+ * no need to pass the group name when instantiating a cache instance.
+ *
+ * #### General cache group configuration settings
+ *
+ * Below are the settings available to all types of cache driver.
+ *
+ * Name           | Required | Description
+ * -------------- | -------- | ---------------------------------------------------------------
+ * driver         | __YES__  | (_string_) The driver type to use
+ * cache_dir      | __NO__   | (_string_) The cache directory to use for this cache instance
+ *
+ * ### System requirements
+ *
+ * *  Kohana 3.0.x
+ * *  PHP 5.2.4 or greater
+ *
+ * @package    Kohana/Cache
+ * @category   Base
+ * @author     Kohana Team
+ * @copyright  (c) 2009-2012 Kohana Team
+ * @license    http://kohanaphp.com/license
+ */
+class Kohana_Cache_File extends Cache implements Cache_GarbageCollect {
+
+	/**
+	 * Creates a hashed filename based on the string. This is used
+	 * to create shorter unique IDs for each cache filename.
+	 *
+	 *     // Create the cache filename
+	 *     $filename = Cache_File::filename($this->_sanitize_id($id));
+	 *
+	 * @param   string  $string  string to hash into filename
+	 * @return  string
+	 */
+	protected static function filename($string)
+	{
+		return sha1($string).'.cache';
+	}
+
+	/**
+	 * @var  string   the caching directory
+	 */
+	protected $_cache_dir;
+
+	/**
+	 * Constructs the file cache driver. This method cannot be invoked externally. The file cache driver must
+	 * be instantiated using the `Cache::instance()` method.
+	 *
+	 * @param   array  $config  config
+	 * @throws  Cache_Exception
+	 */
+	protected function __construct(array $config)
+	{
+		// Setup parent
+		parent::__construct($config);
+
+		try
+		{
+			$directory = Arr::get($this->_config, 'cache_dir', Kohana::$cache_dir);
+			$this->_cache_dir = new SplFileInfo($directory);
+		}
+		// PHP < 5.3 exception handle
+		catch (ErrorException $e)
+		{
+			$this->_cache_dir = $this->_make_directory($directory, 0777, TRUE);
+		}
+		// PHP >= 5.3 exception handle
+		catch (UnexpectedValueException $e)
+		{
+			$this->_cache_dir = $this->_make_directory($directory, 0777, TRUE);
+		}
+
+		// If the defined directory is a file, get outta here
+		if ($this->_cache_dir->isFile())
+		{
+			throw new Cache_Exception('Unable to create cache directory as a file already exists : :resource', array(':resource' => $this->_cache_dir->getRealPath()));
+		}
+
+		// Check the read status of the directory
+		if ( ! $this->_cache_dir->isReadable())
+		{
+			throw new Cache_Exception('Unable to read from the cache directory :resource', array(':resource' => $this->_cache_dir->getRealPath()));
+		}
+
+		// Check the write status of the directory
+		if ( ! $this->_cache_dir->isWritable())
+		{
+			throw new Cache_Exception('Unable to write to the cache directory :resource', array(':resource' => $this->_cache_dir->getRealPath()));
+		}
+	}
+
+	/**
+	 * Retrieve a cached value entry by id.
+	 *
+	 *     // Retrieve cache entry from file group
+	 *     $data = Cache::instance('file')->get('foo');
+	 *
+	 *     // Retrieve cache entry from file group and return 'bar' if miss
+	 *     $data = Cache::instance('file')->get('foo', 'bar');
+	 *
+	 * @param   string   $id       id of cache to entry
+	 * @param   string   $default  default value to return if cache miss
+	 * @return  mixed
+	 * @throws  Cache_Exception
+	 */
+	public function get($id, $default = NULL)
+	{
+		$filename = Cache_File::filename($this->_sanitize_id($id));
+		$directory = $this->_resolve_directory($filename);
+
+		// Wrap operations in try/catch to handle notices
+		try
+		{
+			// Open file
+			$file = new SplFileInfo($directory.$filename);
+
+			// If file does not exist
+			if ( ! $file->isFile())
+			{
+				// Return default value
+				return $default;
+			}
+			else
+			{
+				// Open the file and parse data
+				$created  = $file->getMTime();
+				$data     = $file->openFile();
+				$lifetime = $data->fgets();
+
+				// If we're at the EOF at this point, corrupted!
+				if ($data->eof())
+				{
+					throw new Cache_Exception(__METHOD__.' corrupted cache file!');
+				}
+
+				$cache = '';
+
+				while ($data->eof() === FALSE)
+				{
+					$cache .= $data->fgets();
+				}
+
+				// Test the expiry
+				if (($created + (int) $lifetime) < time())
+				{
+					// Delete the file
+					$this->_delete_file($file, NULL, TRUE);
+					return $default;
+				}
+				else
+				{
+					return unserialize($cache);
+				}
+			}
+
+		}
+		catch (ErrorException $e)
+		{
+			// Handle ErrorException caused by failed unserialization
+			if ($e->getCode() === E_NOTICE)
+			{
+				throw new Cache_Exception(__METHOD__.' failed to unserialize cached object with message : '.$e->getMessage());
+			}
+
+			// Otherwise throw the exception
+			throw $e;
+		}
+	}
+
+	/**
+	 * Set a value to cache with id and lifetime
+	 *
+	 *     $data = 'bar';
+	 *
+	 *     // Set 'bar' to 'foo' in file group, using default expiry
+	 *     Cache::instance('file')->set('foo', $data);
+	 *
+	 *     // Set 'bar' to 'foo' in file group for 30 seconds
+	 *     Cache::instance('file')->set('foo', $data, 30);
+	 *
+	 * @param   string   $id        id of cache entry
+	 * @param   string   $data      data to set to cache
+	 * @param   integer  $lifetime  lifetime in seconds
+	 * @return  boolean
+	 */
+	public function set($id, $data, $lifetime = NULL)
+	{
+		$filename = Cache_File::filename($this->_sanitize_id($id));
+		$directory = $this->_resolve_directory($filename);
+
+		// If lifetime is NULL
+		if ($lifetime === NULL)
+		{
+			// Set to the default expiry
+			$lifetime = Arr::get($this->_config, 'default_expire', Cache::DEFAULT_EXPIRE);
+		}
+
+		// Open directory
+		$dir = new SplFileInfo($directory);
+
+		// If the directory path is not a directory
+		if ( ! $dir->isDir())
+		{
+			// Create the directory
+			if ( ! mkdir($directory, 0777, TRUE))
+			{
+				throw new Cache_Exception(__METHOD__.' unable to create directory : :directory', array(':directory' => $directory));
+			}
+
+			// chmod to solve potential umask issues
+			chmod($directory, 0777);
+		}
+
+		// Open file to inspect
+		$resouce = new SplFileInfo($directory.$filename);
+		$file = $resouce->openFile('w');
+
+		try
+		{
+			$data = $lifetime."\n".serialize($data);
+			$file->fwrite($data, strlen($data));
+			return (bool) $file->fflush();
+		}
+		catch (ErrorException $e)
+		{
+			// If serialize through an error exception
+			if ($e->getCode() === E_NOTICE)
+			{
+				// Throw a caching error
+				throw new Cache_Exception(__METHOD__.' failed to serialize data for caching with message : '.$e->getMessage());
+			}
+
+			// Else rethrow the error exception
+			throw $e;
+		}
+	}
+
+	/**
+	 * Delete a cache entry based on id
+	 *
+	 *     // Delete 'foo' entry from the file group
+	 *     Cache::instance('file')->delete('foo');
+	 *
+	 * @param   string   $id  id to remove from cache
+	 * @return  boolean
+	 */
+	public function delete($id)
+	{
+		$filename = Cache_File::filename($this->_sanitize_id($id));
+		$directory = $this->_resolve_directory($filename);
+
+		return $this->_delete_file(new SplFileInfo($directory.$filename), NULL, TRUE);
+	}
+
+	/**
+	 * Delete all cache entries.
+	 *
+	 * Beware of using this method when
+	 * using shared memory cache systems, as it will wipe every
+	 * entry within the system for all clients.
+	 *
+	 *     // Delete all cache entries in the file group
+	 *     Cache::instance('file')->delete_all();
+	 *
+	 * @return  boolean
+	 */
+	public function delete_all()
+	{
+		return $this->_delete_file($this->_cache_dir, TRUE);
+	}
+
+	/**
+	 * Garbage collection method that cleans any expired
+	 * cache entries from the cache.
+	 *
+	 * @return  void
+	 */
+	public function garbage_collect()
+	{
+		$this->_delete_file($this->_cache_dir, TRUE, FALSE, TRUE);
+		return;
+	}
+
+	/**
+	 * Deletes files recursively and returns FALSE on any errors
+	 *
+	 *     // Delete a file or folder whilst retaining parent directory and ignore all errors
+	 *     $this->_delete_file($folder, TRUE, TRUE);
+	 *
+	 * @param   SplFileInfo  $file                     file
+	 * @param   boolean      $retain_parent_directory  retain the parent directory
+	 * @param   boolean      $ignore_errors            ignore_errors to prevent all exceptions interrupting exec
+	 * @param   boolean      $only_expired             only expired files
+	 * @return  boolean
+	 * @throws  Cache_Exception
+	 */
+	protected function _delete_file(SplFileInfo $file, $retain_parent_directory = FALSE, $ignore_errors = FALSE, $only_expired = FALSE)
+	{
+		// Allow graceful error handling
+		try
+		{
+			// If is file
+			if ($file->isFile())
+			{
+				try
+				{
+					// Handle ignore files
+					if (in_array($file->getFilename(), $this->config('ignore_on_delete')))
+					{
+						$delete = FALSE;
+					}
+					// If only expired is not set
+					elseif ($only_expired === FALSE)
+					{
+						// We want to delete the file
+						$delete = TRUE;
+					}
+					// Otherwise...
+					else
+					{
+						// Assess the file expiry to flag it for deletion
+						$json = $file->openFile('r')->current();
+						$data = json_decode($json);
+						$delete = $data->expiry < time();
+					}
+
+					// If the delete flag is set delete file
+					if ($delete === TRUE)
+						return unlink($file->getRealPath());
+					else
+						return FALSE;
+				}
+				catch (ErrorException $e)
+				{
+					// Catch any delete file warnings
+					if ($e->getCode() === E_WARNING)
+					{
+						throw new Cache_Exception(__METHOD__.' failed to delete file : :file', array(':file' => $file->getRealPath()));
+					}
+				}
+			}
+			// Else, is directory
+			elseif ($file->isDir())
+			{
+				// Create new DirectoryIterator
+				$files = new DirectoryIterator($file->getPathname());
+
+				// Iterate over each entry
+				while ($files->valid())
+				{
+					// Extract the entry name
+					$name = $files->getFilename();
+
+					// If the name is not a dot
+					if ($name != '.' AND $name != '..')
+					{
+						// Create new file resource
+						$fp = new SplFileInfo($files->getRealPath());
+						// Delete the file
+						$this->_delete_file($fp);
+					}
+
+					// Move the file pointer on
+					$files->next();
+				}
+
+				// If set to retain parent directory, return now
+				if ($retain_parent_directory)
+				{
+					return TRUE;
+				}
+
+				try
+				{
+					// Remove the files iterator
+					// (fixes Windows PHP which has permission issues with open iterators)
+					unset($files);
+
+					// Try to remove the parent directory
+					return rmdir($file->getRealPath());
+				}
+				catch (ErrorException $e)
+				{
+					// Catch any delete directory warnings
+					if ($e->getCode() === E_WARNING)
+					{
+						throw new Cache_Exception(__METHOD__.' failed to delete directory : :directory', array(':directory' => $file->getRealPath()));
+					}
+					throw $e;
+				}
+			}
+			else
+			{
+				// We get here if a file has already been deleted
+				return FALSE;
+			}
+		}
+		// Catch all exceptions
+		catch (Exception $e)
+		{
+			// If ignore_errors is on
+			if ($ignore_errors === TRUE)
+			{
+				// Return
+				return FALSE;
+			}
+			// Throw exception
+			throw $e;
+		}
+	}
+
+	/**
+	 * Resolves the cache directory real path from the filename
+	 *
+	 *      // Get the realpath of the cache folder
+	 *      $realpath = $this->_resolve_directory($filename);
+	 *
+	 * @param   string  $filename  filename to resolve
+	 * @return  string
+	 */
+	protected function _resolve_directory($filename)
+	{
+		return $this->_cache_dir->getRealPath().DIRECTORY_SEPARATOR.$filename[0].$filename[1].DIRECTORY_SEPARATOR;
+	}
+
+	/**
+	 * Makes the cache directory if it doesn't exist. Simply a wrapper for
+	 * `mkdir` to ensure DRY principles
+	 *
+	 * @link    http://php.net/manual/en/function.mkdir.php
+	 * @param   string    $directory
+	 * @param   integer   $mode
+	 * @param   boolean   $recursive
+	 * @param   resource  $context
+	 * @return  SplFileInfo
+	 * @throws  Cache_Exception
+	 */
+	protected function _make_directory($directory, $mode = 0777, $recursive = FALSE, $context = NULL)
+	{
+		if ( ! mkdir($directory, $mode, $recursive, $context))
+		{
+			throw new Cache_Exception('Failed to create the defined cache directory : :directory', array(':directory' => $directory));
+		}
+		chmod($directory, $mode);
+
+		return new SplFileInfo($directory);
+	}
+}

modules/cache/classes/Kohana/Cache/GarbageCollect.php

@@ -0,0 +1,23 @@
+<?php defined('SYSPATH') or die('No direct script access.');
+/**
+ * Garbage Collection interface for caches that have no GC methods
+ * of their own, such as [Cache_File] and [Cache_Sqlite]. Memory based
+ * cache systems clean their own caches periodically.
+ *
+ * @package    Kohana/Cache
+ * @category   Base
+ * @version    2.0
+ * @author     Kohana Team
+ * @copyright  (c) 2009-2012 Kohana Team
+ * @license    http://kohanaphp.com/license
+ * @since      3.0.8
+ */
+interface Kohana_Cache_GarbageCollect {
+	/**
+	 * Garbage collection method that cleans any expired
+	 * cache entries from the cache.
+	 *
+	 * @return void
+	 */
+	public function garbage_collect();
+}

modules/cache/classes/Kohana/Cache/Memcache.php

@@ -0,0 +1,354 @@
+<?php defined('SYSPATH') or die('No direct script access.');
+/**
+ * [Kohana Cache](api/Kohana_Cache) Memcache driver,
+ *
+ * ### Supported cache engines
+ *
+ * *  [Memcache](http://www.php.net/manual/en/book.memcache.php)
+ * *  [Memcached-tags](http://code.google.com/p/memcached-tags/)
+ *
+ * ### Configuration example
+ *
+ * Below is an example of a _memcache_ server configuration.
+ *
+ *     return array(
+ *          'default'   => array(                          // Default group
+ *                  'driver'         => 'memcache',        // using Memcache driver
+ *                  'servers'        => array(             // Available server definitions
+ *                         // First memcache server server
+ *                         array(
+ *                              'host'             => 'localhost',
+ *                              'port'             => 11211,
+ *                              'persistent'       => FALSE
+ *                              'weight'           => 1,
+ *                              'timeout'          => 1,
+ *                              'retry_interval'   => 15,
+ *                              'status'           => TRUE,
+ *				'instant_death'	   => TRUE,
+ *                              'failure_callback' => array('className', 'classMethod')
+ *                         ),
+ *                         // Second memcache server
+ *                         array(
+ *                              'host'             => '192.168.1.5',
+ *                              'port'             => 22122,
+ *                              'persistent'       => TRUE
+ *                         )
+ *                  ),
+ *                  'compression'    => FALSE,             // Use compression?
+ *           ),
+ *     )
+ *
+ * In cases where only one cache group is required, if the group is named `default` there is
+ * no need to pass the group name when instantiating a cache instance.
+ *
+ * #### General cache group configuration settings
+ *
+ * Below are the settings available to all types of cache driver.
+ *
+ * Name           | Required | Description
+ * -------------- | -------- | ---------------------------------------------------------------
+ * driver         | __YES__  | (_string_) The driver type to use
+ * servers        | __YES__  | (_array_) Associative array of server details, must include a __host__ key. (see _Memcache server configuration_ below)
+ * compression    | __NO__   | (_boolean_) Use data compression when caching
+ *
+ * #### Memcache server configuration
+ *
+ * The following settings should be used when defining each memcache server
+ *
+ * Name             | Required | Description
+ * ---------------- | -------- | ---------------------------------------------------------------
+ * host             | __YES__  | (_string_) The host of the memcache server, i.e. __localhost__; or __127.0.0.1__; or __memcache.domain.tld__
+ * port             | __NO__   | (_integer_) Point to the port where memcached is listening for connections. Set this parameter to 0 when using UNIX domain sockets.  Default __11211__
+ * persistent       | __NO__   | (_boolean_) Controls the use of a persistent connection. Default __TRUE__
+ * weight           | __NO__   | (_integer_) Number of buckets to create for this server which in turn control its probability of it being selected. The probability is relative to the total weight of all servers. Default __1__
+ * timeout          | __NO__   | (_integer_) Value in seconds which will be used for connecting to the daemon. Think twice before changing the default value of 1 second - you can lose all the advantages of caching if your connection is too slow. Default __1__
+ * retry_interval   | __NO__   | (_integer_) Controls how often a failed server will be retried, the default value is 15 seconds. Setting this parameter to -1 disables automatic retry. Default __15__
+ * status           | __NO__   | (_boolean_) Controls if the server should be flagged as online. Default __TRUE__
+ * failure_callback | __NO__   | (_[callback](http://www.php.net/manual/en/language.pseudo-types.php#language.types.callback)_) Allows the user to specify a callback function to run upon encountering an error. The callback is run before failover is attempted. The function takes two parameters, the hostname and port of the failed server. Default __NULL__
+ *
+ * ### System requirements
+ *
+ * *  Kohana 3.0.x
+ * *  PHP 5.2.4 or greater
+ * *  Memcache (plus Memcached-tags for native tagging support)
+ * *  Zlib
+ *
+ * @package    Kohana/Cache
+ * @category   Base
+ * @version    2.0
+ * @author     Kohana Team
+ * @copyright  (c) 2009-2012 Kohana Team
+ * @license    http://kohanaphp.com/license
+ */
+class Kohana_Cache_Memcache extends Cache implements Cache_Arithmetic {
+
+	// Memcache has a maximum cache lifetime of 30 days
+	const CACHE_CEILING = 2592000;
+
+	/**
+	 * Memcache resource
+	 *
+	 * @var Memcache
+	 */
+	protected $_memcache;
+
+	/**
+	 * Flags to use when storing values
+	 *
+	 * @var string
+	 */
+	protected $_flags;
+
+	/**
+	 * The default configuration for the memcached server
+	 *
+	 * @var array
+	 */
+	protected $_default_config = array();
+
+	/**
+	 * Constructs the memcache Kohana_Cache object
+	 *
+	 * @param   array  $config  configuration
+	 * @throws  Cache_Exception
+	 */
+	protected function __construct(array $config)
+	{
+		// Check for the memcache extention
+		if ( ! extension_loaded('memcache'))
+		{
+			throw new Cache_Exception('Memcache PHP extention not loaded');
+		}
+
+		parent::__construct($config);
+
+		// Setup Memcache
+		$this->_memcache = new Memcache;
+
+		// Load servers from configuration
+		$servers = Arr::get($this->_config, 'servers', NULL);
+
+		if ( ! $servers)
+		{
+			// Throw an exception if no server found
+			throw new Cache_Exception('No Memcache servers defined in configuration');
+		}
+
+		// Setup default server configuration
+		$this->_default_config = array(
+				'host'             => 'localhost',
+				'port'             => 11211,
+				'persistent'       => FALSE,
+				'weight'           => 1,
+				'timeout'          => 1,
+				'retry_interval'   => 15,
+				'status'           => TRUE,
+				'instant_death'	   => TRUE,
+				'failure_callback' => array($this, '_failed_request'),
+		);
+
+		// Add the memcache servers to the pool
+		foreach ($servers as $server)
+		{
+			// Merge the defined config with defaults
+			$server += $this->_default_config;
+
+			if ( ! $this->_memcache->addServer($server['host'], $server['port'], $server['persistent'], $server['weight'], $server['timeout'], $server['retry_interval'], $server['status'], $server['failure_callback']))
+			{
+				throw new Cache_Exception('Memcache could not connect to host \':host\' using port \':port\'', array(':host' => $server['host'], ':port' => $server['port']));
+			}
+		}
+
+		// Setup the flags
+		$this->_flags = Arr::get($this->_config, 'compression', FALSE) ? MEMCACHE_COMPRESSED : FALSE;
+	}
+
+	/**
+	 * Retrieve a cached value entry by id.
+	 *
+	 *     // Retrieve cache entry from memcache group
+	 *     $data = Cache::instance('memcache')->get('foo');
+	 *
+	 *     // Retrieve cache entry from memcache group and return 'bar' if miss
+	 *     $data = Cache::instance('memcache')->get('foo', 'bar');
+	 *
+	 * @param   string  $id       id of cache to entry
+	 * @param   string  $default  default value to return if cache miss
+	 * @return  mixed
+	 * @throws  Cache_Exception
+	 */
+	public function get($id, $default = NULL)
+	{
+		// Get the value from Memcache
+		$value = $this->_memcache->get($this->_sanitize_id($id));
+
+		// If the value wasn't found, normalise it
+		if ($value === FALSE)
+		{
+			$value = (NULL === $default) ? NULL : $default;
+		}
+
+		// Return the value
+		return $value;
+	}
+
+	/**
+	 * Set a value to cache with id and lifetime
+	 *
+	 *     $data = 'bar';
+	 *
+	 *     // Set 'bar' to 'foo' in memcache group for 10 minutes
+	 *     if (Cache::instance('memcache')->set('foo', $data, 600))
+	 *     {
+	 *          // Cache was set successfully
+	 *          return
+	 *     }
+	 *
+	 * @param   string   $id        id of cache entry
+	 * @param   mixed    $data      data to set to cache
+	 * @param   integer  $lifetime  lifetime in seconds, maximum value 2592000
+	 * @return  boolean
+	 */
+	public function set($id, $data, $lifetime = 3600)
+	{
+		// If the lifetime is greater than the ceiling
+		if ($lifetime > Cache_Memcache::CACHE_CEILING)
+		{
+			// Set the lifetime to maximum cache time
+			$lifetime = Cache_Memcache::CACHE_CEILING + time();
+		}
+		// Else if the lifetime is greater than zero
+		elseif ($lifetime > 0)
+		{
+			$lifetime += time();
+		}
+		// Else
+		else
+		{
+			// Normalise the lifetime
+			$lifetime = 0;
+		}
+
+		// Set the data to memcache
+		return $this->_memcache->set($this->_sanitize_id($id), $data, $this->_flags, $lifetime);
+	}
+
+	/**
+	 * Delete a cache entry based on id
+	 *
+	 *     // Delete the 'foo' cache entry immediately
+	 *     Cache::instance('memcache')->delete('foo');
+	 *
+	 *     // Delete the 'bar' cache entry after 30 seconds
+	 *     Cache::instance('memcache')->delete('bar', 30);
+	 *
+	 * @param   string   $id       id of entry to delete
+	 * @param   integer  $timeout  timeout of entry, if zero item is deleted immediately, otherwise the item will delete after the specified value in seconds
+	 * @return  boolean
+	 */
+	public function delete($id, $timeout = 0)
+	{
+		// Delete the id
+		return $this->_memcache->delete($this->_sanitize_id($id), $timeout);
+	}
+
+	/**
+	 * Delete all cache entries.
+	 *
+	 * Beware of using this method when
+	 * using shared memory cache systems, as it will wipe every
+	 * entry within the system for all clients.
+	 *
+	 *     // Delete all cache entries in the default group
+	 *     Cache::instance('memcache')->delete_all();
+	 *
+	 * @return  boolean
+	 */
+	public function delete_all()
+	{
+		$result = $this->_memcache->flush();
+
+		// We must sleep after flushing, or overwriting will not work!
+		// @see http://php.net/manual/en/function.memcache-flush.php#81420
+		sleep(1);
+
+		return $result;
+	}
+
+	/**
+	 * Callback method for Memcache::failure_callback to use if any Memcache call
+	 * on a particular server fails. This method switches off that instance of the
+	 * server if the configuration setting `instant_death` is set to `TRUE`.
+	 *
+	 * @param   string   $hostname
+	 * @param   integer  $port
+	 * @return  void|boolean
+	 * @since   3.0.8
+	 */
+	public function _failed_request($hostname, $port)
+	{
+		if ( ! $this->_config['instant_death'])
+			return;
+
+		// Setup non-existent host
+		$host = FALSE;
+
+		// Get host settings from configuration
+		foreach ($this->_config['servers'] as $server)
+		{
+			// Merge the defaults, since they won't always be set
+			$server += $this->_default_config;
+			// We're looking at the failed server
+			if ($hostname == $server['host'] and $port == $server['port'])
+			{
+				// Server to disable, since it failed
+				$host = $server;
+				continue;
+			}
+		}
+
+		if ( ! $host)
+			return;
+		else
+		{
+			return $this->_memcache->setServerParams(
+				$host['host'],
+				$host['port'],
+				$host['timeout'],
+				$host['retry_interval'],
+				FALSE, // Server is offline
+				array($this, '_failed_request'
+				));
+		}
+	}
+
+	/**
+	 * Increments a given value by the step value supplied.
+	 * Useful for shared counters and other persistent integer based
+	 * tracking.
+	 *
+	 * @param   string    id of cache entry to increment
+	 * @param   int       step value to increment by
+	 * @return  integer
+	 * @return  boolean
+	 */
+	public function increment($id, $step = 1)
+	{
+		return $this->_memcache->increment($id, $step);
+	}
+
+	/**
+	 * Decrements a given value by the step value supplied.
+	 * Useful for shared counters and other persistent integer based
+	 * tracking.
+	 *
+	 * @param   string    id of cache entry to decrement
+	 * @param   int       step value to decrement by
+	 * @return  integer
+	 * @return  boolean
+	 */
+	public function decrement($id, $step = 1)
+	{
+		return $this->_memcache->decrement($id, $step);
+	}
+}

modules/cache/classes/Kohana/Cache/MemcacheTag.php

@@ -0,0 +1,78 @@
+<?php defined('SYSPATH') or die('No direct script access.');
+/**
+ * See [Kohana_Cache_Memcache]
+ *
+* @package    Kohana/Cache
+* @category   Base
+* @version    2.0
+* @author     Kohana Team
+* @copyright  (c) 2009-2012 Kohana Team
+* @license    http://kohanaphp.com/license
+ */
+class Kohana_Cache_MemcacheTag extends Cache_Memcache implements Cache_Tagging {
+
+	/**
+	 * Constructs the memcache object
+	 *
+	 * @param  array  $config  configuration
+	 * @throws  Cache_Exception
+	 */
+	protected function __construct(array $config)
+	{
+		parent::__construct($config);
+
+		if ( ! method_exists($this->_memcache, 'tag_add'))
+		{
+			throw new Cache_Exception('Memcached-tags PHP plugin not present. Please see http://code.google.com/p/memcached-tags/ for more information');
+		}
+	}
+
+	/**
+	 * Set a value based on an id with tags
+	 *
+	 * @param   string   $id        id
+	 * @param   mixed    $data      data
+	 * @param   integer  $lifetime  lifetime [Optional]
+	 * @param   array    $tags      tags [Optional]
+	 * @return  boolean
+	 */
+	public function set_with_tags($id, $data, $lifetime = NULL, array $tags = NULL)
+	{
+		$id = $this->_sanitize_id($id);
+
+		$result = $this->set($id, $data, $lifetime);
+
+		if ($result and $tags)
+		{
+			foreach ($tags as $tag)
+			{
+				$this->_memcache->tag_add($tag, $id);
+			}
+		}
+
+		return $result;
+	}
+
+	/**
+	 * Delete cache entries based on a tag
+	 *
+	 * @param   string  $tag  tag
+	 * @return  boolean
+	 */
+	public function delete_tag($tag)
+	{
+		return $this->_memcache->tag_delete($tag);
+	}
+
+	/**
+	 * Find cache entries based on a tag
+	 *
+	 * @param   string  $tag  tag
+	 * @return  void
+	 * @throws  Cache_Exception
+	 */
+	public function find($tag)
+	{
+		throw new Cache_Exception('Memcached-tags does not support finding by tag');
+	}
+}

modules/cache/classes/Kohana/Cache/Sqlite.php

@@ -0,0 +1,334 @@
+<?php defined('SYSPATH') or die('No direct script access.');
+/**
+ * Kohana Cache Sqlite Driver
+ *
+ * Requires SQLite3 and PDO
+ *
+ * @package    Kohana/Cache
+ * @category   Base
+ * @author     Kohana Team
+ * @copyright  (c) 2009-2012 Kohana Team
+ * @license    http://kohanaphp.com/license
+ */
+class Kohana_Cache_Sqlite extends Cache implements Cache_Tagging, Cache_GarbageCollect {
+
+	/**
+	 * Database resource
+	 *
+	 * @var  PDO
+	 */
+	protected $_db;
+
+	/**
+	 * Sets up the PDO SQLite table and
+	 * initialises the PDO connection
+	 *
+	 * @param  array  $config  configuration
+	 * @throws  Cache_Exception
+	 */
+	protected function __construct(array $config)
+	{
+		parent::__construct($config);
+
+		$database = Arr::get($this->_config, 'database', NULL);
+
+		if ($database === NULL)
+		{
+			throw new Cache_Exception('Database path not available in Kohana Cache configuration');
+		}
+
+		// Load new Sqlite DB
+		$this->_db = new PDO('sqlite:'.$database);
+
+		// Test for existing DB
+		$result = $this->_db->query("SELECT * FROM sqlite_master WHERE name = 'caches' AND type = 'table'")->fetchAll();
+
+		// If there is no table, create a new one
+		if (0 == count($result))
+		{
+			$database_schema = Arr::get($this->_config, 'schema', NULL);
+
+			if ($database_schema === NULL)
+			{
+				throw new Cache_Exception('Database schema not found in Kohana Cache configuration');
+			}
+
+			try
+			{
+				// Create the caches table
+				$this->_db->query(Arr::get($this->_config, 'schema', NULL));
+			}
+			catch (PDOException $e)
+			{
+				throw new Cache_Exception('Failed to create new SQLite caches table with the following error : :error', array(':error' => $e->getMessage()));
+			}
+		}
+	}
+
+	/**
+	 * Retrieve a value based on an id
+	 *
+	 * @param   string  $id       id
+	 * @param   string  $default  default [Optional] Default value to return if id not found
+	 * @return  mixed
+	 * @throws  Cache_Exception
+	 */
+	public function get($id, $default = NULL)
+	{
+		// Prepare statement
+		$statement = $this->_db->prepare('SELECT id, expiration, cache FROM caches WHERE id = :id LIMIT 0, 1');
+
+		// Try and load the cache based on id
+		try
+		{
+			$statement->execute(array(':id' => $this->_sanitize_id($id)));
+		}
+		catch (PDOException $e)
+		{
+			throw new Cache_Exception('There was a problem querying the local SQLite3 cache. :error', array(':error' => $e->getMessage()));
+		}
+
+		if ( ! $result = $statement->fetch(PDO::FETCH_OBJ))
+		{
+			return $default;
+		}
+
+		// If the cache has expired
+		if ($result->expiration != 0 and $result->expiration <= time())
+		{
+			// Delete it and return default value
+			$this->delete($id);
+			return $default;
+		}
+		// Otherwise return cached object
+		else
+		{
+			// Disable notices for unserializing
+			$ER = error_reporting(~E_NOTICE);
+
+			// Return the valid cache data
+			$data = unserialize($result->cache);
+
+			// Turn notices back on
+			error_reporting($ER);
+
+			// Return the resulting data
+			return $data;
+		}
+	}
+
+	/**
+	 * Set a value based on an id. Optionally add tags.
+	 *
+	 * @param   string   $id        id
+	 * @param   mixed    $data      data
+	 * @param   integer  $lifetime  lifetime [Optional]
+	 * @return  boolean
+	 */
+	public function set($id, $data, $lifetime = NULL)
+	{
+		return (bool) $this->set_with_tags($id, $data, $lifetime);
+	}
+
+	/**
+	 * Delete a cache entry based on id
+	 *
+	 * @param   string  $id  id
+	 * @return  boolean
+	 * @throws  Cache_Exception
+	 */
+	public function delete($id)
+	{
+		// Prepare statement
+		$statement = $this->_db->prepare('DELETE FROM caches WHERE id = :id');
+
+		// Remove the entry
+		try
+		{
+			$statement->execute(array(':id' => $this->_sanitize_id($id)));
+		}
+		catch (PDOException $e)
+		{
+			throw new Cache_Exception('There was a problem querying the local SQLite3 cache. :error', array(':error' => $e->getMessage()));
+		}
+
+		return (bool) $statement->rowCount();
+	}
+
+	/**
+	 * Delete all cache entries
+	 *
+	 * @return  boolean
+	 */
+	public function delete_all()
+	{
+		// Prepare statement
+		$statement = $this->_db->prepare('DELETE FROM caches');
+
+		// Remove the entry
+		try
+		{
+			$statement->execute();
+		}
+		catch (PDOException $e)
+		{
+			throw new Cache_Exception('There was a problem querying the local SQLite3 cache. :error', array(':error' => $e->getMessage()));
+		}
+
+		return (bool) $statement->rowCount();
+	}
+
+	/**
+	 * Set a value based on an id. Optionally add tags.
+	 *
+	 * @param   string   $id        id
+	 * @param   mixed    $data      data
+	 * @param   integer  $lifetime  lifetime [Optional]
+	 * @param   array    $tags      tags [Optional]
+	 * @return  boolean
+	 * @throws  Cache_Exception
+	 */
+	public function set_with_tags($id, $data, $lifetime = NULL, array $tags = NULL)
+	{
+		// Serialize the data
+		$data = serialize($data);
+
+		// Normalise tags
+		$tags = (NULL === $tags) ? NULL : ('<'.implode('>,<', $tags).'>');
+
+		// Setup lifetime
+		if ($lifetime === NULL)
+		{
+			$lifetime = (0 === Arr::get($this->_config, 'default_expire', NULL)) ? 0 : (Arr::get($this->_config, 'default_expire', Cache::DEFAULT_EXPIRE) + time());
+		}
+		else
+		{
+			$lifetime = (0 === $lifetime) ? 0 : ($lifetime + time());
+		}
+
+		// Prepare statement
+		// $this->exists() may throw Cache_Exception, no need to catch/rethrow
+		$statement = $this->exists($id) ? $this->_db->prepare('UPDATE caches SET expiration = :expiration, cache = :cache, tags = :tags WHERE id = :id') : $this->_db->prepare('INSERT INTO caches (id, cache, expiration, tags) VALUES (:id, :cache, :expiration, :tags)');
+
+		// Try to insert
+		try
+		{
+			$statement->execute(array(':id' => $this->_sanitize_id($id), ':cache' => $data, ':expiration' => $lifetime, ':tags' => $tags));
+		}
+		catch (PDOException $e)
+		{
+			throw new Cache_Exception('There was a problem querying the local SQLite3 cache. :error', array(':error' => $e->getMessage()));
+		}
+
+		return (bool) $statement->rowCount();
+	}
+
+	/**
+	 * Delete cache entries based on a tag
+	 *
+	 * @param   string  $tag  tag
+	 * @return  boolean
+	 * @throws  Cache_Exception
+	 */
+	public function delete_tag($tag)
+	{
+		// Prepare the statement
+		$statement = $this->_db->prepare('DELETE FROM caches WHERE tags LIKE :tag');
+
+		// Try to delete
+		try
+		{
+			$statement->execute(array(':tag' => "%<{$tag}>%"));
+		}
+		catch (PDOException $e)
+		{
+			throw new Cache_Exception('There was a problem querying the local SQLite3 cache. :error', array(':error' => $e->getMessage()));
+		}
+
+		return (bool) $statement->rowCount();
+	}
+
+	/**
+	 * Find cache entries based on a tag
+	 *
+	 * @param   string  $tag  tag
+	 * @return  array
+	 * @throws  Cache_Exception
+	 */
+	public function find($tag)
+	{
+		// Prepare the statement
+		$statement = $this->_db->prepare('SELECT id, cache FROM caches WHERE tags LIKE :tag');
+
+		// Try to find
+		try
+		{
+			if ( ! $statement->execute(array(':tag' => "%<{$tag}>%")))
+			{
+				return array();
+			}
+		}
+		catch (PDOException $e)
+		{
+			throw new Cache_Exception('There was a problem querying the local SQLite3 cache. :error', array(':error' => $e->getMessage()));
+		}
+
+		$result = array();
+
+		while ($row = $statement->fetchObject())
+		{
+			// Disable notices for unserializing
+			$ER = error_reporting(~E_NOTICE);
+
+			$result[$row->id] = unserialize($row->cache);
+
+			// Turn notices back on
+			error_reporting($ER);
+		}
+
+		return $result;
+	}
+
+	/**
+	 * Garbage collection method that cleans any expired
+	 * cache entries from the cache.
+	 *
+	 * @return  void
+	 */
+	public function garbage_collect()
+	{
+		// Create the sequel statement
+		$statement = $this->_db->prepare('DELETE FROM caches WHERE expiration < :expiration');
+
+		try
+		{
+			$statement->execute(array(':expiration' => time()));
+		}
+		catch (PDOException $e)
+		{
+			throw new Cache_Exception('There was a problem querying the local SQLite3 cache. :error', array(':error' => $e->getMessage()));
+		}
+	}
+
+	/**
+	 * Tests whether an id exists or not
+	 *
+	 * @param   string  $id  id
+	 * @return  boolean
+	 * @throws  Cache_Exception
+	 */
+	protected function exists($id)
+	{
+		$statement = $this->_db->prepare('SELECT id FROM caches WHERE id = :id');
+		try
+		{
+			$statement->execute(array(':id' => $this->_sanitize_id($id)));
+		}
+		catch (PDOExeption $e)
+		{
+			throw new Cache_Exception('There was a problem querying the local SQLite3 cache. :error', array(':error' => $e->getMessage()));
+		}
+
+		return (bool) $statement->fetchAll();
+	}
+}

modules/cache/classes/Kohana/Cache/Tagging.php

@@ -0,0 +1,41 @@
+<?php defined('SYSPATH') or die('No direct script access.');
+/**
+ * Kohana Cache Tagging Interface
+ *
+ * @package    Kohana/Cache
+ * @category   Base
+ * @author     Kohana Team
+ * @copyright  (c) 2009-2012 Kohana Team
+ * @license    http://kohanaphp.com/license
+ */
+interface Kohana_Cache_Tagging {
+
+	/**
+	 * Set a value based on an id. Optionally add tags.
+	 *
+	 * Note : Some caching engines do not support
+	 * tagging
+	 *
+	 * @param   string   $id        id
+	 * @param   mixed    $data      data
+	 * @param   integer  $lifetime  lifetime [Optional]
+	 * @param   array    $tags      tags [Optional]
+	 * @return  boolean
+	 */
+	public function set_with_tags($id, $data, $lifetime = NULL, array $tags = NULL);
+
+	/**
+	 * Delete cache entries based on a tag
+	 *
+	 * @param   string  $tag  tag
+	 */
+	public function delete_tag($tag);
+
+	/**
+	 * Find cache entries based on a tag
+	 *
+	 * @param   string  $tag  tag
+	 * @return  array
+	 */
+	public function find($tag);
+}

modules/cache/classes/Kohana/Cache/Wincache.php

@@ -0,0 +1,140 @@
+<?php defined('SYSPATH') or die('No direct script access.');
+/**
+ * [Kohana Cache](api/Kohana_Cache) Wincache driver. Provides an opcode based
+ * driver for the Kohana Cache library.
+ *
+ * ### Configuration example
+ *
+ * Below is an example of an _wincache_ server configuration.
+ *
+ *     return array(
+ *          'wincache' => array(                     // Driver group
+ *                  'driver'         => 'wincache',  // using wincache driver
+ *           ),
+ *     )
+ *
+ * In cases where only one cache group is required, if the group is named `default` there is
+ * no need to pass the group name when instantiating a cache instance.
+ *
+ * #### General cache group configuration settings
+ *
+ * Below are the settings available to all types of cache driver.
+ *
+ * Name           | Required | Description
+ * -------------- | -------- | ---------------------------------------------------------------
+ * driver         | __YES__  | (_string_) The driver type to use
+ *
+ * ### System requirements
+ *
+ * *  Windows XP SP3 with IIS 5.1 and » FastCGI Extension
+ * *  Windows Server 2003 with IIS 6.0 and » FastCGI Extension
+ * *  Windows Vista SP1 with IIS 7.0 and FastCGI Module
+ * *  Windows Server 2008 with IIS 7.0 and FastCGI Module
+ * *  Windows 7 with IIS 7.5 and FastCGI Module
+ * *  Windows Server 2008 R2 with IIS 7.5 and FastCGI Module
+ * *  PHP 5.2.X, Non-thread-safe build
+ * *  PHP 5.3 X86, Non-thread-safe VC9 build
+ *
+ * @package    Kohana/Cache
+ * @category   Base
+ * @author     Kohana Team
+ * @copyright  (c) 2009-2012 Kohana Team
+ * @license    http://kohanaphp.com/license
+ */
+class Kohana_Cache_Wincache extends Cache {
+
+	/**
+	 * Check for existence of the wincache extension This method cannot be invoked externally. The driver must
+	 * be instantiated using the `Cache::instance()` method.
+	 *
+	 * @param  array  $config  configuration
+	 * @throws Cache_Exception
+	 */
+	protected function __construct(array $config)
+	{
+		if ( ! extension_loaded('wincache'))
+		{
+			throw new Cache_Exception('PHP wincache extension is not available.');
+		}
+
+		parent::__construct($config);
+	}
+
+	/**
+	 * Retrieve a cached value entry by id.
+	 *
+	 *     // Retrieve cache entry from wincache group
+	 *     $data = Cache::instance('wincache')->get('foo');
+	 *
+	 *     // Retrieve cache entry from wincache group and return 'bar' if miss
+	 *     $data = Cache::instance('wincache')->get('foo', 'bar');
+	 *
+	 * @param   string  $id       id of cache to entry
+	 * @param   string  $default  default value to return if cache miss
+	 * @return  mixed
+	 * @throws  Cache_Exception
+	 */
+	public function get($id, $default = NULL)
+	{
+		$data = wincache_ucache_get($this->_sanitize_id($id), $success);
+
+		return $success ? $data : $default;
+	}
+
+	/**
+	 * Set a value to cache with id and lifetime
+	 *
+	 *     $data = 'bar';
+	 *
+	 *     // Set 'bar' to 'foo' in wincache group, using default expiry
+	 *     Cache::instance('wincache')->set('foo', $data);
+	 *
+	 *     // Set 'bar' to 'foo' in wincache group for 30 seconds
+	 *     Cache::instance('wincache')->set('foo', $data, 30);
+	 *
+	 * @param   string   $id        id of cache entry
+	 * @param   string   $data      data to set to cache
+	 * @param   integer  $lifetime  lifetime in seconds
+	 * @return  boolean
+	 */
+	public function set($id, $data, $lifetime = NULL)
+	{
+		if ($lifetime === NULL)
+		{
+			$lifetime = Arr::get($this->_config, 'default_expire', Cache::DEFAULT_EXPIRE);
+		}
+
+		return wincache_ucache_set($this->_sanitize_id($id), $data, $lifetime);
+	}
+
+	/**
+	 * Delete a cache entry based on id
+	 *
+	 *     // Delete 'foo' entry from the wincache group
+	 *     Cache::instance('wincache')->delete('foo');
+	 *
+	 * @param   string  $id  id to remove from cache
+	 * @return  boolean
+	 */
+	public function delete($id)
+	{
+		return wincache_ucache_delete($this->_sanitize_id($id));
+	}
+
+	/**
+	 * Delete all cache entries.
+	 *
+	 * Beware of using this method when
+	 * using shared memory cache systems, as it will wipe every
+	 * entry within the system for all clients.
+	 *
+	 *     // Delete all cache entries in the wincache group
+	 *     Cache::instance('wincache')->delete_all();
+	 *
+	 * @return  boolean
+	 */
+	public function delete_all()
+	{
+		return wincache_ucache_clear();
+	}
+}

modules/cache/classes/Kohana/HTTP/Cache.php

@@ -0,0 +1,503 @@
+<?php defined('SYSPATH') or die('No direct script access.');
+/**
+ * HTTT Caching adaptor class that provides caching services to the
+ * [Request_Client] class, using HTTP cache control logic as defined in
+ * RFC 2616.
+ *
+ * @package    Kohana
+ * @category   Base
+ * @author     Kohana Team
+ * @copyright  (c) 2008-2012 Kohana Team
+ * @license    http://kohanaframework.org/license
+ * @since      3.2.0
+ */
+class Kohana_HTTP_Cache {
+
+	const CACHE_STATUS_KEY    = 'x-cache-status';
+	const CACHE_STATUS_SAVED  = 'SAVED';
+	const CACHE_STATUS_HIT    = 'HIT';
+	const CACHE_STATUS_MISS   = 'MISS';
+	const CACHE_HIT_KEY       = 'x-cache-hits';
+
+	/**
+	 * Factory method for HTTP_Cache that provides a convenient dependency
+	 * injector for the Cache library.
+	 * 
+	 *      // Create HTTP_Cache with named cache engine
+	 *      $http_cache = HTTP_Cache::factory('memcache', array(
+	 *          'allow_private_cache' => FALSE
+	 *          )
+	 *      );
+	 * 
+	 *      // Create HTTP_Cache with supplied cache engine
+	 *      $http_cache = HTTP_Cache::factory(Cache::instance('memcache'),
+	 *          array(
+	 *              'allow_private_cache' => FALSE
+	 *          )
+	 *      );
+	 *
+	 * @uses    [Cache]
+	 * @param   mixed   $cache      cache engine to use
+	 * @param   array   $options    options to set to this class
+	 * @return  HTTP_Cache
+	 */
+	public static function factory($cache, array $options = array())
+	{
+		if ( ! $cache instanceof Cache)
+		{
+			$cache = Cache::instance($cache);
+		}
+
+		$options['cache'] = $cache;
+
+		return new HTTP_Cache($options);
+	}
+
+	/**
+	 * Basic cache key generator that hashes the entire request and returns
+	 * it. This is fine for static content, or dynamic content where user
+	 * specific information is encoded into the request.
+	 * 
+	 *      // Generate cache key
+	 *      $cache_key = HTTP_Cache::basic_cache_key_generator($request);
+	 *
+	 * @param   Request $request
+	 * @return  string
+	 */
+	public static function basic_cache_key_generator(Request $request)
+	{
+		$uri     = $request->uri();
+		$query   = $request->query();
+		$headers = $request->headers()->getArrayCopy();
+		$body    = $request->body();
+
+		return sha1($uri.'?'.http_build_query($query, NULL, '&').'~'.implode('~', $headers).'~'.$body);
+	}
+
+	/**
+	 * @var     Cache    cache driver to use for HTTP caching
+	 */
+	protected $_cache;
+
+	/**
+	 * @var    callback  Cache key generator callback
+	 */
+	protected $_cache_key_callback;
+
+	/**
+	 * @var    boolean   Defines whether this client should cache `private` cache directives
+	 * @link   http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9
+	 */
+	protected $_allow_private_cache = FALSE;
+
+	/**
+	 * @var    int       The timestamp of the request
+	 */
+	protected $_request_time;
+
+	/**
+	 * @var    int       The timestamp of the response
+	 */
+	protected $_response_time;
+
+	/**
+	 * Constructor method for this class. Allows dependency injection of the
+	 * required components such as `Cache` and the cache key generator.
+	 *
+	 * @param   array $options 
+	 */
+	public function __construct(array $options = array())
+	{
+		foreach ($options as $key => $value)
+		{
+			if (method_exists($this, $key))
+			{
+				$this->$key($value);
+			}
+		}
+
+		if ($this->_cache_key_callback === NULL)
+		{
+			$this->cache_key_callback('HTTP_Cache::basic_cache_key_generator');
+		}
+	}
+
+	/**
+	 * Executes the supplied [Request] with the supplied [Request_Client].
+	 * Before execution, the HTTP_Cache adapter checks the request type,
+	 * destructive requests such as `POST`, `PUT` and `DELETE` will bypass
+	 * cache completely and ensure the response is not cached. All other
+	 * Request methods will allow caching, if the rules are met.
+	 *
+	 * @param   Request_Client  $client     client to execute with Cache-Control
+	 * @param   Request         $request    request to execute with client
+	 * @return  [Response]
+	 */
+	public function execute(Request_Client $client, Request $request, Response $response)
+	{
+		if ( ! $this->_cache instanceof Cache)
+			return $client->execute_request($request, $response);
+
+		// If this is a destructive request, by-pass cache completely
+		if (in_array($request->method(), array(
+			HTTP_Request::POST, 
+			HTTP_Request::PUT, 
+			HTTP_Request::DELETE)))
+		{
+			// Kill existing caches for this request
+			$this->invalidate_cache($request);
+
+			$response = $client->execute_request($request, $response);
+
+			$cache_control = HTTP_Header::create_cache_control(array(
+				'no-cache',
+				'must-revalidate'
+			));
+
+			// Ensure client respects destructive action
+			return $response->headers('cache-control', $cache_control);
+		}
+
+		// Create the cache key
+		$cache_key = $this->create_cache_key($request, $this->_cache_key_callback);
+
+		// Try and return cached version
+		if (($cached_response = $this->cache_response($cache_key, $request)) instanceof Response)
+			return $cached_response;
+
+		// Start request time
+		$this->_request_time = time();
+
+		// Execute the request with the Request client
+		$response = $client->execute_request($request, $response);
+
+		// Stop response time
+		$this->_response_time = (time() - $this->_request_time);
+
+		// Cache the response
+		$this->cache_response($cache_key, $request, $response);
+
+		$response->headers(HTTP_Cache::CACHE_STATUS_KEY, 
+			HTTP_Cache::CACHE_STATUS_MISS);
+
+		return $response;
+	}
+
+	/**
+	 * Invalidate a cached response for the [Request] supplied.
+	 * This has the effect of deleting the response from the
+	 * [Cache] entry.
+	 *
+	 * @param   Request  $request Response to remove from cache
+	 * @return  void
+	 */
+	public function invalidate_cache(Request $request)
+	{
+		if (($cache = $this->cache()) instanceof Cache)
+		{
+			$cache->delete($this->create_cache_key($request, $this->_cache_key_callback));
+		}
+
+		return;
+	}
+
+	/**
+	 * Getter and setter for the internal caching engine,
+	 * used to cache responses if available and valid.
+	 *
+	 * @param   Kohana_Cache  $cache    engine to use for caching
+	 * @return  Kohana_Cache
+	 * @return  Kohana_Request_Client
+	 */
+	public function cache(Cache $cache = NULL)
+	{
+		if ($cache === NULL)
+			return $this->_cache;
+
+		$this->_cache = $cache;
+		return $this;
+	}
+
+	/**
+	 * Gets or sets the [Request_Client::allow_private_cache] setting.
+	 * If set to `TRUE`, the client will also cache cache-control directives
+	 * that have the `private` setting.
+	 *
+	 * @link    http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9
+	 * @param   boolean $setting    allow caching of privately marked responses
+	 * @return  boolean
+	 * @return  [Request_Client]
+	 */
+	public function allow_private_cache($setting = NULL)
+	{
+		if ($setting === NULL)
+			return $this->_allow_private_cache;
+
+		$this->_allow_private_cache = (bool) $setting;
+		return $this;
+	}
+
+	/**
+	 * Sets or gets the cache key generator callback for this caching
+	 * class. The cache key generator provides a unique hash based on the
+	 * `Request` object passed to it.
+	 * 
+	 * The default generator is [HTTP_Cache::basic_cache_key_generator()], which
+	 * serializes the entire `HTTP_Request` into a unique sha1 hash. This will
+	 * provide basic caching for static and simple dynamic pages. More complex
+	 * algorithms can be defined and then passed into `HTTP_Cache` using this
+	 * method.
+	 * 
+	 *      // Get the cache key callback
+	 *      $callback = $http_cache->cache_key_callback();
+	 * 
+	 *      // Set the cache key callback
+	 *      $http_cache->cache_key_callback('Foo::cache_key');
+	 * 
+	 *      // Alternatively, in PHP 5.3 use a closure
+	 *      $http_cache->cache_key_callback(function (Request $request) {
+	 *            return sha1($request->render());
+	 *      });
+	 *
+	 * @param   callback    $callback
+	 * @return  mixed
+	 * @throws  HTTP_Exception
+	 */
+	public function cache_key_callback($callback = NULL)
+	{
+		if ($callback === NULL)
+			return $this->_cache_key_callback;
+
+		if ( ! is_callable($callback))
+			throw new Kohana_Exception('cache_key_callback must be callable!');
+
+		$this->_cache_key_callback = $callback;
+		return $this;
+	}
+
+	/**
+	 * Creates a cache key for the request to use for caching
+	 * [Kohana_Response] returned by [Request::execute].
+	 * 
+	 * This is the default cache key generating logic, but can be overridden
+	 * by setting [HTTP_Cache::cache_key_callback()].
+	 *
+	 * @param   Request     $request    request to create key for
+	 * @param   callback    $callback   optional callback to use instead of built-in method
+	 * @return  string
+	 */
+	public function create_cache_key(Request $request, $callback = FALSE)
+	{
+		if (is_callable($callback))
+			return call_user_func($callback, $request);
+		else
+			return HTTP_Cache::basic_cache_key_generator($request);
+	}
+
+	/**
+	 * Controls whether the response can be cached. Uses HTTP
+	 * protocol to determine whether the response can be cached.
+	 *
+	 * @link    RFC 2616 http://www.w3.org/Protocols/rfc2616/
+	 * @param   Response  $response The Response
+	 * @return  boolean
+	 */
+	public function set_cache(Response $response)
+	{
+		$headers = $response->headers()->getArrayCopy();
+
+		if ($cache_control = Arr::get($headers, 'cache-control'))
+		{
+			// Parse the cache control
+			$cache_control = HTTP_Header::parse_cache_control($cache_control);
+
+			// If the no-cache or no-store directive is set, return
+			if (array_intersect($cache_control, array('no-cache', 'no-store')))
+				return FALSE;
+
+			// Check for private cache and get out of here if invalid
+			if ( ! $this->_allow_private_cache AND in_array('private', $cache_control))
+			{
+				if ( ! isset($cache_control['s-maxage']))
+					return FALSE;
+
+				// If there is a s-maxage directive we can use that
+				$cache_control['max-age'] = $cache_control['s-maxage'];
+			}
+
+			// Check that max-age has been set and if it is valid for caching
+			if (isset($cache_control['max-age']) AND $cache_control['max-age'] < 1)
+				return FALSE;
+		}
+
+		if ($expires = Arr::get($headers, 'expires') AND ! isset($cache_control['max-age']))
+		{
+			// Can't cache things that have expired already
+			if (strtotime($expires) <= time())
+				return FALSE;
+		}
+
+		return TRUE;
+	}
+
+	/**
+	 * Caches a [Response] using the supplied [Cache]
+	 * and the key generated by [Request_Client::_create_cache_key].
+	 *
+	 * If not response is supplied, the cache will be checked for an existing
+	 * one that is available.
+	 *
+	 * @param   string      $key        the cache key to use
+	 * @param   Request     $request    the HTTP Request
+	 * @param   Response    $response   the HTTP Response
+	 * @return  mixed
+	 */
+	public function cache_response($key, Request $request, Response $response = NULL)
+	{
+		if ( ! $this->_cache instanceof Cache)
+			return FALSE;
+
+		// Check for Pragma: no-cache
+		if ($pragma = $request->headers('pragma'))
+		{
+			if ($pragma  == 'no-cache')
+				return FALSE;
+			elseif (is_array($pragma) AND in_array('no-cache', $pragma))
+				return FALSE;
+		}
+
+		// If there is no response, lookup an existing cached response
+		if ($response === NULL)
+		{
+			$response = $this->_cache->get($key);
+
+			if ( ! $response instanceof Response)
+				return FALSE;
+
+			// Do cache hit arithmetic, using fast arithmetic if available
+			if ($this->_cache instanceof Cache_Arithmetic)
+			{
+				$hit_count = $this->_cache->increment(HTTP_Cache::CACHE_HIT_KEY.$key);
+			}
+			else
+			{
+				$hit_count = $this->_cache->get(HTTP_Cache::CACHE_HIT_KEY.$key);
+				$this->_cache->set(HTTP_Cache::CACHE_HIT_KEY.$key, ++$hit_count);
+			}
+
+			// Update the header to have correct HIT status and count
+			$response->headers(HTTP_Cache::CACHE_STATUS_KEY,
+				HTTP_Cache::CACHE_STATUS_HIT)
+				->headers(HTTP_Cache::CACHE_HIT_KEY, $hit_count);
+
+			return $response;
+		}
+		else
+		{
+			if (($ttl = $this->cache_lifetime($response)) === FALSE)
+				return FALSE;
+
+			$response->headers(HTTP_Cache::CACHE_STATUS_KEY,
+				HTTP_Cache::CACHE_STATUS_SAVED);
+
+			// Set the hit count to zero
+			$this->_cache->set(HTTP_Cache::CACHE_HIT_KEY.$key, 0);
+
+			return $this->_cache->set($key, $response, $ttl);
+		}
+	}
+
+	/**
+	 * Calculates the total Time To Live based on the specification
+	 * RFC 2616 cache lifetime rules.
+	 *
+	 * @param   Response  $response  Response to evaluate
+	 * @return  mixed  TTL value or false if the response should not be cached
+	 */
+	public function cache_lifetime(Response $response)
+	{
+		// Get out of here if this cannot be cached
+		if ( ! $this->set_cache($response))
+			return FALSE;
+
+		// Calculate apparent age
+		if ($date = $response->headers('date'))
+		{
+			$apparent_age = max(0, $this->_response_time - strtotime($date));
+		}
+		else
+		{
+			$apparent_age = max(0, $this->_response_time);
+		}
+
+		// Calculate corrected received age
+		if ($age = $response->headers('age'))
+		{
+			$corrected_received_age = max($apparent_age, intval($age));
+		}
+		else
+		{
+			$corrected_received_age = $apparent_age;
+		}
+
+		// Corrected initial age
+		$corrected_initial_age = $corrected_received_age + $this->request_execution_time();
+
+		// Resident time
+		$resident_time = time() - $this->_response_time;
+
+		// Current age
+		$current_age = $corrected_initial_age + $resident_time;
+
+		// Prepare the cache freshness lifetime
+		$ttl = NULL;
+
+		// Cache control overrides
+		if ($cache_control = $response->headers('cache-control'))
+		{
+			// Parse the cache control header
+			$cache_control = HTTP_Header::parse_cache_control($cache_control);
+
+			if (isset($cache_control['max-age']))
+			{
+				$ttl = $cache_control['max-age'];
+			}
+
+			if (isset($cache_control['s-maxage']) AND isset($cache_control['private']) AND $this->_allow_private_cache)
+			{
+				$ttl = $cache_control['s-maxage'];
+			}
+
+			if (isset($cache_control['max-stale']) AND ! isset($cache_control['must-revalidate']))
+			{
+				$ttl = $current_age + $cache_control['max-stale'];
+			}
+		}
+
+		// If we have a TTL at this point, return
+		if ($ttl !== NULL)
+			return $ttl;
+
+		if ($expires = $response->headers('expires'))
+			return strtotime($expires) - $current_age;
+
+		return FALSE;
+	}
+
+	/**
+	 * Returns the duration of the last request execution.
+	 * Either returns the time of completed requests or
+	 * `FALSE` if the request hasn't finished executing, or
+	 * is yet to be run.
+	 *
+	 * @return  mixed
+	 */
+	public function request_execution_time()
+	{
+		if ($this->_request_time === NULL OR $this->_response_time === NULL)
+			return FALSE;
+
+		return $this->_response_time - $this->_request_time;
+	}
+
+} // End Kohana_HTTP_Cache