/engine/lib/cache.php
PHP | 439 lines | 167 code | 68 blank | 204 comment | 19 complexity | 45b4b7723e5ef4fab08c02bc4db158b9 MD5 | raw file
- <?php
- /**
- * Elgg cache
- * Cache file interface for caching data.
- *
- * @package Elgg
- * @subpackage API
- * @license http://www.gnu.org/licenses/old-licenses/gpl-2.0.html GNU Public License version 2
- * @author Curverider Ltd <info@elgg.com>
- * @copyright Curverider Ltd 2008-2009
- * @link http://elgg.org/
- */
- /**
- * ElggCache The elgg cache superclass.
- * This defines the interface for a cache (wherever that cache is stored).
- *
- * @author Curverider Ltd <info@elgg.com>
- * @package Elgg
- * @subpackage API
- */
- abstract class ElggCache implements
- ArrayAccess // Override for array access
- {
- /**
- * Variables for the cache object.
- *
- * @var array
- */
- private $variables;
-
- /**
- * Set the constructor.
- */
- function __construct() { $this->variables = array(); }
-
- /**
- * Set a cache variable.
- *
- * @param string $variable
- * @param string $value
- */
- public function set_variable($variable, $value)
- {
- if (!is_array($this->variables))
- $this->variables = array();
-
- $this->variables[$variable] = $value;
- }
-
- /**
- * Get variables for this cache.
- *
- * @param string $variable
- * @return mixed The variable or null;
- */
- public function get_variable($variable)
- {
- if (isset($this->variables[$variable]))
- return $this->variables[$variable];
-
- return null;
- }
-
- /**
- * Class member get overloading, returning key using $this->load defaults.
- *
- * @param string $key
- * @return mixed
- */
- function __get($key) { return $this->load($key); }
-
- /**
- * Class member set overloading, setting a key using $this->save defaults.
- *
- * @param string $key
- * @param mixed $value
- * @return mixed
- */
- function __set($key, $value) { return $this->save($key, $value); }
-
- /**
- * Supporting isset, using $this->load() with default values.
- *
- * @param string $key The name of the attribute or metadata.
- * @return bool
- */
- function __isset($key) { return (bool)$this->load($key); }
-
- /**
- * Supporting unsetting of magic attributes.
- *
- * @param string $key The name of the attribute or metadata.
- */
- function __unset($key) { return $this->delete($key); }
-
- /**
- * Save data in a cache.
- *
- * @param string $key
- * @param string $data
- * @return bool
- */
- abstract public function save($key, $data);
-
- /**
- * Load data from the cache using a given key.
- *
- * @param string $key
- * @param int $offset
- * @param int $limit
- * @return mixed The stored data or false.
- */
- abstract public function load($key, $offset = 0, $limit = null);
-
- /**
- * Invalidate a key
- *
- * @param string $key
- * @return bool
- */
- abstract public function delete($key);
-
- /**
- * Clear out all the contents of the cache.
- *
- */
- abstract public function clear();
-
- /**
- * Add a key only if it doesn't already exist.
- * Implemented simply here, if you extend this class and your caching engine provides a better way then
- * override this accordingly.
- *
- * @param string $key
- * @param string $data
- * @return bool
- */
- public function add($key, $data)
- {
- if (!isset($this[$key]))
- return $this->save($key, $data);
-
- return false;
- }
-
- // ARRAY ACCESS INTERFACE //////////////////////////////////////////////////////////
- function offsetSet($key, $value)
- {
- $this->save($key, $value);
- }
-
- function offsetGet($key)
- {
- return $this->load($key);
- }
-
- function offsetUnset($key)
- {
- if ( isset($this->key) ) {
- unset($this->key);
- }
- }
-
- function offsetExists($offset)
- {
- return isset($this->$offset);
- }
- }
-
- /**
- * Shared memory cache description.
- * Extends ElggCache with functions useful to shared memory style caches (static variables, memcache etc)
- */
- abstract class ElggSharedMemoryCache extends ElggCache
- {
- /**
- * Namespace variable used to keep various bits of the cache
- * separate.
- *
- * @var string
- */
- private $namespace;
-
- /**
- * Set the namespace of this cache.
- * This is useful for cache types (like memcache or static variables) where there is one large
- * flat area of memory shared across all instances of the cache.
- *
- * @param string $namespace
- */
- public function setNamespace($namespace = "default") { $this->namespace = $namespace; }
- /**
- * Get the namespace currently defined.
- *
- * @return string
- */
- public function getNamespace() { return $this->namespace; }
- }
-
- /**
- * ElggStaticVariableCache
- * Dummy cache which stores values in a static array. Using this makes future replacements to other caching back
- * ends (eg memcache) much easier.
- *
- * @author Curverider Ltd <info@elgg.com>
- * @package Elgg
- * @subpackage API
- */
- class ElggStaticVariableCache extends ElggSharedMemoryCache
- {
- /**
- * The cache.
- *
- * @var unknown_type
- */
- private static $__cache;
-
- /**
- * Create the variable cache.
- *
- * This function creates a variable cache in a static variable in memory, optionally with a given namespace (to avoid overlap).
- *
- * @param string $namespace The namespace for this cache to write to - note, namespaces of the same name are shared!
- */
- function __construct($namespace = 'default')
- {
- $this->setNamespace($namespace);
- $this->clear();
- }
-
- public function save($key, $data)
- {
- $namespace = $this->getNamespace();
-
- ElggStaticVariableCache::$__cache[$namespace][$key] = $data;
-
- return true;
- }
-
- public function load($key, $offset = 0, $limit = null)
- {
- $namespace = $this->getNamespace();
-
- if (isset(ElggStaticVariableCache::$__cache[$namespace][$key]))
- return ElggStaticVariableCache::$__cache[$namespace][$key];
-
- return false;
- }
-
- public function delete($key)
- {
- $namespace = $this->getNamespace();
-
- unset(ElggStaticVariableCache::$__cache[$namespace][$key]);
-
- return true;
- }
-
- public function clear()
- {
- $namespace = $this->getNamespace();
-
- if (!isset(ElggStaticVariableCache::$__cache))
- ElggStaticVariableCache::$__cache = array();
-
- //if (!isset(ElggStaticVariableCache::$__cache[$namespace]))
- ElggStaticVariableCache::$__cache[$namespace] = array();
- }
- }
-
- /**
- * ElggFileCache
- * Store cached data in a file store.
- *
- * @author Curverider Ltd <info@elgg.com>
- * @package Elgg
- * @subpackage API
- */
- class ElggFileCache extends ElggCache
- {
- /**
- * Set the Elgg cache.
- *
- * @param string $cache_path The cache path.
- * @param int $max_age Maximum age in seconds, 0 if no limit.
- * @param int $max_size Maximum size of cache in seconds, 0 if no limit.
- */
- function __construct($cache_path, $max_age = 0, $max_size = 0)
- {
- $this->set_variable("cache_path", $cache_path);
- $this->set_variable("max_age", $max_age);
- $this->set_variable("max_size", $max_size);
- if ($cache_path=="") throw new ConfigurationException(elgg_echo('ConfigurationException:NoCachePath'));
- }
-
- /**
- * Create and return a handle to a file.
- *
- * @param string $filename
- * @param string $rw
- */
- protected function create_file($filename, $rw = "rb")
- {
- // Create a filename matrix
- $matrix = "";
- $depth = strlen($filename);
- if ($depth > 5) $depth = 5;
-
- // for ($n = 0; $n < $depth; $n++)
- // $matrix .= $filename[$n] . "/";
-
- // Create full path
- $path = $this->get_variable("cache_path") . $matrix;
-
- // if (!mkdir($path, 0700, true)) throw new IOException("Could not make $path");
-
- // Open the file
- if ((!file_exists($path . $filename)) && ($rw=="rb")) return false;
-
- return fopen($path . $filename, $rw);
- }
-
- /**
- * Create a sanitised filename for the file.
- *
- * @param string $filename
- */
- protected function sanitise_filename($filename)
- {
- // TODO : Writeme
- return $filename;
- }
-
- /**
- * Save a key
- *
- * @param string $key
- * @param string $data
- * @return boolean
- */
- public function save($key, $data)
- {
- $f = $this->create_file($this->sanitise_filename($key), "wb");
- if ($f)
- {
- $result = fwrite($f, $data);
- fclose($f);
-
- return $result;
- }
-
- return false;
- }
-
- /**
- * Load a key
- *
- * @param string $key
- * @param int $offset
- * @param int $limit
- * @return string
- */
- public function load($key, $offset = 0, $limit = null)
- {
- $f = $this->create_file($this->sanitise_filename($key));
- if ($f)
- {
- //fseek($f, $offset);
- if (!$limit) $limit = -1;
- $data = stream_get_contents($f, $limit, $offset);
-
- fclose($f);
-
- return $data;
- }
-
- return false;
- }
-
- /**
- * Invalidate a given key.
- *
- * @param string $key
- * @return bool
- */
- public function delete($key)
- {
- $dir = $this->get_variable("cache_path");
-
- return unlink($dir.$key);
- }
-
- public function clear()
- {
- // TODO : writeme
- }
-
- public function __destruct()
- {
- // TODO: Check size and age, clean up accordingly
- $size = 0;
- $dir = $this->get_variable("cache_path");
-
- // Short circuit if both size and age are unlimited
- if (($this->get_variable("max_age")==0) && ($this->get_variable("max_size")==0))
- return;
-
- $exclude = array(".","..");
-
- $files = scandir($dir);
- if (!$files) throw new IOException(sprintf(elgg_echo('IOException:NotDirectory'), $dir));
-
- // Perform cleanup
- foreach ($files as $f)
- {
- if (!in_array($f, $exclude))
- {
- $stat = stat($dir.$f);
-
- // Add size
- $size .= $stat['size'];
-
- // Is this older than my maximum date?
- if (($this->get_variable("max_age")>0) && (time() - $stat['mtime'] > $this->get_variable("max_age")))
- unlink($dir.$f);
-
-
-
- // TODO: Size
-
- }
- }
- }
- }
-
- ?>