Builds the run-time theme registry.

Extends DrupalCacheArray to allow the theme registry to be accessed as a complete registry, while internally caching only the parts of the registry that are actually in use on the site. On cache misses the complete theme registry is loaded and used to update the run-time cache.

Hierarchy

Expanded class hierarchy of ThemeRegistry

1 string reference to 'ThemeRegistry'
ThemeRegistryTestCase::getInfo in modules/simpletest/tests/theme.test

File

includes/theme.inc, line 365
The theme system, which controls the output of Drupal.

View source
class ThemeRegistry extends DrupalCacheArray {

  /**
   * Whether the partial registry can be persisted to the cache.
   *
   * This is only allowed if all modules and the request method is GET. theme()
   * should be very rarely called on POST requests and this avoids polluting
   * the runtime cache.
   */
  protected $persistable;

  /**
   * The complete theme registry array.
   */
  protected $completeRegistry;
  function __construct($cid, $bin) {
    $this->cid = $cid;
    $this->bin = $bin;
    $this->persistable = module_load_all(NULL) && $_SERVER['REQUEST_METHOD'] == 'GET';
    $data = array();
    if ($this->persistable && ($cached = cache_get($this->cid, $this->bin))) {
      $data = $cached->data;
    }
    else {

      // If there is no runtime cache stored, fetch the full theme registry,
      // but then initialize each value to NULL. This allows offsetExists()
      // to function correctly on non-registered theme hooks without triggering
      // a call to resolveCacheMiss().
      $data = $this
        ->initializeRegistry();
      if ($this->persistable) {
        $this
          ->set($data);
      }
    }
    $this->storage = $data;
  }

  /**
   * Initializes the full theme registry.
   *
   * @return
   *   An array with the keys of the full theme registry, but the values
   *   initialized to NULL.
   */
  function initializeRegistry() {
    $this->completeRegistry = theme_get_registry();
    return array_fill_keys(array_keys($this->completeRegistry), NULL);
  }
  public function offsetExists($offset) {

    // Since the theme registry allows for theme hooks to be requested that
    // are not registered, just check the existence of the key in the registry.
    // Use array_key_exists() here since a NULL value indicates that the theme
    // hook exists but has not yet been requested.
    return isset($this->storage[$offset]) || array_key_exists($offset, $this->storage);
  }
  public function offsetGet($offset) {

    // If the offset is set but empty, it is a registered theme hook that has
    // not yet been requested. Offsets that do not exist at all were not
    // registered in hook_theme().
    if (isset($this->storage[$offset])) {
      return $this->storage[$offset];
    }
    elseif (array_key_exists($offset, $this->storage)) {
      return $this
        ->resolveCacheMiss($offset);
    }
  }
  public function resolveCacheMiss($offset) {
    if (!isset($this->completeRegistry)) {
      $this->completeRegistry = theme_get_registry();
    }
    $this->storage[$offset] = $this->completeRegistry[$offset];
    if ($this->persistable) {
      $this
        ->persist($offset);
    }
    return $this->storage[$offset];
  }
  public function set($data, $lock = TRUE) {
    $lock_name = $this->cid . ':' . $this->bin;
    if (!$lock || lock_acquire($lock_name)) {
      if ($cached = cache_get($this->cid, $this->bin)) {

        // Use array merge instead of union so that filled in values in $data
        // overwrite empty values in the current cache.
        $data = array_merge($cached->data, $data);
      }
      else {
        $registry = $this
          ->initializeRegistry();
        $data = array_merge($registry, $data);
      }
      cache_set($this->cid, $data, $this->bin);
      if ($lock) {
        lock_release($lock_name);
      }
    }
  }

}

Members

Name Modifierssort descending Type Description Overrides
ThemeRegistry::__construct function Constructs a DrupalCacheArray object. Overrides DrupalCacheArray::__construct
ThemeRegistry::initializeRegistry function Initializes the full theme registry.
DrupalCacheArray::persist protected function Flags an offset value to be written to the persistent cache.
ThemeRegistry::$persistable protected property Whether the partial registry can be persisted to the cache.
ThemeRegistry::$completeRegistry protected property The complete theme registry array.
DrupalCacheArray::$cid protected property A cid to pass to cache_set() and cache_get().
DrupalCacheArray::$bin protected property A bin to pass to cache_set() and cache_get().
DrupalCacheArray::$keysToPersist protected property An array of keys to add to the cache at the end of the request.
DrupalCacheArray::$storage protected property Storage for the data itself.
ThemeRegistry::offsetExists public function Implements ArrayAccess::offsetExists(). Overrides DrupalCacheArray::offsetExists
ThemeRegistry::offsetGet public function Implements ArrayAccess::offsetGet(). Overrides DrupalCacheArray::offsetGet
ThemeRegistry::resolveCacheMiss public function Resolves a cache miss. Overrides DrupalCacheArray::resolveCacheMiss
ThemeRegistry::set public function Writes a value to the persistent cache immediately. Overrides DrupalCacheArray::set
DrupalCacheArray::offsetSet public function
DrupalCacheArray::offsetUnset public function
DrupalCacheArray::__destruct public function Destructs the DrupalCacheArray object.