Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\Core\Theme;
Chris@0: 
Chris@14: use Drupal\Component\Utility\NestedArray;
Chris@0: use Drupal\Core\Cache\Cache;
Chris@0: use Drupal\Core\Cache\CacheBackendInterface;
Chris@0: use Drupal\Core\DestructableInterface;
Chris@0: use Drupal\Core\Extension\ModuleHandlerInterface;
Chris@0: use Drupal\Core\Extension\ThemeHandlerInterface;
Chris@0: use Drupal\Core\Lock\LockBackendInterface;
Chris@0: use Drupal\Core\Utility\ThemeRegistry;
Chris@0: 
Chris@0: /**
Chris@0:  * Defines the theme registry service.
Chris@0:  *
Chris@0:  * @internal
Chris@0:  *
Chris@0:  * Theme registry is expected to be used only internally since every
Chris@0:  * hook_theme() implementation depends on the way this class is built. This
Chris@0:  * class may get new features in minor releases so this class should be
Chris@0:  * considered internal.
Chris@0:  *
Chris@0:  * @todo Replace local $registry variables in methods with $this->registry.
Chris@0:  */
Chris@0: class Registry implements DestructableInterface {
Chris@0: 
Chris@0:   /**
Chris@0:    * The theme object representing the active theme for this registry.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Theme\ActiveTheme
Chris@0:    */
Chris@0:   protected $theme;
Chris@0: 
Chris@0:   /**
Chris@0:    * The lock backend that should be used.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Lock\LockBackendInterface
Chris@0:    */
Chris@0:   protected $lock;
Chris@0: 
Chris@0:   /**
Chris@0:    * The complete theme registry.
Chris@0:    *
Chris@0:    * @var array
Chris@0:    *   An array of theme registries, keyed by the theme name. Each registry is
Chris@0:    *   an associative array keyed by theme hook names, whose values are
Chris@0:    *   associative arrays containing the aggregated hook definition:
Chris@0:    *   - type: The type of the extension the original theme hook originates
Chris@0:    *     from; e.g., 'module' for theme hook 'node' of Node module.
Chris@0:    *   - name: The name of the extension the original theme hook originates
Chris@0:    *     from; e.g., 'node' for theme hook 'node' of Node module.
Chris@0:    *   - theme path: The effective \Drupal\Core\Theme\ActiveTheme::getPath()
Chris@0:    *      during \Drupal\Core\Theme\ThemeManagerInterface::render(), available
Chris@0:    *      as 'directory' variable in templates. For functions, it should point
Chris@0:    *      to the respective theme. For templates, it should point to the
Chris@0:    *      directory that contains the template.
Chris@0:    *   - includes: (optional) An array of include files to load when the theme
Chris@0:    *     hook is executed by \Drupal\Core\Theme\ThemeManagerInterface::render().
Chris@0:    *   - file: (optional) A filename to add to 'includes', either prefixed with
Chris@0:    *     the value of 'path', or the path of the extension implementing
Chris@0:    *     hook_theme().
Chris@0:    *   In case of a theme base hook, one of the following:
Chris@0:    *   - variables: An associative array whose keys are variable names and whose
Chris@0:    *     values are default values of the variables to use for this theme hook.
Chris@0:    *   - render element: A string denoting the name of the variable name, in
Chris@0:    *     which the render element for this theme hook is provided.
Chris@0:    *   In case of a theme template file:
Chris@0:    *   - path: The path to the template file to use. Defaults to the
Chris@0:    *     subdirectory 'templates' of the path of the extension implementing
Chris@0:    *     hook_theme(); e.g., 'core/modules/node/templates' for Node module.
Chris@0:    *   - template: The basename of the template file to use, without extension
Chris@0:    *     (as the extension is specific to the theme engine). The template file
Chris@0:    *     is in the directory defined by 'path'.
Chris@0:    *   - template_file: A full path and file name to a template file to use.
Chris@0:    *     Allows any extension to override the effective template file.
Chris@0:    *   - engine: The theme engine to use for the template file.
Chris@0:    *   In case of a theme function:
Chris@0:    *   - function: The function name to call to generate the output.
Chris@0:    *   For any registered theme hook, including theme hook suggestions:
Chris@0:    *   - preprocess: An array of theme variable preprocess callbacks to invoke
Chris@0:    *     before invoking final theme variable processors.
Chris@0:    *   - process: An array of theme variable process callbacks to invoke
Chris@0:    *     before invoking the actual theme function or template.
Chris@0:    */
Chris@0:   protected $registry = [];
Chris@0: 
Chris@0:   /**
Chris@0:    * The cache backend to use for the complete theme registry data.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Cache\CacheBackendInterface
Chris@0:    */
Chris@0:   protected $cache;
Chris@0: 
Chris@0:   /**
Chris@0:    * The module handler to use to load modules.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Extension\ModuleHandlerInterface
Chris@0:    */
Chris@0:   protected $moduleHandler;
Chris@0: 
Chris@0:   /**
Chris@0:    * An array of incomplete, runtime theme registries, keyed by theme name.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Utility\ThemeRegistry[]
Chris@0:    */
Chris@0:   protected $runtimeRegistry = [];
Chris@0: 
Chris@0:   /**
Chris@0:    * Stores whether the registry was already initialized.
Chris@0:    *
Chris@0:    * @var bool
Chris@0:    */
Chris@0:   protected $initialized = FALSE;
Chris@0: 
Chris@0:   /**
Chris@0:    * The name of the theme for which to construct the registry, if given.
Chris@0:    *
Chris@0:    * @var string|null
Chris@0:    */
Chris@0:   protected $themeName;
Chris@0: 
Chris@0:   /**
Chris@0:    * The app root.
Chris@0:    *
Chris@0:    * @var string
Chris@0:    */
Chris@0:   protected $root;
Chris@0: 
Chris@0:   /**
Chris@0:    * The theme handler.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Extension\ThemeHandlerInterface
Chris@0:    */
Chris@0:   protected $themeHandler;
Chris@0: 
Chris@0:   /**
Chris@0:    * The theme manager.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Theme\ThemeManagerInterface
Chris@0:    */
Chris@0:   protected $themeManager;
Chris@0: 
Chris@0:   /**
Chris@0:    * The runtime cache.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Cache\CacheBackendInterface
Chris@0:    */
Chris@0:   protected $runtimeCache;
Chris@0: 
Chris@0:   /**
Chris@0:    * Constructs a \Drupal\Core\Theme\Registry object.
Chris@0:    *
Chris@0:    * @param string $root
Chris@0:    *   The app root.
Chris@0:    * @param \Drupal\Core\Cache\CacheBackendInterface $cache
Chris@0:    *   The cache backend interface to use for the complete theme registry data.
Chris@0:    * @param \Drupal\Core\Lock\LockBackendInterface $lock
Chris@0:    *   The lock backend.
Chris@0:    * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
Chris@0:    *   The module handler to use to load modules.
Chris@0:    * @param \Drupal\Core\Extension\ThemeHandlerInterface $theme_handler
Chris@0:    *   The theme handler.
Chris@0:    * @param \Drupal\Core\Theme\ThemeInitializationInterface $theme_initialization
Chris@0:    *   The theme initialization.
Chris@0:    * @param string $theme_name
Chris@0:    *   (optional) The name of the theme for which to construct the registry.
Chris@0:    * @param \Drupal\Core\Cache\CacheBackendInterface $runtime_cache
Chris@0:    *   The cache backend interface to use for the runtime theme registry data.
Chris@0:    */
Chris@0:   public function __construct($root, CacheBackendInterface $cache, LockBackendInterface $lock, ModuleHandlerInterface $module_handler, ThemeHandlerInterface $theme_handler, ThemeInitializationInterface $theme_initialization, $theme_name = NULL, CacheBackendInterface $runtime_cache = NULL) {
Chris@0:     $this->root = $root;
Chris@0:     $this->cache = $cache;
Chris@0:     $this->lock = $lock;
Chris@0:     $this->moduleHandler = $module_handler;
Chris@0:     $this->themeName = $theme_name;
Chris@0:     $this->themeHandler = $theme_handler;
Chris@0:     $this->themeInitialization = $theme_initialization;
Chris@0:     $this->runtimeCache = $runtime_cache;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Sets the theme manager.
Chris@0:    *
Chris@0:    * @param \Drupal\Core\Theme\ThemeManagerInterface $theme_manager
Chris@0:    *   The theme manager.
Chris@0:    */
Chris@0:   public function setThemeManager(ThemeManagerInterface $theme_manager) {
Chris@0:     $this->themeManager = $theme_manager;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Initializes a theme with a certain name.
Chris@0:    *
Chris@0:    * This function does to much magic, so it should be replaced by another
Chris@0:    * services which holds the current active theme information.
Chris@0:    *
Chris@0:    * @param string $theme_name
Chris@0:    *   (optional) The name of the theme for which to construct the registry.
Chris@0:    */
Chris@0:   protected function init($theme_name = NULL) {
Chris@0:     if ($this->initialized) {
Chris@0:       return;
Chris@0:     }
Chris@0:     // Unless instantiated for a specific theme, use globals.
Chris@0:     if (!isset($theme_name)) {
Chris@0:       $this->theme = $this->themeManager->getActiveTheme();
Chris@0:     }
Chris@0:     // Instead of the active theme, a specific theme was requested.
Chris@0:     else {
Chris@0:       $this->theme = $this->themeInitialization->getActiveThemeByName($theme_name);
Chris@0:       $this->themeInitialization->loadActiveTheme($this->theme);
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Returns the complete theme registry from cache or rebuilds it.
Chris@0:    *
Chris@0:    * @return array
Chris@0:    *   The complete theme registry data array.
Chris@0:    *
Chris@0:    * @see Registry::$registry
Chris@0:    */
Chris@0:   public function get() {
Chris@0:     $this->init($this->themeName);
Chris@0:     if (isset($this->registry[$this->theme->getName()])) {
Chris@0:       return $this->registry[$this->theme->getName()];
Chris@0:     }
Chris@0:     if ($cache = $this->cache->get('theme_registry:' . $this->theme->getName())) {
Chris@0:       $this->registry[$this->theme->getName()] = $cache->data;
Chris@0:     }
Chris@0:     else {
Chris@0:       $this->build();
Chris@0:       // Only persist it if all modules are loaded to ensure it is complete.
Chris@0:       if ($this->moduleHandler->isLoaded()) {
Chris@0:         $this->setCache();
Chris@0:       }
Chris@0:     }
Chris@0:     return $this->registry[$this->theme->getName()];
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Returns the incomplete, runtime theme registry.
Chris@0:    *
Chris@0:    * @return \Drupal\Core\Utility\ThemeRegistry
Chris@0:    *   A shared instance of the ThemeRegistry class, provides an ArrayObject
Chris@0:    *   that allows it to be accessed with array syntax and isset(), and is more
Chris@0:    *   lightweight than the full registry.
Chris@0:    */
Chris@0:   public function getRuntime() {
Chris@0:     $this->init($this->themeName);
Chris@0:     if (!isset($this->runtimeRegistry[$this->theme->getName()])) {
Chris@0:       $this->runtimeRegistry[$this->theme->getName()] = new ThemeRegistry('theme_registry:runtime:' . $this->theme->getName(), $this->runtimeCache ?: $this->cache, $this->lock, ['theme_registry'], $this->moduleHandler->isLoaded());
Chris@0:     }
Chris@0:     return $this->runtimeRegistry[$this->theme->getName()];
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Persists the theme registry in the cache backend.
Chris@0:    */
Chris@0:   protected function setCache() {
Chris@0:     $this->cache->set('theme_registry:' . $this->theme->getName(), $this->registry[$this->theme->getName()], Cache::PERMANENT, ['theme_registry']);
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Returns the base hook for a given hook suggestion.
Chris@0:    *
Chris@0:    * @param string $hook
Chris@0:    *   The name of a theme hook whose base hook to find.
Chris@0:    *
Chris@0:    * @return string|false
Chris@0:    *   The name of the base hook or FALSE.
Chris@0:    */
Chris@0:   public function getBaseHook($hook) {
Chris@0:     $this->init($this->themeName);
Chris@0:     $base_hook = $hook;
Chris@0:     // Iteratively strip everything after the last '__' delimiter, until a
Chris@0:     // base hook definition is found. Recursive base hooks of base hooks are
Chris@0:     // not supported, so the base hook must be an original implementation that
Chris@0:     // points to a theme function or template.
Chris@0:     while ($pos = strrpos($base_hook, '__')) {
Chris@0:       $base_hook = substr($base_hook, 0, $pos);
Chris@0:       if (isset($this->registry[$base_hook]['exists'])) {
Chris@0:         break;
Chris@0:       }
Chris@0:     }
Chris@0:     if ($pos !== FALSE && $base_hook !== $hook) {
Chris@0:       return $base_hook;
Chris@0:     }
Chris@0:     return FALSE;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Builds the theme registry cache.
Chris@0:    *
Chris@0:    * Theme hook definitions are collected in the following order:
Chris@0:    * - Modules
Chris@0:    * - Base theme engines
Chris@0:    * - Base themes
Chris@0:    * - Theme engine
Chris@0:    * - Theme
Chris@0:    *
Chris@0:    * All theme hook definitions are essentially just collated and merged in the
Chris@0:    * above order. However, various extension-specific default values and
Chris@0:    * customizations are required; e.g., to record the effective file path for
Chris@0:    * theme template. Therefore, this method first collects all extensions per
Chris@0:    * type, and then dispatches the processing for each extension to
Chris@0:    * processExtension().
Chris@0:    *
Chris@0:    * After completing the collection, modules are allowed to alter it. Lastly,
Chris@0:    * any derived and incomplete theme hook definitions that are hook suggestions
Chris@0:    * for base hooks (e.g., 'block__node' for the base hook 'block') need to be
Chris@0:    * determined based on the full registry and classified as 'base hook'.
Chris@0:    *
Chris@0:    * See the @link themeable Default theme implementations topic @endlink for
Chris@0:    * details.
Chris@0:    *
Chris@0:    * @return \Drupal\Core\Utility\ThemeRegistry
Chris@0:    *   The build theme registry.
Chris@0:    *
Chris@0:    * @see hook_theme_registry_alter()
Chris@0:    */
Chris@0:   protected function build() {
Chris@0:     $cache = [];
Chris@0:     // First, preprocess the theme hooks advertised by modules. This will
Chris@0:     // serve as the basic registry. Since the list of enabled modules is the
Chris@0:     // same regardless of the theme used, this is cached in its own entry to
Chris@0:     // save building it for every theme.
Chris@0:     if ($cached = $this->cache->get('theme_registry:build:modules')) {
Chris@0:       $cache = $cached->data;
Chris@0:     }
Chris@0:     else {
Chris@0:       foreach ($this->moduleHandler->getImplementations('theme') as $module) {
Chris@0:         $this->processExtension($cache, $module, 'module', $module, $this->getPath($module));
Chris@0:       }
Chris@0:       // Only cache this registry if all modules are loaded.
Chris@0:       if ($this->moduleHandler->isLoaded()) {
Chris@0:         $this->cache->set("theme_registry:build:modules", $cache, Cache::PERMANENT, ['theme_registry']);
Chris@0:       }
Chris@0:     }
Chris@0: 
Chris@0:     // Process each base theme.
Chris@0:     // Ensure that we start with the root of the parents, so that both CSS files
Chris@0:     // and preprocess functions comes first.
Chris@18:     foreach (array_reverse($this->theme->getBaseThemeExtensions()) as $base) {
Chris@0:       // If the base theme uses a theme engine, process its hooks.
Chris@0:       $base_path = $base->getPath();
Chris@0:       if ($this->theme->getEngine()) {
Chris@0:         $this->processExtension($cache, $this->theme->getEngine(), 'base_theme_engine', $base->getName(), $base_path);
Chris@0:       }
Chris@0:       $this->processExtension($cache, $base->getName(), 'base_theme', $base->getName(), $base_path);
Chris@0:     }
Chris@0: 
Chris@0:     // And then the same thing, but for the theme.
Chris@0:     if ($this->theme->getEngine()) {
Chris@0:       $this->processExtension($cache, $this->theme->getEngine(), 'theme_engine', $this->theme->getName(), $this->theme->getPath());
Chris@0:     }
Chris@0: 
Chris@0:     // Hooks provided by the theme itself.
Chris@0:     $this->processExtension($cache, $this->theme->getName(), 'theme', $this->theme->getName(), $this->theme->getPath());
Chris@0: 
Chris@0:     // Discover and add all preprocess functions for theme hook suggestions.
Chris@0:     $this->postProcessExtension($cache, $this->theme);
Chris@0: 
Chris@0:     // Let modules and themes alter the registry.
Chris@0:     $this->moduleHandler->alter('theme_registry', $cache);
Chris@0:     $this->themeManager->alterForTheme($this->theme, 'theme_registry', $cache);
Chris@0: 
Chris@0:     // @todo Implement more reduction of the theme registry entry.
Chris@0:     // Optimize the registry to not have empty arrays for functions.
Chris@0:     foreach ($cache as $hook => $info) {
Chris@0:       if (empty($info['preprocess functions'])) {
Chris@0:         unset($cache[$hook]['preprocess functions']);
Chris@0:       }
Chris@0:     }
Chris@0:     $this->registry[$this->theme->getName()] = $cache;
Chris@0: 
Chris@0:     return $this->registry[$this->theme->getName()];
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Process a single implementation of hook_theme().
Chris@0:    *
Chris@0:    * @param array $cache
Chris@0:    *   The theme registry that will eventually be cached; It is an associative
Chris@0:    *   array keyed by theme hooks, whose values are associative arrays
Chris@0:    *   describing the hook:
Chris@0:    *   - 'type': The passed-in $type.
Chris@0:    *   - 'theme path': The passed-in $path.
Chris@0:    *   - 'function': The name of the function generating output for this theme
Chris@0:    *     hook. Either defined explicitly in hook_theme() or, if neither
Chris@0:    *     'function' nor 'template' is defined, then the default theme function
Chris@0:    *     name is used. The default theme function name is the theme hook
Chris@0:    *     prefixed by either 'theme_' for modules or '$name_' for everything
Chris@0:    *     else. If 'function' is defined, 'template' is not used.
Chris@0:    *   - 'template': The filename of the template generating output for this
Chris@0:    *     theme hook. The template is in the directory defined by the 'path' key
Chris@0:    *     of hook_theme() or defaults to "$path/templates".
Chris@0:    *   - 'variables': The variables for this theme hook as defined in
Chris@0:    *     hook_theme(). If there is more than one implementation and 'variables'
Chris@0:    *     is not specified in a later one, then the previous definition is kept.
Chris@0:    *   - 'render element': The renderable element for this theme hook as defined
Chris@0:    *     in hook_theme(). If there is more than one implementation and
Chris@0:    *     'render element' is not specified in a later one, then the previous
Chris@0:    *     definition is kept.
Chris@0:    *   - See the @link themeable Theme system overview topic @endlink for
Chris@0:    *     detailed documentation.
Chris@0:    * @param string $name
Chris@0:    *   The name of the module, theme engine, base theme engine, theme or base
Chris@0:    *   theme implementing hook_theme().
Chris@0:    * @param string $type
Chris@0:    *   One of 'module', 'theme_engine', 'base_theme_engine', 'theme', or
Chris@0:    *   'base_theme'. Unlike regular hooks that can only be implemented by
Chris@0:    *   modules, each of these can implement hook_theme(). This function is
Chris@0:    *   called in aforementioned order and new entries override older ones. For
Chris@0:    *   example, if a theme hook is both defined by a module and a theme, then
Chris@0:    *   the definition in the theme will be used.
Chris@0:    * @param string $theme
Chris@0:    *   The actual name of theme, module, etc. that is being processed.
Chris@0:    * @param string $path
Chris@0:    *   The directory where $name is. For example, modules/system or
Chris@0:    *   themes/bartik.
Chris@0:    *
Chris@0:    * @see \Drupal\Core\Theme\ThemeManagerInterface::render()
Chris@0:    * @see hook_theme()
Chris@0:    * @see \Drupal\Core\Extension\ThemeHandler::listInfo()
Chris@0:    * @see twig_render_template()
Chris@0:    *
Chris@0:    * @throws \BadFunctionCallException
Chris@0:    */
Chris@0:   protected function processExtension(array &$cache, $name, $type, $theme, $path) {
Chris@0:     $result = [];
Chris@0: 
Chris@0:     $hook_defaults = [
Chris@0:       'variables' => TRUE,
Chris@0:       'render element' => TRUE,
Chris@0:       'pattern' => TRUE,
Chris@0:       'base hook' => TRUE,
Chris@0:     ];
Chris@0: 
Chris@0:     $module_list = array_keys($this->moduleHandler->getModuleList());
Chris@0: 
Chris@0:     // Invoke the hook_theme() implementation, preprocess what is returned, and
Chris@0:     // merge it into $cache.
Chris@0:     $function = $name . '_theme';
Chris@0:     if (function_exists($function)) {
Chris@0:       $result = $function($cache, $type, $theme, $path);
Chris@0:       foreach ($result as $hook => $info) {
Chris@0:         // When a theme or engine overrides a module's theme function
Chris@0:         // $result[$hook] will only contain key/value pairs for information being
Chris@0:         // overridden.  Pull the rest of the information from what was defined by
Chris@0:         // an earlier hook.
Chris@0: 
Chris@0:         // Fill in the type and path of the module, theme, or engine that
Chris@0:         // implements this theme function.
Chris@0:         $result[$hook]['type'] = $type;
Chris@0:         $result[$hook]['theme path'] = $path;
Chris@0: 
Chris@0:         // If a theme hook has a base hook, mark its preprocess functions always
Chris@0:         // incomplete in order to inherit the base hook's preprocess functions.
Chris@0:         if (!empty($result[$hook]['base hook'])) {
Chris@0:           $result[$hook]['incomplete preprocess functions'] = TRUE;
Chris@0:         }
Chris@0: 
Chris@0:         if (isset($cache[$hook]['includes'])) {
Chris@0:           $result[$hook]['includes'] = $cache[$hook]['includes'];
Chris@0:         }
Chris@0: 
Chris@0:         // Load the includes, as they may contain preprocess functions.
Chris@0:         if (isset($info['includes'])) {
Chris@0:           foreach ($info['includes'] as $include_file) {
Chris@0:             include_once $this->root . '/' . $include_file;
Chris@0:           }
Chris@0:         }
Chris@0: 
Chris@0:         // If the theme implementation defines a file, then also use the path
Chris@0:         // that it defined. Otherwise use the default path. This allows
Chris@0:         // system.module to declare theme functions on behalf of core .include
Chris@0:         // files.
Chris@0:         if (isset($info['file'])) {
Chris@0:           $include_file = isset($info['path']) ? $info['path'] : $path;
Chris@0:           $include_file .= '/' . $info['file'];
Chris@0:           include_once $this->root . '/' . $include_file;
Chris@0:           $result[$hook]['includes'][] = $include_file;
Chris@0:         }
Chris@0: 
Chris@0:         // A template file is the default implementation for a theme hook, but
Chris@0:         // if the theme hook specifies a function callback instead, check to
Chris@0:         // ensure the function actually exists.
Chris@0:         if (isset($info['function'])) {
Chris@0:           if (!function_exists($info['function'])) {
Chris@0:             throw new \BadFunctionCallException(sprintf(
Chris@0:               'Theme hook "%s" refers to a theme function callback that does not exist: "%s"',
Chris@0:               $hook,
Chris@0:               $info['function']
Chris@0:             ));
Chris@0:           }
Chris@0:         }
Chris@0:         // Provide a default naming convention for 'template' based on the
Chris@0:         // hook used. If the template does not exist, the theme engine used
Chris@0:         // should throw an exception at runtime when attempting to include
Chris@0:         // the template file.
Chris@0:         elseif (!isset($info['template'])) {
Chris@0:           $info['template'] = strtr($hook, '_', '-');
Chris@0:           $result[$hook]['template'] = $info['template'];
Chris@0:         }
Chris@0: 
Chris@0:         // Prepend the current theming path when none is set. This is required
Chris@0:         // for the default theme engine to know where the template lives.
Chris@0:         if (isset($result[$hook]['template']) && !isset($info['path'])) {
Chris@0:           $result[$hook]['path'] = $path . '/templates';
Chris@0:         }
Chris@0: 
Chris@0:         // If the default keys are not set, use the default values registered
Chris@0:         // by the module.
Chris@0:         if (isset($cache[$hook])) {
Chris@0:           $result[$hook] += array_intersect_key($cache[$hook], $hook_defaults);
Chris@0:         }
Chris@0: 
Chris@0:         // Preprocess variables for all theming hooks, whether the hook is
Chris@0:         // implemented as a template or as a function. Ensure they are arrays.
Chris@0:         if (!isset($info['preprocess functions']) || !is_array($info['preprocess functions'])) {
Chris@0:           $info['preprocess functions'] = [];
Chris@0:           $prefixes = [];
Chris@0:           if ($type == 'module') {
Chris@0:             // Default variable preprocessor prefix.
Chris@0:             $prefixes[] = 'template';
Chris@0:             // Add all modules so they can intervene with their own variable
Chris@0:             // preprocessors. This allows them to provide variable preprocessors
Chris@0:             // even if they are not the owner of the current hook.
Chris@0:             $prefixes = array_merge($prefixes, $module_list);
Chris@0:           }
Chris@0:           elseif ($type == 'theme_engine' || $type == 'base_theme_engine') {
Chris@0:             // Theme engines get an extra set that come before the normally
Chris@0:             // named variable preprocessors.
Chris@0:             $prefixes[] = $name . '_engine';
Chris@0:             // The theme engine registers on behalf of the theme using the
Chris@0:             // theme's name.
Chris@0:             $prefixes[] = $theme;
Chris@0:           }
Chris@0:           else {
Chris@0:             // This applies when the theme manually registers their own variable
Chris@0:             // preprocessors.
Chris@0:             $prefixes[] = $name;
Chris@0:           }
Chris@0:           foreach ($prefixes as $prefix) {
Chris@0:             // Only use non-hook-specific variable preprocessors for theming
Chris@0:             // hooks implemented as templates. See the @defgroup themeable
Chris@0:             // topic.
Chris@0:             if (isset($info['template']) && function_exists($prefix . '_preprocess')) {
Chris@0:               $info['preprocess functions'][] = $prefix . '_preprocess';
Chris@0:             }
Chris@0:             if (function_exists($prefix . '_preprocess_' . $hook)) {
Chris@0:               $info['preprocess functions'][] = $prefix . '_preprocess_' . $hook;
Chris@0:             }
Chris@0:           }
Chris@0:         }
Chris@0:         // Check for the override flag and prevent the cached variable
Chris@0:         // preprocessors from being used. This allows themes or theme engines
Chris@0:         // to remove variable preprocessors set earlier in the registry build.
Chris@0:         if (!empty($info['override preprocess functions'])) {
Chris@0:           // Flag not needed inside the registry.
Chris@0:           unset($result[$hook]['override preprocess functions']);
Chris@0:         }
Chris@0:         elseif (isset($cache[$hook]['preprocess functions']) && is_array($cache[$hook]['preprocess functions'])) {
Chris@0:           $info['preprocess functions'] = array_merge($cache[$hook]['preprocess functions'], $info['preprocess functions']);
Chris@0:         }
Chris@0:         $result[$hook]['preprocess functions'] = $info['preprocess functions'];
Chris@14: 
Chris@14:         // If a theme implementation definition provides both 'template' and
Chris@14:         // 'function', the 'function' will be used. In this case, if the new
Chris@14:         // result provides a 'template' value, any existing 'function' value
Chris@14:         // must be removed for the override to be called.
Chris@14:         if (isset($result[$hook]['template'])) {
Chris@14:           unset($cache[$hook]['function']);
Chris@14:         }
Chris@0:       }
Chris@0: 
Chris@0:       // Merge the newly created theme hooks into the existing cache.
Chris@14:       $cache = NestedArray::mergeDeep($cache, $result);
Chris@0:     }
Chris@0: 
Chris@0:     // Let themes have variable preprocessors even if they didn't register a
Chris@0:     // template.
Chris@0:     if ($type == 'theme' || $type == 'base_theme') {
Chris@0:       foreach ($cache as $hook => $info) {
Chris@0:         // Check only if not registered by the theme or engine.
Chris@0:         if (empty($result[$hook])) {
Chris@0:           if (!isset($info['preprocess functions'])) {
Chris@0:             $cache[$hook]['preprocess functions'] = [];
Chris@0:           }
Chris@0:           // Only use non-hook-specific variable preprocessors for theme hooks
Chris@0:           // implemented as templates. See the @defgroup themeable topic.
Chris@0:           if (isset($info['template']) && function_exists($name . '_preprocess')) {
Chris@0:             $cache[$hook]['preprocess functions'][] = $name . '_preprocess';
Chris@0:           }
Chris@0:           if (function_exists($name . '_preprocess_' . $hook)) {
Chris@0:             $cache[$hook]['preprocess functions'][] = $name . '_preprocess_' . $hook;
Chris@0:             $cache[$hook]['theme path'] = $path;
Chris@0:           }
Chris@0:         }
Chris@0:       }
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Completes the definition of the requested suggestion hook.
Chris@0:    *
Chris@0:    * @param string $hook
Chris@0:    *   The name of the suggestion hook to complete.
Chris@0:    * @param array $cache
Chris@0:    *   The theme registry, as documented in
Chris@0:    *   \Drupal\Core\Theme\Registry::processExtension().
Chris@0:    */
Chris@0:   protected function completeSuggestion($hook, array &$cache) {
Chris@0:     $previous_hook = $hook;
Chris@0:     $incomplete_previous_hook = [];
Chris@0:     // Continue looping if the candidate hook doesn't exist or if the candidate
Chris@0:     // hook has incomplete preprocess functions, and if the candidate hook is a
Chris@0:     // suggestion (has a double underscore).
Chris@0:     while ((!isset($cache[$previous_hook]) || isset($cache[$previous_hook]['incomplete preprocess functions']))
Chris@0:       && $pos = strrpos($previous_hook, '__')) {
Chris@0:       // Find the first existing candidate hook that has incomplete preprocess
Chris@0:       // functions.
Chris@0:       if (isset($cache[$previous_hook]) && !$incomplete_previous_hook && isset($cache[$previous_hook]['incomplete preprocess functions'])) {
Chris@0:         $incomplete_previous_hook = $cache[$previous_hook];
Chris@0:         unset($incomplete_previous_hook['incomplete preprocess functions']);
Chris@0:       }
Chris@0:       $previous_hook = substr($previous_hook, 0, $pos);
Chris@0:       $this->mergePreprocessFunctions($hook, $previous_hook, $incomplete_previous_hook, $cache);
Chris@0:     }
Chris@0: 
Chris@0:     // In addition to processing suggestions, include base hooks.
Chris@0:     if (isset($cache[$hook]['base hook'])) {
Chris@0:       // In order to retain the additions from above, pass in the current hook
Chris@0:       // as the parent hook, otherwise it will be overwritten.
Chris@0:       $this->mergePreprocessFunctions($hook, $cache[$hook]['base hook'], $cache[$hook], $cache);
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Merges the source hook's preprocess functions into the destination hook's.
Chris@0:    *
Chris@0:    * @param string $destination_hook_name
Chris@0:    *   The name of the hook to merge preprocess functions to.
Chris@0:    * @param string $source_hook_name
Chris@0:    *   The name of the hook to merge preprocess functions from.
Chris@0:    * @param array $parent_hook
Chris@0:    *   The parent hook if it exists. Either an incomplete hook from suggestions
Chris@0:    *   or a base hook.
Chris@0:    * @param array $cache
Chris@0:    *   The theme registry, as documented in
Chris@0:    *   \Drupal\Core\Theme\Registry::processExtension().
Chris@0:    */
Chris@0:   protected function mergePreprocessFunctions($destination_hook_name, $source_hook_name, $parent_hook, array &$cache) {
Chris@0:     // If base hook exists clone of it for the preprocess function
Chris@0:     // without a template.
Chris@0:     // @see https://www.drupal.org/node/2457295
Chris@0:     if (isset($cache[$source_hook_name]) && (!isset($cache[$source_hook_name]['incomplete preprocess functions']) || !isset($cache[$destination_hook_name]['incomplete preprocess functions']))) {
Chris@0:       $cache[$destination_hook_name] = $parent_hook + $cache[$source_hook_name];
Chris@0:       if (isset($parent_hook['preprocess functions'])) {
Chris@0:         $diff = array_diff($parent_hook['preprocess functions'], $cache[$source_hook_name]['preprocess functions']);
Chris@0:         $cache[$destination_hook_name]['preprocess functions'] = array_merge($cache[$source_hook_name]['preprocess functions'], $diff);
Chris@0:       }
Chris@0:       // If a base hook isn't set, this is the actual base hook.
Chris@0:       if (!isset($cache[$source_hook_name]['base hook'])) {
Chris@0:         $cache[$destination_hook_name]['base hook'] = $source_hook_name;
Chris@0:       }
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Completes the theme registry adding discovered functions and hooks.
Chris@0:    *
Chris@0:    * @param array $cache
Chris@0:    *   The theme registry as documented in
Chris@0:    *   \Drupal\Core\Theme\Registry::processExtension().
Chris@0:    * @param \Drupal\Core\Theme\ActiveTheme $theme
Chris@0:    *   Current active theme.
Chris@0:    *
Chris@0:    * @see ::processExtension()
Chris@0:    */
Chris@0:   protected function postProcessExtension(array &$cache, ActiveTheme $theme) {
Chris@0:     // Gather prefixes. This will be used to limit the found functions to the
Chris@0:     // expected naming conventions.
Chris@0:     $prefixes = array_keys((array) $this->moduleHandler->getModuleList());
Chris@18:     foreach (array_reverse($theme->getBaseThemeExtensions()) as $base) {
Chris@0:       $prefixes[] = $base->getName();
Chris@0:     }
Chris@0:     if ($theme->getEngine()) {
Chris@0:       $prefixes[] = $theme->getEngine() . '_engine';
Chris@0:     }
Chris@0:     $prefixes[] = $theme->getName();
Chris@0: 
Chris@0:     $grouped_functions = $this->getPrefixGroupedUserFunctions($prefixes);
Chris@0: 
Chris@0:     // Collect all variable preprocess functions in the correct order.
Chris@0:     $suggestion_level = [];
Chris@0:     $matches = [];
Chris@0:     // Look for functions named according to the pattern and add them if they
Chris@0:     // have matching hooks in the registry.
Chris@0:     foreach ($prefixes as $prefix) {
Chris@0:       // Grep only the functions which are within the prefix group.
Chris@0:       list($first_prefix,) = explode('_', $prefix, 2);
Chris@0:       if (!isset($grouped_functions[$first_prefix])) {
Chris@0:         continue;
Chris@0:       }
Chris@0:       // Add the function and the name of the associated theme hook to the list
Chris@0:       // of preprocess functions grouped by suggestion specificity if a matching
Chris@0:       // base hook is found.
Chris@0:       foreach ($grouped_functions[$first_prefix] as $candidate) {
Chris@0:         if (preg_match("/^{$prefix}_preprocess_(((?:[^_]++|_(?!_))+)__.*)/", $candidate, $matches)) {
Chris@0:           if (isset($cache[$matches[2]])) {
Chris@0:             $level = substr_count($matches[1], '__');
Chris@0:             $suggestion_level[$level][$candidate] = $matches[1];
Chris@0:           }
Chris@0:         }
Chris@0:       }
Chris@0:     }
Chris@0: 
Chris@0:     // Add missing variable preprocessors. This is needed for modules that do
Chris@0:     // not explicitly register the hook. For example, when a theme contains a
Chris@0:     // variable preprocess function but it does not implement a template, it
Chris@0:     // will go missing. This will add the expected function. It also allows
Chris@0:     // modules or themes to have a variable process function based on a pattern
Chris@0:     // even if the hook does not exist.
Chris@0:     ksort($suggestion_level);
Chris@0:     foreach ($suggestion_level as $level => $item) {
Chris@0:       foreach ($item as $preprocessor => $hook) {
Chris@0:         if (isset($cache[$hook]['preprocess functions']) && !in_array($hook, $cache[$hook]['preprocess functions'])) {
Chris@0:           // Add missing preprocessor to existing hook.
Chris@0:           $cache[$hook]['preprocess functions'][] = $preprocessor;
Chris@0:         }
Chris@0:         elseif (!isset($cache[$hook]) && strpos($hook, '__')) {
Chris@0:           // Process non-existing hook and register it.
Chris@0:           // Look for a previously defined hook that is either a less specific
Chris@0:           // suggestion hook or the base hook.
Chris@0:           $this->completeSuggestion($hook, $cache);
Chris@0:           $cache[$hook]['preprocess functions'][] = $preprocessor;
Chris@0:         }
Chris@0:       }
Chris@0:     }
Chris@0:     // Inherit all base hook variable preprocess functions into suggestion
Chris@0:     // hooks. This ensures that derivative hooks have a complete set of variable
Chris@0:     // preprocess functions.
Chris@0:     foreach ($cache as $hook => $info) {
Chris@0:       // The 'base hook' is only applied to derivative hooks already registered
Chris@0:       // from a pattern. This is typically set from
Chris@0:       // drupal_find_theme_functions() and drupal_find_theme_templates().
Chris@0:       if (isset($info['incomplete preprocess functions'])) {
Chris@0:         $this->completeSuggestion($hook, $cache);
Chris@0:         unset($cache[$hook]['incomplete preprocess functions']);
Chris@0:       }
Chris@0: 
Chris@0:       // Optimize the registry.
Chris@0:       if (isset($cache[$hook]['preprocess functions']) && empty($cache[$hook]['preprocess functions'])) {
Chris@0:         unset($cache[$hook]['preprocess functions']);
Chris@0:       }
Chris@0:       // Ensure uniqueness.
Chris@0:       if (isset($cache[$hook]['preprocess functions'])) {
Chris@0:         $cache[$hook]['preprocess functions'] = array_unique($cache[$hook]['preprocess functions']);
Chris@0:       }
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Invalidates theme registry caches.
Chris@0:    *
Chris@0:    * To be called when the list of enabled extensions is changed.
Chris@0:    */
Chris@0:   public function reset() {
Chris@0:     // Reset the runtime registry.
Chris@0:     foreach ($this->runtimeRegistry as $runtime_registry) {
Chris@0:       $runtime_registry->clear();
Chris@0:     }
Chris@0:     $this->runtimeRegistry = [];
Chris@0: 
Chris@0:     $this->registry = [];
Chris@0:     Cache::invalidateTags(['theme_registry']);
Chris@0:     return $this;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function destruct() {
Chris@0:     foreach ($this->runtimeRegistry as $runtime_registry) {
Chris@0:       $runtime_registry->destruct();
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Gets all user functions grouped by the word before the first underscore.
Chris@0:    *
Chris@0:    * @param $prefixes
Chris@0:    *   An array of function prefixes by which the list can be limited.
Chris@0:    * @return array
Chris@0:    *   Functions grouped by the first prefix.
Chris@0:    */
Chris@0:   public function getPrefixGroupedUserFunctions($prefixes = []) {
Chris@0:     $functions = get_defined_functions();
Chris@0: 
Chris@0:     // If a list of prefixes is supplied, trim down the list to those items
Chris@0:     // only as efficiently as possible.
Chris@0:     if ($prefixes) {
Chris@0:       $theme_functions = preg_grep('/^(' . implode(')|(', $prefixes) . ')_/', $functions['user']);
Chris@0:     }
Chris@0:     else {
Chris@0:       $theme_functions = $functions['user'];
Chris@0:     }
Chris@0: 
Chris@0:     $grouped_functions = [];
Chris@0:     // Splitting user defined functions into groups by the first prefix.
Chris@0:     foreach ($theme_functions as $function) {
Chris@0:       list($first_prefix,) = explode('_', $function, 2);
Chris@0:       $grouped_functions[$first_prefix][] = $function;
Chris@0:     }
Chris@0: 
Chris@0:     return $grouped_functions;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Wraps drupal_get_path().
Chris@0:    *
Chris@0:    * @param string $module
Chris@0:    *   The name of the item for which the path is requested.
Chris@0:    *
Chris@0:    * @return string
Chris@0:    */
Chris@0:   protected function getPath($module) {
Chris@0:     return drupal_get_path('module', $module);
Chris@0:   }
Chris@0: 
Chris@0: }