/**
* Builds the theme registry cache.
*
* Theme hook definitions are collected in the following order:
* - Modules
* - Base theme engines
* - Base themes
* - Theme engine
* - Theme
*
* All theme hook definitions are essentially just collated and merged in the
* above order. However, various extension-specific default values and
* customizations are required; e.g., to record the effective file path for
* theme template. Therefore, this method first collects all extensions per
* type, and then dispatches the processing for each extension to
* processExtension().
*
* After completing the collection, modules are allowed to alter it. Lastly,
* any derived and incomplete theme hook definitions that are hook suggestions
* for base hooks (e.g., 'block__node' for the base hook 'block') need to be
* determined based on the full registry and classified as 'base hook'.
*
* @see _theme()
* @see hook_theme_registry_alter()
*
* @return \Drupal\Core\Utility\ThemeRegistry
* The build theme registry.
*/
protected function build()
{
$cache = array();
// First, preprocess the theme hooks advertised by modules. This will
// serve as the basic registry. Since the list of enabled modules is the
// same regardless of the theme used, this is cached in its own entry to
// save building it for every theme.
if ($cached = $this->cache->get('theme_registry:build:modules')) {
$cache = $cached->data;
} else {
foreach ($this->moduleHandler->getImplementations('theme') as $module) {
$this->processExtension($cache, $module, 'module', $module, $this->getPath($module));
}
// Only cache this registry if all modules are loaded.
if ($this->moduleHandler->isLoaded()) {
$this->cache->set("theme_registry:build:modules", $cache, Cache::PERMANENT, array('theme_registry' => TRUE));
}
}
// Process each base theme.
foreach ($this->baseThemes as $base) {
// If the base theme uses a theme engine, process its hooks.
$base_path = $base->getPath();
if ($this->engine) {
$this->processExtension($cache, $this->engine, 'base_theme_engine', $base->getName(), $base_path);
}
$this->processExtension($cache, $base->getName(), 'base_theme', $base->getName(), $base_path);
}
// And then the same thing, but for the theme.
if ($this->engine) {
$this->processExtension($cache, $this->engine, 'theme_engine', $this->theme->getName(), $this->theme->getPath());
}
// Finally, hooks provided by the theme itself.
$this->processExtension($cache, $this->theme->getName(), 'theme', $this->theme->getName(), $this->theme->getPath());
// Let modules alter the registry.
$this->moduleHandler->alter('theme_registry', $cache);
// @todo Implement more reduction of the theme registry entry.
// Optimize the registry to not have empty arrays for functions.
foreach ($cache as $hook => $info) {
if (empty($info['preprocess functions'])) {
unset($cache[$hook]['preprocess functions']);
}
}
$this->registry = $cache;
return $this->registry;
}
/**
* Builds the theme registry cache.
*
* Theme hook definitions are collected in the following order:
* - Modules
* - Base theme engines
* - Base themes
* - Theme engine
* - Theme
*
* All theme hook definitions are essentially just collated and merged in the
* above order. However, various extension-specific default values and
* customizations are required; e.g., to record the effective file path for
* theme template. Therefore, this method first collects all extensions per
* type, and then dispatches the processing for each extension to
* processExtension().
*
* After completing the collection, modules are allowed to alter it. Lastly,
* any derived and incomplete theme hook definitions that are hook suggestions
* for base hooks (e.g., 'block__node' for the base hook 'block') need to be
* determined based on the full registry and classified as 'base hook'.
*
* See the @link themeable Default theme implementations topic @endlink for
* details.
*
* @return \Drupal\Core\Utility\ThemeRegistry
* The build theme registry.
*
* @see hook_theme_registry_alter()
*/
protected function build()
{
$cache = array();
// First, preprocess the theme hooks advertised by modules. This will
// serve as the basic registry. Since the list of enabled modules is the
// same regardless of the theme used, this is cached in its own entry to
// save building it for every theme.
if ($cached = $this->cache->get('theme_registry:build:modules')) {
$cache = $cached->data;
} else {
foreach ($this->moduleHandler->getImplementations('theme') as $module) {
$this->processExtension($cache, $module, 'module', $module, $this->getPath($module));
}
// Only cache this registry if all modules are loaded.
if ($this->moduleHandler->isLoaded()) {
$this->cache->set("theme_registry:build:modules", $cache, Cache::PERMANENT, array('theme_registry'));
}
}
// Process each base theme.
// Ensure that we start with the root of the parents, so that both CSS files
// and preprocess functions comes first.
foreach (array_reverse($this->theme->getBaseThemes()) as $base) {
// If the base theme uses a theme engine, process its hooks.
$base_path = $base->getPath();
if ($this->theme->getEngine()) {
$this->processExtension($cache, $this->theme->getEngine(), 'base_theme_engine', $base->getName(), $base_path);
}
$this->processExtension($cache, $base->getName(), 'base_theme', $base->getName(), $base_path);
}
// And then the same thing, but for the theme.
if ($this->theme->getEngine()) {
$this->processExtension($cache, $this->theme->getEngine(), 'theme_engine', $this->theme->getName(), $this->theme->getPath());
}
// Hooks provided by the theme itself.
$this->processExtension($cache, $this->theme->getName(), 'theme', $this->theme->getName(), $this->theme->getPath());
// Discover and add all preprocess functions for theme hook suggestions.
$this->postProcessExtension($cache, $this->theme);
// Let modules and themes alter the registry.
$this->moduleHandler->alter('theme_registry', $cache);
$this->themeManager->alterForTheme($this->theme, 'theme_registry', $cache);
// @todo Implement more reduction of the theme registry entry.
// Optimize the registry to not have empty arrays for functions.
foreach ($cache as $hook => $info) {
if (empty($info['preprocess functions'])) {
unset($cache[$hook]['preprocess functions']);
}
}
$this->registry[$this->theme->getName()] = $cache;
return $this->registry[$this->theme->getName()];
}
/**
* {@inheritdoc}
*/
public function render($hook, array $variables)
{
static $default_attributes;
$active_theme = $this->getActiveTheme();
// If called before all modules are loaded, we do not necessarily have a
// full theme registry to work with, and therefore cannot process the theme
// request properly. See also \Drupal\Core\Theme\Registry::get().
if (!$this->moduleHandler->isLoaded() && !defined('MAINTENANCE_MODE')) {
throw new \Exception('The theme implementations may not be rendered until all modules are loaded.');
}
$theme_registry = $this->themeRegistry->getRuntime();
// If an array of hook candidates were passed, use the first one that has an
// implementation.
if (is_array($hook)) {
foreach ($hook as $candidate) {
if ($theme_registry->has($candidate)) {
break;
}
}
$hook = $candidate;
}
// Save the original theme hook, so it can be supplied to theme variable
// preprocess callbacks.
$original_hook = $hook;
// If there's no implementation, check for more generic fallbacks.
// If there's still no implementation, log an error and return an empty
// string.
if (!$theme_registry->has($hook)) {
// Iteratively strip everything after the last '__' delimiter, until an
// implementation is found.
while ($pos = strrpos($hook, '__')) {
$hook = substr($hook, 0, $pos);
if ($theme_registry->has($hook)) {
break;
}
}
if (!$theme_registry->has($hook)) {
// Only log a message when not trying theme suggestions ($hook being an
// array).
if (!isset($candidate)) {
\Drupal::logger('theme')->warning('Theme hook %hook not found.', array('%hook' => $hook));
}
// There is no theme implementation for the hook passed. Return FALSE so
// the function calling
// \Drupal\Core\Theme\ThemeManagerInterface::render() can differentiate
// between a hook that exists and renders an empty string, and a hook
// that is not implemented.
return FALSE;
}
}
$info = $theme_registry->get($hook);
// If a renderable array is passed as $variables, then set $variables to
// the arguments expected by the theme function.
if (isset($variables['#theme']) || isset($variables['#theme_wrappers'])) {
$element = $variables;
$variables = array();
if (isset($info['variables'])) {
foreach (array_keys($info['variables']) as $name) {
if (isset($element["#{$name}"]) || array_key_exists("#{$name}", $element)) {
$variables[$name] = $element["#{$name}"];
}
}
} else {
$variables[$info['render element']] = $element;
// Give a hint to render engines to prevent infinite recursion.
$variables[$info['render element']]['#render_children'] = TRUE;
}
}
// Merge in argument defaults.
if (!empty($info['variables'])) {
$variables += $info['variables'];
} elseif (!empty($info['render element'])) {
$variables += array($info['render element'] => array());
}
// Supply original caller info.
$variables += array('theme_hook_original' => $original_hook);
// Set base hook for later use. For example if '#theme' => 'node__article'
// is called, we run hook_theme_suggestions_node_alter() rather than
// hook_theme_suggestions_node__article_alter(), and also pass in the base
// hook as the last parameter to the suggestions alter hooks.
if (isset($info['base hook'])) {
$base_theme_hook = $info['base hook'];
} else {
$base_theme_hook = $hook;
}
// Invoke hook_theme_suggestions_HOOK().
$suggestions = $this->moduleHandler->invokeAll('theme_suggestions_' . $base_theme_hook, array($variables));
// If the theme implementation was invoked with a direct theme suggestion
// like '#theme' => 'node__article', add it to the suggestions array before
// invoking suggestion alter hooks.
if (isset($info['base hook'])) {
$suggestions[] = $hook;
}
// Invoke hook_theme_suggestions_alter() and
// hook_theme_suggestions_HOOK_alter().
$hooks = array('theme_suggestions', 'theme_suggestions_' . $base_theme_hook);
$this->moduleHandler->alter($hooks, $suggestions, $variables, $base_theme_hook);
$this->alter($hooks, $suggestions, $variables, $base_theme_hook);
// Check if each suggestion exists in the theme registry, and if so,
// use it instead of the base hook. For example, a function may use
// '#theme' => 'node', but a module can add 'node__article' as a suggestion
// via hook_theme_suggestions_HOOK_alter(), enabling a theme to have
// an alternate template file for article nodes.
foreach (array_reverse($suggestions) as $suggestion) {
if ($theme_registry->has($suggestion)) {
$info = $theme_registry->get($suggestion);
break;
}
}
// Include a file if the theme function or variable preprocessor is held
// elsewhere.
if (!empty($info['includes'])) {
foreach ($info['includes'] as $include_file) {
include_once $this->root . '/' . $include_file;
}
}
// Invoke the variable preprocessors, if any.
if (isset($info['base hook'])) {
$base_hook = $info['base hook'];
$base_hook_info = $theme_registry->get($base_hook);
// Include files required by the base hook, since its variable
// preprocessors might reside there.
if (!empty($base_hook_info['includes'])) {
foreach ($base_hook_info['includes'] as $include_file) {
include_once $this->root . '/' . $include_file;
}
}
if (isset($base_hook_info['preprocess functions'])) {
// Set a variable for the 'theme_hook_suggestion'. This is used to
// maintain backwards compatibility with template engines.
$theme_hook_suggestion = $hook;
}
}
if (isset($info['preprocess functions'])) {
foreach ($info['preprocess functions'] as $preprocessor_function) {
if (function_exists($preprocessor_function)) {
$preprocessor_function($variables, $hook, $info);
}
}
// Allow theme preprocess functions to set $variables['#attached'] and
// $variables['#cache'] and use them like the corresponding element
// properties on render arrays. In Drupal 8, this is the (only) officially
// supported method of attaching bubbleable metadata from preprocess
// functions. Assets attached here should be associated with the template
// that we are preprocessing variables for.
$preprocess_bubbleable = [];
foreach (['#attached', '#cache'] as $key) {
if (isset($variables[$key])) {
$preprocess_bubbleable[$key] = $variables[$key];
}
}
// We do not allow preprocess functions to define cacheable elements.
unset($preprocess_bubbleable['#cache']['keys']);
if ($preprocess_bubbleable) {
// @todo Inject the Renderer in https://www.drupal.org/node/2529438.
drupal_render($preprocess_bubbleable);
}
}
// Generate the output using either a function or a template.
$output = '';
if (isset($info['function'])) {
if (function_exists($info['function'])) {
// Theme functions do not render via the theme engine, so the output is
// not autoescaped. However, we can only presume that the theme function
// has been written correctly and that the markup is safe.
$output = Markup::create($info['function']($variables));
}
} else {
$render_function = 'twig_render_template';
$extension = '.html.twig';
// The theme engine may use a different extension and a different
// renderer.
$theme_engine = $active_theme->getEngine();
if (isset($theme_engine)) {
if ($info['type'] != 'module') {
if (function_exists($theme_engine . '_render_template')) {
$render_function = $theme_engine . '_render_template';
}
$extension_function = $theme_engine . '_extension';
if (function_exists($extension_function)) {
$extension = $extension_function();
}
}
}
// In some cases, a template implementation may not have had
// template_preprocess() run (for example, if the default implementation
// is a function, but a template overrides that default implementation).
// In these cases, a template should still be able to expect to have
// access to the variables provided by template_preprocess(), so we add
// them here if they don't already exist. We don't want the overhead of
// running template_preprocess() twice, so we use the 'directory' variable
// to determine if it has already run, which while not completely
// intuitive, is reasonably safe, and allows us to save on the overhead of
// adding some new variable to track that.
if (!isset($variables['directory'])) {
$default_template_variables = array();
template_preprocess($default_template_variables, $hook, $info);
$variables += $default_template_variables;
}
if (!isset($default_attributes)) {
$default_attributes = new Attribute();
}
foreach (array('attributes', 'title_attributes', 'content_attributes') as $key) {
if (isset($variables[$key]) && !$variables[$key] instanceof Attribute) {
if ($variables[$key]) {
$variables[$key] = new Attribute($variables[$key]);
} else {
// Create empty attributes.
$variables[$key] = clone $default_attributes;
}
}
}
// Render the output using the template file.
$template_file = $info['template'] . $extension;
if (isset($info['path'])) {
$template_file = $info['path'] . '/' . $template_file;
}
// Add the theme suggestions to the variables array just before rendering
// the template for backwards compatibility with template engines.
$variables['theme_hook_suggestions'] = $suggestions;
// For backwards compatibility, pass 'theme_hook_suggestion' on to the
// template engine. This is only set when calling a direct suggestion like
// '#theme' => 'menu__shortcut_default' when the template exists in the
// current theme.
if (isset($theme_hook_suggestion)) {
$variables['theme_hook_suggestion'] = $theme_hook_suggestion;
}
$output = $render_function($template_file, $variables);
}
return $output instanceof MarkupInterface ? $output : (string) $output;
}
