diff core/lib/Drupal/Core/Plugin/DefaultPluginManager.php @ 0:4c8ae668cc8c

Initial import (non-working)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/core/lib/Drupal/Core/Plugin/DefaultPluginManager.php	Wed Nov 29 16:09:58 2017 +0000
@@ -0,0 +1,367 @@
+<?php
+
+namespace Drupal\Core\Plugin;
+
+use Drupal\Component\Plugin\Definition\PluginDefinitionInterface;
+use Drupal\Component\Plugin\Discovery\CachedDiscoveryInterface;
+use Drupal\Core\Cache\CacheableDependencyInterface;
+use Drupal\Core\Cache\CacheBackendInterface;
+use Drupal\Core\Cache\UseCacheBackendTrait;
+use Drupal\Component\Plugin\Discovery\DiscoveryCachedTrait;
+use Drupal\Core\Plugin\Discovery\ContainerDerivativeDiscoveryDecorator;
+use Drupal\Component\Plugin\PluginManagerBase;
+use Drupal\Component\Plugin\PluginManagerInterface;
+use Drupal\Component\Utility\NestedArray;
+use Drupal\Core\Cache\Cache;
+use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\Core\Plugin\Discovery\AnnotatedClassDiscovery;
+use Drupal\Core\Plugin\Factory\ContainerFactory;
+
+/**
+ * Base class for plugin managers.
+ *
+ * @ingroup plugin_api
+ */
+class DefaultPluginManager extends PluginManagerBase implements PluginManagerInterface, CachedDiscoveryInterface, CacheableDependencyInterface {
+
+  use DiscoveryCachedTrait;
+  use UseCacheBackendTrait;
+
+  /**
+   * The cache key.
+   *
+   * @var string
+   */
+  protected $cacheKey;
+
+  /**
+   * An array of cache tags to use for the cached definitions.
+   *
+   * @var array
+   */
+  protected $cacheTags = [];
+
+  /**
+   * Name of the alter hook if one should be invoked.
+   *
+   * @var string
+   */
+  protected $alterHook;
+
+  /**
+   * The subdirectory within a namespace to look for plugins, or FALSE if the
+   * plugins are in the top level of the namespace.
+   *
+   * @var string|bool
+   */
+  protected $subdir;
+
+  /**
+   * The module handler to invoke the alter hook.
+   *
+   * @var \Drupal\Core\Extension\ModuleHandlerInterface
+   */
+  protected $moduleHandler;
+
+  /**
+   * A set of defaults to be referenced by $this->processDefinition() if
+   * additional processing of plugins is necessary or helpful for development
+   * purposes.
+   *
+   * @var array
+   */
+  protected $defaults = [];
+
+  /**
+   * The name of the annotation that contains the plugin definition.
+   *
+   * @var string
+   */
+  protected $pluginDefinitionAnnotationName;
+
+  /**
+   * The interface each plugin should implement.
+   *
+   * @var string|null
+   */
+  protected $pluginInterface;
+
+  /**
+   * An object that implements \Traversable which contains the root paths
+   * keyed by the corresponding namespace to look for plugin implementations.
+   *
+   * @var \Traversable
+   */
+  protected $namespaces;
+
+  /**
+   * Additional namespaces the annotation discovery mechanism should scan for
+   * annotation definitions.
+   *
+   * @var string[]
+   */
+  protected $additionalAnnotationNamespaces = [];
+
+  /**
+   * Creates the discovery object.
+   *
+   * @param string|bool $subdir
+   *   The plugin's subdirectory, for example Plugin/views/filter.
+   * @param \Traversable $namespaces
+   *   An object that implements \Traversable which contains the root paths
+   *   keyed by the corresponding namespace to look for plugin implementations.
+   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
+   *   The module handler.
+   * @param string|null $plugin_interface
+   *   (optional) The interface each plugin should implement.
+   * @param string $plugin_definition_annotation_name
+   *   (optional) The name of the annotation that contains the plugin definition.
+   *   Defaults to 'Drupal\Component\Annotation\Plugin'.
+   * @param string[] $additional_annotation_namespaces
+   *   (optional) Additional namespaces to scan for annotation definitions.
+   */
+  public function __construct($subdir, \Traversable $namespaces, ModuleHandlerInterface $module_handler, $plugin_interface = NULL, $plugin_definition_annotation_name = 'Drupal\Component\Annotation\Plugin', array $additional_annotation_namespaces = []) {
+    $this->subdir = $subdir;
+    $this->namespaces = $namespaces;
+    $this->pluginDefinitionAnnotationName = $plugin_definition_annotation_name;
+    $this->pluginInterface = $plugin_interface;
+    $this->moduleHandler = $module_handler;
+    $this->additionalAnnotationNamespaces = $additional_annotation_namespaces;
+  }
+
+  /**
+   * Initialize the cache backend.
+   *
+   * Plugin definitions are cached using the provided cache backend.
+   *
+   * @param \Drupal\Core\Cache\CacheBackendInterface $cache_backend
+   *   Cache backend instance to use.
+   * @param string $cache_key
+   *   Cache key prefix to use.
+   * @param array $cache_tags
+   *   (optional) When providing a list of cache tags, the cached plugin
+   *   definitions are tagged with the provided cache tags. These cache tags can
+   *   then be used to clear the corresponding cached plugin definitions. Note
+   *   that this should be used with care! For clearing all cached plugin
+   *   definitions of a plugin manager, call that plugin manager's
+   *   clearCachedDefinitions() method. Only use cache tags when cached plugin
+   *   definitions should be cleared along with other, related cache entries.
+   */
+  public function setCacheBackend(CacheBackendInterface $cache_backend, $cache_key, array $cache_tags = []) {
+    assert('\Drupal\Component\Assertion\Inspector::assertAllStrings($cache_tags)', 'Cache Tags must be strings.');
+    $this->cacheBackend = $cache_backend;
+    $this->cacheKey = $cache_key;
+    $this->cacheTags = $cache_tags;
+  }
+
+  /**
+   * Initializes the alter hook.
+   *
+   * @param string $alter_hook
+   *   Name of the alter hook; for example, to invoke
+   *   hook_mymodule_data_alter() pass in "mymodule_data".
+   */
+  protected function alterInfo($alter_hook) {
+    $this->alterHook = $alter_hook;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getDefinitions() {
+    $definitions = $this->getCachedDefinitions();
+    if (!isset($definitions)) {
+      $definitions = $this->findDefinitions();
+      $this->setCachedDefinitions($definitions);
+    }
+    return $definitions;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function clearCachedDefinitions() {
+    if ($this->cacheBackend) {
+      if ($this->cacheTags) {
+        // Use the cache tags to clear the cache.
+        Cache::invalidateTags($this->cacheTags);
+      }
+      else {
+        $this->cacheBackend->delete($this->cacheKey);
+      }
+    }
+    $this->definitions = NULL;
+  }
+
+  /**
+   * Returns the cached plugin definitions of the decorated discovery class.
+   *
+   * @return array|null
+   *   On success this will return an array of plugin definitions. On failure
+   *   this should return NULL, indicating to other methods that this has not
+   *   yet been defined. Success with no values should return as an empty array
+   *   and would actually be returned by the getDefinitions() method.
+   */
+  protected function getCachedDefinitions() {
+    if (!isset($this->definitions) && $cache = $this->cacheGet($this->cacheKey)) {
+      $this->definitions = $cache->data;
+    }
+    return $this->definitions;
+  }
+
+  /**
+   * Sets a cache of plugin definitions for the decorated discovery class.
+   *
+   * @param array $definitions
+   *   List of definitions to store in cache.
+   */
+  protected function setCachedDefinitions($definitions) {
+    $this->cacheSet($this->cacheKey, $definitions, Cache::PERMANENT, $this->cacheTags);
+    $this->definitions = $definitions;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function useCaches($use_caches = FALSE) {
+    $this->useCaches = $use_caches;
+    if (!$use_caches) {
+      $this->definitions = NULL;
+    }
+  }
+
+  /**
+   * Performs extra processing on plugin definitions.
+   *
+   * By default we add defaults for the type to the definition. If a type has
+   * additional processing logic they can do that by replacing or extending the
+   * method.
+   */
+  public function processDefinition(&$definition, $plugin_id) {
+    // Only array-based definitions can have defaults merged in.
+    if (is_array($definition) && !empty($this->defaults) && is_array($this->defaults)) {
+      $definition = NestedArray::mergeDeep($this->defaults, $definition);
+    }
+
+    // Keep class definitions standard with no leading slash.
+    if ($definition instanceof PluginDefinitionInterface) {
+      $definition->setClass(ltrim($definition->getClass(), '\\'));
+    }
+    elseif (is_array($definition) && isset($definition['class'])) {
+      $definition['class'] = ltrim($definition['class'], '\\');
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getDiscovery() {
+    if (!$this->discovery) {
+      $discovery = new AnnotatedClassDiscovery($this->subdir, $this->namespaces, $this->pluginDefinitionAnnotationName, $this->additionalAnnotationNamespaces);
+      $this->discovery = new ContainerDerivativeDiscoveryDecorator($discovery);
+    }
+    return $this->discovery;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getFactory() {
+    if (!$this->factory) {
+      $this->factory = new ContainerFactory($this, $this->pluginInterface);
+    }
+    return $this->factory;
+  }
+
+  /**
+   * Finds plugin definitions.
+   *
+   * @return array
+   *   List of definitions to store in cache.
+   */
+  protected function findDefinitions() {
+    $definitions = $this->getDiscovery()->getDefinitions();
+    foreach ($definitions as $plugin_id => &$definition) {
+      $this->processDefinition($definition, $plugin_id);
+    }
+    $this->alterDefinitions($definitions);
+    // If this plugin was provided by a module that does not exist, remove the
+    // plugin definition.
+    foreach ($definitions as $plugin_id => $plugin_definition) {
+      $provider = $this->extractProviderFromDefinition($plugin_definition);
+      if ($provider && !in_array($provider, ['core', 'component']) && !$this->providerExists($provider)) {
+        unset($definitions[$plugin_id]);
+      }
+    }
+    return $definitions;
+  }
+
+  /**
+   * Extracts the provider from a plugin definition.
+   *
+   * @param mixed $plugin_definition
+   *   The plugin definition. Usually either an array or an instance of
+   *   \Drupal\Component\Plugin\Definition\PluginDefinitionInterface
+   *
+   * @return string|null
+   *   The provider string, if it exists. NULL otherwise.
+   */
+  protected function extractProviderFromDefinition($plugin_definition) {
+    if ($plugin_definition instanceof PluginDefinitionInterface) {
+      return $plugin_definition->getProvider();
+    }
+
+    // Attempt to convert the plugin definition to an array.
+    if (is_object($plugin_definition)) {
+      $plugin_definition = (array) $plugin_definition;
+    }
+
+    if (isset($plugin_definition['provider'])) {
+      return $plugin_definition['provider'];
+    }
+  }
+
+  /**
+   * Invokes the hook to alter the definitions if the alter hook is set.
+   *
+   * @param $definitions
+   *   The discovered plugin definitions.
+   */
+  protected function alterDefinitions(&$definitions) {
+    if ($this->alterHook) {
+      $this->moduleHandler->alter($this->alterHook, $definitions);
+    }
+  }
+
+  /**
+   * Determines if the provider of a definition exists.
+   *
+   * @return bool
+   *   TRUE if provider exists, FALSE otherwise.
+   */
+  protected function providerExists($provider) {
+    return $this->moduleHandler->moduleExists($provider);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getCacheContexts() {
+    return [];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getCacheTags() {
+    return $this->cacheTags;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getCacheMaxAge() {
+    return Cache::PERMANENT;
+  }
+
+}