Issue #1869566 by tim.plunkett, dawehner: Allow any collection of plugins to be lazily instantiated.

core/lib/Drupal/Component/Plugin/PluginBag.php

@@ -0,0 +1,179 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Component\Plugin\PluginBag.
+ */
+
+namespace Drupal\Component\Plugin;
+
+/**
+ * Defines an object which stores multiple plugin instances to lazy load them.
+ *
+ * The \ArrayAccess implementation is only for backwards compatibility, it is
+ * deprecated and should not be used by new code.
+ */
+abstract class PluginBag implements \ArrayAccess, \Iterator, \Countable {
+
+  /**
+   * Stores all instantiated plugins.
+   *
+   * @var array
+   */
+  protected $pluginInstances = array();
+
+  /**
+   * Stores the IDs of all potential plugin instances.
+   *
+   * @var array
+   */
+  protected $instanceIDs = array();
+
+  /**
+   * Initializes a plugin and stores the result in $this->pluginInstances.
+   *
+   * @param string $instance_id
+   *   The ID of the plugin instance to initialize.
+   */
+  abstract protected function initializePlugin($instance_id);
+
+  /**
+   * Clears all instantiated plugins.
+   */
+  public function clear() {
+    $this->pluginInstances = array();
+  }
+
+  /**
+   * Determines if a plugin instance exists.
+   *
+   * @param string $instance_id
+   *   The ID of the plugin instance to check.
+   *
+   * @return bool
+   *   TRUE if the plugin instance exists, FALSE otherwise.
+   */
+  public function has($instance_id) {
+    return isset($this->pluginInstances[$instance_id]) || isset($this->instanceIDs[$instance_id]);
+  }
+
+  /**
+   * Retrieves a plugin instance, initializing it if necessary.
+   *
+   * @param string $instance_id
+   *   The ID of the plugin instance being retrieved.
+   */
+  public function get($instance_id) {
+    if (!isset($this->pluginInstances[$instance_id])) {
+      $this->initializePlugin($instance_id);
+    }
+    return $this->pluginInstances[$instance_id];
+  }
+
+  /**
+   * Stores an initialized plugin.
+   *
+   * @param string $instance_id
+   *   The ID of the plugin instance being stored.
+   * @param mixed $value
+   *   An instantiated plugin.
+   */
+  public function set($instance_id, $value) {
+    $this->pluginInstances[$instance_id] = $value;
+  }
+
+  /**
+   * Removes an initialized plugin.
+   *
+   * The plugin can still be used, it will be reinitialized.
+   *
+   * @param string $instance_id
+   *   The ID of the plugin instance to remove.
+   */
+  public function remove($instance_id) {
+    unset($this->pluginInstances[$instance_id]);
+  }
+
+  /**
+   * Implements \ArrayAccess::offsetExists().
+   *
+   * This is deprecated, use \Drupal\Component\Plugin\PluginBag::has().
+   */
+  public function offsetExists($offset) {
+    return isset($this->pluginInstances[$offset]) || isset($this->instanceIDs[$offset]);
+  }
+
+  /**
+   * Implements \ArrayAccess::offsetGet().
+   *
+   * This is deprecated, use \Drupal\Component\Plugin\PluginBag::get().
+   */
+  public function offsetGet($offset) {
+    if (!isset($this->pluginInstances[$offset])) {
+      $this->initializePlugin($offset);
+    }
+    return $this->pluginInstances[$offset];
+  }
+
+  /**
+   * Implements \ArrayAccess::offsetSet().
+   *
+   * This is deprecated, use \Drupal\Component\Plugin\PluginBag::set().
+   */
+  public function offsetSet($offset, $value) {
+    $this->pluginInstances[$offset] = $value;
+  }
+
+  /**
+   * Implements \ArrayAccess::offsetUnset().
+   *
+   * This is deprecated, use \Drupal\Component\Plugin\PluginBag::remove().
+   */
+  public function offsetUnset($offset) {
+    unset($this->pluginInstances[$offset]);
+  }
+
+  /**
+   * Implements \Iterator::current().
+   */
+  public function current() {
+    return $this->offsetGet($this->key());
+  }
+
+  /**
+   * Implements \Iterator::next().
+   */
+  public function next() {
+    next($this->instanceIDs);
+  }
+
+  /**
+   * Implements \Iterator::key().
+   */
+  public function key() {
+    return key($this->instanceIDs);
+  }
+
+  /**
+   * Implements \Iterator::valid().
+   */
+  public function valid() {
+    $key = key($this->instanceIDs);
+    return $key !== NULL && $key !== FALSE;
+  }
+
+  /**
+   * Implements \Iterator::rewind().
+   */
+  public function rewind() {
+    reset($this->instanceIDs);
+  }
+
+  /**
+   * Implements \Countable::count().
+   */
+  public function count() {
+    return count($this->instanceIDs);
+  }
+
+}

core/modules/system/lib/Drupal/system/Tests/Plugin/PluginBagTest.php

@@ -0,0 +1,78 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\system\Tests\Plugin\PluginBagTest.
+ */
+
+namespace Drupal\system\Tests\Plugin;
+
+use Drupal\plugin_test\Plugin\TestPluginBag;
+use Drupal\plugin_test\Plugin\plugin_test\mock_block\MockTestPluginInterface;
+
+/**
+ * Tests the generic plugin bag.
+ *
+ * @see \Drupal\Component\Plugin\PluginBag
+ * @see \Drupal\plugin_test\Plugin\TestPluginBag
+ */
+class PluginBagTest extends PluginTestBase {
+
+  public static function getInfo() {
+    return array(
+      'name' => 'Plugin Bag',
+      'description' => 'Tests the generic plugin bag.',
+      'group' => 'Plugin API',
+    );
+  }
+
+  /**
+   * Tests the generic plugin bag.
+   */
+  protected function testPluginBag() {
+    // Setup the plugin bag as well as the available plugin definitions.
+    $plugin_bag = new TestPluginBag($this->mockBlockManager);
+    $definitions = $this->mockBlockManager->getDefinitions();
+    $first_instance_id = key($definitions);
+
+    foreach ($definitions as $instance_id => $definition) {
+      $this->assertTrue(isset($plugin_bag[$instance_id]), format_string('Plugin instance @instance_id exits on the bag', array('@instance_id' => $instance_id)));
+      $this->assertTrue($plugin_bag->has($instance_id), format_string('Plugin instance @instance_id exits on the bag', array('@instance_id' => $instance_id)));
+      $this->assertTrue($plugin_bag[$instance_id] instanceof $definition['class'], 'Getting the plugin from the bag worked.');
+      $this->assertTrue($plugin_bag->get($instance_id) instanceof $definition['class'], 'Getting the plugin from the bag worked.');
+    }
+
+    // A non existing instance_id shouldn't exist on the bag.
+    $random_name = $this->randomName();
+    $random_name_2 = $this->randomName();
+    $this->assertFalse(isset($plugin_bag[$random_name]), 'A random instance_id should not exist on the plugin bag.');
+    $this->assertFalse($plugin_bag->has($random_name_2), 'A random instance_id should not exist on the plugin bag.');
+
+    // Set a new plugin instance to the bag, to test offsetSet.
+    $plugin_bag[$random_name] = $this->mockBlockManager->createInstance($first_instance_id, array());
+    $plugin_bag->set($random_name_2, $this->mockBlockManager->createInstance($first_instance_id, array()));
+    $this->assertTrue(isset($plugin_bag[$random_name]), 'A random instance_id should exist after manual setting on the plugin bag.');
+    $this->assertTrue(isset($plugin_bag[$random_name_2]), 'A random instance_id should exist after manual setting on the plugin bag.');
+    $this->assertTrue($plugin_bag->has($random_name), 'A random instance_id should exist after manual setting on the plugin bag.');
+    $this->assertTrue($plugin_bag->has($random_name_2), 'A random instance_id should exist after manual setting on the plugin bag.');
+
+    // Remove the previous added element and check whether it still exists.
+    unset($plugin_bag[$random_name]);
+    $plugin_bag->remove($random_name_2);
+    $this->assertFalse(isset($plugin_bag[$random_name]), 'A random instance_id should not exist on the plugin bag after removing.');
+    $this->assertFalse(isset($plugin_bag[$random_name_2]), 'A random instance_id should not exist on the plugin bag after removing.');
+    $this->assertFalse($plugin_bag->has($random_name), 'A random instance_id should not exist on the plugin bag after removing.');
+    $this->assertFalse($plugin_bag->has($random_name_2), 'A random instance_id should not exist on the plugin bag after removing.');
+
+    // Test that iterating over the plugins work.
+    $expected_instance_ids = array_keys($definitions);
+    $counter = 0;
+    foreach ($plugin_bag as $instance_id => $plugin) {
+      $this->assertEqual($expected_instance_ids[$counter], $instance_id, format_string('The iteration works as expected for plugin instance @instance_id', array('@instance_id' => $instance_id)));
+      $counter++;
+    }
+
+    $this->assertEqual(count($plugin_bag), count($expected_instance_ids), 'The amount of items in plugin bag is as expected.');
+  }
+
+}

core/modules/system/tests/modules/plugin_test/lib/Drupal/plugin_test/Plugin/TestPluginBag.php

@@ -0,0 +1,49 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\plugin_test\Plugin\TestPluginBag.
+ */
+
+namespace Drupal\plugin_test\Plugin;
+
+use Drupal\Component\Plugin\PluginBag;
+use Drupal\Component\Plugin\PluginManagerInterface;
+
+/**
+ * Defines a plugin bag which uses fruit plugins.
+ */
+class TestPluginBag extends PluginBag {
+
+  /**
+   * Stores the plugin manager used by this bag.
+   *
+   * @var \Drupal\Component\Plugin\PluginManagerInterface
+   */
+  protected $manager;
+
+  /**
+   * Constructs a TestPluginBag object.
+   *
+   * @param \Drupal\Component\Plugin\PluginManagerInterface $manager
+   *   The plugin manager that handles test plugins.
+   */
+  public function __construct(PluginManagerInterface $manager) {
+    $this->manager = $manager;
+
+    $this->instanceIDs = drupal_map_assoc(array_keys($this->manager->getDefinitions()));
+  }
+
+  /**
+   * Implements \Drupal\Component\Plugin\PluginBag::initializePlugin().
+   */
+  protected function initializePlugin($instance_id) {
+    // If the plugin was initialized before, just return.
+    if (isset($this->pluginInstances[$instance_id])) {
+      return;
+    }
+
+    $this->pluginInstances[$instance_id] = $this->manager->createInstance($instance_id, array());
+  }
+
+}

core/modules/views/lib/Drupal/views/DisplayArray.php

@@ -1,165 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\views\DisplayArray.
- */
-
-namespace Drupal\views;
-
-/**
- * A class which wraps the displays of a view so you can lazy-initialize them.
- */
-class DisplayArray implements \ArrayAccess, \Iterator, \Countable {
-
-  /**
-   * Stores a reference to the view which has this displays attached.
-   *
-   * @var \Drupal\views\ViewExecutable
-   */
-  protected $view;
-
-  /**
-   * Stores the actual display instances in an array.
-   *
-   * @var array
-   */
-  protected $displayHandlers = array();
-
-  /**
-   * Stores all display IDs, coming from $this->view->storage->get('display').
-   *
-   * @var array
-   */
-  protected $displayIDs;
-
-  /**
-   * Constructs a DisplayArray object.
-   *
-   * @param \Drupal\views\ViewExecutable
-   *   The view which has this displays attached.
-   */
-  public function __construct(ViewExecutable $view) {
-    $this->view = $view;
-
-    $this->initializeDisplay('default');
-
-    // Store all display IDs to access them easy and fast.
-    $display = $this->view->storage->get('display');
-    $this->displayIDs = drupal_map_assoc(array_keys($display));
-  }
-
-  /**
-   * Destructs a DisplayArray object.
-   */
-  public function __destruct() {
-    foreach ($this->displayHandlers as $display_id => $display) {
-      $display->destroy();
-      unset($this->displayHandlers[$display_id]);
-    }
-  }
-
-  /**
-   * Initializes a single display and stores the result in $this->displayHandlers.
-   *
-   * @param string $display_id
-   *   The name of the display to initialize.
-   */
-  protected function initializeDisplay($display_id) {
-    // If the display was initialized before, just return.
-    if (isset($this->displayHandlers[$display_id])) {
-      return;
-    }
-
-    // Retrieve and initialize the new display handler with data.
-    $display = &$this->view->storage->getDisplay($display_id);
-    $this->displayHandlers[$display_id] = drupal_container()->get("plugin.manager.views.display")->createInstance($display['display_plugin']);
-    if (empty($this->displayHandlers[$display_id])) {
-      // Provide a 'default' handler as an emergency. This won't work well but
-      // it will keep things from crashing.
-      $this->displayHandlers[$display_id] = drupal_container()->get("plugin.manager.views.display")->createInstance('default');
-    }
-
-    $this->displayHandlers[$display_id]->initDisplay($this->view, $display);
-    // If this is not the default display handler, let it know which is since
-    // it may well utilize some data from the default.
-    if ($display_id != 'default') {
-      $this->displayHandlers[$display_id]->default_display = $this->displayHandlers['default'];
-    }
-  }
-
-  /**
-   * Implements \ArrayAccess::offsetExists().
-   */
-  public function offsetExists($offset) {
-    return isset($this->displayHandlers[$offset]) || isset($this->displayIDs[$offset]);
-  }
-
-  /**
-   * Implements \ArrayAccess::offsetGet().
-   */
-  public function offsetGet($offset) {
-    if (!isset($this->displayHandlers[$offset])) {
-      $this->initializeDisplay($offset);
-    }
-    return $this->displayHandlers[$offset];
-  }
-
-  /**
-   * Implements \ArrayAccess::offsetSet().
-   */
-  public function offsetSet($offset, $value) {
-    $this->displayHandlers[$offset] = $value;
-  }
-
-  /**
-   * Implements \ArrayAccess::offsetUnset().
-   */
-  public function offsetUnset($offset) {
-    unset($this->displayHandlers[$offset]);
-  }
-
-  /**
-   * Implements \Iterator::current().
-   */
-  public function current() {
-    return $this->offsetGet($this->key());
-  }
-
-  /**
-   * Implements \Iterator::next().
-   */
-  public function next() {
-    next($this->displayIDs);
-  }
-
-  /**
-   * Implements \Iterator::key().
-   */
-  public function key() {
-    return key($this->displayIDs);
-  }
-
-  /**
-   * Implements \Iterator::valid().
-   */
-  public function valid() {
-    $key = key($this->displayIDs);
-    return $key !== NULL && $key !== FALSE;
-  }
-
-  /**
-   * Implements \Iterator::rewind().
-   */
-  public function rewind() {
-    reset($this->displayIDs);
-  }
-
-  /**
-   * Implements \Countable::count().
-   */
-  public function count() {
-    return count($this->displayIDs);
-  }
-
-}

core/modules/views/lib/Drupal/views/DisplayBag.php

@@ -0,0 +1,84 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\views\DisplayBag.
+ */
+
+namespace Drupal\views;
+
+use Drupal\Component\Plugin\PluginBag;
+
+/**
+ * A class which wraps the displays of a view so you can lazy-initialize them.
+ */
+class DisplayBag extends PluginBag {
+
+  /**
+   * Stores a reference to the view which has this displays attached.
+   *
+   * @var \Drupal\views\ViewExecutable
+   */
+  protected $view;
+
+  /**
+   * Constructs a DisplayBag object.
+   *
+   * @param \Drupal\views\ViewExecutable
+   *   The view which has this displays attached.
+   */
+  public function __construct(ViewExecutable $view) {
+    $this->view = $view;
+
+    $this->initializePlugin('default');
+
+    // Store all display IDs to access them easy and fast.
+    $display = $this->view->storage->get('display');
+    $this->instanceIDs = drupal_map_assoc(array_keys($display));
+  }
+
+  /**
+   * Destructs a DisplayBag object.
+   */
+  public function __destruct() {
+    $this->clear();
+  }
+
+  /**
+   * Overrides \Drupal\Component\Plugin\PluginBag::clear().
+   */
+  public function clear() {
+    foreach ($this->pluginInstances as $display_id => $display) {
+      $display->destroy();
+    }
+
+    parent::clear();
+  }
+
+  /**
+   * Overrides \Drupal\Component\Plugin\PluginBag::initializePlugin().
+   */
+  protected function initializePlugin($display_id) {
+    // If the display was initialized before, just return.
+    if (isset($this->pluginInstances[$display_id])) {
+      return;
+    }
+
+    // Retrieve and initialize the new display handler with data.
+    $display = &$this->view->storage->getDisplay($display_id);
+    $this->pluginInstances[$display_id] = drupal_container()->get("plugin.manager.views.display")->createInstance($display['display_plugin']);
+    if (empty($this->pluginInstances[$display_id])) {
+      // Provide a 'default' handler as an emergency. This won't work well but
+      // it will keep things from crashing.
+      $this->pluginInstances[$display_id] = drupal_container()->get("plugin.manager.views.display")->createInstance('default');
+    }
+
+    $this->pluginInstances[$display_id]->initDisplay($this->view, $display);
+    // If this is not the default display handler, let it know which is since
+    // it may well utilize some data from the default.
+    if ($display_id != 'default') {
+      $this->pluginInstances[$display_id]->default_display = $this->pluginInstances['default'];
+    }
+  }
+
+}

core/modules/views/lib/Drupal/views/Tests/ViewExecutableTest.php

@@ -9,7 +9,7 @@ namespace Drupal\views\Tests;
 
 use Symfony\Component\HttpFoundation\Response;
 use Drupal\views\ViewExecutable;
-use Drupal\views\DisplayArray;
+use Drupal\views\DisplayBag;
 use Drupal\views\Plugin\views\display\DefaultDisplay;
 use Drupal\views\Plugin\views\display\Page;
 use Drupal\views\Plugin\views\style\DefaultStyle;
@@ -152,7 +152,7 @@ class ViewExecutableTest extends ViewUnitTestBase {
 
     // Tests Drupal\views\ViewExecutable::initDisplay().
     $view->initDisplay();
-    $this->assertTrue($view->displayHandlers instanceof DisplayArray, 'The displayHandlers property has the right class.');
+    $this->assertTrue($view->displayHandlers instanceof DisplayBag, 'The displayHandlers property has the right class.');
     // Tests the classes of the instances.
     $this->assertTrue($view->displayHandlers['default'] instanceof DefaultDisplay);
     $this->assertTrue($view->displayHandlers['page_1'] instanceof Page);

core/modules/views/lib/Drupal/views/ViewExecutable.php

@@ -597,7 +597,7 @@ class ViewExecutable {
     }
 
     // Initialize the display cache array.
-    $this->displayHandlers = new DisplayArray($this);
+    $this->displayHandlers = new DisplayBag($this);
 
     $this->current_display = 'default';
     $this->display_handler = $this->displayHandlers['default'];