Drupal 8.0.0 beta 12. More info: https://www.drupal.org/node/2514176

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

@@ -0,0 +1,145 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Component\Plugin\ContextAwarePluginBase.
+ */
+
+namespace Drupal\Component\Plugin;
+
+use Drupal\Component\Plugin\Context\ContextInterface;
+use Drupal\Component\Plugin\Exception\ContextException;
+use Drupal\Component\Plugin\Context\Context;
+use Symfony\Component\Validator\ConstraintViolationList;
+
+/**
+ * Base class for plugins that are context aware.
+ */
+abstract class ContextAwarePluginBase extends PluginBase implements ContextAwarePluginInterface {
+
+  /**
+   * The data objects representing the context of this plugin.
+   *
+   * @var \Drupal\Component\Plugin\Context\ContextInterface[]
+   */
+  protected $context;
+
+  /**
+   * Overrides \Drupal\Component\Plugin\PluginBase::__construct().
+   *
+   * Overrides the construction of context aware plugins to allow for
+   * unvalidated constructor based injection of contexts.
+   *
+   * @param array $configuration
+   *   The plugin configuration, i.e. an array with configuration values keyed
+   *   by configuration option name. The special key 'context' may be used to
+   *   initialize the defined contexts by setting it to an array of context
+   *   values keyed by context names.
+   * @param string $plugin_id
+   *   The plugin_id for the plugin instance.
+   * @param mixed $plugin_definition
+   *   The plugin implementation definition.
+   */
+  public function __construct(array $configuration, $plugin_id, $plugin_definition) {
+    $context = array();
+    if (isset($configuration['context'])) {
+      $context = $configuration['context'];
+      unset($configuration['context']);
+    }
+    parent::__construct($configuration, $plugin_id, $plugin_definition);
+    foreach ($context as $key => $value) {
+      $context_definition = $this->getContextDefinition($key);
+      $this->context[$key] = new Context($context_definition);
+      $this->context[$key]->setContextValue($value);
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getContextDefinitions() {
+    $definition = $this->getPluginDefinition();
+    return !empty($definition['context']) ? $definition['context'] : array();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getContextDefinition($name) {
+    $definition = $this->getPluginDefinition();
+    if (empty($definition['context'][$name])) {
+      throw new ContextException(sprintf("The %s context is not a valid context.", $name));
+    }
+    return $definition['context'][$name];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getContexts() {
+    // Make sure all context objects are initialized.
+    foreach ($this->getContextDefinitions() as $name => $definition) {
+      $this->getContext($name);
+    }
+    return $this->context;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getContext($name) {
+    // Check for a valid context value.
+    if (!isset($this->context[$name])) {
+      $this->context[$name] = new Context($this->getContextDefinition($name));
+    }
+    return $this->context[$name];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setContext($name, ContextInterface $context) {
+    $this->context[$name] = $context;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getContextValues() {
+    $values = array();
+    foreach ($this->getContextDefinitions() as $name => $definition) {
+      $values[$name] = isset($this->context[$name]) ? $this->context[$name]->getContextValue() : NULL;
+    }
+    return $values;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getContextValue($name) {
+    return $this->getContext($name)->getContextValue();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setContextValue($name, $value) {
+    $this->getContext($name)->setContextValue($value);
+    return $this;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateContexts() {
+    $violations = new ConstraintViolationList();
+    // @todo: Implement symfony validator API to let the validator traverse
+    // and set property paths accordingly.
+
+    foreach ($this->getContexts() as $context) {
+      $violations->addAll($context->validate());
+    }
+    return $violations;
+  }
+
+}