Issue #1743686 by EclipseGc, fago, amateescu, damiankloip: Added Condition Plugin System.

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

@@ -8,6 +8,8 @@
 namespace Drupal\Component\Plugin\Context;
 
 use Drupal\Component\Plugin\Exception\ContextException;
+use Symfony\Component\Validator\Constraints\Type;
+use Symfony\Component\Validator\Validation;
 
 /**
  * A generic context class for wrapping data a plugin needs to operate.
@@ -39,7 +41,6 @@ public function __construct(array $context_definition) {
    * Implements \Drupal\Component\Plugin\Context\ContextInterface::setContextValue().
    */
   public function setContextValue($value) {
-    $value = $this->validate($value);
     $this->contextValue = $value;
   }
 
@@ -65,22 +66,22 @@ public function getContextDefinition() {
   }
 
   /**
-   * Implements \Drupal\Component\Plugin\Context\ContextInterface::validate().
-   *
-   * The default validation method only supports instance of checks between the
-   * contextDefintion and the contextValue. Other formats of context
-   * definitions can be supported through a subclass.
+   * Implements \Drupal\Component\Plugin\Context\ContextInterface::getConstraints().
    */
-  public function validate($value) {
-    // Check to make sure we have a class name, and that the passed context is
-    // an instance of that class name.
-    if (!empty($this->contextDefinition['class'])) {
-      if ($value instanceof $this->contextDefinition['class']) {
-        return $value;
-      }
-      throw new ContextException("The context passed was not an instance of {$this->contextDefinition['class']}.");
+  public function getConstraints() {
+    if (empty($this->contextDefinition['class'])) {
+      throw new ContextException("An error was encountered while trying to validate the context.");
     }
-    throw new ContextException("An error was encountered while trying to validate the context.");
+    return array(new Type($this->contextDefinition['class']));
+  }
+
+  /**
+   * Implements \Drupal\Component\Plugin\Context\ContextInterface::validate().
+   */
+  public function validate() {
+    $validator = Validation::createValidatorBuilder()
+      ->getValidator();
+    return $validator->validateValue($this->getContextValue(), $this->getConstraints());
   }
 
 }

core/lib/Drupal/Component/Plugin/Context/ContextInterface.php

@@ -7,8 +7,6 @@
 
 namespace Drupal\Component\Plugin\Context;
 
-use Drupal\Component\Plugin\Exception\ContextException;
-
 /**
  * A generic context interface for wrapping data a plugin needs to operate.
  */
@@ -18,8 +16,9 @@ interface ContextInterface {
    * Sets the context value.
    *
    * @param mixed $value
-   *   The value of this context, generally an object based upon the class
-   *   matching the definition passed to setContextDefinition().
+   *   The value of this context, matching the context definition.
+   *
+   * @see \Drupal\Component\Plugin\Context\ContextInterface::setContextDefinition().
    */
   public function setContextValue($value);
 
@@ -27,42 +26,45 @@ public function setContextValue($value);
    * Gets the context value.
    *
    * @return mixed
-   *   The currently set context value within this class.
+   *   The currently set context value, or NULL if it is not set.
    */
   public function getContextValue();
 
   /**
    * Sets the definition that the context must conform to.
    *
-   * @param mixed $contextDefinition
+   * @param array $contextDefinition
    *   A defining characteristic representation of the context against which
-   *   that context can be validated. This is typically a class name, but could
-   *   be extended to support other validation notation.
+   *   that context can be validated. This is typically an array having a
+   *   class name set under the 'class' key, but it could be extended to support
+   *   other notations.
    */
   public function setContextDefinition(array $contextDefinition);
 
   /**
    * Gets the provided definition that the context must conform to.
    *
-   * @return mixed
+   * @return array
    *   The defining characteristic representation of the context.
    */
   public function getContextDefinition();
 
   /**
-   * Validate the provided context value against the provided definition.
-   *
-   * @param mixed $value
-   *   The context value that should be validated against the context
-   *   definition.
+   * Gets a list of validation constraints.
    *
-   * @return mixed
-   *   Returns the context value passed to it. If it fails validation, an
-   *   exception will be thrown.
+   * @return array
+   *   Array of constraints, each being an instance of
+   *   \Symfony\Component\Validator\Constraint.
+   */
+  public function getConstraints();
+
+  /**
+   * Validates the set context value.
    *
-   * @throws \Drupal\Component\Plugin\Exception\ContextException
-   *   If validation fails.
+   * @return \Symfony\Component\Validator\ConstraintViolationListInterface
+   *   A list of constraint violations. If the list is empty, validation
+   *   succeeded.
    */
-  public function validate($value);
+  public function validate();
 
 }

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

@@ -9,6 +9,8 @@
 
 use Drupal\Component\Plugin\Exception\PluginException;
 use Drupal\Component\Plugin\Context\Context;
+use Symfony\Component\Validator\ConstraintViolationList;
+use Drupal\Component\Plugin\Discovery\DiscoveryInterface;
 
 /**
  * Base class for plugins that are context aware.
@@ -22,23 +24,49 @@ abstract class ContextAwarePluginBase extends PluginBase implements ContextAware
    */
   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.
+   */
+  public function __construct(array $configuration, $plugin_id, DiscoveryInterface $discovery) {
+    $context = array();
+    if (isset($configuration['context'])) {
+      $context = $configuration['context'];
+      unset($configuration['context']);
+    }
+    parent::__construct($configuration, $plugin_id, $discovery);
+    foreach ($context as $key => $value) {
+      $context_definition = $this->getContextDefinition($key);
+      $this->context[$key] = new Context($context_definition);
+      $this->context[$key]->setContextValue($value);
+    }
+  }
+
   /**
    * Implements \Drupal\Component\Plugin\ContextAwarePluginInterface::getContextDefinitions().
    */
   public function getContextDefinitions() {
     $definition = $this->getDefinition();
-    return !empty($definition['context']) ? $definition['context'] : NULL;
+    return !empty($definition['context']) ? $definition['context'] : array();
   }
 
   /**
    * Implements \Drupal\Component\Plugin\ContextAwarePluginInterface::getContextDefinition().
    */
-  public function getContextDefinition($key) {
+  public function getContextDefinition($name) {
     $definition = $this->getDefinition();
-    if (empty($definition['context'][$key])) {
-      throw new PluginException("The $key context is not a valid context.");
+    if (empty($definition['context'][$name])) {
+      throw new PluginException("The $name context is not a valid context.");
     }
-    return $definition['context'][$key];
+    return $definition['context'][$name];
   }
 
   /**
@@ -46,19 +74,15 @@ public function getContextDefinition($key) {
    */
   public function getContexts() {
     $definitions = $this->getContextDefinitions();
-    // If there are no contexts defined by the plugin, return an empty array.
-    if (empty($definitions)) {
-      return array();
-    }
-    if (empty($this->context)) {
+    if ($definitions && empty($this->context)) {
       throw new PluginException("There are no set contexts.");
     }
     $contexts = array();
-    foreach (array_keys($definitions) as $key) {
-      if (empty($this->context[$key])) {
-        throw new PluginException("The $key context is not yet set.");
+    foreach (array_keys($definitions) as $name) {
+      if (empty($this->context[$name])) {
+        throw new PluginException("The $name context is not yet set.");
       }
-      $contexts[$key] = $this->context[$key];
+      $contexts[$name] = $this->context[$name];
     }
     return $contexts;
   }
@@ -66,44 +90,67 @@ public function getContexts() {
   /**
    * Implements \Drupal\Component\Plugin\ContextAwarePluginInterface::getContext().
    */
-  public function getContext($key) {
+  public function getContext($name) {
     // Check for a valid context definition.
-    $this->getContextDefinition($key);
+    $this->getContextDefinition($name);
     // Check for a valid context value.
-    if (empty($this->context[$key])) {
-      throw new PluginException("The $key context is not yet set.");
+    if (!isset($this->context[$name])) {
+      throw new PluginException("The $name context is not yet set.");
     }
 
-    return $this->context[$key];
+    return $this->context[$name];
   }
 
   /**
    * Implements \Drupal\Component\Plugin\ContextAwarePluginInterface::getContextValues().
    */
   public function getContextValues() {
-    $contexts = array();
-    foreach ($this->getContexts() as $key => $context) {
-      $contexts[$key] = $context->getContextValue();
+    $values = array();
+    foreach ($this->getContextDefinitions() as $name => $definition) {
+      $values[$name] = isset($this->context[$name]) ? $this->context[$name]->getContextValue() : NULL;
     }
-    return $contexts;
+    return $values;
   }
 
   /**
    * Implements \Drupal\Component\Plugin\ContextAwarePluginInterface::getContextValue().
    */
-  public function getContextValue($key) {
-    return $this->getContext($key)->getContextValue();
+  public function getContextValue($name) {
+    return $this->getContext($name)->getContextValue();
   }
 
   /**
    * Implements \Drupal\Component\Plugin\ContextAwarePluginInterface::setContextValue().
    */
-  public function setContextValue($key, $value) {
-    $context_definition = $this->getContextDefinition($key);
-    $this->context[$key] = new Context($context_definition);
-    $this->context[$key]->setContextValue($value);
+  public function setContextValue($name, $value) {
+    $context_definition = $this->getContextDefinition($name);
+    $this->context[$name] = new Context($context_definition);
+    $this->context[$name]->setContextValue($value);
 
+    // Verify the provided value validates.
+    $violations = $this->context[$name]->validate();
+    if (count($violations) > 0) {
+      throw new PluginException("The provided context value does not pass validation.");
+    }
     return $this;
   }
 
+  /**
+   * Implements \Drupal\Component\Plugin\ContextAwarePluginInterface::valdidateContexts().
+   */
+  public function validateContexts() {
+    $violations = new ConstraintViolationList();
+    // @todo: Implement symfony validator API to let the validator traverse
+    // and set property paths accordingly.
+
+    foreach ($this->getContextDefinitions() as $name => $definition) {
+      // Validate any set values.
+      if (isset($this->context[$name])) {
+        $violations->addAll($this->context[$name]->validate());
+      }
+      // @todo: If no value is set, make sure any mapping is validated.
+    }
+    return $violations;
+  }
+
 }

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

@@ -8,35 +8,43 @@
 namespace Drupal\Component\Plugin;
 
 use Drupal\Component\Plugin\Exception\PluginException;
-use Drupal\Component\Plugin\Context\Context;
 
 /**
  * Interface for defining context aware plugins.
+ *
+ * Context aware plugins can specify an array of context definitions keyed by
+ * context name at the plugin definition under the "context" key.
  */
 interface ContextAwarePluginInterface extends PluginInspectionInterface {
 
   /**
    * Gets the context definitions of the plugin.
    *
-   * @return array|null
-   *   The context definitions if set, otherwise NULL.
+   * @return array
+   *   The array of context definitions, keyed by context name.
    */
   public function getContextDefinitions();
 
   /**
-   * Gets the a specific context definition of the plugin.
+   * Gets a specific context definition of the plugin.
    *
-   * @param string $key
+   * @param string $name
    *   The name of the context in the plugin definition.
    *
-   * @return mixed
+   * @throws \Drupal\Component\Plugin\Exception\PluginException
+   *   If the requested context is not defined.
+   *
+   * @return array
    *   The definition against which the context value must validate.
    */
-  public function getContextDefinition($key);
+  public function getContextDefinition($name);
 
   /**
    * Gets the defined contexts.
    *
+   * @throws \Drupal\Component\Plugin\Exception\PluginException
+   *   If contexts are defined but not set.
+   *
    * @return array
    *   The set context objects.
    */
@@ -45,47 +53,64 @@ public function getContexts();
   /**
    * Gets a defined context.
    *
-   * @param string $key
-   *   The name of the context in the plugin configuration. This string is
-   *   usually identical to the representative string in the plugin definition.
+   * @param string $name
+   *   The name of the context in the plugin definition.
+   *
+   * @throws \Drupal\Component\Plugin\Exception\PluginException
+   *   If the requested context is not set.
    *
    * @return \Drupal\Component\Plugin\Context\ContextInterface
    *   The context object.
    */
-  public function getContext($key);
+  public function getContext($name);
 
   /**
    * Gets the values for all defined contexts.
    *
    * @return array
-   *   The set context object values.
+   *   An array of set context values, keyed by context name. If a context is
+   *   unset its value is returned as NULL.
    */
   public function getContextValues();
 
   /**
    * Gets the value for a defined context.
    *
-   * @param string $key
-   *   The name of the context in the plugin configuration. This string is
-   *   usually identical to the representative string in the plugin definition.
+   * @param string $name
+   *   The name of the context in the plugin configuration.
+   *
+   * @throws \Drupal\Component\Plugin\Exception\PluginException
+   *   If the requested context is not set.
    *
    * @return mixed
    *   The currently set context value.
    */
-  public function getContextValue($key);
+  public function getContextValue($name);
 
   /**
    * Sets the value for a defined context.
    *
-   * @param string $key
+   * @param string $name
    *   The name of the context in the plugin definition.
    * @param mixed $value
-   *   The variable to set the context to. This should validate against the
+   *   The value to set the context to. The value has to validate against the
    *   provided context definition.
    *
+   * @throws \Drupal\Component\Plugin\Exception\PluginException
+   *   If the value does not pass validation.
+   *
    * @return \Drupal\Component\Plugin\ContextAwarePluginInterface.
    *   A context aware plugin object for chaining.
    */
-  public function setContextValue($key, $value);
+  public function setContextValue($name, $value);
+
+  /**
+   * Validates the set values for the defined contexts.
+   *
+   * @return \Symfony\Component\Validator\ConstraintViolationListInterface
+   *   A list of constraint violations. If the list is empty, validation
+   *   succeeded.
+   */
+  public function validateContexts();
 
 }

core/lib/Drupal/Core/Condition/ConditionInterface.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Condition\ConditionInterface.
+ */
+
+namespace Drupal\Core\Condition;
+
+use Drupal\Core\Executable\ExecutableInterface;
+
+/**
+ * An interface for condition plugins.
+ *
+ * @see \Drupal\Core\Executable\ExecutableInterface
+ */
+interface ConditionInterface extends ExecutableInterface {
+
+  /**
+   * Determines whether condition result will be negated.
+   *
+   * @return boolean
+   *   Whether the condition result will be negated.
+   */
+  public function isNegated();
+
+  /**
+   * Evaluates the condition and returns TRUE or FALSE accordingly.
+   *
+   * @return bool
+   *   TRUE if the condition has been met, FALSE otherwise.
+   */
+  public function evaluate();
+
+}

core/lib/Drupal/Core/Condition/ConditionManager.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Condition\ConditionManager.
+ */
+
+namespace Drupal\Core\Condition;
+
+use Drupal\Component\Plugin\PluginManagerBase;
+use Drupal\Core\Executable\ExecutableManagerInterface;
+use Drupal\Core\Executable\ExecutableInterface;
+use Drupal\Component\Plugin\Factory\DefaultFactory;
+use Drupal\Component\Plugin\Discovery\DerivativeDiscoveryDecorator;
+use Drupal\Core\Plugin\Discovery\AlterDecorator;
+use Drupal\Core\Plugin\Discovery\AnnotatedClassDiscovery;
+use Drupal\Core\Plugin\Discovery\CacheDecorator;
+
+/**
+ * A plugin manager for condition plugins.
+ */
+class ConditionManager extends PluginManagerBase implements ExecutableManagerInterface {
+
+  /**
+   * Constructs aa ConditionManager object.
+   */
+  public function __construct() {
+    $this->discovery = new AnnotatedClassDiscovery('Core', 'Condition');
+    $this->discovery = new DerivativeDiscoveryDecorator($this->discovery);
+    $this->discovery = new AlterDecorator($this->discovery, 'condition_info');
+    $this->discovery = new CacheDecorator($this->discovery, 'condition:' . language(LANGUAGE_TYPE_INTERFACE)->langcode);
+
+    $this->factory = new DefaultFactory($this);
+  }
+
+  /**
+   * Override of Drupal\Component\Plugin\PluginManagerBase::createInstance().
+   */
+  public function createInstance($plugin_id, array $configuration = array()) {
+    $plugin = $this->factory->createInstance($plugin_id, $configuration);
+    return $plugin->setExecutableManager($this);
+  }
+
+  /**
+   * Implements Drupal\Core\Executable\ExecutableManagerInterface::execute().
+   */
+  public function execute(ExecutableInterface $condition) {
+    $result = $condition->evaluate();
+    return $condition->isNegated() ? !$result : $result;
+  }
+
+}

core/lib/Drupal/Core/Condition/ConditionPluginBase.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Condition\ConditionPluginBase.
+ */
+
+namespace Drupal\Core\Condition;
+
+use Drupal\Core\Executable\ExecutablePluginBase;
+
+/**
+ * Provides a basis for fulfilling contexts for condition plugins.
+ */
+abstract class ConditionPluginBase extends ExecutablePluginBase implements ConditionInterface {
+
+  /**
+   * Implements \Drupal\Core\Form\FormInterface::getFormID().
+   */
+  public function getFormID() {
+    $definition = $this->getDefinition();
+    return implode('_', array($definition['module'], $definition['id'], 'condition'));
+  }
+
+  /**
+   * Implements \Drupal\condition\Plugin\ConditionInterface::isNegated().
+   */
+  public function isNegated() {
+    return !empty($this->configuration['negate']);
+  }
+
+  /**
+   * Implements \Drupal\Core\Form\FormInterface::buildForm().
+   */
+  public function buildForm(array $form, array &$form_state) {
+    $form['negate'] = array(
+      '#type' => 'checkbox',
+      '#title' => t('Negate the condition.'),
+      '#default_value' => isset($this->configuration['negate']) ? $this->configuration['negate'] : FALSE,
+    );
+    return $form;
+  }
+
+  /**
+   * Implements \Drupal\Core\Form\FormInterface::validateForm().
+   */
+  public function validateForm(array &$form, array &$form_state) {}
+
+  /**
+   * Implements \Drupal\Core\Form\FormInterface::submitForm().
+   */
+  public function submitForm(array &$form, array &$form_state) {
+    $this->configuration['negate'] = $form_state['values']['negate'];
+  }
+
+  /**
+   * Implements \Drupal\Core\Executable\ExecutablePluginBase::execute().
+   */
+  public function execute() {
+    return $this->executableManager->execute($this);
+  }
+
+}

core/lib/Drupal/Core/CoreBundle.php

@@ -276,6 +276,8 @@ public function build(ContainerBuilder $container) {
     $container->register('flood', 'Drupal\Core\Flood\DatabaseBackend')
       ->addArgument(new Reference('database'));
 
+    $container->register('plugin.manager.condition', 'Drupal\Core\Condition\ConditionManager');
+
     $container->addCompilerPass(new RegisterMatchersPass());
     $container->addCompilerPass(new RegisterRouteFiltersPass());
     // Add a compiler pass for registering event subscribers.

core/lib/Drupal/Core/Executable/ExecutableException.php

+<?php
+/**
+ * @file