commit c7beb2344753de06e47afb76fa053640325d1204
Author: fago <nuppla@zites.net>
Date:   Mon Dec 30 14:28:41 2013 +0100

    Added definition factory.

diff --git a/core/lib/Drupal/Core/Entity/Entity.php b/core/lib/Drupal/Core/Entity/Entity.php
index b0b905d..4f12e9b 100644
--- a/core/lib/Drupal/Core/Entity/Entity.php
+++ b/core/lib/Drupal/Core/Entity/Entity.php
@@ -45,6 +45,14 @@
   protected $routeProvider;
 
   /**
+   * {@inheritdoc}
+   */
+  public static function createDataDefinition($data_type) {
+    // @todo: Implement a proper data definition class for entities.
+    return DataDefinition::create($data_type);
+  }
+
+  /**
    * Constructs an Entity object.
    *
    * @param array $values
diff --git a/core/lib/Drupal/Core/Field/FieldItemBase.php b/core/lib/Drupal/Core/Field/FieldItemBase.php
index 37ffa55..cec6d6e 100644
--- a/core/lib/Drupal/Core/Field/FieldItemBase.php
+++ b/core/lib/Drupal/Core/Field/FieldItemBase.php
@@ -26,6 +26,16 @@
   /**
    * {@inheritdoc}
    */
+  public static function createDataDefinition($data_type) {
+    // The data type of a field item is in the form of "field_item:$field_type".
+    $parts = explode(':', $data_type, 2);
+    $field_definition = FieldDefinition::create($parts[1]);
+    return $field_definition->getItemDefinition();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
   public static function getMainPropertyName() {
     return 'value';
   }
diff --git a/core/lib/Drupal/Core/Field/FieldItemList.php b/core/lib/Drupal/Core/Field/FieldItemList.php
index 1af3254..17c1664 100644
--- a/core/lib/Drupal/Core/Field/FieldItemList.php
+++ b/core/lib/Drupal/Core/Field/FieldItemList.php
@@ -41,6 +41,15 @@ class FieldItemList extends ItemList implements FieldItemListInterface {
   /**
    * {@inheritdoc}
    */
+  public static function createDataDefinition($data_type) {
+    // The data type of a field item is in the form of "field_item:$field_type".
+    $parts = explode(':', $data_type, 2);
+    return FieldDefinition::create($parts[1]);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
   public function __construct(DataDefinitionInterface $definition, $name = NULL, TypedDataInterface $parent = NULL) {
     parent::__construct($definition, $name, $parent);
     // Always initialize one empty item as most times a value for at least one
diff --git a/core/lib/Drupal/Core/TypedData/DataDefinitionInterface.php b/core/lib/Drupal/Core/TypedData/DataDefinitionInterface.php
index e026fe8..d5eaf14 100644
--- a/core/lib/Drupal/Core/TypedData/DataDefinitionInterface.php
+++ b/core/lib/Drupal/Core/TypedData/DataDefinitionInterface.php
@@ -14,7 +14,13 @@
  * For example, a plugin could describe its parameters using data definitions
  * in order to specify what kind of data is required for it.
  *
+ * Definitions that describe lists or complex data have to implement the
+ * respective interfaces, such that the metadata about contained list items or
+ * properties can be retrieved from the definition.
+ *
  * @see \Drupal\Core\TypedData\DataDefinition
+ * @see \Drupal\Core\TypedData\ListDefinitionInterface
+ * @see \Drupal\Core\TypedData\ComplexDataDefinitionInterface
  */
 interface DataDefinitionInterface {
 
diff --git a/core/lib/Drupal/Core/TypedData/ListDefinitionInterface.php b/core/lib/Drupal/Core/TypedData/ListDefinitionInterface.php
index c07d60e..613c1f8 100644
--- a/core/lib/Drupal/Core/TypedData/ListDefinitionInterface.php
+++ b/core/lib/Drupal/Core/TypedData/ListDefinitionInterface.php
@@ -12,6 +12,8 @@
  *
  * This interface is present on a data definition if it describes a list. The
  * actual lists implement the \Drupal\Core\TypedData\ListInterface.
+ *
+ * @see \Drupal\Core\TypedData\ListDefinition
  */
 interface ListDefinitionInterface extends DataDefinitionInterface {
 
diff --git a/core/lib/Drupal/Core/TypedData/ListInterface.php b/core/lib/Drupal/Core/TypedData/ListInterface.php
index 53f5eac..d60eb64 100644
--- a/core/lib/Drupal/Core/TypedData/ListInterface.php
+++ b/core/lib/Drupal/Core/TypedData/ListInterface.php
@@ -19,6 +19,17 @@
 interface ListInterface extends TypedDataInterface, \ArrayAccess, \Countable, \Traversable {
 
   /**
+   * Creates a new list definition.
+   *
+   * @param string $data_type
+   *   The data type of the list items.
+   *
+   * @return \Drupal\Core\TypedData\ListDefinitionInterface
+   *   A list definition for the given data type.
+   */
+  public static function createDataDefinition($data_type);
+
+  /**
    * Determines whether the list contains any non-empty items.
    *
    * @return boolean
diff --git a/core/lib/Drupal/Core/TypedData/MapDefinition.php b/core/lib/Drupal/Core/TypedData/MapDefinition.php
index f3f968b..d848211 100644
--- a/core/lib/Drupal/Core/TypedData/MapDefinition.php
+++ b/core/lib/Drupal/Core/TypedData/MapDefinition.php
@@ -20,6 +20,20 @@ class MapDefinition extends ComplexDataDefinitionBase {
   protected $mainPropertyName = NULL;
 
   /**
+   * Creates a new map definition.
+   *
+   * @param string $type
+   *   (optional) The data type of the map. Defaults to 'map'.
+   *
+   * @return static
+   *   A new MapDefinition object.
+   */
+  public static function create($type = 'map') {
+    $definition['type'] = $type;
+    return new static($definition);
+  }
+
+  /**
    * {@inheritdoc}
    */
   public function getPropertyDefinitions() {
diff --git a/core/lib/Drupal/Core/TypedData/Plugin/DataType/ItemList.php b/core/lib/Drupal/Core/TypedData/Plugin/DataType/ItemList.php
index 2e906d0..91865dd 100644
--- a/core/lib/Drupal/Core/TypedData/Plugin/DataType/ItemList.php
+++ b/core/lib/Drupal/Core/TypedData/Plugin/DataType/ItemList.php
@@ -8,6 +8,7 @@
 namespace Drupal\Core\TypedData\Plugin\DataType;
 
 use Drupal\Core\TypedData\ComplexDataInterface;
+use Drupal\Core\TypedData\ListDefinition;
 use Drupal\Core\TypedData\ListInterface;
 use Drupal\Core\TypedData\TypedData;
 use Drupal\Core\TypedData\TypedDataInterface;
@@ -35,6 +36,13 @@ class ItemList extends TypedData implements \IteratorAggregate, ListInterface {
   protected $list = array();
 
   /**
+   * {@inheritdoc}
+   */
+  public static function createDataDefinition($data_type) {
+    return ListDefinition::create($data_type);
+  }
+
+  /**
    * Overrides \Drupal\Core\TypedData\TypedData::getValue().
    */
   public function getValue() {
diff --git a/core/lib/Drupal/Core/TypedData/Plugin/DataType/Map.php b/core/lib/Drupal/Core/TypedData/Plugin/DataType/Map.php
index ef5c370..d08f237 100644
--- a/core/lib/Drupal/Core/TypedData/Plugin/DataType/Map.php
+++ b/core/lib/Drupal/Core/TypedData/Plugin/DataType/Map.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\Core\TypedData\Plugin\DataType;
 
+use Drupal\Core\TypedData\MapDefinition;
 use Drupal\Core\TypedData\TypedData;
 use Drupal\Core\TypedData\ComplexDataInterface;
 
@@ -51,6 +52,13 @@ class Map extends TypedData implements \IteratorAggregate, ComplexDataInterface
   /**
    * {@inheritdoc}
    */
+  public static function createDataDefinition($data_type) {
+    return MapDefinition::create($data_type);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
   public function getPropertyDefinitions() {
     return $this->definition->getPropertyDefinitions();
   }
diff --git a/core/lib/Drupal/Core/TypedData/TypedData.php b/core/lib/Drupal/Core/TypedData/TypedData.php
index 1597c93..2dda8d2 100644
--- a/core/lib/Drupal/Core/TypedData/TypedData.php
+++ b/core/lib/Drupal/Core/TypedData/TypedData.php
@@ -39,6 +39,13 @@
   protected $parent;
 
   /**
+   * {@inheritdoc}
+   */
+  public static function createDataDefinition($data_type) {
+    return DataDefinition::create($data_type);
+  }
+
+  /**
    * Constructs a TypedData object given its definition and context.
    *
    * @param \Drupal\Core\TypedData\DataDefinitionInterface $definition
diff --git a/core/lib/Drupal/Core/TypedData/TypedDataInterface.php b/core/lib/Drupal/Core/TypedData/TypedDataInterface.php
index 4d7b066..bcd7be9 100644
--- a/core/lib/Drupal/Core/TypedData/TypedDataInterface.php
+++ b/core/lib/Drupal/Core/TypedData/TypedDataInterface.php
@@ -15,6 +15,17 @@
 interface TypedDataInterface {
 
   /**
+   * Creates a new data definition object.
+   *
+   * @param string $data_type
+   *   The data type, for which a data definition should be created.
+   *
+   * @return \Drupal\Core\TypedData\DataDefinitionInterface
+   *   A data definition for the given data type.
+   */
+  public static function createDataDefinition($data_type);
+
+  /**
    * Gets the data definition.
    *
    * @return \Drupal\Core\TypedData\DataDefinitionInterface
diff --git a/core/lib/Drupal/Core/TypedData/TypedDataManager.php b/core/lib/Drupal/Core/TypedData/TypedDataManager.php
index e060cd3..3bd17c7 100644
--- a/core/lib/Drupal/Core/TypedData/TypedDataManager.php
+++ b/core/lib/Drupal/Core/TypedData/TypedDataManager.php
@@ -133,6 +133,33 @@ public function create(DataDefinitionInterface $definition, $value = NULL, $name
   }
 
   /**
+   * Creates a new data definition object.
+   *
+   * @param string $data_type
+   *   The data type, for which a data definition should be created.
+   * @param bool $list
+   *   (optional) Whether to define a single item of the given type (FALSE), or
+   *   a list of items (TRUE). Defaults to FALSE.
+   *
+   * @return \Drupal\Core\TypedData\DataDefinitionInterface|\Drupal\Core\TypedData\ListDefinitionInterface
+   *   A data or list definition for the given data type.
+   */
+  public function createDataDefinition($data_type, $list = FALSE) {
+    $type_definition = $this->getDefinition($data_type);
+    if (!isset($type_definition)) {
+      throw new \InvalidArgumentException(format_string('Invalid data type %plugin_id has been given.', array('%plugin_id' => $data_type)));
+    }
+    // A single 'list' item is the same as a list of 'any' items. Always handle
+    // it as the latter, such that the "list" class can always act as a list.
+    if ($data_type == 'list' && !$list) {
+      $data_type = 'any';
+      $list = TRUE;
+    }
+    $class = $list ? $type_definition['list_class'] : $type_definition['class'];
+    return $class::createDataDefinition($data_type);
+  }
+
+  /**
    * Implements \Drupal\Component\Plugin\PluginManagerInterface::getInstance().
    *
    * @param array $options
diff --git a/core/modules/system/lib/Drupal/system/Tests/TypedData/MetadataTest.php b/core/modules/system/lib/Drupal/system/Tests/TypedData/MetadataTest.php
index 0ccda3a..22d81bb 100644
--- a/core/modules/system/lib/Drupal/system/Tests/TypedData/MetadataTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/TypedData/MetadataTest.php
@@ -52,20 +52,25 @@ public function setUp() {
   /**
    * Tests deriving metadata about list items.
    */
-  public function testListMetadata() {
-    // @todo: Add a definition factory to the typed data manager.
+  public function testLists() {
     $list = ListDefinition::create('string');
     $this->assertTrue($list instanceof ListDefinitionInterface);
     $item = $list->getItemDefinition();
     $this->assertTrue($item instanceof DataDefinitionInterface);
     $this->assertEqual($item->getDataType(), 'string');
+
+    // Test using the definition factory.
+    $list2 = $this->typedDataManager->createDataDefinition('list');
+    $this->assertTrue($list2 instanceof ListDefinitionInterface);
+    $list2->getItemDefinition()->setDataType('string');
+    $this->assertEqual($list, $list2);
   }
 
   /**
    * Tests deriving metadata about maps.
    */
-  public function testTypedDataMaps() {
-    $map = MapDefinition::create('map')
+  public function testMaps() {
+    $map = MapDefinition::create()
       ->setPropertyDefinition('one', DataDefinition::create('string'))
       ->setPropertyDefinition('two', DataDefinition::create('string'))
       ->setPropertyDefinition('three', DataDefinition::create('string'));
@@ -77,6 +82,14 @@ public function testTypedDataMaps() {
     $this->assertEqual($map->getPropertyDefinition('one')->getDataType(), 'string');
     $this->assertNull($map->getMainPropertyName());
     $this->assertNull($map->getPropertyDefinition('invalid'));
+
+    // Test using the definition factory.
+    $map2 = $this->typedDataManager->createDataDefinition('map');
+    $this->assertTrue($map2 instanceof ComplexDataDefinitionInterface);
+    $map2->setPropertyDefinition('one', DataDefinition::create('string'))
+      ->setPropertyDefinition('two', DataDefinition::create('string'))
+      ->setPropertyDefinition('three', DataDefinition::create('string'));
+    $this->assertEqual($map, $map2);
   }
 
   /**
@@ -104,6 +117,19 @@ public function testFields() {
     $this->assertEqual($field->getPropertyDefinition('value')->getDataType(), 'integer');
     $this->assertEqual($field->getMainPropertyName(), 'value');
     $this->assertNull($field->getPropertyDefinition('invalid'));
+
+    // Test using the definition factory for field item lists and field items.
+    $field_item2 = $this->typedDataManager->createDataDefinition('field_item:integer');
+    $this->assertFalse($field_item2 instanceof ListDefinitionInterface);
+    $this->assertTrue($field_item2 instanceof ComplexDataDefinitionInterface);
+    // Comparison should ignore the internal static cache, so compare the
+    // serialized objects instead.
+    $this->assertEqual(serialize($field_item), serialize($field_item2));
+
+    $field2 = $this->typedDataManager->createDataDefinition('field_item:integer', TRUE);
+    $this->assertTrue($field2 instanceof ListDefinitionInterface);
+    $this->assertFalse($field2 instanceof ComplexDataDefinitionInterface);
+    $this->assertEqual(serialize($field), serialize($field2));
   }
 
   /**