- Patch #443422 by yched, bjaspan | chx, merlinofchaos, Scott Reynolds, plach, profix898, mattyoung: added support for pluggable 'per field' storage engine. Comes with documentation and tests.

The Field Attach API uses the Field Storage API to perform all "database access". Each Field Storage API hook function defines a primitive database operation such as read, write, or delete. The default field storage module, field_sql_storage.module, uses the local SQL database to implement these operations, but alternative field storage backends can choose to represent the data in SQL differently or use a completely different storage mechanism such as a cloud-based database.

1 files changed, 64 insertions, 9 deletions

diff --git a/modules/field/field.info.inc b/modules/field/field.info.inc
index aa5b4d08b..8b273da6a 100644
--- a/modules/field/field.info.inc
+++ b/modules/field/field.info.inc
@@ -78,6 +78,7 @@ function _field_info_collate_types($reset = FALSE) {
         'field types' => array(),
         'widget types' => array(),
         'formatter types' => array(),
+        'storage types' => array(),
         'fieldable types' => array(),
       );
 
@@ -110,7 +111,7 @@ function _field_info_collate_types($reset = FALSE) {
       }
       drupal_alter('field_widget_info', $info['widget types']);
 
-      // Populate formatters.
+      // Populate formatter types.
       foreach (module_implements('field_formatter_info') as $module) {
         $formatter_types = (array) module_invoke($module, 'field_formatter_info');
         foreach ($formatter_types as $name => $formatter_info) {
@@ -124,6 +125,20 @@ function _field_info_collate_types($reset = FALSE) {
       }
       drupal_alter('field_formatter_info', $info['formatter types']);
 
+      // Populate storage types.
+      foreach (module_implements('field_storage_info') as $module) {
+        $storage_types = (array) module_invoke($module, 'field_storage_info');
+        foreach ($storage_types as $name => $storage_info) {
+          // Provide defaults.
+          $storage_info += array(
+            'settings' => array(),
+          );
+          $info['storage types'][$name] = $storage_info;
+          $info['storage types'][$name]['module'] = $module;
+        }
+      }
+      drupal_alter('field_storage_info', $info['storage types']);
+
       // Populate information about 'fieldable' entities.
       foreach (module_implements('entity_info') as $module) {
         $entities = (array) module_invoke($module, 'entity_info');
@@ -246,6 +261,7 @@ function _field_info_collate_fields($reset = FALSE) {
 function _field_info_prepare_field($field) {
   // Make sure all expected field settings are present.
   $field['settings'] += field_info_field_settings($field['type']);
+  $field['storage']['settings'] += field_info_storage_settings($field['storage']['type']);
 
   return $field;
 }
@@ -371,8 +387,8 @@ function field_info_field_types($field_type = NULL) {
  *   returned.
  * @return
  *   Either a widget type description, as provided by
- *   hook_field_widget_info(), or an array of all existing widget
- *   types, keyed by widget type name.
+ *   hook_field_widget_info(), or an array of all existing widget types, keyed
+ *   by widget type name.
  */
 function field_info_widget_types($widget_type = NULL) {
   $info = _field_info_collate_types();
@@ -394,8 +410,9 @@ function field_info_widget_types($widget_type = NULL) {
  *   (optional) A formatter type name. If ommitted, all formatter types will be
  *   returned.
  * @return
- *   Either a formatter type description, as provided by hook_field_formatter_info(),
- *   or an array of all existing widget types, keyed by widget type name.
+ *   Either a formatter type description, as provided by
+ *   hook_field_formatter_info(), or an array of all existing formatter types,
+ *   keyed by formatter type name.
  */
 function field_info_formatter_types($formatter_type = NULL) {
   $info = _field_info_collate_types();
@@ -411,6 +428,30 @@ function field_info_formatter_types($formatter_type = NULL) {
 }
 
 /**
+ * Return hook_field_storage_info() data.
+ *
+ * @param $storage_type
+ *   (optional) A storage type name. If ommitted, all storage types will be
+ *   returned.
+ * @return
+ *   Either a storage type description, as provided by
+ *   hook_field_storage_info(), or an array of all existing storage types,
+ *   keyed by storage type name.
+ */
+function field_info_storage_types($storage_type = NULL) {
+  $info = _field_info_collate_types();
+  $storage_types = $info['storage types'];
+  if ($storage_type) {
+    if (isset($storage_types[$storage_type])) {
+      return $storage_types[$storage_type];
+    }
+  }
+  else {
+    return $storage_types;
+  }
+}
+
+/**
  * Return hook_fieldable_info() data.
  *
  * @param $obj_type
@@ -574,8 +615,8 @@ function field_info_instance_settings($type) {
  * @param $type
  *   A widget type name.
  * @return
- *   The field type's default settings, as provided by hook_field_info(), or an
- *   empty array.
+ *   The widget type's default settings, as provided by
+ *   hook_field_widget_info(), or an empty array.
  */
 function field_info_widget_settings($type) {
   $info = field_info_widget_types($type);
@@ -588,8 +629,8 @@ function field_info_widget_settings($type) {
  * @param $type
  *   A field formatter type name.
  * @return
- *   The field formatter's default settings, as provided by
- *   hook_field_info(), or an empty array.
+ *   The formatter type's default settings, as provided by
+ *   hook_field_formatter_info(), or an empty array.
  */
 function field_info_formatter_settings($type) {
   $info = field_info_formatter_types($type);
@@ -597,5 +638,19 @@ function field_info_formatter_settings($type) {
 }
 
 /**
+ * Return a field formatter's default settings.
+ *
+ * @param $type
+ *   A field storage type name.
+ * @return
+ *   The storage type's default settings, as provided by
+ *   hook_field_storage_info(), or an empty array.
+ */
+function field_info_storage_settings($type) {
+  $info = field_info_storage_types($type);
+  return isset($info['settings']) ? $info['settings'] : array();
+}
+
+/**
  * @} End of "defgroup field_info"
  */