Support for limiting editing of attributes

Content controllers is a new feature for controlling which
attributes can be edited by the current user.
Each content controller is called when fetching input for an
attribute and may deny access to editing that attribute.

A content controller is defined by adding the class name to
EditSettings/ContentControllers in content.ini. If no controllers
are defined then all attributes are allowed as before.
The class must then implement the `canEditAttribute` method
which accepts the object attribute as the first parameter.

kernel/classes/ezcontentobject.php

@@ -2413,6 +2413,38 @@ function commitInputRelations( $editVersion )
         return true;
     }
 
+    /**
+     * Returns a list of content controller instances.
+     * A content controller can help limit access to certain attributes.
+     * 
+     * Controllers are defined in content.ini, EditSettings/ContentControlls
+     * and are cached in a global variable.
+     *
+     * @return object[]
+     */
+    public static function getContentControllers()
+    {
+        if ( isset( $GLOBALS['EZP_CONTENT_CONTROLLERS'] ) )
+        {
+            return $GLOBALS['EZP_CONTENT_CONTROLLERS'];
+        }
+
+        $contentControllers = array();
+        $contentIni = eZINI::instance('content.ini');
+        if ( $contentIni->hasVariable( 'EditSettings', 'ContentControllers' ) )
+        {
+            $contentControllerNames = $contentIni->variable( 'EditSettings', 'ContentControllers' );
+            foreach ($contentControllerNames as $contentControllerName)
+            {
+                $controller = new $contentControllerName();
+                $contentControllers[] = $controller;
+            }
+        }
+        $GLOBALS['EZP_CONTENT_CONTROLLERS'] = $contentControllers;
+
+        return $contentControllers;
+    }
+
     /**
      * @param eZContentObjectAttribute[] $contentObjectAttributes
      * @param string $attributeDataBaseName
@@ -2447,6 +2479,8 @@ function validateInput( $contentObjectAttributes, $attributeDataBaseName,
 
         $this->resetInputRelationList();
 
+        $contentControllers = self::getContentControllers();
+
         $editVersion = null;
         $defaultLanguage = $this->initialLanguageCode();
         foreach( $contentObjectAttributes as $contentObjectAttribute )
@@ -2471,6 +2505,16 @@ function validateInput( $contentObjectAttributes, $attributeDataBaseName,
                     $doNotValidate = true;
             }
 
+            // Check if attribute access is denied from custom controllers
+            foreach ($contentControllers as $contentController)
+            {
+                if ( !$contentController->canEditAttribute( $contentObjectAttribute ) )
+                {
+                    $doNotValidate = true;
+                    break;
+                }
+            }
+
             if ( $doNotValidate == true )
             {
                 $status = eZInputValidator::STATE_ACCEPTED;
@@ -2575,6 +2619,8 @@ function fetchInput( $contentObjectAttributes, $attributeDataBaseName,
 
         $defaultLanguage = $this->initialLanguageCode();
 
+        $contentControllers = self::getContentControllers();
+
         $this->fetchDataMap();
         foreach ( $contentObjectAttributes as $contentObjectAttribute )
         {
@@ -2597,6 +2643,16 @@ function fetchInput( $contentObjectAttributes, $attributeDataBaseName,
                 }
             }
 
+            // Check if attribute access is denied from custom controllers
+            foreach ($contentControllers as $contentController)
+            {
+                if ( !$contentController->canEditAttribute( $contentObjectAttribute ) )
+                {
+                    $fetchInput = false;
+                    break;
+                }
+            }
+
             // Do not handle input for non-translateable attributes.
             // Input will be copyed from the std. translation on storage
             if ( $fetchInput )