Revert "remove dataengine stuff"

This reverts commit 0b57f5164da376afbb86b9ac915960ee7dc5693a.

svn path=/trunk/KDE/kdelibs/; revision=1012646

contextaction.cpp

@@ -20,6 +20,7 @@
 #include "contextaction.h"
 #include "containment.h"
 
+#include "private/dataengineconsumer_p.h"
 #include "private/packages_p.h"
 #include "private/contextaction_p.h"
 #include "private/containment_p.h"
@@ -206,6 +207,11 @@ QList<QAction*> ContextAction::contextualActions()
     return QList<QAction*>();
 }
 
+DataEngine *ContextAction::dataEngine(const QString &name) const
+{
+    return d->dataEngine(name);
+}
+
 bool ContextAction::configurationRequired() const
 {
     return d->needsConfig;

contextaction.h

@@ -33,6 +33,7 @@ class QAction;
 namespace Plasma
 {
 
+class DataEngine;
 class Containment;
 class ContextActionPrivate;
 
@@ -171,6 +172,26 @@ class PLASMA_EXPORT ContextAction : public QObject
          */
         virtual QList<QAction*> contextualActions();
 
+        /**
+         * Loads the given DataEngine
+         *
+         * Tries to load the data engine given by @p name.  Each engine is
+         * only loaded once, and that instance is re-used on all subsequent
+         * requests.
+         *
+         * If the data engine was not found, an invalid data engine is returned
+         * (see DataEngine::isValid()).
+         *
+         * Note that you should <em>not</em> delete the returned engine.
+         *
+         * @param name Name of the data engine to load
+         * @return pointer to the data engine if it was loaded,
+         *         or an invalid data engine if the requested engine
+         *         could not be loaded
+         *
+         */
+        Q_INVOKABLE DataEngine *dataEngine(const QString &name) const;
+
         /**
          * @return true if the contextaction currently needs to be configured,
          *         otherwise, false