Check for protocol errors before converting dnd actions

It kind of makes more sense to check for errors and then start doing
the actual work.

src/wayland/dataoffer_interface.cpp

@@ -82,21 +82,14 @@ void DataOfferInterfacePrivate::data_offer_finish(Resource *resource)
 void DataOfferInterfacePrivate::data_offer_set_actions(Resource *resource, uint32_t dnd_actions, uint32_t preferred_action)
 {
     // TODO: check it's drag and drop, otherwise send error
-    DataDeviceManagerInterface::DnDActions supportedActions;
-    if (dnd_actions & QtWaylandServer::wl_data_device_manager::dnd_action_copy) {
-        supportedActions |= DataDeviceManagerInterface::DnDAction::Copy;
-    }
-    if (dnd_actions & QtWaylandServer::wl_data_device_manager::dnd_action_move) {
-        supportedActions |= DataDeviceManagerInterface::DnDAction::Move;
-    }
-    if (dnd_actions & QtWaylandServer::wl_data_device_manager::dnd_action_ask) {
-        supportedActions |= DataDeviceManagerInterface::DnDAction::Ask;
-    }
     // verify that the no other actions are sent
-    if (dnd_actions & ~(QtWaylandServer::wl_data_device_manager::dnd_action_copy | QtWaylandServer::wl_data_device_manager::dnd_action_move | QtWaylandServer::wl_data_device_manager::dnd_action_ask)) {
+    if (dnd_actions & ~(QtWaylandServer::wl_data_device_manager::dnd_action_copy |
+                        QtWaylandServer::wl_data_device_manager::dnd_action_move |
+                        QtWaylandServer::wl_data_device_manager::dnd_action_ask)) {
         wl_resource_post_error(resource->handle, error_invalid_action_mask, "Invalid action mask");
         return;
     }
+
     if (preferred_action != QtWaylandServer::wl_data_device_manager::dnd_action_copy &&
         preferred_action != QtWaylandServer::wl_data_device_manager::dnd_action_move &&
         preferred_action != QtWaylandServer::wl_data_device_manager::dnd_action_ask &&
@@ -105,6 +98,17 @@ void DataOfferInterfacePrivate::data_offer_set_actions(Resource *resource, uint3
         return;
     }
 
+    DataDeviceManagerInterface::DnDActions supportedActions;
+    if (dnd_actions & QtWaylandServer::wl_data_device_manager::dnd_action_copy) {
+        supportedActions |= DataDeviceManagerInterface::DnDAction::Copy;
+    }
+    if (dnd_actions & QtWaylandServer::wl_data_device_manager::dnd_action_move) {
+        supportedActions |= DataDeviceManagerInterface::DnDAction::Move;
+    }
+    if (dnd_actions & QtWaylandServer::wl_data_device_manager::dnd_action_ask) {
+        supportedActions |= DataDeviceManagerInterface::DnDAction::Ask;
+    }
+
     DataDeviceManagerInterface::DnDAction preferredAction = DataDeviceManagerInterface::DnDAction::None;
     if (preferred_action == QtWaylandServer::wl_data_device_manager::dnd_action_copy) {
         preferredAction = DataDeviceManagerInterface::DnDAction::Copy;

src/wayland/datasource_interface.cpp

@@ -70,6 +70,13 @@ void DataSourceInterfacePrivate::offer(const QString &mimeType)
 
 void DataSourceInterfacePrivate::data_source_set_actions(Resource *resource, uint32_t dnd_actions)
 {
+    // verify that the no other actions are sent
+    if (dnd_actions & ~(QtWaylandServer::wl_data_device_manager::dnd_action_copy |
+                        QtWaylandServer::wl_data_device_manager::dnd_action_move |
+                        QtWaylandServer::wl_data_device_manager::dnd_action_ask)) {
+        wl_resource_post_error(resource->handle, error_invalid_action_mask, "Invalid action mask");
+        return;
+    }
     DataDeviceManagerInterface::DnDActions supportedActions;
     if (dnd_actions & QtWaylandServer::wl_data_device_manager::dnd_action_copy) {
         supportedActions |= DataDeviceManagerInterface::DnDAction::Copy;
@@ -80,11 +87,6 @@ void DataSourceInterfacePrivate::data_source_set_actions(Resource *resource, uin
     if (dnd_actions & QtWaylandServer::wl_data_device_manager::dnd_action_ask) {
         supportedActions |= DataDeviceManagerInterface::DnDAction::Ask;
     }
-    // verify that the no other actions are sent
-    if (dnd_actions & ~(QtWaylandServer::wl_data_device_manager::dnd_action_copy | QtWaylandServer::wl_data_device_manager::dnd_action_move | QtWaylandServer::wl_data_device_manager::dnd_action_ask)) {
-        wl_resource_post_error(resource->handle, QtWaylandServer::wl_data_source::error_invalid_action_mask, "Invalid action mask");
-        return;
-    }
     if (supportedDnDActions!= supportedActions) {
         supportedDnDActions = supportedActions;
         emit q->supportedDragAndDropActionsChanged();