[mutter] data-device: Store the current drag grab

[Jasper St. Pierre <jstpierre src gnome org>]

commit 18db5d0799d045b75f76a0f0ac99ec0fc9ef03ef
Author: Carlos Garnacho <carlosg gnome org>
Date:   Fri Sep 26 19:08:42 2014 +0200

    data-device: Store the current drag grab
    
    And bail out if any further start_drag() is attempted.

 src/wayland/meta-wayland-data-device.c |   11 +++++++----
 src/wayland/meta-wayland-data-device.h |    3 +++
 2 files changed, 10 insertions(+), 4 deletions(-)
---
diff --git a/src/wayland/meta-wayland-data-device.c b/src/wayland/meta-wayland-data-device.c
index 60d1c8c..ed2e4f8 100644
--- a/src/wayland/meta-wayland-data-device.c
+++ b/src/wayland/meta-wayland-data-device.c
@@ -162,7 +162,7 @@ static struct wl_data_source_interface data_source_interface = {
   data_source_destroy
 };
 
-typedef struct {
+struct _MetaWaylandDragGrab {
   MetaWaylandPointerGrab  generic;
 
   MetaWaylandSeat        *seat;
@@ -177,7 +177,7 @@ typedef struct {
 
   MetaWaylandDataSource  *drag_data_source;
   struct wl_listener      drag_data_source_listener;
-} MetaWaylandDragGrab;
+};
 
 static void
 destroy_drag_focus (struct wl_listener *listener, void *data)
@@ -271,6 +271,8 @@ data_device_end_drag_grab (MetaWaylandDragGrab *drag_grab)
   if (drag_grab->drag_data_source)
     wl_list_remove (&drag_grab->drag_data_source_listener.link);
 
+  drag_grab->seat->data_device.current_grab = NULL;
+
   drag_grab_focus (&drag_grab->generic, NULL);
 
   meta_wayland_pointer_end_grab (drag_grab->generic.pointer);
@@ -339,10 +341,11 @@ data_device_start_drag (struct wl_client *client,
 
   /* FIXME: Check that the data source type array isn't empty. */
 
-  if (seat->pointer.grab != &seat->pointer.default_grab)
+  if (data_device->current_grab ||
+      seat->pointer.grab != &seat->pointer.default_grab)
     return;
 
-  drag_grab = g_slice_new0 (MetaWaylandDragGrab);
+  data_device->current_grab = drag_grab = g_slice_new0 (MetaWaylandDragGrab);
 
   drag_grab->generic.interface = &drag_grab_interface;
   drag_grab->generic.pointer = &seat->pointer;
diff --git a/src/wayland/meta-wayland-data-device.h b/src/wayland/meta-wayland-data-device.h
index 931346c..854c1fd 100644
--- a/src/wayland/meta-wayland-data-device.h
+++ b/src/wayland/meta-wayland-data-device.h
@@ -27,12 +27,15 @@
 
 #include "meta-wayland-types.h"
 
+typedef struct _MetaWaylandDragGrab MetaWaylandDragGrab;
+
 struct _MetaWaylandDataDevice
 {
   uint32_t selection_serial;
   MetaWaylandDataSource *selection_data_source;
   struct wl_listener selection_data_source_listener;
   struct wl_list resource_list;
+  MetaWaylandDragGrab *current_grab;
 };
 
 void meta_wayland_data_device_manager_init (MetaWaylandCompositor *compositor);