[mutter/wip/carlosg/grabs-pt1: 91/93] clutter: Integrate ClutterSeat grabs into ClutterGrab

[Carlos Garnacho <carlosg src gnome org>]

commit 9d9750b9020703c9b3af5d0eb7622bdf96fd23a7
Author: Carlos Garnacho <carlosg gnome org>
Date:   Thu Oct 28 17:05:44 2021 +0200

    clutter: Integrate ClutterSeat grabs into ClutterGrab
    
    As ClutterGrab is a stack, the backend only cares about some grab
    existing currently or not. Make it sure that we grab whenever we
    go to >=1 grabs, and ungrab whenever we go to <1.

 clutter/clutter/clutter-grab.h  |  3 +++
 clutter/clutter/clutter-stage.c | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)
---
diff --git a/clutter/clutter/clutter-grab.h b/clutter/clutter/clutter-grab.h
index 8c87046496..5cb86baa57 100644
--- a/clutter/clutter/clutter-grab.h
+++ b/clutter/clutter/clutter-grab.h
@@ -35,4 +35,7 @@ typedef struct _ClutterGrab ClutterGrab;
 CLUTTER_EXPORT
 void clutter_grab_dismiss (ClutterGrab *grab);
 
+CLUTTER_EXPORT
+ClutterGrabState clutter_grab_get_windowing_state (ClutterGrab *grab);
+
 #endif /* CLUTTER_GRAB_H */
diff --git a/clutter/clutter/clutter-stage.c b/clutter/clutter/clutter-stage.c
index 7a67ae05e1..6559059e06 100644
--- a/clutter/clutter/clutter-stage.c
+++ b/clutter/clutter/clutter-stage.c
@@ -62,6 +62,7 @@
 #include "clutter-paint-volume-private.h"
 #include "clutter-pick-context-private.h"
 #include "clutter-private.h"
+#include "clutter-seat-private.h"
 #include "clutter-stage-manager-private.h"
 #include "clutter-stage-private.h"
 #include "clutter-stage-view-private.h"
@@ -115,6 +116,7 @@ struct _ClutterStagePrivate
   ClutterActor *key_focused_actor;
 
   ClutterGrab *grabs;
+  ClutterGrabState grab_state;
 
   GQueue *event_queue;
 
@@ -3857,6 +3859,18 @@ clutter_stage_grab (ClutterStage *stage,
   g_return_val_if_fail (CLUTTER_IS_STAGE (stage), NULL);
   g_return_val_if_fail (CLUTTER_IS_ACTOR (actor), NULL);
 
+  if (!priv->grabs)
+    {
+      ClutterMainContext *context;
+      ClutterSeat *seat;
+
+      /* First grab in the chain, trigger a backend grab too */
+      context = _clutter_context_get_default ();
+      seat = clutter_backend_get_default_seat (context->backend);
+      priv->grab_state =
+        clutter_seat_grab (seat, clutter_get_current_event_time ());
+    }
+
   grab = g_new0 (ClutterGrab, 1);
   grab->stage = stage;
   grab->actor = actor;
@@ -3901,6 +3915,18 @@ clutter_stage_unlink_grab (ClutterStage *stage,
 
   clutter_actor_detach_grab (grab->actor, grab);
 
+  if (!priv->grabs)
+    {
+      ClutterMainContext *context;
+      ClutterSeat *seat;
+
+      /* This was the last remaining grab, trigger a backend ungrab */
+      context = _clutter_context_get_default ();
+      seat = clutter_backend_get_default_seat (context->backend);
+      clutter_seat_ungrab (seat, clutter_get_current_event_time ());
+      priv->grab_state = CLUTTER_GRAB_STATE_NONE;
+    }
+
   grab->next = NULL;
   grab->prev = NULL;
 }
@@ -3914,6 +3940,14 @@ clutter_grab_dismiss (ClutterGrab *grab)
   g_free (grab);
 }
 
+ClutterGrabState
+clutter_grab_get_windowing_state (ClutterGrab *grab)
+{
+  g_return_val_if_fail (grab != NULL, CLUTTER_GRAB_STATE_NONE);
+
+  return grab->stage->priv->grab_state;
+}
+
 ClutterActor *
 clutter_stage_get_grab_actor (ClutterStage *stage)
 {