display: Move finishing of touch sequence to the backend

We need to manipulate an X11 grab when a touch sequence ends; move that
logic to where it belongs - in the X11 backend.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/886

src/backends/meta-backend-private.h

@@ -51,6 +51,14 @@
 #define META_TYPE_BACKEND (meta_backend_get_type ())
 G_DECLARE_DERIVABLE_TYPE (MetaBackend, meta_backend, META, BACKEND, GObject)
 
+typedef enum _MetaSequenceState
+{
+  META_SEQUENCE_NONE,
+  META_SEQUENCE_ACCEPTED,
+  META_SEQUENCE_REJECTED,
+  META_SEQUENCE_PENDING_END
+} MetaSequenceState;
+
 struct _MetaBackendClass
 {
   GObjectClass parent_class;
@@ -73,6 +81,10 @@ struct _MetaBackendClass
                               int          device_id,
                               uint32_t     timestamp);
 
+  void (* finish_touch_sequence) (MetaBackend          *backend,
+                                  ClutterEventSequence *sequence,
+                                  MetaSequenceState     state);
+
   void (* warp_pointer) (MetaBackend *backend,
                          int          x,
                          int          y);
@@ -134,6 +146,10 @@ gboolean meta_backend_ungrab_device (MetaBackend *backend,
                                      int          device_id,
                                      uint32_t     timestamp);
 
+void meta_backend_finish_touch_sequence (MetaBackend          *backend,
+                                         ClutterEventSequence *sequence,
+                                         MetaSequenceState     state);
+
 void meta_backend_warp_pointer (MetaBackend *backend,
                                 int          x,
                                 int          y);

src/backends/meta-backend.c

@@ -846,6 +846,20 @@ meta_backend_ungrab_device (MetaBackend *backend,
   return META_BACKEND_GET_CLASS (backend)->ungrab_device (backend, device_id, timestamp);
 }
 
+/**
+ * meta_backend_finish_touch_sequence: (skip)
+ */
+void
+meta_backend_finish_touch_sequence (MetaBackend          *backend,
+                                    ClutterEventSequence *sequence,
+                                    MetaSequenceState     state)
+{
+  if (META_BACKEND_GET_CLASS (backend)->finish_touch_sequence)
+    META_BACKEND_GET_CLASS (backend)->finish_touch_sequence (backend,
+                                                             sequence,
+                                                             state);
+}
+
 /**
  * meta_backend_warp_pointer: (skip)
  */

src/backends/x11/meta-backend-x11.c

@@ -584,6 +584,28 @@ meta_backend_x11_ungrab_device (MetaBackend *backend,
   return (ret == Success);
 }
 
+static void
+meta_backend_x11_finish_touch_sequence (MetaBackend          *backend,
+                                        ClutterEventSequence *sequence,
+                                        MetaSequenceState     state)
+{
+  MetaBackendX11 *x11 = META_BACKEND_X11 (backend);
+  MetaBackendX11Private *priv = meta_backend_x11_get_instance_private (x11);
+  int event_mode;
+
+  if (state == META_SEQUENCE_ACCEPTED)
+    event_mode = XIAcceptTouch;
+  else if (state == META_SEQUENCE_REJECTED)
+    event_mode = XIRejectTouch;
+  else
+    g_return_if_reached ();
+
+  XIAllowTouchEvents (priv->xdisplay,
+                      META_VIRTUAL_CORE_POINTER_ID,
+                      clutter_x11_event_sequence_get_touch_detail (sequence),
+                      DefaultRootWindow (priv->xdisplay), event_mode);
+}
+
 static void
 meta_backend_x11_warp_pointer (MetaBackend *backend,
                                int          x,
@@ -769,6 +791,7 @@ meta_backend_x11_class_init (MetaBackendX11Class *klass)
   backend_class->post_init = meta_backend_x11_post_init;
   backend_class->grab_device = meta_backend_x11_grab_device;
   backend_class->ungrab_device = meta_backend_x11_ungrab_device;
+  backend_class->finish_touch_sequence = meta_backend_x11_finish_touch_sequence;
   backend_class->warp_pointer = meta_backend_x11_warp_pointer;
   backend_class->get_current_logical_monitor = meta_backend_x11_get_current_logical_monitor;
   backend_class->get_keymap = meta_backend_x11_get_keymap;

src/core/display.c

@@ -55,6 +55,7 @@
 #include "backends/x11/meta-backend-x11.h"
 #include "backends/meta-stage-private.h"
 #include "backends/meta-input-settings-private.h"
+#include "backends/meta-backend-private.h"
 #include <clutter/x11/clutter-x11.h>
 
 #ifdef HAVE_RANDR
@@ -533,27 +534,23 @@ gesture_tracker_state_changed (MetaGestureTracker   *tracker,
                                MetaSequenceState     state,
                                MetaDisplay          *display)
 {
-  if (meta_is_wayland_compositor ())
+  switch (state)
     {
-      if (state == META_SEQUENCE_ACCEPTED)
+    case META_SEQUENCE_NONE:
-        meta_display_cancel_touch (display);
+    case META_SEQUENCE_PENDING_END:
-    }
-  else
-    {
-      MetaBackendX11 *backend = META_BACKEND_X11 (meta_get_backend ());
-      int event_mode;
-
-      if (state == META_SEQUENCE_ACCEPTED)
-        event_mode = XIAcceptTouch;
-      else if (state == META_SEQUENCE_REJECTED)
-        event_mode = XIRejectTouch;
-      else
       return;
+    case META_SEQUENCE_ACCEPTED:
+      meta_display_cancel_touch (display);
 
-      XIAllowTouchEvents (meta_backend_x11_get_xdisplay (backend),
+      /* Intentional fall-through */
-                          META_VIRTUAL_CORE_POINTER_ID,
+    case META_SEQUENCE_REJECTED:
-                          clutter_x11_event_sequence_get_touch_detail (sequence),
+      {
-                          DefaultRootWindow (display->xdisplay), event_mode);
+        MetaBackend *backend;
+
+        backend = meta_get_backend ();
+        meta_backend_finish_touch_sequence (backend, sequence, state);
+        break;
+      }
     }
 }
 

src/core/meta-gesture-tracker-private.h

@@ -38,12 +38,7 @@
 typedef struct _MetaGestureTracker MetaGestureTracker;
 typedef struct _MetaGestureTrackerClass MetaGestureTrackerClass;
 
-typedef enum {
+typedef enum _MetaSequenceState MetaSequenceState;
-  META_SEQUENCE_NONE,
-  META_SEQUENCE_ACCEPTED,
-  META_SEQUENCE_REJECTED,
-  META_SEQUENCE_PENDING_END
-} MetaSequenceState;
 
 struct _MetaGestureTracker
 {

src/core/meta-gesture-tracker.c

@@ -31,6 +31,7 @@
 #include "config.h"
 #include "meta-gesture-tracker-private.h"
 #include "meta-surface-actor.h"
+#include "meta-backend-private.h"
 
 #define DISTANCE_THRESHOLD 30