[gtk+: 5/8] wayland: always return FALSE from begin_paint

[Ray Strode <halfline src gnome org>]

commit 2c300081c4fc4db6a345041cbf4942cb99cea793
Author: Ray Strode <rstrode redhat com>
Date:   Tue Feb 2 12:20:22 2016 -0500

    wayland: always return FALSE from begin_paint
    
    The client and compositor share access to the window
    pixel buffers. After the client hands off (commits)
    the buffer to the compositor it's not supposed to write
    to it again until it's released by the compositor.
    
    The code tries to deal with this contention by allocating
    a temporary buffer and using that in the mean time. This
    temporary buffer is allocated by a higher layer of the code
    when begin_paint returns TRUE. Unfortunately, that layer of
    the code has no idea when the buffer is released, so it ends
    up blitting the temporary buffer back to the shared buffer
    prematurely.
    
    This commit changes begin_paint to always return FALSE.
    
    A future commit will address the contention problem in
    a different way.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=761312

 gdk/wayland/gdkdisplay-wayland.c |   19 -------------------
 gdk/wayland/gdkprivate-wayland.h |    2 --
 gdk/wayland/gdkwindow-wayland.c  |    9 +--------
 3 files changed, 1 insertions(+), 29 deletions(-)
---
diff --git a/gdk/wayland/gdkdisplay-wayland.c b/gdk/wayland/gdkdisplay-wayland.c
index fcd3502..500e211 100644
--- a/gdk/wayland/gdkdisplay-wayland.c
+++ b/gdk/wayland/gdkdisplay-wayland.c
@@ -906,7 +906,6 @@ typedef struct _GdkWaylandCairoSurfaceData {
   struct wl_buffer *buffer;
   GdkWaylandDisplay *display;
   uint32_t scale;
-  gboolean busy;
 } GdkWaylandCairoSurfaceData;
 
 static void
@@ -914,9 +913,7 @@ buffer_release_callback (void             *_data,
                          struct wl_buffer *wl_buffer)
 {
   cairo_surface_t *surface = _data;
-  GdkWaylandCairoSurfaceData *data = cairo_surface_get_user_data (surface, &gdk_wayland_cairo_key);
 
-  data->busy = FALSE;
   cairo_surface_destroy (surface);
 }
 
@@ -1001,7 +998,6 @@ _gdk_wayland_display_create_shm_surface (GdkWaylandDisplay *display,
   data->display = display;
   data->buffer = NULL;
   data->scale = scale;
-  data->busy = FALSE;
 
   stride = cairo_format_stride_for_width (CAIRO_FORMAT_ARGB32, width*scale);
 
@@ -1043,21 +1039,6 @@ _gdk_wayland_shm_surface_get_wl_buffer (cairo_surface_t *surface)
   return data->buffer;
 }
 
-void
-_gdk_wayland_shm_surface_set_busy (cairo_surface_t *surface)
-{
-  GdkWaylandCairoSurfaceData *data = cairo_surface_get_user_data (surface, &gdk_wayland_cairo_key);
-  data->busy = TRUE;
-  cairo_surface_reference (surface);
-}
-
-gboolean
-_gdk_wayland_shm_surface_get_busy (cairo_surface_t *surface)
-{
-  GdkWaylandCairoSurfaceData *data = cairo_surface_get_user_data (surface, &gdk_wayland_cairo_key);
-  return data->busy;
-}
-
 gboolean
 _gdk_wayland_is_shm_surface (cairo_surface_t *surface)
 {
diff --git a/gdk/wayland/gdkprivate-wayland.h b/gdk/wayland/gdkprivate-wayland.h
index 9e51517..123a33b 100644
--- a/gdk/wayland/gdkprivate-wayland.h
+++ b/gdk/wayland/gdkprivate-wayland.h
@@ -232,8 +232,6 @@ cairo_surface_t * _gdk_wayland_display_create_shm_surface (GdkWaylandDisplay *di
                                                            int                height,
                                                            guint              scale);
 struct wl_buffer *_gdk_wayland_shm_surface_get_wl_buffer (cairo_surface_t *surface);
-void _gdk_wayland_shm_surface_set_busy (cairo_surface_t *surface);
-gboolean _gdk_wayland_shm_surface_get_busy (cairo_surface_t *surface);
 gboolean _gdk_wayland_is_shm_surface (cairo_surface_t *surface);
 
 GdkWaylandSelection * gdk_wayland_display_get_selection (GdkDisplay *display);
diff --git a/gdk/wayland/gdkwindow-wayland.c b/gdk/wayland/gdkwindow-wayland.c
index f5a0546..1c509e5 100644
--- a/gdk/wayland/gdkwindow-wayland.c
+++ b/gdk/wayland/gdkwindow-wayland.c
@@ -442,8 +442,6 @@ on_frame_clock_after_paint (GdkFrameClock *clock,
   _gdk_frame_clock_freeze (clock);
 
   wl_surface_commit (impl->display_server.wl_surface);
-  if (_gdk_wayland_is_shm_surface (impl->cairo_surface))
-    _gdk_wayland_shm_surface_set_busy (impl->cairo_surface);
 
   g_signal_emit (impl, signals[COMMITTED], 0);
 }
@@ -641,14 +639,9 @@ gdk_wayland_window_create_similar_image_surface (GdkWindow *     window,
 static gboolean
 gdk_window_impl_wayland_begin_paint (GdkWindow *window)
 {
-  GdkWindowImplWayland *impl = GDK_WINDOW_IMPL_WAYLAND (window->impl);
-
   gdk_wayland_window_ensure_cairo_surface (window);
 
-  if (_gdk_wayland_is_shm_surface (impl->cairo_surface))
-    return _gdk_wayland_shm_surface_get_busy (impl->cairo_surface);
-  else
-    return FALSE;
+  return FALSE;
 }
 
 static void