[mutter] wayland: get rid of buffer->copied_data boolean

[Ray Strode <halfline src gnome org>]

commit e097bc8353f70fb47d5b2b40d2a7b12c7fc29855
Author: Ray Strode <rstrode redhat com>
Date:   Mon Feb 8 16:07:34 2016 -0500

    wayland: get rid of buffer->copied_data boolean
    
    We currently track whether or not a buffer can be released early
    by looking at the copied_data boolean on the buffer.  This boolean
    is, practically speaking, always set to TRUE for shm buffers and is
    always false otherwise.
    
    We can just as easily check if the buffer is a shm buffer to decide
    whether or not to do an early release.  That's better from a
    theoretical point of view since copied_data assumes a 1-to-1
    relationship between surface and buffer, which may not actually hold.
    
    This commit drops copied_data and changes the check to instead see
    if the buffer is shm.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=761613

 src/wayland/meta-wayland-buffer.c  |    3 ---
 src/wayland/meta-wayland-buffer.h  |    1 -
 src/wayland/meta-wayland-surface.c |   11 ++++++++++-
 3 files changed, 10 insertions(+), 5 deletions(-)
---
diff --git a/src/wayland/meta-wayland-buffer.c b/src/wayland/meta-wayland-buffer.c
index 1d9b0c3..bb0e8d2 100644
--- a/src/wayland/meta-wayland-buffer.c
+++ b/src/wayland/meta-wayland-buffer.c
@@ -140,9 +140,6 @@ meta_wayland_buffer_ensure_texture (MetaWaylandBuffer *buffer)
 
   buffer->texture = texture;
 
-  if (shm_buffer)
-    buffer->copied_data = TRUE;
-
  out:
   return buffer->texture;
 }
diff --git a/src/wayland/meta-wayland-buffer.h b/src/wayland/meta-wayland-buffer.h
index 22cbcc1..9f6a5bf 100644
--- a/src/wayland/meta-wayland-buffer.h
+++ b/src/wayland/meta-wayland-buffer.h
@@ -41,7 +41,6 @@ struct _MetaWaylandBuffer
   uint32_t ref_count;
 
   uint32_t accessible : 1;
-  uint32_t copied_data : 1;
 };
 
 MetaWaylandBuffer *     meta_wayland_buffer_from_resource       (struct wl_resource    *resource);
diff --git a/src/wayland/meta-wayland-surface.c b/src/wayland/meta-wayland-surface.c
index aa98246..fc884d9 100644
--- a/src/wayland/meta-wayland-surface.c
+++ b/src/wayland/meta-wayland-surface.c
@@ -648,6 +648,8 @@ static void
 apply_pending_state (MetaWaylandSurface      *surface,
                      MetaWaylandPendingState *pending)
 {
+  gboolean release_new_buffer = FALSE;
+
   if (pending->newly_attached)
     {
       if (!surface->buffer && surface->window)
@@ -657,9 +659,16 @@ apply_pending_state (MetaWaylandSurface      *surface,
 
       if (pending->buffer)
         {
+          struct wl_shm_buffer *shm_buffer = wl_shm_buffer_get (pending->buffer->resource);
+
           meta_wayland_buffer_take_control (pending->buffer);
           CoglTexture *texture = meta_wayland_buffer_ensure_texture (pending->buffer);
           meta_surface_actor_wayland_set_texture (META_SURFACE_ACTOR_WAYLAND (surface->surface_actor), 
texture);
+
+          /* Release the buffer as soon as possible, so the client can reuse it
+          */
+          if (shm_buffer)
+            release_new_buffer = TRUE;
         }
     }
 
@@ -669,7 +678,7 @@ apply_pending_state (MetaWaylandSurface      *surface,
   if (!cairo_region_is_empty (pending->damage))
     surface_process_damage (surface, pending->damage);
 
-  if (pending->buffer && pending->buffer->copied_data)
+  if (release_new_buffer)
     meta_wayland_buffer_release_control (pending->buffer);
 
   surface->offset_x += pending->dx;