[mutter] wayland: Always realize buffers at surface commit time

[Jonas Ådahl <jadahl src gnome org>]

commit 22723ca37173955d8ef4c6981795e91a85f4feb9
Author: Miguel A. Vico <mvicomoya nvidia com>
Date:   Fri May 5 18:41:51 2017 -0700

    wayland: Always realize buffers at surface commit time
    
    Clients using EGLStream-backed buffers will expect the stream to be
    functional after wl_surface::attach(). That means the compositor-side
    stream must be created and a consumer attached to it.
    
    To resolve the above, this change realizes buffers even when the attach
    operation is deferred (e.g. synchronized subsurfaces).
    
    https://bugzilla.gnome.org/show_bug.cgi?id=782575

 src/wayland/meta-wayland-buffer.c  | 21 +++++++++------------
 src/wayland/meta-wayland-buffer.h  |  2 ++
 src/wayland/meta-wayland-surface.c |  4 ++++
 3 files changed, 15 insertions(+), 12 deletions(-)
---
diff --git a/src/wayland/meta-wayland-buffer.c b/src/wayland/meta-wayland-buffer.c
index 3396f450c..b4b1e7825 100644
--- a/src/wayland/meta-wayland-buffer.c
+++ b/src/wayland/meta-wayland-buffer.c
@@ -94,13 +94,13 @@ meta_wayland_buffer_get_resource (MetaWaylandBuffer *buffer)
   return buffer->resource;
 }
 
-static gboolean
+gboolean
 meta_wayland_buffer_is_realized (MetaWaylandBuffer *buffer)
 {
   return buffer->type != META_WAYLAND_BUFFER_TYPE_UNKNOWN;
 }
 
-static gboolean
+gboolean
 meta_wayland_buffer_realize (MetaWaylandBuffer *buffer)
 {
   EGLint format;
@@ -131,13 +131,12 @@ meta_wayland_buffer_realize (MetaWaylandBuffer *buffer)
     {
       CoglTexture2D *texture;
 
-      buffer->egl_stream.stream = stream;
-      buffer->type = META_WAYLAND_BUFFER_TYPE_EGL_STREAM;
-
       texture = meta_wayland_egl_stream_create_texture (stream, NULL);
       if (!texture)
         return FALSE;
 
+      buffer->egl_stream.stream = stream;
+      buffer->type = META_WAYLAND_BUFFER_TYPE_EGL_STREAM;
       buffer->texture = COGL_TEXTURE (texture);
       buffer->is_y_inverted = meta_wayland_egl_stream_is_y_inverted (stream);
 
@@ -344,13 +343,11 @@ meta_wayland_buffer_attach (MetaWaylandBuffer *buffer,
 
   if (!meta_wayland_buffer_is_realized (buffer))
     {
-      if (!meta_wayland_buffer_realize (buffer))
-        {
-          g_set_error (error, G_IO_ERROR,
-                       G_IO_ERROR_FAILED,
-                       "Unknown buffer type");
-          return FALSE;
-        }
+      /* The buffer should have been realized at surface commit time */
+      g_set_error (error, G_IO_ERROR,
+                   G_IO_ERROR_FAILED,
+                   "Unknown buffer type");
+      return FALSE;
     }
 
   switch (buffer->type)
diff --git a/src/wayland/meta-wayland-buffer.h b/src/wayland/meta-wayland-buffer.h
index e00a41e09..036f9d428 100644
--- a/src/wayland/meta-wayland-buffer.h
+++ b/src/wayland/meta-wayland-buffer.h
@@ -69,6 +69,8 @@ G_DECLARE_FINAL_TYPE (MetaWaylandBuffer, meta_wayland_buffer,
 
 MetaWaylandBuffer *     meta_wayland_buffer_from_resource       (struct wl_resource    *resource);
 struct wl_resource *    meta_wayland_buffer_get_resource        (MetaWaylandBuffer     *buffer);
+gboolean                meta_wayland_buffer_is_realized         (MetaWaylandBuffer     *buffer);
+gboolean                meta_wayland_buffer_realize             (MetaWaylandBuffer     *buffer);
 gboolean                meta_wayland_buffer_attach              (MetaWaylandBuffer     *buffer,
                                                                  GError               **error);
 CoglTexture *           meta_wayland_buffer_get_texture         (MetaWaylandBuffer     *buffer);
diff --git a/src/wayland/meta-wayland-surface.c b/src/wayland/meta-wayland-surface.c
index 0142e1a3d..6160da692 100644
--- a/src/wayland/meta-wayland-surface.c
+++ b/src/wayland/meta-wayland-surface.c
@@ -752,6 +752,10 @@ cleanup:
 static void
 meta_wayland_surface_commit (MetaWaylandSurface *surface)
 {
+  if (surface->pending->buffer &&
+      !meta_wayland_buffer_is_realized (surface->pending->buffer))
+    meta_wayland_buffer_realize (surface->pending->buffer);
+
   /*
    * If this is a sub-surface and it is in effective synchronous mode, only
    * cache the pending surface state until either one of the following two