[gnome-shell] st: Init framebuffer early to fix gnome-shell crash on NVIDIA drivers

[Martin Szulecki <mszulecki src gnome org>]

commit 5226d8b0864fa894f180b8584e837aaf565578b2
Author: Martin Szulecki <martin szulecki libimobiledevice org>
Date:   Tue May 17 15:00:04 2016 +0200

    st: Init framebuffer early to fix gnome-shell crash on NVIDIA drivers
    
    Checking offscreen for COGL_INVALID_HANDLE is not sufficient,
    as cogl_offscreen_new_with_texture doesn't initialize framebuffer
    objects but lets Cogl solve this the lazy way.
    cogl_offscreen_new_with_texture will never return COGL_INVALID_HANDLE
    anyways.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=764898

 src/st/st-theme-node-drawing.c    |   18 ++++++++++++------
 src/st/st-theme-node-transition.c |   25 ++++++++++++++++++++-----
 2 files changed, 32 insertions(+), 11 deletions(-)
---
diff --git a/src/st/st-theme-node-drawing.c b/src/st/st-theme-node-drawing.c
index 85feb20..8942966 100644
--- a/src/st/st-theme-node-drawing.c
+++ b/src/st/st-theme-node-drawing.c
@@ -2224,6 +2224,7 @@ st_theme_node_prerender_shadow (StThemeNodePaintState *state)
   int max_borders[4];
   int center_radius, corner_id;
   CoglHandle buffer, offscreen = COGL_INVALID_HANDLE;
+  CoglError *error = NULL;
 
   /* Get infos from the node */
   if (state->alloc_width < node->box_shadow_min_width ||
@@ -2264,10 +2265,12 @@ st_theme_node_prerender_shadow (StThemeNodePaintState *state)
                                        state->box_shadow_height,
                                        COGL_TEXTURE_NO_SLICING,
                                        COGL_PIXEL_FORMAT_ANY);
-  if (buffer != COGL_INVALID_HANDLE)
-    offscreen = cogl_offscreen_new_with_texture (buffer);
+  if (buffer == NULL)
+    return;
 
-  if (offscreen != COGL_INVALID_HANDLE)
+  offscreen = cogl_offscreen_new_with_texture (buffer);
+
+  if (cogl_framebuffer_allocate (COGL_FRAMEBUFFER (offscreen), &error))
     {
       ClutterActorBox box = { 0, 0, state->box_shadow_width, state->box_shadow_height};
 
@@ -2277,14 +2280,17 @@ st_theme_node_prerender_shadow (StThemeNodePaintState *state)
       cogl_framebuffer_clear4f (offscreen, COGL_BUFFER_BIT_COLOR, 0, 0, 0, 0);
 
       st_theme_node_paint_borders (state, offscreen, &box, 0xFF);
-      cogl_handle_unref (offscreen);
 
       state->box_shadow_pipeline = _st_create_shadow_pipeline (st_theme_node_get_box_shadow (node),
                                                                buffer);
     }
+  else
+    {
+      cogl_error_free (error);
+    }
 
-  if (buffer != COGL_INVALID_HANDLE)
-    cogl_handle_unref (buffer);
+  cogl_handle_unref (offscreen);
+  cogl_handle_unref (buffer);
 }
 
 static void
diff --git a/src/st/st-theme-node-transition.c b/src/st/st-theme-node-transition.c
index 1eef17b..afde977 100644
--- a/src/st/st-theme-node-transition.c
+++ b/src/st/st-theme-node-transition.c
@@ -241,6 +241,7 @@ setup_framebuffers (StThemeNodeTransition *transition,
 {
   StThemeNodeTransitionPrivate *priv = transition->priv;
   guint width, height;
+  CoglError *catch_error = NULL;
 
   /* template material to avoid unnecessary shader compilation */
   static CoglHandle material_template = COGL_INVALID_HANDLE;
@@ -263,19 +264,33 @@ setup_framebuffers (StThemeNodeTransition *transition,
                                                   COGL_TEXTURE_NO_SLICING,
                                                   COGL_PIXEL_FORMAT_ANY);
 
-  g_return_val_if_fail (priv->old_texture != COGL_INVALID_HANDLE, FALSE);
-  g_return_val_if_fail (priv->new_texture != COGL_INVALID_HANDLE, FALSE);
+  if (priv->old_texture == COGL_INVALID_HANDLE)
+    return FALSE;
+
+  if (priv->new_texture == COGL_INVALID_HANDLE)
+    return FALSE;
 
   if (priv->old_offscreen)
     cogl_handle_unref (priv->old_offscreen);
   priv->old_offscreen = cogl_offscreen_new_with_texture (priv->old_texture);
+  if (!cogl_framebuffer_allocate (COGL_FRAMEBUFFER (priv->old_offscreen), &catch_error))
+    {
+      cogl_object_unref (priv->old_offscreen);
+      cogl_error_free (catch_error);
+      priv->old_offscreen = COGL_INVALID_HANDLE;
+      return FALSE;
+    }
 
   if (priv->new_offscreen)
     cogl_handle_unref (priv->new_offscreen);
   priv->new_offscreen = cogl_offscreen_new_with_texture (priv->new_texture);
-
-  g_return_val_if_fail (priv->old_offscreen != COGL_INVALID_HANDLE, FALSE);
-  g_return_val_if_fail (priv->new_offscreen != COGL_INVALID_HANDLE, FALSE);
+  if (!cogl_framebuffer_allocate (COGL_FRAMEBUFFER (priv->new_offscreen), &catch_error))
+    {
+      cogl_object_unref (priv->new_offscreen);
+      cogl_error_free (catch_error);
+      priv->new_offscreen = COGL_INVALID_HANDLE;
+      return FALSE;
+    }
 
   if (priv->material == NULL)
     {