ui/frames: check that compositing is not only requested, but also available.

Enabling code that is supposed to be used in compositing conditions is
harmful if compositing is not actually available. Just checking the
preference is not enough to make sure that compositing is available -
the X server might be missing crucial extensions for compositing to
work, which in turn correctly disables the internal compositor.

The end result is graphical issues like black borders around windows in
such situations.

Make sure that compositing is both requested AND available to fix this
bug.

5 files changed, 33 insertions, 22 deletions

diff --git a/src/core/frame.c b/src/core/frame.c
index 957f6c76..e1eec2a4 100644
--- a/src/core/frame.c
+++ b/src/core/frame.c
@@ -152,6 +152,7 @@ meta_window_ensure_frame (MetaWindow *window)
 
   /* Shape mask */
   meta_ui_apply_frame_shape (frame->window->screen->ui,
+                             frame->window->display,
                              frame->xwindow,
                              frame->rect.width,
                              frame->rect.height,
@@ -325,6 +326,7 @@ update_shape (MetaFrame *frame)
   if (frame->need_reapply_frame_shape)
     {
       meta_ui_apply_frame_shape (frame->window->screen->ui,
+                                 frame->window->display,
                                  frame->xwindow,
                                  frame->rect.width,
                                  frame->rect.height,
diff --git a/src/include/ui.h b/src/include/ui.h
index c02e78a2..9d95e37a 100644
--- a/src/include/ui.h
+++ b/src/include/ui.h
@@ -26,6 +26,7 @@
 
 /* Don't include gtk.h or gdk.h here */
 #include "common.h"
+#include "types.h"
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
 #include <glib.h>
@@ -91,11 +92,12 @@ void meta_ui_map_frame   (MetaUI *ui,
 void meta_ui_unmap_frame (MetaUI *ui,
                           Window  xwindow);
 
-void meta_ui_apply_frame_shape  (MetaUI  *ui,
-                                 Window   xwindow,
-                                 int      new_window_width,
-                                 int      new_window_height,
-                                 gboolean window_has_shape);
+void meta_ui_apply_frame_shape  (MetaUI      *ui,
+                                 MetaDisplay *display,
+                                 Window       xwindow,
+                                 int          new_window_width,
+                                 int          new_window_height,
+                                 gboolean     window_has_shape);
 
 cairo_region_t *meta_ui_get_frame_bounds (MetaUI *ui,
                                           Window  xwindow,
diff --git a/src/ui/frames.c b/src/ui/frames.c
index d65dac82..ad7e10c8 100644
--- a/src/ui/frames.c
+++ b/src/ui/frames.c
@@ -37,6 +37,7 @@
 #include "theme.h"
 #include "prefs.h"
 #include "ui.h"
+#include "display.h"
 
 #ifdef HAVE_SHAPE
 #include <X11/extensions/shape.h>
@@ -1063,11 +1064,12 @@ get_frame_region (int window_width,
 #endif /* HAVE_SHAPE */
 
 void
-meta_frames_apply_shapes (MetaFrames *frames,
-                          Window      xwindow,
-                          int         new_window_width,
-                          int         new_window_height,
-                          gboolean    window_has_shape)
+meta_frames_apply_shapes (MetaFrames  *frames,
+                          MetaDisplay *meta_display,
+                          Window       xwindow,
+                          int          new_window_width,
+                          int          new_window_height,
+                          gboolean     window_has_shape)
 {
 #ifdef HAVE_SHAPE
   /* Apply shapes as if window had new_window_width, new_window_height */
@@ -1095,7 +1097,9 @@ meta_frames_apply_shapes (MetaFrames *frames,
 
   meta_frames_calc_geometry (frames, frame, &fgeom);
 
-  compositing_manager = meta_prefs_get_compositing_manager ();
+  compositing_manager = meta_prefs_get_compositing_manager () &&
+                        meta_display &&
+                        !!(meta_display_get_compositor (meta_display));
 
   if (!window_has_shape && compositing_manager)
     return;
diff --git a/src/ui/frames.h b/src/ui/frames.h
index ad86ee44..f4821e43 100644
--- a/src/ui/frames.h
+++ b/src/ui/frames.h
@@ -28,6 +28,7 @@
 #include <gdk/gdkx.h>
 #include "common.h"
 #include "theme.h"
+#include "types.h"
 
 typedef enum
 {
@@ -135,11 +136,12 @@ void meta_frames_get_borders (MetaFrames       *frames,
                               Window            xwindow,
                               MetaFrameBorders *borders);
 
-void meta_frames_apply_shapes (MetaFrames *frames,
-                               Window      xwindow,
-                               int         new_window_width,
-                               int         new_window_height,
-                               gboolean    window_has_shape);
+void meta_frames_apply_shapes (MetaFrames  *frames,
+                               MetaDisplay *meta_display,
+                               Window       xwindow,
+                               int          new_window_width,
+                               int          new_window_height,
+                               gboolean     window_has_shape);
 cairo_region_t *meta_frames_get_frame_bounds (MetaFrames *frames,
                                               Window      xwindow,
                                               int         window_width,
diff --git a/src/ui/ui.c b/src/ui/ui.c
index 9976c701..2b15cc82 100644
--- a/src/ui/ui.c
+++ b/src/ui/ui.c
@@ -458,13 +458,14 @@ meta_ui_repaint_frame (MetaUI *ui,
 }
 
 void
-meta_ui_apply_frame_shape  (MetaUI  *ui,
-                            Window   xwindow,
-                            int      new_window_width,
-                            int      new_window_height,
-                            gboolean window_has_shape)
+meta_ui_apply_frame_shape  (MetaUI      *ui,
+                            MetaDisplay *display,
+                            Window       xwindow,
+                            int          new_window_width,
+                            int          new_window_height,
+                            gboolean     window_has_shape)
 {
-  meta_frames_apply_shapes (ui->frames, xwindow,
+  meta_frames_apply_shapes (ui->frames, display, xwindow,
                             new_window_width, new_window_height,
                             window_has_shape);
 }