core: Drop meta_stack_windows_cmp and derived functions

Since these will not be used from now on, we can finally clean up
meta_stack_windows_cmp, window_stack_cmp and meta_display_stack_cmp.
Now the only comparison function is meta_window_stack_position_compare.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4183>

src/core/display-private.h

@@ -196,10 +196,6 @@ MetaDisplay * meta_display_new (MetaContext  *context,
 void meta_display_manage_all_xwindows (MetaDisplay *display);
 #endif
 
-/* Utility function to compare the stacking of two windows */
-int           meta_display_stack_cmp           (const void *a,
-                                                const void *b);
-
 /* Each MetaWindow is uniquely identified by a 64-bit "stamp"; unlike a
  * a MetaWindow *, a stamp will never be recycled
  */

src/core/display.c

@@ -2383,16 +2383,6 @@ meta_display_unmanage_windows (MetaDisplay *display,
   g_slist_free (winlist);
 }
 
-int
-meta_display_stack_cmp (const void *a,
-                        const void *b)
-{
-  MetaWindow *aw = (void*) a;
-  MetaWindow *bw = (void*) b;
-
-  return meta_stack_windows_cmp (aw->display->stack, aw, bw);
-}
-
 /**
  * meta_display_sort_windows_by_stacking:
  * @display: a #MetaDisplay
@@ -3552,17 +3542,6 @@ static const char* meta_window_queue_names[META_N_QUEUE_TYPES] =
   };
 #endif
 
-static int
-window_stack_cmp (gconstpointer a,
-                  gconstpointer b)
-{
-  MetaWindow *aw = (gpointer) a;
-  MetaWindow *bw = (gpointer) b;
-
-  return meta_stack_windows_cmp (aw->display->stack,
-                                 aw, bw);
-}
-
 static void
 warn_on_incorrectly_unmanaged_window (MetaWindow *window)
 {

src/core/stack.c

@@ -942,27 +942,6 @@ meta_stack_list_windows (MetaStack     *stack,
   return workspace_windows;
 }
 
-int
-meta_stack_windows_cmp (MetaStack  *stack,
-                        MetaWindow *window_a,
-                        MetaWindow *window_b)
-{
-  /* -1 means a below b */
-
-  meta_stack_ensure_sorted (stack); /* update constraints, layers */
-
-  if (window_a->layer < window_b->layer)
-    return -1;
-  else if (window_a->layer > window_b->layer)
-    return 1;
-  else if (window_a->stack_position < window_b->stack_position)
-    return -1;
-  else if (window_a->stack_position > window_b->stack_position)
-    return 1;
-  else
-    return 0; /* not reached */
-}
-
 void
 meta_window_set_stack_position_no_sync (MetaWindow *window,
                                         int         position)

src/core/stack.h

@@ -257,29 +257,6 @@ MetaWindow * meta_stack_get_below (MetaStack  *stack,
 GList * meta_stack_list_windows (MetaStack     *stack,
                                  MetaWorkspace *workspace);
 
-/**
- * meta_stack_windows_cmp:
- * @stack: A stack containing both window_a and window_b
- * @window_a: A window
- * @window_b  Another window
- *
- * Comparison function for windows within a stack.  This is not directly
- * suitable for use within a standard comparison routine, because it takes
- * an extra parameter; you will need to wrap it.
- *
- * (FIXME: We could remove the stack parameter and use the stack of
- * the screen of window A, and complain if the stack of the screen of
- * window B differed; then this would be a usable general comparison function.)
- *
- * (FIXME: Apparently identical to compare_window_position(). Merge them.)
- *
- * \return -1 if window_a is below window_b, honouring layers; 1 if it's
- *         above it; 0 if you passed in the same window twice!
- */
-int meta_stack_windows_cmp (MetaStack  *stack,
-                            MetaWindow *window_a,
-                            MetaWindow *window_b);
-
 /**
  * meta_window_set_stack_position:
  * @window: The window which is moving.