Stacking update: Use a GLib idle source

Ever since the switch from libev to GLib, we have a hack in place. We
use g_main_context_set_poll_func() to replace g_poll() (which is just a
wrapper around poll()) with our own function that does lots of house
keeping. This commit is part of getting rid of this hack: It moves one
step that is done in this poll-replacement into a GLib idle source.

Namely, this commit makes us use an idle source instead of a boolean to
track whether we have to update the stacking order.

Signed-off-by: Uli Schlachter <psychon@znc.in>

event.h

@@ -41,7 +41,6 @@ awesome_refresh(void)
 {
     luaA_emit_refresh();
     client_refresh();
-    stack_refresh();
     client_destroy_later();
     return xcb_flush(globalconf.connection);
 }

globalconf.h

@@ -190,6 +190,8 @@ typedef struct
     xcb_colormap_t default_cmap;
     /** Do we have to reban clients? */
     guint banning_update_id;
+    /** Do we have to update the stacking order? */
+    guint stacking_update_id;
     /** Tag list */
     tag_array_t tags;
     /** List of registered xproperties */

stack.c

@@ -61,14 +61,6 @@ stack_client_append(client_t *c)
     stack_windows();
 }
 
-static bool need_stack_refresh = false;
-
-void
-stack_windows(void)
-{
-    need_stack_refresh = true;
-}
-
 /** Stack a window above another window, without causing errors.
  * \param w The window.
  * \param previous The window which should be below this window.
@@ -159,11 +151,11 @@ client_layer_translator(client_t *c)
  * \todo It might be worth stopping to restack everyone and only stack `c'
  * relatively to the first matching in the list.
  */
-void
-stack_refresh()
+static gboolean
+stack_refresh(gpointer unused)
 {
-    if(!need_stack_refresh)
-        return;
+    assert(globalconf.stacking_update_id != 0);
+    globalconf.stacking_update_id = 0;
 
     xcb_window_t next = XCB_NONE;
 
@@ -195,7 +187,14 @@ stack_refresh()
             next = (*drawin)->window;
         }
 
-    need_stack_refresh = false;
+    return G_SOURCE_REMOVE;
+}
+
+void
+stack_windows(void)
+{
+    if (globalconf.stacking_update_id == 0)
+        globalconf.stacking_update_id = g_idle_add(stack_refresh, NULL);
 }
 
 

stack.h

@@ -28,7 +28,6 @@ void stack_client_remove(client_t *);
 void stack_client_push(client_t *);
 void stack_client_append(client_t *);
 void stack_windows(void);
-void stack_refresh(void);
 
 #endif
 // vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80