[gtk+/gtk-3-6] IconTheme: Move changed emission to an idle

[Matthias Clasen <matthiasc src gnome org>]

commit 3b0fd46b1ad53aa07e038241f4c8a980ed72780f
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Jun 19 16:48:43 2013 -0400

    IconTheme: Move changed emission to an idle
    
    By delaying the emission to an idle we avoid a lot of tricky
    reentrancy issues. For instance, a normal gtk_icon_theme_choose_icon()
    call could in very rare cases (when a user updated an icon theme) emit
    a signal which could affect the icon currently being looked up.  This
    kind of reentrancy is very hard to test against, especially when it is
    so rare, so we're better of avoiding it.
    
    There is no real value to get the change signal directly anyway. All
    it can do is affect which icon is rendered the next frame, and we will
    handle the queued emission before rendering. Not to mention that icon
    theme change detection is polled anyway, so it is already delayed.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=694755

 gtk/gtkicontheme.c |   36 +++++++++++++++++++++---------------
 1 files changed, 21 insertions(+), 15 deletions(-)
---
diff --git a/gtk/gtkicontheme.c b/gtk/gtkicontheme.c
index 58b643f..0490061 100644
--- a/gtk/gtkicontheme.c
+++ b/gtk/gtkicontheme.c
@@ -194,7 +194,7 @@ struct _GtkIconThemePrivate
   glong last_stat_time;
   GList *dir_mtimes;
 
-  gulong reset_styles_idle;
+  gulong theme_changed_idle;
 };
 
 struct _GtkIconInfo
@@ -690,7 +690,7 @@ free_dir_mtime (IconThemeDirMtime *dir_mtime)
 }
 
 static gboolean
-reset_styles_idle (gpointer user_data)
+theme_changed_idle (gpointer user_data)
 {
   GtkIconTheme *icon_theme;
   GtkIconThemePrivate *priv;
@@ -698,14 +698,27 @@ reset_styles_idle (gpointer user_data)
   icon_theme = GTK_ICON_THEME (user_data);
   priv = icon_theme->priv;
 
+  g_signal_emit (icon_theme, signal_changed, 0);
+
   if (priv->screen && priv->is_screen_singleton)
     gtk_style_context_reset_widgets (priv->screen);
 
-  priv->reset_styles_idle = 0;
+  priv->theme_changed_idle = 0;
 
   return FALSE;
 }
 
+ static void
+queue_theme_changed (GtkIconTheme *icon_theme)
+{
+  GtkIconThemePrivate *priv = icon_theme->priv;
+
+  if (!priv->theme_changed_idle)
+    priv->theme_changed_idle =
+      gdk_threads_add_idle_full (GTK_PRIORITY_RESIZE - 2,
+                                 theme_changed_idle, icon_theme, NULL);
+}
+
 static void
 do_theme_change (GtkIconTheme *icon_theme)
 {
@@ -717,12 +730,7 @@ do_theme_change (GtkIconTheme *icon_theme)
   GTK_NOTE (ICONTHEME, 
            g_print ("change to icon theme \"%s\"\n", priv->current_theme));
   blow_themes (icon_theme);
-  g_signal_emit (icon_theme, signal_changed, 0);
-
-  if (!priv->reset_styles_idle)
-    priv->reset_styles_idle = 
-      gdk_threads_add_idle_full (GTK_PRIORITY_RESIZE - 2, 
-                      reset_styles_idle, icon_theme, NULL);
+  queue_theme_changed (icon_theme);
 }
 
 static void
@@ -754,10 +762,10 @@ gtk_icon_theme_finalize (GObject *object)
   icon_theme = GTK_ICON_THEME (object);
   priv = icon_theme->priv;
 
-  if (priv->reset_styles_idle)
+  if (priv->theme_changed_idle)
     {
-      g_source_remove (priv->reset_styles_idle);
-      priv->reset_styles_idle = 0;
+      g_source_remove (priv->theme_changed_idle);
+      priv->theme_changed_idle = 0;
     }
 
   unset_screen (icon_theme);
@@ -1297,9 +1305,7 @@ ensure_valid_themes (GtkIconTheme *icon_theme)
       load_themes (icon_theme);
 
       if (was_valid)
-       {
-         g_signal_emit (icon_theme, signal_changed, 0);
-       }
+       queue_theme_changed (icon_theme);
     }
 
   priv->loading_themes = FALSE;