[gtk+] IconTheme: Move changed emission to an idle

[Alexander Larsson <alexl src gnome org>]

commit 159cccfe7b50e1e0fbede08132abfc74f4206fdb
Author: Alexander Larsson <alexl redhat com>
Date:   Wed Jun 19 11:06:20 2013 +0200

    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 |   38 +++++++++++++++++++++++---------------
 1 files changed, 23 insertions(+), 15 deletions(-)
---
diff --git a/gtk/gtkicontheme.c b/gtk/gtkicontheme.c
index 4af2537..9a8e4b3 100644
--- a/gtk/gtkicontheme.c
+++ b/gtk/gtkicontheme.c
@@ -203,7 +203,7 @@ struct _GtkIconThemePrivate
   glong last_stat_time;
   GList *dir_mtimes;
 
-  gulong reset_styles_idle;
+  gulong theme_changed_idle;
 };
 
 typedef struct {
@@ -795,7 +795,7 @@ 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;
@@ -803,15 +803,28 @@ 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)
 {
   GtkIconThemePrivate *priv = icon_theme->priv;
@@ -820,16 +833,13 @@ do_theme_change (GtkIconTheme *icon_theme)
 
   if (!priv->themes_valid)
     return;
-  
+
   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
@@ -864,10 +874,10 @@ gtk_icon_theme_finalize (GObject *object)
   g_hash_table_destroy (priv->info_cache);
   g_assert (priv->info_cache_lru == NULL);
 
-  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);
@@ -1410,9 +1420,7 @@ 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;