Ignore false GSettings key change notifications

Similar to GObject::notify, the GSettings::changed can be emitted
even if a key didn't change. It's up to the user (aka evolution)
to test for real changes, thus let's do it. It may have certain
performance positive impact too.

7 files changed, 139 insertions, 12 deletions

diff --git a/calendar/gui/e-day-view-time-item.c b/calendar/gui/e-day-view-time-item.c
index f85b09eebd..b30951bb5b 100644
--- a/calendar/gui/e-day-view-time-item.c
+++ b/calendar/gui/e-day-view-time-item.c
@@ -727,16 +727,21 @@ edvti_second_zone_changed_cb (GSettings *settings,
 {
 	EDayViewTimeItem *time_item = user_data;
 	EDayView *day_view;
+	icaltimezone *second_zone;
 	gchar *location;
 
 	g_return_if_fail (user_data != NULL);
 	g_return_if_fail (E_IS_DAY_VIEW_TIME_ITEM (time_item));
 
 	location = calendar_config_get_day_second_zone ();
-	time_item->priv->second_zone =
-		location ? icaltimezone_get_builtin_timezone (location) : NULL;
+	second_zone = location ? icaltimezone_get_builtin_timezone (location) : NULL;
 	g_free (location);
 
+	if (second_zone == time_item->priv->second_zone)
+		return;
+
+	time_item->priv->second_zone = second_zone;
+
 	day_view = e_day_view_time_item_get_day_view (time_item);
 	gtk_widget_set_size_request (
 		day_view->time_canvas,
diff --git a/e-util/e-web-view.c b/e-util/e-web-view.c
index 398540128d..afb3cc9fef 100644
--- a/e-util/e-web-view.c
+++ b/e-util/e-web-view.c
@@ -69,6 +69,8 @@ struct _EWebViewPrivate {
 
 	GSettings *aliasing_settings;
 	gulong antialiasing_changed_handler_id;
+
+	GHashTable *old_settings;
 };
 
 struct _AsyncContext {
@@ -897,6 +899,11 @@ web_view_finalize (GObject *object)
 	while (!g_queue_is_empty (&priv->highlights))
 		g_free (g_queue_pop_head (&priv->highlights));
 
+	if (priv->old_settings) {
+		g_hash_table_destroy (priv->old_settings);
+		priv->old_settings = NULL;
+	}
+
 	/* Chain up to parent's finalize() method. */
 	G_OBJECT_CLASS (e_web_view_parent_class)->finalize (object);
 }
@@ -1407,6 +1414,28 @@ web_view_selectable_select_all (ESelectable *selectable)
 	e_web_view_select_all (E_WEB_VIEW (selectable));
 }
 
+static void
+e_web_view_test_change_and_update_fonts_cb (EWebView *web_view,
+					    const gchar *key,
+					    GSettings *settings)
+{
+	GVariant *new_value, *old_value;
+
+	new_value = g_settings_get_value (settings, key);
+	old_value = g_hash_table_lookup (web_view->priv->old_settings, key);
+
+	if (!new_value || !old_value || !g_variant_equal (new_value, old_value)) {
+		if (new_value)
+			g_hash_table_insert (web_view->priv->old_settings, g_strdup (key), new_value);
+		else
+			g_hash_table_remove (web_view->priv->old_settings, key);
+
+		e_web_view_update_fonts (web_view);
+	} else if (new_value) {
+		g_variant_unref (new_value);
+	}
+}
+
 static gpointer
 web_view_disable_webkit_3rd_party_plugins (gpointer unused)
 {
@@ -1670,6 +1699,8 @@ e_web_view_init (EWebView *web_view)
 
 	web_view->priv = E_WEB_VIEW_GET_PRIVATE (web_view);
 
+	web_view->priv->old_settings = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, (GDestroyNotify) g_variant_unref);
+
 	/* XXX No WebKitWebView class method pointers to
 	 *     override so we have to use signal handlers. */
 
@@ -1727,11 +1758,11 @@ e_web_view_init (EWebView *web_view)
 	web_view->priv->font_settings = g_object_ref (settings);
 	handler_id = g_signal_connect_swapped (
 		settings, "changed::font-name",
-		G_CALLBACK (e_web_view_update_fonts), web_view);
+		G_CALLBACK (e_web_view_test_change_and_update_fonts_cb), web_view);
 	web_view->priv->font_name_changed_handler_id = handler_id;
 	handler_id = g_signal_connect_swapped (
 		settings, "changed::monospace-font-name",
-		G_CALLBACK (e_web_view_update_fonts), web_view);
+		G_CALLBACK (e_web_view_test_change_and_update_fonts_cb), web_view);
 	web_view->priv->monospace_font_name_changed_handler_id = handler_id;
 	g_object_unref (settings);
 
@@ -1744,7 +1775,7 @@ e_web_view_init (EWebView *web_view)
 		web_view->priv->aliasing_settings = g_object_ref (settings);
 		handler_id = g_signal_connect_swapped (
 			settings, "changed::antialiasing",
-			G_CALLBACK (e_web_view_update_fonts), web_view);
+			G_CALLBACK (e_web_view_test_change_and_update_fonts_cb), web_view);
 		web_view->priv->antialiasing_changed_handler_id = handler_id;
 		g_object_unref (settings);
 		g_settings_schema_unref (settings_schema);
diff --git a/libemail-engine/mail-config.c b/libemail-engine/mail-config.c
index 17532f2b3b..e9f3e8e998 100644
--- a/libemail-engine/mail-config.c
+++ b/libemail-engine/mail-config.c
@@ -73,11 +73,24 @@ settings_jh_headers_changed (GSettings *settings,
 	gchar **strv;
 	gint i;
 
+	strv = g_settings_get_strv (settings, "junk-custom-header");
+	if (key) {
+		for (i = 0, node = config->jh_header; strv[i] && node; i++, node = g_slist_next (node)) {
+			if (g_strcmp0 (node->data, strv[i]) != 0)
+				break;
+		}
+
+		/* both lists are read to the end, thus they are the same */
+		if (!node && !strv[i]) {
+			g_strfreev (strv);
+			return;
+		}
+	}
+
 	g_slist_foreach (config->jh_header, (GFunc) g_free, NULL);
 	g_slist_free (config->jh_header);
 	config->jh_header = NULL;
 
-	strv = g_settings_get_strv (settings, "junk-custom-header");
 	for (i = 0; strv[i] != NULL; i++)
 		config->jh_header = g_slist_append (config->jh_header, g_strdup (strv[i]));
 	g_strfreev (strv);
@@ -108,6 +121,9 @@ settings_jh_check_changed (GSettings *settings,
                            const gchar *key,
                            EMailSession *session)
 {
+	if (key && config->jh_check == g_settings_get_boolean (settings, "junk-check-custom-header"))
+		return;
+
 	config->jh_check = g_settings_get_boolean (settings, "junk-check-custom-header");
 	if (!config->jh_check) {
 		camel_session_set_junk_headers (
diff --git a/mail/e-mail-display.c b/mail/e-mail-display.c
index 5dc02860c7..61751dfbee 100644
--- a/mail/e-mail-display.c
+++ b/mail/e-mail-display.c
@@ -59,6 +59,8 @@ struct _EMailDisplayPrivate {
 	GHashTable *widgets;
 
 	guint scheduled_reload;
+
+	GHashTable *old_settings;
 };
 
 enum {
@@ -1135,6 +1137,22 @@ mail_display_dispose (GObject *object)
 }
 
 static void
+mail_display_finalize (GObject *object)
+{
+	EMailDisplayPrivate *priv;
+
+	priv = E_MAIL_DISPLAY_GET_PRIVATE (object);
+
+	if (priv->old_settings) {
+		g_hash_table_destroy (priv->old_settings);
+		priv->old_settings = NULL;
+	}
+
+	/* Chain up to parent's finalize() method. */
+	G_OBJECT_CLASS (e_mail_display_parent_class)->finalize (object);
+}
+
+static void
 mail_display_constructed (GObject *object)
 {
 	e_extensible_load_extensions (E_EXTENSIBLE (object));
@@ -1406,6 +1424,28 @@ mail_display_set_fonts (EWebView *web_view,
 }
 
 static void
+e_mail_display_test_change_and_update_fonts_cb (EMailDisplay *mail_display,
+						const gchar *key,
+						GSettings *settings)
+{
+	GVariant *new_value, *old_value;
+
+	new_value = g_settings_get_value (settings, key);
+	old_value = g_hash_table_lookup (mail_display->priv->old_settings, key);
+
+	if (!new_value || !old_value || !g_variant_equal (new_value, old_value)) {
+		if (new_value)
+			g_hash_table_insert (mail_display->priv->old_settings, g_strdup (key), new_value);
+		else
+			g_hash_table_remove (mail_display->priv->old_settings, key);
+
+		e_web_view_update_fonts (E_WEB_VIEW (mail_display));
+	} else if (new_value) {
+		g_variant_unref (new_value);
+	}
+}
+
+static void
 e_mail_display_class_init (EMailDisplayClass *class)
 {
 	GObjectClass *object_class;
@@ -1419,6 +1459,7 @@ e_mail_display_class_init (EMailDisplayClass *class)
 	object_class->set_property = mail_display_set_property;
 	object_class->get_property = mail_display_get_property;
 	object_class->dispose = mail_display_dispose;
+	object_class->finalize = mail_display_finalize;
 
 	widget_class = GTK_WIDGET_CLASS (class);
 	widget_class->realize = mail_display_realize;
@@ -1496,6 +1537,8 @@ e_mail_display_init (EMailDisplay *display)
 
 	display->priv = E_MAIL_DISPLAY_GET_PRIVATE (display);
 
+	display->priv->old_settings = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, (GDestroyNotify) g_variant_unref);
+
 	/* Set invalid mode so that MODE property initialization is run
 	 * completely (see e_mail_display_set_mode) */
 	display->priv->mode = E_MAIL_FORMATTER_MODE_INVALID;
@@ -1536,13 +1579,13 @@ e_mail_display_init (EMailDisplay *display)
 	display->priv->settings = g_settings_new ("org.gnome.evolution.mail");
 	g_signal_connect_swapped (
 		display->priv->settings , "changed::monospace-font",
-		G_CALLBACK (e_web_view_update_fonts), display);
+		G_CALLBACK (e_mail_display_test_change_and_update_fonts_cb), display);
 	g_signal_connect_swapped (
 		display->priv->settings , "changed::variable-width-font",
-		G_CALLBACK (e_web_view_update_fonts), display);
+		G_CALLBACK (e_mail_display_test_change_and_update_fonts_cb), display);
 	g_signal_connect_swapped (
 		display->priv->settings , "changed::use-custom-font",
-		G_CALLBACK (e_web_view_update_fonts), display);
+		G_CALLBACK (e_mail_display_test_change_and_update_fonts_cb), display);
 
 	e_web_view_update_fonts (E_WEB_VIEW (display));
 
diff --git a/modules/calendar/e-cal-shell-backend.c b/modules/calendar/e-cal-shell-backend.c
index 0a9c80fb3d..65f88022d8 100644
--- a/modules/calendar/e-cal-shell-backend.c
+++ b/modules/calendar/e-cal-shell-backend.c
@@ -666,7 +666,17 @@ static void
 cal_shell_backend_use_system_timezone_changed_cb (GSettings *settings,
                                                   const gchar *key)
 {
-	g_signal_emit_by_name (settings, "changed::timezone", timezone);
+	/* the '-1' is a trick to emit the change the first time */
+	static gint old_value = -1;
+	gboolean value;
+
+	value = g_settings_get_boolean (settings, key);
+
+	if ((value ? 1 : 0) != old_value) {
+		old_value = value ? 1 : 0;
+
+		g_signal_emit_by_name (settings, "changed::timezone", timezone);
+	}
 }
 
 static void
diff --git a/modules/calendar/e-task-shell-view-private.c b/modules/calendar/e-task-shell-view-private.c
index 863fd0136e..5a26284575 100644
--- a/modules/calendar/e-task-shell-view-private.c
+++ b/modules/calendar/e-task-shell-view-private.c
@@ -88,7 +88,21 @@ task_shell_view_hide_completed_tasks_changed_cb (GSettings *settings,
                                                  const gchar *key,
                                                  ETaskShellView *task_shell_view)
 {
-	task_shell_view_process_completed_tasks (task_shell_view);
+	GVariant *new_value, *old_value;
+
+	new_value = g_settings_get_value (settings, key);
+	old_value = g_hash_table_lookup (task_shell_view->priv->old_settings, key);
+
+	if (!new_value || !old_value || !g_variant_equal (new_value, old_value)) {
+		if (new_value)
+			g_hash_table_insert (task_shell_view->priv->old_settings, g_strdup (key), new_value);
+		else
+			g_hash_table_remove (task_shell_view->priv->old_settings, key);
+
+		task_shell_view_process_completed_tasks (task_shell_view);
+	} else if (new_value) {
+		g_variant_unref (new_value);
+	}
 }
 
 static void
@@ -210,6 +224,8 @@ task_shell_view_notify_view_id_cb (EShellView *shell_view)
 void
 e_task_shell_view_private_init (ETaskShellView *task_shell_view)
 {
+	task_shell_view->priv->old_settings = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, (GDestroyNotify) g_variant_unref);
+
 	e_signal_connect_notify (
 		task_shell_view, "notify::view-id",
 		G_CALLBACK (task_shell_view_notify_view_id_cb), NULL);
@@ -553,7 +569,11 @@ e_task_shell_view_private_dispose (ETaskShellView *task_shell_view)
 void
 e_task_shell_view_private_finalize (ETaskShellView *task_shell_view)
 {
-	/* XXX Nothing to do? */
+	if (task_shell_view->priv->old_settings) {
+		g_hash_table_destroy (task_shell_view->priv->old_settings);
+		task_shell_view->priv->old_settings = NULL;
+	}
+
 }
 
 void
diff --git a/modules/calendar/e-task-shell-view-private.h b/modules/calendar/e-task-shell-view-private.h
index b2a1511c9a..d29bd2e771 100644
--- a/modules/calendar/e-task-shell-view-private.h
+++ b/modules/calendar/e-task-shell-view-private.h
@@ -120,6 +120,8 @@ struct _ETaskShellViewPrivate {
 	guint update_completed_timeout;
 
 	guint confirm_purge : 1;
+
+	GHashTable *old_settings;
 };
 
 void		e_task_shell_view_private_init