[glib] GSettings: bind to writablity of a key

[Ryan Lortie <ryanl src gnome org>]

commit f5990c1aefe364cfdd8c6d4bcdcc5dce60ced003
Author: Ryan Lortie <desrt desrt ca>
Date:   Tue Apr 20 12:30:12 2010 -0400

    GSettings: bind to writablity of a key

 gio/gio.symbols |    1 +
 gio/gsettings.c |  103 ++++++++++++++++++++++++++++++++++++++----------------
 gio/gsettings.h |    5 +++
 3 files changed, 78 insertions(+), 31 deletions(-)
---
diff --git a/gio/gio.symbols b/gio/gio.symbols
index cedfd39..6b22ee1 100644
--- a/gio/gio.symbols
+++ b/gio/gio.symbols
@@ -1390,6 +1390,7 @@ g_settings_backend_changed_tree
 #if IN_FILE(__G_SETTINGS_C__)
 g_settings_apply
 g_settings_bind
+g_settings_bind_writable
 g_settings_bind_with_mapping
 g_settings_delay
 g_settings_get
diff --git a/gio/gsettings.c b/gio/gsettings.c
index f8d0150..b7d0cba 100644
--- a/gio/gsettings.c
+++ b/gio/gsettings.c
@@ -1181,21 +1181,6 @@ g_settings_binding_key_changed (GSettings   *settings,
 }
 
 static void
-g_settings_binding_writable_changed (GSettings   *settings,
-                                     const gchar *key,
-                                     gpointer     user_data)
-{
-  GSettingsBinding *binding = user_data;
-  gboolean writable;
-
-  g_assert (settings == binding->settings);
-  g_assert (key == binding->key);
-
-  writable = g_settings_is_writable (settings, key);
-  g_object_set (binding->object, "sensitive", writable, NULL);
-}
-
-static void
 g_settings_binding_property_changed (GObject          *object,
                                      const GParamSpec *pspec,
                                      gpointer          user_data)
@@ -1303,7 +1288,6 @@ g_settings_bind_with_mapping (GSettings               *settings,
 {
   GSettingsBinding *binding;
   GObjectClass *objectclass;
-  gboolean bind_sensitive;
   gchar *detailed_signal;
   GQuark binding_quark;
 
@@ -1365,10 +1349,11 @@ g_settings_bind_with_mapping (GSettings               *settings,
       GParamSpec *sensitive;
 
       sensitive = g_object_class_find_property (objectclass, "sensitive");
-      bind_sensitive = sensitive && sensitive->value_type == G_TYPE_BOOLEAN;
+
+      if (sensitive && sensitive->value_type == G_TYPE_BOOLEAN)
+        g_settings_bind_writable (settings, binding->key,
+                                  object, "sensitive", FALSE);
     }
-  else
-    bind_sensitive = FALSE;
 
   if (flags & G_SETTINGS_BIND_SET)
     {
@@ -1400,23 +1385,79 @@ g_settings_bind_with_mapping (GSettings               *settings,
       g_settings_binding_key_changed (settings, binding->key, binding);
     }
 
-  if (bind_sensitive)
-    {
-      detailed_signal = g_strdup_printf ("writable-changed::%s", key);
-      binding->writable_handler_id =
-        g_signal_connect (settings, detailed_signal,
-                          G_CALLBACK (g_settings_binding_writable_changed),
-                          binding);
-      g_free (detailed_signal);
-
-      g_settings_binding_writable_changed (settings, binding->key, binding);
-    }
-
   binding_quark = g_settings_binding_quark (property);
   g_object_set_qdata_full (object, binding_quark,
                            binding, g_settings_binding_free);
 }
 
+typedef struct
+{
+  GSettings *settings;
+  gpointer object;
+  const gchar *key;
+  const gchar *property;
+  gboolean inverted;
+  gulong handler_id;
+} GSettingsWritableBinding;
+
+static void
+g_settings_writable_binding_free (gpointer data)
+{
+  GSettingsWritableBinding *binding = data;
+
+  g_signal_handler_disconnect (binding->settings, binding->handler_id);
+  g_object_unref (binding->settings);
+}
+
+static void
+g_settings_binding_writable_changed (GSettings   *settings,
+                                     const gchar *key,
+                                     gpointer     user_data)
+{
+  GSettingsWritableBinding *binding = user_data;
+  gboolean writable;
+
+  g_assert (settings == binding->settings);
+  g_assert (key == binding->key);
+
+  writable = g_settings_is_writable (settings, key);
+
+  if (binding->inverted)
+    writable = !writable;
+
+  g_object_set (binding->object, binding->property, writable, NULL);
+}
+
+
+void
+g_settings_bind_writable (GSettings   *settings,
+                          const gchar *key,
+                          gpointer     object,
+                          const gchar *property,
+                          gboolean     inverted)
+{
+  GSettingsWritableBinding *binding;
+  gchar *detailed_signal;
+
+  binding = g_slice_new (GSettingsWritableBinding);
+  binding->settings = g_object_ref (settings);
+  binding->object = object;
+  binding->property = g_intern_string (property);
+  binding->inverted = inverted;
+
+  detailed_signal = g_strdup_printf ("writable-changed::%s", key);
+  binding->handler_id =
+    g_signal_connect (settings, detailed_signal,
+                      G_CALLBACK (g_settings_binding_writable_changed),
+                      binding);
+  g_free (detailed_signal);
+
+  g_object_set_qdata_full (object, g_settings_binding_quark (property),
+                           binding, g_settings_writable_binding_free);
+
+  g_settings_binding_writable_changed (settings, binding->key, binding);
+}
+
 /**
  * g_settings_unbind:
  * @object: the object
diff --git a/gio/gsettings.h b/gio/gsettings.h
index 23fe2e4..79d84b5 100644
--- a/gio/gsettings.h
+++ b/gio/gsettings.h
@@ -197,6 +197,11 @@ void                    g_settings_bind_with_mapping                    (GSettin
                                                                          GSettingsBindSetMapping  set_mapping,
                                                                          gpointer                 user_data,
                                                                          GDestroyNotify           destroy);
+void                    g_settings_bind_writable                        (GSettings               *settings,
+                                                                         const gchar             *key,
+                                                                         gpointer                 object,
+                                                                         const gchar             *property,
+                                                                         gboolean                 inverted);
 void                    g_settings_unbind                               (gpointer                 object,
                                                                          const gchar             *property);