Replace EBinding with GBinding.

GObject now does property bindings itself.

Requires GLib >= 2.26.

6 files changed, 77 insertions, 678 deletions

diff --git a/e-util/Makefile.am b/e-util/Makefile.am
index 4b08698896..619f88c27a 100644
--- a/e-util/Makefile.am
+++ b/e-util/Makefile.am
@@ -15,7 +15,6 @@ eutilinclude_HEADERS = 				\
 	e-alert-activity.h			\
 	e-alert-dialog.h			\
 	e-alert-sink.h				\
-	e-binding.h				\
 	e-bit-array.h				\
 	e-categories-config.h			\
 	e-charset.h				\
@@ -95,7 +94,6 @@ libeutil_la_SOURCES =				\
 	e-alert-activity.c			\
 	e-alert-dialog.c			\
 	e-alert-sink.c				\
-	e-binding.c				\
 	e-bit-array.c				\
 	e-categories-config.c			\
 	e-charset.c				\
diff --git a/e-util/e-binding.c b/e-util/e-binding.c
deleted file mode 100644
index 4b0f563a43..0000000000
--- a/e-util/e-binding.c
+++ /dev/null
@@ -1,557 +0,0 @@
-/*
- * e-binding.c
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) version 3.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with the program; if not, see <http://www.gnu.org/licenses/>
- *
- *
- * Copyright (C) 1999-2008 Novell, Inc. (www.novell.com)
- *
- */
-
-#ifdef HAVE_CONFIG_H
-#include <config.h>
-#endif
-
-#include "e-binding.h"
-
-static gpointer
-e_binding_warn (GObject *object,
-                const gchar *property_name)
-{
-	g_warning (
-		"%s instances have no '%s' property to bind to",
-		G_OBJECT_TYPE_NAME (object), property_name);
-
-	return NULL;
-}
-
-static gboolean
-e_binding_transform_negate (const GValue *src_value,
-                            GValue *dst_value)
-{
-	if (!g_value_transform (src_value, dst_value))
-		return FALSE;
-
-	g_value_set_boolean (dst_value, !g_value_get_boolean (dst_value));
-
-	return TRUE;
-}
-
-static void
-e_bind_properties_transfer (GObject *src_object,
-                            GParamSpec *src_pspec,
-                            GObject *dst_object,
-                            GParamSpec *dst_pspec,
-                            EBindingTransform  transform,
-                            gpointer user_data)
-{
-	const gchar *src_name;
-	const gchar *dst_name;
-	gboolean result;
-	GValue src_value = { 0, };
-	GValue dst_value = { 0, };
-
-	src_name = g_param_spec_get_name (src_pspec);
-	dst_name = g_param_spec_get_name (dst_pspec);
-
-	g_value_init (&src_value, G_PARAM_SPEC_VALUE_TYPE (src_pspec));
-	g_object_get_property (src_object, src_name, &src_value);
-
-	g_value_init (&dst_value, G_PARAM_SPEC_VALUE_TYPE (dst_pspec));
-	result = (*transform) (&src_value, &dst_value, user_data);
-
-	g_value_unset (&src_value);
-
-	g_return_if_fail (result);
-
-	g_param_value_validate (dst_pspec, &dst_value);
-	g_object_set_property (dst_object, dst_name, &dst_value);
-	g_value_unset (&dst_value);
-}
-
-static void
-e_bind_properties_notify (GObject *src_object,
-                          GParamSpec *src_pspec,
-                          gpointer data)
-{
-	EBindingLink *link = data;
-
-	/* Block the destination handler for mutual bindings,
-	 * so we don't recurse here. */
-	if (link->dst_handler != 0)
-		g_signal_handler_block (link->dst_object, link->dst_handler);
-
-	e_bind_properties_transfer (
-		src_object, src_pspec,
-		link->dst_object, link->dst_pspec,
-		link->transform, link->user_data);
-
-	/* Unblock destination handler. */
-	if (link->dst_handler != 0)
-		g_signal_handler_unblock (link->dst_object, link->dst_handler);
-}
-
-static void
-e_binding_on_dst_object_destroy (gpointer  data,
-                                 GObject  *object)
-{
-	EBinding *binding = data;
-
-	binding->link.dst_object = NULL;
-
-	/* Calls e_binding_on_disconnect() */
-	g_signal_handler_disconnect (
-		binding->src_object, binding->link.handler);
-}
-
-static void
-e_binding_on_disconnect (gpointer data,
-                         GClosure *closure)
-{
-	EBindingLink *link = data;
-	EBinding *binding;
-
-	binding = (EBinding *)
-		(((gchar *) link) - G_STRUCT_OFFSET (EBinding, link));
-
-	if (binding->base.destroy != NULL)
-		binding->base.destroy (link->user_data);
-
-	if (link->dst_object != NULL)
-		g_object_weak_unref (
-			link->dst_object,
-			e_binding_on_dst_object_destroy, binding);
-
-	g_slice_free (EBinding, binding);
-}
-
-/* Recursively calls e_mutual_binding_on_disconnect_object2() */
-static void
-e_mutual_binding_on_disconnect_object1 (gpointer data,
-                                        GClosure *closure)
-{
-	EMutualBinding *binding;
-	EBindingLink *link = data;
-	GObject *object2;
-
-	binding = (EMutualBinding *)
-		(((gchar *) link) - G_STRUCT_OFFSET (EMutualBinding, direct));
-	binding->reverse.dst_object = NULL;
-
-	object2 = binding->direct.dst_object;
-	if (object2 != NULL) {
-		if (binding->base.destroy != NULL)
-			binding->base.destroy (binding->direct.user_data);
-		binding->direct.dst_object = NULL;
-		g_signal_handler_disconnect (object2, binding->reverse.handler);
-		g_slice_free (EMutualBinding, binding);
-	}
-}
-
-/* Recursively calls e_mutual_binding_on_disconnect_object1() */
-static void
-e_mutual_binding_on_disconnect_object2 (gpointer data,
-                                        GClosure *closure)
-{
-	EMutualBinding *binding;
-	EBindingLink *link = data;
-	GObject *object1;
-
-	binding = (EMutualBinding *)
-		(((gchar *) link) - G_STRUCT_OFFSET (EMutualBinding, reverse));
-	binding->direct.dst_object = NULL;
-
-	object1 = binding->reverse.dst_object;
-	if (object1 != NULL) {
-		binding->reverse.dst_object = NULL;
-		g_signal_handler_disconnect (object1, binding->direct.handler);
-	}
-}
-
-static void
-e_binding_link_init (EBindingLink *link,
-                     GObject *src_object,
-                     const gchar *src_property,
-                     GObject *dst_object,
-                     GParamSpec *dst_pspec,
-                     EBindingTransform transform,
-                     GClosureNotify destroy_notify,
-                     gpointer user_data)
-{
-	gchar *signal_name;
-
-	link->dst_object = dst_object;
-	link->dst_pspec = dst_pspec;
-	link->dst_handler = 0;
-	link->transform = transform;
-	link->user_data = user_data;
-
-	signal_name = g_strconcat ("notify::", src_property, NULL);
-	link->handler = g_signal_connect_data (
-		src_object, signal_name,
-		G_CALLBACK (e_bind_properties_notify),
-		link, destroy_notify, 0);
-	g_free (signal_name);
-}
-
-/**
- * e_binding_new:
- * @src_object: The source #GObject.
- * @src_property: The name of the property to bind from.
- * @dst_object: The destination #GObject.
- * @dst_property: The name of the property to bind to.
- *
- * One-way binds @src_property in @src_object to @dst_property
- * in @dst_object.
- *
- * Before binding the value of @dst_property is set to the
- * value of @src_property.
- *
- * Returns: The descriptor of the binding. It is automatically
- *          removed if one of the objects is finalized.
- **/
-EBinding *
-e_binding_new (gpointer src_object,
-               const gchar *src_property,
-               gpointer dst_object,
-               const gchar *dst_property)
-{
-	return e_binding_new_full (
-		src_object, src_property,
-		dst_object, dst_property,
-		NULL, NULL, NULL);
-}
-
-/**
- * e_binding_new_full:
- * @src_object: The source #GObject.
- * @src_property: The name of the property to bind from.
- * @dst_object: The destination #GObject.
- * @dst_property: The name of the property to bind to.
- * @transform: Transformation function or %NULL.
- * @destroy_notify: Callback function that is called on
- *                  disconnection with @user_data or %NULL.
- * @user_data: User data associated with the binding.
- *
- * One-way binds @src_property in @src_object to @dst_property
- * in @dst_object.
- *
- * Before binding the value of @dst_property is set to the
- * value of @src_property.
- *
- * Returns: The descriptor of the binding. It is automatically
- *          removed if one of the objects is finalized.
- **/
-EBinding *
-e_binding_new_full (gpointer src_object,
-                    const gchar *src_property,
-                    gpointer dst_object,
-                    const gchar *dst_property,
-                    EBindingTransform transform,
-                    GDestroyNotify destroy_notify,
-                    gpointer user_data)
-{
-	EBinding *binding;
-	GParamSpec *src_pspec;
-	GParamSpec *dst_pspec;
-
-	g_return_val_if_fail (G_IS_OBJECT (src_object), NULL);
-	g_return_val_if_fail (G_IS_OBJECT (dst_object), NULL);
-
-	src_pspec = g_object_class_find_property (
-		G_OBJECT_GET_CLASS (src_object), src_property);
-	dst_pspec = g_object_class_find_property (
-		G_OBJECT_GET_CLASS (dst_object), dst_property);
-
-	if (src_pspec == NULL)
-		return e_binding_warn (src_object, src_property);
-	if (dst_pspec == NULL)
-		return e_binding_warn (dst_object, dst_property);
-
-	if (transform == NULL)
-		transform = (EBindingTransform) g_value_transform;
-
-	e_bind_properties_transfer (
-		src_object, src_pspec,
-		dst_object, dst_pspec,
-		transform, user_data);
-
-	binding = g_slice_new (EBinding);
-	binding->src_object = src_object;
-	binding->base.destroy = destroy_notify;
-
-	e_binding_link_init (
-		&binding->link, src_object, src_property, dst_object,
-		dst_pspec, transform, e_binding_on_disconnect, user_data);
-
-	g_object_weak_ref (
-		dst_object, e_binding_on_dst_object_destroy, binding);
-
-	return binding;
-}
-
-/**
- * e_binding_new_with_negation:
- * @src_object: The source #GObject.
- * @src_property: The name of the property to bind from.
- * @dst_object: The destination #GObject.
- * @dst_property: The name of the property to bind to.
- *
- * Convenience function for binding with boolean negation of value.
- *
- * Returns: The descriptor of the binding. It is automatically
- *          removed if one of the objects is finalized.
- **/
-EBinding *
-e_binding_new_with_negation (gpointer src_object,
-                             const gchar *src_property,
-                             gpointer dst_object,
-                             const gchar *dst_property)
-{
-	EBindingTransform transform;
-
-	transform = (EBindingTransform) e_binding_transform_negate;
-
-	return e_binding_new_full (
-		src_object, src_property,
-		dst_object, dst_property,
-		transform, NULL, NULL);
-}
-
-/**
- * e_binding_unbind:
- * @binding: An #EBinding to unbind.
- *
- * Disconnects the binding between two properties. Should be
- * rarely used by applications.
- *
- * This functions also calls the @destroy_notify function that
- * was specified when @binding was created.
- **/
-void
-e_binding_unbind (EBinding *binding)
-{
-	g_signal_handler_disconnect (
-		binding->src_object, binding->link.handler);
-}
-
-/**
- * e_mutual_binding_new:
- * @object1 : The first #GObject.
- * @property1: The first property to bind.
- * @object2 : The second #GObject.
- * @property2: The second property to bind.
- *
- * Mutually binds values of two properties.
- *
- * Before binding the value of @property2 is set to the value
- * of @property1.
- *
- * Returns: The descriptor of the binding. It is automatically
- *          removed if one of the objects is finalized.
- **/
-EMutualBinding *
-e_mutual_binding_new (gpointer object1,
-                      const gchar *property1,
-                      gpointer object2,
-                      const gchar *property2)
-{
-	return e_mutual_binding_new_full (
-		object1, property1,
-		object2, property2,
-		NULL, NULL, NULL, NULL);
-}
-
-/**
- * e_mutual_binding_new_full:
- * @object1: The first #GObject.
- * @property1: The first property to bind.
- * @object2: The second #GObject.
- * @property2: The second property to bind.
- * @transform: Transformation function or %NULL.
- * @reverse_transform: The inverse transformation function or %NULL.
- * @destroy_notify: Callback function called on disconnection with
- *                  @user_data as argument or %NULL.
- * @user_data: User data associated with the binding.
- *
- * Mutually binds values of two properties.
- *
- * Before binding the value of @property2 is set to the value of
- * @property1.
- *
- * Both @transform and @reverse_transform should simultaneously be
- * %NULL or non-%NULL. If they are non-%NULL, they should be reverse
- * in each other.
- *
- * Returns: The descriptor of the binding. It is automatically
- *          removed if one of the objects is finalized.
- **/
-EMutualBinding *
-e_mutual_binding_new_full (gpointer object1,
-                           const gchar *property1,
-                           gpointer object2,
-                           const gchar *property2,
-                           EBindingTransform transform,
-                           EBindingTransform reverse_transform,
-                           GDestroyNotify destroy_notify,
-                           gpointer user_data)
-{
-	EMutualBinding *binding;
-	GParamSpec *pspec1;
-	GParamSpec *pspec2;
-
-	g_return_val_if_fail (G_IS_OBJECT (object1), NULL);
-	g_return_val_if_fail (G_IS_OBJECT (object2), NULL);
-
-	pspec1 = g_object_class_find_property (
-		G_OBJECT_GET_CLASS (object1), property1);
-	pspec2 = g_object_class_find_property (
-		G_OBJECT_GET_CLASS (object2), property2);
-
-	if (pspec1 == NULL)
-		return e_binding_warn (object1, property1);
-	if (pspec2 == NULL)
-		return e_binding_warn (object2, property2);
-
-	if (transform == NULL)
-		transform = (EBindingTransform) g_value_transform;
-
-	if (reverse_transform == NULL)
-		reverse_transform = (EBindingTransform) g_value_transform;
-
-	e_bind_properties_transfer (
-		object1, pspec1, object2,
-		pspec2, transform, user_data);
-
-	binding = g_slice_new (EMutualBinding);
-	binding->base.destroy = destroy_notify;
-
-	e_binding_link_init (
-		&binding->direct,
-		object1, property1, object2, pspec2, transform,
-		e_mutual_binding_on_disconnect_object1, user_data);
-
-	e_binding_link_init (
-		&binding->reverse,
-		object2, property2, object1, pspec1, reverse_transform,
-		e_mutual_binding_on_disconnect_object2, user_data);
-
-	/* Tell each link about the reverse link for mutual bindings,
-	 * to make sure that we do not ever recurse in notify (yeah,
-	 * the GObject notify dispatching is really weird!). */
-	binding->direct.dst_handler = binding->reverse.handler;
-	binding->reverse.dst_handler = binding->direct.handler;
-
-	return binding;
-}
-
-/**
- * e_mutual_binding_new_with_negation:
- * @object1: The first #GObject.
- * @property1: The first property to bind.
- * @object2: The second #GObject.
- * @property2: The second property to bind.
- *
- * Convenience function for binding with boolean negation of value.
- *
- * Returns: The descriptor of the binding. It is automatically removed
- *          if one of the objects if finalized.
- **/
-EMutualBinding*
-e_mutual_binding_new_with_negation (gpointer object1,
-                                    const gchar *property1,
-                                    gpointer object2,
-                                    const gchar *property2)
-{
-	EBindingTransform transform;
-
-	transform = (EBindingTransform) e_binding_transform_negate;
-
-	return e_mutual_binding_new_full (
-		object1, property1,
-		object2, property2,
-		transform, transform,
-		NULL, NULL);
-}
-
-/**
- * e_mutual_binding_unbind:
- * @binding: An #EMutualBinding to unbind.
- *
- * Disconnects the binding between two properties. Should be
- * rarely used by applications.
- *
- * This functions also calls the @destroy_notify function that
- * was specified when @binding was created.
- **/
-void
-e_mutual_binding_unbind (EMutualBinding *binding)
-{
-	g_signal_handler_disconnect (
-		binding->reverse.dst_object, binding->direct.handler);
-}
-
-/**
- * e_binding_transform_color_to_string:
- * @src_value: a #GValue of type #GDK_TYPE_COLOR
- * @dst_value: a #GValue of type #G_TYPE_STRING
- * @user_data: not used
- *
- * Transforms a #GdkColor value to a color string specification.
- *
- * Returns: %TRUE always
- **/
-gboolean
-e_binding_transform_color_to_string (const GValue *src_value,
-                                     GValue *dst_value,
-                                     gpointer user_data)
-{
-	const GdkColor *color;
-	gchar *string;
-
-	color = g_value_get_boxed (src_value);
-	string = gdk_color_to_string (color);
-	g_value_set_string (dst_value, string);
-	g_free (string);
-
-	return TRUE;
-}
-
-/**
- * e_binding_transform_string_to_color:
- * @src_value: a #GValue of type #G_TYPE_STRING
- * @dst_value: a #GValue of type #GDK_TYPE_COLOR
- * @user_data: not used
- *
- * Transforms a color string specification to a #GdkColor.
- *
- * Returns: %TRUE if color string specification was valid
- **/
-gboolean
-e_binding_transform_string_to_color (const GValue *src_value,
-                                     GValue *dst_value,
-                                     gpointer user_data)
-{
-	GdkColor color;
-	const gchar *string;
-	gboolean success = FALSE;
-
-	string = g_value_get_string (src_value);
-	if (gdk_color_parse (string, &color)) {
-		g_value_set_boxed (dst_value, &color);
-		success = TRUE;
-	}
-
-	return success;
-}
diff --git a/e-util/e-binding.h b/e-util/e-binding.h
deleted file mode 100644
index 180edc9f49..0000000000
--- a/e-util/e-binding.h
+++ /dev/null
@@ -1,117 +0,0 @@
-/*
- * e-binding.h
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) version 3.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with the program; if not, see <http://www.gnu.org/licenses/>
- *
- *
- * Copyright (C) 1999-2008 Novell, Inc. (www.novell.com)
- *
- */
-
-/* This is a direct rip-off of Xfce's excellent ExoBinding API,
- * which binds two GObject properties together.  ExoBinding was
- * written by Benedikt Meurer <benny@xfce.org>. */
-
-#ifndef E_BINDING_H
-#define E_BINDING_H
-
-#include <gdk/gdk.h>
-
-G_BEGIN_DECLS
-
-typedef struct _EBinding EBinding;
-typedef struct _EBindingBase EBindingBase;
-typedef struct _EBindingLink EBindingLink;
-typedef struct _EMutualBinding EMutualBinding;
-
-typedef gboolean	(*EBindingTransform)	(const GValue *src_value,
-						 GValue *dst_value,
-						 gpointer user_data);
-
-struct _EBindingBase {
-	GDestroyNotify destroy;
-};
-
-struct _EBindingLink {
-	GObject *dst_object;
-	GParamSpec *dst_pspec;
-	gulong dst_handler; /* only set for mutual bindings */
-	gulong handler;
-	EBindingTransform transform;
-	gpointer user_data;
-};
-
-struct _EBinding {
-	/*< private >*/
-	GObject *src_object;
-	EBindingBase base;
-	EBindingLink link;
-};
-
-struct _EMutualBinding {
-	/*< private >*/
-	EBindingBase  base;
-	EBindingLink  direct;
-	EBindingLink  reverse;
-};
-
-EBinding *	e_binding_new			(gpointer src_object,
-						 const gchar *src_property,
-						 gpointer dst_object,
-						 const gchar *dst_property);
-EBinding *	e_binding_new_full		(gpointer src_object,
-						 const gchar *src_property,
-						 gpointer dst_object,
-						 const gchar *dst_property,
-						 EBindingTransform transform,
-						 GDestroyNotify destroy_notify,
-						 gpointer user_data);
-EBinding *	e_binding_new_with_negation	(gpointer src_object,
-						 const gchar *src_property,
-						 gpointer dst_object,
-						 const gchar *dst_property);
-void		e_binding_unbind		(EBinding *binding);
-
-EMutualBinding *e_mutual_binding_new		(gpointer object1,
-						 const gchar *property1,
-						 gpointer object2,
-						 const gchar *property2);
-EMutualBinding *e_mutual_binding_new_full	(gpointer object1,
-						 const gchar *property1,
-						 gpointer object2,
-						 const gchar *property2,
-						 EBindingTransform transform,
-						 EBindingTransform reverse_transform,
-						 GDestroyNotify destroy_notify,
-						 gpointer user_data);
-EMutualBinding *e_mutual_binding_new_with_negation
-						(gpointer object1,
-						 const gchar *property1,
-						 gpointer object2,
-						 const gchar *property2);
-void		e_mutual_binding_unbind		(EMutualBinding *binding);
-
-/* Useful transformation functions */
-gboolean	e_binding_transform_color_to_string
-						(const GValue *src_value,
-						 GValue *dst_value,
-						 gpointer user_data);
-gboolean	e_binding_transform_string_to_color
-						(const GValue *src_value,
-						 GValue *dst_value,
-						 gpointer user_data);
-
-G_END_DECLS
-
-#endif /* E_BINDING_H */
diff --git a/e-util/e-config.c b/e-util/e-config.c
index dd51f8efc7..6646fa17d9 100644
--- a/e-util/e-config.c
+++ b/e-util/e-config.c
@@ -31,7 +31,6 @@
 #include <glib/gi18n.h>
 
 #include "e-config.h"
-#include "e-binding.h"
 
 #include <glib/gi18n.h>
 
@@ -1704,7 +1703,10 @@ ech_config_section_factory (EConfig *config,
 	/* This is why we have a custom factory for sections.
 	 * When the plugin is disabled the frame is invisible. */
 	plugin = group->hook->hook.plugin;
-	e_binding_new (plugin, "enabled", widget, "visible");
+	g_object_bind_property (
+		plugin, "enabled",
+		widget, "visible",
+		G_BINDING_SYNC_CREATE);
 
 	parent = widget;
 
diff --git a/e-util/e-util.c b/e-util/e-util.c
index 68662bd3d4..22f792c3a7 100644
--- a/e-util/e-util.c
+++ b/e-util/e-util.c
@@ -1494,3 +1494,64 @@ e_util_set_source_combo_box_list (GtkWidget *source_combo_box,
 	g_object_unref (gconf_client);
 }
 
+/**
+ * e_binding_transform_color_to_string:
+ * @binding: a #GBinding
+ * @source_value: a #GValue of type #GDK_TYPE_COLOR
+ * @target_value: a #GValue of type #G_TYPE_STRING
+ * @user_data: not used
+ *
+ * Transforms a #GdkColor value to a color string specification.
+ *
+ * Returns: %TRUE always
+ **/
+gboolean
+e_binding_transform_color_to_string (GBinding *binding,
+                                     const GValue *source_value,
+                                     GValue *target_value,
+                                     gpointer user_data)
+{
+	const GdkColor *color;
+	gchar *string;
+
+	g_return_val_if_fail (G_IS_BINDING (binding), FALSE);
+
+	color = g_value_get_boxed (source_value);
+	string = gdk_color_to_string (color);
+	g_value_set_string (target_value, string);
+	g_free (string);
+
+	return TRUE;
+}
+
+/**
+ * e_binding_transform_string_to_color:
+ * @binding: a #GBinding
+ * @source_value: a #GValue of type #G_TYPE_STRING
+ * @target_value: a #GValue of type #GDK_TYPE_COLOR
+ * @user_data: not used
+ *
+ * Transforms a color string specification to a #GdkColor.
+ *
+ * Returns: %TRUE if color string specification was valid
+ **/
+gboolean
+e_binding_transform_string_to_color (GBinding *binding,
+                                     const GValue *source_value,
+                                     GValue *target_value,
+                                     gpointer user_data)
+{
+	GdkColor color;
+	const gchar *string;
+	gboolean success = FALSE;
+
+	g_return_val_if_fail (G_IS_BINDING (binding), FALSE);
+
+	string = g_value_get_string (source_value);
+	if (gdk_color_parse (string, &color)) {
+		g_value_set_boxed (target_value, &color);
+		success = TRUE;
+	}
+
+	return success;
+}
diff --git a/e-util/e-util.h b/e-util/e-util.h
index 71fc12f431..9aa24f3d87 100644
--- a/e-util/e-util.h
+++ b/e-util/e-util.h
@@ -142,6 +142,18 @@ void		e_util_set_source_combo_box_list
 						(GtkWidget *source_combo_box,
 						 const gchar *source_gconf_path);
 
+/* Useful GBinding transformation functions */
+gboolean	e_binding_transform_color_to_string
+						(GBinding *binding,
+						 const GValue *source_value,
+						 GValue *target_value,
+						 gpointer user_data);
+gboolean	e_binding_transform_string_to_color
+						(GBinding *binding,
+						 const GValue *source_value,
+						 GValue *target_value,
+						 gpointer user_data);
+
 G_END_DECLS
 
 #endif /* E_UTIL_H */