gobject/gbindinggroup.c - third_party/glib - Git at Google

 /* GObject - GLib Type, Object, Parameter and Signal Library
  *
  * Copyright (C) 2015-2022 Christian Hergert <christian@hergert.me>
  * Copyright (C) 2015 Garrett Regier <garrettregier@gmail.com>
  *
  * This library 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 2.1 of the License, or (at your option) any later version.
  *
  * This library 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 this library; if not, see <http://www.gnu.org/licenses/>.
  *
  * SPDX-License-Identifier: LGPL-2.1-or-later
  */

 #include "config.h"
 #include "glib.h"
 #include "glibintl.h"

 #include "gbindinggroup.h"
 #include "gparamspecs.h"

 /**
  * SECTION:gbindinggroup
  * @Title: GBindingGroup
  * @Short_description: Binding multiple properties as a group
  * @include: glib-object.h
  *
  * The #GBindingGroup can be used to bind multiple properties
  * from an object collectively.
  *
  * Use the various methods to bind properties from a single source
  * object to multiple destination objects. Properties can be bound
  * bidirectionally and are connected when the source object is set
  * with g_binding_group_set_source().
  *
  * Since: 2.72
  */

 #if 0
 # define DEBUG_BINDINGS
 #endif

 struct _GBindingGroup
 {
   GObject    parent_instance;
   GMutex     mutex;
   GObject   *source;         /* (owned weak) */
   GPtrArray *lazy_bindings;  /* (owned) (element-type LazyBinding) */
 };

 typedef struct _GBindingGroupClass
 {
   GObjectClass parent_class;
 } GBindingGroupClass;

 typedef struct
 {
   GBindingGroup      *group;  /* (unowned) */
   const char         *source_property;  /* (interned) */
   const char         *target_property;  /* (interned) */
   GObject            *target;  /* (owned weak) */
   GBinding           *binding;  /* (unowned) */
   gpointer            user_data;
   GDestroyNotify      user_data_destroy;
   gpointer            transform_to;  /* (nullable) (owned) */
   gpointer            transform_from;  /* (nullable) (owned) */
   GBindingFlags       binding_flags;
   guint               using_closures : 1;
 } LazyBinding;

 G_DEFINE_TYPE (GBindingGroup, g_binding_group, G_TYPE_OBJECT)

 typedef enum
 {
   PROP_SOURCE = 1,
   N_PROPS
 } GBindingGroupProperty;

 static void lazy_binding_free (gpointer data);

 static GParamSpec *properties[N_PROPS];

 static void
 g_binding_group_connect (GBindingGroup *self,
                          LazyBinding   *lazy_binding)
 {
   GBinding *binding;

   g_assert (G_IS_BINDING_GROUP (self));
   g_assert (self->source != NULL);
   g_assert (lazy_binding != NULL);
   g_assert (lazy_binding->binding == NULL);
   g_assert (lazy_binding->target != NULL);
   g_assert (lazy_binding->target_property != NULL);
   g_assert (lazy_binding->source_property != NULL);

 #ifdef DEBUG_BINDINGS
   {
     GFlagsClass *flags_class;
     g_autofree gchar *flags_str = NULL;

     flags_class = g_type_class_ref (G_TYPE_BINDING_FLAGS);
     flags_str = g_flags_to_string (flags_class, lazy_binding->binding_flags);

     g_print ("Binding %s(%p):%s to %s(%p):%s (flags=%s)\n",
              G_OBJECT_TYPE_NAME (self->source),
              self->source,
              lazy_binding->source_property,
              G_OBJECT_TYPE_NAME (lazy_binding->target),
              lazy_binding->target,
              lazy_binding->target_property,
              flags_str);

     g_type_class_unref (flags_class);
   }
 #endif

   if (!lazy_binding->using_closures)
     binding = g_object_bind_property_full (self->source,
                                            lazy_binding->source_property,
                                            lazy_binding->target,
                                            lazy_binding->target_property,
                                            lazy_binding->binding_flags,
                                            lazy_binding->transform_to,
                                            lazy_binding->transform_from,
                                            lazy_binding->user_data,
                                            NULL);
   else
     binding = g_object_bind_property_with_closures (self->source,
                                                     lazy_binding->source_property,
                                                     lazy_binding->target,
                                                     lazy_binding->target_property,
                                                     lazy_binding->binding_flags,
                                                     lazy_binding->transform_to,
                                                     lazy_binding->transform_from);

   lazy_binding->binding = binding;
 }

 static void
 g_binding_group_disconnect (LazyBinding *lazy_binding)
 {
   g_assert (lazy_binding != NULL);

   if (lazy_binding->binding != NULL)
     {
       g_binding_unbind (lazy_binding->binding);
       lazy_binding->binding = NULL;
     }
 }

 static void
 g_binding_group__source_weak_notify (gpointer  data,
                                      GObject  *where_object_was)
 {
   GBindingGroup *self = data;
   guint i;

   g_assert (G_IS_BINDING_GROUP (self));

   g_mutex_lock (&self->mutex);

   self->source = NULL;

   for (i = 0; i < self->lazy_bindings->len; i++)
     {
       LazyBinding *lazy_binding = g_ptr_array_index (self->lazy_bindings, i);

       lazy_binding->binding = NULL;
     }

   g_mutex_unlock (&self->mutex);
 }

 static void
 g_binding_group__target_weak_notify (gpointer  data,
                                      GObject  *where_object_was)
 {
   GBindingGroup *self = data;
   LazyBinding *to_free = NULL;
   guint i;

   g_assert (G_IS_BINDING_GROUP (self));

   g_mutex_lock (&self->mutex);

   for (i = 0; i < self->lazy_bindings->len; i++)
     {
       LazyBinding *lazy_binding = g_ptr_array_index (self->lazy_bindings, i);

       if (lazy_binding->target == where_object_was)
         {
           lazy_binding->target = NULL;
           lazy_binding->binding = NULL;

           to_free = g_ptr_array_steal_index_fast (self->lazy_bindings, i);
           break;
         }
     }

   g_mutex_unlock (&self->mutex);

   if (to_free != NULL)
     lazy_binding_free (to_free);
 }

 static void
 lazy_binding_free (gpointer data)
 {
   LazyBinding *lazy_binding = data;

   if (lazy_binding->target != NULL)
     {
       g_object_weak_unref (lazy_binding->target,
                            g_binding_group__target_weak_notify,
                            lazy_binding->group);
       lazy_binding->target = NULL;
     }

   g_binding_group_disconnect (lazy_binding);

   lazy_binding->group = NULL;
   lazy_binding->source_property = NULL;
   lazy_binding->target_property = NULL;

   if (lazy_binding->user_data_destroy)
     lazy_binding->user_data_destroy (lazy_binding->user_data);

   if (lazy_binding->using_closures)
     {
       g_clear_pointer (&lazy_binding->transform_to, g_closure_unref);
       g_clear_pointer (&lazy_binding->transform_from, g_closure_unref);
     }

   g_slice_free (LazyBinding, lazy_binding);
 }

 static void
 g_binding_group_dispose (GObject *object)
 {
   GBindingGroup *self = (GBindingGroup *)object;
   LazyBinding **lazy_bindings = NULL;
   gsize len = 0;
   gsize i;

   g_assert (G_IS_BINDING_GROUP (self));

   g_mutex_lock (&self->mutex);

   if (self->source != NULL)
     {
       g_object_weak_unref (self->source,
                            g_binding_group__source_weak_notify,
                            self);
       self->source = NULL;
     }

   if (self->lazy_bindings->len > 0)
     lazy_bindings = (LazyBinding **)g_ptr_array_steal (self->lazy_bindings, &len);

   g_mutex_unlock (&self->mutex);

   /* Free bindings without holding self->mutex to avoid re-entrancy
    * from collateral damage through release of binding closure data,
    * GDataList, etc.
    */
   for (i = 0; i < len; i++)
     lazy_binding_free (lazy_bindings[i]);
   g_free (lazy_bindings);

   G_OBJECT_CLASS (g_binding_group_parent_class)->dispose (object);
 }

 static void
 g_binding_group_finalize (GObject *object)
 {
   GBindingGroup *self = (GBindingGroup *)object;

   g_assert (self->lazy_bindings != NULL);
   g_assert (self->lazy_bindings->len == 0);

   g_clear_pointer (&self->lazy_bindings, g_ptr_array_unref);
   g_mutex_clear (&self->mutex);

   G_OBJECT_CLASS (g_binding_group_parent_class)->finalize (object);
 }

 static void
 g_binding_group_get_property (GObject    *object,
                               guint       prop_id,
                               GValue     *value,
                               GParamSpec *pspec)
 {
   GBindingGroup *self = G_BINDING_GROUP (object);

   switch ((GBindingGroupProperty) prop_id)
     {
     case PROP_SOURCE:
       g_value_take_object (value, g_binding_group_dup_source (self));
       break;

     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
     }
 }

 static void
 g_binding_group_set_property (GObject      *object,
                               guint         prop_id,
                               const GValue *value,
                               GParamSpec   *pspec)
 {
   GBindingGroup *self = G_BINDING_GROUP (object);

   switch ((GBindingGroupProperty) prop_id)
     {
     case PROP_SOURCE:
       g_binding_group_set_source (self, g_value_get_object (value));
       break;

     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
     }
 }

 static void
 g_binding_group_class_init (GBindingGroupClass *klass)
 {
   GObjectClass *object_class = G_OBJECT_CLASS (klass);

   object_class->dispose = g_binding_group_dispose;
   object_class->finalize = g_binding_group_finalize;
   object_class->get_property = g_binding_group_get_property;
   object_class->set_property = g_binding_group_set_property;

   /**
    * GBindingGroup:source: (nullable)
    *
    * The source object used for binding properties.
    *
    * Since: 2.72
    */
   properties[PROP_SOURCE] =
       g_param_spec_object ("source",
                            "Source",
                            "The source GObject used for binding properties.",
                            G_TYPE_OBJECT,
                            (G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS));

   g_object_class_install_properties (object_class, N_PROPS, properties);
 }

 static void
 g_binding_group_init (GBindingGroup *self)
 {
   g_mutex_init (&self->mutex);
   self->lazy_bindings = g_ptr_array_new_with_free_func (lazy_binding_free);
 }

 /**
  * g_binding_group_new:
  *
  * Creates a new #GBindingGroup.
  *
  * Returns: (transfer full): a new #GBindingGroup
  *
  * Since: 2.72
  */
 GBindingGroup *
 g_binding_group_new (void)
 {
   return g_object_new (G_TYPE_BINDING_GROUP, NULL);
 }

 /**
  * g_binding_group_dup_source:
  * @self: the #GBindingGroup
  *
  * Gets the source object used for binding properties.
  *
  * Returns: (transfer none) (nullable) (type GObject): a #GObject or %NULL.
  *
  * Since: 2.72
  */
 gpointer
 g_binding_group_dup_source (GBindingGroup *self)
 {
   GObject *source;

   g_return_val_if_fail (G_IS_BINDING_GROUP (self), NULL);

   g_mutex_lock (&self->mutex);
   source = self->source ? g_object_ref (self->source) : NULL;
   g_mutex_unlock (&self->mutex);

   return source;
 }

 static gboolean
 g_binding_group_check_source (GBindingGroup *self,
                               gpointer       source)
 {
   guint i;

   g_assert (G_IS_BINDING_GROUP (self));
   g_assert (!source || G_IS_OBJECT (source));

   for (i = 0; i < self->lazy_bindings->len; i++)
     {
       LazyBinding *lazy_binding = g_ptr_array_index (self->lazy_bindings, i);

       g_return_val_if_fail (g_object_class_find_property (G_OBJECT_GET_CLASS (source),
                                                           lazy_binding->source_property) != NULL,
                             FALSE);
     }

   return TRUE;
 }

 /**
  * g_binding_group_set_source:
  * @self: the #GBindingGroup
  * @source: (type GObject) (nullable) (transfer none): the source #GObject,
  *   or %NULL to clear it
  *
  * Sets @source as the source object used for creating property
  * bindings. If there is already a source object all bindings from it
  * will be removed.
  *
  * Note that all properties that have been bound must exist on @source.
  *
  * Since: 2.72
  */
 void
 g_binding_group_set_source (GBindingGroup *self,
                             gpointer       source)
 {
   gboolean notify = FALSE;

   g_return_if_fail (G_IS_BINDING_GROUP (self));
   g_return_if_fail (!source || G_IS_OBJECT (source));
   g_return_if_fail (source != (gpointer) self);

   g_mutex_lock (&self->mutex);

   if (source == (gpointer) self->source)
     goto unlock;

   if (self->source != NULL)
     {
       guint i;

       g_object_weak_unref (self->source,
                            g_binding_group__source_weak_notify,
                            self);
       self->source = NULL;

       for (i = 0; i < self->lazy_bindings->len; i++)
         {
           LazyBinding *lazy_binding = g_ptr_array_index (self->lazy_bindings, i);

           g_binding_group_disconnect (lazy_binding);
         }
     }

   if (source != NULL && g_binding_group_check_source (self, source))
     {
       guint i;

       self->source = source;
       g_object_weak_ref (self->source,
                          g_binding_group__source_weak_notify,
                          self);

       for (i = 0; i < self->lazy_bindings->len; i++)
         {
           LazyBinding *lazy_binding;

           lazy_binding = g_ptr_array_index (self->lazy_bindings, i);
           g_binding_group_connect (self, lazy_binding);
         }
     }

   notify = TRUE;

 unlock:
   g_mutex_unlock (&self->mutex);

   if (notify)
     g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_SOURCE]);
 }

 static void
 g_binding_group_bind_helper (GBindingGroup  *self,
                              const gchar    *source_property,
                              gpointer        target,
                              const gchar    *target_property,
                              GBindingFlags   flags,
                              gpointer        transform_to,
                              gpointer        transform_from,
                              gpointer        user_data,
                              GDestroyNotify  user_data_destroy,
                              gboolean        using_closures)
 {
   LazyBinding *lazy_binding;

   g_return_if_fail (G_IS_BINDING_GROUP (self));
   g_return_if_fail (source_property != NULL);
   g_return_if_fail (self->source == NULL ||
                     g_object_class_find_property (G_OBJECT_GET_CLASS (self->source),
                                                   source_property) != NULL);
   g_return_if_fail (G_IS_OBJECT (target));
   g_return_if_fail (target_property != NULL);
   g_return_if_fail (g_object_class_find_property (G_OBJECT_GET_CLASS (target),
                                                   target_property) != NULL);
   g_return_if_fail (target != (gpointer) self ||
                     strcmp (source_property, target_property) != 0);

   g_mutex_lock (&self->mutex);

   lazy_binding = g_slice_new0 (LazyBinding);
   lazy_binding->group = self;
   lazy_binding->source_property = g_intern_string (source_property);
   lazy_binding->target_property = g_intern_string (target_property);
   lazy_binding->target = target;
   lazy_binding->binding_flags = flags | G_BINDING_SYNC_CREATE;
   lazy_binding->user_data = user_data;
   lazy_binding->user_data_destroy = user_data_destroy;
   lazy_binding->transform_to = transform_to;
   lazy_binding->transform_from = transform_from;

   if (using_closures)
     {
       lazy_binding->using_closures = TRUE;

       if (transform_to != NULL)
         g_closure_sink (g_closure_ref (transform_to));

       if (transform_from != NULL)
         g_closure_sink (g_closure_ref (transform_from));
     }

   g_object_weak_ref (target,
                      g_binding_group__target_weak_notify,
                      self);

   g_ptr_array_add (self->lazy_bindings, lazy_binding);

   if (self->source != NULL)
     g_binding_group_connect (self, lazy_binding);

   g_mutex_unlock (&self->mutex);
 }

 /**
  * g_binding_group_bind:
  * @self: the #GBindingGroup
  * @source_property: the property on the source to bind
  * @target: (type GObject) (transfer none) (not nullable): the target #GObject
  * @target_property: the property on @target to bind
  * @flags: the flags used to create the #GBinding
  *
  * Creates a binding between @source_property on the source object
  * and @target_property on @target. Whenever the @source_property
  * is changed the @target_property is updated using the same value.
  * The binding flag %G_BINDING_SYNC_CREATE is automatically specified.
  *
  * See g_object_bind_property() for more information.
  *
  * Since: 2.72
  */
 void
 g_binding_group_bind (GBindingGroup *self,
                       const gchar   *source_property,
                       gpointer       target,
                       const gchar   *target_property,
                       GBindingFlags  flags)
 {
   g_binding_group_bind_full (self, source_property,
                              target, target_property,
                              flags,
                              NULL, NULL,
                              NULL, NULL);
 }

 /**
  * g_binding_group_bind_full:
  * @self: the #GBindingGroup
  * @source_property: the property on the source to bind
  * @target: (type GObject) (transfer none) (not nullable): the target #GObject
  * @target_property: the property on @target to bind
  * @flags: the flags used to create the #GBinding
  * @transform_to: (scope notified) (nullable): the transformation function
  *     from the source object to the @target, or %NULL to use the default
  * @transform_from: (scope notified) (nullable): the transformation function
  *     from the @target to the source object, or %NULL to use the default
  * @user_data: custom data to be passed to the transformation
  *             functions, or %NULL
  * @user_data_destroy: function to be called when disposing the binding,
  *     to free the resources used by the transformation functions
  *
  * Creates a binding between @source_property on the source object and
  * @target_property on @target, allowing you to set the transformation
  * functions to be used by the binding. The binding flag
  * %G_BINDING_SYNC_CREATE is automatically specified.
  *
  * See g_object_bind_property_full() for more information.
  *
  * Since: 2.72
  */
 void
 g_binding_group_bind_full (GBindingGroup         *self,
                            const gchar           *source_property,
                            gpointer               target,
                            const gchar           *target_property,
                            GBindingFlags          flags,
                            GBindingTransformFunc  transform_to,
                            GBindingTransformFunc  transform_from,
                            gpointer               user_data,
                            GDestroyNotify         user_data_destroy)
 {
   g_binding_group_bind_helper (self, source_property,
                                target, target_property,
                                flags,
                                transform_to, transform_from,
                                user_data, user_data_destroy,
                                FALSE);
 }

 /**
  * g_binding_group_bind_with_closures: (rename-to g_binding_group_bind_full)
  * @self: the #GBindingGroup
  * @source_property: the property on the source to bind
  * @target: (type GObject) (transfer none) (not nullable): the target #GObject
  * @target_property: the property on @target to bind
  * @flags: the flags used to create the #GBinding
  * @transform_to: (nullable) (transfer none): a #GClosure wrapping the
  *     transformation function from the source object to the @target,
  *     or %NULL to use the default
  * @transform_from: (nullable) (transfer none): a #GClosure wrapping the
  *     transformation function from the @target to the source object,
  *     or %NULL to use the default
  *
  * Creates a binding between @source_property on the source object and
  * @target_property on @target, allowing you to set the transformation
  * functions to be used by the binding. The binding flag
  * %G_BINDING_SYNC_CREATE is automatically specified.
  *
  * This function is the language bindings friendly version of
  * g_binding_group_bind_property_full(), using #GClosures
  * instead of function pointers.
  *
  * See g_object_bind_property_with_closures() for more information.
  *
  * Since: 2.72
  */
 void
 g_binding_group_bind_with_closures (GBindingGroup *self,
                                     const gchar   *source_property,
                                     gpointer       target,
                                     const gchar   *target_property,
                                     GBindingFlags  flags,
                                     GClosure      *transform_to,
                                     GClosure      *transform_from)
 {
   g_binding_group_bind_helper (self, source_property,
                                target, target_property,
                                flags,
                                transform_to, transform_from,
                                NULL, NULL,
                                TRUE);
 }
	/* GObject - GLib Type, Object, Parameter and Signal Library
	*
	* Copyright (C) 2015-2022 Christian Hergert <christian@hergert.me>
	* Copyright (C) 2015 Garrett Regier <garrettregier@gmail.com>
	*
	* This library 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 2.1 of the License, or (at your option) any later version.
	*
	* This library 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 this library; if not, see <http://www.gnu.org/licenses/>.
	*
	* SPDX-License-Identifier: LGPL-2.1-or-later
	*/

	#include "config.h"
	#include "glib.h"
	#include "glibintl.h"

	#include "gbindinggroup.h"
	#include "gparamspecs.h"

	/**
	* SECTION:gbindinggroup
	* @Title: GBindingGroup
	* @Short_description: Binding multiple properties as a group
	* @include: glib-object.h
	*
	* The #GBindingGroup can be used to bind multiple properties
	* from an object collectively.
	*
	* Use the various methods to bind properties from a single source
	* object to multiple destination objects. Properties can be bound
	* bidirectionally and are connected when the source object is set
	* with g_binding_group_set_source().
	*
	* Since: 2.72
	*/

	#if 0
	# define DEBUG_BINDINGS
	#endif

	struct _GBindingGroup
	{
	GObject parent_instance;
	GMutex mutex;
	GObject source; / (owned weak) */
	GPtrArray lazy_bindings; / (owned) (element-type LazyBinding) */
	};

	typedef struct _GBindingGroupClass
	{
	GObjectClass parent_class;
	} GBindingGroupClass;

	typedef struct
	{
	GBindingGroup group; / (unowned) */
	const char source_property; / (interned) */
	const char target_property; / (interned) */
	GObject target; / (owned weak) */
	GBinding binding; / (unowned) */
	gpointer user_data;
	GDestroyNotify user_data_destroy;
	gpointer transform_to; /* (nullable) (owned) */
	gpointer transform_from; /* (nullable) (owned) */
	GBindingFlags binding_flags;
	guint using_closures : 1;
	} LazyBinding;

	G_DEFINE_TYPE (GBindingGroup, g_binding_group, G_TYPE_OBJECT)

	typedef enum
	{
	PROP_SOURCE = 1,
	N_PROPS
	} GBindingGroupProperty;

	static void lazy_binding_free (gpointer data);

	static GParamSpec *properties[N_PROPS];

	static void
	g_binding_group_connect (GBindingGroup *self,
	LazyBinding *lazy_binding)
	{
	GBinding *binding;

	g_assert (G_IS_BINDING_GROUP (self));
	g_assert (self->source != NULL);
	g_assert (lazy_binding != NULL);
	g_assert (lazy_binding->binding == NULL);
	g_assert (lazy_binding->target != NULL);
	g_assert (lazy_binding->target_property != NULL);
	g_assert (lazy_binding->source_property != NULL);

	#ifdef DEBUG_BINDINGS
	{
	GFlagsClass *flags_class;
	g_autofree gchar *flags_str = NULL;

	flags_class = g_type_class_ref (G_TYPE_BINDING_FLAGS);
	flags_str = g_flags_to_string (flags_class, lazy_binding->binding_flags);

	g_print ("Binding %s(%p):%s to %s(%p):%s (flags=%s)\n",
	G_OBJECT_TYPE_NAME (self->source),
	self->source,
	lazy_binding->source_property,
	G_OBJECT_TYPE_NAME (lazy_binding->target),
	lazy_binding->target,
	lazy_binding->target_property,
	flags_str);

	g_type_class_unref (flags_class);
	}
	#endif

	if (!lazy_binding->using_closures)
	binding = g_object_bind_property_full (self->source,
	lazy_binding->source_property,
	lazy_binding->target,
	lazy_binding->target_property,
	lazy_binding->binding_flags,
	lazy_binding->transform_to,
	lazy_binding->transform_from,
	lazy_binding->user_data,
	NULL);
	else
	binding = g_object_bind_property_with_closures (self->source,
	lazy_binding->source_property,
	lazy_binding->target,
	lazy_binding->target_property,
	lazy_binding->binding_flags,
	lazy_binding->transform_to,
	lazy_binding->transform_from);

	lazy_binding->binding = binding;
	}

	static void
	g_binding_group_disconnect (LazyBinding *lazy_binding)
	{
	g_assert (lazy_binding != NULL);

	if (lazy_binding->binding != NULL)
	{
	g_binding_unbind (lazy_binding->binding);
	lazy_binding->binding = NULL;
	}
	}

	static void
	g_binding_group__source_weak_notify (gpointer data,
	GObject *where_object_was)
	{
	GBindingGroup *self = data;
	guint i;

	g_assert (G_IS_BINDING_GROUP (self));

	g_mutex_lock (&self->mutex);

	self->source = NULL;

	for (i = 0; i < self->lazy_bindings->len; i++)
	{
	LazyBinding *lazy_binding = g_ptr_array_index (self->lazy_bindings, i);

	lazy_binding->binding = NULL;
	}

	g_mutex_unlock (&self->mutex);
	}

	static void
	g_binding_group__target_weak_notify (gpointer data,
	GObject *where_object_was)
	{
	GBindingGroup *self = data;
	LazyBinding *to_free = NULL;
	guint i;

	g_assert (G_IS_BINDING_GROUP (self));

	g_mutex_lock (&self->mutex);

	for (i = 0; i < self->lazy_bindings->len; i++)
	{
	LazyBinding *lazy_binding = g_ptr_array_index (self->lazy_bindings, i);

	if (lazy_binding->target == where_object_was)
	{
	lazy_binding->target = NULL;
	lazy_binding->binding = NULL;

	to_free = g_ptr_array_steal_index_fast (self->lazy_bindings, i);
	break;
	}
	}

	g_mutex_unlock (&self->mutex);

	if (to_free != NULL)
	lazy_binding_free (to_free);
	}

	static void
	lazy_binding_free (gpointer data)
	{
	LazyBinding *lazy_binding = data;

	if (lazy_binding->target != NULL)
	{
	g_object_weak_unref (lazy_binding->target,
	g_binding_group__target_weak_notify,
	lazy_binding->group);
	lazy_binding->target = NULL;
	}

	g_binding_group_disconnect (lazy_binding);

	lazy_binding->group = NULL;
	lazy_binding->source_property = NULL;
	lazy_binding->target_property = NULL;

	if (lazy_binding->user_data_destroy)
	lazy_binding->user_data_destroy (lazy_binding->user_data);

	if (lazy_binding->using_closures)
	{
	g_clear_pointer (&lazy_binding->transform_to, g_closure_unref);
	g_clear_pointer (&lazy_binding->transform_from, g_closure_unref);
	}

	g_slice_free (LazyBinding, lazy_binding);
	}

	static void
	g_binding_group_dispose (GObject *object)
	{
	GBindingGroup self = (GBindingGroup )object;
	LazyBinding **lazy_bindings = NULL;
	gsize len = 0;
	gsize i;

	g_assert (G_IS_BINDING_GROUP (self));

	g_mutex_lock (&self->mutex);

	if (self->source != NULL)
	{
	g_object_weak_unref (self->source,
	g_binding_group__source_weak_notify,
	self);
	self->source = NULL;
	}

	if (self->lazy_bindings->len > 0)
	lazy_bindings = (LazyBinding **)g_ptr_array_steal (self->lazy_bindings, &len);

	g_mutex_unlock (&self->mutex);

	/* Free bindings without holding self->mutex to avoid re-entrancy
	* from collateral damage through release of binding closure data,
	* GDataList, etc.
	*/
	for (i = 0; i < len; i++)
	lazy_binding_free (lazy_bindings[i]);
	g_free (lazy_bindings);

	G_OBJECT_CLASS (g_binding_group_parent_class)->dispose (object);
	}

	static void
	g_binding_group_finalize (GObject *object)
	{
	GBindingGroup self = (GBindingGroup )object;

	g_assert (self->lazy_bindings != NULL);
	g_assert (self->lazy_bindings->len == 0);

	g_clear_pointer (&self->lazy_bindings, g_ptr_array_unref);
	g_mutex_clear (&self->mutex);

	G_OBJECT_CLASS (g_binding_group_parent_class)->finalize (object);
	}

	static void
	g_binding_group_get_property (GObject *object,
	guint prop_id,
	GValue *value,
	GParamSpec *pspec)
	{
	GBindingGroup *self = G_BINDING_GROUP (object);

	switch ((GBindingGroupProperty) prop_id)
	{
	case PROP_SOURCE:
	g_value_take_object (value, g_binding_group_dup_source (self));
	break;

	default:
	G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
	}
	}

	static void
	g_binding_group_set_property (GObject *object,
	guint prop_id,
	const GValue *value,
	GParamSpec *pspec)
	{
	GBindingGroup *self = G_BINDING_GROUP (object);

	switch ((GBindingGroupProperty) prop_id)
	{
	case PROP_SOURCE:
	g_binding_group_set_source (self, g_value_get_object (value));
	break;

	default:
	G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
	}
	}

	static void
	g_binding_group_class_init (GBindingGroupClass *klass)
	{
	GObjectClass *object_class = G_OBJECT_CLASS (klass);

	object_class->dispose = g_binding_group_dispose;
	object_class->finalize = g_binding_group_finalize;
	object_class->get_property = g_binding_group_get_property;
	object_class->set_property = g_binding_group_set_property;

	/**
	* GBindingGroup:source: (nullable)
	*
	* The source object used for binding properties.
	*
	* Since: 2.72
	*/
	properties[PROP_SOURCE] =
	g_param_spec_object ("source",
	"Source",
	"The source GObject used for binding properties.",
	G_TYPE_OBJECT,
	(G_PARAM_READWRITE \| G_PARAM_EXPLICIT_NOTIFY \| G_PARAM_STATIC_STRINGS));

	g_object_class_install_properties (object_class, N_PROPS, properties);
	}

	static void
	g_binding_group_init (GBindingGroup *self)
	{
	g_mutex_init (&self->mutex);
	self->lazy_bindings = g_ptr_array_new_with_free_func (lazy_binding_free);
	}

	/**
	* g_binding_group_new:
	*
	* Creates a new #GBindingGroup.
	*
	* Returns: (transfer full): a new #GBindingGroup
	*
	* Since: 2.72
	*/
	GBindingGroup *
	g_binding_group_new (void)
	{
	return g_object_new (G_TYPE_BINDING_GROUP, NULL);
	}

	/**
	* g_binding_group_dup_source:
	* @self: the #GBindingGroup
	*
	* Gets the source object used for binding properties.
	*
	* Returns: (transfer none) (nullable) (type GObject): a #GObject or %NULL.
	*
	* Since: 2.72
	*/
	gpointer
	g_binding_group_dup_source (GBindingGroup *self)
	{
	GObject *source;

	g_return_val_if_fail (G_IS_BINDING_GROUP (self), NULL);

	g_mutex_lock (&self->mutex);
	source = self->source ? g_object_ref (self->source) : NULL;
	g_mutex_unlock (&self->mutex);

	return source;
	}

	static gboolean
	g_binding_group_check_source (GBindingGroup *self,
	gpointer source)
	{
	guint i;

	g_assert (G_IS_BINDING_GROUP (self));
	g_assert (!source \|\| G_IS_OBJECT (source));

	for (i = 0; i < self->lazy_bindings->len; i++)
	{
	LazyBinding *lazy_binding = g_ptr_array_index (self->lazy_bindings, i);

	g_return_val_if_fail (g_object_class_find_property (G_OBJECT_GET_CLASS (source),
	lazy_binding->source_property) != NULL,
	FALSE);
	}

	return TRUE;
	}

	/**
	* g_binding_group_set_source:
	* @self: the #GBindingGroup
	* @source: (type GObject) (nullable) (transfer none): the source #GObject,
	* or %NULL to clear it
	*
	* Sets @source as the source object used for creating property
	* bindings. If there is already a source object all bindings from it
	* will be removed.
	*
	* Note that all properties that have been bound must exist on @source.
	*
	* Since: 2.72
	*/
	void
	g_binding_group_set_source (GBindingGroup *self,
	gpointer source)
	{
	gboolean notify = FALSE;

	g_return_if_fail (G_IS_BINDING_GROUP (self));
	g_return_if_fail (!source \|\| G_IS_OBJECT (source));
	g_return_if_fail (source != (gpointer) self);

	g_mutex_lock (&self->mutex);

	if (source == (gpointer) self->source)
	goto unlock;

	if (self->source != NULL)
	{
	guint i;

	g_object_weak_unref (self->source,
	g_binding_group__source_weak_notify,
	self);
	self->source = NULL;

	for (i = 0; i < self->lazy_bindings->len; i++)
	{
	LazyBinding *lazy_binding = g_ptr_array_index (self->lazy_bindings, i);

	g_binding_group_disconnect (lazy_binding);
	}
	}

	if (source != NULL && g_binding_group_check_source (self, source))
	{
	guint i;

	self->source = source;
	g_object_weak_ref (self->source,
	g_binding_group__source_weak_notify,
	self);

	for (i = 0; i < self->lazy_bindings->len; i++)
	{
	LazyBinding *lazy_binding;

	lazy_binding = g_ptr_array_index (self->lazy_bindings, i);
	g_binding_group_connect (self, lazy_binding);
	}
	}

	notify = TRUE;

	unlock:
	g_mutex_unlock (&self->mutex);

	if (notify)
	g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_SOURCE]);
	}

	static void
	g_binding_group_bind_helper (GBindingGroup *self,
	const gchar *source_property,
	gpointer target,
	const gchar *target_property,
	GBindingFlags flags,
	gpointer transform_to,
	gpointer transform_from,
	gpointer user_data,
	GDestroyNotify user_data_destroy,
	gboolean using_closures)
	{
	LazyBinding *lazy_binding;

	g_return_if_fail (G_IS_BINDING_GROUP (self));
	g_return_if_fail (source_property != NULL);
	g_return_if_fail (self->source == NULL \|\|
	g_object_class_find_property (G_OBJECT_GET_CLASS (self->source),
	source_property) != NULL);
	g_return_if_fail (G_IS_OBJECT (target));
	g_return_if_fail (target_property != NULL);
	g_return_if_fail (g_object_class_find_property (G_OBJECT_GET_CLASS (target),
	target_property) != NULL);
	g_return_if_fail (target != (gpointer) self \|\|
	strcmp (source_property, target_property) != 0);

	g_mutex_lock (&self->mutex);

	lazy_binding = g_slice_new0 (LazyBinding);
	lazy_binding->group = self;
	lazy_binding->source_property = g_intern_string (source_property);
	lazy_binding->target_property = g_intern_string (target_property);
	lazy_binding->target = target;
	lazy_binding->binding_flags = flags \| G_BINDING_SYNC_CREATE;
	lazy_binding->user_data = user_data;
	lazy_binding->user_data_destroy = user_data_destroy;
	lazy_binding->transform_to = transform_to;
	lazy_binding->transform_from = transform_from;

	if (using_closures)
	{
	lazy_binding->using_closures = TRUE;

	if (transform_to != NULL)
	g_closure_sink (g_closure_ref (transform_to));

	if (transform_from != NULL)
	g_closure_sink (g_closure_ref (transform_from));
	}

	g_object_weak_ref (target,
	g_binding_group__target_weak_notify,
	self);

	g_ptr_array_add (self->lazy_bindings, lazy_binding);

	if (self->source != NULL)
	g_binding_group_connect (self, lazy_binding);

	g_mutex_unlock (&self->mutex);
	}

	/**
	* g_binding_group_bind:
	* @self: the #GBindingGroup
	* @source_property: the property on the source to bind
	* @target: (type GObject) (transfer none) (not nullable): the target #GObject
	* @target_property: the property on @target to bind
	* @flags: the flags used to create the #GBinding
	*
	* Creates a binding between @source_property on the source object
	* and @target_property on @target. Whenever the @source_property
	* is changed the @target_property is updated using the same value.
	* The binding flag %G_BINDING_SYNC_CREATE is automatically specified.
	*
	* See g_object_bind_property() for more information.
	*
	* Since: 2.72
	*/
	void
	g_binding_group_bind (GBindingGroup *self,
	const gchar *source_property,
	gpointer target,
	const gchar *target_property,
	GBindingFlags flags)
	{
	g_binding_group_bind_full (self, source_property,
	target, target_property,
	flags,
	NULL, NULL,
	NULL, NULL);
	}

	/**
	* g_binding_group_bind_full:
	* @self: the #GBindingGroup
	* @source_property: the property on the source to bind
	* @target: (type GObject) (transfer none) (not nullable): the target #GObject
	* @target_property: the property on @target to bind
	* @flags: the flags used to create the #GBinding
	* @transform_to: (scope notified) (nullable): the transformation function
	* from the source object to the @target, or %NULL to use the default
	* @transform_from: (scope notified) (nullable): the transformation function
	* from the @target to the source object, or %NULL to use the default
	* @user_data: custom data to be passed to the transformation
	* functions, or %NULL
	* @user_data_destroy: function to be called when disposing the binding,
	* to free the resources used by the transformation functions
	*
	* Creates a binding between @source_property on the source object and
	* @target_property on @target, allowing you to set the transformation
	* functions to be used by the binding. The binding flag
	* %G_BINDING_SYNC_CREATE is automatically specified.
	*
	* See g_object_bind_property_full() for more information.
	*
	* Since: 2.72
	*/
	void
	g_binding_group_bind_full (GBindingGroup *self,
	const gchar *source_property,
	gpointer target,
	const gchar *target_property,
	GBindingFlags flags,
	GBindingTransformFunc transform_to,
	GBindingTransformFunc transform_from,
	gpointer user_data,
	GDestroyNotify user_data_destroy)
	{
	g_binding_group_bind_helper (self, source_property,
	target, target_property,
	flags,
	transform_to, transform_from,
	user_data, user_data_destroy,
	FALSE);
	}

	/**
	* g_binding_group_bind_with_closures: (rename-to g_binding_group_bind_full)
	* @self: the #GBindingGroup
	* @source_property: the property on the source to bind
	* @target: (type GObject) (transfer none) (not nullable): the target #GObject
	* @target_property: the property on @target to bind
	* @flags: the flags used to create the #GBinding
	* @transform_to: (nullable) (transfer none): a #GClosure wrapping the
	* transformation function from the source object to the @target,
	* or %NULL to use the default
	* @transform_from: (nullable) (transfer none): a #GClosure wrapping the
	* transformation function from the @target to the source object,
	* or %NULL to use the default
	*
	* Creates a binding between @source_property on the source object and
	* @target_property on @target, allowing you to set the transformation
	* functions to be used by the binding. The binding flag
	* %G_BINDING_SYNC_CREATE is automatically specified.
	*
	* This function is the language bindings friendly version of
	* g_binding_group_bind_property_full(), using #GClosures
	* instead of function pointers.
	*
	* See g_object_bind_property_with_closures() for more information.
	*
	* Since: 2.72
	*/
	void
	g_binding_group_bind_with_closures (GBindingGroup *self,
	const gchar *source_property,
	gpointer target,
	const gchar *target_property,
	GBindingFlags flags,
	GClosure *transform_to,
	GClosure *transform_from)
	{
	g_binding_group_bind_helper (self, source_property,
	target, target_property,
	flags,
	transform_to, transform_from,
	NULL, NULL,
	TRUE);
	}