glib/gobject/gbindinggroup.c

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/* 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"
/**
* GBindingGroup:
*
* `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 [method@GObject.BindingGroup.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:
*
* The source object used for binding properties.
*
* Since: 2.72
*/
properties[PROP_SOURCE] =
g_param_spec_object ("source", NULL, NULL,
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);
}