glib/gobject/gobject.c
Owen Taylor 68e49c7811 Order refs/unrefs so setting the same object back is safe. (#112861,
Fri May 30 14:42:24 2003  Owen Taylor  <otaylor@redhat.com>

        * gobject.c (g_value_set_object): Order refs/unrefs
        so setting the same object back is safe. (#112861,
        Morten Welinder)
2003-05-30 18:44:57 +00:00

1737 lines
46 KiB
C

/* GObject - GLib Type, Object, Parameter and Signal Library
* Copyright (C) 1998-1999, 2000-2001 Tim Janik and Red Hat, Inc.
*
* 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 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, write to the
* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include "gobject.h"
/*
* MT safe
*/
#include "gvaluecollector.h"
#include "gsignal.h"
#include "gparamspecs.h"
#include "gvaluetypes.h"
#include "gobjectnotifyqueue.c"
#include <string.h>
#include <signal.h>
#define PREALLOC_CPARAMS (8)
/* --- macros --- */
#define PARAM_SPEC_PARAM_ID(pspec) ((pspec)->param_id)
#define PARAM_SPEC_SET_PARAM_ID(pspec, id) ((pspec)->param_id = (id))
/* --- signals --- */
enum {
NOTIFY,
LAST_SIGNAL
};
/* --- properties --- */
enum {
PROP_NONE
};
/* --- prototypes --- */
static void g_object_base_class_init (GObjectClass *class);
static void g_object_base_class_finalize (GObjectClass *class);
static void g_object_do_class_init (GObjectClass *class);
static void g_object_init (GObject *object);
static GObject* g_object_constructor (GType type,
guint n_construct_properties,
GObjectConstructParam *construct_params);
static void g_object_last_unref (GObject *object);
static void g_object_real_dispose (GObject *object);
static void g_object_finalize (GObject *object);
static void g_object_do_set_property (GObject *object,
guint property_id,
const GValue *value,
GParamSpec *pspec);
static void g_object_do_get_property (GObject *object,
guint property_id,
GValue *value,
GParamSpec *pspec);
static void g_value_object_init (GValue *value);
static void g_value_object_free_value (GValue *value);
static void g_value_object_copy_value (const GValue *src_value,
GValue *dest_value);
static void g_value_object_transform_value (const GValue *src_value,
GValue *dest_value);
static gpointer g_value_object_peek_pointer (const GValue *value);
static gchar* g_value_object_collect_value (GValue *value,
guint n_collect_values,
GTypeCValue *collect_values,
guint collect_flags);
static gchar* g_value_object_lcopy_value (const GValue *value,
guint n_collect_values,
GTypeCValue *collect_values,
guint collect_flags);
static void g_object_dispatch_properties_changed (GObject *object,
guint n_pspecs,
GParamSpec **pspecs);
static inline void object_get_property (GObject *object,
GParamSpec *pspec,
GValue *value);
static inline void object_set_property (GObject *object,
GParamSpec *pspec,
const GValue *value,
GObjectNotifyQueue *nqueue);
/* --- variables --- */
static GQuark quark_closure_array = 0;
static GQuark quark_weak_refs = 0;
static GParamSpecPool *pspec_pool = NULL;
static GObjectNotifyContext property_notify_context = { 0, };
static gulong gobject_signals[LAST_SIGNAL] = { 0, };
/* --- functions --- */
#ifdef G_ENABLE_DEBUG
#define IF_DEBUG(debug_type) if (_g_type_debug_flags & G_TYPE_DEBUG_ ## debug_type)
G_LOCK_DEFINE_STATIC (debug_objects);
static volatile GObject *g_trap_object_ref = NULL;
static guint debug_objects_count = 0;
static GHashTable *debug_objects_ht = NULL;
static void
debug_objects_foreach (gpointer key,
gpointer value,
gpointer user_data)
{
GObject *object = value;
g_message ("[%p] stale %s\tref_count=%u",
object,
G_OBJECT_TYPE_NAME (object),
object->ref_count);
}
static void
debug_objects_atexit (void)
{
IF_DEBUG (OBJECTS)
{
G_LOCK (debug_objects);
g_message ("stale GObjects: %u", debug_objects_count);
g_hash_table_foreach (debug_objects_ht, debug_objects_foreach, NULL);
G_UNLOCK (debug_objects);
}
}
#endif /* G_ENABLE_DEBUG */
void
g_object_type_init (void) /* sync with gtype.c */
{
static gboolean initialized = FALSE;
static const GTypeFundamentalInfo finfo = {
G_TYPE_FLAG_CLASSED | G_TYPE_FLAG_INSTANTIATABLE | G_TYPE_FLAG_DERIVABLE | G_TYPE_FLAG_DEEP_DERIVABLE,
};
static GTypeInfo info = {
sizeof (GObjectClass),
(GBaseInitFunc) g_object_base_class_init,
(GBaseFinalizeFunc) g_object_base_class_finalize,
(GClassInitFunc) g_object_do_class_init,
NULL /* class_destroy */,
NULL /* class_data */,
sizeof (GObject),
0 /* n_preallocs */,
(GInstanceInitFunc) g_object_init,
NULL, /* value_table */
};
static const GTypeValueTable value_table = {
g_value_object_init, /* value_init */
g_value_object_free_value, /* value_free */
g_value_object_copy_value, /* value_copy */
g_value_object_peek_pointer, /* value_peek_pointer */
"p", /* collect_format */
g_value_object_collect_value, /* collect_value */
"p", /* lcopy_format */
g_value_object_lcopy_value, /* lcopy_value */
};
GType type;
g_return_if_fail (initialized == FALSE);
initialized = TRUE;
/* G_TYPE_OBJECT
*/
info.value_table = &value_table;
type = g_type_register_fundamental (G_TYPE_OBJECT, "GObject", &info, &finfo, 0);
g_assert (type == G_TYPE_OBJECT);
g_value_register_transform_func (G_TYPE_OBJECT, G_TYPE_OBJECT, g_value_object_transform_value);
#ifdef G_ENABLE_DEBUG
IF_DEBUG (OBJECTS)
{
debug_objects_ht = g_hash_table_new (g_direct_hash, NULL);
g_atexit (debug_objects_atexit);
}
#endif /* G_ENABLE_DEBUG */
}
static void
g_object_base_class_init (GObjectClass *class)
{
GObjectClass *pclass = g_type_class_peek_parent (class);
/* reset instance specific fields and methods that don't get inherited */
class->construct_properties = pclass ? g_slist_copy (pclass->construct_properties) : NULL;
class->get_property = NULL;
class->set_property = NULL;
}
static void
g_object_base_class_finalize (GObjectClass *class)
{
GList *list, *node;
_g_signals_destroy (G_OBJECT_CLASS_TYPE (class));
g_slist_free (class->construct_properties);
class->construct_properties = NULL;
list = g_param_spec_pool_list_owned (pspec_pool, G_OBJECT_CLASS_TYPE (class));
for (node = list; node; node = node->next)
{
GParamSpec *pspec = node->data;
g_param_spec_pool_remove (pspec_pool, pspec);
PARAM_SPEC_SET_PARAM_ID (pspec, 0);
g_param_spec_unref (pspec);
}
g_list_free (list);
}
static void
g_object_notify_dispatcher (GObject *object,
guint n_pspecs,
GParamSpec **pspecs)
{
G_OBJECT_GET_CLASS (object)->dispatch_properties_changed (object, n_pspecs, pspecs);
}
static void
g_object_do_class_init (GObjectClass *class)
{
/* read the comment about typedef struct CArray; on why not to change this quark */
quark_closure_array = g_quark_from_static_string ("GObject-closure-array");
quark_weak_refs = g_quark_from_static_string ("GObject-weak-references");
pspec_pool = g_param_spec_pool_new (TRUE);
property_notify_context.quark_notify_queue = g_quark_from_static_string ("GObject-notify-queue");
property_notify_context.dispatcher = g_object_notify_dispatcher;
class->constructor = g_object_constructor;
class->set_property = g_object_do_set_property;
class->get_property = g_object_do_get_property;
class->dispose = g_object_real_dispose;
class->finalize = g_object_finalize;
class->dispatch_properties_changed = g_object_dispatch_properties_changed;
class->notify = NULL;
gobject_signals[NOTIFY] =
g_signal_new ("notify",
G_TYPE_FROM_CLASS (class),
G_SIGNAL_RUN_FIRST | G_SIGNAL_NO_RECURSE | G_SIGNAL_DETAILED | G_SIGNAL_NO_HOOKS,
G_STRUCT_OFFSET (GObjectClass, notify),
NULL, NULL,
g_cclosure_marshal_VOID__PARAM,
G_TYPE_NONE,
1, G_TYPE_PARAM);
}
void
g_object_class_install_property (GObjectClass *class,
guint property_id,
GParamSpec *pspec)
{
g_return_if_fail (G_IS_OBJECT_CLASS (class));
g_return_if_fail (G_IS_PARAM_SPEC (pspec));
if (pspec->flags & G_PARAM_WRITABLE)
g_return_if_fail (class->set_property != NULL);
if (pspec->flags & G_PARAM_READABLE)
g_return_if_fail (class->get_property != NULL);
g_return_if_fail (property_id > 0);
g_return_if_fail (PARAM_SPEC_PARAM_ID (pspec) == 0); /* paranoid */
if (pspec->flags & G_PARAM_CONSTRUCT)
g_return_if_fail ((pspec->flags & G_PARAM_CONSTRUCT_ONLY) == 0);
if (pspec->flags & (G_PARAM_CONSTRUCT | G_PARAM_CONSTRUCT_ONLY))
g_return_if_fail (pspec->flags & G_PARAM_WRITABLE);
if (g_param_spec_pool_lookup (pspec_pool, pspec->name, G_OBJECT_CLASS_TYPE (class), FALSE))
{
g_warning (G_STRLOC ": class `%s' already contains a property named `%s'",
G_OBJECT_CLASS_NAME (class),
pspec->name);
return;
}
g_param_spec_ref (pspec);
g_param_spec_sink (pspec);
PARAM_SPEC_SET_PARAM_ID (pspec, property_id);
g_param_spec_pool_insert (pspec_pool, pspec, G_OBJECT_CLASS_TYPE (class));
if (pspec->flags & (G_PARAM_CONSTRUCT | G_PARAM_CONSTRUCT_ONLY))
class->construct_properties = g_slist_prepend (class->construct_properties, pspec);
/* for property overrides of construct poperties, we have to get rid
* of the overidden inherited construct property
*/
pspec = g_param_spec_pool_lookup (pspec_pool, pspec->name, g_type_parent (G_OBJECT_CLASS_TYPE (class)), TRUE);
if (pspec && pspec->flags & (G_PARAM_CONSTRUCT | G_PARAM_CONSTRUCT_ONLY))
class->construct_properties = g_slist_remove (class->construct_properties, pspec);
}
GParamSpec*
g_object_class_find_property (GObjectClass *class,
const gchar *property_name)
{
g_return_val_if_fail (G_IS_OBJECT_CLASS (class), NULL);
g_return_val_if_fail (property_name != NULL, NULL);
return g_param_spec_pool_lookup (pspec_pool,
property_name,
G_OBJECT_CLASS_TYPE (class),
TRUE);
}
GParamSpec** /* free result */
g_object_class_list_properties (GObjectClass *class,
guint *n_properties_p)
{
GParamSpec **pspecs;
guint n;
g_return_val_if_fail (G_IS_OBJECT_CLASS (class), NULL);
pspecs = g_param_spec_pool_list (pspec_pool,
G_OBJECT_CLASS_TYPE (class),
&n);
if (n_properties_p)
*n_properties_p = n;
return pspecs;
}
static void
g_object_init (GObject *object)
{
object->ref_count = 1;
g_datalist_init (&object->qdata);
/* freeze object's notification queue, g_object_newv() preserves pairedness */
g_object_notify_queue_freeze (object, &property_notify_context);
#ifdef G_ENABLE_DEBUG
IF_DEBUG (OBJECTS)
{
G_LOCK (debug_objects);
debug_objects_count++;
g_hash_table_insert (debug_objects_ht, object, object);
G_UNLOCK (debug_objects);
}
#endif /* G_ENABLE_DEBUG */
}
static void
g_object_do_set_property (GObject *object,
guint property_id,
const GValue *value,
GParamSpec *pspec)
{
switch (property_id)
{
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
break;
}
}
static void
g_object_do_get_property (GObject *object,
guint property_id,
GValue *value,
GParamSpec *pspec)
{
switch (property_id)
{
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
break;
}
}
static void
g_object_real_dispose (GObject *object)
{
guint ref_count;
g_signal_handlers_destroy (object);
g_datalist_id_set_data (&object->qdata, quark_closure_array, NULL);
/* yes, temporarily altering the ref_count is hackish, but that
* enforces people not jerking around with weak_ref notifiers
*/
ref_count = object->ref_count;
object->ref_count = 0;
g_datalist_id_set_data (&object->qdata, quark_weak_refs, NULL);
object->ref_count = ref_count;
}
static void
g_object_finalize (GObject *object)
{
g_datalist_clear (&object->qdata);
#ifdef G_ENABLE_DEBUG
IF_DEBUG (OBJECTS)
{
G_LOCK (debug_objects);
g_assert (g_hash_table_lookup (debug_objects_ht, object) == object);
g_hash_table_remove (debug_objects_ht, object);
debug_objects_count--;
G_UNLOCK (debug_objects);
}
#endif /* G_ENABLE_DEBUG */
}
static void
g_object_last_unref (GObject *object)
{
g_return_if_fail (object->ref_count > 0);
if (object->ref_count == 1) /* may have been re-referenced meanwhile */
G_OBJECT_GET_CLASS (object)->dispose (object);
#ifdef G_ENABLE_DEBUG
if (g_trap_object_ref == object)
G_BREAKPOINT ();
#endif /* G_ENABLE_DEBUG */
object->ref_count -= 1;
if (object->ref_count == 0) /* may have been re-referenced meanwhile */
{
g_signal_handlers_destroy (object);
g_datalist_id_set_data (&object->qdata, quark_weak_refs, NULL);
G_OBJECT_GET_CLASS (object)->finalize (object);
#ifdef G_ENABLE_DEBUG
IF_DEBUG (OBJECTS)
{
/* catch objects not chaining finalize handlers */
G_LOCK (debug_objects);
g_assert (g_hash_table_lookup (debug_objects_ht, object) == NULL);
G_UNLOCK (debug_objects);
}
#endif /* G_ENABLE_DEBUG */
g_type_free_instance ((GTypeInstance*) object);
}
}
static void
g_object_dispatch_properties_changed (GObject *object,
guint n_pspecs,
GParamSpec **pspecs)
{
guint i;
for (i = 0; i < n_pspecs; i++)
g_signal_emit (object, gobject_signals[NOTIFY], g_quark_from_string (pspecs[i]->name), pspecs[i]);
}
void
g_object_run_dispose (GObject *object)
{
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (object->ref_count > 0);
g_object_ref (object);
G_OBJECT_GET_CLASS (object)->dispose (object);
g_object_unref (object);
}
void
g_object_freeze_notify (GObject *object)
{
g_return_if_fail (G_IS_OBJECT (object));
if (!object->ref_count)
return;
g_object_ref (object);
g_object_notify_queue_freeze (object, &property_notify_context);
g_object_unref (object);
}
void
g_object_notify (GObject *object,
const gchar *property_name)
{
GParamSpec *pspec;
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (property_name != NULL);
if (!object->ref_count)
return;
g_object_ref (object);
pspec = g_param_spec_pool_lookup (pspec_pool,
property_name,
G_OBJECT_TYPE (object),
TRUE);
if (!pspec)
g_warning ("%s: object class `%s' has no property named `%s'",
G_STRLOC,
G_OBJECT_TYPE_NAME (object),
property_name);
else
{
GObjectNotifyQueue *nqueue = g_object_notify_queue_freeze (object, &property_notify_context);
g_object_notify_queue_add (object, nqueue, pspec);
g_object_notify_queue_thaw (object, nqueue);
}
g_object_unref (object);
}
void
g_object_thaw_notify (GObject *object)
{
GObjectNotifyQueue *nqueue;
g_return_if_fail (G_IS_OBJECT (object));
if (!object->ref_count)
return;
g_object_ref (object);
nqueue = g_object_notify_queue_from_object (object, &property_notify_context);
if (!nqueue || !nqueue->freeze_count)
g_warning (G_STRLOC ": property-changed notification for %s(%p) is not frozen",
G_OBJECT_TYPE_NAME (object), object);
else
g_object_notify_queue_thaw (object, nqueue);
g_object_unref (object);
}
static inline void
object_get_property (GObject *object,
GParamSpec *pspec,
GValue *value)
{
GObjectClass *class = g_type_class_peek (pspec->owner_type);
class->get_property (object, PARAM_SPEC_PARAM_ID (pspec), value, pspec);
}
static inline void
object_set_property (GObject *object,
GParamSpec *pspec,
const GValue *value,
GObjectNotifyQueue *nqueue)
{
GValue tmp_value = { 0, };
GObjectClass *class = g_type_class_peek (pspec->owner_type);
/* provide a copy to work from, convert (if necessary) and validate */
g_value_init (&tmp_value, G_PARAM_SPEC_VALUE_TYPE (pspec));
if (!g_value_transform (value, &tmp_value))
g_warning ("unable to set property `%s' of type `%s' from value of type `%s'",
pspec->name,
g_type_name (G_PARAM_SPEC_VALUE_TYPE (pspec)),
G_VALUE_TYPE_NAME (value));
else if (g_param_value_validate (pspec, &tmp_value) && !(pspec->flags & G_PARAM_LAX_VALIDATION))
{
gchar *contents = g_strdup_value_contents (value);
g_warning ("value \"%s\" of type `%s' is invalid for property `%s' of type `%s'",
contents,
G_VALUE_TYPE_NAME (value),
pspec->name,
g_type_name (G_PARAM_SPEC_VALUE_TYPE (pspec)));
g_free (contents);
}
else
{
class->set_property (object, PARAM_SPEC_PARAM_ID (pspec), &tmp_value, pspec);
g_object_notify_queue_add (object, nqueue, pspec);
}
g_value_unset (&tmp_value);
}
gpointer
g_object_new (GType object_type,
const gchar *first_property_name,
...)
{
GObject *object;
va_list var_args;
g_return_val_if_fail (G_TYPE_IS_OBJECT (object_type), NULL);
va_start (var_args, first_property_name);
object = g_object_new_valist (object_type, first_property_name, var_args);
va_end (var_args);
return object;
}
gpointer
g_object_newv (GType object_type,
guint n_parameters,
GParameter *parameters)
{
GObjectConstructParam *cparams, *oparams;
GObjectNotifyQueue *nqueue;
GObject *object;
GObjectClass *class;
GSList *slist;
guint n_total_cparams = 0, n_cparams = 0, n_oparams = 0, n_cvalues;
GValue *cvalues;
GList *clist = NULL;
guint i;
g_return_val_if_fail (G_TYPE_IS_OBJECT (object_type), NULL);
class = g_type_class_ref (object_type);
for (slist = class->construct_properties; slist; slist = slist->next)
{
clist = g_list_prepend (clist, slist->data);
n_total_cparams += 1;
}
/* collect parameters, sort into construction and normal ones */
oparams = g_new (GObjectConstructParam, n_parameters);
cparams = g_new (GObjectConstructParam, n_total_cparams);
for (i = 0; i < n_parameters; i++)
{
GValue *value = &parameters[i].value;
GParamSpec *pspec = g_param_spec_pool_lookup (pspec_pool,
parameters[i].name,
object_type,
TRUE);
if (!pspec)
{
g_warning ("%s: object class `%s' has no property named `%s'",
G_STRLOC,
g_type_name (object_type),
parameters[i].name);
continue;
}
if (!(pspec->flags & G_PARAM_WRITABLE))
{
g_warning ("%s: property `%s' of object class `%s' is not writable",
G_STRLOC,
pspec->name,
g_type_name (object_type));
continue;
}
if (pspec->flags & (G_PARAM_CONSTRUCT | G_PARAM_CONSTRUCT_ONLY))
{
GList *list = g_list_find (clist, pspec);
if (!list)
{
g_warning (G_STRLOC ": construct property \"%s\" for object `%s' can't be set twice",
pspec->name, g_type_name (object_type));
continue;
}
cparams[n_cparams].pspec = pspec;
cparams[n_cparams].value = value;
n_cparams++;
if (!list->prev)
clist = list->next;
else
list->prev->next = list->next;
if (list->next)
list->next->prev = list->prev;
g_list_free_1 (list);
}
else
{
oparams[n_oparams].pspec = pspec;
oparams[n_oparams].value = value;
n_oparams++;
}
}
/* set remaining construction properties to default values */
n_cvalues = n_total_cparams - n_cparams;
cvalues = g_new (GValue, n_cvalues);
while (clist)
{
GList *tmp = clist->next;
GParamSpec *pspec = clist->data;
GValue *value = cvalues + n_total_cparams - n_cparams - 1;
value->g_type = 0;
g_value_init (value, G_PARAM_SPEC_VALUE_TYPE (pspec));
g_param_value_set_default (pspec, value);
cparams[n_cparams].pspec = pspec;
cparams[n_cparams].value = value;
n_cparams++;
g_list_free_1 (clist);
clist = tmp;
}
/* construct object from construction parameters */
object = class->constructor (object_type, n_total_cparams, cparams);
/* free construction values */
g_free (cparams);
while (n_cvalues--)
g_value_unset (cvalues + n_cvalues);
g_free (cvalues);
/* release g_object_init() notification queue freeze_count */
nqueue = g_object_notify_queue_freeze (object, &property_notify_context);
g_object_notify_queue_thaw (object, nqueue);
/* set remaining properties */
for (i = 0; i < n_oparams; i++)
object_set_property (object, oparams[i].pspec, oparams[i].value, nqueue);
g_free (oparams);
g_type_class_unref (class);
/* release our own freeze count and handle notifications */
g_object_notify_queue_thaw (object, nqueue);
return object;
}
GObject*
g_object_new_valist (GType object_type,
const gchar *first_property_name,
va_list var_args)
{
GObjectClass *class;
GParameter *params;
const gchar *name;
GObject *object;
guint n_params = 0, n_alloced_params = 16;
g_return_val_if_fail (G_TYPE_IS_OBJECT (object_type), NULL);
if (!first_property_name)
return g_object_newv (object_type, 0, NULL);
class = g_type_class_ref (object_type);
params = g_new (GParameter, n_alloced_params);
name = first_property_name;
while (name)
{
gchar *error = NULL;
GParamSpec *pspec = g_param_spec_pool_lookup (pspec_pool,
name,
object_type,
TRUE);
if (!pspec)
{
g_warning ("%s: object class `%s' has no property named `%s'",
G_STRLOC,
g_type_name (object_type),
name);
break;
}
if (n_params >= n_alloced_params)
{
n_alloced_params += 16;
params = g_renew (GParameter, params, n_alloced_params);
}
params[n_params].name = name;
params[n_params].value.g_type = 0;
g_value_init (&params[n_params].value, G_PARAM_SPEC_VALUE_TYPE (pspec));
G_VALUE_COLLECT (&params[n_params].value, var_args, 0, &error);
if (error)
{
g_warning ("%s: %s", G_STRLOC, error);
g_free (error);
/* we purposely leak the value here, it might not be
* in a sane state if an error condition occoured
*/
break;
}
n_params++;
name = va_arg (var_args, gchar*);
}
object = g_object_newv (object_type, n_params, params);
while (n_params--)
g_value_unset (&params[n_params].value);
g_free (params);
g_type_class_unref (class);
return object;
}
static GObject*
g_object_constructor (GType type,
guint n_construct_properties,
GObjectConstructParam *construct_params)
{
GObject *object;
/* create object */
object = (GObject*) g_type_create_instance (type);
/* set construction parameters */
if (n_construct_properties)
{
GObjectNotifyQueue *nqueue = g_object_notify_queue_freeze (object, &property_notify_context);
/* set construct properties */
while (n_construct_properties--)
{
GValue *value = construct_params->value;
GParamSpec *pspec = construct_params->pspec;
construct_params++;
object_set_property (object, pspec, value, nqueue);
}
g_object_notify_queue_thaw (object, nqueue);
/* the notification queue is still frozen from g_object_init(), so
* we don't need to handle it here, g_object_newv() takes
* care of that
*/
}
return object;
}
void
g_object_set_valist (GObject *object,
const gchar *first_property_name,
va_list var_args)
{
GObjectNotifyQueue *nqueue;
const gchar *name;
g_return_if_fail (G_IS_OBJECT (object));
g_object_ref (object);
nqueue = g_object_notify_queue_freeze (object, &property_notify_context);
name = first_property_name;
while (name)
{
GValue value = { 0, };
GParamSpec *pspec;
gchar *error = NULL;
pspec = g_param_spec_pool_lookup (pspec_pool,
name,
G_OBJECT_TYPE (object),
TRUE);
if (!pspec)
{
g_warning ("%s: object class `%s' has no property named `%s'",
G_STRLOC,
G_OBJECT_TYPE_NAME (object),
name);
break;
}
if (!(pspec->flags & G_PARAM_WRITABLE))
{
g_warning ("%s: property `%s' of object class `%s' is not writable",
G_STRLOC,
pspec->name,
G_OBJECT_TYPE_NAME (object));
break;
}
g_value_init (&value, G_PARAM_SPEC_VALUE_TYPE (pspec));
G_VALUE_COLLECT (&value, var_args, 0, &error);
if (error)
{
g_warning ("%s: %s", G_STRLOC, error);
g_free (error);
/* we purposely leak the value here, it might not be
* in a sane state if an error condition occoured
*/
break;
}
object_set_property (object, pspec, &value, nqueue);
g_value_unset (&value);
name = va_arg (var_args, gchar*);
}
g_object_notify_queue_thaw (object, nqueue);
g_object_unref (object);
}
void
g_object_get_valist (GObject *object,
const gchar *first_property_name,
va_list var_args)
{
const gchar *name;
g_return_if_fail (G_IS_OBJECT (object));
g_object_ref (object);
name = first_property_name;
while (name)
{
GValue value = { 0, };
GParamSpec *pspec;
gchar *error;
pspec = g_param_spec_pool_lookup (pspec_pool,
name,
G_OBJECT_TYPE (object),
TRUE);
if (!pspec)
{
g_warning ("%s: object class `%s' has no property named `%s'",
G_STRLOC,
G_OBJECT_TYPE_NAME (object),
name);
break;
}
if (!(pspec->flags & G_PARAM_READABLE))
{
g_warning ("%s: property `%s' of object class `%s' is not readable",
G_STRLOC,
pspec->name,
G_OBJECT_TYPE_NAME (object));
break;
}
g_value_init (&value, G_PARAM_SPEC_VALUE_TYPE (pspec));
object_get_property (object, pspec, &value);
G_VALUE_LCOPY (&value, var_args, 0, &error);
if (error)
{
g_warning ("%s: %s", G_STRLOC, error);
g_free (error);
g_value_unset (&value);
break;
}
g_value_unset (&value);
name = va_arg (var_args, gchar*);
}
g_object_unref (object);
}
void
g_object_set (gpointer _object,
const gchar *first_property_name,
...)
{
GObject *object = _object;
va_list var_args;
g_return_if_fail (G_IS_OBJECT (object));
va_start (var_args, first_property_name);
g_object_set_valist (object, first_property_name, var_args);
va_end (var_args);
}
void
g_object_get (gpointer _object,
const gchar *first_property_name,
...)
{
GObject *object = _object;
va_list var_args;
g_return_if_fail (G_IS_OBJECT (object));
va_start (var_args, first_property_name);
g_object_get_valist (object, first_property_name, var_args);
va_end (var_args);
}
void
g_object_set_property (GObject *object,
const gchar *property_name,
const GValue *value)
{
GObjectNotifyQueue *nqueue;
GParamSpec *pspec;
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (property_name != NULL);
g_return_if_fail (G_IS_VALUE (value));
g_object_ref (object);
nqueue = g_object_notify_queue_freeze (object, &property_notify_context);
pspec = g_param_spec_pool_lookup (pspec_pool,
property_name,
G_OBJECT_TYPE (object),
TRUE);
if (!pspec)
g_warning ("%s: object class `%s' has no property named `%s'",
G_STRLOC,
G_OBJECT_TYPE_NAME (object),
property_name);
else
object_set_property (object, pspec, value, nqueue);
g_object_notify_queue_thaw (object, nqueue);
g_object_unref (object);
}
void
g_object_get_property (GObject *object,
const gchar *property_name,
GValue *value)
{
GParamSpec *pspec;
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (property_name != NULL);
g_return_if_fail (G_IS_VALUE (value));
g_object_ref (object);
pspec = g_param_spec_pool_lookup (pspec_pool,
property_name,
G_OBJECT_TYPE (object),
TRUE);
if (!pspec)
g_warning ("%s: object class `%s' has no property named `%s'",
G_STRLOC,
G_OBJECT_TYPE_NAME (object),
property_name);
else
{
GValue *prop_value, tmp_value = { 0, };
/* auto-conversion of the callers value type
*/
if (G_VALUE_TYPE (value) == G_PARAM_SPEC_VALUE_TYPE (pspec))
{
g_value_reset (value);
prop_value = value;
}
else if (!g_value_type_transformable (G_PARAM_SPEC_VALUE_TYPE (pspec), G_VALUE_TYPE (value)))
{
g_warning ("can't retrieve property `%s' of type `%s' as value of type `%s'",
pspec->name,
g_type_name (G_PARAM_SPEC_VALUE_TYPE (pspec)),
G_VALUE_TYPE_NAME (value));
g_object_unref (object);
return;
}
else
{
g_value_init (&tmp_value, G_PARAM_SPEC_VALUE_TYPE (pspec));
prop_value = &tmp_value;
}
object_get_property (object, pspec, prop_value);
if (prop_value != value)
{
g_value_transform (prop_value, value);
g_value_unset (&tmp_value);
}
}
g_object_unref (object);
}
gpointer
g_object_connect (gpointer _object,
const gchar *signal_spec,
...)
{
GObject *object = _object;
va_list var_args;
g_return_val_if_fail (G_IS_OBJECT (object), NULL);
g_return_val_if_fail (object->ref_count > 0, object);
va_start (var_args, signal_spec);
while (signal_spec)
{
GCallback callback = va_arg (var_args, GCallback);
gpointer data = va_arg (var_args, gpointer);
gulong sid;
if (strncmp (signal_spec, "signal::", 8) == 0)
sid = g_signal_connect_data (object, signal_spec + 8,
callback, data, NULL,
0);
else if (strncmp (signal_spec, "object_signal::", 15) == 0)
sid = g_signal_connect_object (object, signal_spec + 15,
callback, data,
0);
else if (strncmp (signal_spec, "swapped_signal::", 16) == 0)
sid = g_signal_connect_data (object, signal_spec + 16,
callback, data, NULL,
G_CONNECT_SWAPPED);
else if (strncmp (signal_spec, "swapped_object_signal::", 23) == 0)
sid = g_signal_connect_object (object, signal_spec + 23,
callback, data,
G_CONNECT_SWAPPED);
else if (strncmp (signal_spec, "signal_after::", 14) == 0)
sid = g_signal_connect_data (object, signal_spec + 14,
callback, data, NULL,
G_CONNECT_AFTER);
else if (strncmp (signal_spec, "object_signal_after::", 21) == 0)
sid = g_signal_connect_object (object, signal_spec + 21,
callback, data,
G_CONNECT_AFTER);
else if (strncmp (signal_spec, "swapped_signal_after::", 22) == 0)
sid = g_signal_connect_data (object, signal_spec + 22,
callback, data, NULL,
G_CONNECT_SWAPPED | G_CONNECT_AFTER);
else if (strncmp (signal_spec, "swapped_object_signal_after::", 29) == 0)
sid = g_signal_connect_object (object, signal_spec + 29,
callback, data,
G_CONNECT_SWAPPED | G_CONNECT_AFTER);
else
{
g_warning ("%s: invalid signal spec \"%s\"", G_STRLOC, signal_spec);
break;
}
signal_spec = va_arg (var_args, gchar*);
}
va_end (var_args);
return object;
}
void
g_object_disconnect (gpointer _object,
const gchar *signal_spec,
...)
{
GObject *object = _object;
va_list var_args;
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (object->ref_count > 0);
va_start (var_args, signal_spec);
while (signal_spec)
{
GCallback callback = va_arg (var_args, GCallback);
gpointer data = va_arg (var_args, gpointer);
guint sid = 0, detail = 0, mask = 0;
if (strncmp (signal_spec, "any_signal::", 12) == 0)
{
signal_spec += 12;
mask = G_SIGNAL_MATCH_ID | G_SIGNAL_MATCH_FUNC | G_SIGNAL_MATCH_DATA;
}
else if (strcmp (signal_spec, "any_signal") == 0)
{
signal_spec += 10;
mask = G_SIGNAL_MATCH_FUNC | G_SIGNAL_MATCH_DATA;
}
else
{
g_warning ("%s: invalid signal spec \"%s\"", G_STRLOC, signal_spec);
break;
}
if ((mask & G_SIGNAL_MATCH_ID) &&
!g_signal_parse_name (signal_spec, G_OBJECT_TYPE (object), &sid, &detail, FALSE))
g_warning ("%s: invalid signal name \"%s\"", G_STRLOC, signal_spec);
else if (!g_signal_handlers_disconnect_matched (object, mask | (detail ? G_SIGNAL_MATCH_DETAIL : 0),
sid, detail,
NULL, (gpointer)callback, data))
g_warning (G_STRLOC ": signal handler %p(%p) is not connected", callback, data);
signal_spec = va_arg (var_args, gchar*);
}
va_end (var_args);
}
typedef struct {
GObject *object;
guint n_weak_refs;
struct {
GWeakNotify notify;
gpointer data;
} weak_refs[1]; /* flexible array */
} WeakRefStack;
static void
weak_refs_notify (gpointer data)
{
WeakRefStack *wstack = data;
guint i;
for (i = 0; i < wstack->n_weak_refs; i++)
wstack->weak_refs[i].notify (wstack->weak_refs[i].data, wstack->object);
g_free (wstack);
}
void
g_object_weak_ref (GObject *object,
GWeakNotify notify,
gpointer data)
{
WeakRefStack *wstack;
guint i;
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (notify != NULL);
g_return_if_fail (object->ref_count >= 1);
wstack = g_datalist_id_remove_no_notify (&object->qdata, quark_weak_refs);
if (wstack)
{
i = wstack->n_weak_refs++;
wstack = g_realloc (wstack, sizeof (*wstack) + sizeof (wstack->weak_refs[0]) * i);
}
else
{
wstack = g_renew (WeakRefStack, NULL, 1);
wstack->object = object;
wstack->n_weak_refs = 1;
i = 0;
}
wstack->weak_refs[i].notify = notify;
wstack->weak_refs[i].data = data;
g_datalist_id_set_data_full (&object->qdata, quark_weak_refs, wstack, weak_refs_notify);
}
void
g_object_weak_unref (GObject *object,
GWeakNotify notify,
gpointer data)
{
WeakRefStack *wstack;
gboolean found_one = FALSE;
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (notify != NULL);
wstack = g_datalist_id_get_data (&object->qdata, quark_weak_refs);
if (wstack)
{
guint i;
for (i = 0; i < wstack->n_weak_refs; i++)
if (wstack->weak_refs[i].notify == notify &&
wstack->weak_refs[i].data == data)
{
found_one = TRUE;
wstack->n_weak_refs -= 1;
if (i != wstack->n_weak_refs)
{
wstack->weak_refs[i].notify = wstack->weak_refs[wstack->n_weak_refs].notify;
wstack->weak_refs[i].data = wstack->weak_refs[wstack->n_weak_refs].data;
}
break;
}
}
if (!found_one)
g_warning (G_STRLOC ": couldn't find weak ref %p(%p)", notify, data);
}
void
g_object_add_weak_pointer (GObject *object,
gpointer *weak_pointer_location)
{
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (weak_pointer_location != NULL);
g_object_weak_ref (object,
(GWeakNotify) g_nullify_pointer,
weak_pointer_location);
}
void
g_object_remove_weak_pointer (GObject *object,
gpointer *weak_pointer_location)
{
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (weak_pointer_location != NULL);
g_object_weak_unref (object,
(GWeakNotify) g_nullify_pointer,
weak_pointer_location);
}
gpointer
g_object_ref (gpointer _object)
{
GObject *object = _object;
g_return_val_if_fail (G_IS_OBJECT (object), NULL);
g_return_val_if_fail (object->ref_count > 0, NULL);
#ifdef G_ENABLE_DEBUG
if (g_trap_object_ref == object)
G_BREAKPOINT ();
#endif /* G_ENABLE_DEBUG */
object->ref_count += 1;
return object;
}
void
g_object_unref (gpointer _object)
{
GObject *object = _object;
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (object->ref_count > 0);
#ifdef G_ENABLE_DEBUG
if (g_trap_object_ref == object)
G_BREAKPOINT ();
#endif /* G_ENABLE_DEBUG */
if (object->ref_count > 1)
object->ref_count -= 1;
else
g_object_last_unref (object);
}
gpointer
g_object_get_qdata (GObject *object,
GQuark quark)
{
g_return_val_if_fail (G_IS_OBJECT (object), NULL);
return quark ? g_datalist_id_get_data (&object->qdata, quark) : NULL;
}
void
g_object_set_qdata (GObject *object,
GQuark quark,
gpointer data)
{
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (quark > 0);
g_datalist_id_set_data (&object->qdata, quark, data);
}
void
g_object_set_qdata_full (GObject *object,
GQuark quark,
gpointer data,
GDestroyNotify destroy)
{
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (quark > 0);
g_datalist_id_set_data_full (&object->qdata, quark, data,
data ? destroy : (GDestroyNotify) NULL);
}
gpointer
g_object_steal_qdata (GObject *object,
GQuark quark)
{
g_return_val_if_fail (G_IS_OBJECT (object), NULL);
g_return_val_if_fail (quark > 0, NULL);
return g_datalist_id_remove_no_notify (&object->qdata, quark);
}
gpointer
g_object_get_data (GObject *object,
const gchar *key)
{
GQuark quark;
g_return_val_if_fail (G_IS_OBJECT (object), NULL);
g_return_val_if_fail (key != NULL, NULL);
quark = g_quark_try_string (key);
return quark ? g_datalist_id_get_data (&object->qdata, quark) : NULL;
}
void
g_object_set_data (GObject *object,
const gchar *key,
gpointer data)
{
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (key != NULL);
g_datalist_id_set_data (&object->qdata, g_quark_from_string (key), data);
}
void
g_object_set_data_full (GObject *object,
const gchar *key,
gpointer data,
GDestroyNotify destroy)
{
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (key != NULL);
g_datalist_id_set_data_full (&object->qdata, g_quark_from_string (key), data,
data ? destroy : (GDestroyNotify) NULL);
}
gpointer
g_object_steal_data (GObject *object,
const gchar *key)
{
GQuark quark;
g_return_val_if_fail (G_IS_OBJECT (object), NULL);
g_return_val_if_fail (key != NULL, NULL);
quark = g_quark_try_string (key);
return quark ? g_datalist_id_remove_no_notify (&object->qdata, quark) : NULL;
}
static void
g_value_object_init (GValue *value)
{
value->data[0].v_pointer = NULL;
}
static void
g_value_object_free_value (GValue *value)
{
if (value->data[0].v_pointer)
g_object_unref (value->data[0].v_pointer);
}
static void
g_value_object_copy_value (const GValue *src_value,
GValue *dest_value)
{
if (src_value->data[0].v_pointer)
dest_value->data[0].v_pointer = g_object_ref (src_value->data[0].v_pointer);
else
dest_value->data[0].v_pointer = NULL;
}
static void
g_value_object_transform_value (const GValue *src_value,
GValue *dest_value)
{
if (src_value->data[0].v_pointer && g_type_is_a (G_OBJECT_TYPE (src_value->data[0].v_pointer), G_VALUE_TYPE (dest_value)))
dest_value->data[0].v_pointer = g_object_ref (src_value->data[0].v_pointer);
else
dest_value->data[0].v_pointer = NULL;
}
static gpointer
g_value_object_peek_pointer (const GValue *value)
{
return value->data[0].v_pointer;
}
static gchar*
g_value_object_collect_value (GValue *value,
guint n_collect_values,
GTypeCValue *collect_values,
guint collect_flags)
{
if (collect_values[0].v_pointer)
{
GObject *object = collect_values[0].v_pointer;
if (object->g_type_instance.g_class == NULL)
return g_strconcat ("invalid unclassed object pointer for value type `",
G_VALUE_TYPE_NAME (value),
"'",
NULL);
else if (!g_value_type_compatible (G_OBJECT_TYPE (object), G_VALUE_TYPE (value)))
return g_strconcat ("invalid object type `",
G_OBJECT_TYPE_NAME (object),
"' for value type `",
G_VALUE_TYPE_NAME (value),
"'",
NULL);
/* never honour G_VALUE_NOCOPY_CONTENTS for ref-counted types */
value->data[0].v_pointer = g_object_ref (object);
}
else
value->data[0].v_pointer = NULL;
return NULL;
}
static gchar*
g_value_object_lcopy_value (const GValue *value,
guint n_collect_values,
GTypeCValue *collect_values,
guint collect_flags)
{
GObject **object_p = collect_values[0].v_pointer;
if (!object_p)
return g_strdup_printf ("value location for `%s' passed as NULL", G_VALUE_TYPE_NAME (value));
if (!value->data[0].v_pointer)
*object_p = NULL;
else if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
*object_p = value->data[0].v_pointer;
else
*object_p = g_object_ref (value->data[0].v_pointer);
return NULL;
}
void
g_value_set_object (GValue *value,
gpointer v_object)
{
GObject *old;
g_return_if_fail (G_VALUE_HOLDS_OBJECT (value));
old = value->data[0].v_pointer;
if (v_object)
{
g_return_if_fail (G_IS_OBJECT (v_object));
g_return_if_fail (g_value_type_compatible (G_OBJECT_TYPE (v_object), G_VALUE_TYPE (value)));
value->data[0].v_pointer = v_object;
g_object_ref (value->data[0].v_pointer);
}
else
value->data[0].v_pointer = NULL;
if (old)
g_object_unref (old);
}
void
g_value_set_object_take_ownership (GValue *value,
gpointer v_object)
{
g_return_if_fail (G_VALUE_HOLDS_OBJECT (value));
if (value->data[0].v_pointer)
{
g_object_unref (value->data[0].v_pointer);
value->data[0].v_pointer = NULL;
}
if (v_object)
{
g_return_if_fail (G_IS_OBJECT (v_object));
g_return_if_fail (g_value_type_compatible (G_OBJECT_TYPE (v_object), G_VALUE_TYPE (value)));
value->data[0].v_pointer = v_object; /* we take over the reference count */
}
}
gpointer
g_value_get_object (const GValue *value)
{
g_return_val_if_fail (G_VALUE_HOLDS_OBJECT (value), NULL);
return value->data[0].v_pointer;
}
GObject*
g_value_dup_object (const GValue *value)
{
g_return_val_if_fail (G_VALUE_HOLDS_OBJECT (value), NULL);
return value->data[0].v_pointer ? g_object_ref (value->data[0].v_pointer) : NULL;
}
gulong
g_signal_connect_object (gpointer instance,
const gchar *detailed_signal,
GCallback c_handler,
gpointer gobject,
GConnectFlags connect_flags)
{
g_return_val_if_fail (G_TYPE_CHECK_INSTANCE (instance), 0);
g_return_val_if_fail (detailed_signal != NULL, 0);
g_return_val_if_fail (c_handler != NULL, 0);
if (gobject)
{
GClosure *closure;
g_return_val_if_fail (G_IS_OBJECT (gobject), 0);
closure = ((connect_flags & G_CONNECT_SWAPPED) ? g_cclosure_new_object_swap : g_cclosure_new_object) (c_handler, gobject);
return g_signal_connect_closure (instance, detailed_signal, closure, connect_flags & G_CONNECT_AFTER);
}
else
return g_signal_connect_data (instance, detailed_signal, c_handler, NULL, NULL, connect_flags);
}
typedef struct {
GObject *object;
guint n_closures;
GClosure *closures[1]; /* flexible array */
} CArray;
/* don't change this structure without supplying an accessor for
* watched closures, e.g.:
* GSList* g_object_list_watched_closures (GObject *object)
* {
* CArray *carray;
* g_return_val_if_fail (G_IS_OBJECT (object), NULL);
* carray = g_object_get_data (object, "GObject-closure-array");
* if (carray)
* {
* GSList *slist = NULL;
* guint i;
* for (i = 0; i < carray->n_closures; i++)
* slist = g_slist_prepend (slist, carray->closures[i]);
* return slist;
* }
* return NULL;
* }
*/
static void
object_remove_closure (gpointer data,
GClosure *closure)
{
GObject *object = data;
CArray *carray = g_object_get_qdata (object, quark_closure_array);
guint i;
for (i = 0; i < carray->n_closures; i++)
if (carray->closures[i] == closure)
{
carray->n_closures--;
if (i < carray->n_closures)
carray->closures[i] = carray->closures[carray->n_closures];
return;
}
g_assert_not_reached ();
}
static void
destroy_closure_array (gpointer data)
{
CArray *carray = data;
GObject *object = carray->object;
guint i, n = carray->n_closures;
for (i = 0; i < n; i++)
{
GClosure *closure = carray->closures[i];
/* removing object_remove_closure() upfront is probably faster than
* letting it fiddle with quark_closure_array which is empty anyways
*/
g_closure_remove_invalidate_notifier (closure, object, object_remove_closure);
g_closure_invalidate (closure);
}
g_free (carray);
}
void
g_object_watch_closure (GObject *object,
GClosure *closure)
{
CArray *carray;
guint i;
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (closure != NULL);
g_return_if_fail (closure->is_invalid == FALSE);
g_return_if_fail (closure->in_marshal == FALSE);
g_return_if_fail (object->ref_count > 0); /* this doesn't work on finalizing objects */
g_closure_add_invalidate_notifier (closure, object, object_remove_closure);
g_closure_add_marshal_guards (closure,
object, (GClosureNotify) g_object_ref,
object, (GClosureNotify) g_object_unref);
carray = g_datalist_id_remove_no_notify (&object->qdata, quark_closure_array);
if (!carray)
{
carray = g_renew (CArray, NULL, 1);
carray->object = object;
carray->n_closures = 1;
i = 0;
}
else
{
i = carray->n_closures++;
carray = g_realloc (carray, sizeof (*carray) + sizeof (carray->closures[0]) * i);
}
carray->closures[i] = closure;
g_datalist_id_set_data_full (&object->qdata, quark_closure_array, carray, destroy_closure_array);
}
GClosure*
g_closure_new_object (guint sizeof_closure,
GObject *object)
{
GClosure *closure;
g_return_val_if_fail (G_IS_OBJECT (object), NULL);
g_return_val_if_fail (object->ref_count > 0, NULL); /* this doesn't work on finalizing objects */
closure = g_closure_new_simple (sizeof_closure, object);
g_object_watch_closure (object, closure);
return closure;
}
GClosure*
g_cclosure_new_object (GCallback callback_func,
GObject *object)
{
GClosure *closure;
g_return_val_if_fail (G_IS_OBJECT (object), NULL);
g_return_val_if_fail (object->ref_count > 0, NULL); /* this doesn't work on finalizing objects */
g_return_val_if_fail (callback_func != NULL, NULL);
closure = g_cclosure_new (callback_func, object, NULL);
g_object_watch_closure (object, closure);
return closure;
}
GClosure*
g_cclosure_new_object_swap (GCallback callback_func,
GObject *object)
{
GClosure *closure;
g_return_val_if_fail (G_IS_OBJECT (object), NULL);
g_return_val_if_fail (object->ref_count > 0, NULL); /* this doesn't work on finalizing objects */
g_return_val_if_fail (callback_func != NULL, NULL);
closure = g_cclosure_new_swap (callback_func, object, NULL);
g_object_watch_closure (object, closure);
return closure;
}