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third-party-mirror/glib/refs/heads/main/./gobject/gobject.c
blob: 111d401b879e283b9e1035d87513c4924467551d [file] [edit]
/* GObject - GLib Type, Object, Parameter and Signal Library
* Copyright (C) 1998-1999, 2000-2001 Tim Janik and Red Hat, Inc.
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*
* 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/>.
*/
/*
* MT safe with regards to reference counting.
*/
#include "config.h"
#include <string.h>
#include <signal.h>
#include "../glib/glib-private.h"
#include "gobject.h"
#include "gtype-private.h"
#include "gvaluecollector.h"
#include "gsignal.h"
#include "gparamspecs.h"
#include "gvaluetypes.h"
#include "gobject_trace.h"
#include "gconstructor.h"
/**
* GObject:
*
* The base object type.
*
* `GObject` is the fundamental type providing the common attributes and
* methods for all object types in GTK, Pango and other libraries
* based on GObject. The `GObject` class provides methods for object
* construction and destruction, property access methods, and signal
* support. Signals are described in detail [here][gobject-Signals].
*
* For a tutorial on implementing a new `GObject` class, see [How to define and
* implement a new GObject](tutorial.html#how-to-define-and-implement-a-new-gobject).
* For a list of naming conventions for GObjects and their methods, see the
* [GType conventions](concepts.html#conventions). For the high-level concepts
* behind GObject, read
* [Instantiatable classed types: Objects](concepts.html#instantiatable-classed-types-objects).
*
* Since GLib 2.72, all `GObject`s are guaranteed to be aligned to at least the
* alignment of the largest basic GLib type (typically this is `guint64` or
* `gdouble`). If you need larger alignment for an element in a `GObject`, you
* should allocate it on the heap (aligned), or arrange for your `GObject` to be
* appropriately padded. This guarantee applies to the `GObject` (or derived)
* struct, the `GObjectClass` (or derived) struct, and any private data allocated
* by `G_ADD_PRIVATE()`.
*/
/* --- macros --- */
#define PARAM_SPEC_PARAM_ID(pspec) ((pspec)->param_id)
#define PARAM_SPEC_SET_PARAM_ID(pspec, id) ((pspec)->param_id = (id))
#define OBJECT_HAS_TOGGLE_REF_FLAG 0x1
#define OBJECT_HAS_TOGGLE_REF(object) \
((g_datalist_get_flags (&(object)->qdata) & OBJECT_HAS_TOGGLE_REF_FLAG) != 0)
#define OBJECT_FLOATING_FLAG 0x2
#define CLASS_HAS_PROPS_FLAG 0x1
#define CLASS_HAS_PROPS(class) \
((class)->flags & CLASS_HAS_PROPS_FLAG)
#define CLASS_HAS_CUSTOM_CONSTRUCTOR(class) \
((class)->constructor != g_object_constructor)
#define CLASS_HAS_CUSTOM_CONSTRUCTED(class) \
((class)->constructed != g_object_constructed)
#define CLASS_HAS_NOTIFY(class) ((class)->notify != NULL)
#define CLASS_HAS_CUSTOM_DISPATCH(class) \
((class)->dispatch_properties_changed != g_object_dispatch_properties_changed)
#define CLASS_NEEDS_NOTIFY(class) \
(CLASS_HAS_NOTIFY(class) || CLASS_HAS_CUSTOM_DISPATCH(class))
#define CLASS_HAS_DERIVED_CLASS_FLAG 0x2
#define CLASS_HAS_DERIVED_CLASS(class) \
((class)->flags & CLASS_HAS_DERIVED_CLASS_FLAG)
/* --- signals --- */
enum {
NOTIFY,
LAST_SIGNAL
};
/* --- properties --- */
enum {
PROP_NONE
};
#define _OPTIONAL_BIT_LOCK 3
#define OPTIONAL_FLAG_IN_CONSTRUCTION (1 << 0)
#define OPTIONAL_FLAG_HAS_SIGNAL_HANDLER (1 << 1) /* Set if object ever had a signal handler */
#define OPTIONAL_FLAG_HAS_NOTIFY_HANDLER (1 << 2) /* Same, specifically for "notify" */
#define OPTIONAL_FLAG_LOCK (1 << 3) /* _OPTIONAL_BIT_LOCK */
#define OPTIONAL_FLAG_EVER_HAD_WEAK_REF (1 << 4) /* whether on the object ever g_weak_ref_set() was called. */
/* We use g_bit_lock(), which only supports one lock per integer.
*
* Hence, while we have locks for different purposes, internally they all
* map to the same bit lock (_OPTIONAL_BIT_LOCK).
*
* This means you cannot take a lock (object_bit_lock()) while already holding
* another bit lock. There is an assert against that with G_ENABLE_DEBUG
* builds (_object_bit_is_locked).
*
* In the past, we had different global mutexes per topic. Now we have one
* per-object mutex for several topics. The downside is that we are not as
* parallel as possible. The alternative would be to add individual locking
* integers to GObjectPrivate. But increasing memory usage for more parallelism
* (per-object!) is not worth it. */
#define OPTIONAL_BIT_LOCK_WEAK_REFS 1
#define OPTIONAL_BIT_LOCK_NOTIFY 2
#define OPTIONAL_BIT_LOCK_TOGGLE_REFS 3
#define OPTIONAL_BIT_LOCK_CLOSURE_ARRAY 4
#if SIZEOF_INT == 4 && GLIB_SIZEOF_VOID_P >= 8
#define HAVE_OPTIONAL_FLAGS_IN_GOBJECT 1
#else
#define HAVE_OPTIONAL_FLAGS_IN_GOBJECT 0
#endif
/* For now we only create a private struct if we don't have optional flags in
* GObject. Currently we don't need it otherwise. In the future we might
* always add a private struct. */
#define HAVE_PRIVATE (!HAVE_OPTIONAL_FLAGS_IN_GOBJECT)
#if HAVE_PRIVATE
typedef struct {
#if !HAVE_OPTIONAL_FLAGS_IN_GOBJECT
guint optional_flags; /* (atomic) */
#endif
} GObjectPrivate;
static int GObject_private_offset;
#endif
typedef struct
{
GTypeInstance g_type_instance;
/*< private >*/
guint ref_count; /* (atomic) */
#if HAVE_OPTIONAL_FLAGS_IN_GOBJECT
guint optional_flags; /* (atomic) */
#endif
GData *qdata;
} GObjectReal;
G_STATIC_ASSERT(sizeof(GObject) == sizeof(GObjectReal));
G_STATIC_ASSERT(G_STRUCT_OFFSET(GObject, ref_count) == G_STRUCT_OFFSET(GObjectReal, ref_count));
G_STATIC_ASSERT(G_STRUCT_OFFSET(GObject, qdata) == G_STRUCT_OFFSET(GObjectReal, qdata));
/* --- 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,
GObjectClass *class);
static GObject* g_object_constructor (GType type,
guint n_construct_properties,
GObjectConstructParam *construct_params);
static void g_object_constructed (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 guint object_floating_flag_handler (GObject *object,
gint job);
static inline void object_set_optional_flags (GObject *object,
guint flags);
static void object_interface_check_properties (gpointer check_data,
gpointer g_iface);
/* --- typedefs --- */
typedef struct _GObjectNotifyQueue GObjectNotifyQueue;
struct _GObjectNotifyQueue
{
GSList *pspecs;
guint16 n_pspecs;
guint16 freeze_count;
};
/* --- variables --- */
static GQuark quark_closure_array = 0;
static GQuark quark_weak_notifies = 0;
static GQuark quark_toggle_refs = 0;
static GQuark quark_notify_queue;
static GParamSpecPool *pspec_pool = NULL;
static gulong gobject_signals[LAST_SIGNAL] = { 0, };
static guint (*floating_flag_handler) (GObject*, gint) = object_floating_flag_handler;
static GQuark quark_weak_locations = 0;
#if HAVE_PRIVATE
G_ALWAYS_INLINE static inline GObjectPrivate *
g_object_get_instance_private (GObject *object)
{
return G_STRUCT_MEMBER_P (object, GObject_private_offset);
}
#endif
G_ALWAYS_INLINE static inline guint *
object_get_optional_flags_p (GObject *object)
{
#if HAVE_OPTIONAL_FLAGS_IN_GOBJECT
return &(((GObjectReal *) object)->optional_flags);
#else
return &g_object_get_instance_private (object)->optional_flags;
#endif
}
/*****************************************************************************/
/* For GWeakRef, we need to take a lock per-object. However, in various cases
* we cannot take a strong reference on the object to keep it alive. So the
* mutex cannot be in the object itself, because when we want to release the
* lock, we can no longer access object.
*
* Instead, the mutex is on the WeakRefData, which is itself ref-counted
* and has a separate lifetime from the object. */
typedef struct
{
/* This is both an atomic ref-count and bit 30 (WEAK_REF_DATA_LOCK_BIT) is
* used for g_bit_lock(). */
gint atomic_field;
guint16 len;
/* Only relevant when len > 1. In that case, it's the allocated size of
* "list.many" array. */
guint16 alloc;
/* Only relevant when len > 0. In that case, either "one" or "many" union
* field is in use. */
union
{
GWeakRef *one;
GWeakRef **many;
} list;
} WeakRefData;
/* We choose bit 30, and not bit 31. Bit 31 would be the sign for gint, so it
* a bit awkward to use. Note that it probably also would work fine.
*
* But 30 is ok, because it still leaves us space for 2^30-1 references, which
* is more than we ever need. */
#define WEAK_REF_DATA_LOCK_BIT 30
static void weak_ref_data_clear_list (WeakRefData *wrdata, GObject *object);
static WeakRefData *
weak_ref_data_ref (WeakRefData *wrdata)
{
gint ref;
#if G_ENABLE_DEBUG
g_assert (wrdata);
#endif
ref = g_atomic_int_add (&wrdata->atomic_field, 1);
#if G_ENABLE_DEBUG
/* Overflow is almost impossible to happen, because the user would need to
* spawn that many operating system threads, that all call
* g_weak_ref_{set,get}() in parallel.
*
* Still, assert in debug mode. */
g_assert (ref < G_MAXINT32);
/* the real ref-count would be the following: */
ref = (ref + 1) & ~(1 << WEAK_REF_DATA_LOCK_BIT);
/* assert that the ref-count is still in the valid range. */
g_assert (ref > 0 && ref < (1 << WEAK_REF_DATA_LOCK_BIT));
#endif
(void) ref;
return wrdata;
}
static void
weak_ref_data_unref (WeakRefData *wrdata)
{
if (!wrdata)
return;
/* Note that we also use WEAK_REF_DATA_LOCK_BIT on "atomic_field" as a bit
* lock. However, we will always keep the @wrdata alive (having a reference)
* while holding a lock (otherwise, we couldn't unlock anymore). Thus, at the
* point when we decrement the ref-count to zero, we surely also have the
* @wrdata unlocked.
*
* This means, using "aomit_field" both as ref-count and the lock bit is
* fine. */
if (!g_atomic_int_dec_and_test (&wrdata->atomic_field))
return;
#if G_ENABLE_DEBUG
/* We expect that the list of weak locations is empty at this point.
* During g_object_unref() (_object_unref_clear_weak_locations()) it
* should have been cleared.
*
* Calling weak_ref_data_clear_list() should be unnecessary. */
g_assert (wrdata->len == 0);
#endif
g_free_sized (wrdata, sizeof (WeakRefData));
}
static void
weak_ref_data_lock (WeakRefData *wrdata)
{
/* Note that while holding a _weak_ref_lock() on the @weak_ref, we MUST not acquire a
* weak_ref_data_lock() on the @wrdata. The other way around! */
if (wrdata)
g_bit_lock (&wrdata->atomic_field, WEAK_REF_DATA_LOCK_BIT);
}
static void
weak_ref_data_unlock (WeakRefData *wrdata)
{
if (wrdata)
g_bit_unlock (&wrdata->atomic_field, WEAK_REF_DATA_LOCK_BIT);
}
static gpointer
weak_ref_data_get_or_create_cb (GQuark key_id,
gpointer *data,
GDestroyNotify *destroy_notify,
gpointer user_data)
{
WeakRefData *wrdata = *data;
GObject *object = user_data;
if (!wrdata)
{
wrdata = g_new (WeakRefData, 1);
/* The initial ref-count is 1. This one is owned by the GData until the
* object gets destroyed.
*
* The WEAK_REF_DATA_LOCK_BIT bit is of course initially unset. */
wrdata->atomic_field = 1;
wrdata->len = 0;
/* Other fields are left uninitialized. They are only considered with a positive @len. */
*data = wrdata;
*destroy_notify = (GDestroyNotify) weak_ref_data_unref;
/* Mark the @object that it was ever involved with GWeakRef. This flag
* will stick until @object gets destroyed, just like the WeakRefData
* also won't be freed for the remainder of the life of @object. */
object_set_optional_flags (object, OPTIONAL_FLAG_EVER_HAD_WEAK_REF);
}
return wrdata;
}
static WeakRefData *
weak_ref_data_get_or_create (GObject *object)
{
if (!object)
return NULL;
return _g_datalist_id_update_atomic (&object->qdata,
quark_weak_locations,
weak_ref_data_get_or_create_cb,
object);
}
static WeakRefData *
weak_ref_data_get (GObject *object)
{
return g_datalist_id_get_data (&object->qdata, quark_weak_locations);
}
static WeakRefData *
weak_ref_data_get_surely (GObject *object)
{
WeakRefData *wrdata;
/* The "surely" part is about that we expect to have a WeakRefData.
*
* Note that once a GObject gets a WeakRefData (during g_weak_ref_set() and
* weak_ref_data_get_or_create()), it sticks and is not freed until the
* object gets destroyed.
*
* Maybe we could release the unused WeakRefData in g_weak_ref_set(), but
* then we would always need to take a reference during weak_ref_data_get().
* That is likely not worth it. */
wrdata = weak_ref_data_get (object);
#if G_ENABLE_DEBUG
g_assert (wrdata);
#endif
return wrdata;
}
static gint32
weak_ref_data_list_find (WeakRefData *wrdata, GWeakRef *weak_ref)
{
if (wrdata->len == 1u)
{
if (wrdata->list.one == weak_ref)
return 0;
}
else
{
guint16 i;
for (i = 0; i < wrdata->len; i++)
{
if (wrdata->list.many[i] == weak_ref)
return i;
}
}
return -1;
}
static gboolean
weak_ref_data_list_add (WeakRefData *wrdata, GWeakRef *weak_ref)
{
if (wrdata->len == 0u)
wrdata->list.one = weak_ref;
else
{
if (wrdata->len == 1u)
{
GWeakRef *weak_ref2 = wrdata->list.one;
wrdata->alloc = 4u;
wrdata->list.many = g_new (GWeakRef *, wrdata->alloc);
wrdata->list.many[0] = weak_ref2;
}
else if (wrdata->len == wrdata->alloc)
{
guint16 alloc;
alloc = wrdata->alloc * 2u;
if (G_UNLIKELY (alloc < wrdata->len))
{
if (wrdata->len == G_MAXUINT16)
return FALSE;
alloc = G_MAXUINT16;
}
wrdata->list.many = g_renew (GWeakRef *, wrdata->list.many, alloc);
wrdata->alloc = alloc;
}
wrdata->list.many[wrdata->len] = weak_ref;
}
wrdata->len++;
return TRUE;
}
static GWeakRef *
weak_ref_data_list_remove (WeakRefData *wrdata, guint16 idx, gboolean allow_shrink)
{
GWeakRef *weak_ref;
#if G_ENABLE_DEBUG
g_assert (idx < wrdata->len);
#endif
wrdata->len--;
if (wrdata->len == 0u)
{
weak_ref = wrdata->list.one;
}
else
{
weak_ref = wrdata->list.many[idx];
if (wrdata->len == 1u)
{
GWeakRef *weak_ref2 = wrdata->list.many[idx == 0 ? 1 : 0];
g_free (wrdata->list.many);
wrdata->list.one = weak_ref2;
}
else
{
wrdata->list.many[idx] = wrdata->list.many[wrdata->len];
if (allow_shrink && G_UNLIKELY (wrdata->len <= wrdata->alloc / 4u))
{
/* Shrink the buffer. When 75% are empty, shrink it to 50%. */
if (wrdata->alloc == G_MAXUINT16)
wrdata->alloc = ((guint32) G_MAXUINT16 + 1u) / 2u;
else
wrdata->alloc /= 2u;
wrdata->list.many = g_renew (GWeakRef *, wrdata->list.many, wrdata->alloc);
}
}
}
return weak_ref;
}
static gboolean
weak_ref_data_has (GObject *object, WeakRefData *wrdata, WeakRefData **out_new_wrdata)
{
WeakRefData *wrdata2;
/* Check whether @object has @wrdata as WeakRefData. Note that an GObject's
* WeakRefData never changes (until destruction, once it's allocated).
*
* If you thus hold a reference to a @wrdata, you can check that the @object
* is still the same as the object where we got the @wrdata originally from.
*
* You couldn't do this check by using pointer equality of the GObject pointers,
* when you cannot hold strong references on the objects involved. Because then
* the object pointer might be dangling (and even destroyed and recreated as another
* object at the same memory location).
*
* Basically, weak_ref_data_has() is to compare for equality of two GObject pointers,
* when we cannot hold a strong reference on both. Instead, we earlier took a reference
* on the @wrdata and compare that instead.
*/
if (!object)
{
/* If @object is NULL, then it does have a NULL @wrdata, and we return
* TRUE in the case. That's a convenient special case for some callers.
*
* In other words, weak_ref_data_has(NULL, NULL, out_new_wrdata) is TRUE.
*/
#if G_ENABLE_DEBUG
g_assert (!out_new_wrdata);
#endif
return !wrdata;
}
if (!wrdata)
{
/* We only call this function with an @object that was previously
* registered as GWeakRef.
*
* That means, our @object will have a wrdata, and the result of the
* evaluation will be %FALSE. */
if (out_new_wrdata)
*out_new_wrdata = weak_ref_data_ref (weak_ref_data_get (object));
#if G_ENABLE_DEBUG
g_assert (out_new_wrdata
? *out_new_wrdata
: weak_ref_data_get (object));
#endif
return FALSE;
}
wrdata2 = weak_ref_data_get_surely (object);
if (wrdata == wrdata2)
{
if (out_new_wrdata)
*out_new_wrdata = NULL;
return TRUE;
}
if (out_new_wrdata)
*out_new_wrdata = weak_ref_data_ref (wrdata2);
return FALSE;
}
/*****************************************************************************/
#if defined(G_ENABLE_DEBUG) && defined(G_THREAD_LOCAL)
/* Using this thread-local global is sufficient to guard the per-object
* locking, because while the current thread holds a lock on one object, it
* never calls out to another object (because doing so would would be prone to
* deadlock). */
static G_THREAD_LOCAL guint _object_bit_is_locked;
#endif
static void
object_bit_lock (GObject *object, guint lock_bit)
{
#if defined(G_ENABLE_DEBUG) && defined(G_THREAD_LOCAL)
/* all object_bit_lock() really use the same bit/mutex. The "lock_bit" argument
* only exists for asserting. object_bit_lock() is not re-entrant (also not with
* different "lock_bit" values). */
g_assert (lock_bit > 0);
g_assert (_object_bit_is_locked == 0);
_object_bit_is_locked = lock_bit;
#endif
g_bit_lock ((gint *) object_get_optional_flags_p (object), _OPTIONAL_BIT_LOCK);
}
static void
object_bit_unlock (GObject *object, guint lock_bit)
{
#if defined(G_ENABLE_DEBUG) && defined(G_THREAD_LOCAL)
/* All lock_bit map to the same mutex. We cannot use two different locks on
* the same integer. Assert against that. */
g_assert (lock_bit > 0);
g_assert (_object_bit_is_locked == lock_bit);
_object_bit_is_locked = 0;
#endif
/* Warning: after unlock, @object may be a dangling pointer (destroyed on
* another thread) and must not be touched anymore. */
g_bit_unlock ((gint *) object_get_optional_flags_p (object), _OPTIONAL_BIT_LOCK);
}
/* --- functions --- */
static void
g_object_notify_queue_free (gpointer data)
{
GObjectNotifyQueue *nqueue = data;
g_slist_free (nqueue->pspecs);
g_free_sized (nqueue, sizeof (GObjectNotifyQueue));
}
static GObjectNotifyQueue *
g_object_notify_queue_create_queue_frozen (GObject *object)
{
GObjectNotifyQueue *nqueue;
nqueue = g_new0 (GObjectNotifyQueue, 1);
*nqueue = (GObjectNotifyQueue){
.freeze_count = 1,
};
g_datalist_id_set_data_full (&object->qdata, quark_notify_queue,
nqueue, g_object_notify_queue_free);
return nqueue;
}
static GObjectNotifyQueue *
g_object_notify_queue_freeze (GObject *object)
{
GObjectNotifyQueue *nqueue;
object_bit_lock (object, OPTIONAL_BIT_LOCK_NOTIFY);
nqueue = g_datalist_id_get_data (&object->qdata, quark_notify_queue);
if (!nqueue)
{
nqueue = g_object_notify_queue_create_queue_frozen (object);
goto out;
}
if (nqueue->freeze_count >= 65535)
g_critical("Free queue for %s (%p) is larger than 65535,"
" called g_object_freeze_notify() too often."
" Forgot to call g_object_thaw_notify() or infinite loop",
G_OBJECT_TYPE_NAME (object), object);
else
nqueue->freeze_count++;
out:
object_bit_unlock (object, OPTIONAL_BIT_LOCK_NOTIFY);
return nqueue;
}
static void
g_object_notify_queue_thaw (GObject *object,
GObjectNotifyQueue *nqueue,
gboolean take_ref)
{
GParamSpec *pspecs_mem[16], **pspecs, **free_me = NULL;
GSList *slist;
guint n_pspecs = 0;
object_bit_lock (object, OPTIONAL_BIT_LOCK_NOTIFY);
if (!nqueue)
{
/* Caller didn't look up the queue yet. Do it now. */
nqueue = g_datalist_id_get_data (&object->qdata, quark_notify_queue);
}
/* Just make sure we never get into some nasty race condition */
if (G_UNLIKELY (!nqueue || nqueue->freeze_count == 0))
{
object_bit_unlock (object, OPTIONAL_BIT_LOCK_NOTIFY);
g_critical ("%s: property-changed notification for %s(%p) is not frozen",
G_STRFUNC, G_OBJECT_TYPE_NAME (object), object);
return;
}
nqueue->freeze_count--;
if (nqueue->freeze_count)
{
object_bit_unlock (object, OPTIONAL_BIT_LOCK_NOTIFY);
return;
}
pspecs = nqueue->n_pspecs > 16 ? free_me = g_new (GParamSpec*, nqueue->n_pspecs) : pspecs_mem;
for (slist = nqueue->pspecs; slist; slist = slist->next)
{
pspecs[n_pspecs++] = slist->data;
}
g_datalist_id_set_data (&object->qdata, quark_notify_queue, NULL);
object_bit_unlock (object, OPTIONAL_BIT_LOCK_NOTIFY);
if (n_pspecs)
{
if (take_ref)
g_object_ref (object);
G_OBJECT_GET_CLASS (object)->dispatch_properties_changed (object, n_pspecs, pspecs);
if (take_ref)
g_object_unref (object);
}
g_free (free_me);
}
static gboolean
g_object_notify_queue_add (GObject *object,
GObjectNotifyQueue *nqueue,
GParamSpec *pspec,
gboolean in_init)
{
object_bit_lock (object, OPTIONAL_BIT_LOCK_NOTIFY);
if (!nqueue)
{
/* We are called without an nqueue. Figure out whether a notification
* should be queued. */
nqueue = g_datalist_id_get_data (&object->qdata, quark_notify_queue);
if (!nqueue)
{
if (!in_init)
{
/* We don't have a notify queue and are not in_init. The event
* is not to be queued. The caller will dispatch directly. */
object_bit_unlock (object, OPTIONAL_BIT_LOCK_NOTIFY);
return FALSE;
}
/* We are "in_init", but did not freeze the queue in g_object_init
* yet. Instead, we gained a notify handler in instance init, so now
* we need to freeze just-in-time.
*
* Note that this freeze will be balanced at the end of object
* initialization.
*/
nqueue = g_object_notify_queue_create_queue_frozen (object);
}
}
g_assert (nqueue->n_pspecs < 65535);
if (g_slist_find (nqueue->pspecs, pspec) == NULL)
{
nqueue->pspecs = g_slist_prepend (nqueue->pspecs, pspec);
nqueue->n_pspecs++;
}
object_bit_unlock (object, OPTIONAL_BIT_LOCK_NOTIFY);
return TRUE;
}
#ifdef G_ENABLE_DEBUG
G_LOCK_DEFINE_STATIC (debug_objects);
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);
}
#ifdef G_HAS_CONSTRUCTORS
#ifdef G_DEFINE_DESTRUCTOR_NEEDS_PRAGMA
#pragma G_DEFINE_DESTRUCTOR_PRAGMA_ARGS(debug_objects_atexit)
#endif
G_DEFINE_DESTRUCTOR(debug_objects_atexit)
#endif /* G_HAS_CONSTRUCTORS */
static void
debug_objects_atexit (void)
{
GOBJECT_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)
{
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,
};
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_GNUC_UNUSED /* when compiling with G_DISABLE_ASSERT */;
g_return_if_fail (initialized == FALSE);
initialized = TRUE;
/* G_TYPE_OBJECT
*/
info.value_table = &value_table;
type = g_type_register_fundamental (G_TYPE_OBJECT, g_intern_static_string ("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);
#if G_ENABLE_DEBUG
/* We cannot use GOBJECT_IF_DEBUG here because of the G_HAS_CONSTRUCTORS
* conditional in between, as the C spec leaves conditionals inside macro
* expansions as undefined behavior. Only GCC and Clang are known to work
* but compilation breaks on MSVC.
*
* See: https://bugzilla.gnome.org/show_bug.cgi?id=769504
*/
if (_g_type_debug_flags & G_TYPE_DEBUG_OBJECTS) \
{
debug_objects_ht = g_hash_table_new (g_direct_hash, NULL);
# ifndef G_HAS_CONSTRUCTORS
g_atexit (debug_objects_atexit);
# endif /* G_HAS_CONSTRUCTORS */
}
#endif /* G_ENABLE_DEBUG */
#if HAVE_PRIVATE
GObject_private_offset =
g_type_add_instance_private (G_TYPE_OBJECT, sizeof (GObjectPrivate));
#endif
}
/* Initialize the global GParamSpecPool; this function needs to be
* called whenever we access the GParamSpecPool and we cannot guarantee
* that g_object_do_class_init() has been called: for instance, by the
* interface property API.
*
* To avoid yet another global lock, we use atomic pointer checks: the
* first caller of this function will win the race. Any other access to
* the GParamSpecPool is done under its own mutex.
*/
static inline void
g_object_init_pspec_pool (void)
{
if (G_UNLIKELY (g_atomic_pointer_get (&pspec_pool) == NULL))
{
GParamSpecPool *pool = g_param_spec_pool_new (TRUE);
if (!g_atomic_pointer_compare_and_exchange (&pspec_pool, NULL, pool))
g_param_spec_pool_free (pool);
}
}
static void
g_object_base_class_init (GObjectClass *class)
{
GObjectClass *pclass = g_type_class_peek_parent (class);
/* Don't inherit HAS_DERIVED_CLASS flag from parent class */
class->flags &= ~CLASS_HAS_DERIVED_CLASS_FLAG;
if (pclass)
pclass->flags |= CLASS_HAS_DERIVED_CLASS_FLAG;
/* reset instance specific fields and methods that don't get inherited */
class->construct_properties = pclass ? g_slist_copy (pclass->construct_properties) : NULL;
class->n_construct_properties = g_slist_length (class->construct_properties);
class->get_property = NULL;
class->set_property = NULL;
class->pspecs = NULL;
class->n_pspecs = 0;
}
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;
class->n_construct_properties = 0;
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_do_class_init (GObjectClass *class)
{
quark_closure_array = g_quark_from_static_string ("GObject-closure-array");
quark_weak_notifies = g_quark_from_static_string ("GObject-weak-notifies");
quark_weak_locations = g_quark_from_static_string ("GObject-weak-locations");
quark_toggle_refs = g_quark_from_static_string ("GObject-toggle-references");
quark_notify_queue = g_quark_from_static_string ("GObject-notify-queue");
g_object_init_pspec_pool ();
class->constructor = g_object_constructor;
class->constructed = g_object_constructed;
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::notify:
* @gobject: the object which received the signal.
* @pspec: the #GParamSpec of the property which changed.
*
* The notify signal is emitted on an object when one of its properties has
* its value set through g_object_set_property(), g_object_set(), et al.
*
* Note that getting this signal doesn’t itself guarantee that the value of
* the property has actually changed. When it is emitted is determined by the
* derived GObject class. If the implementor did not create the property with
* %G_PARAM_EXPLICIT_NOTIFY, then any call to g_object_set_property() results
* in ::notify being emitted, even if the new value is the same as the old.
* If they did pass %G_PARAM_EXPLICIT_NOTIFY, then this signal is emitted only
* when they explicitly call g_object_notify() or g_object_notify_by_pspec(),
* and common practice is to do that only when the value has actually changed.
*
* This signal is typically used to obtain change notification for a
* single property, by specifying the property name as a detail in the
* g_signal_connect() call, like this:
*
* |[<!-- language="C" -->
* g_signal_connect (text_view->buffer, "notify::paste-target-list",
* G_CALLBACK (gtk_text_view_target_list_notify),
* text_view)
* ]|
*
* It is important to note that you must use
* [canonical parameter names][class@GObject.ParamSpec#parameter-names] as
* detail strings for the notify signal.
*/
gobject_signals[NOTIFY] =
g_signal_new (g_intern_static_string ("notify"),
G_TYPE_FROM_CLASS (class),
G_SIGNAL_RUN_FIRST | G_SIGNAL_NO_RECURSE | G_SIGNAL_DETAILED | G_SIGNAL_NO_HOOKS | G_SIGNAL_ACTION,
G_STRUCT_OFFSET (GObjectClass, notify),
NULL, NULL,
NULL,
G_TYPE_NONE,
1, G_TYPE_PARAM);
/* Install a check function that we'll use to verify that classes that
* implement an interface implement all properties for that interface
*/
g_type_add_interface_check (NULL, object_interface_check_properties);
#if HAVE_PRIVATE
g_type_class_adjust_private_offset (class, &GObject_private_offset);
#endif
}
/* Sinks @pspec if it’s a floating ref. */
static inline gboolean
install_property_internal (GType g_type,
guint property_id,
GParamSpec *pspec)
{
g_param_spec_ref_sink (pspec);
g_object_init_pspec_pool ();
if (g_param_spec_pool_lookup (pspec_pool, pspec->name, g_type, FALSE))
{
g_critical ("When installing property: type '%s' already has a property named '%s'",
g_type_name (g_type),
pspec->name);
g_param_spec_unref (pspec);
return FALSE;
}
PARAM_SPEC_SET_PARAM_ID (pspec, property_id);
g_param_spec_pool_insert (pspec_pool, g_steal_pointer (&pspec), g_type);
return TRUE;
}
static gboolean
validate_pspec_to_install (GParamSpec *pspec)
{
g_return_val_if_fail (G_IS_PARAM_SPEC (pspec), FALSE);
g_return_val_if_fail (PARAM_SPEC_PARAM_ID (pspec) == 0, FALSE); /* paranoid */
g_return_val_if_fail (pspec->flags & (G_PARAM_READABLE | G_PARAM_WRITABLE), FALSE);
if (pspec->flags & G_PARAM_CONSTRUCT)
g_return_val_if_fail ((pspec->flags & G_PARAM_CONSTRUCT_ONLY) == 0, FALSE);
if (pspec->flags & (G_PARAM_CONSTRUCT | G_PARAM_CONSTRUCT_ONLY))
g_return_val_if_fail (pspec->flags & G_PARAM_WRITABLE, FALSE);
return TRUE;
}
/* Sinks @pspec if it’s a floating ref. */
static gboolean
validate_and_install_class_property (GObjectClass *class,
GType oclass_type,
GType parent_type,
guint property_id,
GParamSpec *pspec)
{
if (!validate_pspec_to_install (pspec))
{
g_param_spec_ref_sink (pspec);
g_param_spec_unref (pspec);
return FALSE;
}
if (pspec->flags & G_PARAM_WRITABLE)
g_return_val_if_fail (class->set_property != NULL, FALSE);
if (pspec->flags & G_PARAM_READABLE)
g_return_val_if_fail (class->get_property != NULL, FALSE);
class->flags |= CLASS_HAS_PROPS_FLAG;
if (install_property_internal (oclass_type, property_id, pspec))
{
if (pspec->flags & (G_PARAM_CONSTRUCT | G_PARAM_CONSTRUCT_ONLY))
{
class->construct_properties = g_slist_append (class->construct_properties, pspec);
class->n_construct_properties += 1;
}
/* for property overrides of construct properties, we have to get rid
* of the overridden inherited construct property
*/
pspec = g_param_spec_pool_lookup (pspec_pool, pspec->name, parent_type, TRUE);
if (pspec && pspec->flags & (G_PARAM_CONSTRUCT | G_PARAM_CONSTRUCT_ONLY))
{
class->construct_properties = g_slist_remove (class->construct_properties, pspec);
class->n_construct_properties -= 1;
}
return TRUE;
}
else
return FALSE;
}
/**
* g_object_class_install_property:
* @oclass: a #GObjectClass
* @property_id: the id for the new property
* @pspec: the #GParamSpec for the new property
*
* Installs a new property.
*
* All properties should be installed during the class initializer. It
* is possible to install properties after that, but doing so is not
* recommend, and specifically, is not guaranteed to be thread-safe vs.
* use of properties on the same type on other threads.
*
* Note that it is possible to redefine a property in a derived class,
* by installing a property with the same name. This can be useful at times,
* e.g. to change the range of allowed values or the default value.
*/
void
g_object_class_install_property (GObjectClass *class,
guint property_id,
GParamSpec *pspec)
{
GType oclass_type, parent_type;
g_return_if_fail (G_IS_OBJECT_CLASS (class));
g_return_if_fail (property_id > 0);
oclass_type = G_OBJECT_CLASS_TYPE (class);
parent_type = g_type_parent (oclass_type);
if (CLASS_HAS_DERIVED_CLASS (class))
g_error ("Attempt to add property %s::%s to class after it was derived", G_OBJECT_CLASS_NAME (class), pspec->name);
(void) validate_and_install_class_property (class,
oclass_type,
parent_type,
property_id,
pspec);
}
typedef struct {
const char *name;
GParamSpec *pspec;
} PspecEntry;
static int
compare_pspec_entry (const void *a,
const void *b)
{
const PspecEntry *ae = a;
const PspecEntry *be = b;
return ae->name < be->name ? -1 : (ae->name > be->name ? 1 : 0);
}
/* This uses pointer comparisons with @property_name, so
* will only work with string literals. */
static inline GParamSpec *
find_pspec (GObjectClass *class,
const char *property_name)
{
const PspecEntry *pspecs = (const PspecEntry *)class->pspecs;
gsize n_pspecs = class->n_pspecs;
g_assert (n_pspecs <= G_MAXSSIZE);
/* The limit for choosing between linear and binary search is
* fairly arbitrary.
*
* Both searches use pointer comparisons against @property_name.
* If this function is called with a non-static @property_name,
* it will fall through to the g_param_spec_pool_lookup() case.
* That’s OK; this is an opportunistic optimisation which relies
* on the fact that *most* (but not all) property lookups use
* static property names.
*/
if (n_pspecs < 10)
{
for (gsize i = 0; i < n_pspecs; i++)
{
if (pspecs[i].name == property_name)
return pspecs[i].pspec;
}
}
else
{
gssize lower = 0;
gssize upper = (int)class->n_pspecs - 1;
gssize mid;
while (lower <= upper)
{
mid = (lower + upper) / 2;
if (property_name < pspecs[mid].name)
upper = mid - 1;
else if (property_name > pspecs[mid].name)
lower = mid + 1;
else
return pspecs[mid].pspec;
}
}
return g_param_spec_pool_lookup (pspec_pool,
property_name,
((GTypeClass *)class)->g_type,
TRUE);
}
/**
* g_object_class_install_properties:
* @oclass: a #GObjectClass
* @n_pspecs: the length of the #GParamSpecs array
* @pspecs: (array length=n_pspecs): the #GParamSpecs array
* defining the new properties
*
* Installs new properties from an array of #GParamSpecs.
*
* All properties should be installed during the class initializer. It
* is possible to install properties after that, but doing so is not
* recommend, and specifically, is not guaranteed to be thread-safe vs.
* use of properties on the same type on other threads.
*
* The property id of each property is the index of each #GParamSpec in
* the @pspecs array.
*
* The property id of 0 is treated specially by #GObject and it should not
* be used to store a #GParamSpec.
*
* This function should be used if you plan to use a static array of
* #GParamSpecs and g_object_notify_by_pspec(). For instance, this
* class initialization:
*
* |[<!-- language="C" -->
* typedef enum {
* PROP_FOO = 1,
* PROP_BAR,
* N_PROPERTIES
* } MyObjectProperty;
*
* static GParamSpec *obj_properties[N_PROPERTIES] = { NULL, };
*
* static void
* my_object_class_init (MyObjectClass *klass)
* {
* GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
*
* obj_properties[PROP_FOO] =
* g_param_spec_int ("foo", NULL, NULL,
* -1, G_MAXINT,
* 0,
* G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS);
*
* obj_properties[PROP_BAR] =
* g_param_spec_string ("bar", NULL, NULL,
* NULL,
* G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS);
*
* gobject_class->set_property = my_object_set_property;
* gobject_class->get_property = my_object_get_property;
* g_object_class_install_properties (gobject_class,
* G_N_ELEMENTS (obj_properties),
* obj_properties);
* }
* ]|
*
* allows calling g_object_notify_by_pspec() to notify of property changes:
*
* |[<!-- language="C" -->
* void
* my_object_set_foo (MyObject *self, gint foo)
* {
* if (self->foo != foo)
* {
* self->foo = foo;
* g_object_notify_by_pspec (G_OBJECT (self), obj_properties[PROP_FOO]);
* }
* }
* ]|
*
* Since: 2.26
*/
void
g_object_class_install_properties (GObjectClass *oclass,
guint n_pspecs,
GParamSpec **pspecs)
{
GType oclass_type, parent_type;
guint i;
g_return_if_fail (G_IS_OBJECT_CLASS (oclass));
g_return_if_fail (n_pspecs > 1);
g_return_if_fail (pspecs[0] == NULL);
if (CLASS_HAS_DERIVED_CLASS (oclass))
g_error ("Attempt to add properties to %s after it was derived",
G_OBJECT_CLASS_NAME (oclass));
oclass_type = G_OBJECT_CLASS_TYPE (oclass);
parent_type = g_type_parent (oclass_type);
/* we skip the first element of the array as it would have a 0 prop_id */
for (i = 1; i < n_pspecs; i++)
{
GParamSpec *pspec = pspecs[i];
if (!validate_and_install_class_property (oclass,
oclass_type,
parent_type,
i,
pspec))
{
break;
}
}
/* Save a copy of the pspec array inside the class struct. This
* makes it faster to look up pspecs for the class in future when
* acting on those properties.
*
* If a pspec is not in this cache array, calling code will fall
* back to using g_param_spec_pool_lookup(), so a pspec not being
* in this array is a (potential) performance problem but not a
* correctness problem. */
if (oclass->pspecs == NULL)
{
PspecEntry *entries;
entries = g_new (PspecEntry, n_pspecs - 1);
for (i = 1; i < n_pspecs; i++)
{
entries[i - 1].name = pspecs[i]->name;
entries[i - 1].pspec = pspecs[i];
}
qsort (entries, n_pspecs - 1, sizeof (PspecEntry), compare_pspec_entry);
oclass->pspecs = entries;
oclass->n_pspecs = n_pspecs - 1;
}
}
/**
* g_object_interface_install_property:
* @g_iface: (type GObject.TypeInterface): any interface vtable for the
* interface, or the default
* vtable for the interface.
* @pspec: the #GParamSpec for the new property
*
* Add a property to an interface; this is only useful for interfaces
* that are added to GObject-derived types. Adding a property to an
* interface forces all objects classes with that interface to have a
* compatible property. The compatible property could be a newly
* created #GParamSpec, but normally
* g_object_class_override_property() will be used so that the object
* class only needs to provide an implementation and inherits the
* property description, default value, bounds, and so forth from the
* interface property.
*
* This function is meant to be called from the interface's default
* vtable initialization function (the @class_init member of
* #GTypeInfo.) It must not be called after after @class_init has
* been called for any object types implementing this interface.
*
* If @pspec is a floating reference, it will be consumed.
*
* Since: 2.4
*/
void
g_object_interface_install_property (gpointer g_iface,
GParamSpec *pspec)
{
GTypeInterface *iface_class = g_iface;
g_return_if_fail (G_TYPE_IS_INTERFACE (iface_class->g_type));
g_return_if_fail (!G_IS_PARAM_SPEC_OVERRIDE (pspec)); /* paranoid */
if (!validate_pspec_to_install (pspec))
{
g_param_spec_ref_sink (pspec);
g_param_spec_unref (pspec);
return;
}
(void) install_property_internal (iface_class->g_type, 0, pspec);
}
/* Inlined version of g_param_spec_get_redirect_target(), for speed */
static inline void
param_spec_follow_override (GParamSpec **pspec)
{
if (((GTypeInstance *) (*pspec))->g_class->g_type == G_TYPE_PARAM_OVERRIDE)
*pspec = ((GParamSpecOverride *) (*pspec))->overridden;
}
/**
* g_object_class_find_property:
* @oclass: a #GObjectClass
* @property_name: the name of the property to look up
*
* Looks up the #GParamSpec for a property of a class.
*
* Returns: (transfer none): the #GParamSpec for the property, or
* %NULL if the class doesn't have a property of that name
*/
GParamSpec*
g_object_class_find_property (GObjectClass *class,
const gchar *property_name)
{
GParamSpec *pspec;
g_return_val_if_fail (G_IS_OBJECT_CLASS (class), NULL);
g_return_val_if_fail (property_name != NULL, NULL);
pspec = find_pspec (class, property_name);
if (pspec)
param_spec_follow_override (&pspec);
return pspec;
}
/**
* g_object_interface_find_property:
* @g_iface: (type GObject.TypeInterface): any interface vtable for the
* interface, or the default vtable for the interface
* @property_name: name of a property to look up.
*
* Find the #GParamSpec with the given name for an
* interface. Generally, the interface vtable passed in as @g_iface
* will be the default vtable from g_type_default_interface_ref(), or,
* if you know the interface has already been loaded,
* g_type_default_interface_peek().
*
* Since: 2.4
*
* Returns: (transfer none): the #GParamSpec for the property of the
* interface with the name @property_name, or %NULL if no
* such property exists.
*/
GParamSpec*
g_object_interface_find_property (gpointer g_iface,
const gchar *property_name)
{
GTypeInterface *iface_class = g_iface;
g_return_val_if_fail (G_TYPE_IS_INTERFACE (iface_class->g_type), NULL);
g_return_val_if_fail (property_name != NULL, NULL);
g_object_init_pspec_pool ();
return g_param_spec_pool_lookup (pspec_pool,
property_name,
iface_class->g_type,
FALSE);
}
/**
* g_object_class_override_property:
* @oclass: a #GObjectClass
* @property_id: the new property ID
* @name: the name of a property registered in a parent class or
* in an interface of this class.
*
* Registers @property_id as referring to a property with the name
* @name in a parent class or in an interface implemented by @oclass.
* This allows this class to "override" a property implementation in
* a parent class or to provide the implementation of a property from
* an interface.
*
* Internally, overriding is implemented by creating a property of type
* #GParamSpecOverride; generally operations that query the properties of
* the object class, such as g_object_class_find_property() or
* g_object_class_list_properties() will return the overridden
* property. However, in one case, the @construct_properties argument of
* the @constructor virtual function, the #GParamSpecOverride is passed
* instead, so that the @param_id field of the #GParamSpec will be
* correct. For virtually all uses, this makes no difference. If you
* need to get the overridden property, you can call
* g_param_spec_get_redirect_target().
*
* Since: 2.4
*/
void
g_object_class_override_property (GObjectClass *oclass,
guint property_id,
const gchar *name)
{
GParamSpec *overridden = NULL;
GParamSpec *new;
GType parent_type;
g_return_if_fail (G_IS_OBJECT_CLASS (oclass));
g_return_if_fail (property_id > 0);
g_return_if_fail (name != NULL);
/* Find the overridden property; first check parent types
*/
parent_type = g_type_parent (G_OBJECT_CLASS_TYPE (oclass));
if (parent_type != G_TYPE_NONE)
overridden = g_param_spec_pool_lookup (pspec_pool,
name,
parent_type,
TRUE);
if (!overridden)
{
GType *ifaces;
guint n_ifaces;
/* Now check interfaces
*/
ifaces = g_type_interfaces (G_OBJECT_CLASS_TYPE (oclass), &n_ifaces);
while (n_ifaces-- && !overridden)
{
overridden = g_param_spec_pool_lookup (pspec_pool,
name,
ifaces[n_ifaces],
FALSE);
}
g_free (ifaces);
}
if (!overridden)
{
g_critical ("%s: Can't find property to override for '%s::%s'",
G_STRFUNC, G_OBJECT_CLASS_NAME (oclass), name);
return;
}
new = g_param_spec_override (name, overridden);
g_object_class_install_property (oclass, property_id, new);
}
/**
* g_object_class_list_properties:
* @oclass: a #GObjectClass
* @n_properties: (out): return location for the length of the returned array
*
* Get an array of #GParamSpec* for all properties of a class.
*
* Returns: (array length=n_properties) (transfer container): an array of
* #GParamSpec* which should be freed after use
*/
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;
}
/**
* g_object_interface_list_properties:
* @g_iface: (type GObject.TypeInterface): any interface vtable for the
* interface, or the default vtable for the interface
* @n_properties_p: (out): location to store number of properties returned.
*
* Lists the properties of an interface.Generally, the interface
* vtable passed in as @g_iface will be the default vtable from
* g_type_default_interface_ref(), or, if you know the interface has
* already been loaded, g_type_default_interface_peek().
*
* Since: 2.4
*
* Returns: (array length=n_properties_p) (transfer container): a
* pointer to an array of pointers to #GParamSpec
* structures. The paramspecs are owned by GLib, but the
* array should be freed with g_free() when you are done with
* it.
*/
GParamSpec**
g_object_interface_list_properties (gpointer g_iface,
guint *n_properties_p)
{
GTypeInterface *iface_class = g_iface;
GParamSpec **pspecs;
guint n;
g_return_val_if_fail (G_TYPE_IS_INTERFACE (iface_class->g_type), NULL);
g_object_init_pspec_pool ();
pspecs = g_param_spec_pool_list (pspec_pool,
iface_class->g_type,
&n);
if (n_properties_p)
*n_properties_p = n;
return pspecs;
}
static inline guint
object_get_optional_flags (GObject *object)
{
return g_atomic_int_get (object_get_optional_flags_p (object));
}
static inline void
object_set_optional_flags (GObject *object,
guint flags)
{
g_atomic_int_or (object_get_optional_flags_p (object), flags);
}
static inline void
object_unset_optional_flags (GObject *object,
guint flags)
{
g_atomic_int_and (object_get_optional_flags_p (object), ~flags);
}
gboolean
_g_object_has_signal_handler (GObject *object)
{
return (object_get_optional_flags (object) & OPTIONAL_FLAG_HAS_SIGNAL_HANDLER) != 0;
}
static inline gboolean
_g_object_has_notify_handler (GObject *object)
{
return CLASS_NEEDS_NOTIFY (G_OBJECT_GET_CLASS (object)) ||
(object_get_optional_flags (object) & OPTIONAL_FLAG_HAS_NOTIFY_HANDLER) != 0;
}
void
_g_object_set_has_signal_handler (GObject *object,
guint signal_id)
{
guint flags = OPTIONAL_FLAG_HAS_SIGNAL_HANDLER;
if (signal_id == gobject_signals[NOTIFY])
flags |= OPTIONAL_FLAG_HAS_NOTIFY_HANDLER;
object_set_optional_flags (object, flags);
}
static inline gboolean
object_in_construction (GObject *object)
{
return (object_get_optional_flags (object) & OPTIONAL_FLAG_IN_CONSTRUCTION) != 0;
}
static inline void
set_object_in_construction (GObject *object)
{
object_set_optional_flags (object, OPTIONAL_FLAG_IN_CONSTRUCTION);
}
static inline void
unset_object_in_construction (GObject *object)
{
object_unset_optional_flags (object, OPTIONAL_FLAG_IN_CONSTRUCTION);
}
static void
g_object_init (GObject *object,
GObjectClass *class)
{
object->ref_count = 1;
object->qdata = NULL;
if (CLASS_HAS_PROPS (class) && CLASS_NEEDS_NOTIFY (class))
{
/* freeze object's notification queue, g_object_new_internal() preserves pairedness */
g_object_notify_queue_freeze (object);
}
/* mark object in-construction for notify_queue_thaw() and to allow construct-only properties */
set_object_in_construction (object);
GOBJECT_IF_DEBUG (OBJECTS,
{
G_LOCK (debug_objects);
debug_objects_count++;
g_hash_table_add (debug_objects_ht, object);
G_UNLOCK (debug_objects);
});
}
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)
{
g_signal_handlers_destroy (object);
/* GWeakNotify and GClosure can call into user code */
g_datalist_id_set_data (&object->qdata, quark_weak_notifies, NULL);
g_datalist_id_set_data (&object->qdata, quark_closure_array, NULL);
}
#ifdef G_ENABLE_DEBUG
static gboolean
floating_check (GObject *object)
{
static const char *g_enable_diagnostic = NULL;
if (G_UNLIKELY (g_enable_diagnostic == NULL))
{
g_enable_diagnostic = g_getenv ("G_ENABLE_DIAGNOSTIC");
if (g_enable_diagnostic == NULL)
g_enable_diagnostic = "0";
}
if (g_enable_diagnostic[0] == '1')
return g_object_is_floating (object);
return FALSE;
}
#endif
static void
g_object_finalize (GObject *object)
{
#ifdef G_ENABLE_DEBUG
if (object_in_construction (object))
{
g_critical ("object %s %p finalized while still in-construction",
G_OBJECT_TYPE_NAME (object), object);
}
if (floating_check (object))
{
g_critical ("A floating object %s %p was finalized. This means that someone\n"
"called g_object_unref() on an object that had only a floating\n"
"reference; the initial floating reference is not owned by anyone\n"
"and must be removed with g_object_ref_sink().",
G_OBJECT_TYPE_NAME (object), object);
}
#endif
g_datalist_clear (&object->qdata);
GOBJECT_IF_DEBUG (OBJECTS,
{
G_LOCK (debug_objects);
g_assert (g_hash_table_contains (debug_objects_ht, object));
g_hash_table_remove (debug_objects_ht, object);
debug_objects_count--;
G_UNLOCK (debug_objects);
});
}
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_param_spec_get_name_quark (pspecs[i]), pspecs[i]);
}
/**
* g_object_run_dispose:
* @object: a #GObject
*
* Releases all references to other objects. This can be used to break
* reference cycles.
*
* This function should only be called from object system implementations.
*/
void
g_object_run_dispose (GObject *object)
{
WeakRefData *wrdata;
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (g_atomic_int_get (&object->ref_count) > 0);
g_object_ref (object);
TRACE (GOBJECT_OBJECT_DISPOSE(object,G_TYPE_FROM_INSTANCE(object), 0));
G_OBJECT_GET_CLASS (object)->dispose (object);
TRACE (GOBJECT_OBJECT_DISPOSE_END(object,G_TYPE_FROM_INSTANCE(object), 0));
if ((object_get_optional_flags (object) & OPTIONAL_FLAG_EVER_HAD_WEAK_REF))
{
wrdata = weak_ref_data_get_surely (object);
weak_ref_data_lock (wrdata);
weak_ref_data_clear_list (wrdata, object);
weak_ref_data_unlock (wrdata);
}
g_object_unref (object);
}
/**
* g_object_freeze_notify:
* @object: a #GObject
*
* Increases the freeze count on @object. If the freeze count is
* non-zero, the emission of "notify" signals on @object is
* stopped. The signals are queued until the freeze count is decreased
* to zero. Duplicate notifications are squashed so that at most one
* #GObject::notify signal is emitted for each property modified while the
* object is frozen.
*
* This is necessary for accessors that modify multiple properties to prevent
* premature notification while the object is still being modified.
*/
void
g_object_freeze_notify (GObject *object)
{
g_return_if_fail (G_IS_OBJECT (object));
#ifndef G_DISABLE_CHECKS
if (G_UNLIKELY (g_atomic_int_get (&object->ref_count) <= 0))
{
g_critical ("Attempting to freeze the notification queue for object %s[%p]; "
"Property notification does not work during instance finalization.",
G_OBJECT_TYPE_NAME (object),
object);
return;
}
#endif
g_object_notify_queue_freeze (object);
}
static inline void
g_object_notify_by_spec_internal (GObject *object,
GParamSpec *pspec)
{
guint object_flags;
gboolean needs_notify;
gboolean in_init;
if (G_UNLIKELY (~pspec->flags & G_PARAM_READABLE))
return;
param_spec_follow_override (&pspec);
/* get all flags we need with a single atomic read */
object_flags = object_get_optional_flags (object);
needs_notify = ((object_flags & OPTIONAL_FLAG_HAS_NOTIFY_HANDLER) != 0) ||
CLASS_NEEDS_NOTIFY (G_OBJECT_GET_CLASS (object));
in_init = (object_flags & OPTIONAL_FLAG_IN_CONSTRUCTION) != 0;
if (pspec != NULL && needs_notify)
{
if (!g_object_notify_queue_add (object, NULL, pspec, in_init))
{
/*
* Coverity doesn’t understand the paired ref/unref here and seems to
* ignore the ref, thus reports every call to g_object_notify() as
* causing a double-free. That’s incorrect, but I can’t get a model
* file to work for avoiding the false positives, so instead comment
* out the ref/unref when doing static analysis.
*/
#ifndef __COVERITY__
g_object_ref (object);
#endif
/* not frozen, so just dispatch the notification directly */
G_OBJECT_GET_CLASS (object)
->dispatch_properties_changed (object, 1, &pspec);
#ifndef __COVERITY__
g_object_unref (object);
#endif
}
}
}
/**
* g_object_notify:
* @object: a #GObject
* @property_name: the name of a property installed on the class of @object.
*
* Emits a "notify" signal for the property @property_name on @object.
*
* When possible, eg. when signaling a property change from within the class
* that registered the property, you should use g_object_notify_by_pspec()
* instead.
*
* Note that emission of the notify signal may be blocked with
* g_object_freeze_notify(). In this case, the signal emissions are queued
* and will be emitted (in reverse order) when g_object_thaw_notify() is
* called.
*/
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);
/* We don't need to get the redirect target
* (by, e.g. calling g_object_class_find_property())
* because g_object_notify_queue_add() does that
*/
pspec = g_param_spec_pool_lookup (pspec_pool,
property_name,
G_OBJECT_TYPE (object),
TRUE);
if (!pspec)
g_critical ("%s: object class '%s' has no property named '%s'",
G_STRFUNC,
G_OBJECT_TYPE_NAME (object),
property_name);
else
g_object_notify_by_spec_internal (object, pspec);
}
/**
* g_object_notify_by_pspec:
* @object: a #GObject
* @pspec: the #GParamSpec of a property installed on the class of @object.
*
* Emits a "notify" signal for the property specified by @pspec on @object.
*
* This function omits the property name lookup, hence it is faster than
* g_object_notify().
*
* One way to avoid using g_object_notify() from within the
* class that registered the properties, and using g_object_notify_by_pspec()
* instead, is to store the GParamSpec used with
* g_object_class_install_property() inside a static array, e.g.:
*
*|[<!-- language="C" -->
* typedef enum
* {
* PROP_FOO = 1,
* PROP_LAST
* } MyObjectProperty;
*
* static GParamSpec *properties[PROP_LAST];
*
* static void
* my_object_class_init (MyObjectClass *klass)
* {
* properties[PROP_FOO] = g_param_spec_int ("foo", NULL, NULL,
* 0, 100,
* 50,
* G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS);
* g_object_class_install_property (gobject_class,
* PROP_FOO,
* properties[PROP_FOO]);
* }
* ]|
*
* and then notify a change on the "foo" property with:
*
* |[<!-- language="C" -->
* g_object_notify_by_pspec (self, properties[PROP_FOO]);
* ]|
*
* Since: 2.26
*/
void
g_object_notify_by_pspec (GObject *object,
GParamSpec *pspec)
{
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (G_IS_PARAM_SPEC (pspec));
g_object_notify_by_spec_internal (object, pspec);
}
/**
* g_object_thaw_notify:
* @object: a #GObject
*
* Reverts the effect of a previous call to
* g_object_freeze_notify(). The freeze count is decreased on @object
* and when it reaches zero, queued "notify" signals are emitted.
*
* Duplicate notifications for each property are squashed so that at most one
* #GObject::notify signal is emitted for each property, in the reverse order
* in which they have been queued.
*
* It is an error to call this function when the freeze count is zero.
*/
void
g_object_thaw_notify (GObject *object)
{
g_return_if_fail (G_IS_OBJECT (object));
#ifndef G_DISABLE_CHECKS
if (G_UNLIKELY (g_atomic_int_get (&object->ref_count) <= 0))
{
g_critical ("Attempting to thaw the notification queue for object %s[%p]; "
"Property notification does not work during instance finalization.",
G_OBJECT_TYPE_NAME (object),
object);
return;
}
#endif
g_object_notify_queue_thaw (object, NULL, TRUE);
}
static void
maybe_issue_property_deprecation_warning (const GParamSpec *pspec)
{
static GHashTable *already_warned_table;
static const gchar *enable_diagnostic;
static GMutex already_warned_lock;
gboolean already;
if (g_once_init_enter_pointer (&enable_diagnostic))
{
const gchar *value = g_getenv ("G_ENABLE_DIAGNOSTIC");
if (!value)
value = "0";
g_once_init_leave_pointer (&enable_diagnostic, value);
}
if (enable_diagnostic[0] == '0')
return;
/* We hash only on property names: this means that we could end up in
* a situation where we fail to emit a warning about a pair of
* same-named deprecated properties used on two separate types.
* That's pretty unlikely to occur, and even if it does, you'll still
* have seen the warning for the first one...
*
* Doing it this way lets us hash directly on the (interned) property
* name pointers.
*/
g_mutex_lock (&already_warned_lock);
if (already_warned_table == NULL)
already_warned_table = g_hash_table_new (NULL, NULL);
already = g_hash_table_contains (already_warned_table, (gpointer) pspec->name);
if (!already)
g_hash_table_add (already_warned_table, (gpointer) pspec->name);
g_mutex_unlock (&already_warned_lock);
if (!already)
g_warning ("The property %s:%s is deprecated and shouldn't be used "
"anymore. It will be removed in a future version.",
g_type_name (pspec->owner_type), pspec->name);
}
static inline void
consider_issuing_property_deprecation_warning (const GParamSpec *pspec)
{
if (G_UNLIKELY (pspec->flags & G_PARAM_DEPRECATED))
maybe_issue_property_deprecation_warning (pspec);
}
static inline void
object_get_property (GObject *object,
GParamSpec *pspec,
GValue *value)
{
GTypeInstance *inst = (GTypeInstance *) object;
GObjectClass *class;
guint param_id = PARAM_SPEC_PARAM_ID (pspec);
if (G_LIKELY (inst->g_class->g_type == pspec->owner_type))
class = (GObjectClass *) inst->g_class;
else
class = g_type_class_peek (pspec->owner_type);
g_assert (class != NULL);
param_spec_follow_override (&pspec);
consider_issuing_property_deprecation_warning (pspec);
class->get_property (object, param_id, value, pspec);
}
static inline void
object_set_property (GObject *object,
GParamSpec *pspec,
const GValue *value,
GObjectNotifyQueue *nqueue,
gboolean user_specified)
{
GTypeInstance *inst = (GTypeInstance *) object;
GObjectClass *class;
GParamSpecClass *pclass;
guint param_id = PARAM_SPEC_PARAM_ID (pspec);
if (G_LIKELY (inst->g_class->g_type == pspec->owner_type))
class = (GObjectClass *) inst->g_class;
else
class = g_type_class_peek (pspec->owner_type);
g_assert (class != NULL);
param_spec_follow_override (&pspec);
if (user_specified)
consider_issuing_property_deprecation_warning (pspec);
pclass = G_PARAM_SPEC_GET_CLASS (pspec);
if (g_value_type_compatible (G_VALUE_TYPE (value), pspec->value_type) &&
(pclass->value_validate == NULL ||
(pclass->value_is_valid != NULL && pclass->value_is_valid (pspec, value))))
{
class->set_property (object, param_id, value, pspec);
}
else
{
/* provide a copy to work from, convert (if necessary) and validate */
GValue tmp_value = G_VALUE_INIT;
g_value_init (&tmp_value, pspec->value_type);
if (!g_value_transform (value, &tmp_value))
g_critical ("unable to set property '%s' of type '%s' from value of type '%s'",
pspec->name,
g_type_name (pspec->value_type),
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_critical ("value \"%s\" of type '%s' is invalid or out of range for property '%s' of type '%s'",
contents,
G_VALUE_TYPE_NAME (value),
pspec->name,
g_type_name (pspec->value_type));
g_free (contents);
}
else
{
class->set_property (object, param_id, &tmp_value, pspec);
}
g_value_unset (&tmp_value);
}
if ((pspec->flags & (G_PARAM_EXPLICIT_NOTIFY | G_PARAM_READABLE)) == G_PARAM_READABLE &&
nqueue != NULL)
g_object_notify_queue_add (object, nqueue, pspec, FALSE);
}
static void
object_interface_check_properties (gpointer check_data,
gpointer g_iface)
{
GTypeInterface *iface_class = g_iface;
GObjectClass *class;
GType iface_type = iface_class->g_type;
GParamSpec **pspecs;
guint n;
class = g_type_class_ref (iface_class->g_instance_type);
if (class == NULL)
return;
if (!G_IS_OBJECT_CLASS (class))
goto out;
pspecs = g_param_spec_pool_list (pspec_pool, iface_type, &n);
while (n--)
{
GParamSpec *class_pspec = g_param_spec_pool_lookup (pspec_pool,
pspecs[n]->name,
G_OBJECT_CLASS_TYPE (class),
TRUE);
if (!class_pspec)
{
g_critical ("Object class %s doesn't implement property "
"'%s' from interface '%s'",
g_type_name (G_OBJECT_CLASS_TYPE (class)),
pspecs[n]->name,
g_type_name (iface_type));
continue;
}
/* We do a number of checks on the properties of an interface to
* make sure that all classes implementing the interface are
* overriding the properties correctly.
*
* We do the checks in order of importance so that we can give
* more useful error messages first.
*
* First, we check that the implementation doesn't remove the
* basic functionality (readability, writability) advertised by
* the interface. Next, we check that it doesn't introduce
* additional restrictions (such as construct-only). Finally, we
* make sure the types are compatible.
*/
#define SUBSET(a,b,mask) (((a) & ~(b) & (mask)) == 0)
/* If the property on the interface is readable then the
* implementation must be readable. If the interface is writable
* then the implementation must be writable.
*/
if (!SUBSET (pspecs[n]->flags, class_pspec->flags, G_PARAM_READABLE | G_PARAM_WRITABLE))
{
g_critical ("Flags for property '%s' on class '%s' remove functionality compared with the "
"property on interface '%s'\n", pspecs[n]->name,
g_type_name (G_OBJECT_CLASS_TYPE (class)), g_type_name (iface_type));
continue;
}
/* If the property on the interface is writable then we need to
* make sure the implementation doesn't introduce new restrictions
* on that writability (ie: construct-only).
*
* If the interface was not writable to begin with then we don't
* really have any problems here because "writable at construct
* time only" is still more permissive than "read only".
*/
if (pspecs[n]->flags & G_PARAM_WRITABLE)
{
if (!SUBSET (class_pspec->flags, pspecs[n]->flags, G_PARAM_CONSTRUCT_ONLY))
{
g_critical ("Flags for property '%s' on class '%s' introduce additional restrictions on "
"writability compared with the property on interface '%s'\n", pspecs[n]->name,
g_type_name (G_OBJECT_CLASS_TYPE (class)), g_type_name (iface_type));
continue;
}
}
#undef SUBSET
/* If the property on the interface is readable then we are
* effectively advertising that reading the property will return a
* value of a specific type. All implementations of the interface
* need to return items of this type -- but may be more
* restrictive. For example, it is legal to have:
*
* GtkWidget *get_item();
*
* that is implemented by a function that always returns a
* GtkEntry. In short: readability implies that the
* implementation value type must be equal or more restrictive.
*
* Similarly, if the property on the interface is writable then
* must be able to accept the property being set to any value of
* that type, including subclasses. In this case, we may also be
* less restrictive. For example, it is legal to have:
*
* set_item (GtkEntry *);
*
* that is implemented by a function that will actually work with
* any GtkWidget. In short: writability implies that the
* implementation value type must be equal or less restrictive.
*
* In the case that the property is both readable and writable
* then the only way that both of the above can be satisfied is
* with a type that is exactly equal.
*/
switch (pspecs[n]->flags & (G_PARAM_READABLE | G_PARAM_WRITABLE))
{
case G_PARAM_READABLE | G_PARAM_WRITABLE:
/* class pspec value type must have exact equality with interface */
if (pspecs[n]->value_type != class_pspec->value_type)
g_critical ("Read/writable property '%s' on class '%s' has type '%s' which is not exactly equal to the "
"type '%s' of the property on the interface '%s'\n", pspecs[n]->name,
g_type_name (G_OBJECT_CLASS_TYPE (class)), g_type_name (G_PARAM_SPEC_VALUE_TYPE (class_pspec)),
g_type_name (G_PARAM_SPEC_VALUE_TYPE (pspecs[n])), g_type_name (iface_type));
break;
case G_PARAM_READABLE:
/* class pspec value type equal or more restrictive than interface */
if (!g_type_is_a (class_pspec->value_type, pspecs[n]->value_type))
g_critical ("Read-only property '%s' on class '%s' has type '%s' which is not equal to or more "
"restrictive than the type '%s' of the property on the interface '%s'\n", pspecs[n]->name,
g_type_name (G_OBJECT_CLASS_TYPE (class)), g_type_name (G_PARAM_SPEC_VALUE_TYPE (class_pspec)),
g_type_name (G_PARAM_SPEC_VALUE_TYPE (pspecs[n])), g_type_name (iface_type));
break;
case G_PARAM_WRITABLE:
/* class pspec value type equal or less restrictive than interface */
if (!g_type_is_a (pspecs[n]->value_type, class_pspec->value_type))
g_critical ("Write-only property '%s' on class '%s' has type '%s' which is not equal to or less "
"restrictive than the type '%s' of the property on the interface '%s' \n", pspecs[n]->name,
g_type_name (G_OBJECT_CLASS_TYPE (class)), g_type_name (G_PARAM_SPEC_VALUE_TYPE (class_pspec)),
g_type_name (G_PARAM_SPEC_VALUE_TYPE (pspecs[n])), g_type_name (iface_type));
break;
default:
g_assert_not_reached ();
}
}
g_free (pspecs);
out:
g_type_class_unref (class);
}
GType
g_object_get_type (void)
{
return G_TYPE_OBJECT;
}
/**
* g_object_new: (skip)
* @object_type: the type id of the #GObject subtype to instantiate
* @first_property_name: the name of the first property
* @...: the value of the first property, followed optionally by more
* name/value pairs, followed by %NULL
*
* Creates a new instance of a #GObject subtype and sets its properties.
*
* Construction parameters (see %G_PARAM_CONSTRUCT, %G_PARAM_CONSTRUCT_ONLY)
* which are not explicitly specified are set to their default values. Any
* private data for the object is guaranteed to be initialized with zeros, as
* per g_type_create_instance().
*
* Note that in C, small integer types in variable argument lists are promoted
* up to `gint` or `guint` as appropriate, and read back accordingly. `gint` is
* 32 bits on every platform on which GLib is currently supported. This means that
* you can use C expressions of type `gint` with g_object_new() and properties of
* type `gint` or `guint` or smaller. Specifically, you can use integer literals
* with these property types.
*
* When using property types of `gint64` or `guint64`, you must ensure that the
* value that you provide is 64 bit. This means that you should use a cast or
* make use of the %G_GINT64_CONSTANT or %G_GUINT64_CONSTANT macros.
*
* Similarly, `gfloat` is promoted to `gdouble`, so you must ensure that the value
* you provide is a `gdouble`, even for a property of type `gfloat`.
*
* Since GLib 2.72, all #GObjects are guaranteed to be aligned to at least the
* alignment of the largest basic GLib type (typically this is `guint64` or
* `gdouble`). If you need larger alignment for an element in a #GObject, you
* should allocate it on the heap (aligned), or arrange for your #GObject to be
* appropriately padded.
*
* Returns: (transfer full) (type GObject.Object): a new instance of
* @object_type
*/
gpointer
g_object_new (GType object_type,
const gchar *first_property_name,
...)
{
GObject *object;
va_list var_args;
/* short circuit for calls supplying no properties */
if (!first_property_name)
return g_object_new_with_properties (object_type, 0, NULL, 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;
}
/* Check alignment. (See https://gitlab.gnome.org/GNOME/glib/-/issues/1231.)
* This should never fail, since g_type_create_instance() uses g_slice_alloc0().
* The GSlice allocator always aligns to the next power of 2 greater than the
* allocation size. The allocation size for a GObject is
* sizeof(GTypeInstance) + sizeof(guint) + sizeof(GData*)
* which is 12B on 32-bit platforms, and larger on 64-bit systems. In both
* cases, that’s larger than the 8B needed for a guint64 or gdouble.
*
* If GSlice falls back to malloc(), it’s documented to return something
* suitably aligned for any basic type. */
static inline gboolean
g_object_is_aligned (GObject *object)
{
return ((((guintptr) (void *) object) %
MAX (G_ALIGNOF (gdouble),
MAX (G_ALIGNOF (guint64),
MAX (G_ALIGNOF (gint),
G_ALIGNOF (glong))))) == 0);
}
static gpointer
g_object_new_with_custom_constructor (GObjectClass *class,
GObjectConstructParam *params,
guint n_params)
{
GObjectNotifyQueue *nqueue = NULL;
gboolean newly_constructed;
GObjectConstructParam *cparams;
gboolean free_cparams = FALSE;
GObject *object;
GValue *cvalues;
gint cvals_used;
GSList *node;
guint i;
/* If we have ->constructed() then we have to do a lot more work.
* It's possible that this is a singleton and it's also possible
* that the user's constructor() will attempt to modify the values
* that we pass in, so we'll need to allocate copies of them.
* It's also possible that the user may attempt to call
* g_object_set() from inside of their constructor, so we need to
* add ourselves to a list of objects for which that is allowed
* while their constructor() is running.
*/
/* Create the array of GObjectConstructParams for constructor(),
* The 1024 here is an arbitrary, high limit that no sane code
* will ever hit, just to avoid the possibility of stack overflow.
*/
if (G_LIKELY (class->n_construct_properties < 1024))
{
cparams = g_newa0 (GObjectConstructParam, class->n_construct_properties);
cvalues = g_newa0 (GValue, class->n_construct_properties);
}
else
{
cparams = g_new0 (GObjectConstructParam, class->n_construct_properties);
cvalues = g_new0 (GValue, class->n_construct_properties);
free_cparams = TRUE;
}
cvals_used = 0;
i = 0;
/* As above, we may find the value in the passed-in params list.
*
* If we have the value passed in then we can use the GValue from
* it directly because it is safe to modify. If we use the
* default value from the class, we had better not pass that in
* and risk it being modified, so we create a new one.
* */
for (node = class->construct_properties; node; node = node->next)
{
GParamSpec *pspec;
GValue *value;
guint j;
pspec = node->data;
value = NULL; /* to silence gcc... */
for (j = 0; j < n_params; j++)
if (params[j].pspec == pspec)
{
consider_issuing_property_deprecation_warning (pspec);
value = params[j].value;
break;
}
if (value == NULL)
{
value = &cvalues[cvals_used++];
g_value_init (value, pspec->value_type);
g_param_value_set_default (pspec, value);
}
cparams[i].pspec = pspec;
cparams[i].value = value;
i++;
}
/* construct object from construction parameters */
object = class->constructor (class->g_type_class.g_type, class->n_construct_properties, cparams);
/* free construction values */
while (cvals_used--)
g_value_unset (&cvalues[cvals_used]);
if (free_cparams)
{
g_free (cparams);
g_free (cvalues);
}
/* There is code in the wild that relies on being able to return NULL
* from its custom constructor. This was never a supported operation,
* but since the code is already out there...
*/
if (object == NULL)
{
g_critical ("Custom constructor for class %s returned NULL (which is invalid). "
"Please use GInitable instead.", G_OBJECT_CLASS_NAME (class));
return NULL;
}
if (!g_object_is_aligned (object))
{
g_critical ("Custom constructor for class %s returned a non-aligned "
"GObject (which is invalid since GLib 2.72). Assuming any "
"code using this object doesn’t require it to be aligned. "
"Please fix your constructor to align to the largest GLib "
"basic type (typically gdouble or guint64).",
G_OBJECT_CLASS_NAME (class));
}
/* g_object_init() will have marked the object as being in-construction.
* Check if the returned object still is so marked, or if this is an
* already-existing singleton (in which case we should not do 'constructed').
*/
newly_constructed = object_in_construction (object);
if (newly_constructed)
unset_object_in_construction (object);
if (CLASS_HAS_PROPS (class))
{
if ((newly_constructed && _g_object_has_notify_handler (object)) ||
_g_object_has_notify_handler (object))
{
/* This may or may not have been setup in g_object_init().
* If it hasn't, we do it now.
*/
nqueue = g_datalist_id_get_data (&object->qdata, quark_notify_queue);
if (!nqueue)
nqueue = g_object_notify_queue_freeze (object);
}
}
/* run 'constructed' handler if there is a custom one */
if (newly_constructed && CLASS_HAS_CUSTOM_CONSTRUCTED (class))
class->constructed (object);
/* set remaining properties */
for (i = 0; i < n_params; i++)
if (!(params[i].pspec->flags & (G_PARAM_CONSTRUCT | G_PARAM_CONSTRUCT_ONLY)))
object_set_property (object, params[i].pspec, params[i].value, nqueue, TRUE);
/* If nqueue is non-NULL then we are frozen. Thaw it. */
if (nqueue)
g_object_notify_queue_thaw (object, nqueue, FALSE);
return object;
}
static gpointer
g_object_new_internal (GObjectClass *class,
GObjectConstructParam *params,
guint n_params)
{
GObjectNotifyQueue *nqueue = NULL;
GObject *object;
guint i;
if G_UNLIKELY (CLASS_HAS_CUSTOM_CONSTRUCTOR (class))
return g_object_new_with_custom_constructor (class, params, n_params);
object = (GObject *) g_type_create_instance (class->g_type_class.g_type);
g_assert (g_object_is_aligned (object));
unset_object_in_construction (object);
if (CLASS_HAS_PROPS (class))
{
GSList *node;
if (_g_object_has_notify_handler (object))
{
/* This may or may not have been setup in g_object_init().
* If it hasn't, we do it now.
*/
nqueue = g_datalist_id_get_data (&object->qdata, quark_notify_queue);
if (!nqueue)
nqueue = g_object_notify_queue_freeze (object);
}
/* We will set exactly n_construct_properties construct
* properties, but they may come from either the class default
* values or the passed-in parameter list.
*/
for (node = class->construct_properties; node; node = node->next)
{
const GValue *value;
GParamSpec *pspec;
guint j;
gboolean user_specified = FALSE;
pspec = node->data;
value = NULL; /* to silence gcc... */
for (j = 0; j < n_params; j++)
if (params[j].pspec == pspec)
{
value = params[j].value;
user_specified = TRUE;
break;
}
if (value == NULL)
value = g_param_spec_get_default_value (pspec);
object_set_property (object, pspec, value, nqueue, user_specified);
}
}
/* run 'constructed' handler if there is a custom one */
if (CLASS_HAS_CUSTOM_CONSTRUCTED (class))
class->constructed (object);
/* Set remaining properties. The construct properties will
* already have been taken, so set only the non-construct ones.
*/
for (i = 0; i < n_params; i++)
if (!(params[i].pspec->flags & (G_PARAM_CONSTRUCT | G_PARAM_CONSTRUCT_ONLY)))
object_set_property (object, params[i].pspec, params[i].value, nqueue, TRUE);
if (nqueue)
g_object_notify_queue_thaw (object, nqueue, FALSE);
return object;
}
static inline gboolean
g_object_new_is_valid_property (GType object_type,
GParamSpec *pspec,
const char *name,
GObjectConstructParam *params,
guint n_params)
{
guint i;
if (G_UNLIKELY (pspec == NULL))
{
g_critical ("%s: object class '%s' has no property named '%s'",
G_STRFUNC, g_type_name (object_type), name);
return FALSE;
}
if (G_UNLIKELY (~pspec->flags & G_PARAM_WRITABLE))
{
g_critical ("%s: property '%s' of object class '%s' is not writable",
G_STRFUNC, pspec->name, g_type_name (object_type));
return FALSE;
}
if (G_UNLIKELY (pspec->flags & (G_PARAM_CONSTRUCT | G_PARAM_CONSTRUCT_ONLY)))
{
for (i = 0; i < n_params; i++)
if (params[i].pspec == pspec)
break;
if (G_UNLIKELY (i != n_params))
{
g_critical ("%s: property '%s' for type '%s' cannot be set twice",
G_STRFUNC, name, g_type_name (object_type));
return FALSE;
}
}
return TRUE;
}
/**
* g_object_new_with_properties: (skip)
* @object_type: the object type to instantiate
* @n_properties: the number of properties
* @names: (array length=n_properties): the names of each property to be set
* @values: (array length=n_properties): the values of each property to be set
*
* Creates a new instance of a #GObject subtype and sets its properties using
* the provided arrays. Both arrays must have exactly @n_properties elements,
* and the names and values correspond by index.
*
* Construction parameters (see %G_PARAM_CONSTRUCT, %G_PARAM_CONSTRUCT_ONLY)
* which are not explicitly specified are set to their default values.
*
* Returns: (type GObject.Object) (transfer full): a new instance of
* @object_type
*
* Since: 2.54
*/
GObject *
g_object_new_with_properties (GType object_type,
guint n_properties,
const char *names[],
const GValue values[])
{
GObjectClass *class, *unref_class = NULL;
GObject *object;
g_return_val_if_fail (G_TYPE_IS_OBJECT (object_type), NULL);
/* Try to avoid thrashing the ref_count if we don't need to (since
* it's a locked operation).
*/
class = g_type_class_peek_static (object_type);
if (class == NULL)
class = unref_class = g_type_class_ref (object_type);
if (n_properties > 0)
{
guint i, count = 0;
GObjectConstructParam *params;
params = g_newa (GObjectConstructParam, n_properties);
for (i = 0; i < n_properties; i++)
{
GParamSpec *pspec = find_pspec (class, names[i]);
if (!g_object_new_is_valid_property (object_type, pspec, names[i], params, count))
continue;
params[count].pspec = pspec;
params[count].value = (GValue *) &values[i];
count++;
}
object = g_object_new_internal (class, params, count);
}
else
object = g_object_new_internal (class, NULL, 0);
if (unref_class != NULL)
g_type_class_unref (unref_class);
return object;
}
/**
* g_object_newv:
* @object_type: the type id of the #GObject subtype to instantiate
* @n_parameters: the length of the @parameters array
* @parameters: (array length=n_parameters): an array of #GParameter
*
* Creates a new instance of a #GObject subtype and sets its properties.
*
* Construction parameters (see %G_PARAM_CONSTRUCT, %G_PARAM_CONSTRUCT_ONLY)
* which are not explicitly specified are set to their default values.
*
* Returns: (type GObject.Object) (transfer full): a new instance of
* @object_type
*
* Deprecated: 2.54: Use g_object_new_with_properties() instead.
* deprecated. See #GParameter for more information.
*/
G_GNUC_BEGIN_IGNORE_DEPRECATIONS
gpointer
g_object_newv (GType object_type,
guint n_parameters,
GParameter *parameters)
{
GObjectClass *class, *unref_class = NULL;
GObject *object;
g_return_val_if_fail (G_TYPE_IS_OBJECT (object_type), NULL);
g_return_val_if_fail (n_parameters == 0 || parameters != NULL, NULL);
/* Try to avoid thrashing the ref_count if we don't need to (since
* it's a locked operation).
*/
class = g_type_class_peek_static (object_type);
if (!class)
class = unref_class = g_type_class_ref (object_type);
if (n_parameters)
{
GObjectConstructParam *cparams;
guint i, j;
cparams = g_newa (GObjectConstructParam, n_parameters);
j = 0;
for (i = 0; i < n_parameters; i++)
{
GParamSpec *pspec = find_pspec (class, parameters[i].name);
if (!g_object_new_is_valid_property (object_type, pspec, parameters[i].name, cparams, j))
continue;
cparams[j].pspec = pspec;
cparams[j].value = &parameters[i].value;
j++;
}
object = g_object_new_internal (class, cparams, j);
}
else
/* Fast case: no properties passed in. */
object = g_object_new_internal (class, NULL, 0);
if (unref_class)
g_type_class_unref (unref_class);
return object;
}
G_GNUC_END_IGNORE_DEPRECATIONS
/**
* g_object_new_valist: (skip)
* @object_type: the type id of the #GObject subtype to instantiate
* @first_property_name: the name of the first property
* @var_args: the value of the first property, followed optionally by more
* name/value pairs, followed by %NULL
*
* Creates a new instance of a #GObject subtype and sets its properties.
*
* Construction parameters (see %G_PARAM_CONSTRUCT, %G_PARAM_CONSTRUCT_ONLY)
* which are not explicitly specified are set to their default values.
*
* Returns: a new instance of @object_type
*/
GObject*
g_object_new_valist (GType object_type,
const gchar *first_property_name,
va_list var_args)
{
GObjectClass *class, *unref_class = NULL;
GObject *object;
g_return_val_if_fail (G_TYPE_IS_OBJECT (object_type), NULL);
/* Try to avoid thrashing the ref_count if we don't need to (since
* it's a locked operation).
*/
class = g_type_class_peek_static (object_type);
if (!class)
class = unref_class = g_type_class_ref (object_type);
if (first_property_name)
{
GObjectConstructParam params_stack[16];
GValue values_stack[G_N_ELEMENTS (params_stack)];
GTypeValueTable *vtabs_stack[G_N_ELEMENTS (params_stack)];
const gchar *name;
GObjectConstructParam *params = params_stack;
GValue *values = values_stack;
GTypeValueTable **vtabs = vtabs_stack;
guint n_params = 0;
guint n_params_alloc = G_N_ELEMENTS (params_stack);
name = first_property_name;
do
{
gchar *error = NULL;
GParamSpec *pspec = find_pspec (class, name);
if (!g_object_new_is_valid_property (object_type, pspec, name, params, n_params))
break;
if (G_UNLIKELY (n_params == n_params_alloc))
{
guint i;
if (n_params_alloc == G_N_ELEMENTS (params_stack))
{
n_params_alloc = G_N_ELEMENTS (params_stack) * 2u;
params = g_new (GObjectConstructParam, n_params_alloc);
values = g_new (GValue, n_params_alloc);
vtabs = g_new (GTypeValueTable *, n_params_alloc);
memcpy (params, params_stack, sizeof (GObjectConstructParam) * n_params);
memcpy (values, values_stack, sizeof (GValue) * n_params);
memcpy (vtabs, vtabs_stack, sizeof (GTypeValueTable *) * n_params);
}
else
{
n_params_alloc *= 2u;
params = g_realloc (params, sizeof (GObjectConstructParam) * n_params_alloc);
values = g_realloc (values, sizeof (GValue) * n_params_alloc);
vtabs = g_realloc (vtabs, sizeof (GTypeValueTable *) * n_params_alloc);
}
for (i = 0; i < n_params; i++)
params[i].value = &values[i];
}
params[n_params].pspec = pspec;
params[n_params].value = &values[n_params];
memset (&values[n_params], 0, sizeof (GValue));
G_VALUE_COLLECT_INIT2 (&values[n_params], vtabs[n_params], pspec->value_type, var_args, G_VALUE_NOCOPY_CONTENTS, &error);
if (error)
{
g_critical ("%s: %s", G_STRFUNC, error);
g_value_unset (&values[n_params]);
g_free (error);
break;
}
n_params++;
}
while ((name = va_arg (var_args, const gchar *)));
object = g_object_new_internal (class, params, n_params);
while (n_params--)
{
/* We open-code g_value_unset() here to avoid the
* cost of looking up the GTypeValueTable again.
*/
if (vtabs[n_params]->value_free)
vtabs[n_params]->value_free (params[n_params].value);
}
if (G_UNLIKELY (n_params_alloc != G_N_ELEMENTS (params_stack)))
{
g_free (params);
g_free (values);
g_free (vtabs);
}
}
else
/* Fast case: no properties passed in. */
object = g_object_new_internal (class, NULL, 0);
if (unref_class)
g_type_class_unref (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);
/* 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, FALSE);
}
g_object_notify_queue_thaw (object, nqueue, FALSE);
/* 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;
}
static void
g_object_constructed (GObject *object)
{
/* empty default impl to allow unconditional upchaining */
}
static inline gboolean
g_object_set_is_valid_property (GObject *object,
GParamSpec *pspec,
const char *property_name)
{
if (G_UNLIKELY (pspec == NULL))
{
g_critical ("%s: object class '%s' has no property named '%s'",
G_STRFUNC, G_OBJECT_TYPE_NAME (object), property_name);
return FALSE;
}
if (G_UNLIKELY (!(pspec->flags & G_PARAM_WRITABLE)))
{
g_critical ("%s: property '%s' of object class '%s' is not writable",
G_STRFUNC, pspec->name, G_OBJECT_TYPE_NAME (object));
return FALSE;
}
if (G_UNLIKELY (((pspec->flags & G_PARAM_CONSTRUCT_ONLY) && !object_in_construction (object))))
{
g_critical ("%s: construct property \"%s\" for object '%s' can't be set after construction",
G_STRFUNC, pspec->name, G_OBJECT_TYPE_NAME (object));
return FALSE;
}
return TRUE;
}
/**
* g_object_setv: (skip)
* @object: a #GObject
* @n_properties: the number of properties
* @names: (array length=n_properties): the names of each property to be set
* @values: (array length=n_properties): the values of each property to be set
*
* Sets @n_properties properties for an @object.
* Properties to be set will be taken from @values. All properties must be
* valid. Warnings will be emitted and undefined behaviour may result if invalid
* properties are passed in.
*
* Since: 2.54
*/
void
g_object_setv (GObject *object,
guint n_properties,
const gchar *names[],
const GValue values[])
{
guint i;
GObjectNotifyQueue *nqueue = NULL;
GParamSpec *pspec;
GObjectClass *class;
g_return_if_fail (G_IS_OBJECT (object));
if (n_properties == 0)
return;
g_object_ref (object);
class = G_OBJECT_GET_CLASS (object);
if (_g_object_has_notify_handler (object))
nqueue = g_object_notify_queue_freeze (object);
for (i = 0; i < n_properties; i++)
{
pspec = find_pspec (class, names[i]);
if (!g_object_set_is_valid_property (object, pspec, names[i]))
break;
object_set_property (object, pspec, &values[i], nqueue, TRUE);
}
if (nqueue)
g_object_notify_queue_thaw (object, nqueue, FALSE);
g_object_unref (object);
}
/**
* g_object_set_valist: (skip)
* @object: a #GObject
* @first_property_name: name of the first property to set
* @var_args: value for the first property, followed optionally by more
* name/value pairs, followed by %NULL
*
* Sets properties on an object.
*/
void
g_object_set_valist (GObject *object,
const gchar *first_property_name,
va_list var_args)
{
GObjectNotifyQueue *nqueue = NULL;
const gchar *name;
GObjectClass *class;
g_return_if_fail (G_IS_OBJECT (object));
g_object_ref (object);
if (_g_object_has_notify_handler (object))
nqueue = g_object_notify_queue_freeze (object);
class = G_OBJECT_GET_CLASS (object);
name = first_property_name;
while (name)
{
GValue value = G_VALUE_INIT;
GParamSpec *pspec;
gchar *error = NULL;
GTypeValueTable *vtab;
pspec = find_pspec (class, name);
if (!g_object_set_is_valid_property (object, pspec, name))
break;
G_VALUE_COLLECT_INIT2 (&value, vtab, pspec->value_type, var_args, G_VALUE_NOCOPY_CONTENTS, &error);
if (error)
{
g_critical ("%s: %s", G_STRFUNC, error);
g_free (error);
g_value_unset (&value);
break;
}
object_set_property (object, pspec, &value, nqueue, TRUE);
/* We open-code g_value_unset() here to avoid the
* cost of looking up the GTypeValueTable again.
*/
if (vtab->value_free)
vtab->value_free (&value);
name = va_arg (var_args, gchar*);
}
if (nqueue)
g_object_notify_queue_thaw (object, nqueue, FALSE);
g_object_unref (object);
}
static inline gboolean
g_object_get_is_valid_property (GObject *object,
GParamSpec *pspec,
const char *property_name)
{
if (G_UNLIKELY (pspec == NULL))
{
g_critical ("%s: object class '%s' has no property named '%s'",
G_STRFUNC, G_OBJECT_TYPE_NAME (object), property_name);
return FALSE;
}
if (G_UNLIKELY (!(pspec->flags & G_PARAM_READABLE)))
{
g_critical ("%s: property '%s' of object class '%s' is not readable",
G_STRFUNC, pspec->name, G_OBJECT_TYPE_NAME (object));
return FALSE;
}
return TRUE;
}
/**
* g_object_getv:
* @object: a #GObject
* @n_properties: the number of properties
* @names: (array length=n_properties): the names of each property to get
* @values: (array length=n_properties): the values of each property to get
*
* Gets @n_properties properties for an @object.
* Obtained properties will be set to @values. All properties must be valid.
* Warnings will be emitted and undefined behaviour may result if invalid
* properties are passed in.
*
* Since: 2.54
*/
void
g_object_getv (GObject *object,
guint n_properties,
const gchar *names[],
GValue values[])
{
guint i;
GParamSpec *pspec;
GObjectClass *class;
g_return_if_fail (G_IS_OBJECT (object));
if (n_properties == 0)
return;
g_object_ref (object);
class = G_OBJECT_GET_CLASS (object);
memset (values, 0, n_properties * sizeof (GValue));
for (i = 0; i < n_properties; i++)
{
pspec = find_pspec (class, names[i]);
if (!g_object_get_is_valid_property (object, pspec, names[i]))
break;
g_value_init (&values[i], pspec->value_type);
object_get_property (object, pspec, &values[i]);
}
g_object_unref (object);
}
/**
* g_object_get_valist: (skip)
* @object: a #GObject
* @first_property_name: name of the first property to get
* @var_args: return location for the first property, followed optionally by more
* name/return location pairs, followed by %NULL
*
* Gets properties of an object.
*
* In general, a copy is made of the property contents and the caller
* is responsible for freeing the memory in the appropriate manner for
* the type, for instance by calling g_free() or g_object_unref().
*
* See g_object_get().
*/
void
g_object_get_valist (GObject *object,
const gchar *first_property_name,
va_list var_args)
{
const gchar *name;
GObjectClass *class;
g_return_if_fail (G_IS_OBJECT (object));
g_object_ref (object);
class = G_OBJECT_GET_CLASS (object);
name = first_property_name;
while (name)
{
GValue value = G_VALUE_INIT;
GParamSpec *pspec;
gchar *error;
pspec = find_pspec (class, name);
if (!g_object_get_is_valid_property (object, pspec, name))
break;
g_value_init (&value, pspec->value_type);
object_get_property (object, pspec, &value);
G_VALUE_LCOPY (&value, var_args, 0, &error);
if (error)
{
g_critical ("%s: %s", G_STRFUNC, error);
g_free (error);
g_value_unset (&value);
break;
}
g_value_unset (&value);
name = va_arg (var_args, gchar*);
}
g_object_unref (object);
}
/**
* g_object_set: (skip)
* @object: (type GObject.Object): a #GObject
* @first_property_name: name of the first property to set
* @...: value for the first property, followed optionally by more
* name/value pairs, followed by %NULL
*
* Sets properties on an object.
*
* The same caveats about passing integer literals as varargs apply as with
* g_object_new(). In particular, any integer literals set as the values for
* properties of type #gint64 or #guint64 must be 64 bits wide, using the
* %G_GINT64_CONSTANT or %G_GUINT64_CONSTANT macros.
*
* Note that the "notify" signals are queued and only emitted (in
* reverse order) after all properties have been set. See
* g_object_freeze_notify().
*/
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);
}
/**
* g_object_get: (skip)
* @object: (type GObject.Object): a #GObject
* @first_property_name: name of the first property to get
* @...: return location for the first property, followed optionally by more
* name/return location pairs, followed by %NULL
*
* Gets properties of an object.
*
* In general, a copy is made of the property contents and the caller
* is responsible for freeing the memory in the appropriate manner for
* the type, for instance by calling g_free() or g_object_unref().
*
* Here is an example of using g_object_get() to get the contents
* of three properties: an integer, a string and an object:
* |[<!-- language="C" -->
* gint intval;
* guint64 uint64val;
* gchar *strval;
* GObject *objval;
*
* g_object_get (my_object,
* "int-property", &intval,
* "uint64-property", &uint64val,
* "str-property", &strval,
* "obj-property", &objval,
* NULL);
*
* // Do something with intval, uint64val, strval, objval
*
* g_free (strval);
* g_object_unref (objval);
* ]|
*/
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);
}
/**
* g_object_set_property:
* @object: a #GObject
* @property_name: the name of the property to set
* @value: the value
*
* Sets a property on an object.
*/
void
g_object_set_property (GObject *object,
const gchar *property_name,
const GValue *value)
{
g_object_setv (object, 1, &property_name, value);
}
/**
* g_object_get_property:
* @object: a #GObject
* @property_name: the name of the property to get
* @value: return location for the property value
*
* Gets a property of an object.
*
* The @value can be:
*
* - an empty #GValue initialized by %G_VALUE_INIT, which will be
* automatically initialized with the expected type of the property
* (since GLib 2.60)
* - a #GValue initialized with the expected type of the property
* - a #GValue initialized with a type to which the expected type
* of the property can be transformed
*
* In general, a copy is made of the property contents and the caller is
* responsible for freeing the memory by calling g_value_unset().
*
* Note that g_object_get_property() is really intended for language
* bindings, g_object_get() is much more convenient for C programming.
*/
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 (value != NULL);
g_object_ref (object);
pspec = find_pspec (G_OBJECT_GET_CLASS (object), property_name);
if (g_object_get_is_valid_property (object, pspec, property_name))
{
GValue *prop_value, tmp_value = G_VALUE_INIT;
if (G_VALUE_TYPE (value) == G_TYPE_INVALID)
{
/* zero-initialized value */
g_value_init (value, pspec->value_type);
prop_value = value;
}
else if (G_VALUE_TYPE (value) == pspec->value_type)
{
/* auto-conversion of the callers value type */
g_value_reset (value);
prop_value = value;
}
else if (!g_value_type_transformable (pspec->value_type, G_VALUE_TYPE (value)))
{
g_critical ("%s: can't retrieve property '%s' of type '%s' as value of type '%s'",
G_STRFUNC, pspec->name,
g_type_name (pspec->value_type),
G_VALUE_TYPE_NAME (value));
g_object_unref (object);
return;
}
else
{
g_value_init (&tmp_value, pspec->value_type);
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);
}
/**
* g_object_connect: (skip)
* @object: (type GObject.Object): a #GObject
* @signal_spec: the spec for the first signal
* @...: [type@GObject.Callback] for the first signal, followed by data for the
* first signal, followed optionally by more signal
* spec/callback/data triples, followed by `NULL`
*
* A convenience function to connect multiple signals at once.
*
* The signal specs expected by this function have the form
* `modifier::signal_name`, where `modifier` can be one of the
* following:
*
* - `signal`: equivalent to `g_signal_connect_data (..., NULL, G_CONNECT_DEFAULT)`
* - `object-signal`, `object_signal`: equivalent to `g_signal_connect_object (..., G_CONNECT_DEFAULT)`
* - `swapped-signal`, `swapped_signal`: equivalent to `g_signal_connect_data (..., NULL, G_CONNECT_SWAPPED)`
* - `swapped_object_signal`, `swapped-object-signal`: equivalent to `g_signal_connect_object (..., G_CONNECT_SWAPPED)`
* - `signal_after`, `signal-after`: equivalent to `g_signal_connect_data (..., NULL, G_CONNECT_AFTER)`
* - `object_signal_after`, `object-signal-after`: equivalent to `g_signal_connect_object (..., G_CONNECT_AFTER)`
* - `swapped_signal_after`, `swapped-signal-after`: equivalent to `g_signal_connect_data (..., NULL, G_CONNECT_SWAPPED | G_CONNECT_AFTER)`
* - `swapped_object_signal_after`, `swapped-object-signal-after`: equivalent to `g_signal_connect_object (..., G_CONNECT_SWAPPED | G_CONNECT_AFTER)`
*
* ```c
* menu->toplevel = g_object_connect (g_object_new (GTK_TYPE_WINDOW,
* "type", GTK_WINDOW_POPUP,
* "child", menu,
* NULL),
* "signal::event", gtk_menu_window_event, menu,
* "signal::size_request", gtk_menu_window_size_request, menu,
* "signal::destroy", gtk_widget_destroyed, &menu->toplevel,
* NULL);
* ```
*
* Returns: (transfer none) (type GObject.Object): the 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);
if (strncmp (signal_spec, "signal::", 8) == 0)
g_signal_connect_data (object, signal_spec + 8,
callback, data, NULL,
G_CONNECT_DEFAULT);
else if (strncmp (signal_spec, "object_signal::", 15) == 0 ||
strncmp (signal_spec, "object-signal::", 15) == 0)
g_signal_connect_object (object, signal_spec + 15,
callback, data,
G_CONNECT_DEFAULT);
else if (strncmp (signal_spec, "swapped_signal::", 16) == 0 ||
strncmp (signal_spec, "swapped-signal::", 16) == 0)
g_signal_connect_data (object, signal_spec + 16,
callback, data, NULL,
G_CONNECT_SWAPPED);
else if (strncmp (signal_spec, "swapped_object_signal::", 23) == 0 ||
strncmp (signal_spec, "swapped-object-signal::", 23) == 0)
g_signal_connect_object (object, signal_spec + 23,
callback, data,
G_CONNECT_SWAPPED);
else if (strncmp (signal_spec, "signal_after::", 14) == 0 ||
strncmp (signal_spec, "signal-after::", 14) == 0)
g_signal_connect_data (object, signal_spec + 14,
callback, data, NULL,
G_CONNECT_AFTER);
else if (strncmp (signal_spec, "object_signal_after::", 21) == 0 ||
strncmp (signal_spec, "object-signal-after::", 21) == 0)
g_signal_connect_object (object, signal_spec + 21,
callback, data,
G_CONNECT_AFTER);
else if (strncmp (signal_spec, "swapped_signal_after::", 22) == 0 ||
strncmp (signal_spec, "swapped-signal-after::", 22) == 0)
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 ||
strncmp (signal_spec, "swapped-object-signal-after::", 29) == 0)
g_signal_connect_object (object, signal_spec + 29,
callback, data,
G_CONNECT_SWAPPED | G_CONNECT_AFTER);
else
{
g_critical ("%s: invalid signal spec \"%s\"", G_STRFUNC, signal_spec);
break;
}
signal_spec = va_arg (var_args, gchar*);
}
va_end (var_args);
return object;
}
/**
* g_object_disconnect: (skip)
* @object: (type GObject.Object): a #GObject
* @signal_spec: the spec for the first signal
* @...: #GCallback for the first signal, followed by data for the first signal,
* followed optionally by more signal spec/callback/data triples,
* followed by %NULL
*
* A convenience function to disconnect multiple signals at once.
*
* The signal specs expected by this function have the form
* "any_signal", which means to disconnect any signal with matching
* callback and data, or "any_signal::signal_name", which only
* disconnects the signal named "signal_name".
*/
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 ||
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 ||
strcmp (signal_spec, "any-signal") == 0)
{
signal_spec += 10;
mask = G_SIGNAL_MATCH_FUNC | G_SIGNAL_MATCH_DATA;
}
else
{
g_critical ("%s: invalid signal spec \"%s\"", G_STRFUNC, signal_spec);
break;
}
if ((mask & G_SIGNAL_MATCH_ID) &&
!g_signal_parse_name (signal_spec, G_OBJECT_TYPE (object), &sid, &detail, FALSE))
g_critical ("%s: invalid signal name \"%s\"", G_STRFUNC, signal_spec);
else if (!g_signal_handlers_disconnect_matched (object, mask | (detail ? G_SIGNAL_MATCH_DETAIL : 0),
sid, detail,
NULL, (gpointer)callback, data))
g_critical ("%s: signal handler %p(%p) is not connected", G_STRFUNC, 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);
}
/**
* g_object_weak_ref: (skip)
* @object: #GObject to reference weakly
* @notify: callback to invoke before the object is freed
* @data: extra data to pass to notify
*
* Adds a weak reference callback to an object. Weak references are
* used for notification when an object is disposed. They are called
* "weak references" because they allow you to safely hold a pointer
* to an object without calling g_object_ref() (g_object_ref() adds a
* strong reference, that is, forces the object to stay alive).
*
* Note that the weak references created by this method are not
* thread-safe: they cannot safely be used in one thread if the
* object's last g_object_unref() might happen in another thread.
* Use #GWeakRef if thread-safety is required.
*/
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 (g_atomic_int_get (&object->ref_count) >= 1);
object_bit_lock (object, OPTIONAL_BIT_LOCK_WEAK_REFS);
wstack = g_datalist_id_remove_no_notify (&object->qdata, quark_weak_notifies);
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_notifies, wstack, weak_refs_notify);
object_bit_unlock (object, OPTIONAL_BIT_LOCK_WEAK_REFS);
}
/**
* g_object_weak_unref: (skip)
* @object: #GObject to remove a weak reference from
* @notify: callback to search for
* @data: data to search for
*
* Removes a weak reference callback to an object.
*/
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);
object_bit_lock (object, OPTIONAL_BIT_LOCK_WEAK_REFS);
wstack = g_datalist_id_get_data (&object->qdata, quark_weak_notifies);
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] = wstack->weak_refs[wstack->n_weak_refs];
break;
}
}
object_bit_unlock (object, OPTIONAL_BIT_LOCK_WEAK_REFS);
if (!found_one)
g_critical ("%s: couldn't find weak ref %p(%p)", G_STRFUNC, notify, data);
}
/**
* g_object_add_weak_pointer: (skip)
* @object: The object that should be weak referenced.
* @weak_pointer_location: (inout) (not optional): The memory address
* of a pointer.
*
* Adds a weak reference from weak_pointer to @object to indicate that
* the pointer located at @weak_pointer_location is only valid during
* the lifetime of @object. When the @object is finalized,
* @weak_pointer will be set to %NULL.
*
* Note that as with g_object_weak_ref(), the weak references created by
* this method are not thread-safe: they cannot safely be used in one
* thread if the object's last g_object_unref() might happen in another
* thread. Use #GWeakRef if thread-safety is required.
*/
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);
}
/**
* g_object_remove_weak_pointer: (skip)
* @object: The object that is weak referenced.
* @weak_pointer_location: (inout) (not optional): The memory address
* of a pointer.
*
* Removes a weak reference from @object that was previously added
* using g_object_add_weak_pointer(). The @weak_pointer_location has
* to match the one used with g_object_add_weak_pointer().
*/
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);
}
static guint
object_floating_flag_handler (GObject *object,
gint job)
{
switch (job)
{
gpointer oldvalue;
case +1: /* force floating if possible */
oldvalue = g_atomic_pointer_get (&object->qdata);
while (!g_atomic_pointer_compare_and_exchange_full (
(void**) &object->qdata, oldvalue,
(void *) ((guintptr) oldvalue | OBJECT_FLOATING_FLAG),
&oldvalue))
;
return (gsize) oldvalue & OBJECT_FLOATING_FLAG;
case -1: /* sink if possible */
oldvalue = g_atomic_pointer_get (&object->qdata);
while (!g_atomic_pointer_compare_and_exchange_full (
(void**) &object->qdata, oldvalue,
(void *) ((guintptr) oldvalue & ~(gsize) OBJECT_FLOATING_FLAG),
&oldvalue))
;
return (gsize) oldvalue & OBJECT_FLOATING_FLAG;
default: /* check floating */
return 0 != ((gsize) g_atomic_pointer_get (&object->qdata) & OBJECT_FLOATING_FLAG);
}
}
/**
* g_object_is_floating:
* @object: (type GObject.Object): a #GObject
*
* Checks whether @object has a [floating][floating-ref] reference.
*
* Since: 2.10
*
* Returns: %TRUE if @object has a floating reference
*/
gboolean
g_object_is_floating (gpointer _object)
{
GObject *object = _object;
g_return_val_if_fail (G_IS_OBJECT (object), FALSE);
return floating_flag_handler (object, 0);
}
/**
* g_object_ref_sink:
* @object: (type GObject.Object): a #GObject
*
* Increase the reference count of @object, and possibly remove the
* [floating][floating-ref] reference, if @object has a floating reference.
*
* In other words, if the object is floating, then this call "assumes
* ownership" of the floating reference, converting it to a normal
* reference by clearing the floating flag while leaving the reference
* count unchanged. If the object is not floating, then this call
* adds a new normal reference increasing the reference count by one.
*
* Since GLib 2.56, the type of @object will be propagated to the return type
* under the same conditions as for g_object_ref().
*
* Since: 2.10
*
* Returns: (type GObject.Object) (transfer none): @object
*/
gpointer
(g_object_ref_sink) (gpointer _object)
{
GObject *object = _object;
gboolean was_floating;
g_return_val_if_fail (G_IS_OBJECT (object), object);
g_return_val_if_fail (g_atomic_int_get (&object->ref_count) >= 1, object);
g_object_ref (object);
was_floating = floating_flag_handler (object, -1);
if (was_floating)
g_object_unref (object);
return object;
}
/**
* g_object_take_ref: (skip)
* @object: (type GObject.Object): a #GObject
*
* If @object is floating, sink it. Otherwise, do nothing.
*
* In other words, this function will convert a floating reference (if
* present) into a full reference.
*
* Typically you want to use g_object_ref_sink() in order to
* automatically do the correct thing with respect to floating or
* non-floating references, but there is one specific scenario where
* this function is helpful.
*
* The situation where this function is helpful is when creating an API
* that allows the user to provide a callback function that returns a
* GObject. We certainly want to allow the user the flexibility to
* return a non-floating reference from this callback (for the case
* where the object that is being returned already exists).
*
* At the same time, the API style of some popular GObject-based
* libraries (such as Gtk) make it likely that for newly-created GObject
* instances, the user can be saved some typing if they are allowed to
* return a floating reference.
*
* Using this function on the return value of the user's callback allows
* the user to do whichever is more convenient for them. The caller will
* always receives exactly one full reference to the value: either the
* one that was returned in the first place, or a floating reference
* that has been converted to a full reference.
*
* This function has an odd interaction when combined with
* g_object_ref_sink() running at the same time in another thread on
* the same #GObject instance. If g_object_ref_sink() runs first then
* the result will be that the floating reference is converted to a hard
* reference. If g_object_take_ref() runs first then the result will be
* that the floating reference is converted to a hard reference and an
* additional reference on top of that one is added. It is best to avoid
* this situation.
*
* Since: 2.70
*
* Returns: (type GObject.Object) (transfer full): @object
*/
gpointer
g_object_take_ref (gpointer _object)
{
GObject *object = _object;
g_return_val_if_fail (G_IS_OBJECT (object), object);
g_return_val_if_fail (g_atomic_int_get (&object->ref_count) >= 1, object);
floating_flag_handler (object, -1);
return object;
}
/**
* g_object_force_floating:
* @object: a #GObject
*
* This function is intended for #GObject implementations to re-enforce
* a [floating][floating-ref] object reference. Doing this is seldom
* required: all #GInitiallyUnowneds are created with a floating reference
* which usually just needs to be sunken by calling g_object_ref_sink().
*
* Since: 2.10
*/
void
g_object_force_floating (GObject *object)
{
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (g_atomic_int_get (&object->ref_count) >= 1);
floating_flag_handler (object, +1);
}
typedef struct {
guint n_toggle_refs;
struct {
GToggleNotify notify;
gpointer data;
} toggle_refs[1]; /* flexible array */
} ToggleRefStack;
G_ALWAYS_INLINE static inline gboolean
toggle_refs_check_and_ref_or_deref (GObject *object,
gboolean is_ref,
gint *old_ref,
GToggleNotify *toggle_notify,
gpointer *toggle_data)
{
const gint ref_curr = is_ref ? 1 : 2;
const gint ref_next = is_ref ? 2 : 1;
gboolean success;
#if G_ENABLE_DEBUG
g_assert (ref_curr == *old_ref);
#endif
*toggle_notify = NULL;
*toggle_data = NULL;
object_bit_lock (object, OPTIONAL_BIT_LOCK_TOGGLE_REFS);
/* @old_ref is mainly an (out) parameter. On failure to compare-and-exchange,
* we MUST return the new value which the caller will use for retry.*/
success = g_atomic_int_compare_and_exchange_full ((int *) &object->ref_count,
ref_curr,
ref_next,
old_ref);
/* Note that if we are called during g_object_unref (@is_ref set to FALSE),
* then we drop the ref count from 2 to 1 and give up our reference. We thus
* no longer hold a strong reference and another thread may race against
* destroying the object.
*
* After this point with is_ref=FALSE and success=TRUE, @object must no
* longer be accessed.
*
* The exception is here. While we still hold the object lock, we know that
* @object could not be destroyed, because g_object_unref() also needs to
* acquire the same lock during g_object_notify_queue_freeze(). Thus, we know
* object cannot yet be destroyed and we can access it until the unlock
* below. */
if (success && OBJECT_HAS_TOGGLE_REF (object))
{
ToggleRefStack *tstackptr;
tstackptr = g_datalist_id_get_data (&object->qdata, quark_toggle_refs);
if (tstackptr->n_toggle_refs != 1)
{
g_critical ("Unexpected number of toggle-refs. g_object_add_toggle_ref() must be paired with g_object_remove_toggle_ref()");
}
else
{
*toggle_notify = tstackptr->toggle_refs[0].notify;
*toggle_data = tstackptr->toggle_refs[0].data;
}
}
object_bit_unlock (object, OPTIONAL_BIT_LOCK_TOGGLE_REFS);
return success;
}
/**
* g_object_add_toggle_ref: (skip)
* @object: a #GObject
* @notify: a function to call when this reference is the
* last reference to the object, or is no longer
* the last reference.
* @data: data to pass to @notify
*
* Increases the reference count of the object by one and sets a
* callback to be called when all other references to the object are
* dropped, or when this is already the last reference to the object
* and another reference is established.
*
* This functionality is intended for binding @object to a proxy
* object managed by another memory manager. This is done with two
* paired references: the strong reference added by
* g_object_add_toggle_ref() and a reverse reference to the proxy
* object which is either a strong reference or weak reference.
*
* The setup is that when there are no other references to @object,
* only a weak reference is held in the reverse direction from @object
* to the proxy object, but when there are other references held to
* @object, a strong reference is held. The @notify callback is called
* when the reference from @object to the proxy object should be
* "toggled" from strong to weak (@is_last_ref true) or weak to strong
* (@is_last_ref false).
*
* Since a (normal) reference must be held to the object before
* calling g_object_add_toggle_ref(), the initial state of the reverse
* link is always strong.
*
* Multiple toggle references may be added to the same gobject,
* however if there are multiple toggle references to an object, none
* of them will ever be notified until all but one are removed. For
* this reason, you should only ever use a toggle reference if there
* is important state in the proxy object.
*
* Note that if you unref the object on another thread, then @notify might
* still be invoked after g_object_remove_toggle_ref(), and the object argument
* might be a dangling pointer. If the object is destroyed on other threads,
* you must take care of that yourself.
*
* A g_object_add_toggle_ref() must be released with g_object_remove_toggle_ref().
*
* Since: 2.8
*/
void
g_object_add_toggle_ref (GObject *object,
GToggleNotify notify,
gpointer data)
{
ToggleRefStack *tstack;
guint i;
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (notify != NULL);
g_return_if_fail (g_atomic_int_get (&object->ref_count) >= 1);
g_object_ref (object);
object_bit_lock (object, OPTIONAL_BIT_LOCK_TOGGLE_REFS);
tstack = g_datalist_id_remove_no_notify (&object->qdata, quark_toggle_refs);
if (tstack)
{
i = tstack->n_toggle_refs++;
/* allocate i = tstate->n_toggle_refs - 1 positions beyond the 1 declared
* in tstate->toggle_refs */
tstack = g_realloc (tstack, sizeof (*tstack) + sizeof (tstack->toggle_refs[0]) * i);
}
else
{
tstack = g_renew (ToggleRefStack, NULL, 1);
tstack->n_toggle_refs = 1;
i = 0;
}
/* Set a flag for fast lookup after adding the first toggle reference */
if (tstack->n_toggle_refs == 1)
g_datalist_set_flags (&object->qdata, OBJECT_HAS_TOGGLE_REF_FLAG);
tstack->toggle_refs[i].notify = notify;
tstack->toggle_refs[i].data = data;
g_datalist_id_set_data_full (&object->qdata, quark_toggle_refs, tstack,
(GDestroyNotify)g_free);
object_bit_unlock (object, OPTIONAL_BIT_LOCK_TOGGLE_REFS);
}
/**
* g_object_remove_toggle_ref: (skip)
* @object: a #GObject
* @notify: a function to call when this reference is the
* last reference to the object, or is no longer
* the last reference.
* @data: (nullable): data to pass to @notify, or %NULL to
* match any toggle refs with the @notify argument.
*
* Removes a reference added with g_object_add_toggle_ref(). The
* reference count of the object is decreased by one.
*
* Note that if you unref the object on another thread, then @notify might
* still be invoked after g_object_remove_toggle_ref(), and the object argument
* might be a dangling pointer. If the object is destroyed on other threads,
* you must take care of that yourself.
*
* Since: 2.8
*/
void
g_object_remove_toggle_ref (GObject *object,
GToggleNotify notify,
gpointer data)
{
ToggleRefStack *tstack;
gboolean found_one = FALSE;
g_return_if_fail (G_IS_OBJECT (object));
g_return_if_fail (notify != NULL);
object_bit_lock (object, OPTIONAL_BIT_LOCK_TOGGLE_REFS);
tstack = g_datalist_id_get_data (&object->qdata, quark_toggle_refs);
if (tstack)
{
guint i;
for (i = 0; i < tstack->n_toggle_refs; i++)
if (tstack->toggle_refs[i].notify == notify &&
(tstack->toggle_refs[i].data == data || data == NULL))
{
found_one = TRUE;
tstack->n_toggle_refs -= 1;
if (i != tstack->n_toggle_refs)
tstack->toggle_refs[i] = tstack->toggle_refs[tstack->n_toggle_refs];
if (tstack->n_toggle_refs == 0)
{
g_datalist_unset_flags (&object->qdata, OBJECT_HAS_TOGGLE_REF_FLAG);
g_datalist_id_set_data_full (&object->qdata, quark_toggle_refs, NULL, NULL);
}
break;
}
}
object_bit_unlock (object, OPTIONAL_BIT_LOCK_TOGGLE_REFS);
if (found_one)
g_object_unref (object);
else
g_critical ("%s: couldn't find toggle ref %p(%p)", G_STRFUNC, notify, data);
}
/* Internal implementation of g_object_ref() which doesn't call out to user code.
* @out_toggle_notify and @out_toggle_data *must* be provided, and if non-`NULL`
* values are returned, then the caller *must* call that toggle notify function
* as soon as it is safe to do so. It may call (or be) user-provided code so should
* only be called once all locks are released. */
static gpointer
object_ref (GObject *object,
GToggleNotify *out_toggle_notify,
gpointer *out_toggle_data)
{
GToggleNotify toggle_notify;
gpointer toggle_data;
gint old_ref;
old_ref = g_atomic_int_get (&object->ref_count);
retry:
toggle_notify = NULL;
toggle_data = NULL;
if (old_ref > 1 && old_ref < G_MAXINT)
{
/* Fast-path. We have apparently more than 1 references already. No
* special handling for toggle references, just increment the ref count. */
if (!g_atomic_int_compare_and_exchange_full ((int *) &object->ref_count,
old_ref, old_ref + 1, &old_ref))
goto retry;
}
else if (old_ref == 1)
{
/* With ref count 1, check whether we need to emit a toggle notification. */
if (!toggle_refs_check_and_ref_or_deref (object, TRUE, &old_ref, &toggle_notify, &toggle_data))
goto retry;
}
else
{
gboolean object_already_finalized = TRUE;
*out_toggle_notify = NULL;
*out_toggle_data = NULL;
g_return_val_if_fail (!object_already_finalized, NULL);
return NULL;
}
TRACE (GOBJECT_OBJECT_REF (object, G_TYPE_FROM_INSTANCE (object), old_ref));
*out_toggle_notify = toggle_notify;
*out_toggle_data = toggle_data;
return object;
}
/**
* g_object_ref:
* @object: (type GObject.Object): a #GObject
*
* Increases the reference count of @object.
*
* Since GLib 2.56, if `GLIB_VERSION_MAX_ALLOWED` is 2.56 or greater, the type
* of @object will be propagated to the return type (using the GCC typeof()
* extension), so any casting the caller needs to do on the return type must be
* explicit.
*
* Returns: (type GObject.Object) (transfer none): the same @object
*/
gpointer
(g_object_ref) (gpointer _object)
{
GObject *object = _object;
GToggleNotify toggle_notify;
gpointer toggle_data;
g_return_val_if_fail (G_IS_OBJECT (object), NULL);
object = object_ref (object, &toggle_notify, &toggle_data);
if (toggle_notify)
toggle_notify (toggle_data, object, FALSE);
return object;
}
static gboolean
_object_unref_clear_weak_locations (GObject *object, gint *p_old_ref, gboolean do_unref)
{
WeakRefData *wrdata;
gboolean success;
/* Fast path, for objects that never had a GWeakRef registered. */
if (!(object_get_optional_flags (object) & OPTIONAL_FLAG_EVER_HAD_WEAK_REF))
{
/* The caller previously just checked atomically that the ref-count was
* one.
*
* At this point still, @object never ever had a GWeakRef registered.
* That means, nobody else holds a strong reference and also nobody else
* can hold a weak reference, to race against obtaining another
* reference. We are good to proceed. */
if (do_unref)
{
if (!g_atomic_int_compare_and_exchange ((gint *) &object->ref_count, 1, 0))
{
#if G_ENABLE_DEBUG
g_assert_not_reached ();
#endif
}
}
return TRUE;
}
/* Slow path. We must obtain a lock on the @wrdata, to atomically release
* weak references and check that the ref count is as expected. */
wrdata = weak_ref_data_get_surely (object);
weak_ref_data_lock (wrdata);
if (do_unref)
{
success = g_atomic_int_compare_and_exchange_full ((gint *) &object->ref_count,
1, 0,
p_old_ref);
}
else
{
*p_old_ref = g_atomic_int_get ((gint *) &object->ref_count);
success = (*p_old_ref == 1);
}
if (success)
weak_ref_data_clear_list (wrdata, object);
weak_ref_data_unlock (wrdata);
return success;
}
/**
* g_object_unref:
* @object: (type GObject.Object): a #GObject
*
* Decreases the reference count of @object. When its reference count
* drops to 0, the object is finalized (i.e. its memory is freed).
*
* If the pointer to the #GObject may be reused in future (for example, if it is
* an instance variable of another object), it is recommended to clear the
* pointer to %NULL rather than retain a dangling pointer to a potentially
* invalid #GObject instance. Use g_clear_object() for this.
*/
void
g_object_unref (gpointer _object)
{
GObject *object = _object;
gint old_ref;
GToggleNotify toggle_notify;
gpointer toggle_data;
GObjectNotifyQueue *nqueue;
GType obj_gtype;
g_return_if_fail (G_IS_OBJECT (object));
/* obj_gtype will be needed for TRACE(GOBJECT_OBJECT_UNREF()) later. Note
* that we issue the TRACE() after decrementing the ref-counter. If at that
* point the reference counter does not reach zero, somebody else can race
* and destroy the object.
*
* This means, TRACE() can be called with a dangling object pointer. This
* could only be avoided, by emitting the TRACE before doing the actual
* unref, but at that point we wouldn't know the correct "old_ref" value.
* Maybe this should change.
*
* Anyway. At that later point we can also no longer safely get the GType for
* the TRACE(). Do it now.
*/
obj_gtype = G_TYPE_FROM_INSTANCE (object);
(void) obj_gtype;
old_ref = g_atomic_int_get (&object->ref_count);
retry_beginning:
if (old_ref > 2)
{
/* We have many references. If we can decrement the ref counter, we are done. */
if (!g_atomic_int_compare_and_exchange_full ((int *) &object->ref_count,
old_ref, old_ref - 1, &old_ref))
goto retry_beginning;
/* Beware: object might be a dangling pointer. */
TRACE (GOBJECT_OBJECT_UNREF (object, obj_gtype, old_ref));
return;
}
if (old_ref == 2)
{
/* We are about to return the second-to-last reference. In that case we
* might need to notify a toggle reference.
*
* Note that a g_object_add_toggle_ref() MUST always be released
* via g_object_remove_toggle_ref(). Thus, if we are here with
* an old_ref of 2, then at most one of the references can be
* a toggle reference.
*
* We need to take a lock, to avoid races. */
if (!toggle_refs_check_and_ref_or_deref (object, FALSE, &old_ref, &toggle_notify, &toggle_data))
goto retry_beginning;
/* Beware: object might be a dangling pointer. */
TRACE (GOBJECT_OBJECT_UNREF (object, obj_gtype, old_ref));
if (toggle_notify)
toggle_notify (toggle_data, object, TRUE);
return;
}
if (G_UNLIKELY (old_ref != 1))
{
gboolean object_already_finalized = TRUE;
g_return_if_fail (!object_already_finalized);
return;
}
/* We only have one reference left. Proceed to (maybe) clear weak locations. */
if (!_object_unref_clear_weak_locations (object, &old_ref, FALSE))
goto retry_beginning;
/* At this point, we checked with an atomic read that we only hold only one
* reference. Weak locations are cleared (and toggle references are not to
* be considered in this case). Proceed with dispose().
*
* First, freeze the notification queue, so we don't accidentally emit
* notifications during dispose() and finalize().
*
* The notification queue stays frozen unless the instance acquires a
* reference during dispose(), in which case we thaw it and dispatch all the
* notifications. If the instance gets through to finalize(), the
* notification queue gets automatically drained when g_object_finalize() is
* reached and the qdata is cleared.
*
* Important: Note that g_object_notify_queue_freeze() takes a object_bit_lock(),
* which happens to be the same lock that is also taken by toggle_refs_check_and_ref(),
* that is very important. See also the code comment in toggle_refs_check_and_ref().
*/
nqueue = g_object_notify_queue_freeze (object);
TRACE (GOBJECT_OBJECT_DISPOSE (object, G_TYPE_FROM_INSTANCE (object), 1));
G_OBJECT_GET_CLASS (object)->dispose (object);
TRACE (GOBJECT_OBJECT_DISPOSE_END (object, G_TYPE_FROM_INSTANCE (object), 1));
/* Must re-fetch old-ref. _object_unref_clear_weak_locations() relies on
* that. */
old_ref = g_atomic_int_get (&object->ref_count);
retry_decrement:
/* Here, old_ref is 1 if we just come from dispose(). If the object was resurrected,
* we can hit `goto retry_decrement` and be here with a larger old_ref. */
if (old_ref > 1 && nqueue)
{
/* If the object was resurrected, we need to unfreeze the notify
* queue. */
g_object_notify_queue_thaw (object, nqueue, FALSE);
nqueue = NULL;
/* Note at this point, @old_ref might be wrong.
*
* Also note that _object_unref_clear_weak_locations() requires that we
* atomically checked that @old_ref is 1. However, as @old_ref is larger
* than 1, that will not be called. Instead, all other code paths below,
* handle the possibility of a bogus @old_ref.
*
* No need to re-fetch. */
}
if (old_ref > 2)
{
if (!g_atomic_int_compare_and_exchange_full ((int *) &object->ref_count,
old_ref, old_ref - 1,
&old_ref))
goto retry_decrement;
/* Beware: object might be a dangling pointer. */
TRACE (GOBJECT_OBJECT_UNREF (object, obj_gtype, old_ref));
return;
}
if (old_ref == 2)
{
/* If the object was resurrected and the current ref-count is 2, then we
* are about to drop the ref-count to 1. We may need to emit a toggle
* notification. Take a lock and check for that.
*
* In that case, we need a lock to get the toggle notification. */
if (!toggle_refs_check_and_ref_or_deref (object, FALSE, &old_ref, &toggle_notify, &toggle_data))
goto retry_decrement;
/* Beware: object might be a dangling pointer. */
TRACE (GOBJECT_OBJECT_UNREF (object, obj_gtype, old_ref));
if (toggle_notify)
toggle_notify (toggle_data, object, TRUE);
return;
}
/* old_ref is (atomically!) checked to be 1, we are about to drop the
* reference count to zero in _object_unref_clear_weak_locations(). */
if (!_object_unref_clear_weak_locations (object, &old_ref, TRUE))
goto retry_decrement;
TRACE (GOBJECT_OBJECT_UNREF (object, obj_gtype, old_ref));
/* The object is almost gone. Finalize. */
g_datalist_id_set_data (&object->qdata, quark_closure_array, NULL);
g_signal_handlers_destroy (object);
g_datalist_id_set_data (&object->qdata, quark_weak_notifies, NULL);
TRACE (GOBJECT_OBJECT_FINALIZE (object, G_TYPE_FROM_INSTANCE (object)));
G_OBJECT_GET_CLASS (object)->finalize (object);
TRACE (GOBJECT_OBJECT_FINALIZE_END (object, G_TYPE_FROM_INSTANCE (object)));
GOBJECT_IF_DEBUG (OBJECTS,
{
gboolean was_present;
/* catch objects not chaining finalize handlers */
G_LOCK (debug_objects);
was_present = g_hash_table_remove (debug_objects_ht, object);
G_UNLOCK (debug_objects);
if (was_present)
g_critical ("Object %p of type %s not finalized correctly.",
object, G_OBJECT_TYPE_NAME (object));
});
g_type_free_instance ((GTypeInstance *) object);
}
/**
* g_clear_object: (skip)
* @object_ptr: a pointer to a #GObject reference
*
* Clears a reference to a #GObject.
*
* @object_ptr must not be %NULL.
*
* If the reference is %NULL then this function does nothing.
* Otherwise, the reference count of the object is decreased and the
* pointer is set to %NULL.
*
* A macro is also included that allows this function to be used without
* pointer casts.
*
* Since: 2.28
**/
#undef g_clear_object
void
g_clear_object (GObject **object_ptr)
{
g_clear_pointer (object_ptr, g_object_unref);
}
/**
* g_object_get_qdata:
* @object: The GObject to get a stored user data pointer from
* @quark: A #GQuark, naming the user data pointer
*
* This function gets back user data pointers stored via
* g_object_set_qdata().
*
* Returns: (transfer none) (nullable): The user data pointer set, or %NULL
*/
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;
}
/**
* g_object_set_qdata: (skip)
* @object: The GObject to set store a user data pointer
* @quark: A #GQuark, naming the user data pointer
* @data: (nullable): An opaque user data pointer
*
* This sets an opaque, named pointer on an object.
* The name is specified through a #GQuark (retrieved e.g. via
* g_quark_from_static_string()), and the pointer
* can be gotten back from the @object with g_object_get_qdata()
* until the @object is finalized.
* Setting a previously set user data pointer, overrides (frees)
* the old pointer set, using #NULL as pointer essentially
* removes the data stored.
*/
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);
}
/**
* g_object_dup_qdata: (skip)
* @object: the #GObject to store user data on
* @quark: a #GQuark, naming the user data pointer
* @dup_func: (nullable): function to dup the value
* @user_data: (nullable): passed as user_data to @dup_func
*
* This is a variant of g_object_get_qdata() which returns
* a 'duplicate' of the value. @dup_func defines the
* meaning of 'duplicate' in this context, it could e.g.
* take a reference on a ref-counted object.
*
* If the @quark is not set on the object then @dup_func
* will be called with a %NULL argument.
*
* Note that @dup_func is called while user data of @object
* is locked.
*
* This function can be useful to avoid races when multiple
* threads are using object data on the same key on the same
* object.
*
* Returns: the result of calling @dup_func on the value
* associated with @quark on @object, or %NULL if not set.
* If @dup_func is %NULL, the value is returned
* unmodified.
*
* Since: 2.34
*/
gpointer
g_object_dup_qdata (GObject *object,
GQuark quark,
GDuplicateFunc dup_func,
gpointer user_data)
{
g_return_val_if_fail (G_IS_OBJECT (object), NULL);
g_return_val_if_fail (quark > 0, NULL);
return g_datalist_id_dup_data (&object->qdata, quark, dup_func, user_data);
}
/**
* g_object_replace_qdata: (skip)
* @object: the #GObject to store user data on
* @quark: a #GQuark, naming the user data pointer
* @oldval: (nullable): the old value to compare against
* @newval: (nullable): the new value
* @destroy: (nullable): a destroy notify for the new value
* @old_destroy: (out) (optional): destroy notify for the existing value
*
* Compares the user data for the key @quark on @object with
* @oldval, and if they are the same, replaces @oldval with
* @newval.
*
* This is like a typical atomic compare-and-exchange
* operation, for user data on an object.
*
* If the previous value was replaced then ownership of the
* old value (@oldval) is passed to the caller, including
* the registered destroy notify for it (passed out in @old_destroy).
* It’s up to the caller to free this as needed, which may
* or may not include using @old_destroy as sometimes replacement
* should not destroy the object in the normal way.
*
* Returns: %TRUE if the existing value for @quark was replaced
* by @newval, %FALSE otherwise.
*
* Since: 2.34
*/
gboolean
g_object_replace_qdata (GObject *object,
GQuark quark,
gpointer oldval,
gpointer newval,
GDestroyNotify destroy,
GDestroyNotify *old_destroy)
{
g_return_val_if_fail (G_IS_OBJECT (object), FALSE);
g_return_val_if_fail (quark > 0, FALSE);
return g_datalist_id_replace_data (&object->qdata, quark,
oldval, newval, destroy,
old_destroy);
}
/**
* g_object_set_qdata_full: (skip)
* @object: The GObject to set store a user data pointer
* @quark: A #GQuark, naming the user data pointer
* @data: (nullable): An opaque user data pointer
* @destroy: (nullable): Function to invoke with @data as argument, when @data
* needs to be freed
*
* This function works like g_object_set_qdata(), but in addition,
* a void (*destroy) (gpointer) function may be specified which is
* called with @data as argument when the @object is finalized, or
* the data is being overwritten by a call to g_object_set_qdata()
* with the same @quark.
*/
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);
}
/**
* g_object_steal_qdata:
* @object: The GObject to get a stored user data pointer from
* @quark: A #GQuark, naming the user data pointer
*
* This function gets back user data pointers stored via
* g_object_set_qdata() and removes the @data from object
* without invoking its destroy() function (if any was
* set).
* Usually, calling this function is only required to update
* user data pointers with a destroy notifier, for example:
* |[<!-- language="C" -->
* void
* object_add_to_user_list (GObject *object,
* const gchar *new_string)
* {
* // the quark, naming the object data
* GQuark quark_string_list = g_quark_from_static_string ("my-string-list");
* // retrieve the old string list
* GList *list = g_object_steal_qdata (object, quark_string_list);
*
* // prepend new string
* list = g_list_prepend (list, g_strdup (new_string));
* // this changed 'list', so we need to set it again
* g_object_set_qdata_full (object, quark_string_list, list, free_string_list);
* }
* static void
* free_string_list (gpointer data)
* {
* GList *node, *list = data;
*
* for (node = list; node; node = node->next)
* g_free (node->data);
* g_list_free (list);
* }
* ]|
* Using g_object_get_qdata() in the above example, instead of
* g_object_steal_qdata() would have left the destroy function set,
* and thus the partial string list would have been freed upon
* g_object_set_qdata_full().
*
* Returns: (transfer full) (nullable): The user data pointer set, or %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);
}
/**
* g_object_get_data:
* @object: #GObject containing the associations
* @key: name of the key for that association
*
* Gets a named field from the objects table of associations (see g_object_set_data()).
*
* Returns: (transfer none) (nullable): the data if found,
* or %NULL if no such data exists.
*/
gpointer
g_object_get_data (GObject *object,
const gchar *key)
{
g_return_val_if_fail (G_IS_OBJECT (object), NULL);
g_return_val_if_fail (key != NULL, NULL);
return g_datalist_get_data (&object->qdata, key);
}
/**
* g_object_set_data:
* @object: #GObject containing the associations.
* @key: name of the key
* @data: (nullable): data to associate with that key
*
* Each object carries around a table of associations from
* strings to pointers. This function lets you set an association.
*
* If the object already had an association with that name,
* the old association will be destroyed.
*
* Internally, the @key is converted to a #GQuark using g_quark_from_string().
* This means a copy of @key is kept permanently (even after @object has been
* finalized) — so it is recommended to only use a small, bounded set of values
* for @key in your program, to avoid the #GQuark storage growing unbounded.
*/
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);
}
/**
* g_object_dup_data: (skip)
* @object: the #GObject to store user data on
* @key: a string, naming the user data pointer
* @dup_func: (nullable): function to dup the value
* @user_data: (nullable): passed as user_data to @dup_func
*
* This is a variant of g_object_get_data() which returns
* a 'duplicate' of the value. @dup_func defines the
* meaning of 'duplicate' in this context, it could e.g.
* take a reference on a ref-counted object.
*
* If the @key is not set on the object then @dup_func
* will be called with a %NULL argument.
*
* Note that @dup_func is called while user data of @object
* is locked.
*
* This function can be useful to avoid races when multiple
* threads are using object data on the same key on the same
* object.
*
* Returns: the result of calling @dup_func on the value
* associated with @key on @object, or %NULL if not set.
* If @dup_func is %NULL, the value is returned
* unmodified.
*
* Since: 2.34
*/
gpointer
g_object_dup_data (GObject *object,
const gchar *key,
GDuplicateFunc dup_func,
gpointer user_data)
{
g_return_val_if_fail (G_IS_OBJECT (object), NULL);
g_return_val_if_fail (key != NULL, NULL);
return g_datalist_id_dup_data (&object->qdata,
g_quark_from_string (key),
dup_func, user_data);
}
/**
* g_object_replace_data: (skip)
* @object: the #GObject to store user data on
* @key: a string, naming the user data pointer
* @oldval: (nullable): the old value to compare against
* @newval: (nullable): the new value
* @destroy: (nullable): a destroy notify for the new value
* @old_destroy: (out) (optional): destroy notify for the existing value
*
* Compares the user data for the key @key on @object with
* @oldval, and if they are the same, replaces @oldval with
* @newval.
*
* This is like a typical atomic compare-and-exchange
* operation, for user data on an object.
*
* If the previous value was replaced then ownership of the
* old value (@oldval) is passed to the caller, including
* the registered destroy notify for it (passed out in @old_destroy).
* It’s up to the caller to free this as needed, which may
* or may not include using @old_destroy as sometimes replacement
* should not destroy the object in the normal way.
*
* See g_object_set_data() for guidance on using a small, bounded set of values
* for @key.
*
* Returns: %TRUE if the existing value for @key was replaced
* by @newval, %FALSE otherwise.
*
* Since: 2.34
*/
gboolean
g_object_replace_data (GObject *object,
const gchar *key,
gpointer oldval,
gpointer newval,
GDestroyNotify destroy,
GDestroyNotify *old_destroy)
{
g_return_val_if_fail (G_IS_OBJECT (object), FALSE);
g_return_val_if_fail (key != NULL, FALSE);
return g_datalist_id_replace_data (&object->qdata,
g_quark_from_string (key),
oldval, newval, destroy,
old_destroy);
}
/**
* g_object_set_data_full: (skip)
* @object: #GObject containing the associations
* @key: name of the key
* @data: (nullable): data to associate with that key
* @destroy: (nullable): function to call when the association is destroyed
*
* Like g_object_set_data() except it adds notification
* for when the association is destroyed, either by setting it
* to a different value or when the object is destroyed.
*
* Note that the @destroy callback is not called if @data is %NULL.
*/
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);
}
/**
* g_object_steal_data:
* @object: #GObject containing the associations
* @key: name of the key
*
* Remove a specified datum from the object's data associations,
* without invoking the association's destroy handler.
*
* Returns: (transfer full) (nullable): the data if found, or %NULL
* if no such data exists.
*/
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)
{
g_clear_object ((GObject**) &value->data[0].v_pointer);
}
static void
g_value_object_copy_value (const GValue *src_value,
GValue *dest_value)
{
g_set_object ((GObject**) &dest_value->data[0].v_pointer,
src_value->data[0].v_pointer);
}
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;
g_return_val_if_fail (object_p != NULL, 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;
}
/**
* g_value_set_object:
* @value: a valid #GValue of %G_TYPE_OBJECT derived type
* @v_object: (type GObject.Object) (nullable): object value to be set
*
* Set the contents of a %G_TYPE_OBJECT derived #GValue to @v_object.
*
* g_value_set_object() increases the reference count of @v_object
* (the #GValue holds a reference to @v_object). If you do not wish
* to increase the reference count of the object (i.e. you wish to
* pass your current reference to the #GValue because you no longer
* need it), use g_value_take_object() instead.
*
* It is important that your #GValue holds a reference to @v_object (either its
* own, or one it has taken) to ensure that the object won't be destroyed while
* the #GValue still exists).
*/
void
g_value_set_object (GValue *value,
gpointer v_object)
{
GObject *old;
g_return_if_fail (G_VALUE_HOLDS_OBJECT (value));
if G_UNLIKELY (value->data[0].v_pointer == v_object)
return;
old = g_steal_pointer (&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 = g_object_ref (v_object);
}
g_clear_object (&old);
}
/**
* g_value_set_object_take_ownership: (skip)
* @value: a valid #GValue of %G_TYPE_OBJECT derived type
* @v_object: (nullable): object value to be set
*
* This is an internal function introduced mainly for C marshallers.
*
* Deprecated: 2.4: Use g_value_take_object() instead.
*/
void
g_value_set_object_take_ownership (GValue *value,
gpointer v_object)
{
g_value_take_object (value, v_object);
}
/**
* g_value_take_object: (skip)
* @value: a valid #GValue of %G_TYPE_OBJECT derived type
* @v_object: (nullable): object value to be set
*
* Sets the contents of a %G_TYPE_OBJECT derived #GValue to @v_object
* and takes over the ownership of the caller’s reference to @v_object;
* the caller doesn’t have to unref it any more (i.e. the reference
* count of the object is not increased).
*
* If you want the #GValue to hold its own reference to @v_object, use
* g_value_set_object() instead.
*
* Since: 2.4
*/
void
g_value_take_object (GValue *value,
gpointer v_object)
{
g_return_if_fail (G_VALUE_HOLDS_OBJECT (value));
g_clear_object ((GObject **) &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 = g_steal_pointer (&v_object);
}
}
/**
* g_value_get_object:
* @value: a valid #GValue of %G_TYPE_OBJECT derived type
*
* Get the contents of a %G_TYPE_OBJECT derived #GValue.
*
* Returns: (type GObject.Object) (transfer none) (nullable): object contents of @value
*/
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;
}
/**
* g_value_dup_object:
* @value: a valid #GValue whose type is derived from %G_TYPE_OBJECT
*
* Get the contents of a %G_TYPE_OBJECT derived #GValue, increasing
* its reference count. If the contents of the #GValue are %NULL, then
* %NULL will be returned.
*
* Returns: (type GObject.Object) (transfer full) (nullable): object content of @value,
* should be unreferenced when no longer needed.
*/
gpointer
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;
}
/**
* g_signal_connect_object: (skip)
* @instance: (type GObject.TypeInstance): the instance to connect to.
* @detailed_signal: a string of the form "signal-name::detail".
* @c_handler: the #GCallback to connect.
* @gobject: (type GObject.Object) (nullable): the object to pass as data
* to @c_handler.
* @connect_flags: a combination of #GConnectFlags.
*
* This is similar to g_signal_connect_data(), but uses a closure which
* ensures that the @gobject stays alive during the call to @c_handler
* by temporarily adding a reference count to @gobject.
*
* When the @gobject is destroyed the signal handler will be automatically
* disconnected. Note that this is not currently threadsafe (ie:
* emitting a signal while @gobject is being destroyed in another thread
* is not safe).
*
* Returns: the handler id.
*/
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;
static void
object_remove_closure (gpointer data,
GClosure *closure)
{
GObject *object = data;
CArray *carray;
guint i;
object_bit_lock (object, OPTIONAL_BIT_LOCK_CLOSURE_ARRAY);
carray = g_object_get_qdata (object, quark_closure_array);
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];
object_bit_unlock (object, OPTIONAL_BIT_LOCK_CLOSURE_ARRAY);
return;
}
object_bit_unlock (object, OPTIONAL_BIT_LOCK_CLOSURE_ARRAY);
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);
}
/**
* g_object_watch_closure:
* @object: #GObject restricting lifetime of @closure
* @closure: #GClosure to watch
*
* This function essentially limits the life time of the @closure to
* the life time of the object. That is, when the object is finalized,
* the @closure is invalidated by calling g_closure_invalidate() on
* it, in order to prevent invocations of the closure with a finalized
* (nonexisting) object. Also, g_object_ref() and g_object_unref() are
* added as marshal guards to the @closure, to ensure that an extra
* reference count is held on @object during invocation of the
* @closure. Usually, this function will be called on closures that
* use this @object as closure data.
*/
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 (g_atomic_int_get (&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);
object_bit_lock (object, OPTIONAL_BIT_LOCK_CLOSURE_ARRAY);
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);
object_bit_unlock (object, OPTIONAL_BIT_LOCK_CLOSURE_ARRAY);
}
/**
* g_closure_new_object:
* @sizeof_closure: the size of the structure to allocate, must be at least
* `sizeof (GClosure)`
* @object: a #GObject pointer to store in the @data field of the newly
* allocated #GClosure
*
* A variant of g_closure_new_simple() which stores @object in the
* @data field of the closure and calls g_object_watch_closure() on
* @object and the created closure. This function is mainly useful
* when implementing new types of closures.
*
* Returns: (transfer floating): a newly allocated #GClosure
*/
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 (g_atomic_int_get (&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;
}
/**
* g_cclosure_new_object: (skip)
* @callback_func: the function to invoke
* @object: a #GObject pointer to pass to @callback_func
*
* A variant of g_cclosure_new() which uses @object as @user_data and
* calls g_object_watch_closure() on @object and the created
* closure. This function is useful when you have a callback closely
* associated with a #GObject, and want the callback to no longer run
* after the object is is freed.
*
* Returns: (transfer floating): a new #GCClosure
*/
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 (g_atomic_int_get (&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;
}
/**
* g_cclosure_new_object_swap: (skip)
* @callback_func: the function to invoke
* @object: a #GObject pointer to pass to @callback_func
*
* A variant of g_cclosure_new_swap() which uses @object as @user_data
* and calls g_object_watch_closure() on @object and the created
* closure. This function is useful when you have a callback closely
* associated with a #GObject, and want the callback to no longer run
* after the object is is freed.
*
* Returns: (transfer floating): a new #GCClosure
*/
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 (g_atomic_int_get (&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;
}
gsize
g_object_compat_control (gsize what,
gpointer data)
{
switch (what)
{
gpointer *pp;
case 1: /* floating base type */
return (gsize) G_TYPE_INITIALLY_UNOWNED;
case 2: /* FIXME: remove this once GLib/Gtk+ break ABI again */
floating_flag_handler = (guint(*)(GObject*,gint)) data;
return 1;
case 3: /* FIXME: remove this once GLib/Gtk+ break ABI again */
pp = data;
*pp = floating_flag_handler;
return 1;
default:
return 0;
}
}
G_DEFINE_TYPE (GInitiallyUnowned, g_initially_unowned, G_TYPE_OBJECT)
static void
g_initially_unowned_init (GInitiallyUnowned *object)
{
g_object_force_floating (object);
}
static void
g_initially_unowned_class_init (GInitiallyUnownedClass *klass)
{
}
/**
* GWeakRef:
*
* A structure containing a weak reference to a #GObject.
*
* A `GWeakRef` can either be empty (i.e. point to %NULL), or point to an
* object for as long as at least one "strong" reference to that object
* exists. Before the object's #GObjectClass.dispose method is called,
* every #GWeakRef associated with becomes empty (i.e. points to %NULL).
*
* Like #GValue, #GWeakRef can be statically allocated, stack- or
* heap-allocated, or embedded in larger structures.
*
* Unlike g_object_weak_ref() and g_object_add_weak_pointer(), this weak
* reference is thread-safe: converting a weak pointer to a reference is
* atomic with respect to invalidation of weak pointers to destroyed
* objects.
*
* If the object's #GObjectClass.dispose method results in additional
* references to the object being held (‘re-referencing’), any #GWeakRefs taken
* before it was disposed will continue to point to %NULL. Any #GWeakRefs taken
* during disposal and after re-referencing, or after disposal has returned due
* to the re-referencing, will continue to point to the object until its refcount
* goes back to zero, at which point they too will be invalidated.
*
* It is invalid to take a #GWeakRef on an object during #GObjectClass.dispose
* without first having or creating a strong reference to the object.
*/
#define WEAK_REF_LOCK_BIT 0
static GObject *
_weak_ref_clean_pointer (gpointer ptr)
{
/* Drop the lockbit WEAK_REF_LOCK_BIT from @ptr (if set). */
return g_pointer_bit_lock_mask_ptr (ptr, WEAK_REF_LOCK_BIT, FALSE, 0, NULL);
}
static void
_weak_ref_lock (GWeakRef *weak_ref, GObject **out_object)
{
/* Note that while holding a _weak_ref_lock() on the @weak_ref, we MUST not acquire a
* weak_ref_data_lock() on the @wrdata. The other way around! */
if (out_object)
{
guintptr ptr;
g_pointer_bit_lock_and_get (&weak_ref->priv.p, WEAK_REF_LOCK_BIT, &ptr);
*out_object = _weak_ref_clean_pointer ((gpointer) ptr);
}
else
g_pointer_bit_lock (&weak_ref->priv.p, WEAK_REF_LOCK_BIT);
}
static void
_weak_ref_unlock (GWeakRef *weak_ref)
{
g_pointer_bit_unlock (&weak_ref->priv.p, WEAK_REF_LOCK_BIT);
}
static void
_weak_ref_unlock_and_set (GWeakRef *weak_ref, GObject *object)
{
g_pointer_bit_unlock_and_set (&weak_ref->priv.p, WEAK_REF_LOCK_BIT, object, 0);
}
static void
weak_ref_data_clear_list (WeakRefData *wrdata, GObject *object)
{
while (wrdata->len > 0u)
{
GWeakRef *weak_ref;
gpointer ptr;
/* pass "allow_shrink=FALSE", so we don't reallocate needlessly. We
* anyway are about to clear the entire list. */
weak_ref = weak_ref_data_list_remove (wrdata, wrdata->len - 1u, FALSE);
/* Fast-path. Most likely @weak_ref is currently not locked, so we can
* just atomically set the pointer to NULL. */
ptr = g_atomic_pointer_get (&weak_ref->priv.p);
#if G_ENABLE_DEBUG
g_assert (G_IS_OBJECT (_weak_ref_clean_pointer (ptr)));
g_assert (!object || object == _weak_ref_clean_pointer (ptr));
#endif
if (G_LIKELY (ptr == _weak_ref_clean_pointer (ptr)))
{
/* The pointer is unlocked. Try an atomic compare-and-exchange... */
if (g_atomic_pointer_compare_and_exchange (&weak_ref->priv.p, ptr, NULL))
{
/* Done. Go to the next. */
continue;
}
}
/* The @weak_ref is locked. Acquire the lock to set the pointer to NULL. */
_weak_ref_lock (weak_ref, NULL);
_weak_ref_unlock_and_set (weak_ref, NULL);
}
}
static void
_weak_ref_set (GWeakRef *weak_ref,
GObject *new_object,
gboolean called_by_init)
{
WeakRefData *old_wrdata;
WeakRefData *new_wrdata;
GObject *old_object;
new_wrdata = weak_ref_data_get_or_create (new_object);
#if G_ENABLE_DEBUG
g_assert (!new_object || object_get_optional_flags (new_object) & OPTIONAL_FLAG_EVER_HAD_WEAK_REF);
#endif
if (called_by_init)
{
/* The caller is g_weak_ref_init(). We know that the weak_ref should be
* NULL. We thus set @old_wrdata to NULL without checking.
*
* Also important, the caller ensured that @new_object is not NULL. So we
* are expected to set @weak_ref from NULL to a non-NULL @new_object. */
old_wrdata = NULL;
#if G_ENABLE_DEBUG
g_assert (new_object);
#endif
}
else
{
/* We must get a wrdata object @old_wrdata for the current @old_object. */
_weak_ref_lock (weak_ref, &old_object);
if (old_object == new_object)
{
/* Already set. We are done. */
_weak_ref_unlock (weak_ref);
return;
}
old_wrdata = old_object
? weak_ref_data_ref (weak_ref_data_get (old_object))
: NULL;
_weak_ref_unlock (weak_ref);
}
/* We need a lock on @old_wrdata, @new_wrdata and @weak_ref. We need to take
* these locks in a certain order to avoid deadlock. We sort them by pointer
* value.
*
* Note that @old_wrdata or @new_wrdata may be NULL, which is handled
* correctly.
*
* Note that @old_wrdata and @new_wrdata are never identical at this point.
*/
if (new_wrdata && old_wrdata && (((guintptr) (gpointer) old_wrdata) < ((guintptr) ((gpointer) new_wrdata))))
{
weak_ref_data_lock (old_wrdata);
weak_ref_data_lock (new_wrdata);
}
else
{
weak_ref_data_lock (new_wrdata);
weak_ref_data_lock (old_wrdata);
}
_weak_ref_lock (weak_ref, &old_object);
if (!weak_ref_data_has (old_object, old_wrdata, NULL))
{
/* A race. @old_object no longer has the expected @old_wrdata after
* getting all the locks. */
if (old_object)
{
/* We lost the race and find a different object set. It's fine, our
* action was lost in the race and we are done. No need to retry. */
weak_ref_data_unlock (old_wrdata);
weak_ref_data_unlock (new_wrdata);
_weak_ref_unlock (weak_ref);
weak_ref_data_unref (old_wrdata);
return;
}
/* @old_object is NULL after a race. We didn't expect that, but it's
* fine. Proceed to set @new_object... */
}
if (old_object)
{
gint32 idx;
idx = weak_ref_data_list_find (old_wrdata, weak_ref);
if (idx < 0)
g_critical ("unexpected missing GWeakRef data");
else
weak_ref_data_list_remove (old_wrdata, idx, TRUE);
}
weak_ref_data_unlock (old_wrdata);
if (new_object)
{
#if G_ENABLE_DEBUG
g_assert (new_wrdata != NULL);
g_assert (weak_ref_data_list_find (new_wrdata, weak_ref) < 0);
#endif
if (g_atomic_int_get (&new_object->ref_count) < 1)
{
g_critical ("calling g_weak_ref_set() with already destroyed object");
new_object = NULL;
}
else
{
if (!weak_ref_data_list_add (new_wrdata, weak_ref))
{
g_critical ("Too many GWeakRef registered");
new_object = NULL;
}
}
}
_weak_ref_unlock_and_set (weak_ref, new_object);
weak_ref_data_unlock (new_wrdata);
weak_ref_data_unref (old_wrdata);
}
/**
* g_weak_ref_init: (skip)
* @weak_ref: (inout): uninitialized or empty location for a weak
* reference
* @object: (type GObject.Object) (nullable): a #GObject or %NULL
*
* Initialise a non-statically-allocated #GWeakRef.
*
* This function also calls g_weak_ref_set() with @object on the
* freshly-initialised weak reference.
*
* This function should always be matched with a call to
* g_weak_ref_clear(). It is not necessary to use this function for a
* #GWeakRef in static storage because it will already be
* properly initialised. Just use g_weak_ref_set() directly.
*
* Since: 2.32
*/
void
g_weak_ref_init (GWeakRef *weak_ref,
gpointer object)
{
g_return_if_fail (weak_ref);
g_return_if_fail (object == NULL || G_IS_OBJECT (object));
g_atomic_pointer_set (&weak_ref->priv.p, NULL);
if (object)
{
/* We give a hint that the weak_ref is currently NULL. Unlike
* g_weak_ref_set(), we then don't need the extra lock just to
* find out that we have no object. */
_weak_ref_set (weak_ref, object, TRUE);
}
}
/**
* g_weak_ref_clear: (skip)
* @weak_ref: (inout): location of a weak reference, which
* may be empty
*
* Frees resources associated with a non-statically-allocated #GWeakRef.
* After this call, the #GWeakRef is left in an undefined state.
*
* You should only call this on a #GWeakRef that previously had
* g_weak_ref_init() called on it.
*
* Since: 2.32
*/
void
g_weak_ref_clear (GWeakRef *weak_ref)
{
g_weak_ref_set (weak_ref, NULL);
/* be unkind */
weak_ref->priv.p = (void *) 0xccccccccu;
}
/**
* g_weak_ref_get: (skip)
* @weak_ref: (inout): location of a weak reference to a #GObject
*
* If @weak_ref is not empty, atomically acquire a strong
* reference to the object it points to, and return that reference.
*
* This function is needed because of the potential race between taking
* the pointer value and g_object_ref() on it, if the object was losing
* its last reference at the same time in a different thread.
*
* The caller should release the resulting reference in the usual way,
* by using g_object_unref().
*
* Returns: (transfer full) (type GObject.Object): the object pointed to
* by @weak_ref, or %NULL if it was empty
*
* Since: 2.32
*/
gpointer
g_weak_ref_get (GWeakRef *weak_ref)
{
WeakRefData *wrdata;
WeakRefData *new_wrdata;
GToggleNotify toggle_notify = NULL;
gpointer toggle_data = NULL;
GObject *object;
g_return_val_if_fail (weak_ref, NULL);
/* We cannot take the strong reference on @object yet. Otherwise,
* _object_unref_clear_weak_locations() might have just taken the lock on
* @wrdata, see that the ref-count is 1 and plan to proceed clearing weak
* locations. If we then take a strong reference here, the object becomes
* alive and well, but _object_unref_clear_weak_locations() would proceed and
* clear the @weak_ref.
*
* We avoid that, by can only taking the strong reference when having a lock
* on @wrdata, so we are in sync with _object_unref_clear_weak_locations().
*
* But first we must get a reference to the @wrdata.
*/
_weak_ref_lock (weak_ref, &object);
wrdata = object
? weak_ref_data_ref (weak_ref_data_get (object))
: NULL;
_weak_ref_unlock (weak_ref);
if (!wrdata)
{
/* There is no @wrdata and no object. We are done. */
return NULL;
}
retry:
/* Now proceed to get the strong reference. This time with acquiring a lock
* on the per-object @wrdata and on @weak_ref.
*
* As the order in which locks are taken is important, we previously had to
* get a _weak_ref_lock(), to obtain the @wrdata. Now we have to lock on the
* @wrdata first, and the @weak_ref again. */
weak_ref_data_lock (wrdata);
_weak_ref_lock (weak_ref, &object);
if (!object)
{
/* Object is gone in the meantime. That is fine. */
new_wrdata = NULL;
}
else
{
/* Check that @object still refers to the same object as before. We do
* that by comparing the @wrdata object. A GObject keeps its (unique!)
* wrdata instance until the end, and since @wrdata is still alive,
* @object is the same as before, if-and-only-if its @wrdata is the same.
*/
if (weak_ref_data_has (object, wrdata, &new_wrdata))
{
/* We are (still) good. Take a strong ref while holding the necessary locks. */
object = object_ref (object, &toggle_notify, &toggle_data);
}
else
{
/* The @object changed and has no longer the same @wrdata. In this
* case, we need to start over.
*
* Note that @new_wrdata references the wrdata of the now current
* @object. We will use that during the retry. */
}
}
_weak_ref_unlock (weak_ref);
weak_ref_data_unlock (wrdata);
weak_ref_data_unref (wrdata);
if (new_wrdata)
{
/* There was a race. The object changed. Retry, with @new_wrdata. */
wrdata = new_wrdata;
goto retry;
}
if (toggle_notify)
toggle_notify (toggle_data, object, FALSE);
return object;
}
/**
* g_weak_ref_set: (skip)
* @weak_ref: location for a weak reference
* @object: (type GObject.Object) (nullable): a #GObject or %NULL
*
* Change the object to which @weak_ref points, or set it to
* %NULL.
*
* You must own a strong reference on @object while calling this
* function.
*
* Since: 2.32
*/
void
g_weak_ref_set (GWeakRef *weak_ref,
gpointer object)
{
g_return_if_fail (weak_ref != NULL);
g_return_if_fail (object == NULL || G_IS_OBJECT (object));
_weak_ref_set (weak_ref, object, FALSE);
}