gstreamer/gst/gstminiobject.h
Wim Taymans ee235a6b07 miniobject: avoid race in bufferpool release
Avoid playing with the refcount to decide when a buffer has been recycled by the
dispose function. The problem is that we then temporarily can have a buffer with
a refcount > 1 being acquired from the pool, which is not writable. Instead use
a simple boolean return value from the dispose function to inform the called
that the object was recycled or not.
2011-07-25 12:53:10 +02:00

224 lines
6.9 KiB
C

/* GStreamer
* Copyright (C) 2005 David Schleef <ds@schleef.org>
*
* gstminiobject.h: Header for GstMiniObject
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#ifndef __GST_MINI_OBJECT_H__
#define __GST_MINI_OBJECT_H__
#include <gst/gstconfig.h>
#include <glib-object.h>
G_BEGIN_DECLS
#define GST_IS_MINI_OBJECT_TYPE(obj,type) ((obj) && GST_MINI_OBJECT_TYPE(obj) == (type))
#define GST_MINI_OBJECT_CAST(obj) ((GstMiniObject*)(obj))
#define GST_MINI_OBJECT_CONST_CAST(obj) ((const GstMiniObject*)(obj))
#define GST_MINI_OBJECT(obj) (GST_MINI_OBJECT_CAST(obj))
typedef struct _GstMiniObject GstMiniObject;
/**
* GstMiniObjectCopyFunction:
* @obj: MiniObject to copy
*
* Function prototype for methods to create copies of instances.
*
* Returns: reference to cloned instance.
*/
typedef GstMiniObject * (*GstMiniObjectCopyFunction) (const GstMiniObject *obj);
/**
* GstMiniObjectDisposeFunction:
* @obj: MiniObject to dispose
*
* Function prototype for when a miniobject has lost its last refcount.
* Implementation of the mini object are allowed to revive the
* passed object by doing a gst_mini_object_ref(). If the object is not
* revived after the dispose function, the function should return %TRUE
* and the memory associated with the object is freed.
*
* Returns: %TRUE if the object should be cleaned up.
*/
typedef gboolean (*GstMiniObjectDisposeFunction) (GstMiniObject *obj);
/**
* GstMiniObjectFreeFunction:
* @obj: MiniObject to free
*
* Virtual function prototype for methods to free ressources used by
* mini-objects.
*/
typedef void (*GstMiniObjectFreeFunction) (GstMiniObject *obj);
/**
* GstMiniObjectWeakNotify:
* @data: data that was provided when the weak reference was established
* @where_the_mini_object_was: the mini object being finalized
*
* A #GstMiniObjectWeakNotify function can be added to a mini object as a
* callback that gets triggered when the mini object is finalized. Since the
* mini object is already being finalized when the #GstMiniObjectWeakNotify is
* called, there's not much you could do with the object, apart from e.g. using
* its adress as hash-index or the like.
*
* Since: 0.10.35
*/
typedef void (*GstMiniObjectWeakNotify) (gpointer data,
GstMiniObject * where_the_mini_object_was);
/**
* GST_MINI_OBJECT_FLAGS:
* @obj: MiniObject to return flags for.
*
* This macro returns the entire set of flags for the mini-object.
*/
#define GST_MINI_OBJECT_TYPE(obj) (GST_MINI_OBJECT_CAST(obj)->type)
/**
* GST_MINI_OBJECT_FLAGS:
* @obj: MiniObject to return flags for.
*
* This macro returns the entire set of flags for the mini-object.
*/
#define GST_MINI_OBJECT_FLAGS(obj) (GST_MINI_OBJECT_CAST(obj)->flags)
/**
* GST_MINI_OBJECT_FLAG_IS_SET:
* @obj: MiniObject to check for flags.
* @flag: Flag to check for
*
* This macro checks to see if the given flag is set.
*/
#define GST_MINI_OBJECT_FLAG_IS_SET(obj,flag) !!(GST_MINI_OBJECT_FLAGS (obj) & (flag))
/**
* GST_MINI_OBJECT_FLAG_SET:
* @obj: MiniObject to set flag in.
* @flag: Flag to set, can by any number of bits in guint32.
*
* This macro sets the given bits.
*/
#define GST_MINI_OBJECT_FLAG_SET(obj,flag) (GST_MINI_OBJECT_FLAGS (obj) |= (flag))
/**
* GST_MINI_OBJECT_FLAG_UNSET:
* @obj: MiniObject to unset flag in.
* @flag: Flag to set, must be a single bit in guint32.
*
* This macro usets the given bits.
*/
#define GST_MINI_OBJECT_FLAG_UNSET(obj,flag) (GST_MINI_OBJECT_FLAGS (obj) &= ~(flag))
/**
* GstMiniObjectFlags:
* @GST_MINI_OBJECT_FLAG_LAST: first flag that can be used by subclasses.
*
* Flags for the mini object
*/
typedef enum
{
/* padding */
GST_MINI_OBJECT_FLAG_LAST = (1<<4)
} GstMiniObjectFlags;
/**
* GST_MINI_OBJECT_REFCOUNT:
* @obj: a #GstMiniObject
*
* Get access to the reference count field of the mini-object.
*/
#define GST_MINI_OBJECT_REFCOUNT(obj) ((GST_MINI_OBJECT_CAST(obj))->refcount)
/**
* GST_MINI_OBJECT_REFCOUNT_VALUE:
* @obj: a #GstMiniObject
*
* Get the reference count value of the mini-object.
*/
#define GST_MINI_OBJECT_REFCOUNT_VALUE(obj) (g_atomic_int_get (&(GST_MINI_OBJECT_CAST(obj))->refcount))
/**
* GST_MINI_OBJECT_SIZE:
* @obj: a #GstMiniObject
*
* Get the allocated size of @obj.
*/
#define GST_MINI_OBJECT_SIZE(obj) ((GST_MINI_OBJECT_CAST(obj))->size)
/**
* GstMiniObject:
* @refcount: atomic refcount
* @flags: extra flags.
* @copy: a copy function
* @dispose: a dispose function
* @free: the free function
*
* Base class for refcounted lightweight objects.
* Ref Func: gst_mini_object_ref
* Unref Func: gst_mini_object_unref
* Set Value Func: g_value_set_boxed
* Get Value Func: g_value_get_boxed
*/
struct _GstMiniObject {
GType type;
/*< public >*/ /* with COW */
gint refcount;
guint flags;
gsize size;
GstMiniObjectCopyFunction copy;
GstMiniObjectDisposeFunction dispose;
GstMiniObjectFreeFunction free;
/* < private > */
/* Used to keep track of weak ref notifies */
guint n_weak_refs;
struct
{
GstMiniObjectWeakNotify notify;
gpointer data;
} *weak_refs;
};
GType gst_mini_object_register (const gchar *name);
void gst_mini_object_init (GstMiniObject *mini_object,
GType type, gsize size);
GstMiniObject * gst_mini_object_copy (const GstMiniObject *mini_object);
gboolean gst_mini_object_is_writable (const GstMiniObject *mini_object);
GstMiniObject * gst_mini_object_make_writable (GstMiniObject *mini_object);
/* refcounting */
GstMiniObject * gst_mini_object_ref (GstMiniObject *mini_object);
void gst_mini_object_unref (GstMiniObject *mini_object);
void gst_mini_object_weak_ref (GstMiniObject *object,
GstMiniObjectWeakNotify notify,
gpointer data);
void gst_mini_object_weak_unref (GstMiniObject *object,
GstMiniObjectWeakNotify notify,
gpointer data);
gboolean gst_mini_object_replace (GstMiniObject **olddata, GstMiniObject *newdata);
gboolean gst_mini_object_take (GstMiniObject **olddata, GstMiniObject *newdata);
GstMiniObject * gst_mini_object_steal (GstMiniObject **olddata);
G_END_DECLS
#endif