2 * Copyright (C) 2010 Wim Taymans <wim.taymans@gmail.com>
4 * gstbufferpool.c: GstBufferPool baseclass
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Library General Public License for more details.
16 * You should have received a copy of the GNU Library General Public
17 * License along with this library; if not, write to the
18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 * Boston, MA 02111-1307, USA.
23 * SECTION:gstbufferpool
24 * @short_description: Pool for buffers
25 * @see_also: #GstBuffer
29 #include "gst_private.h"
35 #include <sys/types.h>
40 #include "gstbufferpool.h"
42 GST_DEBUG_CATEGORY_STATIC (gst_buffer_pool_debug);
43 #define GST_CAT_DEFAULT gst_buffer_pool_debug
45 #define GST_BUFFER_POOL_GET_PRIVATE(obj) \
46 (G_TYPE_INSTANCE_GET_PRIVATE ((obj), GST_TYPE_BUFFER_POOL, GstBufferPoolPrivate))
48 #define GST_BUFFER_POOL_LOCK(pool) (g_static_rec_mutex_lock(&pool->priv->rec_lock))
49 #define GST_BUFFER_POOL_UNLOCK(pool) (g_static_rec_mutex_unlock(&pool->priv->rec_lock))
51 struct _GstBufferPoolPrivate
53 GStaticRecMutex rec_lock;
68 static void gst_buffer_pool_finalize (GObject * object);
70 G_DEFINE_TYPE (GstBufferPool, gst_buffer_pool, GST_TYPE_OBJECT);
72 static gboolean default_start (GstBufferPool * pool);
73 static gboolean default_stop (GstBufferPool * pool);
74 static gboolean default_set_config (GstBufferPool * pool,
75 GstStructure * config);
76 static GstFlowReturn default_alloc_buffer (GstBufferPool * pool,
77 GstBuffer ** buffer, GstBufferPoolParams * params);
78 static GstFlowReturn default_acquire_buffer (GstBufferPool * pool,
79 GstBuffer ** buffer, GstBufferPoolParams * params);
80 static void default_free_buffer (GstBufferPool * pool, GstBuffer * buffer);
81 static void default_release_buffer (GstBufferPool * pool, GstBuffer * buffer);
84 gst_buffer_pool_class_init (GstBufferPoolClass * klass)
86 GObjectClass *gobject_class = (GObjectClass *) klass;
88 g_type_class_add_private (klass, sizeof (GstBufferPoolPrivate));
90 gobject_class->finalize = gst_buffer_pool_finalize;
92 klass->start = default_start;
93 klass->stop = default_stop;
94 klass->set_config = default_set_config;
95 klass->acquire_buffer = default_acquire_buffer;
96 klass->alloc_buffer = default_alloc_buffer;
97 klass->release_buffer = default_release_buffer;
98 klass->free_buffer = default_free_buffer;
100 GST_DEBUG_CATEGORY_INIT (gst_buffer_pool_debug, "bufferpool", 0,
105 gst_buffer_pool_init (GstBufferPool * pool)
107 pool->priv = GST_BUFFER_POOL_GET_PRIVATE (pool);
109 g_static_rec_mutex_init (&pool->priv->rec_lock);
111 pool->poll = gst_poll_new_timer ();
112 pool->queue = gst_atomic_queue_new (10);
113 pool->flushing = TRUE;
114 pool->active = FALSE;
115 pool->configured = FALSE;
116 pool->started = FALSE;
117 pool->config = gst_structure_id_empty_new (GST_QUARK (BUFFER_POOL_CONFIG));
118 gst_buffer_pool_config_set (pool->config, NULL, 0, 0, 0, 0, 0, 1);
120 GST_DEBUG_OBJECT (pool, "created");
124 gst_buffer_pool_finalize (GObject * object)
128 pool = GST_BUFFER_POOL_CAST (object);
130 GST_DEBUG_OBJECT (pool, "finalize");
132 gst_buffer_pool_set_active (pool, FALSE);
133 gst_atomic_queue_unref (pool->queue);
134 gst_poll_free (pool->poll);
135 gst_structure_free (pool->config);
136 g_static_rec_mutex_free (&pool->priv->rec_lock);
138 G_OBJECT_CLASS (gst_buffer_pool_parent_class)->finalize (object);
142 * gst_buffer_pool_new:
144 * Creates a new #GstBufferPool instance.
146 * Returns: a new #GstBufferPool instance
149 gst_buffer_pool_new (void)
151 GstBufferPool *result;
153 result = g_object_newv (GST_TYPE_BUFFER_POOL, 0, NULL);
154 GST_DEBUG_OBJECT (result, "created new buffer pool");
160 default_alloc_buffer (GstBufferPool * pool, GstBuffer ** buffer,
161 GstBufferPoolParams * params)
164 GstBufferPoolPrivate *priv = pool->priv;
166 *buffer = gst_buffer_new ();
168 align = priv->align - 1;
169 size = priv->prefix + priv->postfix + priv->size + align;
173 memptr = g_malloc (size);
174 GST_BUFFER_MALLOCDATA (*buffer) = memptr;
175 memptr = (guint8 *) ((guintptr) (memptr + align) & ~align);
176 GST_BUFFER_DATA (*buffer) = memptr + priv->prefix;
177 GST_BUFFER_SIZE (*buffer) = priv->size;
183 /* the default implementation for preallocating the buffers
186 default_start (GstBufferPool * pool)
189 GstBufferPoolPrivate *priv = pool->priv;
190 GstBufferPoolClass *pclass;
192 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
194 /* no alloc function, error */
195 if (G_UNLIKELY (pclass->alloc_buffer == NULL))
198 /* we need to prealloc buffers */
199 for (i = 0; i < priv->min_buffers; i++) {
202 if (pclass->alloc_buffer (pool, &buffer, NULL) != GST_FLOW_OK)
205 GST_LOG_OBJECT (pool, "prealloced buffer %d: %p", i, buffer);
206 /* store in the queue */
207 gst_atomic_queue_push (pool->queue, buffer);
208 gst_poll_write_control (pool->poll);
215 GST_WARNING_OBJECT (pool, "no alloc function");
220 GST_WARNING_OBJECT (pool, "alloc function failed");
225 /* must be called with the lock */
227 do_start (GstBufferPool * pool)
229 if (!pool->started) {
230 GstBufferPoolClass *pclass;
232 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
234 GST_LOG_OBJECT (pool, "starting");
235 /* start the pool, subclasses should allocate buffers and put them
237 if (G_LIKELY (pclass->start)) {
238 if (!pclass->start (pool))
241 pool->started = TRUE;
248 default_free_buffer (GstBufferPool * pool, GstBuffer * buffer)
250 gst_buffer_unref (buffer);
253 /* must be called with the lock */
255 default_stop (GstBufferPool * pool)
258 GstBufferPoolClass *pclass;
260 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
263 while ((buffer = gst_atomic_queue_pop (pool->queue))) {
264 gst_poll_read_control (pool->poll);
266 if (G_LIKELY (pclass->free_buffer))
267 pclass->free_buffer (pool, buffer);
272 /* must be called with the lock */
274 do_stop (GstBufferPool * pool)
277 GstBufferPoolClass *pclass;
279 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
281 GST_LOG_OBJECT (pool, "stopping");
282 if (G_LIKELY (pclass->stop)) {
283 if (!pclass->stop (pool))
286 pool->started = FALSE;
292 * gst_buffer_pool_set_active:
293 * @pool: a #GstBufferPool
294 * @active: the new active state
296 * Control the active state of @pool. When the pool is active, new calls to
297 * gst_buffer_pool_acquire_buffer() will return with GST_FLOW_WRONG_STATE.
299 * Returns: %FALSE when the pool was not configured or when preallocation of the
303 gst_buffer_pool_set_active (GstBufferPool * pool, gboolean active)
305 GstBufferPoolClass *pclass;
308 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), FALSE);
310 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
312 GST_LOG_OBJECT (pool, "active %d", active);
314 GST_BUFFER_POOL_LOCK (pool);
315 /* just return if we are already in the right state */
316 if (pool->active == active)
319 /* we need to be configured */
320 if (!pool->configured)
324 if (!do_start (pool))
327 /* unset the flushing state now */
328 gst_poll_read_control (pool->poll);
329 g_atomic_int_set (&pool->flushing, FALSE);
331 /* set to flushing first */
332 g_atomic_int_set (&pool->flushing, TRUE);
333 gst_poll_write_control (pool->poll);
335 /* when all buffers are in the pool, free them. Else they will be
336 * freed when they are released */
337 if (g_atomic_int_get (&pool->outstanding) == 0) {
342 pool->active = active;
343 GST_BUFFER_POOL_UNLOCK (pool);
349 GST_DEBUG_OBJECT (pool, "pool was in the right state");
350 GST_BUFFER_POOL_UNLOCK (pool);
355 GST_ERROR_OBJECT (pool, "pool was not configured");
356 GST_BUFFER_POOL_UNLOCK (pool);
361 GST_ERROR_OBJECT (pool, "start failed");
362 GST_BUFFER_POOL_UNLOCK (pool);
367 GST_WARNING_OBJECT (pool, "stop failed");
368 GST_BUFFER_POOL_UNLOCK (pool);
374 default_set_config (GstBufferPool * pool, GstStructure * config)
376 GstBufferPoolPrivate *priv = pool->priv;
378 guint size, min_buffers, max_buffers;
379 guint prefix, postfix, align;
381 /* parse the config and keep around */
382 if (!gst_buffer_pool_config_get (config, &caps, &size, &min_buffers,
383 &max_buffers, &prefix, &postfix, &align))
387 priv->min_buffers = min_buffers;
388 priv->max_buffers = max_buffers;
389 priv->prefix = prefix;
390 priv->postfix = postfix;
397 GST_WARNING_OBJECT (pool, "invalid config");
403 * gst_buffer_pool_set_config:
404 * @pool: a #GstBufferPool
405 * @config: a #GstStructure
407 * Set the configuration of the pool. The pool must be inactive and all buffers
408 * allocated form this pool must be returned or else this function will do
409 * nothing and return FALSE.
411 * @condfig is a #GstStructure that contains the configuration parameters for
412 * the pool. A default and mandatory set of parameters can be configured with
413 * gst_buffer_pool_config_set(). This function takes ownership of @config.
415 * Returns: TRUE when the configuration could be set.
418 gst_buffer_pool_set_config (GstBufferPool * pool, GstStructure * config)
421 GstBufferPoolClass *pclass;
423 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), FALSE);
424 g_return_val_if_fail (config != NULL, FALSE);
426 GST_BUFFER_POOL_LOCK (pool);
427 /* can't change the settings when active */
431 /* we can't change when outstanding buffers */
432 if (g_atomic_int_get (&pool->outstanding) != 0)
433 goto have_outstanding;
435 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
437 /* set the new config */
438 if (G_LIKELY (pclass->set_config))
439 result = pclass->set_config (pool, config);
445 gst_structure_free (pool->config);
446 pool->config = config;
448 /* now we are configured */
449 pool->configured = TRUE;
451 GST_BUFFER_POOL_UNLOCK (pool);
458 GST_WARNING_OBJECT (pool, "can't change config, we are active");
459 GST_BUFFER_POOL_UNLOCK (pool);
464 GST_WARNING_OBJECT (pool, "can't change config, have outstanding buffers");
465 GST_BUFFER_POOL_UNLOCK (pool);
471 * gst_buffer_pool_get_config:
472 * @pool: a #GstBufferPool
474 * Get a copy of the current configuration of the pool. This configuration
475 * can either be modified and used for the gst_buffer_pool_set_config() call
476 * or it must be freed after usage.
478 * Returns: a copy of the current configuration of @pool. use
479 * gst_structure_free() after usage or gst_buffer_pool_set_config().
482 gst_buffer_pool_get_config (GstBufferPool * pool)
484 GstStructure *result;
486 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), NULL);
488 GST_BUFFER_POOL_UNLOCK (pool);
489 result = gst_structure_copy (pool->config);
490 GST_BUFFER_POOL_UNLOCK (pool);
496 * gst_buffer_pool_config_set:
497 * @pool: a #GstBufferPool
498 * @size: the size of each buffer, not including pre and post fix
499 * @min_buffers: the minimum amount of buffers to allocate.
500 * @max_buffers: the maximum amount of buffers to allocate or 0 for unlimited.
501 * @prefix: prefix each buffer with this many bytes
502 * @postfix: postfix each buffer with this many bytes
503 * @align: alignment of the buffer data.
505 * Configure @config with the given parameters.
508 gst_buffer_pool_config_set (GstStructure * config, const GstCaps * caps,
509 guint size, guint min_buffers, guint max_buffers, guint prefix,
510 guint postfix, guint align)
512 g_return_if_fail (config != NULL);
514 gst_structure_id_set (config,
515 GST_QUARK (CAPS), GST_TYPE_CAPS, caps,
516 GST_QUARK (SIZE), G_TYPE_UINT, size,
517 GST_QUARK (MIN_BUFFERS), G_TYPE_UINT, min_buffers,
518 GST_QUARK (MAX_BUFFERS), G_TYPE_UINT, max_buffers,
519 GST_QUARK (PREFIX), G_TYPE_UINT, prefix,
520 GST_QUARK (POSTFIX), G_TYPE_UINT, postfix,
521 GST_QUARK (ALIGN), G_TYPE_UINT, align, NULL);
525 * gst_buffer_pool_config_get:
526 * @pool: a #GstBufferPool
527 * @size: the size of each buffer, not including pre and post fix
528 * @min_buffers: the minimum amount of buffers to allocate.
529 * @max_buffers: the maximum amount of buffers to allocate or 0 for unlimited.
530 * @prefix: prefix each buffer with this many bytes
531 * @postfix: postfix each buffer with this many bytes
532 * @align: alignment of the buffer data.
534 * Get the configuration values from @config.
537 gst_buffer_pool_config_get (GstStructure * config, const GstCaps ** caps,
538 guint * size, guint * min_buffers, guint * max_buffers, guint * prefix,
539 guint * postfix, guint * align)
541 g_return_val_if_fail (config != NULL, FALSE);
543 return gst_structure_id_get (config,
544 GST_QUARK (CAPS), GST_TYPE_CAPS, caps,
545 GST_QUARK (SIZE), G_TYPE_UINT, size,
546 GST_QUARK (MIN_BUFFERS), G_TYPE_UINT, min_buffers,
547 GST_QUARK (MAX_BUFFERS), G_TYPE_UINT, max_buffers,
548 GST_QUARK (PREFIX), G_TYPE_UINT, prefix,
549 GST_QUARK (POSTFIX), G_TYPE_UINT, postfix,
550 GST_QUARK (ALIGN), G_TYPE_UINT, align, NULL);
554 default_acquire_buffer (GstBufferPool * pool, GstBuffer ** buffer,
555 GstBufferPoolParams * params)
557 GstFlowReturn result;
558 GstBufferPoolClass *pclass;
559 GstBufferPoolPrivate *priv = pool->priv;
561 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
564 if (G_UNLIKELY (g_atomic_int_get (&pool->flushing)))
565 return GST_FLOW_WRONG_STATE;
567 /* try to get a buffer from the queue */
568 *buffer = gst_atomic_queue_pop (pool->queue);
569 if (G_LIKELY (*buffer)) {
570 gst_poll_read_control (pool->poll);
571 result = GST_FLOW_OK;
576 if (priv->max_buffers == 0) {
577 /* no max_buffers, we allocate some more */
578 if (G_LIKELY (pclass->alloc_buffer)) {
579 result = pclass->alloc_buffer (pool, buffer, params);
581 result = GST_FLOW_NOT_SUPPORTED;
585 /* check if we need to wait */
586 if (params && !(params->flags & GST_BUFFER_POOL_FLAG_WAIT)) {
587 result = GST_FLOW_UNEXPECTED;
592 gst_poll_wait (pool->poll, GST_CLOCK_TIME_NONE);
599 dec_outstanding (GstBufferPool * pool)
601 if (g_atomic_int_dec_and_test (&pool->outstanding)) {
602 /* all buffers are returned to the pool, see if we need to free them */
603 if (g_atomic_int_get (&pool->flushing)) {
604 /* take the lock so that set_active is not run concurrently */
605 GST_BUFFER_POOL_LOCK (pool);
606 /* recheck the flushing state in the lock, the pool could have been
607 * set to active again */
608 if (g_atomic_int_get (&pool->flushing))
611 GST_BUFFER_POOL_UNLOCK (pool);
617 * gst_buffer_pool_acquire_buffer:
618 * @pool: a #GstBufferPool
619 * @buffer: a location for a #GstBuffer
620 * @params: parameters.
622 * Acquire a buffer from @pool. @buffer should point to a memory location that
623 * can hold a pointer to the new buffer.
625 * @params can be NULL or contain optional parameters to influence the allocation.
627 * Returns: a #GstFlowReturn such as GST_FLOW_WRONG_STATE when the pool is
631 gst_buffer_pool_acquire_buffer (GstBufferPool * pool, GstBuffer ** buffer,
632 GstBufferPoolParams * params)
634 GstBufferPoolClass *pclass;
635 GstFlowReturn result;
637 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), GST_FLOW_ERROR);
638 g_return_val_if_fail (buffer != NULL, GST_FLOW_ERROR);
640 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
642 /* assume we'll have one more outstanding buffer we need to do that so
643 * that concurrent set_active doesn't clear the buffers */
644 g_atomic_int_inc (&pool->outstanding);
646 if (G_LIKELY (pclass->acquire_buffer))
647 result = pclass->acquire_buffer (pool, buffer, params);
649 result = GST_FLOW_NOT_SUPPORTED;
651 if (G_LIKELY (result == GST_FLOW_OK)) {
652 /* all buffers from the pool point to the pool and have the refcount of the
653 * pool incremented */
654 (*buffer)->pool = gst_object_ref (pool);
656 dec_outstanding (pool);
663 default_release_buffer (GstBufferPool * pool, GstBuffer * buffer)
665 /* keep it around in our queue */
666 gst_atomic_queue_push (pool->queue, buffer);
667 gst_poll_write_control (pool->poll);
671 * gst_buffer_pool_release_buffer:
672 * @pool: a #GstBufferPool
673 * @buffer: a #GstBuffer
675 * Release @buffer to @pool. @buffer should have previously been allocated from
676 * @pool with gst_buffer_pool_acquire_buffer().
678 * This function is usually called automatically when the last ref on @buffer
682 gst_buffer_pool_release_buffer (GstBufferPool * pool, GstBuffer * buffer)
684 GstBufferPoolClass *pclass;
686 g_return_if_fail (GST_IS_BUFFER_POOL (pool));
687 g_return_if_fail (buffer != NULL);
689 /* check that the buffer is ours, all buffers returned to the pool have the
690 * pool member set to NULL and the pool refcount decreased */
691 if (!g_atomic_pointer_compare_and_exchange ((gpointer *) & buffer->pool,
695 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
697 if (G_LIKELY (pclass->release_buffer))
698 pclass->release_buffer (pool, buffer);
700 dec_outstanding (pool);
702 /* decrease the refcount that the buffer had to us */
703 gst_object_unref (pool);