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;
170 gst_buffer_take_memory (*buffer, gst_memory_new_alloc (priv->size, align));
175 /* the default implementation for preallocating the buffers
178 default_start (GstBufferPool * pool)
181 GstBufferPoolPrivate *priv = pool->priv;
182 GstBufferPoolClass *pclass;
184 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
186 /* no alloc function, error */
187 if (G_UNLIKELY (pclass->alloc_buffer == NULL))
190 /* we need to prealloc buffers */
191 for (i = 0; i < priv->min_buffers; i++) {
194 if (pclass->alloc_buffer (pool, &buffer, NULL) != GST_FLOW_OK)
197 GST_LOG_OBJECT (pool, "prealloced buffer %d: %p", i, buffer);
198 /* store in the queue */
199 gst_atomic_queue_push (pool->queue, buffer);
200 gst_poll_write_control (pool->poll);
207 GST_WARNING_OBJECT (pool, "no alloc function");
212 GST_WARNING_OBJECT (pool, "alloc function failed");
217 /* must be called with the lock */
219 do_start (GstBufferPool * pool)
221 if (!pool->started) {
222 GstBufferPoolClass *pclass;
224 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
226 GST_LOG_OBJECT (pool, "starting");
227 /* start the pool, subclasses should allocate buffers and put them
229 if (G_LIKELY (pclass->start)) {
230 if (!pclass->start (pool))
233 pool->started = TRUE;
240 default_free_buffer (GstBufferPool * pool, GstBuffer * buffer)
242 gst_buffer_unref (buffer);
245 /* must be called with the lock */
247 default_stop (GstBufferPool * pool)
250 GstBufferPoolClass *pclass;
252 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
255 while ((buffer = gst_atomic_queue_pop (pool->queue))) {
256 gst_poll_read_control (pool->poll);
258 if (G_LIKELY (pclass->free_buffer))
259 pclass->free_buffer (pool, buffer);
264 /* must be called with the lock */
266 do_stop (GstBufferPool * pool)
269 GstBufferPoolClass *pclass;
271 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
273 GST_LOG_OBJECT (pool, "stopping");
274 if (G_LIKELY (pclass->stop)) {
275 if (!pclass->stop (pool))
278 pool->started = FALSE;
284 * gst_buffer_pool_set_active:
285 * @pool: a #GstBufferPool
286 * @active: the new active state
288 * Control the active state of @pool. When the pool is active, new calls to
289 * gst_buffer_pool_acquire_buffer() will return with GST_FLOW_WRONG_STATE.
291 * Returns: %FALSE when the pool was not configured or when preallocation of the
295 gst_buffer_pool_set_active (GstBufferPool * pool, gboolean active)
299 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), FALSE);
301 GST_LOG_OBJECT (pool, "active %d", active);
303 GST_BUFFER_POOL_LOCK (pool);
304 /* just return if we are already in the right state */
305 if (pool->active == active)
308 /* we need to be configured */
309 if (!pool->configured)
313 if (!do_start (pool))
316 /* unset the flushing state now */
317 gst_poll_read_control (pool->poll);
318 g_atomic_int_set (&pool->flushing, FALSE);
320 /* set to flushing first */
321 g_atomic_int_set (&pool->flushing, TRUE);
322 gst_poll_write_control (pool->poll);
324 /* when all buffers are in the pool, free them. Else they will be
325 * freed when they are released */
326 if (g_atomic_int_get (&pool->outstanding) == 0) {
331 pool->active = active;
332 GST_BUFFER_POOL_UNLOCK (pool);
338 GST_DEBUG_OBJECT (pool, "pool was in the right state");
339 GST_BUFFER_POOL_UNLOCK (pool);
344 GST_ERROR_OBJECT (pool, "pool was not configured");
345 GST_BUFFER_POOL_UNLOCK (pool);
350 GST_ERROR_OBJECT (pool, "start failed");
351 GST_BUFFER_POOL_UNLOCK (pool);
356 GST_WARNING_OBJECT (pool, "stop failed");
357 GST_BUFFER_POOL_UNLOCK (pool);
363 default_set_config (GstBufferPool * pool, GstStructure * config)
365 GstBufferPoolPrivate *priv = pool->priv;
367 guint size, min_buffers, max_buffers;
368 guint prefix, postfix, align;
370 /* parse the config and keep around */
371 if (!gst_buffer_pool_config_get (config, &caps, &size, &min_buffers,
372 &max_buffers, &prefix, &postfix, &align))
375 GST_DEBUG_OBJECT (pool, "config %" GST_PTR_FORMAT, config);
378 priv->min_buffers = min_buffers;
379 priv->max_buffers = max_buffers;
380 priv->prefix = prefix;
381 priv->postfix = postfix;
388 GST_WARNING_OBJECT (pool, "invalid config %" GST_PTR_FORMAT, config);
394 * gst_buffer_pool_set_config:
395 * @pool: a #GstBufferPool
396 * @config: a #GstStructure
398 * Set the configuration of the pool. The pool must be inactive and all buffers
399 * allocated form this pool must be returned or else this function will do
400 * nothing and return FALSE.
402 * @condfig is a #GstStructure that contains the configuration parameters for
403 * the pool. A default and mandatory set of parameters can be configured with
404 * gst_buffer_pool_config_set(). This function takes ownership of @config.
406 * Returns: TRUE when the configuration could be set.
409 gst_buffer_pool_set_config (GstBufferPool * pool, GstStructure * config)
412 GstBufferPoolClass *pclass;
414 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), FALSE);
415 g_return_val_if_fail (config != NULL, FALSE);
417 GST_BUFFER_POOL_LOCK (pool);
418 /* can't change the settings when active */
422 /* we can't change when outstanding buffers */
423 if (g_atomic_int_get (&pool->outstanding) != 0)
424 goto have_outstanding;
426 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
428 /* set the new config */
429 if (G_LIKELY (pclass->set_config))
430 result = pclass->set_config (pool, config);
436 gst_structure_free (pool->config);
437 pool->config = config;
439 /* now we are configured */
440 pool->configured = TRUE;
442 GST_BUFFER_POOL_UNLOCK (pool);
449 GST_WARNING_OBJECT (pool, "can't change config, we are active");
450 GST_BUFFER_POOL_UNLOCK (pool);
455 GST_WARNING_OBJECT (pool, "can't change config, have outstanding buffers");
456 GST_BUFFER_POOL_UNLOCK (pool);
462 * gst_buffer_pool_get_config:
463 * @pool: a #GstBufferPool
465 * Get a copy of the current configuration of the pool. This configuration
466 * can either be modified and used for the gst_buffer_pool_set_config() call
467 * or it must be freed after usage.
469 * Returns: a copy of the current configuration of @pool. use
470 * gst_structure_free() after usage or gst_buffer_pool_set_config().
473 gst_buffer_pool_get_config (GstBufferPool * pool)
475 GstStructure *result;
477 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), NULL);
479 GST_BUFFER_POOL_UNLOCK (pool);
480 result = gst_structure_copy (pool->config);
481 GST_BUFFER_POOL_UNLOCK (pool);
487 * gst_buffer_pool_config_set:
488 * @config: a #GstBufferPool
489 * @caps: caps for the buffers
490 * @size: the size of each buffer, not including pre and post fix
491 * @min_buffers: the minimum amount of buffers to allocate.
492 * @max_buffers: the maximum amount of buffers to allocate or 0 for unlimited.
493 * @prefix: prefix each buffer with this many bytes
494 * @postfix: postfix each buffer with this many bytes
495 * @align: alignment of the buffer data.
497 * Configure @config with the given parameters.
500 gst_buffer_pool_config_set (GstStructure * config, const GstCaps * caps,
501 guint size, guint min_buffers, guint max_buffers, guint prefix,
502 guint postfix, guint align)
504 g_return_if_fail (config != NULL);
506 gst_structure_id_set (config,
507 GST_QUARK (CAPS), GST_TYPE_CAPS, caps,
508 GST_QUARK (SIZE), G_TYPE_UINT, size,
509 GST_QUARK (MIN_BUFFERS), G_TYPE_UINT, min_buffers,
510 GST_QUARK (MAX_BUFFERS), G_TYPE_UINT, max_buffers,
511 GST_QUARK (PREFIX), G_TYPE_UINT, prefix,
512 GST_QUARK (POSTFIX), G_TYPE_UINT, postfix,
513 GST_QUARK (ALIGN), G_TYPE_UINT, align, NULL);
517 * gst_buffer_pool_config_get:
518 * @config: a #GstBufferPool
519 * @caps: the caps of buffers
520 * @size: the size of each buffer, not including pre and post fix
521 * @min_buffers: the minimum amount of buffers to allocate.
522 * @max_buffers: the maximum amount of buffers to allocate or 0 for unlimited.
523 * @prefix: prefix each buffer with this many bytes
524 * @postfix: postfix each buffer with this many bytes
525 * @align: alignment of the buffer data.
527 * Get the configuration values from @config.
530 gst_buffer_pool_config_get (GstStructure * config, const GstCaps ** caps,
531 guint * size, guint * min_buffers, guint * max_buffers, guint * prefix,
532 guint * postfix, guint * align)
534 g_return_val_if_fail (config != NULL, FALSE);
536 return gst_structure_id_get (config,
537 GST_QUARK (CAPS), GST_TYPE_CAPS, caps,
538 GST_QUARK (SIZE), G_TYPE_UINT, size,
539 GST_QUARK (MIN_BUFFERS), G_TYPE_UINT, min_buffers,
540 GST_QUARK (MAX_BUFFERS), G_TYPE_UINT, max_buffers,
541 GST_QUARK (PREFIX), G_TYPE_UINT, prefix,
542 GST_QUARK (POSTFIX), G_TYPE_UINT, postfix,
543 GST_QUARK (ALIGN), G_TYPE_UINT, align, NULL);
547 default_acquire_buffer (GstBufferPool * pool, GstBuffer ** buffer,
548 GstBufferPoolParams * params)
550 GstFlowReturn result;
551 GstBufferPoolClass *pclass;
552 GstBufferPoolPrivate *priv = pool->priv;
554 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
557 if (G_UNLIKELY (g_atomic_int_get (&pool->flushing)))
560 /* try to get a buffer from the queue */
561 *buffer = gst_atomic_queue_pop (pool->queue);
562 if (G_LIKELY (*buffer)) {
563 gst_poll_read_control (pool->poll);
564 result = GST_FLOW_OK;
565 GST_LOG_OBJECT (pool, "acquired buffer %p", *buffer);
570 if (priv->max_buffers == 0) {
571 /* no max_buffers, we allocate some more */
572 if (G_LIKELY (pclass->alloc_buffer)) {
573 result = pclass->alloc_buffer (pool, buffer, params);
575 result = GST_FLOW_NOT_SUPPORTED;
576 GST_LOG_OBJECT (pool, "alloc buffer %p", *buffer);
580 /* check if we need to wait */
581 if (params && (params->flags & GST_BUFFER_POOL_FLAG_DONTWAIT)) {
582 GST_LOG_OBJECT (pool, "no more buffers");
583 result = GST_FLOW_UNEXPECTED;
588 GST_LOG_OBJECT (pool, "waiting for free buffers");
589 gst_poll_wait (pool->poll, GST_CLOCK_TIME_NONE);
597 GST_DEBUG_OBJECT (pool, "we are flushing");
598 return GST_FLOW_WRONG_STATE;
603 dec_outstanding (GstBufferPool * pool)
605 if (g_atomic_int_dec_and_test (&pool->outstanding)) {
606 /* all buffers are returned to the pool, see if we need to free them */
607 if (g_atomic_int_get (&pool->flushing)) {
608 /* take the lock so that set_active is not run concurrently */
609 GST_BUFFER_POOL_LOCK (pool);
610 /* recheck the flushing state in the lock, the pool could have been
611 * set to active again */
612 if (g_atomic_int_get (&pool->flushing))
615 GST_BUFFER_POOL_UNLOCK (pool);
621 * gst_buffer_pool_acquire_buffer:
622 * @pool: a #GstBufferPool
623 * @buffer: a location for a #GstBuffer
624 * @params: parameters.
626 * Acquire a buffer from @pool. @buffer should point to a memory location that
627 * can hold a pointer to the new buffer.
629 * @params can be NULL or contain optional parameters to influence the allocation.
631 * Returns: a #GstFlowReturn such as GST_FLOW_WRONG_STATE when the pool is
635 gst_buffer_pool_acquire_buffer (GstBufferPool * pool, GstBuffer ** buffer,
636 GstBufferPoolParams * params)
638 GstBufferPoolClass *pclass;
639 GstFlowReturn result;
641 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), GST_FLOW_ERROR);
642 g_return_val_if_fail (buffer != NULL, GST_FLOW_ERROR);
644 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
646 /* assume we'll have one more outstanding buffer we need to do that so
647 * that concurrent set_active doesn't clear the buffers */
648 g_atomic_int_inc (&pool->outstanding);
650 if (G_LIKELY (pclass->acquire_buffer))
651 result = pclass->acquire_buffer (pool, buffer, params);
653 result = GST_FLOW_NOT_SUPPORTED;
655 if (G_LIKELY (result == GST_FLOW_OK)) {
656 /* all buffers from the pool point to the pool and have the refcount of the
657 * pool incremented */
658 (*buffer)->pool = gst_object_ref (pool);
660 dec_outstanding (pool);
667 default_release_buffer (GstBufferPool * pool, GstBuffer * buffer)
669 /* keep it around in our queue */
670 GST_LOG_OBJECT (pool, "released buffer %p", buffer);
671 gst_atomic_queue_push (pool->queue, buffer);
672 gst_poll_write_control (pool->poll);
676 * gst_buffer_pool_release_buffer:
677 * @pool: a #GstBufferPool
678 * @buffer: a #GstBuffer
680 * Release @buffer to @pool. @buffer should have previously been allocated from
681 * @pool with gst_buffer_pool_acquire_buffer().
683 * This function is usually called automatically when the last ref on @buffer
687 gst_buffer_pool_release_buffer (GstBufferPool * pool, GstBuffer * buffer)
689 GstBufferPoolClass *pclass;
691 g_return_if_fail (GST_IS_BUFFER_POOL (pool));
692 g_return_if_fail (buffer != NULL);
694 /* check that the buffer is ours, all buffers returned to the pool have the
695 * pool member set to NULL and the pool refcount decreased */
696 if (!g_atomic_pointer_compare_and_exchange ((gpointer *) & buffer->pool,
700 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
702 if (G_LIKELY (pclass->release_buffer))
703 pclass->release_buffer (pool, buffer);
705 dec_outstanding (pool);
707 /* decrease the refcount that the buffer had to us */
708 gst_object_unref (pool);