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;
67 static void gst_buffer_pool_finalize (GObject * object);
69 G_DEFINE_TYPE (GstBufferPool, gst_buffer_pool, GST_TYPE_OBJECT);
71 static gboolean default_start (GstBufferPool * pool);
72 static gboolean default_stop (GstBufferPool * pool);
73 static gboolean default_set_config (GstBufferPool * pool,
74 GstStructure * config);
75 static GstFlowReturn default_alloc_buffer (GstBufferPool * pool,
76 GstBuffer ** buffer, GstBufferPoolParams * params);
77 static GstFlowReturn default_acquire_buffer (GstBufferPool * pool,
78 GstBuffer ** buffer, GstBufferPoolParams * params);
79 static void default_free_buffer (GstBufferPool * pool, GstBuffer * buffer);
80 static void default_release_buffer (GstBufferPool * pool, GstBuffer * buffer);
83 gst_buffer_pool_class_init (GstBufferPoolClass * klass)
85 GObjectClass *gobject_class = (GObjectClass *) klass;
87 g_type_class_add_private (klass, sizeof (GstBufferPoolPrivate));
89 gobject_class->finalize = gst_buffer_pool_finalize;
91 klass->start = default_start;
92 klass->stop = default_stop;
93 klass->set_config = default_set_config;
94 klass->acquire_buffer = default_acquire_buffer;
95 klass->alloc_buffer = default_alloc_buffer;
96 klass->release_buffer = default_release_buffer;
97 klass->free_buffer = default_free_buffer;
99 GST_DEBUG_CATEGORY_INIT (gst_buffer_pool_debug, "bufferpool", 0,
104 gst_buffer_pool_init (GstBufferPool * pool)
106 pool->priv = GST_BUFFER_POOL_GET_PRIVATE (pool);
108 g_static_rec_mutex_init (&pool->priv->rec_lock);
110 pool->poll = gst_poll_new_timer ();
111 pool->queue = gst_atomic_queue_new (10);
112 pool->flushing = TRUE;
113 pool->active = FALSE;
114 pool->configured = FALSE;
115 pool->started = FALSE;
116 pool->config = gst_structure_id_empty_new (GST_QUARK (BUFFER_POOL_CONFIG));
117 gst_buffer_pool_config_set (pool->config, NULL, 0, 0, 0, 0, 1);
119 GST_DEBUG_OBJECT (pool, "created");
123 gst_buffer_pool_finalize (GObject * object)
127 pool = GST_BUFFER_POOL_CAST (object);
129 GST_DEBUG_OBJECT (pool, "finalize");
131 gst_buffer_pool_set_active (pool, FALSE);
132 gst_atomic_queue_unref (pool->queue);
133 gst_poll_free (pool->poll);
134 gst_structure_free (pool->config);
135 g_static_rec_mutex_free (&pool->priv->rec_lock);
137 G_OBJECT_CLASS (gst_buffer_pool_parent_class)->finalize (object);
141 * gst_buffer_pool_new:
143 * Creates a new #GstBufferPool instance.
145 * Returns: a new #GstBufferPool instance
148 gst_buffer_pool_new (void)
150 GstBufferPool *result;
152 result = g_object_newv (GST_TYPE_BUFFER_POOL, 0, NULL);
153 GST_DEBUG_OBJECT (result, "created new buffer pool");
159 default_alloc_buffer (GstBufferPool * pool, GstBuffer ** buffer,
160 GstBufferPoolParams * params)
162 GstBufferPoolPrivate *priv = pool->priv;
165 *buffer = gst_buffer_new ();
168 gst_memory_allocator_alloc (NULL, priv->size + priv->prefix, priv->align);
169 gst_memory_resize (mem, priv->prefix, priv->size);
170 gst_buffer_take_memory (*buffer, -1, mem);
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;
370 /* parse the config and keep around */
371 if (!gst_buffer_pool_config_get (config, &caps, &size, &min_buffers,
372 &max_buffers, &prefix, &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;
387 GST_WARNING_OBJECT (pool, "invalid config %" GST_PTR_FORMAT, config);
393 * gst_buffer_pool_set_config:
394 * @pool: a #GstBufferPool
395 * @config: a #GstStructure
397 * Set the configuration of the pool. The pool must be inactive and all buffers
398 * allocated form this pool must be returned or else this function will do
399 * nothing and return FALSE.
401 * @condfig is a #GstStructure that contains the configuration parameters for
402 * the pool. A default and mandatory set of parameters can be configured with
403 * gst_buffer_pool_config_set(). This function takes ownership of @config.
405 * Returns: TRUE when the configuration could be set.
408 gst_buffer_pool_set_config (GstBufferPool * pool, GstStructure * config)
411 GstBufferPoolClass *pclass;
413 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), FALSE);
414 g_return_val_if_fail (config != NULL, FALSE);
416 GST_BUFFER_POOL_LOCK (pool);
417 /* can't change the settings when active */
421 /* we can't change when outstanding buffers */
422 if (g_atomic_int_get (&pool->outstanding) != 0)
423 goto have_outstanding;
425 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
427 /* set the new config */
428 if (G_LIKELY (pclass->set_config))
429 result = pclass->set_config (pool, config);
435 gst_structure_free (pool->config);
436 pool->config = config;
438 /* now we are configured */
439 pool->configured = TRUE;
441 GST_BUFFER_POOL_UNLOCK (pool);
448 GST_WARNING_OBJECT (pool, "can't change config, we are active");
449 GST_BUFFER_POOL_UNLOCK (pool);
454 GST_WARNING_OBJECT (pool, "can't change config, have outstanding buffers");
455 GST_BUFFER_POOL_UNLOCK (pool);
461 * gst_buffer_pool_get_config:
462 * @pool: a #GstBufferPool
464 * Get a copy of the current configuration of the pool. This configuration
465 * can either be modified and used for the gst_buffer_pool_set_config() call
466 * or it must be freed after usage.
468 * Returns: a copy of the current configuration of @pool. use
469 * gst_structure_free() after usage or gst_buffer_pool_set_config().
472 gst_buffer_pool_get_config (GstBufferPool * pool)
474 GstStructure *result;
476 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), NULL);
478 GST_BUFFER_POOL_UNLOCK (pool);
479 result = gst_structure_copy (pool->config);
480 GST_BUFFER_POOL_UNLOCK (pool);
485 static const gchar *empty_meta[] = { NULL };
488 * gst_buffer_pool_get_metas:
489 * @pool: a #GstBufferPool
491 * Get a NULL terminated array of string with supported #GstMeta apis for
492 * @pool. The requested api would typically be added to the config with
493 * gst_buffer_pool_config_add_meta().
495 * Returns: a NULL terminated array of strings.
498 gst_buffer_pool_get_metas (GstBufferPool * pool)
500 GstBufferPoolClass *pclass;
501 const gchar **result;
503 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), NULL);
505 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
507 if (G_LIKELY (pclass->get_metas))
508 result = pclass->get_metas (pool);
516 * gst_buffer_pool_config_set:
517 * @config: a #GstBufferPool configuration
518 * @caps: caps for the buffers
519 * @size: the size of each buffer, not including prefix
520 * @min_buffers: the minimum amount of buffers to allocate.
521 * @max_buffers: the maximum amount of buffers to allocate or 0 for unlimited.
522 * @prefix: prefix each buffer with this many bytes
523 * @align: alignment of the buffer data.
525 * Configure @config with the given parameters.
528 gst_buffer_pool_config_set (GstStructure * config, const GstCaps * caps,
529 guint size, guint min_buffers, guint max_buffers, guint prefix, guint align)
531 g_return_if_fail (config != NULL);
533 gst_structure_id_set (config,
534 GST_QUARK (CAPS), GST_TYPE_CAPS, caps,
535 GST_QUARK (SIZE), G_TYPE_UINT, size,
536 GST_QUARK (MIN_BUFFERS), G_TYPE_UINT, min_buffers,
537 GST_QUARK (MAX_BUFFERS), G_TYPE_UINT, max_buffers,
538 GST_QUARK (PREFIX), G_TYPE_UINT, prefix,
539 GST_QUARK (ALIGN), G_TYPE_UINT, align, NULL);
543 * gst_buffer_pool_config_add_meta:
544 * @config: a #GstBufferPool configuration
545 * @api: an API to add
547 * Adds the metadata api to @config. This will instruct the @bufferpool to use
548 * the specified metadata api on the buffers that it allocates.
550 * The supported API by @pool can be retrieved with gst_buffer_pool_get_metas().
553 gst_buffer_pool_config_add_meta (GstStructure * config, const gchar * api)
557 GValue api_value = { 0 };
559 g_return_if_fail (config != NULL);
561 value = gst_structure_id_get_value (config, GST_QUARK (META));
563 array = (GValueArray *) g_value_get_boxed (value);
565 GValue new_array_val = { 0, };
567 array = g_value_array_new (0);
569 g_value_init (&new_array_val, G_TYPE_VALUE_ARRAY);
570 g_value_take_boxed (&new_array_val, array);
572 gst_structure_id_take_value (config, GST_QUARK (META), &new_array_val);
575 g_value_init (&api_value, G_TYPE_STRING);
576 g_value_set_string (&api_value, api);
577 g_value_array_append (array, &api_value);
578 g_value_unset (&api_value);
582 * gst_buffer_pool_config_n_metas:
583 * @config: a #GstBufferPool configuration
585 * Retrieve the number of values currently stored in the
586 * meta API array of the @config structure.
588 * Returns: the metadata API array size as a #guint.
591 gst_buffer_pool_config_n_metas (GstStructure * config)
597 g_return_val_if_fail (config != NULL, 0);
599 value = gst_structure_id_get_value (config, GST_QUARK (META));
601 array = (GValueArray *) g_value_get_boxed (value);
602 size = array->n_values;
608 * gst_buffer_pool_config_get_meta:
609 * @config: a #GstBufferPool configuration
610 * @index: position in the metadata API array to read
612 * Parse an available @config and get the metadata API
613 * at @index of the metadata API array.
615 * Returns: a #gchar of the metadata API at @index.
618 gst_buffer_pool_config_get_meta (GstStructure * config, guint index)
621 const gchar *ret = NULL;
623 g_return_val_if_fail (config != NULL, 0);
625 value = gst_structure_id_get_value (config, GST_QUARK (META));
630 meta = (GValueArray *) g_value_get_boxed (value);
631 api_value = g_value_array_get_nth (meta, index);
634 ret = g_value_get_string (api_value);
640 * gst_buffer_pool_config_has_meta:
641 * @config: a #GstBufferPool configuration
642 * @api: a metadata api
644 * Check if @config contains @api metadata.
646 * Returns: TRUE if the metadata array contain @api.
649 gst_buffer_pool_config_has_meta (GstStructure * config, const gchar * api)
653 g_return_val_if_fail (config != NULL, 0);
655 value = gst_structure_id_get_value (config, GST_QUARK (META));
661 array = (GValueArray *) g_value_get_boxed (value);
662 for (i = 0; i < array->n_values; i++) {
663 api_value = g_value_array_get_nth (array, i);
664 if (!strcmp (api, g_value_get_string (api_value)))
672 * gst_buffer_pool_config_get:
673 * @config: a #GstBufferPool configuration
674 * @caps: the caps of buffers
675 * @size: the size of each buffer, not including prefix
676 * @min_buffers: the minimum amount of buffers to allocate.
677 * @max_buffers: the maximum amount of buffers to allocate or 0 for unlimited.
678 * @prefix: prefix each buffer with this many bytes
679 * @align: alignment of the buffer data.
681 * Get the configuration values from @config.
684 gst_buffer_pool_config_get (GstStructure * config, const GstCaps ** caps,
685 guint * size, guint * min_buffers, guint * max_buffers, guint * prefix,
688 g_return_val_if_fail (config != NULL, FALSE);
690 return gst_structure_id_get (config,
691 GST_QUARK (CAPS), GST_TYPE_CAPS, caps,
692 GST_QUARK (SIZE), G_TYPE_UINT, size,
693 GST_QUARK (MIN_BUFFERS), G_TYPE_UINT, min_buffers,
694 GST_QUARK (MAX_BUFFERS), G_TYPE_UINT, max_buffers,
695 GST_QUARK (PREFIX), G_TYPE_UINT, prefix,
696 GST_QUARK (ALIGN), G_TYPE_UINT, align, NULL);
700 default_acquire_buffer (GstBufferPool * pool, GstBuffer ** buffer,
701 GstBufferPoolParams * params)
703 GstFlowReturn result;
704 GstBufferPoolClass *pclass;
705 GstBufferPoolPrivate *priv = pool->priv;
707 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
710 if (G_UNLIKELY (g_atomic_int_get (&pool->flushing)))
713 /* try to get a buffer from the queue */
714 *buffer = gst_atomic_queue_pop (pool->queue);
715 if (G_LIKELY (*buffer)) {
716 gst_poll_read_control (pool->poll);
717 result = GST_FLOW_OK;
718 GST_LOG_OBJECT (pool, "acquired buffer %p", *buffer);
723 if (priv->max_buffers == 0) {
724 /* no max_buffers, we allocate some more */
725 if (G_LIKELY (pclass->alloc_buffer)) {
726 result = pclass->alloc_buffer (pool, buffer, params);
728 result = GST_FLOW_NOT_SUPPORTED;
729 GST_LOG_OBJECT (pool, "alloc buffer %p", *buffer);
733 /* check if we need to wait */
734 if (params && (params->flags & GST_BUFFER_POOL_FLAG_DONTWAIT)) {
735 GST_LOG_OBJECT (pool, "no more buffers");
736 result = GST_FLOW_UNEXPECTED;
741 GST_LOG_OBJECT (pool, "waiting for free buffers");
742 gst_poll_wait (pool->poll, GST_CLOCK_TIME_NONE);
750 GST_DEBUG_OBJECT (pool, "we are flushing");
751 return GST_FLOW_WRONG_STATE;
756 dec_outstanding (GstBufferPool * pool)
758 if (g_atomic_int_dec_and_test (&pool->outstanding)) {
759 /* all buffers are returned to the pool, see if we need to free them */
760 if (g_atomic_int_get (&pool->flushing)) {
761 /* take the lock so that set_active is not run concurrently */
762 GST_BUFFER_POOL_LOCK (pool);
763 /* recheck the flushing state in the lock, the pool could have been
764 * set to active again */
765 if (g_atomic_int_get (&pool->flushing))
768 GST_BUFFER_POOL_UNLOCK (pool);
774 * gst_buffer_pool_acquire_buffer:
775 * @pool: a #GstBufferPool
776 * @buffer: a location for a #GstBuffer
777 * @params: parameters.
779 * Acquire a buffer from @pool. @buffer should point to a memory location that
780 * can hold a pointer to the new buffer.
782 * @params can be NULL or contain optional parameters to influence the allocation.
784 * Returns: a #GstFlowReturn such as GST_FLOW_WRONG_STATE when the pool is
788 gst_buffer_pool_acquire_buffer (GstBufferPool * pool, GstBuffer ** buffer,
789 GstBufferPoolParams * params)
791 GstBufferPoolClass *pclass;
792 GstFlowReturn result;
794 g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), GST_FLOW_ERROR);
795 g_return_val_if_fail (buffer != NULL, GST_FLOW_ERROR);
797 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
799 /* assume we'll have one more outstanding buffer we need to do that so
800 * that concurrent set_active doesn't clear the buffers */
801 g_atomic_int_inc (&pool->outstanding);
803 if (G_LIKELY (pclass->acquire_buffer))
804 result = pclass->acquire_buffer (pool, buffer, params);
806 result = GST_FLOW_NOT_SUPPORTED;
808 if (G_LIKELY (result == GST_FLOW_OK)) {
809 /* all buffers from the pool point to the pool and have the refcount of the
810 * pool incremented */
811 (*buffer)->pool = gst_object_ref (pool);
813 dec_outstanding (pool);
820 default_release_buffer (GstBufferPool * pool, GstBuffer * buffer)
822 /* keep it around in our queue */
823 GST_LOG_OBJECT (pool, "released buffer %p", buffer);
824 gst_atomic_queue_push (pool->queue, buffer);
825 gst_poll_write_control (pool->poll);
829 * gst_buffer_pool_release_buffer:
830 * @pool: a #GstBufferPool
831 * @buffer: a #GstBuffer
833 * Release @buffer to @pool. @buffer should have previously been allocated from
834 * @pool with gst_buffer_pool_acquire_buffer().
836 * This function is usually called automatically when the last ref on @buffer
840 gst_buffer_pool_release_buffer (GstBufferPool * pool, GstBuffer * buffer)
842 GstBufferPoolClass *pclass;
844 g_return_if_fail (GST_IS_BUFFER_POOL (pool));
845 g_return_if_fail (buffer != NULL);
847 /* check that the buffer is ours, all buffers returned to the pool have the
848 * pool member set to NULL and the pool refcount decreased */
849 if (!g_atomic_pointer_compare_and_exchange ((gpointer *) & buffer->pool,
853 pclass = GST_BUFFER_POOL_GET_CLASS (pool);
855 if (G_LIKELY (pclass->release_buffer))
856 pclass->release_buffer (pool, buffer);
858 dec_outstanding (pool);
860 /* decrease the refcount that the buffer had to us */
861 gst_object_unref (pool);