gstreamer/gst/gstbufferpool.c
Wim Taymans 89121c18e5 bufferpool: make the default behaviour to wait
The most common case is to not specify any flags when doing the allocation. Make
the allocation from a pool with a maximum amount of buffers block by default for
this reason.
2011-06-03 12:40:56 +02:00

709 lines
19 KiB
C

/* GStreamer
* Copyright (C) 2010 Wim Taymans <wim.taymans@gmail.com>
*
* gstbufferpool.c: GstBufferPool baseclass
*
* 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.
*/
/**
* SECTION:gstbufferpool
* @short_description: Pool for buffers
* @see_also: #GstBuffer
*
*/
#include "gst_private.h"
#include <errno.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#include <sys/types.h>
#include "gstinfo.h"
#include "gstquark.h"
#include "gstbufferpool.h"
GST_DEBUG_CATEGORY_STATIC (gst_buffer_pool_debug);
#define GST_CAT_DEFAULT gst_buffer_pool_debug
#define GST_BUFFER_POOL_GET_PRIVATE(obj) \
(G_TYPE_INSTANCE_GET_PRIVATE ((obj), GST_TYPE_BUFFER_POOL, GstBufferPoolPrivate))
#define GST_BUFFER_POOL_LOCK(pool) (g_static_rec_mutex_lock(&pool->priv->rec_lock))
#define GST_BUFFER_POOL_UNLOCK(pool) (g_static_rec_mutex_unlock(&pool->priv->rec_lock))
struct _GstBufferPoolPrivate
{
GStaticRecMutex rec_lock;
guint size;
guint min_buffers;
guint max_buffers;
guint prefix;
guint postfix;
guint align;
};
enum
{
/* add more above */
LAST_SIGNAL
};
static void gst_buffer_pool_finalize (GObject * object);
G_DEFINE_TYPE (GstBufferPool, gst_buffer_pool, GST_TYPE_OBJECT);
static gboolean default_start (GstBufferPool * pool);
static gboolean default_stop (GstBufferPool * pool);
static gboolean default_set_config (GstBufferPool * pool,
GstStructure * config);
static GstFlowReturn default_alloc_buffer (GstBufferPool * pool,
GstBuffer ** buffer, GstBufferPoolParams * params);
static GstFlowReturn default_acquire_buffer (GstBufferPool * pool,
GstBuffer ** buffer, GstBufferPoolParams * params);
static void default_free_buffer (GstBufferPool * pool, GstBuffer * buffer);
static void default_release_buffer (GstBufferPool * pool, GstBuffer * buffer);
static void
gst_buffer_pool_class_init (GstBufferPoolClass * klass)
{
GObjectClass *gobject_class = (GObjectClass *) klass;
g_type_class_add_private (klass, sizeof (GstBufferPoolPrivate));
gobject_class->finalize = gst_buffer_pool_finalize;
klass->start = default_start;
klass->stop = default_stop;
klass->set_config = default_set_config;
klass->acquire_buffer = default_acquire_buffer;
klass->alloc_buffer = default_alloc_buffer;
klass->release_buffer = default_release_buffer;
klass->free_buffer = default_free_buffer;
GST_DEBUG_CATEGORY_INIT (gst_buffer_pool_debug, "bufferpool", 0,
"bufferpool debug");
}
static void
gst_buffer_pool_init (GstBufferPool * pool)
{
pool->priv = GST_BUFFER_POOL_GET_PRIVATE (pool);
g_static_rec_mutex_init (&pool->priv->rec_lock);
pool->poll = gst_poll_new_timer ();
pool->queue = gst_atomic_queue_new (10);
pool->flushing = TRUE;
pool->active = FALSE;
pool->configured = FALSE;
pool->started = FALSE;
pool->config = gst_structure_id_empty_new (GST_QUARK (BUFFER_POOL_CONFIG));
gst_buffer_pool_config_set (pool->config, NULL, 0, 0, 0, 0, 0, 1);
GST_DEBUG_OBJECT (pool, "created");
}
static void
gst_buffer_pool_finalize (GObject * object)
{
GstBufferPool *pool;
pool = GST_BUFFER_POOL_CAST (object);
GST_DEBUG_OBJECT (pool, "finalize");
gst_buffer_pool_set_active (pool, FALSE);
gst_atomic_queue_unref (pool->queue);
gst_poll_free (pool->poll);
gst_structure_free (pool->config);
g_static_rec_mutex_free (&pool->priv->rec_lock);
G_OBJECT_CLASS (gst_buffer_pool_parent_class)->finalize (object);
}
/**
* gst_buffer_pool_new:
*
* Creates a new #GstBufferPool instance.
*
* Returns: a new #GstBufferPool instance
*/
GstBufferPool *
gst_buffer_pool_new (void)
{
GstBufferPool *result;
result = g_object_newv (GST_TYPE_BUFFER_POOL, 0, NULL);
GST_DEBUG_OBJECT (result, "created new buffer pool");
return result;
}
static GstFlowReturn
default_alloc_buffer (GstBufferPool * pool, GstBuffer ** buffer,
GstBufferPoolParams * params)
{
guint align;
GstBufferPoolPrivate *priv = pool->priv;
*buffer = gst_buffer_new ();
align = priv->align - 1;
gst_buffer_take_memory (*buffer, gst_memory_new_alloc (priv->size, align));
return GST_FLOW_OK;
}
/* the default implementation for preallocating the buffers
* in the pool */
static gboolean
default_start (GstBufferPool * pool)
{
guint i;
GstBufferPoolPrivate *priv = pool->priv;
GstBufferPoolClass *pclass;
pclass = GST_BUFFER_POOL_GET_CLASS (pool);
/* no alloc function, error */
if (G_UNLIKELY (pclass->alloc_buffer == NULL))
goto no_alloc;
/* we need to prealloc buffers */
for (i = 0; i < priv->min_buffers; i++) {
GstBuffer *buffer;
if (pclass->alloc_buffer (pool, &buffer, NULL) != GST_FLOW_OK)
goto alloc_failed;
GST_LOG_OBJECT (pool, "prealloced buffer %d: %p", i, buffer);
/* store in the queue */
gst_atomic_queue_push (pool->queue, buffer);
gst_poll_write_control (pool->poll);
}
return TRUE;
/* ERRORS */
no_alloc:
{
GST_WARNING_OBJECT (pool, "no alloc function");
return FALSE;
}
alloc_failed:
{
GST_WARNING_OBJECT (pool, "alloc function failed");
return FALSE;
}
}
/* must be called with the lock */
static gboolean
do_start (GstBufferPool * pool)
{
if (!pool->started) {
GstBufferPoolClass *pclass;
pclass = GST_BUFFER_POOL_GET_CLASS (pool);
GST_LOG_OBJECT (pool, "starting");
/* start the pool, subclasses should allocate buffers and put them
* in the queue */
if (G_LIKELY (pclass->start)) {
if (!pclass->start (pool))
return FALSE;
}
pool->started = TRUE;
}
return TRUE;
}
static void
default_free_buffer (GstBufferPool * pool, GstBuffer * buffer)
{
gst_buffer_unref (buffer);
}
/* must be called with the lock */
static gboolean
default_stop (GstBufferPool * pool)
{
GstBuffer *buffer;
GstBufferPoolClass *pclass;
pclass = GST_BUFFER_POOL_GET_CLASS (pool);
/* clear the pool */
while ((buffer = gst_atomic_queue_pop (pool->queue))) {
gst_poll_read_control (pool->poll);
if (G_LIKELY (pclass->free_buffer))
pclass->free_buffer (pool, buffer);
}
return TRUE;
}
/* must be called with the lock */
static gboolean
do_stop (GstBufferPool * pool)
{
if (pool->started) {
GstBufferPoolClass *pclass;
pclass = GST_BUFFER_POOL_GET_CLASS (pool);
GST_LOG_OBJECT (pool, "stopping");
if (G_LIKELY (pclass->stop)) {
if (!pclass->stop (pool))
return FALSE;
}
pool->started = FALSE;
}
return TRUE;
}
/**
* gst_buffer_pool_set_active:
* @pool: a #GstBufferPool
* @active: the new active state
*
* Control the active state of @pool. When the pool is active, new calls to
* gst_buffer_pool_acquire_buffer() will return with GST_FLOW_WRONG_STATE.
*
* Returns: %FALSE when the pool was not configured or when preallocation of the
* buffers failed.
*/
gboolean
gst_buffer_pool_set_active (GstBufferPool * pool, gboolean active)
{
gboolean res = TRUE;
g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), FALSE);
GST_LOG_OBJECT (pool, "active %d", active);
GST_BUFFER_POOL_LOCK (pool);
/* just return if we are already in the right state */
if (pool->active == active)
goto was_ok;
/* we need to be configured */
if (!pool->configured)
goto not_configured;
if (active) {
if (!do_start (pool))
goto start_failed;
/* unset the flushing state now */
gst_poll_read_control (pool->poll);
g_atomic_int_set (&pool->flushing, FALSE);
} else {
/* set to flushing first */
g_atomic_int_set (&pool->flushing, TRUE);
gst_poll_write_control (pool->poll);
/* when all buffers are in the pool, free them. Else they will be
* freed when they are released */
if (g_atomic_int_get (&pool->outstanding) == 0) {
if (!do_stop (pool))
goto stop_failed;
}
}
pool->active = active;
GST_BUFFER_POOL_UNLOCK (pool);
return res;
was_ok:
{
GST_DEBUG_OBJECT (pool, "pool was in the right state");
GST_BUFFER_POOL_UNLOCK (pool);
return TRUE;
}
not_configured:
{
GST_ERROR_OBJECT (pool, "pool was not configured");
GST_BUFFER_POOL_UNLOCK (pool);
return FALSE;
}
start_failed:
{
GST_ERROR_OBJECT (pool, "start failed");
GST_BUFFER_POOL_UNLOCK (pool);
return FALSE;
}
stop_failed:
{
GST_WARNING_OBJECT (pool, "stop failed");
GST_BUFFER_POOL_UNLOCK (pool);
return FALSE;
}
}
static gboolean
default_set_config (GstBufferPool * pool, GstStructure * config)
{
GstBufferPoolPrivate *priv = pool->priv;
const GstCaps *caps;
guint size, min_buffers, max_buffers;
guint prefix, postfix, align;
/* parse the config and keep around */
if (!gst_buffer_pool_config_get (config, &caps, &size, &min_buffers,
&max_buffers, &prefix, &postfix, &align))
goto wrong_config;
GST_DEBUG_OBJECT (pool, "config %" GST_PTR_FORMAT, config);
priv->size = size;
priv->min_buffers = min_buffers;
priv->max_buffers = max_buffers;
priv->prefix = prefix;
priv->postfix = postfix;
priv->align = align;
return TRUE;
wrong_config:
{
GST_WARNING_OBJECT (pool, "invalid config %" GST_PTR_FORMAT, config);
return FALSE;
}
}
/**
* gst_buffer_pool_set_config:
* @pool: a #GstBufferPool
* @config: a #GstStructure
*
* Set the configuration of the pool. The pool must be inactive and all buffers
* allocated form this pool must be returned or else this function will do
* nothing and return FALSE.
*
* @condfig is a #GstStructure that contains the configuration parameters for
* the pool. A default and mandatory set of parameters can be configured with
* gst_buffer_pool_config_set(). This function takes ownership of @config.
*
* Returns: TRUE when the configuration could be set.
*/
gboolean
gst_buffer_pool_set_config (GstBufferPool * pool, GstStructure * config)
{
gboolean result;
GstBufferPoolClass *pclass;
g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), FALSE);
g_return_val_if_fail (config != NULL, FALSE);
GST_BUFFER_POOL_LOCK (pool);
/* can't change the settings when active */
if (pool->active)
goto was_active;
/* we can't change when outstanding buffers */
if (g_atomic_int_get (&pool->outstanding) != 0)
goto have_outstanding;
pclass = GST_BUFFER_POOL_GET_CLASS (pool);
/* set the new config */
if (G_LIKELY (pclass->set_config))
result = pclass->set_config (pool, config);
else
result = FALSE;
if (result) {
if (pool->config)
gst_structure_free (pool->config);
pool->config = config;
/* now we are configured */
pool->configured = TRUE;
}
GST_BUFFER_POOL_UNLOCK (pool);
return result;
/* ERRORS */
was_active:
{
GST_WARNING_OBJECT (pool, "can't change config, we are active");
GST_BUFFER_POOL_UNLOCK (pool);
return FALSE;
}
have_outstanding:
{
GST_WARNING_OBJECT (pool, "can't change config, have outstanding buffers");
GST_BUFFER_POOL_UNLOCK (pool);
return FALSE;
}
}
/**
* gst_buffer_pool_get_config:
* @pool: a #GstBufferPool
*
* Get a copy of the current configuration of the pool. This configuration
* can either be modified and used for the gst_buffer_pool_set_config() call
* or it must be freed after usage.
*
* Returns: a copy of the current configuration of @pool. use
* gst_structure_free() after usage or gst_buffer_pool_set_config().
*/
GstStructure *
gst_buffer_pool_get_config (GstBufferPool * pool)
{
GstStructure *result;
g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), NULL);
GST_BUFFER_POOL_UNLOCK (pool);
result = gst_structure_copy (pool->config);
GST_BUFFER_POOL_UNLOCK (pool);
return result;
}
/**
* gst_buffer_pool_config_set:
* @config: a #GstBufferPool
* @caps: caps for the buffers
* @size: the size of each buffer, not including pre and post fix
* @min_buffers: the minimum amount of buffers to allocate.
* @max_buffers: the maximum amount of buffers to allocate or 0 for unlimited.
* @prefix: prefix each buffer with this many bytes
* @postfix: postfix each buffer with this many bytes
* @align: alignment of the buffer data.
*
* Configure @config with the given parameters.
*/
void
gst_buffer_pool_config_set (GstStructure * config, const GstCaps * caps,
guint size, guint min_buffers, guint max_buffers, guint prefix,
guint postfix, guint align)
{
g_return_if_fail (config != NULL);
gst_structure_id_set (config,
GST_QUARK (CAPS), GST_TYPE_CAPS, caps,
GST_QUARK (SIZE), G_TYPE_UINT, size,
GST_QUARK (MIN_BUFFERS), G_TYPE_UINT, min_buffers,
GST_QUARK (MAX_BUFFERS), G_TYPE_UINT, max_buffers,
GST_QUARK (PREFIX), G_TYPE_UINT, prefix,
GST_QUARK (POSTFIX), G_TYPE_UINT, postfix,
GST_QUARK (ALIGN), G_TYPE_UINT, align, NULL);
}
/**
* gst_buffer_pool_config_get:
* @config: a #GstBufferPool
* @caps: the caps of buffers
* @size: the size of each buffer, not including pre and post fix
* @min_buffers: the minimum amount of buffers to allocate.
* @max_buffers: the maximum amount of buffers to allocate or 0 for unlimited.
* @prefix: prefix each buffer with this many bytes
* @postfix: postfix each buffer with this many bytes
* @align: alignment of the buffer data.
*
* Get the configuration values from @config.
*/
gboolean
gst_buffer_pool_config_get (GstStructure * config, const GstCaps ** caps,
guint * size, guint * min_buffers, guint * max_buffers, guint * prefix,
guint * postfix, guint * align)
{
g_return_val_if_fail (config != NULL, FALSE);
return gst_structure_id_get (config,
GST_QUARK (CAPS), GST_TYPE_CAPS, caps,
GST_QUARK (SIZE), G_TYPE_UINT, size,
GST_QUARK (MIN_BUFFERS), G_TYPE_UINT, min_buffers,
GST_QUARK (MAX_BUFFERS), G_TYPE_UINT, max_buffers,
GST_QUARK (PREFIX), G_TYPE_UINT, prefix,
GST_QUARK (POSTFIX), G_TYPE_UINT, postfix,
GST_QUARK (ALIGN), G_TYPE_UINT, align, NULL);
}
static GstFlowReturn
default_acquire_buffer (GstBufferPool * pool, GstBuffer ** buffer,
GstBufferPoolParams * params)
{
GstFlowReturn result;
GstBufferPoolClass *pclass;
GstBufferPoolPrivate *priv = pool->priv;
pclass = GST_BUFFER_POOL_GET_CLASS (pool);
while (TRUE) {
if (G_UNLIKELY (g_atomic_int_get (&pool->flushing)))
goto flushing;
/* try to get a buffer from the queue */
*buffer = gst_atomic_queue_pop (pool->queue);
if (G_LIKELY (*buffer)) {
gst_poll_read_control (pool->poll);
result = GST_FLOW_OK;
GST_LOG_OBJECT (pool, "acquired buffer %p", *buffer);
break;
}
/* no buffer */
if (priv->max_buffers == 0) {
/* no max_buffers, we allocate some more */
if (G_LIKELY (pclass->alloc_buffer)) {
result = pclass->alloc_buffer (pool, buffer, params);
} else
result = GST_FLOW_NOT_SUPPORTED;
GST_LOG_OBJECT (pool, "alloc buffer %p", *buffer);
break;
}
/* check if we need to wait */
if (params && (params->flags & GST_BUFFER_POOL_FLAG_DONTWAIT)) {
GST_LOG_OBJECT (pool, "no more buffers");
result = GST_FLOW_UNEXPECTED;
break;
}
/* now wait */
GST_LOG_OBJECT (pool, "waiting for free buffers");
gst_poll_wait (pool->poll, GST_CLOCK_TIME_NONE);
}
return result;
/* ERRORS */
flushing:
{
GST_DEBUG_OBJECT (pool, "we are flushing");
return GST_FLOW_WRONG_STATE;
}
}
static inline void
dec_outstanding (GstBufferPool * pool)
{
if (g_atomic_int_dec_and_test (&pool->outstanding)) {
/* all buffers are returned to the pool, see if we need to free them */
if (g_atomic_int_get (&pool->flushing)) {
/* take the lock so that set_active is not run concurrently */
GST_BUFFER_POOL_LOCK (pool);
/* recheck the flushing state in the lock, the pool could have been
* set to active again */
if (g_atomic_int_get (&pool->flushing))
do_stop (pool);
GST_BUFFER_POOL_UNLOCK (pool);
}
}
}
/**
* gst_buffer_pool_acquire_buffer:
* @pool: a #GstBufferPool
* @buffer: a location for a #GstBuffer
* @params: parameters.
*
* Acquire a buffer from @pool. @buffer should point to a memory location that
* can hold a pointer to the new buffer.
*
* @params can be NULL or contain optional parameters to influence the allocation.
*
* Returns: a #GstFlowReturn such as GST_FLOW_WRONG_STATE when the pool is
* inactive.
*/
GstFlowReturn
gst_buffer_pool_acquire_buffer (GstBufferPool * pool, GstBuffer ** buffer,
GstBufferPoolParams * params)
{
GstBufferPoolClass *pclass;
GstFlowReturn result;
g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), GST_FLOW_ERROR);
g_return_val_if_fail (buffer != NULL, GST_FLOW_ERROR);
pclass = GST_BUFFER_POOL_GET_CLASS (pool);
/* assume we'll have one more outstanding buffer we need to do that so
* that concurrent set_active doesn't clear the buffers */
g_atomic_int_inc (&pool->outstanding);
if (G_LIKELY (pclass->acquire_buffer))
result = pclass->acquire_buffer (pool, buffer, params);
else
result = GST_FLOW_NOT_SUPPORTED;
if (G_LIKELY (result == GST_FLOW_OK)) {
/* all buffers from the pool point to the pool and have the refcount of the
* pool incremented */
(*buffer)->pool = gst_object_ref (pool);
} else {
dec_outstanding (pool);
}
return result;
}
static void
default_release_buffer (GstBufferPool * pool, GstBuffer * buffer)
{
/* keep it around in our queue */
GST_LOG_OBJECT (pool, "released buffer %p", buffer);
gst_atomic_queue_push (pool->queue, buffer);
gst_poll_write_control (pool->poll);
}
/**
* gst_buffer_pool_release_buffer:
* @pool: a #GstBufferPool
* @buffer: a #GstBuffer
*
* Release @buffer to @pool. @buffer should have previously been allocated from
* @pool with gst_buffer_pool_acquire_buffer().
*
* This function is usually called automatically when the last ref on @buffer
* disappears.
*/
void
gst_buffer_pool_release_buffer (GstBufferPool * pool, GstBuffer * buffer)
{
GstBufferPoolClass *pclass;
g_return_if_fail (GST_IS_BUFFER_POOL (pool));
g_return_if_fail (buffer != NULL);
/* check that the buffer is ours, all buffers returned to the pool have the
* pool member set to NULL and the pool refcount decreased */
if (!g_atomic_pointer_compare_and_exchange ((gpointer *) & buffer->pool,
pool, NULL))
return;
pclass = GST_BUFFER_POOL_GET_CLASS (pool);
if (G_LIKELY (pclass->release_buffer))
pclass->release_buffer (pool, buffer);
dec_outstanding (pool);
/* decrease the refcount that the buffer had to us */
gst_object_unref (pool);
}