/* 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:gstbufferpool
* @title: GstBufferPool
* @short_description: Pool for buffers
* @see_also: #GstBuffer
*
* A #GstBufferPool is an object that can be used to pre-allocate and recycle
* buffers of the same size and with the same properties.
*
* A #GstBufferPool is created with gst_buffer_pool_new().
*
* Once a pool is created, it needs to be configured. A call to
* gst_buffer_pool_get_config() returns the current configuration structure from
* the pool. With gst_buffer_pool_config_set_params() and
* gst_buffer_pool_config_set_allocator() the bufferpool parameters and
* allocator can be configured. Other properties can be configured in the pool
* depending on the pool implementation.
*
* A bufferpool can have extra options that can be enabled with
* gst_buffer_pool_config_add_option(). The available options can be retrieved
* with gst_buffer_pool_get_options(). Some options allow for additional
* configuration properties to be set.
*
* After the configuration structure has been configured,
* gst_buffer_pool_set_config() updates the configuration in the pool. This can
* fail when the configuration structure is not accepted.
*
* After the a pool has been configured, it can be activated with
* gst_buffer_pool_set_active(). This will preallocate the configured resources
* in the pool.
*
* When the pool is active, gst_buffer_pool_acquire_buffer() can be used to
* retrieve a buffer from the pool.
*
* Buffers allocated from a bufferpool will automatically be returned to the
* pool with gst_buffer_pool_release_buffer() when their refcount drops to 0.
*
* The bufferpool can be deactivated again with gst_buffer_pool_set_active().
* All further gst_buffer_pool_acquire_buffer() calls will return an error. When
* all buffers are returned to the pool they will be freed.
*
* Use gst_object_unref() to release the reference to a bufferpool. If the
* refcount of the pool reaches 0, the pool will be freed.
*/
#include "gst_private.h"
#include "glib-compat-private.h"
#include <errno.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#include <sys/types.h>
#include "gstatomicqueue.h"
#include "gstpoll.h"
#include "gstinfo.h"
#include "gstquark.h"
#include "gstvalue.h"
#include "gstbufferpool.h"
#ifdef G_OS_WIN32
# ifndef EWOULDBLOCK
# define EWOULDBLOCK EAGAIN /* This is just to placate gcc */
# endif
#endif /* G_OS_WIN32 */
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_rec_mutex_lock(&pool->priv->rec_lock))
#define GST_BUFFER_POOL_UNLOCK(pool) (g_rec_mutex_unlock(&pool->priv->rec_lock))
struct _GstBufferPoolPrivate
{
GstAtomicQueue *queue;
GstPoll *poll;
GRecMutex rec_lock;
gboolean started;
gboolean active;
gint outstanding; /* number of buffers that are in use */
gboolean configured;
GstStructure *config;
guint size;
guint min_buffers;
guint max_buffers;
guint cur_buffers;
GstAllocator *allocator;
GstAllocationParams params;
};
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, GstBufferPoolAcquireParams * params);
static GstFlowReturn default_acquire_buffer (GstBufferPool * pool,
GstBuffer ** buffer, GstBufferPoolAcquireParams * params);
static void default_reset_buffer (GstBufferPool * pool, GstBuffer * buffer);
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->reset_buffer = default_reset_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)
{
GstBufferPoolPrivate *priv;
priv = pool->priv = GST_BUFFER_POOL_GET_PRIVATE (pool);
g_rec_mutex_init (&priv->rec_lock);
priv->poll = gst_poll_new_timer ();
priv->queue = gst_atomic_queue_new (16);
pool->flushing = 1;
priv->active = FALSE;
priv->configured = FALSE;
priv->started = FALSE;
priv->config = gst_structure_new_id_empty (GST_QUARK (BUFFER_POOL_CONFIG));
gst_buffer_pool_config_set_params (priv->config, NULL, 0, 0, 0);
priv->allocator = NULL;
gst_allocation_params_init (&priv->params);
gst_buffer_pool_config_set_allocator (priv->config, priv->allocator,
&priv->params);
/* 1 control write for flushing - the flush token */
gst_poll_write_control (priv->poll);
/* 1 control write for marking that we are not waiting for poll - the wait token */
gst_poll_write_control (priv->poll);
GST_DEBUG_OBJECT (pool, "created");
}
static void
gst_buffer_pool_finalize (GObject * object)
{
GstBufferPool *pool;
GstBufferPoolPrivate *priv;
pool = GST_BUFFER_POOL_CAST (object);
priv = pool->priv;
GST_DEBUG_OBJECT (pool, "%p finalize", pool);
gst_buffer_pool_set_active (pool, FALSE);
gst_atomic_queue_unref (priv->queue);
gst_poll_free (priv->poll);
gst_structure_free (priv->config);
g_rec_mutex_clear (&priv->rec_lock);
if (priv->allocator)
gst_object_unref (priv->allocator);
G_OBJECT_CLASS (gst_buffer_pool_parent_class)->finalize (object);
}
/**
* gst_buffer_pool_new:
*
* Creates a new #GstBufferPool instance.
*
* Returns: (transfer full): a new #GstBufferPool instance
*/
GstBufferPool *
gst_buffer_pool_new (void)
{
GstBufferPool *result;
result = g_object_new (GST_TYPE_BUFFER_POOL, NULL);
GST_DEBUG_OBJECT (result, "created new buffer pool");
/* Clear floating flag */
gst_object_ref_sink (result);
return result;
}
static GstFlowReturn
default_alloc_buffer (GstBufferPool * pool, GstBuffer ** buffer,
GstBufferPoolAcquireParams * params)
{
GstBufferPoolPrivate *priv = pool->priv;
*buffer =
gst_buffer_new_allocate (priv->allocator, priv->size, &priv->params);
if (!*buffer)
return GST_FLOW_ERROR;
return GST_FLOW_OK;
}
static gboolean
mark_meta_pooled (GstBuffer * buffer, GstMeta ** meta, gpointer user_data)
{
GST_DEBUG_OBJECT (GST_BUFFER_POOL (user_data),
"marking meta %p as POOLED in buffer %p", *meta, buffer);
GST_META_FLAG_SET (*meta, GST_META_FLAG_POOLED);
GST_META_FLAG_SET (*meta, GST_META_FLAG_LOCKED);
return TRUE;
}
static GstFlowReturn
do_alloc_buffer (GstBufferPool * pool, GstBuffer ** buffer,
GstBufferPoolAcquireParams * params)
{
GstBufferPoolPrivate *priv = pool->priv;
GstFlowReturn result;
gint cur_buffers, max_buffers;
GstBufferPoolClass *pclass;
pclass = GST_BUFFER_POOL_GET_CLASS (pool);
if (G_UNLIKELY (!pclass->alloc_buffer))
goto no_function;
max_buffers = priv->max_buffers;
/* increment the allocation counter */
cur_buffers = g_atomic_int_add (&priv->cur_buffers, 1);
if (max_buffers && cur_buffers >= max_buffers)
goto max_reached;
result = pclass->alloc_buffer (pool, buffer, params);
if (G_UNLIKELY (result != GST_FLOW_OK))
goto alloc_failed;
/* lock all metadata and mark as pooled, we want this to remain on
* the buffer and we want to remove any other metadata that gets added
* later */
gst_buffer_foreach_meta (*buffer, mark_meta_pooled, pool);
/* un-tag memory, this is how we expect the buffer when it is
* released again */
GST_BUFFER_FLAG_UNSET (*buffer, GST_BUFFER_FLAG_TAG_MEMORY);
GST_LOG_OBJECT (pool, "allocated buffer %d/%d, %p", cur_buffers,
max_buffers, *buffer);
return result;
/* ERRORS */
no_function:
{
GST_ERROR_OBJECT (pool, "no alloc function");
return GST_FLOW_NOT_SUPPORTED;
}
max_reached:
{
GST_DEBUG_OBJECT (pool, "max buffers reached");
g_atomic_int_add (&priv->cur_buffers, -1);
return GST_FLOW_EOS;
}
alloc_failed:
{
GST_WARNING_OBJECT (pool, "alloc function failed");
g_atomic_int_add (&priv->cur_buffers, -1);
return result;
}
}
/* 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);
/* we need to prealloc buffers */
for (i = 0; i < priv->min_buffers; i++) {
GstBuffer *buffer;
if (do_alloc_buffer (pool, &buffer, NULL) != GST_FLOW_OK)
goto alloc_failed;
/* release to the queue, we call the vmethod directly, we don't need to do
* the other refcount handling right now. */
if (G_LIKELY (pclass->release_buffer))
pclass->release_buffer (pool, buffer);
}
return TRUE;
/* ERRORS */
alloc_failed:
{
GST_WARNING_OBJECT (pool, "failed to allocate buffer");
return FALSE;
}
}
/* must be called with the lock */
static gboolean
do_start (GstBufferPool * pool)
{
GstBufferPoolPrivate *priv = pool->priv;
if (!priv->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;
}
priv->started = TRUE;
}
return TRUE;
}
static void
default_free_buffer (GstBufferPool * pool, GstBuffer * buffer)
{
gst_buffer_unref (buffer);
}
static void
do_free_buffer (GstBufferPool * pool, GstBuffer * buffer)
{
GstBufferPoolPrivate *priv;
GstBufferPoolClass *pclass;
priv = pool->priv;
pclass = GST_BUFFER_POOL_GET_CLASS (pool);
g_atomic_int_add (&priv->cur_buffers, -1);
GST_LOG_OBJECT (pool, "freeing buffer %p (%u left)", buffer,
priv->cur_buffers);
if (G_LIKELY (pclass->free_buffer))
pclass->free_buffer (pool, buffer);
}
/* must be called with the lock */
static gboolean
default_stop (GstBufferPool * pool)
{
GstBufferPoolPrivate *priv = pool->priv;
GstBuffer *buffer;
/* clear the pool */
while ((buffer = gst_atomic_queue_pop (priv->queue))) {
while (!gst_poll_read_control (priv->poll)) {
if (errno == EWOULDBLOCK) {
/* We put the buffer into the queue but did not finish writing control
* yet, let's wait a bit and retry */
g_thread_yield ();
continue;
} else {
/* Critical error but GstPoll already complained */
break;
}
}
do_free_buffer (pool, buffer);
}
return priv->cur_buffers == 0;
}
/* must be called with the lock */
static gboolean
do_stop (GstBufferPool * pool)
{
GstBufferPoolPrivate *priv = pool->priv;
if (priv->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;
}
priv->started = FALSE;
}
return TRUE;
}
/* must be called with the lock */
static void
do_set_flushing (GstBufferPool * pool, gboolean flushing)
{
GstBufferPoolPrivate *priv = pool->priv;
GstBufferPoolClass *pclass;
pclass = GST_BUFFER_POOL_GET_CLASS (pool);
if (GST_BUFFER_POOL_IS_FLUSHING (pool) == flushing)
return;
if (flushing) {
g_atomic_int_set (&pool->flushing, 1);
/* Write the flush token to wake up any waiters */
gst_poll_write_control (priv->poll);
if (pclass->flush_start)
pclass->flush_start (pool);
} else {
if (pclass->flush_stop)
pclass->flush_stop (pool);
while (!gst_poll_read_control (priv->poll)) {
if (errno == EWOULDBLOCK) {
/* This should not really happen unless flushing and unflushing
* happens on different threads. Let's wait a bit to get back flush
* token from the thread that was setting it to flushing */
g_thread_yield ();
continue;
} else {
/* Critical error but GstPoll already complained */
break;
}
}
g_atomic_int_set (&pool->flushing, 0);
}
}
/**
* gst_buffer_pool_set_active:
* @pool: a #GstBufferPool
* @active: the new active state
*
* Control the active state of @pool. When the pool is inactive, new calls to
* gst_buffer_pool_acquire_buffer() will return with %GST_FLOW_FLUSHING.
*
* Activating the bufferpool will preallocate all resources in the pool based on
* the configuration of the pool.
*
* Deactivating will free the resources again when there are no outstanding
* buffers. When there are outstanding buffers, they will be freed as soon as
* they are all returned to the pool.
*
* 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;
GstBufferPoolPrivate *priv;
g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), FALSE);
GST_LOG_OBJECT (pool, "active %d", active);
priv = pool->priv;
GST_BUFFER_POOL_LOCK (pool);
/* just return if we are already in the right state */
if (priv->active == active)
goto was_ok;
/* we need to be configured */
if (!priv->configured)
goto not_configured;
if (active) {
if (!do_start (pool))
goto start_failed;
/* flush_stop my release buffers, setting to active to avoid running
* do_stop while activating the pool */
priv->active = TRUE;
/* unset the flushing state now */
do_set_flushing (pool, FALSE);
} else {
gint outstanding;
/* set to flushing first */
do_set_flushing (pool, TRUE);
/* when all buffers are in the pool, free them. Else they will be
* freed when they are released */
outstanding = g_atomic_int_get (&priv->outstanding);
GST_LOG_OBJECT (pool, "outstanding buffers %d", outstanding);
if (outstanding == 0) {
if (!do_stop (pool))
goto stop_failed;
}
priv->active = FALSE;
}
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;
}
}
/**
* gst_buffer_pool_is_active:
* @pool: a #GstBufferPool
*
* Check if @pool is active. A pool can be activated with the
* gst_buffer_pool_set_active() call.
*
* Returns: %TRUE when the pool is active.
*/
gboolean
gst_buffer_pool_is_active (GstBufferPool * pool)
{
gboolean res;
GST_BUFFER_POOL_LOCK (pool);
res = pool->priv->active;
GST_BUFFER_POOL_UNLOCK (pool);
return res;
}
static gboolean
default_set_config (GstBufferPool * pool, GstStructure * config)
{
GstBufferPoolPrivate *priv = pool->priv;
GstCaps *caps;
guint size, min_buffers, max_buffers;
GstAllocator *allocator;
GstAllocationParams params;
/* parse the config and keep around */
if (!gst_buffer_pool_config_get_params (config, &caps, &size, &min_buffers,
&max_buffers))
goto wrong_config;
if (!gst_buffer_pool_config_get_allocator (config, &allocator, ¶ms))
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->cur_buffers = 0;
if (priv->allocator)
gst_object_unref (priv->allocator);
if ((priv->allocator = allocator))
gst_object_ref (allocator);
priv->params = params;
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: (transfer full): a #GstStructure
*
* Set the configuration of the pool. If the pool is already configured, and
* the configuration haven't change, this function will return %TRUE. If the
* pool is active, this method will return %FALSE and active configuration
* will remain. Buffers allocated form this pool must be returned or else this
* function will do nothing and return %FALSE.
*
* @config 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_params(), gst_buffer_pool_config_set_allocator()
* and gst_buffer_pool_config_add_option().
*
* If the parameters in @config can not be set exactly, this function returns
* %FALSE and will try to update as much state as possible. The new state can
* then be retrieved and refined with gst_buffer_pool_get_config().
*
* 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;
GstBufferPoolPrivate *priv;
g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), FALSE);
g_return_val_if_fail (config != NULL, FALSE);
priv = pool->priv;
GST_BUFFER_POOL_LOCK (pool);
/* nothing to do if config is unchanged */
if (priv->configured && gst_structure_is_equal (config, priv->config))
goto config_unchanged;
/* can't change the settings when active */
if (priv->active)
goto was_active;
/* we can't change when outstanding buffers */
if (g_atomic_int_get (&priv->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;
/* save the config regardless of the result so user can read back the
* modified config and evaluate if the changes are acceptable */
if (priv->config)
gst_structure_free (priv->config);
priv->config = config;
if (result) {
/* now we are configured */
priv->configured = TRUE;
}
GST_BUFFER_POOL_UNLOCK (pool);
return result;
config_unchanged:
{
gst_structure_free (config);
GST_BUFFER_POOL_UNLOCK (pool);
return TRUE;
}
/* ERRORS */
was_active:
{
gst_structure_free (config);
GST_INFO_OBJECT (pool, "can't change config, we are active");
GST_BUFFER_POOL_UNLOCK (pool);
return FALSE;
}
have_outstanding:
{
gst_structure_free (config);
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: (transfer full): 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_LOCK (pool);
result = gst_structure_copy (pool->priv->config);
GST_BUFFER_POOL_UNLOCK (pool);
return result;
}
static const gchar *empty_option[] = { NULL };
/**
* gst_buffer_pool_get_options:
* @pool: a #GstBufferPool
*
* Get a %NULL terminated array of string with supported bufferpool options for
* @pool. An option would typically be enabled with
* gst_buffer_pool_config_add_option().
*
* Returns: (array zero-terminated=1) (transfer none): a %NULL terminated array
* of strings.
*/
const gchar **
gst_buffer_pool_get_options (GstBufferPool * pool)
{
GstBufferPoolClass *pclass;
const gchar **result;
g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), NULL);
pclass = GST_BUFFER_POOL_GET_CLASS (pool);
if (G_LIKELY (pclass->get_options)) {
if ((result = pclass->get_options (pool)) == NULL)
goto invalid_result;
} else
result = empty_option;
return result;
/* ERROR */
invalid_result:
{
g_warning ("bufferpool subclass returned NULL options");
return empty_option;
}
}
/**
* gst_buffer_pool_has_option:
* @pool: a #GstBufferPool
* @option: an option
*
* Check if the bufferpool supports @option.
*
* Returns: %TRUE if the buffer pool contains @option.
*/
gboolean
gst_buffer_pool_has_option (GstBufferPool * pool, const gchar * option)
{
guint i;
const gchar **options;
g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), FALSE);
g_return_val_if_fail (option != NULL, FALSE);
options = gst_buffer_pool_get_options (pool);
for (i = 0; options[i]; i++) {
if (g_str_equal (options[i], option))
return TRUE;
}
return FALSE;
}
/**
* gst_buffer_pool_config_set_params:
* @config: a #GstBufferPool configuration
* @caps: caps for the buffers
* @size: the size of each buffer, not including prefix and padding
* @min_buffers: the minimum amount of buffers to allocate.
* @max_buffers: the maximum amount of buffers to allocate or 0 for unlimited.
*
* Configure @config with the given parameters.
*/
void
gst_buffer_pool_config_set_params (GstStructure * config, GstCaps * caps,
guint size, guint min_buffers, guint max_buffers)
{
g_return_if_fail (config != NULL);
g_return_if_fail (max_buffers == 0 || min_buffers <= max_buffers);
g_return_if_fail (caps == NULL || gst_caps_is_fixed (caps));
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, NULL);
}
/**
* gst_buffer_pool_config_set_allocator:
* @config: a #GstBufferPool configuration
* @allocator: (allow-none): a #GstAllocator
* @params: (allow-none): #GstAllocationParams
*
* Set the @allocator and @params on @config.
*
* One of @allocator and @params can be %NULL, but not both. When @allocator
* is %NULL, the default allocator of the pool will use the values in @param
* to perform its allocation. When @param is %NULL, the pool will use the
* provided @allocator with its default #GstAllocationParams.
*
* A call to gst_buffer_pool_set_config() can update the allocator and params
* with the values that it is able to do. Some pools are, for example, not able
* to operate with different allocators or cannot allocate with the values
* specified in @params. Use gst_buffer_pool_get_config() to get the currently
* used values.
*/
void
gst_buffer_pool_config_set_allocator (GstStructure * config,
GstAllocator * allocator, const GstAllocationParams * params)
{
g_return_if_fail (config != NULL);
g_return_if_fail (allocator != NULL || params != NULL);
gst_structure_id_set (config,
GST_QUARK (ALLOCATOR), GST_TYPE_ALLOCATOR, allocator,
GST_QUARK (PARAMS), GST_TYPE_ALLOCATION_PARAMS, params, NULL);
}
/**
* gst_buffer_pool_config_add_option:
* @config: a #GstBufferPool configuration
* @option: an option to add
*
* Enabled the option in @config. This will instruct the @bufferpool to enable
* the specified option on the buffers that it allocates.
*
* The supported options by @pool can be retrieved with gst_buffer_pool_get_options().
*/
void
gst_buffer_pool_config_add_option (GstStructure * config, const gchar * option)
{
const GValue *value;
GValue option_value = { 0, };
guint i, len;
g_return_if_fail (config != NULL);
value = gst_structure_id_get_value (config, GST_QUARK (OPTIONS));
if (value) {
len = gst_value_array_get_size (value);
for (i = 0; i < len; ++i) {
const GValue *nth_val = gst_value_array_get_value (value, i);
if (g_str_equal (option, g_value_get_string (nth_val)))
return;
}
} else {
GValue new_array_val = { 0, };
g_value_init (&new_array_val, GST_TYPE_ARRAY);
gst_structure_id_take_value (config, GST_QUARK (OPTIONS), &new_array_val);
value = gst_structure_id_get_value (config, GST_QUARK (OPTIONS));
}
g_value_init (&option_value, G_TYPE_STRING);
g_value_set_string (&option_value, option);
gst_value_array_append_and_take_value ((GValue *) value, &option_value);
}
/**
* gst_buffer_pool_config_n_options:
* @config: a #GstBufferPool configuration
*
* Retrieve the number of values currently stored in the options array of the
* @config structure.
*
* Returns: the options array size as a #guint.
*/
guint
gst_buffer_pool_config_n_options (GstStructure * config)
{
const GValue *value;
guint size = 0;
g_return_val_if_fail (config != NULL, 0);
value = gst_structure_id_get_value (config, GST_QUARK (OPTIONS));
if (value) {
size = gst_value_array_get_size (value);
}
return size;
}
/**
* gst_buffer_pool_config_get_option:
* @config: a #GstBufferPool configuration
* @index: position in the option array to read
*
* Parse an available @config and get the option at @index of the options API
* array.
*
* Returns: a #gchar of the option at @index.
*/
const gchar *
gst_buffer_pool_config_get_option (GstStructure * config, guint index)
{
const GValue *value;
const gchar *ret = NULL;
g_return_val_if_fail (config != NULL, 0);
value = gst_structure_id_get_value (config, GST_QUARK (OPTIONS));
if (value) {
const GValue *option_value;
option_value = gst_value_array_get_value (value, index);
if (option_value)
ret = g_value_get_string (option_value);
}
return ret;
}
/**
* gst_buffer_pool_config_has_option:
* @config: a #GstBufferPool configuration
* @option: an option
*
* Check if @config contains @option.
*
* Returns: %TRUE if the options array contains @option.
*/
gboolean
gst_buffer_pool_config_has_option (GstStructure * config, const gchar * option)
{
const GValue *value;
guint i, len;
g_return_val_if_fail (config != NULL, 0);
value = gst_structure_id_get_value (config, GST_QUARK (OPTIONS));
if (value) {
len = gst_value_array_get_size (value);
for (i = 0; i < len; ++i) {
const GValue *nth_val = gst_value_array_get_value (value, i);
if (g_str_equal (option, g_value_get_string (nth_val)))
return TRUE;
}
}
return FALSE;
}
/**
* gst_buffer_pool_config_get_params:
* @config: (transfer none): a #GstBufferPool configuration
* @caps: (out) (transfer none) (allow-none): the caps of buffers
* @size: (out) (allow-none): the size of each buffer, not including prefix and padding
* @min_buffers: (out) (allow-none): the minimum amount of buffers to allocate.
* @max_buffers: (out) (allow-none): the maximum amount of buffers to allocate or 0 for unlimited.
*
* Get the configuration values from @config.
*
* Returns: %TRUE if all parameters could be fetched.
*/
gboolean
gst_buffer_pool_config_get_params (GstStructure * config, GstCaps ** caps,
guint * size, guint * min_buffers, guint * max_buffers)
{
g_return_val_if_fail (config != NULL, FALSE);
if (caps) {
*caps = g_value_get_boxed (gst_structure_id_get_value (config,
GST_QUARK (CAPS)));
}
return gst_structure_id_get (config,
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, NULL);
}
/**
* gst_buffer_pool_config_get_allocator:
* @config: (transfer none): a #GstBufferPool configuration
* @allocator: (out) (allow-none) (transfer none): a #GstAllocator, or %NULL
* @params: (out) (allow-none): #GstAllocationParams, or %NULL
*
* Get the @allocator and @params from @config.
*
* Returns: %TRUE, if the values are set.
*/
gboolean
gst_buffer_pool_config_get_allocator (GstStructure * config,
GstAllocator ** allocator, GstAllocationParams * params)
{
g_return_val_if_fail (config != NULL, FALSE);
if (allocator)
*allocator = g_value_get_object (gst_structure_id_get_value (config,
GST_QUARK (ALLOCATOR)));
if (params) {
GstAllocationParams *p;
p = g_value_get_boxed (gst_structure_id_get_value (config,
GST_QUARK (PARAMS)));
if (p) {
*params = *p;
} else {
gst_allocation_params_init (params);
}
}
return TRUE;
}
/**
* gst_buffer_pool_config_validate_params:
* @config: (transfer none): a #GstBufferPool configuration
* @caps: (transfer none): the excepted caps of buffers
* @size: the expected size of each buffer, not including prefix and padding
* @min_buffers: the expected minimum amount of buffers to allocate.
* @max_buffers: the expect maximum amount of buffers to allocate or 0 for unlimited.
*
* Validate that changes made to @config are still valid in the context of the
* expected parameters. This function is a helper that can be used to validate
* changes made by a pool to a config when gst_buffer_pool_set_config()
* returns %FALSE. This expects that @caps haven't changed and that
* @min_buffers aren't lower then what we initially expected.
* This does not check if options or allocator parameters are still valid,
* won't check if size have changed, since changing the size is valid to adapt
* padding.
*
* Since: 1.4
*
* Returns: %TRUE, if the parameters are valid in this context.
*/
gboolean
gst_buffer_pool_config_validate_params (GstStructure * config, GstCaps * caps,
guint size, guint min_buffers, G_GNUC_UNUSED guint max_buffers)
{
GstCaps *newcaps;
guint newsize, newmin;
gboolean ret = FALSE;
g_return_val_if_fail (config != NULL, FALSE);
gst_buffer_pool_config_get_params (config, &newcaps, &newsize, &newmin, NULL);
if (gst_caps_is_equal (caps, newcaps) && (newsize >= size)
&& (newmin >= min_buffers))
ret = TRUE;
return ret;
}
static GstFlowReturn
default_acquire_buffer (GstBufferPool * pool, GstBuffer ** buffer,
GstBufferPoolAcquireParams * params)
{
GstFlowReturn result;
GstBufferPoolPrivate *priv = pool->priv;
while (TRUE) {
if (G_UNLIKELY (GST_BUFFER_POOL_IS_FLUSHING (pool)))
goto flushing;
/* try to get a buffer from the queue */
*buffer = gst_atomic_queue_pop (priv->queue);
if (G_LIKELY (*buffer)) {
while (!gst_poll_read_control (priv->poll)) {
if (errno == EWOULDBLOCK) {
/* We put the buffer into the queue but did not finish writing control
* yet, let's wait a bit and retry */
g_thread_yield ();
continue;
} else {
/* Critical error but GstPoll already complained */
break;
}
}
result = GST_FLOW_OK;
GST_LOG_OBJECT (pool, "acquired buffer %p", *buffer);
break;
}
/* no buffer, try to allocate some more */
GST_LOG_OBJECT (pool, "no buffer, trying to allocate");
result = do_alloc_buffer (pool, buffer, params);
if (G_LIKELY (result == GST_FLOW_OK))
/* we have a buffer, return it */
break;
if (G_UNLIKELY (result != GST_FLOW_EOS))
/* something went wrong, return error */
break;
/* check if we need to wait */
if (params && (params->flags & GST_BUFFER_POOL_ACQUIRE_FLAG_DONTWAIT)) {
GST_LOG_OBJECT (pool, "no more buffers");
break;
}
/* now we release the control socket, we wait for a buffer release or
* flushing */
if (!gst_poll_read_control (pool->priv->poll)) {
if (errno == EWOULDBLOCK) {
/* This means that we have two threads trying to allocate buffers
* already, and the other one already got the wait token. This
* means that we only have to wait for the poll now and not write the
* token afterwards: we will be woken up once the other thread is
* woken up and that one will write the wait token it removed */
GST_LOG_OBJECT (pool, "waiting for free buffers or flushing");
gst_poll_wait (priv->poll, GST_CLOCK_TIME_NONE);
} else {
/* This is a critical error, GstPoll already gave a warning */
result = GST_FLOW_ERROR;
break;
}
} else {
/* We're the first thread waiting, we got the wait token and have to
* write it again later
* OR
* We're a second thread and just consumed the flush token and block all
* other threads, in which case we must not wait and give it back
* immediately */
if (!GST_BUFFER_POOL_IS_FLUSHING (pool)) {
GST_LOG_OBJECT (pool, "waiting for free buffers or flushing");
gst_poll_wait (priv->poll, GST_CLOCK_TIME_NONE);
}
gst_poll_write_control (pool->priv->poll);
}
}
return result;
/* ERRORS */
flushing:
{
GST_DEBUG_OBJECT (pool, "we are flushing");
return GST_FLOW_FLUSHING;
}
}
static inline void
dec_outstanding (GstBufferPool * pool)
{
if (g_atomic_int_dec_and_test (&pool->priv->outstanding)) {
/* all buffers are returned to the pool, see if we need to free them */
if (GST_BUFFER_POOL_IS_FLUSHING (pool)) {
/* take the lock so that set_active is not run concurrently */
GST_BUFFER_POOL_LOCK (pool);
/* now that we have the lock, check if we have been de-activated with
* outstanding buffers */
if (!pool->priv->active)
do_stop (pool);
GST_BUFFER_POOL_UNLOCK (pool);
}
}
}
static gboolean
remove_meta_unpooled (GstBuffer * buffer, GstMeta ** meta, gpointer user_data)
{
if (!GST_META_FLAG_IS_SET (*meta, GST_META_FLAG_POOLED)) {
GST_META_FLAG_UNSET (*meta, GST_META_FLAG_LOCKED);
*meta = NULL;
}
return TRUE;
}
static void
default_reset_buffer (GstBufferPool * pool, GstBuffer * buffer)
{
GST_BUFFER_FLAGS (buffer) &= GST_BUFFER_FLAG_TAG_MEMORY;
GST_BUFFER_PTS (buffer) = GST_CLOCK_TIME_NONE;
GST_BUFFER_DTS (buffer) = GST_CLOCK_TIME_NONE;
GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE;
GST_BUFFER_OFFSET (buffer) = GST_BUFFER_OFFSET_NONE;
GST_BUFFER_OFFSET_END (buffer) = GST_BUFFER_OFFSET_NONE;
/* remove all metadata without the POOLED flag */
gst_buffer_foreach_meta (buffer, remove_meta_unpooled, pool);
}
/**
* gst_buffer_pool_acquire_buffer:
* @pool: a #GstBufferPool
* @buffer: (out): a location for a #GstBuffer
* @params: (transfer none) (allow-none): 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_FLUSHING when the pool is
* inactive.
*/
GstFlowReturn
gst_buffer_pool_acquire_buffer (GstBufferPool * pool, GstBuffer ** buffer,
GstBufferPoolAcquireParams * 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->priv->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)
{
GST_LOG_OBJECT (pool, "released buffer %p %d", buffer,
GST_MINI_OBJECT_FLAGS (buffer));
/* memory should be untouched */
if (G_UNLIKELY (GST_BUFFER_FLAG_IS_SET (buffer, GST_BUFFER_FLAG_TAG_MEMORY)))
goto memory_tagged;
/* size should have been reset. This is not a catch all, pool with
* size requirement per memory should do their own check. */
if (G_UNLIKELY (gst_buffer_get_size (buffer) != pool->priv->size))
goto size_changed;
/* all memory should be exclusive to this buffer (and thus be writable) */
if (G_UNLIKELY (!gst_buffer_is_all_memory_writable (buffer)))
goto not_writable;
/* keep it around in our queue */
gst_atomic_queue_push (pool->priv->queue, buffer);
gst_poll_write_control (pool->priv->poll);
return;
memory_tagged:
{
GST_CAT_DEBUG_OBJECT (GST_CAT_PERFORMANCE, pool,
"discarding buffer %p: memory tag set", buffer);
goto discard;
}
size_changed:
{
GST_CAT_DEBUG_OBJECT (GST_CAT_PERFORMANCE, pool,
"discarding buffer %p: size %" G_GSIZE_FORMAT " != %u",
buffer, gst_buffer_get_size (buffer), pool->priv->size);
goto discard;
}
not_writable:
{
GST_CAT_DEBUG_OBJECT (GST_CAT_PERFORMANCE, pool,
"discarding buffer %p: memory not writable", buffer);
goto discard;
}
discard:
{
do_free_buffer (pool, buffer);
return;
}
}
/**
* gst_buffer_pool_release_buffer:
* @pool: a #GstBufferPool
* @buffer: (transfer full): 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 (&buffer->pool, pool, NULL))
return;
pclass = GST_BUFFER_POOL_GET_CLASS (pool);
/* reset the buffer when needed */
if (G_LIKELY (pclass->reset_buffer))
pclass->reset_buffer (pool, buffer);
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);
}
/**
* gst_buffer_pool_set_flushing:
* @pool: a #GstBufferPool
* @flushing: whether to start or stop flushing
*
* Enable or disable the flushing state of a @pool without freeing or
* allocating buffers.
*
* Since: 1.4
*/
void
gst_buffer_pool_set_flushing (GstBufferPool * pool, gboolean flushing)
{
GstBufferPoolPrivate *priv;
g_return_if_fail (GST_IS_BUFFER_POOL (pool));
GST_LOG_OBJECT (pool, "flushing %d", flushing);
priv = pool->priv;
GST_BUFFER_POOL_LOCK (pool);
if (!priv->active) {
GST_WARNING_OBJECT (pool, "can't change flushing state of inactive pool");
goto done;
}
do_set_flushing (pool, flushing);
done:
GST_BUFFER_POOL_UNLOCK (pool);
}