gstreamer/gst/gsttaskpool.c

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/* GStreamer
* Copyright (C) 2009 Wim Taymans <wim.taymans@gmail.com>
*
* gsttaskpool.c: Pool for streaming threads
*
* 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:gsttaskpool
* @title: GstTaskPool
* @short_description: Pool of GStreamer streaming threads
* @see_also: #GstTask, #GstPad
*
* This object provides an abstraction for creating threads. The default
* implementation uses a regular GThreadPool to start tasks.
*
* Subclasses can be made to create custom threads.
*/
#include "gst_private.h"
#include "gstinfo.h"
#include "gsttaskpool.h"
#include "gsterror.h"
GST_DEBUG_CATEGORY_STATIC (taskpool_debug);
#define GST_CAT_DEFAULT (taskpool_debug)
#ifndef GST_DISABLE_GST_DEBUG
static void gst_task_pool_finalize (GObject * object);
#endif
#define _do_init \
{ \
GST_DEBUG_CATEGORY_INIT (taskpool_debug, "taskpool", 0, "Thread pool"); \
}
G_DEFINE_TYPE_WITH_CODE (GstTaskPool, gst_task_pool, GST_TYPE_OBJECT, _do_init);
typedef struct
{
GstTaskPoolFunction func;
gpointer user_data;
} TaskData;
static void
default_func (TaskData * tdata, GstTaskPool * pool)
{
GstTaskPoolFunction func;
gpointer user_data;
func = tdata->func;
user_data = tdata->user_data;
g_slice_free (TaskData, tdata);
func (user_data);
}
static void
default_prepare (GstTaskPool * pool, GError ** error)
{
GST_OBJECT_LOCK (pool);
pool->pool = g_thread_pool_new ((GFunc) default_func, pool, -1, FALSE, error);
GST_OBJECT_UNLOCK (pool);
}
static void
default_cleanup (GstTaskPool * pool)
{
GThreadPool *pool_;
GST_OBJECT_LOCK (pool);
pool_ = pool->pool;
pool->pool = NULL;
GST_OBJECT_UNLOCK (pool);
if (pool_) {
/* Shut down all the threads, we still process the ones scheduled
* because the unref happens in the thread function.
* Also wait for currently running ones to finish. */
g_thread_pool_free (pool_, FALSE, TRUE);
}
}
static gpointer
default_push (GstTaskPool * pool, GstTaskPoolFunction func,
gpointer user_data, GError ** error)
{
TaskData *tdata;
tdata = g_slice_new (TaskData);
tdata->func = func;
tdata->user_data = user_data;
GST_OBJECT_LOCK (pool);
if (pool->pool)
g_thread_pool_push (pool->pool, tdata, error);
else {
g_slice_free (TaskData, tdata);
g_set_error_literal (error, GST_CORE_ERROR, GST_CORE_ERROR_FAILED,
"No thread pool");
}
GST_OBJECT_UNLOCK (pool);
return NULL;
}
static void
default_join (GstTaskPool * pool, gpointer id)
{
/* we do nothing here, we can't join from the pools */
}
static void
default_dispose_handle (GstTaskPool * pool, gpointer id)
{
/* we do nothing here, the default handle is NULL */
}
static void
gst_task_pool_class_init (GstTaskPoolClass * klass)
{
GObjectClass *gobject_class;
GstTaskPoolClass *gsttaskpool_class;
gobject_class = (GObjectClass *) klass;
gsttaskpool_class = (GstTaskPoolClass *) klass;
#ifndef GST_DISABLE_GST_DEBUG
gobject_class->finalize = gst_task_pool_finalize;
#endif
gsttaskpool_class->prepare = default_prepare;
gsttaskpool_class->cleanup = default_cleanup;
gsttaskpool_class->push = default_push;
gsttaskpool_class->join = default_join;
gsttaskpool_class->dispose_handle = default_dispose_handle;
}
static void
gst_task_pool_init (GstTaskPool * pool)
{
}
#ifndef GST_DISABLE_GST_DEBUG
static void
gst_task_pool_finalize (GObject * object)
{
GST_DEBUG ("taskpool %p finalize", object);
G_OBJECT_CLASS (gst_task_pool_parent_class)->finalize (object);
}
#endif
/**
* gst_task_pool_new:
*
* Create a new default task pool. The default task pool will use a regular
* GThreadPool for threads.
*
* Returns: (transfer full): a new #GstTaskPool. gst_object_unref() after usage.
*/
GstTaskPool *
gst_task_pool_new (void)
{
GstTaskPool *pool;
pool = g_object_new (GST_TYPE_TASK_POOL, NULL);
/* clear floating flag */
gst_object_ref_sink (pool);
return pool;
}
/**
* gst_task_pool_prepare:
* @pool: a #GstTaskPool
* @error: an error return location
*
* Prepare the taskpool for accepting gst_task_pool_push() operations.
*
* MT safe.
*/
void
gst_task_pool_prepare (GstTaskPool * pool, GError ** error)
{
GstTaskPoolClass *klass;
g_return_if_fail (GST_IS_TASK_POOL (pool));
klass = GST_TASK_POOL_GET_CLASS (pool);
if (klass->prepare)
klass->prepare (pool, error);
}
/**
* gst_task_pool_cleanup:
* @pool: a #GstTaskPool
*
* Wait for all tasks to be stopped. This is mainly used internally
* to ensure proper cleanup of internal data structures in test suites.
*
* MT safe.
*/
void
gst_task_pool_cleanup (GstTaskPool * pool)
{
GstTaskPoolClass *klass;
g_return_if_fail (GST_IS_TASK_POOL (pool));
klass = GST_TASK_POOL_GET_CLASS (pool);
if (klass->cleanup)
klass->cleanup (pool);
}
/**
* gst_task_pool_push:
* @pool: a #GstTaskPool
* @func: (scope async): the function to call
* @user_data: (closure): data to pass to @func
* @error: return location for an error
*
* Start the execution of a new thread from @pool.
*
* Returns: (transfer full) (nullable): a pointer that should be used
* for the gst_task_pool_join function. This pointer can be %NULL, you
* must check @error to detect errors. If the pointer is not %NULL and
* gst_task_pool_join() is not used, call gst_task_pool_dispose_handle()
* instead.
*/
gpointer
gst_task_pool_push (GstTaskPool * pool, GstTaskPoolFunction func,
gpointer user_data, GError ** error)
{
GstTaskPoolClass *klass;
g_return_val_if_fail (GST_IS_TASK_POOL (pool), NULL);
klass = GST_TASK_POOL_GET_CLASS (pool);
if (klass->push == NULL)
goto not_supported;
return klass->push (pool, func, user_data, error);
/* ERRORS */
not_supported:
{
g_warning ("pushing tasks on pool %p is not supported", pool);
return NULL;
}
}
/**
* gst_task_pool_join:
* @pool: a #GstTaskPool
* @id: (transfer full) (nullable): the id
*
* Join a task and/or return it to the pool. @id is the id obtained from
* gst_task_pool_push(). The default implementation does nothing, as the
* default #GstTaskPoolClass::push implementation always returns %NULL.
*
* This method should only be called with the same @pool instance that provided
* @id.
*/
void
gst_task_pool_join (GstTaskPool * pool, gpointer id)
{
GstTaskPoolClass *klass;
g_return_if_fail (GST_IS_TASK_POOL (pool));
klass = GST_TASK_POOL_GET_CLASS (pool);
if (klass->join)
klass->join (pool, id);
}
/**
* gst_task_pool_dispose_handle:
* @pool: a #GstTaskPool
* @id: (transfer full) (nullable): the id
*
* Dispose of the handle returned by gst_task_pool_push(). This does
* not need to be called with the default implementation as the default
* #GstTaskPoolClass::push implementation always returns %NULL. This does not need to be
* called either when calling gst_task_pool_join(), but should be called
* when joining is not necessary, but gst_task_pool_push() returned a
* non-%NULL value.
*
* This method should only be called with the same @pool instance that provided
* @id.
*
* Since: 1.20
*/
void
gst_task_pool_dispose_handle (GstTaskPool * pool, gpointer id)
{
GstTaskPoolClass *klass;
g_return_if_fail (GST_IS_TASK_POOL (pool));
klass = GST_TASK_POOL_GET_CLASS (pool);
if (klass->dispose_handle)
klass->dispose_handle (pool, id);
}
typedef struct
{
gboolean done;
guint64 id;
GstTaskPoolFunction func;
gpointer user_data;
GMutex done_lock;
GCond done_cond;
gint refcount;
} SharedTaskData;
static SharedTaskData *
shared_task_data_ref (SharedTaskData * tdata)
{
g_atomic_int_add (&tdata->refcount, 1);
return tdata;
}
static void
shared_task_data_unref (SharedTaskData * tdata)
{
if (g_atomic_int_dec_and_test (&tdata->refcount)) {
g_mutex_clear (&tdata->done_lock);
g_cond_clear (&tdata->done_cond);
g_slice_free (SharedTaskData, tdata);
}
}
struct _GstSharedTaskPoolPrivate
{
guint max_threads;
};
#define GST_SHARED_TASK_POOL_CAST(pool) ((GstSharedTaskPool*)(pool))
G_DEFINE_TYPE_WITH_PRIVATE (GstSharedTaskPool, gst_shared_task_pool,
GST_TYPE_TASK_POOL);
static void
shared_func (SharedTaskData * tdata, GstTaskPool * pool)
{
tdata->func (tdata->user_data);
g_mutex_lock (&tdata->done_lock);
tdata->done = TRUE;
g_cond_signal (&tdata->done_cond);
g_mutex_unlock (&tdata->done_lock);
shared_task_data_unref (tdata);
}
static gpointer
shared_push (GstTaskPool * pool, GstTaskPoolFunction func,
gpointer user_data, GError ** error)
{
SharedTaskData *ret = NULL;
GST_OBJECT_LOCK (pool);
if (!pool->pool) {
GST_OBJECT_UNLOCK (pool);
goto done;
}
ret = g_slice_new (SharedTaskData);
ret->done = FALSE;
ret->func = func;
ret->user_data = user_data;
g_atomic_int_set (&ret->refcount, 1);
g_cond_init (&ret->done_cond);
g_mutex_init (&ret->done_lock);
g_thread_pool_push (pool->pool, shared_task_data_ref (ret), error);
GST_OBJECT_UNLOCK (pool);
done:
return ret;
}
static void
shared_join (GstTaskPool * pool, gpointer id)
{
SharedTaskData *tdata;
if (!id)
return;
tdata = (SharedTaskData *) id;
g_mutex_lock (&tdata->done_lock);
while (!tdata->done) {
g_cond_wait (&tdata->done_cond, &tdata->done_lock);
}
g_mutex_unlock (&tdata->done_lock);
shared_task_data_unref (tdata);
}
static void
shared_dispose_handle (GstTaskPool * pool, gpointer id)
{
SharedTaskData *tdata;
if (!id)
return;
tdata = (SharedTaskData *) id;
shared_task_data_unref (tdata);
}
static void
shared_prepare (GstTaskPool * pool, GError ** error)
{
GstSharedTaskPool *shared_pool = GST_SHARED_TASK_POOL_CAST (pool);
GST_OBJECT_LOCK (pool);
pool->pool =
g_thread_pool_new ((GFunc) shared_func, pool,
shared_pool->priv->max_threads, FALSE, error);
GST_OBJECT_UNLOCK (pool);
}
static void
gst_shared_task_pool_class_init (GstSharedTaskPoolClass * klass)
{
GstTaskPoolClass *taskpoolclass = GST_TASK_POOL_CLASS (klass);
taskpoolclass->prepare = shared_prepare;
taskpoolclass->push = shared_push;
taskpoolclass->join = shared_join;
taskpoolclass->dispose_handle = shared_dispose_handle;
}
static void
gst_shared_task_pool_init (GstSharedTaskPool * pool)
{
GstSharedTaskPoolPrivate *priv;
priv = pool->priv = gst_shared_task_pool_get_instance_private (pool);
priv->max_threads = 1;
}
/**
* gst_shared_task_pool_set_max_threads:
* @pool: a #GstSharedTaskPool
* @max_threads: Maximum number of threads to spawn.
*
* Update the maximal number of threads the @pool may spawn. When
* the maximal number of threads is reduced, existing threads are not
* immediately shut down, see g_thread_pool_set_max_threads().
*
* Setting @max_threads to 0 effectively freezes the pool.
*
* Since: 1.20
*/
void
gst_shared_task_pool_set_max_threads (GstSharedTaskPool * pool,
guint max_threads)
{
GstTaskPool *taskpool;
g_return_if_fail (GST_IS_SHARED_TASK_POOL (pool));
taskpool = GST_TASK_POOL (pool);
GST_OBJECT_LOCK (pool);
if (taskpool->pool)
g_thread_pool_set_max_threads (taskpool->pool, max_threads, NULL);
pool->priv->max_threads = max_threads;
GST_OBJECT_UNLOCK (pool);
}
/**
* gst_shared_task_pool_get_max_threads:
* @pool: a #GstSharedTaskPool
*
* Returns: the maximum number of threads @pool is configured to spawn
* Since: 1.20
*/
guint
gst_shared_task_pool_get_max_threads (GstSharedTaskPool * pool)
{
guint ret;
g_return_val_if_fail (GST_IS_SHARED_TASK_POOL (pool), 0);
GST_OBJECT_LOCK (pool);
ret = pool->priv->max_threads;
GST_OBJECT_UNLOCK (pool);
return ret;
}
/**
* gst_shared_task_pool_new:
*
* Create a new shared task pool. The shared task pool will queue tasks on
* a maximum number of threads, 1 by default.
*
* Do not use a #GstSharedTaskPool to manage potentially inter-dependent tasks such
* as pad tasks, as having one task waiting on another to return before returning
* would cause obvious deadlocks if they happen to share the same thread.
*
* Returns: (transfer full): a new #GstSharedTaskPool. gst_object_unref() after usage.
* Since: 1.20
*/
GstTaskPool *
gst_shared_task_pool_new (void)
{
GstTaskPool *pool;
pool = g_object_new (GST_TYPE_SHARED_TASK_POOL, NULL);
/* clear floating flag */
gst_object_ref_sink (pool);
return pool;
}