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856 lines
22 KiB
C
856 lines
22 KiB
C
/* GStreamer
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* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
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* 2005 Wim Taymans <wim@fluendo.com>
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*
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* gsttask.c: Streaming tasks
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*/
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/**
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* SECTION:gsttask
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* @title: GstTask
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* @short_description: Abstraction of GStreamer streaming threads.
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* @see_also: #GstElement, #GstPad
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*
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* #GstTask is used by #GstElement and #GstPad to provide the data passing
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* threads in a #GstPipeline.
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*
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* A #GstPad will typically start a #GstTask to push or pull data to/from the
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* peer pads. Most source elements start a #GstTask to push data. In some cases
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* a demuxer element can start a #GstTask to pull data from a peer element. This
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* is typically done when the demuxer can perform random access on the upstream
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* peer element for improved performance.
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*
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* Although convenience functions exist on #GstPad to start/pause/stop tasks, it
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* might sometimes be needed to create a #GstTask manually if it is not related to
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* a #GstPad.
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*
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* Before the #GstTask can be run, it needs a #GRecMutex that can be set with
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* gst_task_set_lock().
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*
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* The task can be started, paused and stopped with gst_task_start(), gst_task_pause()
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* and gst_task_stop() respectively or with the gst_task_set_state() function.
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*
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* A #GstTask will repeatedly call the #GstTaskFunction with the user data
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* that was provided when creating the task with gst_task_new(). While calling
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* the function it will acquire the provided lock. The provided lock is released
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* when the task pauses or stops.
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*
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* Stopping a task with gst_task_stop() will not immediately make sure the task is
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* not running anymore. Use gst_task_join() to make sure the task is completely
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* stopped and the thread is stopped.
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*
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* After creating a #GstTask, use gst_object_unref() to free its resources. This can
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* only be done when the task is not running anymore.
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*
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* Task functions can send a #GstMessage to send out-of-band data to the
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* application. The application can receive messages from the #GstBus in its
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* mainloop.
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*
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* For debugging purposes, the task will configure its object name as the thread
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* name on Linux. Please note that the object name should be configured before the
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* task is started; changing the object name after the task has been started, has
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* no effect on the thread name.
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*/
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#include "gst_private.h"
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#include "gstinfo.h"
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#include "gsttask.h"
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#include "glib-compat-private.h"
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#include <stdio.h>
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#ifdef HAVE_SYS_PRCTL_H
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#include <sys/prctl.h>
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#endif
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#ifdef HAVE_PTHREAD_SETNAME_NP_WITHOUT_TID
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#include <pthread.h>
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#endif
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GST_DEBUG_CATEGORY_STATIC (task_debug);
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#define GST_CAT_DEFAULT (task_debug)
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#define SET_TASK_STATE(t,s) (g_atomic_int_set (&GST_TASK_STATE(t), (s)))
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#define GET_TASK_STATE(t) ((GstTaskState) g_atomic_int_get (&GST_TASK_STATE(t)))
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struct _GstTaskPrivate
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{
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/* callbacks for managing the thread of this task */
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GstTaskThreadFunc enter_func;
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gpointer enter_user_data;
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GDestroyNotify enter_notify;
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GstTaskThreadFunc leave_func;
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gpointer leave_user_data;
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GDestroyNotify leave_notify;
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/* configured pool */
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GstTaskPool *pool;
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/* remember the pool and id that is currently running. */
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gpointer id;
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GstTaskPool *pool_id;
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};
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#ifdef _MSC_VER
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#define WIN32_LEAN_AND_MEAN
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#include <windows.h>
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struct _THREADNAME_INFO
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{
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DWORD dwType; // must be 0x1000
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LPCSTR szName; // pointer to name (in user addr space)
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DWORD dwThreadID; // thread ID (-1=caller thread)
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DWORD dwFlags; // reserved for future use, must be zero
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};
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typedef struct _THREADNAME_INFO THREADNAME_INFO;
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void
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SetThreadName (DWORD dwThreadID, LPCSTR szThreadName)
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{
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THREADNAME_INFO info;
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info.dwType = 0x1000;
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info.szName = szThreadName;
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info.dwThreadID = dwThreadID;
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info.dwFlags = 0;
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__try {
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RaiseException (0x406D1388, 0, sizeof (info) / sizeof (DWORD),
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(const ULONG_PTR *) &info);
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}
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__except (EXCEPTION_CONTINUE_EXECUTION) {
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}
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}
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#endif
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static void gst_task_finalize (GObject * object);
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static void gst_task_func (GstTask * task);
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static GMutex pool_lock;
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#define _do_init \
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{ \
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GST_DEBUG_CATEGORY_INIT (task_debug, "task", 0, "Processing tasks"); \
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}
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G_DEFINE_TYPE_WITH_CODE (GstTask, gst_task, GST_TYPE_OBJECT,
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G_ADD_PRIVATE (GstTask) _do_init);
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static void
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init_klass_pool (GstTaskClass * klass)
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{
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g_mutex_lock (&pool_lock);
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if (klass->pool) {
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gst_task_pool_cleanup (klass->pool);
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gst_object_unref (klass->pool);
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}
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klass->pool = gst_task_pool_new ();
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/* Classes are never destroyed so this ref will never be dropped */
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GST_OBJECT_FLAG_SET (klass->pool, GST_OBJECT_FLAG_MAY_BE_LEAKED);
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gst_task_pool_prepare (klass->pool, NULL);
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g_mutex_unlock (&pool_lock);
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}
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static void
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gst_task_class_init (GstTaskClass * klass)
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{
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GObjectClass *gobject_class;
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gobject_class = (GObjectClass *) klass;
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gobject_class->finalize = gst_task_finalize;
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init_klass_pool (klass);
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}
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static void
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gst_task_init (GstTask * task)
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{
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GstTaskClass *klass;
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klass = GST_TASK_GET_CLASS (task);
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task->priv = gst_task_get_instance_private (task);
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task->running = FALSE;
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task->thread = NULL;
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task->lock = NULL;
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g_cond_init (&task->cond);
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SET_TASK_STATE (task, GST_TASK_STOPPED);
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/* use the default klass pool for this task, users can
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* override this later */
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g_mutex_lock (&pool_lock);
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task->priv->pool = gst_object_ref (klass->pool);
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g_mutex_unlock (&pool_lock);
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}
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static void
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gst_task_finalize (GObject * object)
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{
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GstTask *task = GST_TASK (object);
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GstTaskPrivate *priv = task->priv;
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GST_DEBUG ("task %p finalize", task);
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if (priv->enter_notify)
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priv->enter_notify (priv->enter_user_data);
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if (priv->leave_notify)
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priv->leave_notify (priv->leave_user_data);
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if (task->notify)
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task->notify (task->user_data);
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gst_object_unref (priv->pool);
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/* task thread cannot be running here since it holds a ref
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* to the task so that the finalize could not have happened */
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g_cond_clear (&task->cond);
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G_OBJECT_CLASS (gst_task_parent_class)->finalize (object);
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}
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/* should be called with the object LOCK */
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static void
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gst_task_configure_name (GstTask * task)
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{
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#if defined(HAVE_SYS_PRCTL_H) && defined(PR_SET_NAME)
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const gchar *name;
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gchar thread_name[17] = { 0, };
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GST_OBJECT_LOCK (task);
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name = GST_OBJECT_NAME (task);
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/* set the thread name to something easily identifiable */
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if (!snprintf (thread_name, 17, "%s", GST_STR_NULL (name))) {
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GST_DEBUG_OBJECT (task, "Could not create thread name for '%s'", name);
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} else {
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GST_DEBUG_OBJECT (task, "Setting thread name to '%s'", thread_name);
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if (prctl (PR_SET_NAME, (unsigned long int) thread_name, 0, 0, 0))
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GST_DEBUG_OBJECT (task, "Failed to set thread name");
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}
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GST_OBJECT_UNLOCK (task);
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#elif defined(HAVE_PTHREAD_SETNAME_NP_WITHOUT_TID)
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const gchar *name;
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GST_OBJECT_LOCK (task);
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name = GST_OBJECT_NAME (task);
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/* set the thread name to something easily identifiable */
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GST_DEBUG_OBJECT (task, "Setting thread name to '%s'", name);
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if (pthread_setname_np (name))
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GST_DEBUG_OBJECT (task, "Failed to set thread name");
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GST_OBJECT_UNLOCK (task);
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#elif defined (_MSC_VER)
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const gchar *name;
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name = GST_OBJECT_NAME (task);
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/* set the thread name to something easily identifiable */
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GST_DEBUG_OBJECT (task, "Setting thread name to '%s'", name);
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SetThreadName (-1, name);
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#endif
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}
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static void
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gst_task_func (GstTask * task)
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{
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GRecMutex *lock;
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GThread *tself;
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GstTaskPrivate *priv;
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priv = task->priv;
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tself = g_thread_self ();
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GST_DEBUG ("Entering task %p, thread %p", task, tself);
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/* we have to grab the lock to get the mutex. We also
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* mark our state running so that nobody can mess with
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* the mutex. */
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GST_OBJECT_LOCK (task);
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if (GET_TASK_STATE (task) == GST_TASK_STOPPED)
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goto exit;
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lock = GST_TASK_GET_LOCK (task);
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if (G_UNLIKELY (lock == NULL))
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goto no_lock;
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task->thread = tself;
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GST_OBJECT_UNLOCK (task);
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/* fire the enter_func callback when we need to */
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if (priv->enter_func)
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priv->enter_func (task, tself, priv->enter_user_data);
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/* locking order is TASK_LOCK, LOCK */
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g_rec_mutex_lock (lock);
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/* configure the thread name now */
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gst_task_configure_name (task);
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while (G_LIKELY (GET_TASK_STATE (task) != GST_TASK_STOPPED)) {
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GST_OBJECT_LOCK (task);
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while (G_UNLIKELY (GST_TASK_STATE (task) == GST_TASK_PAUSED)) {
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g_rec_mutex_unlock (lock);
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GST_TASK_SIGNAL (task);
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GST_INFO_OBJECT (task, "Task going to paused");
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GST_TASK_WAIT (task);
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GST_INFO_OBJECT (task, "Task resume from paused");
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GST_OBJECT_UNLOCK (task);
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/* locking order.. */
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g_rec_mutex_lock (lock);
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GST_OBJECT_LOCK (task);
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}
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if (G_UNLIKELY (GET_TASK_STATE (task) == GST_TASK_STOPPED)) {
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GST_OBJECT_UNLOCK (task);
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break;
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} else {
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GST_OBJECT_UNLOCK (task);
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}
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task->func (task->user_data);
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}
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g_rec_mutex_unlock (lock);
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GST_OBJECT_LOCK (task);
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task->thread = NULL;
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exit:
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if (priv->leave_func) {
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/* fire the leave_func callback when we need to. We need to do this before
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* we signal the task and with the task lock released. */
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GST_OBJECT_UNLOCK (task);
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priv->leave_func (task, tself, priv->leave_user_data);
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GST_OBJECT_LOCK (task);
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}
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/* now we allow messing with the lock again by setting the running flag to
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* %FALSE. Together with the SIGNAL this is the sign for the _join() to
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* complete.
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* Note that we still have not dropped the final ref on the task. We could
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* check here if there is a pending join() going on and drop the last ref
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* before releasing the lock as we can be sure that a ref is held by the
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* caller of the join(). */
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task->running = FALSE;
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GST_TASK_SIGNAL (task);
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GST_OBJECT_UNLOCK (task);
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GST_DEBUG ("Exit task %p, thread %p", task, g_thread_self ());
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gst_object_unref (task);
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return;
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no_lock:
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{
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g_warning ("starting task without a lock");
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goto exit;
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}
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}
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/**
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* gst_task_cleanup_all:
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*
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* Wait for all tasks to be stopped. This is mainly used internally
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* to ensure proper cleanup of internal data structures in test suites.
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*
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* MT safe.
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*/
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void
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gst_task_cleanup_all (void)
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{
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GstTaskClass *klass;
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if ((klass = g_type_class_peek (GST_TYPE_TASK))) {
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init_klass_pool (klass);
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}
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/* GstElement owns a GThreadPool */
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_priv_gst_element_cleanup ();
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}
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/**
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* gst_task_new:
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* @func: The #GstTaskFunction to use
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* @user_data: User data to pass to @func
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* @notify: the function to call when @user_data is no longer needed.
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*
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* Create a new Task that will repeatedly call the provided @func
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* with @user_data as a parameter. Typically the task will run in
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* a new thread.
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*
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* The function cannot be changed after the task has been created. You
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* must create a new #GstTask to change the function.
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*
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* This function will not yet create and start a thread. Use gst_task_start() or
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* gst_task_pause() to create and start the GThread.
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*
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* Before the task can be used, a #GRecMutex must be configured using the
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* gst_task_set_lock() function. This lock will always be acquired while
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* @func is called.
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*
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* Returns: (transfer full): A new #GstTask.
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*
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* MT safe.
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*/
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GstTask *
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gst_task_new (GstTaskFunction func, gpointer user_data, GDestroyNotify notify)
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{
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GstTask *task;
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g_return_val_if_fail (func != NULL, NULL);
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task = g_object_new (GST_TYPE_TASK, NULL);
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task->func = func;
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task->user_data = user_data;
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task->notify = notify;
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GST_DEBUG ("Created task %p", task);
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/* clear floating flag */
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gst_object_ref_sink (task);
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return task;
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}
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/**
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* gst_task_set_lock:
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* @task: The #GstTask to use
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* @mutex: The #GRecMutex to use
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*
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* Set the mutex used by the task. The mutex will be acquired before
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* calling the #GstTaskFunction.
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*
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* This function has to be called before calling gst_task_pause() or
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* gst_task_start().
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*
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* MT safe.
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*/
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void
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gst_task_set_lock (GstTask * task, GRecMutex * mutex)
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{
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g_return_if_fail (GST_IS_TASK (task));
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GST_OBJECT_LOCK (task);
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if (G_UNLIKELY (task->running))
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goto is_running;
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GST_INFO ("setting stream lock %p on task %p", mutex, task);
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GST_TASK_GET_LOCK (task) = mutex;
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GST_OBJECT_UNLOCK (task);
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return;
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/* ERRORS */
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is_running:
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{
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GST_OBJECT_UNLOCK (task);
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g_warning ("cannot call set_lock on a running task");
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}
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}
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/**
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* gst_task_get_pool:
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* @task: a #GstTask
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*
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* Get the #GstTaskPool that this task will use for its streaming
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* threads.
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*
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* MT safe.
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*
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* Returns: (transfer full): the #GstTaskPool used by @task. gst_object_unref()
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* after usage.
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*/
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GstTaskPool *
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gst_task_get_pool (GstTask * task)
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{
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GstTaskPool *result;
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GstTaskPrivate *priv;
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g_return_val_if_fail (GST_IS_TASK (task), NULL);
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priv = task->priv;
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GST_OBJECT_LOCK (task);
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result = gst_object_ref (priv->pool);
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GST_OBJECT_UNLOCK (task);
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return result;
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}
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/**
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* gst_task_set_pool:
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* @task: a #GstTask
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* @pool: (transfer none): a #GstTaskPool
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*
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* Set @pool as the new GstTaskPool for @task. Any new streaming threads that
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* will be created by @task will now use @pool.
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*
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* MT safe.
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*/
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void
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gst_task_set_pool (GstTask * task, GstTaskPool * pool)
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{
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GstTaskPool *old;
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GstTaskPrivate *priv;
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g_return_if_fail (GST_IS_TASK (task));
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g_return_if_fail (GST_IS_TASK_POOL (pool));
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priv = task->priv;
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|
|
GST_OBJECT_LOCK (task);
|
|
if (priv->pool != pool) {
|
|
old = priv->pool;
|
|
priv->pool = gst_object_ref (pool);
|
|
} else
|
|
old = NULL;
|
|
GST_OBJECT_UNLOCK (task);
|
|
|
|
if (old)
|
|
gst_object_unref (old);
|
|
}
|
|
|
|
/**
|
|
* gst_task_set_enter_callback:
|
|
* @task: The #GstTask to use
|
|
* @enter_func: (in): a #GstTaskThreadFunc
|
|
* @user_data: user data passed to @enter_func
|
|
* @notify: called when @user_data is no longer referenced
|
|
*
|
|
* Call @enter_func when the task function of @task is entered. @user_data will
|
|
* be passed to @enter_func and @notify will be called when @user_data is no
|
|
* longer referenced.
|
|
*/
|
|
void
|
|
gst_task_set_enter_callback (GstTask * task, GstTaskThreadFunc enter_func,
|
|
gpointer user_data, GDestroyNotify notify)
|
|
{
|
|
GDestroyNotify old_notify;
|
|
|
|
g_return_if_fail (task != NULL);
|
|
g_return_if_fail (GST_IS_TASK (task));
|
|
|
|
GST_OBJECT_LOCK (task);
|
|
if ((old_notify = task->priv->enter_notify)) {
|
|
gpointer old_data = task->priv->enter_user_data;
|
|
|
|
task->priv->enter_user_data = NULL;
|
|
task->priv->enter_notify = NULL;
|
|
GST_OBJECT_UNLOCK (task);
|
|
|
|
old_notify (old_data);
|
|
|
|
GST_OBJECT_LOCK (task);
|
|
}
|
|
task->priv->enter_func = enter_func;
|
|
task->priv->enter_user_data = user_data;
|
|
task->priv->enter_notify = notify;
|
|
GST_OBJECT_UNLOCK (task);
|
|
}
|
|
|
|
/**
|
|
* gst_task_set_leave_callback:
|
|
* @task: The #GstTask to use
|
|
* @leave_func: (in): a #GstTaskThreadFunc
|
|
* @user_data: user data passed to @leave_func
|
|
* @notify: called when @user_data is no longer referenced
|
|
*
|
|
* Call @leave_func when the task function of @task is left. @user_data will
|
|
* be passed to @leave_func and @notify will be called when @user_data is no
|
|
* longer referenced.
|
|
*/
|
|
void
|
|
gst_task_set_leave_callback (GstTask * task, GstTaskThreadFunc leave_func,
|
|
gpointer user_data, GDestroyNotify notify)
|
|
{
|
|
GDestroyNotify old_notify;
|
|
|
|
g_return_if_fail (task != NULL);
|
|
g_return_if_fail (GST_IS_TASK (task));
|
|
|
|
GST_OBJECT_LOCK (task);
|
|
if ((old_notify = task->priv->leave_notify)) {
|
|
gpointer old_data = task->priv->leave_user_data;
|
|
|
|
task->priv->leave_user_data = NULL;
|
|
task->priv->leave_notify = NULL;
|
|
GST_OBJECT_UNLOCK (task);
|
|
|
|
old_notify (old_data);
|
|
|
|
GST_OBJECT_LOCK (task);
|
|
}
|
|
task->priv->leave_func = leave_func;
|
|
task->priv->leave_user_data = user_data;
|
|
task->priv->leave_notify = notify;
|
|
GST_OBJECT_UNLOCK (task);
|
|
}
|
|
|
|
/**
|
|
* gst_task_get_state:
|
|
* @task: The #GstTask to query
|
|
*
|
|
* Get the current state of the task.
|
|
*
|
|
* Returns: The #GstTaskState of the task
|
|
*
|
|
* MT safe.
|
|
*/
|
|
GstTaskState
|
|
gst_task_get_state (GstTask * task)
|
|
{
|
|
GstTaskState result;
|
|
|
|
g_return_val_if_fail (GST_IS_TASK (task), GST_TASK_STOPPED);
|
|
|
|
result = GET_TASK_STATE (task);
|
|
|
|
return result;
|
|
}
|
|
|
|
/* make sure the task is running and start a thread if it's not.
|
|
* This function must be called with the task LOCK. */
|
|
static gboolean
|
|
start_task (GstTask * task)
|
|
{
|
|
gboolean res = TRUE;
|
|
GError *error = NULL;
|
|
GstTaskPrivate *priv;
|
|
|
|
priv = task->priv;
|
|
|
|
/* new task, We ref before so that it remains alive while
|
|
* the thread is running. */
|
|
gst_object_ref (task);
|
|
/* mark task as running so that a join will wait until we schedule
|
|
* and exit the task function. */
|
|
task->running = TRUE;
|
|
|
|
/* push on the thread pool, we remember the original pool because the user
|
|
* could change it later on and then we join to the wrong pool. */
|
|
priv->pool_id = gst_object_ref (priv->pool);
|
|
priv->id =
|
|
gst_task_pool_push (priv->pool_id, (GstTaskPoolFunction) gst_task_func,
|
|
task, &error);
|
|
|
|
if (error != NULL) {
|
|
g_warning ("failed to create thread: %s", error->message);
|
|
g_error_free (error);
|
|
res = FALSE;
|
|
}
|
|
return res;
|
|
}
|
|
|
|
|
|
/**
|
|
* gst_task_set_state:
|
|
* @task: a #GstTask
|
|
* @state: the new task state
|
|
*
|
|
* Sets the state of @task to @state.
|
|
*
|
|
* The @task must have a lock associated with it using
|
|
* gst_task_set_lock() when going to GST_TASK_STARTED or GST_TASK_PAUSED or
|
|
* this function will return %FALSE.
|
|
*
|
|
* MT safe.
|
|
*
|
|
* Returns: %TRUE if the state could be changed.
|
|
*/
|
|
gboolean
|
|
gst_task_set_state (GstTask * task, GstTaskState state)
|
|
{
|
|
GstTaskState old;
|
|
gboolean res = TRUE;
|
|
|
|
g_return_val_if_fail (GST_IS_TASK (task), FALSE);
|
|
|
|
GST_DEBUG_OBJECT (task, "Changing task %p to state %d", task, state);
|
|
|
|
GST_OBJECT_LOCK (task);
|
|
if (state != GST_TASK_STOPPED)
|
|
if (G_UNLIKELY (GST_TASK_GET_LOCK (task) == NULL))
|
|
goto no_lock;
|
|
|
|
/* if the state changed, do our thing */
|
|
old = GET_TASK_STATE (task);
|
|
if (old != state) {
|
|
SET_TASK_STATE (task, state);
|
|
switch (old) {
|
|
case GST_TASK_STOPPED:
|
|
/* If the task already has a thread scheduled we don't have to do
|
|
* anything. */
|
|
if (G_UNLIKELY (!task->running))
|
|
res = start_task (task);
|
|
break;
|
|
case GST_TASK_PAUSED:
|
|
/* when we are paused, signal to go to the new state */
|
|
GST_TASK_SIGNAL (task);
|
|
break;
|
|
case GST_TASK_STARTED:
|
|
/* if we were started, we'll go to the new state after the next
|
|
* iteration. */
|
|
break;
|
|
}
|
|
}
|
|
GST_OBJECT_UNLOCK (task);
|
|
|
|
return res;
|
|
|
|
/* ERRORS */
|
|
no_lock:
|
|
{
|
|
GST_WARNING_OBJECT (task, "state %d set on task without a lock", state);
|
|
GST_OBJECT_UNLOCK (task);
|
|
g_warning ("task without a lock can't be set to state %d", state);
|
|
return FALSE;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* gst_task_start:
|
|
* @task: The #GstTask to start
|
|
*
|
|
* Starts @task. The @task must have a lock associated with it using
|
|
* gst_task_set_lock() or this function will return %FALSE.
|
|
*
|
|
* Returns: %TRUE if the task could be started.
|
|
*
|
|
* MT safe.
|
|
*/
|
|
gboolean
|
|
gst_task_start (GstTask * task)
|
|
{
|
|
return gst_task_set_state (task, GST_TASK_STARTED);
|
|
}
|
|
|
|
/**
|
|
* gst_task_stop:
|
|
* @task: The #GstTask to stop
|
|
*
|
|
* Stops @task. This method merely schedules the task to stop and
|
|
* will not wait for the task to have completely stopped. Use
|
|
* gst_task_join() to stop and wait for completion.
|
|
*
|
|
* Returns: %TRUE if the task could be stopped.
|
|
*
|
|
* MT safe.
|
|
*/
|
|
gboolean
|
|
gst_task_stop (GstTask * task)
|
|
{
|
|
return gst_task_set_state (task, GST_TASK_STOPPED);
|
|
}
|
|
|
|
/**
|
|
* gst_task_pause:
|
|
* @task: The #GstTask to pause
|
|
*
|
|
* Pauses @task. This method can also be called on a task in the
|
|
* stopped state, in which case a thread will be started and will remain
|
|
* in the paused state. This function does not wait for the task to complete
|
|
* the paused state.
|
|
*
|
|
* Returns: %TRUE if the task could be paused.
|
|
*
|
|
* MT safe.
|
|
*/
|
|
gboolean
|
|
gst_task_pause (GstTask * task)
|
|
{
|
|
return gst_task_set_state (task, GST_TASK_PAUSED);
|
|
}
|
|
|
|
/**
|
|
* gst_task_join:
|
|
* @task: The #GstTask to join
|
|
*
|
|
* Joins @task. After this call, it is safe to unref the task
|
|
* and clean up the lock set with gst_task_set_lock().
|
|
*
|
|
* The task will automatically be stopped with this call.
|
|
*
|
|
* This function cannot be called from within a task function as this
|
|
* would cause a deadlock. The function will detect this and print a
|
|
* g_warning.
|
|
*
|
|
* Returns: %TRUE if the task could be joined.
|
|
*
|
|
* MT safe.
|
|
*/
|
|
gboolean
|
|
gst_task_join (GstTask * task)
|
|
{
|
|
GThread *tself;
|
|
GstTaskPrivate *priv;
|
|
gpointer id;
|
|
GstTaskPool *pool = NULL;
|
|
|
|
g_return_val_if_fail (GST_IS_TASK (task), FALSE);
|
|
|
|
priv = task->priv;
|
|
|
|
tself = g_thread_self ();
|
|
|
|
GST_DEBUG_OBJECT (task, "Joining task %p, thread %p", task, tself);
|
|
|
|
/* we don't use a real thread join here because we are using
|
|
* thread pools */
|
|
GST_OBJECT_LOCK (task);
|
|
if (G_UNLIKELY (tself == task->thread))
|
|
goto joining_self;
|
|
SET_TASK_STATE (task, GST_TASK_STOPPED);
|
|
/* signal the state change for when it was blocked in PAUSED. */
|
|
GST_TASK_SIGNAL (task);
|
|
/* we set the running flag when pushing the task on the thread pool.
|
|
* This means that the task function might not be called when we try
|
|
* to join it here. */
|
|
while (G_LIKELY (task->running))
|
|
GST_TASK_WAIT (task);
|
|
/* clean the thread */
|
|
task->thread = NULL;
|
|
/* get the id and pool to join */
|
|
pool = priv->pool_id;
|
|
id = priv->id;
|
|
priv->pool_id = NULL;
|
|
priv->id = NULL;
|
|
GST_OBJECT_UNLOCK (task);
|
|
|
|
if (pool) {
|
|
if (id)
|
|
gst_task_pool_join (pool, id);
|
|
gst_object_unref (pool);
|
|
}
|
|
|
|
GST_DEBUG_OBJECT (task, "Joined task %p", task);
|
|
|
|
return TRUE;
|
|
|
|
/* ERRORS */
|
|
joining_self:
|
|
{
|
|
GST_WARNING_OBJECT (task, "trying to join task from its thread");
|
|
GST_OBJECT_UNLOCK (task);
|
|
g_warning ("\nTrying to join task %p from its thread would deadlock.\n"
|
|
"You cannot change the state of an element from its streaming\n"
|
|
"thread. Use g_idle_add() or post a GstMessage on the bus to\n"
|
|
"schedule the state change from the main thread.\n", task);
|
|
return FALSE;
|
|
}
|
|
}
|