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FFmpeg/libavutil/executor.h
Zhao Zhili baf3123c1c avutil/executor: Allowing thread_count be zero
Before the patch, disable threads support at configure/build time
was the only method to force zero thread in executor. However,
it's common practice for libavcodec to run on caller's thread when
user specify thread number to one. And for WASM environment, whether
threads are supported needs to be detected at runtime. So executor
should support zero thread at runtime.

A single thread executor can be useful, e.g., to handle network
protocol. So we can't take thread_count one as zero thread, which
disabled a valid usercase.

Other libraries take -threads 0 to mean auto. Executor as a low
level utils doesn't do cpu detect. So take thread_count zero as
zero thread, literally.

Signed-off-by: Zhao Zhili <zhilizhao@tencent.com>
2024-06-27 20:54:42 +08:00

68 lines
1.9 KiB
C

/*
* Copyright (C) 2023 Nuo Mi
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVUTIL_EXECUTOR_H
#define AVUTIL_EXECUTOR_H
typedef struct AVExecutor AVExecutor;
typedef struct AVTask AVTask;
struct AVTask {
AVTask *next;
};
typedef struct AVTaskCallbacks {
void *user_data;
int local_context_size;
// return 1 if a's priority > b's priority
int (*priority_higher)(const AVTask *a, const AVTask *b);
// task is ready for run
int (*ready)(const AVTask *t, void *user_data);
// run the task
int (*run)(AVTask *t, void *local_context, void *user_data);
} AVTaskCallbacks;
/**
* Alloc executor
* @param callbacks callback structure for executor
* @param thread_count worker thread number, 0 for run on caller's thread directly
* @return return the executor
*/
AVExecutor* av_executor_alloc(const AVTaskCallbacks *callbacks, int thread_count);
/**
* Free executor
* @param e pointer to executor
*/
void av_executor_free(AVExecutor **e);
/**
* Add task to executor
* @param e pointer to executor
* @param t pointer to task. If NULL, it will wakeup one work thread
*/
void av_executor_execute(AVExecutor *e, AVTask *t);
#endif //AVUTIL_EXECUTOR_H