ffmpeg/libavformat/async.c

388 lines
11 KiB
C
Raw Normal View History

/*
* Input async protocol.
* Copyright (c) 2015 Zhang Rui <bbcallen@gmail.com>
*
* 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
*
* Based on libavformat/cache.c by Michael Niedermayer
*/
/**
* @TODO
* support timeout
* support backward short seek
* support work with concatdec, hls
*/
#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
#include "libavutil/error.h"
#include "libavutil/fifo.h"
#include "libavutil/log.h"
#include "libavutil/opt.h"
#include "url.h"
#include <stdint.h>
#include <pthread.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#define BUFFER_CAPACITY (4 * 1024 * 1024)
#define SHORT_SEEK_THRESHOLD (256 * 1024)
typedef struct Context {
AVClass *class;
URLContext *inner;
int seek_request;
size_t seek_pos;
int seek_whence;
int seek_completed;
int64_t seek_ret;
int io_error;
int io_eof_reached;
size_t logical_pos;
size_t logical_size;
AVFifoBuffer *fifo;
pthread_cond_t cond_wakeup_main;
pthread_cond_t cond_wakeup_background;
pthread_mutex_t mutex;
pthread_t async_buffer_thread;
int abort_request;
AVIOInterruptCB interrupt_callback;
} Context;
static int async_interrupt_callback(void *arg)
{
URLContext *h = arg;
Context *c = h->priv_data;
int ret = 0;
if (c->interrupt_callback.callback) {
ret = c->interrupt_callback.callback(c->interrupt_callback.opaque);
if (!ret)
return ret;
}
return c->abort_request;
}
static void *async_buffer_task(void *arg)
{
URLContext *h = arg;
Context *c = h->priv_data;
AVFifoBuffer *fifo = c->fifo;
int ret = 0;
while (1) {
int fifo_space, to_copy;
if (async_interrupt_callback(h)) {
c->io_eof_reached = 1;
c->io_error = AVERROR_EXIT;
break;
}
if (c->seek_request) {
pthread_mutex_lock(&c->mutex);
ret = ffurl_seek(c->inner, c->seek_pos, c->seek_whence);
if (ret < 0) {
c->io_eof_reached = 1;
c->io_error = ret;
} else {
c->io_eof_reached = 0;
c->io_error = 0;
}
c->seek_completed = 1;
c->seek_ret = ret;
c->seek_request = 0;
av_fifo_reset(fifo);
pthread_cond_signal(&c->cond_wakeup_main);
pthread_mutex_unlock(&c->mutex);
continue;
}
fifo_space = av_fifo_space(fifo);
if (c->io_eof_reached || fifo_space <= 0) {
pthread_mutex_lock(&c->mutex);
pthread_cond_signal(&c->cond_wakeup_main);
pthread_cond_wait(&c->cond_wakeup_background, &c->mutex);
pthread_mutex_unlock(&c->mutex);
continue;
}
to_copy = FFMIN(4096, fifo_space);
ret = av_fifo_generic_write(fifo, c->inner, to_copy, (void *)ffurl_read);
if (ret <= 0) {
c->io_eof_reached = 1;
if (ret < 0) {
c->io_error = ret;
}
}
pthread_mutex_lock(&c->mutex);
pthread_cond_signal(&c->cond_wakeup_main);
pthread_mutex_unlock(&c->mutex);
}
return NULL;
}
static int async_open(URLContext *h, const char *arg, int flags, AVDictionary **options)
{
Context *c = h->priv_data;
int ret;
AVIOInterruptCB interrupt_callback = {.callback = async_interrupt_callback, .opaque = h};
av_strstart(arg, "async:", &arg);
c->fifo = av_fifo_alloc(BUFFER_CAPACITY);
if (!c->fifo) {
ret = AVERROR(ENOMEM);
goto fifo_fail;
}
/* wrap interrupt callback */
c->interrupt_callback = h->interrupt_callback;
ret = ffurl_open(&c->inner, arg, flags, &interrupt_callback, options);
if (ret != 0) {
av_log(h, AV_LOG_ERROR, "ffurl_open failed : %s, %s\n", strerror(ret), arg);
goto url_fail;
}
c->logical_size = ffurl_size(c->inner);
h->is_streamed = c->inner->is_streamed;
ret = pthread_mutex_init(&c->mutex, NULL);
if (ret != 0) {
av_log(h, AV_LOG_ERROR, "pthread_mutex_init failed : %s\n", strerror(ret));
goto mutex_fail;
}
ret = pthread_cond_init(&c->cond_wakeup_main, NULL);
if (ret != 0) {
av_log(h, AV_LOG_ERROR, "pthread_cond_init failed : %s\n", strerror(ret));
goto cond_wakeup_main_fail;
}
ret = pthread_cond_init(&c->cond_wakeup_background, NULL);
if (ret != 0) {
av_log(h, AV_LOG_ERROR, "pthread_cond_init failed : %s\n", strerror(ret));
goto cond_wakeup_background_fail;
}
ret = pthread_create(&c->async_buffer_thread, NULL, async_buffer_task, h);
if (ret) {
av_log(h, AV_LOG_ERROR, "pthread_create failed : %s\n", strerror(ret));
goto thread_fail;
}
return 0;
thread_fail:
pthread_cond_destroy(&c->cond_wakeup_background);
cond_wakeup_background_fail:
pthread_cond_destroy(&c->cond_wakeup_main);
cond_wakeup_main_fail:
pthread_mutex_destroy(&c->mutex);
mutex_fail:
ffurl_close(c->inner);
url_fail:
av_fifo_freep(&c->fifo);
fifo_fail:
return ret;
}
static int async_close(URLContext *h)
{
Context *c = h->priv_data;
int ret;
pthread_mutex_lock(&c->mutex);
c->abort_request = 1;
pthread_cond_signal(&c->cond_wakeup_background);
pthread_mutex_unlock(&c->mutex);
ret = pthread_join(c->async_buffer_thread, NULL);
if (ret != 0)
av_log(h, AV_LOG_ERROR, "pthread_join(): %s\n", strerror(ret));
pthread_cond_destroy(&c->cond_wakeup_background);
pthread_cond_destroy(&c->cond_wakeup_main);
pthread_mutex_destroy(&c->mutex);
ffurl_close(c->inner);
av_fifo_freep(&c->fifo);
return 0;
}
static int async_read_internal(URLContext *h, void *dest, int size, int read_complete,
void (*func)(void*, void*, int))
{
Context *c = h->priv_data;
AVFifoBuffer *fifo = c->fifo;
int to_read = size;
int ret = 0;
pthread_mutex_lock(&c->mutex);
while (to_read > 0) {
int fifo_size, to_copy;
if (async_interrupt_callback(h)) {
ret = AVERROR_EXIT;
break;
}
fifo_size = av_fifo_size(fifo);
to_copy = FFMIN(to_read, fifo_size);
if (to_copy > 0) {
av_fifo_generic_read(fifo, dest, to_copy, func);
if (!func)
dest = (uint8_t *)dest + to_copy;
c->logical_pos += to_copy;
to_read -= to_copy;
ret = size - to_read;
if (to_read <= 0 || !read_complete)
break;
} else if (c->io_eof_reached) {
if (ret <= 0)
ret = AVERROR_EOF;
break;
}
pthread_cond_signal(&c->cond_wakeup_background);
pthread_cond_wait(&c->cond_wakeup_main, &c->mutex);
}
pthread_cond_signal(&c->cond_wakeup_background);
pthread_mutex_unlock(&c->mutex);
return ret;
}
static int async_read(URLContext *h, unsigned char *buf, int size)
{
return async_read_internal(h, buf, size, 0, NULL);
}
static void fifo_do_not_copy_func(void* dest, void* src, int size) {
// do not copy
}
static int64_t async_seek(URLContext *h, int64_t pos, int whence)
{
Context *c = h->priv_data;
AVFifoBuffer *fifo = c->fifo;
int64_t ret;
int64_t new_logical_pos;
int fifo_size;
if (whence == AVSEEK_SIZE) {
av_log(h, AV_LOG_TRACE, "async_seek: AVSEEK_SIZE: %"PRId64"\n", (int64_t)c->logical_size);
return c->logical_size;
} else if (whence == SEEK_CUR) {
av_log(h, AV_LOG_TRACE, "async_seek: %"PRId64"\n", pos);
new_logical_pos = pos + c->logical_pos;
} else if (whence == SEEK_SET){
av_log(h, AV_LOG_TRACE, "async_seek: %"PRId64"\n", pos);
new_logical_pos = pos;
} else {
return AVERROR(EINVAL);
}
if (new_logical_pos < 0)
return AVERROR(EINVAL);
fifo_size = av_fifo_size(fifo);
if (new_logical_pos == c->logical_pos) {
/* current position */
return c->logical_pos;
} else if ((new_logical_pos > c->logical_pos) &&
(new_logical_pos < (c->logical_pos + fifo_size + SHORT_SEEK_THRESHOLD))) {
/* fast seek */
av_log(h, AV_LOG_TRACE, "async_seek: fask_seek %"PRId64" from %d dist:%d/%d\n",
new_logical_pos, (int)c->logical_pos,
(int)(new_logical_pos - c->logical_pos), fifo_size);
async_read_internal(h, NULL, new_logical_pos - c->logical_pos, 1, fifo_do_not_copy_func);
return c->logical_pos;
} else if (c->logical_size <= 0) {
/* can not seek */
return AVERROR(EINVAL);
} else if (new_logical_pos > c->logical_size) {
/* beyond end */
return AVERROR(EINVAL);
}
pthread_mutex_lock(&c->mutex);
c->seek_request = 1;
c->seek_pos = new_logical_pos;
c->seek_whence = SEEK_SET;
c->seek_completed = 0;
c->seek_ret = 0;
while (1) {
if (async_interrupt_callback(h)) {
ret = AVERROR_EXIT;
break;
}
if (c->seek_completed) {
if (c->seek_ret >= 0)
c->logical_pos = c->seek_ret;
ret = c->seek_ret;
break;
}
pthread_cond_signal(&c->cond_wakeup_background);
pthread_cond_wait(&c->cond_wakeup_main, &c->mutex);
}
pthread_mutex_unlock(&c->mutex);
return ret;
}
#define OFFSET(x) offsetof(Context, x)
#define D AV_OPT_FLAG_DECODING_PARAM
static const AVOption options[] = {
{NULL},
};
static const AVClass async_context_class = {
.class_name = "Async",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
URLProtocol ff_async_protocol = {
.name = "async",
.url_open2 = async_open,
.url_read = async_read,
.url_seek = async_seek,
.url_close = async_close,
.priv_data_size = sizeof(Context),
.priv_data_class = &async_context_class,
};