/*
* 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 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 "libavutil/thread.h"
#include "url.h"
#include <stdint.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#define BUFFER_CAPACITY (4 * 1024 * 1024)
#define READ_BACK_CAPACITY (4 * 1024 * 1024)
#define SHORT_SEEK_THRESHOLD (256 * 1024)
typedef struct RingBuffer
{
AVFifoBuffer *fifo;
int read_back_capacity;
int read_pos;
} RingBuffer;
typedef struct Context {
AVClass *class;
URLContext *inner;
int seek_request;
int64_t seek_pos;
int seek_whence;
int seek_completed;
int64_t seek_ret;
int inner_io_error;
int io_error;
int io_eof_reached;
int64_t logical_pos;
int64_t logical_size;
RingBuffer ring;
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 ring_init(RingBuffer *ring, unsigned int capacity, int read_back_capacity)
{
memset(ring, 0, sizeof(RingBuffer));
ring->fifo = av_fifo_alloc(capacity + read_back_capacity);
if (!ring->fifo)
return AVERROR(ENOMEM);
ring->read_back_capacity = read_back_capacity;
return 0;
}
static void ring_destroy(RingBuffer *ring)
{
av_fifo_freep(&ring->fifo);
}
static void ring_reset(RingBuffer *ring)
{
av_fifo_reset(ring->fifo);
ring->read_pos = 0;
}
static int ring_size(RingBuffer *ring)
{
return av_fifo_size(ring->fifo) - ring->read_pos;
}
static int ring_space(RingBuffer *ring)
{
return av_fifo_space(ring->fifo);
}
static int ring_generic_read(RingBuffer *ring, void *dest, int buf_size, void (*func)(void*, void*, int))
{
int ret;
av_assert2(buf_size <= ring_size(ring));
ret = av_fifo_generic_peek_at(ring->fifo, dest, ring->read_pos, buf_size, func);
ring->read_pos += buf_size;
if (ring->read_pos > ring->read_back_capacity) {
av_fifo_drain(ring->fifo, ring->read_pos - ring->read_back_capacity);
ring->read_pos = ring->read_back_capacity;
}
return ret;
}
static int ring_generic_write(RingBuffer *ring, void *src, int size, int (*func)(void*, void*, int))
{
av_assert2(size <= ring_space(ring));
return av_fifo_generic_write(ring->fifo, src, size, func);
}
static int ring_size_of_read_back(RingBuffer *ring)
{
return ring->read_pos;
}
static int ring_drain(RingBuffer *ring, int offset)
{
av_assert2(offset >= -ring_size_of_read_back(ring));
av_assert2(offset <= -ring_size(ring));
ring->read_pos += offset;
return 0;
}
static int async_check_interrupt(void *arg)
{
URLContext *h = arg;
Context *c = h->priv_data;
if (c->abort_request)
return 1;
if (ff_check_interrupt(&c->interrupt_callback))
c->abort_request = 1;
return c->abort_request;
}
static int wrapped_url_read(void *src, void *dst, int size)
{
URLContext *h = src;
Context *c = h->priv_data;
int ret;
ret = ffurl_read(c->inner, dst, size);
c->inner_io_error = ret < 0 ? ret : 0;
return ret;
}
static void *async_buffer_task(void *arg)
{
URLContext *h = arg;
Context *c = h->priv_data;
RingBuffer *ring = &c->ring;
int ret = 0;
int64_t seek_ret;
while (1) {
int fifo_space, to_copy;
pthread_mutex_lock(&c->mutex);
if (async_check_interrupt(h)) {
c->io_eof_reached = 1;
c->io_error = AVERROR_EXIT;
pthread_cond_signal(&c->cond_wakeup_main);
pthread_mutex_unlock(&c->mutex);
break;
}
if (c->seek_request) {
seek_ret = ffurl_seek(c->inner, c->seek_pos, c->seek_whence);
if (seek_ret >= 0) {
c->io_eof_reached = 0;
c->io_error = 0;
ring_reset(ring);
}
c->seek_completed = 1;
c->seek_ret = seek_ret;
c->seek_request = 0;
pthread_cond_signal(&c->cond_wakeup_main);
pthread_mutex_unlock(&c->mutex);
continue;
}
fifo_space = ring_space(ring);
if (c->io_eof_reached || fifo_space <= 0) {
pthread_cond_signal(&c->cond_wakeup_main);
pthread_cond_wait(&c->cond_wakeup_background, &c->mutex);
pthread_mutex_unlock(&c->mutex);
continue;
}
pthread_mutex_unlock(&c->mutex);
to_copy = FFMIN(4096, fifo_space);
ret = ring_generic_write(ring, (void *)h, to_copy, wrapped_url_read);
pthread_mutex_lock(&c->mutex);
if (ret <= 0) {
c->io_eof_reached = 1;
if (c->inner_io_error < 0)
c->io_error = c->inner_io_error;
}
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_check_interrupt, .opaque = h};
av_strstart(arg, "async:", &arg);
ret = ring_init(&c->ring, BUFFER_CAPACITY, READ_BACK_CAPACITY);
if (ret < 0)
goto fifo_fail;
/* wrap interrupt callback */
c->interrupt_callback = h->interrupt_callback;
ret = ffurl_open_whitelist(&c->inner, arg, flags, &interrupt_callback, options, h->protocol_whitelist, h->protocol_blacklist, h);
if (ret != 0) {
av_log(h, AV_LOG_ERROR, "ffurl_open failed : %s, %s\n", av_err2str(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", av_err2str(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", av_err2str(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", av_err2str(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", av_err2str(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:
ring_destroy(&c->ring);
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", av_err2str(ret));
pthread_cond_destroy(&c->cond_wakeup_background);
pthread_cond_destroy(&c->cond_wakeup_main);
pthread_mutex_destroy(&c->mutex);
ffurl_close(c->inner);
ring_destroy(&c->ring);
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;
RingBuffer *ring = &c->ring;
int to_read = size;
int ret = 0;
pthread_mutex_lock(&c->mutex);
while (to_read > 0) {
int fifo_size, to_copy;
if (async_check_interrupt(h)) {
ret = AVERROR_EXIT;
break;
}
fifo_size = ring_size(ring);
to_copy = FFMIN(to_read, fifo_size);
if (to_copy > 0) {
ring_generic_read(ring, 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) {
if (c->io_error)
ret = c->io_error;
else
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;
RingBuffer *ring = &c->ring;
int64_t ret;
int64_t new_logical_pos;
int fifo_size;
int fifo_size_of_read_back;
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 = ring_size(ring);
fifo_size_of_read_back = ring_size_of_read_back(ring);
if (new_logical_pos == c->logical_pos) {
/* current position */
return c->logical_pos;
} else if ((new_logical_pos >= (c->logical_pos - fifo_size_of_read_back)) &&
(new_logical_pos < (c->logical_pos + fifo_size + SHORT_SEEK_THRESHOLD))) {
int pos_delta = (int)(new_logical_pos - c->logical_pos);
/* 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);
if (pos_delta > 0) {
// fast seek forwards
async_read_internal(h, NULL, pos_delta, 1, fifo_do_not_copy_func);
} else {
// fast seek backwards
ring_drain(ring, pos_delta);
c->logical_pos = new_logical_pos;
}
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_check_interrupt(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},
};
#undef D
#undef OFFSET
static const AVClass async_context_class = {
.class_name = "Async",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
const 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,
};
#if 0
#define TEST_SEEK_POS (1536)
#define TEST_STREAM_SIZE (2048)
typedef struct TestContext {
AVClass *class;
int64_t logical_pos;
int64_t logical_size;
/* options */
int opt_read_error;
} TestContext;
static int async_test_open(URLContext *h, const char *arg, int flags, AVDictionary **options)
{
TestContext *c = h->priv_data;
c->logical_pos = 0;
c->logical_size = TEST_STREAM_SIZE;
return 0;
}
static int async_test_close(URLContext *h)
{
return 0;
}
static int async_test_read(URLContext *h, unsigned char *buf, int size)
{
TestContext *c = h->priv_data;
int i;
int read_len = 0;
if (c->opt_read_error)
return c->opt_read_error;
if (c->logical_pos >= c->logical_size)
return AVERROR_EOF;
for (i = 0; i < size; ++i) {
buf[i] = c->logical_pos & 0xFF;
c->logical_pos++;
read_len++;
if (c->logical_pos >= c->logical_size)
break;
}
return read_len;
}
static int64_t async_test_seek(URLContext *h, int64_t pos, int whence)
{
TestContext *c = h->priv_data;
int64_t new_logical_pos;
if (whence == AVSEEK_SIZE) {
return c->logical_size;
} else if (whence == SEEK_CUR) {
new_logical_pos = pos + c->logical_pos;
} else if (whence == SEEK_SET){
new_logical_pos = pos;
} else {
return AVERROR(EINVAL);
}
if (new_logical_pos < 0)
return AVERROR(EINVAL);
c->logical_pos = new_logical_pos;
return new_logical_pos;
}
#define OFFSET(x) offsetof(TestContext, x)
#define D AV_OPT_FLAG_DECODING_PARAM
static const AVOption async_test_options[] = {
{ "async-test-read-error", "cause read fail",
OFFSET(opt_read_error), AV_OPT_TYPE_INT, { .i64 = 0 }, INT_MIN, INT_MAX, .flags = D },
{NULL},
};
#undef D
#undef OFFSET
static const AVClass async_test_context_class = {
.class_name = "Async-Test",
.item_name = av_default_item_name,
.option = async_test_options,
.version = LIBAVUTIL_VERSION_INT,
};
const URLProtocol ff_async_test_protocol = {
.name = "async-test",
.url_open2 = async_test_open,
.url_read = async_test_read,
.url_seek = async_test_seek,
.url_close = async_test_close,
.priv_data_size = sizeof(TestContext),
.priv_data_class = &async_test_context_class,
};
int main(void)
{
URLContext *h = NULL;
int i;
int ret;
int64_t size;
int64_t pos;
int64_t read_len;
unsigned char buf[4096];
AVDictionary *opts = NULL;
ffurl_register_protocol(&ff_async_protocol);
ffurl_register_protocol(&ff_async_test_protocol);
/*
* test normal read
*/
ret = ffurl_open(&h, "async:async-test:", AVIO_FLAG_READ, NULL, NULL);
printf("open: %d\n", ret);
size = ffurl_size(h);
printf("size: %"PRId64"\n", size);
pos = ffurl_seek(h, 0, SEEK_CUR);
read_len = 0;
while (1) {
ret = ffurl_read(h, buf, sizeof(buf));
if (ret == AVERROR_EOF) {
printf("read-error: AVERROR_EOF at %"PRId64"\n", ffurl_seek(h, 0, SEEK_CUR));
break;
}
else if (ret == 0)
break;
else if (ret < 0) {
printf("read-error: %d at %"PRId64"\n", ret, ffurl_seek(h, 0, SEEK_CUR));
goto fail;
} else {
for (i = 0; i < ret; ++i) {
if (buf[i] != (pos & 0xFF)) {
printf("read-mismatch: actual %d, expecting %d, at %"PRId64"\n",
(int)buf[i], (int)(pos & 0xFF), pos);
break;
}
pos++;
}
}
read_len += ret;
}
printf("read: %"PRId64"\n", read_len);
/*
* test normal seek
*/
ret = ffurl_read(h, buf, 1);
printf("read: %d\n", ret);
pos = ffurl_seek(h, TEST_SEEK_POS, SEEK_SET);
printf("seek: %"PRId64"\n", pos);
read_len = 0;
while (1) {
ret = ffurl_read(h, buf, sizeof(buf));
if (ret == AVERROR_EOF)
break;
else if (ret == 0)
break;
else if (ret < 0) {
printf("read-error: %d at %"PRId64"\n", ret, ffurl_seek(h, 0, SEEK_CUR));
goto fail;
} else {
for (i = 0; i < ret; ++i) {
if (buf[i] != (pos & 0xFF)) {
printf("read-mismatch: actual %d, expecting %d, at %"PRId64"\n",
(int)buf[i], (int)(pos & 0xFF), pos);
break;
}
pos++;
}
}
read_len += ret;
}
printf("read: %"PRId64"\n", read_len);
ret = ffurl_read(h, buf, 1);
printf("read: %d\n", ret);
/*
* test read error
*/
ffurl_close(h);
av_dict_set_int(&opts, "async-test-read-error", -10000, 0);
ret = ffurl_open(&h, "async:async-test:", AVIO_FLAG_READ, NULL, &opts);
printf("open: %d\n", ret);
ret = ffurl_read(h, buf, 1);
printf("read: %d\n", ret);
fail:
av_dict_free(&opts);
ffurl_close(h);
return 0;
}
#endif