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/*
* ZeroMQ Protocol
* Copyright (c) 2019 Andriy Gelman
*
* 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
*/
#include <zmq.h>
#include "url.h"
#include "network.h"
#include "libavutil/avstring.h"
#include "libavutil/opt.h"
#include "libavutil/time.h"
#define ZMQ_STRERROR zmq_strerror(zmq_errno())
typedef struct ZMQContext {
const AVClass *class;
void *context;
void *socket;
int pkt_size;
int pkt_size_overflow; /*keep track of the largest packet during overflow*/
} ZMQContext;
#define OFFSET(x) offsetof(ZMQContext, x)
#define D AV_OPT_FLAG_DECODING_PARAM
#define E AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
{ "pkt_size", "Maximum send/read packet size", OFFSET(pkt_size), AV_OPT_TYPE_INT, { .i64 = 131072 }, -1, INT_MAX, .flags = D | E },
{ NULL }
};
static int zmq_proto_wait(URLContext *h, void *socket, int write)
{
int ret;
int ev = write ? ZMQ_POLLOUT : ZMQ_POLLIN;
zmq_pollitem_t items = { .socket = socket, .fd = 0, .events = ev, .revents = 0 };
ret = zmq_poll(&items, 1, POLLING_TIME);
if (ret == -1) {
av_log(h, AV_LOG_ERROR, "Error occurred during zmq_poll(): %s\n", ZMQ_STRERROR);
return AVERROR_EXTERNAL;
}
return items.revents & ev ? 0 : AVERROR(EAGAIN);
}
static int zmq_proto_wait_timeout(URLContext *h, void *socket, int write, int64_t timeout, AVIOInterruptCB *int_cb)
{
int ret;
int64_t wait_start = 0;
while (1) {
if (ff_check_interrupt(int_cb))
return AVERROR_EXIT;
ret = zmq_proto_wait(h, socket, write);
if (ret != AVERROR(EAGAIN))
return ret;
if (timeout > 0) {
if (!wait_start)
wait_start = av_gettime_relative();
else if (av_gettime_relative() - wait_start > timeout)
return AVERROR(ETIMEDOUT);
}
}
}
static int zmq_proto_open(URLContext *h, const char *uri, int flags)
{
int ret;
ZMQContext *s = h->priv_data;
s->pkt_size_overflow = 0;
h->is_streamed = 1;
if (s->pkt_size > 0)
h->max_packet_size = s->pkt_size;
s->context = zmq_ctx_new();
if (!s->context) {
/*errno not set on failure during zmq_ctx_new()*/
av_log(h, AV_LOG_ERROR, "Error occurred during zmq_ctx_new()\n");
return AVERROR_EXTERNAL;
}
if (av_strstart(uri, "zmq:", &uri)) {
av_log(h, AV_LOG_ERROR, "URL %s lacks prefix\n", uri);
return AVERROR(EINVAL);
}
/*publish during write*/
if (h->flags & AVIO_FLAG_WRITE) {
s->socket = zmq_socket(s->context, ZMQ_PUB);
if (!s->socket) {
av_log(h, AV_LOG_ERROR, "Error occurred during zmq_socket(): %s\n", ZMQ_STRERROR);
goto fail_term;
}
ret = zmq_bind(s->socket, uri);
if (ret == -1) {
av_log(h, AV_LOG_ERROR, "Error occurred during zmq_bind(): %s\n", ZMQ_STRERROR);
goto fail_close;
}
}
/*subscribe for read*/
if (h->flags & AVIO_FLAG_READ) {
s->socket = zmq_socket(s->context, ZMQ_SUB);
if (!s->socket) {
av_log(h, AV_LOG_ERROR, "Error occurred during zmq_socket(): %s\n", ZMQ_STRERROR);
goto fail_term;
}
ret = zmq_setsockopt(s->socket, ZMQ_SUBSCRIBE, "", 0);
if (ret == -1) {
av_log(h, AV_LOG_ERROR, "Error occurred during zmq_setsockopt(): %s\n", ZMQ_STRERROR);
goto fail_close;
}
ret = zmq_connect(s->socket, uri);
if (ret == -1) {
av_log(h, AV_LOG_ERROR, "Error occurred during zmq_connect(): %s\n", ZMQ_STRERROR);
goto fail_close;
}
}
return 0;
fail_close:
zmq_close(s->socket);
fail_term:
zmq_ctx_term(s->context);
return AVERROR_EXTERNAL;
}
static int zmq_proto_write(URLContext *h, const unsigned char *buf, int size)
{
int ret;
ZMQContext *s = h->priv_data;
ret = zmq_proto_wait_timeout(h, s->socket, 1, h->rw_timeout, &h->interrupt_callback);
if (ret)
return ret;
ret = zmq_send(s->socket, buf, size, 0);
if (ret == -1) {
av_log(h, AV_LOG_ERROR, "Error occurred during zmq_send(): %s\n", ZMQ_STRERROR);
return AVERROR_EXTERNAL;
}
return ret; /*number of bytes sent*/
}
static int zmq_proto_read(URLContext *h, unsigned char *buf, int size)
{
int ret;
ZMQContext *s = h->priv_data;
ret = zmq_proto_wait_timeout(h, s->socket, 0, h->rw_timeout, &h->interrupt_callback);
if (ret)
return ret;
ret = zmq_recv(s->socket, buf, size, 0);
if (ret == -1) {
av_log(h, AV_LOG_ERROR, "Error occurred during zmq_recv(): %s\n", ZMQ_STRERROR);
return AVERROR_EXTERNAL;
}
if (ret > size) {
s->pkt_size_overflow = FFMAX(s->pkt_size_overflow, ret);
av_log(h, AV_LOG_WARNING, "Message exceeds available space in the buffer. Message will be truncated. Setting -pkt_size %d may resolve the issue.\n", s->pkt_size_overflow);
ret = size;
}
return ret; /*number of bytes read*/
}
static int zmq_proto_close(URLContext *h)
{
ZMQContext *s = h->priv_data;
zmq_close(s->socket);
zmq_ctx_term(s->context);
return 0;
}
static const AVClass zmq_context_class = {
.class_name = "zmq",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
const URLProtocol ff_libzmq_protocol = {
.name = "zmq",
.url_close = zmq_proto_close,
.url_open = zmq_proto_open,
.url_read = zmq_proto_read,
.url_write = zmq_proto_write,
.priv_data_size = sizeof(ZMQContext),
.priv_data_class = &zmq_context_class,
.flags = URL_PROTOCOL_FLAG_NETWORK,
};
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