libavfilter/f_zmq.c
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 /*
  * Copyright (c) 2013 Stefano Sabatini
  *
  * 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
  */
 
 /**
  * @file
  * receive commands through libzeromq and broker them to filters
  */
 
 #include <zmq.h>
 #include "libavutil/avstring.h"
 #include "libavutil/bprint.h"
 #include "libavutil/opt.h"
 #include "avfilter.h"
 #include "internal.h"
 #include "avfiltergraph.h"
 #include "audio.h"
 #include "video.h"
 
 typedef struct {
     const AVClass *class;
     void *zmq;
     void *responder;
     char *bind_address;
     int command_count;
 } ZMQContext;
 
 #define OFFSET(x) offsetof(ZMQContext, x)
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM | AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_VIDEO_PARAM
 static const AVOption options[] = {
     { "bind_address", "set bind address", OFFSET(bind_address), AV_OPT_TYPE_STRING, {.str = "tcp://*:5555"}, 0, 0, FLAGS },
     { "b",            "set bind address", OFFSET(bind_address), AV_OPT_TYPE_STRING, {.str = "tcp://*:5555"}, 0, 0, FLAGS },
     { NULL }
 };
 
 static av_cold int init(AVFilterContext *ctx)
 {
     ZMQContext *zmq = ctx->priv;
 
     zmq->zmq = zmq_ctx_new();
     if (!zmq->zmq) {
         av_log(ctx, AV_LOG_ERROR,
                "Could not create ZMQ context: %s\n", zmq_strerror(errno));
         return AVERROR_EXTERNAL;
     }
 
     zmq->responder = zmq_socket(zmq->zmq, ZMQ_REP);
     if (!zmq->responder) {
         av_log(ctx, AV_LOG_ERROR,
                "Could not create ZMQ socket: %s\n", zmq_strerror(errno));
         return AVERROR_EXTERNAL;
     }
 
     if (zmq_bind(zmq->responder, zmq->bind_address) == -1) {
         av_log(ctx, AV_LOG_ERROR,
                "Could not bind ZMQ socket to address '%s': %s\n",
                zmq->bind_address, zmq_strerror(errno));
         return AVERROR_EXTERNAL;
     }
 
     zmq->command_count = -1;
     return 0;
 }
 
 static void av_cold uninit(AVFilterContext *ctx)
 {
     ZMQContext *zmq = ctx->priv;
 
     zmq_close(zmq->responder);
     zmq_ctx_destroy(zmq->zmq);
 }
 
 typedef struct {
     char *target, *command, *arg;
 } Command;
 
 #define SPACES " \f\t\n\r"
 
 static int parse_command(Command *cmd, const char *command_str, void *log_ctx)
 {
     const char **buf = &command_str;
 
     cmd->target = av_get_token(buf, SPACES);
     if (!cmd->target || !cmd->target[0]) {
         av_log(log_ctx, AV_LOG_ERROR,
                "No target specified in command '%s'\n", command_str);
         return AVERROR(EINVAL);
     }
 
     cmd->command = av_get_token(buf, SPACES);
     if (!cmd->command || !cmd->command[0]) {
         av_log(log_ctx, AV_LOG_ERROR,
                "No command specified in command '%s'\n", command_str);
         return AVERROR(EINVAL);
     }
 
     cmd->arg = av_get_token(buf, SPACES);
     return 0;
 }
 
 static int recv_msg(AVFilterContext *ctx, char **buf, int *buf_size)
 {
     ZMQContext *zmq = ctx->priv;
     zmq_msg_t msg;
     int ret = 0;
 
     if (zmq_msg_init(&msg) == -1) {
         av_log(ctx, AV_LOG_WARNING,
                "Could not initialize receive message: %s\n", zmq_strerror(errno));
         return AVERROR_EXTERNAL;
     }
 
     if (zmq_msg_recv(&msg, zmq->responder, ZMQ_DONTWAIT) == -1) {
         if (errno != EAGAIN)
             av_log(ctx, AV_LOG_WARNING,
                    "Could not receive message: %s\n", zmq_strerror(errno));
         ret = AVERROR_EXTERNAL;
         goto end;
     }
 
     *buf_size = zmq_msg_size(&msg) + 1;
     *buf = av_malloc(*buf_size);
     if (!*buf) {
         ret = AVERROR(ENOMEM);
         goto end;
     }
     memcpy(*buf, zmq_msg_data(&msg), *buf_size);
     (*buf)[*buf_size-1] = 0;
 
 end:
     zmq_msg_close(&msg);
     return ret;
 }
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *ref)
 {
     AVFilterContext *ctx = inlink->dst;
     ZMQContext *zmq = ctx->priv;
 
     while (1) {
         char cmd_buf[1024];
         char *recv_buf, *send_buf;
         int recv_buf_size;
         Command cmd = {0};
         int ret;
 
         /* receive command */
         if (recv_msg(ctx, &recv_buf, &recv_buf_size) < 0)
             break;
         zmq->command_count++;
 
         /* parse command */
         if (parse_command(&cmd, recv_buf, ctx) < 0) {
             av_log(ctx, AV_LOG_ERROR, "Could not parse command #%d\n", zmq->command_count);
             goto end;
         }
 
         /* process command */
         av_log(ctx, AV_LOG_VERBOSE,
                "Processing command #%d target:%s command:%s arg:%s\n",
                zmq->command_count, cmd.target, cmd.command, cmd.arg);
         ret = avfilter_graph_send_command(inlink->graph,
                                           cmd.target, cmd.command, cmd.arg,
                                           cmd_buf, sizeof(cmd_buf),
                                           AVFILTER_CMD_FLAG_ONE);
         send_buf = av_asprintf("%d %s%s%s",
                                -ret, av_err2str(ret), cmd_buf[0] ? "\n" : "", cmd_buf);
         if (!send_buf) {
             ret = AVERROR(ENOMEM);
             goto end;
         }
         av_log(ctx, AV_LOG_VERBOSE,
                "Sending command reply for command #%d:\n%s\n",
                zmq->command_count, send_buf);
         if (zmq_send(zmq->responder, send_buf, strlen(send_buf), 0) == -1)
             av_log(ctx, AV_LOG_ERROR, "Failed to send reply for command #%d: %s\n",
                    zmq->command_count, zmq_strerror(ret));
 
     end:
         av_freep(&send_buf);
         av_freep(&recv_buf);
         recv_buf_size = 0;
         av_freep(&cmd.target);
         av_freep(&cmd.command);
         av_freep(&cmd.arg);
     }
 
     return ff_filter_frame(ctx->outputs[0], ref);
 }
 
 #if CONFIG_ZMQ_FILTER
 
 #define zmq_options options
 AVFILTER_DEFINE_CLASS(zmq);
 
 static const AVFilterPad zmq_inputs[] = {
     {
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         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .filter_frame = filter_frame,
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     },
     { NULL }
 };
 
 static const AVFilterPad zmq_outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }
 };
 
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 AVFilter ff_vf_zmq = {
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     .name        = "zmq",
     .description = NULL_IF_CONFIG_SMALL("Receive commands through ZMQ and broker them to filters."),
     .init        = init,
     .uninit      = uninit,
     .priv_size   = sizeof(ZMQContext),
     .inputs      = zmq_inputs,
     .outputs     = zmq_outputs,
     .priv_class  = &zmq_class,
 };
 
 #endif
 
 #if CONFIG_AZMQ_FILTER
 
 #define azmq_options options
 AVFILTER_DEFINE_CLASS(azmq);
 
 static const AVFilterPad azmq_inputs[] = {
     {
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         .name         = "default",
         .type         = AVMEDIA_TYPE_AUDIO,
         .filter_frame = filter_frame,
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     },
     { NULL }
 };
 
 static const AVFilterPad azmq_outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_AUDIO,
     },
     { NULL }
 };
 
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 AVFilter ff_af_azmq = {
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     .name        = "azmq",
     .description = NULL_IF_CONFIG_SMALL("Receive commands through ZMQ and broker them to filters."),
     .init        = init,
     .uninit      = uninit,
     .priv_size   = sizeof(ZMQContext),
     .inputs      = azmq_inputs,
     .outputs     = azmq_outputs,
     .priv_class  = &azmq_class,
 };
 
 #endif