/* * 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_THREADMESSAGE_H#define AVUTIL_THREADMESSAGE_H typedef struct AVThreadMessageQueue AVThreadMessageQueue; typedef enum AVThreadMessageFlags {     /**     * Perform non-blocking operation.     * If this flag is set, send and recv operations are non-blocking and     * return AVERROR(EAGAIN) immediately if they can not proceed.     */    AV_THREAD_MESSAGE_NONBLOCK = 1, } AVThreadMessageFlags; /** * Allocate a new message queue. * * @param mq      pointer to the message queue * @param nelem   maximum number of elements in the queue * @param elsize  size of each element in the queue * @return  >=0 for success; <0 for error, in particular AVERROR(ENOSYS) if *          lavu was built without thread support */int av_thread_message_queue_alloc(AVThreadMessageQueue **mq,                                  unsigned nelem,                                  unsigned elsize); /** * Free a message queue. * * The message queue must no longer be in use by another thread. */void av_thread_message_queue_free(AVThreadMessageQueue **mq); /** * Send a message on the queue. */int av_thread_message_queue_send(AVThreadMessageQueue *mq,                                 void *msg,                                 unsigned flags); /** * Receive a message from the queue. */int av_thread_message_queue_recv(AVThreadMessageQueue *mq,                                 void *msg,                                 unsigned flags); /** * Set the sending error code. * * If the error code is set to non-zero, av_thread_message_queue_send() will * return it immediately. Conventional values, such as AVERROR_EOF or * AVERROR(EAGAIN), can be used to cause the sending thread to stop or * suspend its operation. */void av_thread_message_queue_set_err_send(AVThreadMessageQueue *mq,                                          int err); /** * Set the receiving error code. * * If the error code is set to non-zero, av_thread_message_queue_recv() will * return it immediately when there are no longer available messages. * Conventional values, such as AVERROR_EOF or AVERROR(EAGAIN), can be used * to cause the receiving thread to stop or suspend its operation. */void av_thread_message_queue_set_err_recv(AVThreadMessageQueue *mq,                                          int err); /** * Set the optional free message callback function which will be called if an * operation is removing messages from the queue. */void av_thread_message_queue_set_free_func(AVThreadMessageQueue *mq,                                           void (*free_func)(void *msg)); /** * Flush the message queue * * This function is mostly equivalent to reading and free-ing every message * except that it will be done in a single operation (no lock/unlock between * reads). */void av_thread_message_flush(AVThreadMessageQueue *mq); #endif /* AVUTIL_THREADMESSAGE_H */