ffmpeg.libavutil.threadmessage source code

1 /*
2  * This file is part of FFmpeg.
3  *
4  * FFmpeg is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public License
6  * as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * FFmpeg is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public License
15  * along with FFmpeg; if not, write to the Free Software Foundation, Inc.,
16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18 module ffmpeg.libavutil.threadmessage;
19 extern (C) @nogc nothrow:
20 
21 struct AVThreadMessageQueue;
22 
23 enum AVThreadMessageFlags
24 {
25     /**
26      * Perform non-blocking operation.
27      * If this flag is set, send and recv operations are non-blocking and
28      * return AVERROR(EAGAIN) immediately if they can not proceed.
29      */
30     AV_THREAD_MESSAGE_NONBLOCK = 1
31 }
32 
33 /**
34  * Allocate a new message queue.
35  *
36  * @param mq      pointer to the message queue
37  * @param nelem   maximum number of elements in the queue
38  * @param elsize  size of each element in the queue
39  * @return  >=0 for success; <0 for error, in particular AVERROR(ENOSYS) if
40  *          lavu was built without thread support
41  */
42 int av_thread_message_queue_alloc (
43     AVThreadMessageQueue** mq,
44     uint nelem,
45     uint elsize);
46 
47 /**
48  * Free a message queue.
49  *
50  * The message queue must no longer be in use by another thread.
51  */
52 void av_thread_message_queue_free (AVThreadMessageQueue** mq);
53 
54 /**
55  * Send a message on the queue.
56  */
57 int av_thread_message_queue_send (
58     AVThreadMessageQueue* mq,
59     void* msg,
60     uint flags);
61 
62 /**
63  * Receive a message from the queue.
64  */
65 int av_thread_message_queue_recv (
66     AVThreadMessageQueue* mq,
67     void* msg,
68     uint flags);
69 
70 /**
71  * Set the sending error code.
72  *
73  * If the error code is set to non-zero, av_thread_message_queue_send() will
74  * return it immediately. Conventional values, such as AVERROR_EOF or
75  * AVERROR(EAGAIN), can be used to cause the sending thread to stop or
76  * suspend its operation.
77  */
78 void av_thread_message_queue_set_err_send (AVThreadMessageQueue* mq, int err);
79 
80 /**
81  * Set the receiving error code.
82  *
83  * If the error code is set to non-zero, av_thread_message_queue_recv() will
84  * return it immediately when there are no longer available messages.
85  * Conventional values, such as AVERROR_EOF or AVERROR(EAGAIN), can be used
86  * to cause the receiving thread to stop or suspend its operation.
87  */
88 void av_thread_message_queue_set_err_recv (AVThreadMessageQueue* mq, int err);
89 
90 /**
91  * Set the optional free message callback function which will be called if an
92  * operation is removing messages from the queue.
93  */
94 void av_thread_message_queue_set_free_func (
95     AVThreadMessageQueue* mq,
96     void function (void* msg) free_func);
97 
98 /**
99  * Return the current number of messages in the queue.
100  *
101  * @return the current number of messages or AVERROR(ENOSYS) if lavu was built
102  *         without thread support
103  */
104 int av_thread_message_queue_nb_elems (AVThreadMessageQueue* mq);
105 
106 /**
107  * Flush the message queue
108  *
109  * This function is mostly equivalent to reading and free-ing every message
110  * except that it will be done in a single operation (no lock/unlock between
111  * reads).
112  */
113 void av_thread_message_flush (AVThreadMessageQueue* mq);
114 
115 /* AVUTIL_THREADMESSAGE_H */