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 
19 module ffmpeg.libavutil.threadmessage;
20 
21 extern (C):
22 import ffmpeg; @nogc nothrow:
23 
24 struct AVThreadMessageQueue;
25 
26 enum AVThreadMessageFlags
27 {
28     /**
29      * Perform non-blocking operation.
30      * If this flag is set, send and recv operations are non-blocking and
31      * return AVERROR(EAGAIN) immediately if they can not proceed.
32      */
33     AV_THREAD_MESSAGE_NONBLOCK = 1
34 }
35 
36 /**
37  * Allocate a new message queue.
38  *
39  * @param mq      pointer to the message queue
40  * @param nelem   maximum number of elements in the queue
41  * @param elsize  size of each element in the queue
42  * @return  >=0 for success; <0 for error, in particular AVERROR(ENOSYS) if
43  *          lavu was built without thread support
44  */
45 int av_thread_message_queue_alloc (
46     AVThreadMessageQueue** mq,
47     uint nelem,
48     uint elsize);
49 
50 /**
51  * Free a message queue.
52  *
53  * The message queue must no longer be in use by another thread.
54  */
55 void av_thread_message_queue_free (AVThreadMessageQueue** mq);
56 
57 /**
58  * Send a message on the queue.
59  */
60 int av_thread_message_queue_send (
61     AVThreadMessageQueue* mq,
62     void* msg,
63     uint flags);
64 
65 /**
66  * Receive a message from the queue.
67  */
68 int av_thread_message_queue_recv (
69     AVThreadMessageQueue* mq,
70     void* msg,
71     uint flags);
72 
73 /**
74  * Set the sending error code.
75  *
76  * If the error code is set to non-zero, av_thread_message_queue_send() will
77  * return it immediately. Conventional values, such as AVERROR_EOF or
78  * AVERROR(EAGAIN), can be used to cause the sending thread to stop or
79  * suspend its operation.
80  */
81 void av_thread_message_queue_set_err_send (AVThreadMessageQueue* mq, int err);
82 
83 /**
84  * Set the receiving error code.
85  *
86  * If the error code is set to non-zero, av_thread_message_queue_recv() will
87  * return it immediately when there are no longer available messages.
88  * Conventional values, such as AVERROR_EOF or AVERROR(EAGAIN), can be used
89  * to cause the receiving thread to stop or suspend its operation.
90  */
91 void av_thread_message_queue_set_err_recv (AVThreadMessageQueue* mq, int err);
92 
93 /**
94  * Set the optional free message callback function which will be called if an
95  * operation is removing messages from the queue.
96  */
97 void av_thread_message_queue_set_free_func (
98     AVThreadMessageQueue* mq,
99     void function (void* msg) free_func);
100 
101 /**
102  * Return the current number of messages in the queue.
103  *
104  * @return the current number of messages or AVERROR(ENOSYS) if lavu was built
105  *         without thread support
106  */
107 int av_thread_message_queue_nb_elems (AVThreadMessageQueue* mq);
108 
109 /**
110  * Flush the message queue
111  *
112  * This function is mostly equivalent to reading and free-ing every message
113  * except that it will be done in a single operation (no lock/unlock between
114  * reads).
115  */
116 void av_thread_message_flush (AVThreadMessageQueue* mq);
117 
118 /* AVUTIL_THREADMESSAGE_H */