1 /*
2  * Copyright (c) 2014 Nicolas George
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public License
8  * as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public License
17  * along with FFmpeg; if not, write to the Free Software Foundation, Inc.,
18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include "fifo.h"
22 #include "threadmessage.h"
23 #include "thread.h"
24 
25 struct AVThreadMessageQueue {
26 #if HAVE_THREADS
27     AVFifoBuffer *fifo;
28     pthread_mutex_t lock;
29     pthread_cond_t cond_recv;
30     pthread_cond_t cond_send;
31     int err_send;
32     int err_recv;
33     unsigned elsize;
34     void (*free_func)(void *msg);
35 #else
36     int dummy;
37 #endif
38 };
39 
av_thread_message_queue_alloc(AVThreadMessageQueue ** mq,unsigned nelem,unsigned elsize)40 int av_thread_message_queue_alloc(AVThreadMessageQueue **mq,
41                                   unsigned nelem,
42                                   unsigned elsize)
43 {
44 #if HAVE_THREADS
45     AVThreadMessageQueue *rmq;
46     int ret = 0;
47 
48     if (nelem > INT_MAX / elsize)
49         return AVERROR(EINVAL);
50     if (!(rmq = av_mallocz(sizeof(*rmq))))
51         return AVERROR(ENOMEM);
52     if ((ret = pthread_mutex_init(&rmq->lock, NULL))) {
53         av_free(rmq);
54         return AVERROR(ret);
55     }
56     if ((ret = pthread_cond_init(&rmq->cond_recv, NULL))) {
57         pthread_mutex_destroy(&rmq->lock);
58         av_free(rmq);
59         return AVERROR(ret);
60     }
61     if ((ret = pthread_cond_init(&rmq->cond_send, NULL))) {
62         pthread_cond_destroy(&rmq->cond_recv);
63         pthread_mutex_destroy(&rmq->lock);
64         av_free(rmq);
65         return AVERROR(ret);
66     }
67     if (!(rmq->fifo = av_fifo_alloc(elsize * nelem))) {
68         pthread_cond_destroy(&rmq->cond_send);
69         pthread_cond_destroy(&rmq->cond_recv);
70         pthread_mutex_destroy(&rmq->lock);
71         av_free(rmq);
72         return AVERROR(ENOMEM);
73     }
74     rmq->elsize = elsize;
75     *mq = rmq;
76     return 0;
77 #else
78     *mq = NULL;
79     return AVERROR(ENOSYS);
80 #endif /* HAVE_THREADS */
81 }
82 
av_thread_message_queue_set_free_func(AVThreadMessageQueue * mq,void (* free_func)(void * msg))83 void av_thread_message_queue_set_free_func(AVThreadMessageQueue *mq,
84                                            void (*free_func)(void *msg))
85 {
86 #if HAVE_THREADS
87     mq->free_func = free_func;
88 #endif
89 }
90 
av_thread_message_queue_free(AVThreadMessageQueue ** mq)91 void av_thread_message_queue_free(AVThreadMessageQueue **mq)
92 {
93 #if HAVE_THREADS
94     if (*mq) {
95         av_thread_message_flush(*mq);
96         av_fifo_freep(&(*mq)->fifo);
97         pthread_cond_destroy(&(*mq)->cond_send);
98         pthread_cond_destroy(&(*mq)->cond_recv);
99         pthread_mutex_destroy(&(*mq)->lock);
100         av_freep(mq);
101     }
102 #endif
103 }
104 
av_thread_message_queue_nb_elems(AVThreadMessageQueue * mq)105 int av_thread_message_queue_nb_elems(AVThreadMessageQueue *mq)
106 {
107 #if HAVE_THREADS
108     int ret;
109     pthread_mutex_lock(&mq->lock);
110     ret = av_fifo_size(mq->fifo);
111     pthread_mutex_unlock(&mq->lock);
112     return ret / mq->elsize;
113 #else
114     return AVERROR(ENOSYS);
115 #endif
116 }
117 
118 #if HAVE_THREADS
119 
av_thread_message_queue_send_locked(AVThreadMessageQueue * mq,void * msg,unsigned flags)120 static int av_thread_message_queue_send_locked(AVThreadMessageQueue *mq,
121                                                void *msg,
122                                                unsigned flags)
123 {
124     while (!mq->err_send && av_fifo_space(mq->fifo) < mq->elsize) {
125         if ((flags & AV_THREAD_MESSAGE_NONBLOCK))
126             return AVERROR(EAGAIN);
127         pthread_cond_wait(&mq->cond_send, &mq->lock);
128     }
129     if (mq->err_send)
130         return mq->err_send;
131     av_fifo_generic_write(mq->fifo, msg, mq->elsize, NULL);
132     /* one message is sent, signal one receiver */
133     pthread_cond_signal(&mq->cond_recv);
134     return 0;
135 }
136 
av_thread_message_queue_recv_locked(AVThreadMessageQueue * mq,void * msg,unsigned flags)137 static int av_thread_message_queue_recv_locked(AVThreadMessageQueue *mq,
138                                                void *msg,
139                                                unsigned flags)
140 {
141     while (!mq->err_recv && av_fifo_size(mq->fifo) < mq->elsize) {
142         if ((flags & AV_THREAD_MESSAGE_NONBLOCK))
143             return AVERROR(EAGAIN);
144         pthread_cond_wait(&mq->cond_recv, &mq->lock);
145     }
146     if (av_fifo_size(mq->fifo) < mq->elsize)
147         return mq->err_recv;
148     av_fifo_generic_read(mq->fifo, msg, mq->elsize, NULL);
149     /* one message space appeared, signal one sender */
150     pthread_cond_signal(&mq->cond_send);
151     return 0;
152 }
153 
154 #endif /* HAVE_THREADS */
155 
av_thread_message_queue_send(AVThreadMessageQueue * mq,void * msg,unsigned flags)156 int av_thread_message_queue_send(AVThreadMessageQueue *mq,
157                                  void *msg,
158                                  unsigned flags)
159 {
160 #if HAVE_THREADS
161     int ret;
162 
163     pthread_mutex_lock(&mq->lock);
164     ret = av_thread_message_queue_send_locked(mq, msg, flags);
165     pthread_mutex_unlock(&mq->lock);
166     return ret;
167 #else
168     return AVERROR(ENOSYS);
169 #endif /* HAVE_THREADS */
170 }
171 
av_thread_message_queue_recv(AVThreadMessageQueue * mq,void * msg,unsigned flags)172 int av_thread_message_queue_recv(AVThreadMessageQueue *mq,
173                                  void *msg,
174                                  unsigned flags)
175 {
176 #if HAVE_THREADS
177     int ret;
178 
179     pthread_mutex_lock(&mq->lock);
180     ret = av_thread_message_queue_recv_locked(mq, msg, flags);
181     pthread_mutex_unlock(&mq->lock);
182     return ret;
183 #else
184     return AVERROR(ENOSYS);
185 #endif /* HAVE_THREADS */
186 }
187 
av_thread_message_queue_set_err_send(AVThreadMessageQueue * mq,int err)188 void av_thread_message_queue_set_err_send(AVThreadMessageQueue *mq,
189                                           int err)
190 {
191 #if HAVE_THREADS
192     pthread_mutex_lock(&mq->lock);
193     mq->err_send = err;
194     pthread_cond_broadcast(&mq->cond_send);
195     pthread_mutex_unlock(&mq->lock);
196 #endif /* HAVE_THREADS */
197 }
198 
av_thread_message_queue_set_err_recv(AVThreadMessageQueue * mq,int err)199 void av_thread_message_queue_set_err_recv(AVThreadMessageQueue *mq,
200                                           int err)
201 {
202 #if HAVE_THREADS
203     pthread_mutex_lock(&mq->lock);
204     mq->err_recv = err;
205     pthread_cond_broadcast(&mq->cond_recv);
206     pthread_mutex_unlock(&mq->lock);
207 #endif /* HAVE_THREADS */
208 }
209 
210 #if HAVE_THREADS
free_func_wrap(void * arg,void * msg,int size)211 static void free_func_wrap(void *arg, void *msg, int size)
212 {
213     AVThreadMessageQueue *mq = arg;
214     mq->free_func(msg);
215 }
216 #endif
217 
av_thread_message_flush(AVThreadMessageQueue * mq)218 void av_thread_message_flush(AVThreadMessageQueue *mq)
219 {
220 #if HAVE_THREADS
221     int used, off;
222     void *free_func = mq->free_func;
223 
224     pthread_mutex_lock(&mq->lock);
225     used = av_fifo_size(mq->fifo);
226     if (free_func)
227         for (off = 0; off < used; off += mq->elsize)
228             av_fifo_generic_peek_at(mq->fifo, mq, off, mq->elsize, free_func_wrap);
229     av_fifo_drain(mq->fifo, used);
230     /* only the senders need to be notified since the queue is empty and there
231      * is nothing to read */
232     pthread_cond_broadcast(&mq->cond_send);
233     pthread_mutex_unlock(&mq->lock);
234 #endif /* HAVE_THREADS */
235 }
236