1 /*
2 * Input async protocol.
3 * Copyright (c) 2015 Zhang Rui <bbcallen@gmail.com>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 *
21 * Based on libavformat/cache.c by Michael Niedermayer
22 */
23
24 /**
25 * @TODO
26 * support timeout
27 * support work with concatdec, hls
28 */
29
30 #include "libavutil/avassert.h"
31 #include "libavutil/avstring.h"
32 #include "libavutil/error.h"
33 #include "libavutil/fifo.h"
34 #include "libavutil/log.h"
35 #include "libavutil/opt.h"
36 #include "libavutil/thread.h"
37 #include "url.h"
38 #include <stdint.h>
39
40 #if HAVE_UNISTD_H
41 #include <unistd.h>
42 #endif
43
44 #define BUFFER_CAPACITY (4 * 1024 * 1024)
45 #define READ_BACK_CAPACITY (4 * 1024 * 1024)
46 #define SHORT_SEEK_THRESHOLD (256 * 1024)
47
48 typedef struct RingBuffer
49 {
50 AVFifoBuffer *fifo;
51 int read_back_capacity;
52
53 int read_pos;
54 } RingBuffer;
55
56 typedef struct Context {
57 AVClass *class;
58 URLContext *inner;
59
60 int seek_request;
61 int64_t seek_pos;
62 int seek_whence;
63 int seek_completed;
64 int64_t seek_ret;
65
66 int inner_io_error;
67 int io_error;
68 int io_eof_reached;
69
70 int64_t logical_pos;
71 int64_t logical_size;
72 RingBuffer ring;
73
74 pthread_cond_t cond_wakeup_main;
75 pthread_cond_t cond_wakeup_background;
76 pthread_mutex_t mutex;
77 pthread_t async_buffer_thread;
78
79 int abort_request;
80 AVIOInterruptCB interrupt_callback;
81 } Context;
82
ring_init(RingBuffer * ring,unsigned int capacity,int read_back_capacity)83 static int ring_init(RingBuffer *ring, unsigned int capacity, int read_back_capacity)
84 {
85 memset(ring, 0, sizeof(RingBuffer));
86 ring->fifo = av_fifo_alloc(capacity + read_back_capacity);
87 if (!ring->fifo)
88 return AVERROR(ENOMEM);
89
90 ring->read_back_capacity = read_back_capacity;
91 return 0;
92 }
93
ring_destroy(RingBuffer * ring)94 static void ring_destroy(RingBuffer *ring)
95 {
96 av_fifo_freep(&ring->fifo);
97 }
98
ring_reset(RingBuffer * ring)99 static void ring_reset(RingBuffer *ring)
100 {
101 av_fifo_reset(ring->fifo);
102 ring->read_pos = 0;
103 }
104
ring_size(RingBuffer * ring)105 static int ring_size(RingBuffer *ring)
106 {
107 return av_fifo_size(ring->fifo) - ring->read_pos;
108 }
109
ring_space(RingBuffer * ring)110 static int ring_space(RingBuffer *ring)
111 {
112 return av_fifo_space(ring->fifo);
113 }
114
ring_generic_read(RingBuffer * ring,void * dest,int buf_size,void (* func)(void *,void *,int))115 static int ring_generic_read(RingBuffer *ring, void *dest, int buf_size, void (*func)(void*, void*, int))
116 {
117 int ret;
118
119 av_assert2(buf_size <= ring_size(ring));
120 ret = av_fifo_generic_peek_at(ring->fifo, dest, ring->read_pos, buf_size, func);
121 ring->read_pos += buf_size;
122
123 if (ring->read_pos > ring->read_back_capacity) {
124 av_fifo_drain(ring->fifo, ring->read_pos - ring->read_back_capacity);
125 ring->read_pos = ring->read_back_capacity;
126 }
127
128 return ret;
129 }
130
ring_generic_write(RingBuffer * ring,void * src,int size,int (* func)(void *,void *,int))131 static int ring_generic_write(RingBuffer *ring, void *src, int size, int (*func)(void*, void*, int))
132 {
133 av_assert2(size <= ring_space(ring));
134 return av_fifo_generic_write(ring->fifo, src, size, func);
135 }
136
ring_size_of_read_back(RingBuffer * ring)137 static int ring_size_of_read_back(RingBuffer *ring)
138 {
139 return ring->read_pos;
140 }
141
ring_drain(RingBuffer * ring,int offset)142 static int ring_drain(RingBuffer *ring, int offset)
143 {
144 av_assert2(offset >= -ring_size_of_read_back(ring));
145 av_assert2(offset <= ring_size(ring));
146 ring->read_pos += offset;
147 return 0;
148 }
149
async_check_interrupt(void * arg)150 static int async_check_interrupt(void *arg)
151 {
152 URLContext *h = arg;
153 Context *c = h->priv_data;
154
155 if (c->abort_request)
156 return 1;
157
158 if (ff_check_interrupt(&c->interrupt_callback))
159 c->abort_request = 1;
160
161 return c->abort_request;
162 }
163
wrapped_url_read(void * src,void * dst,int size)164 static int wrapped_url_read(void *src, void *dst, int size)
165 {
166 URLContext *h = src;
167 Context *c = h->priv_data;
168 int ret;
169
170 ret = ffurl_read(c->inner, dst, size);
171 c->inner_io_error = ret < 0 ? ret : 0;
172
173 return ret;
174 }
175
async_buffer_task(void * arg)176 static void *async_buffer_task(void *arg)
177 {
178 URLContext *h = arg;
179 Context *c = h->priv_data;
180 RingBuffer *ring = &c->ring;
181 int ret = 0;
182 int64_t seek_ret;
183
184 while (1) {
185 int fifo_space, to_copy;
186
187 pthread_mutex_lock(&c->mutex);
188 if (async_check_interrupt(h)) {
189 c->io_eof_reached = 1;
190 c->io_error = AVERROR_EXIT;
191 pthread_cond_signal(&c->cond_wakeup_main);
192 pthread_mutex_unlock(&c->mutex);
193 break;
194 }
195
196 if (c->seek_request) {
197 seek_ret = ffurl_seek(c->inner, c->seek_pos, c->seek_whence);
198 if (seek_ret >= 0) {
199 c->io_eof_reached = 0;
200 c->io_error = 0;
201 ring_reset(ring);
202 }
203
204 c->seek_completed = 1;
205 c->seek_ret = seek_ret;
206 c->seek_request = 0;
207
208
209 pthread_cond_signal(&c->cond_wakeup_main);
210 pthread_mutex_unlock(&c->mutex);
211 continue;
212 }
213
214 fifo_space = ring_space(ring);
215 if (c->io_eof_reached || fifo_space <= 0) {
216 pthread_cond_signal(&c->cond_wakeup_main);
217 pthread_cond_wait(&c->cond_wakeup_background, &c->mutex);
218 pthread_mutex_unlock(&c->mutex);
219 continue;
220 }
221 pthread_mutex_unlock(&c->mutex);
222
223 to_copy = FFMIN(4096, fifo_space);
224 ret = ring_generic_write(ring, (void *)h, to_copy, wrapped_url_read);
225
226 pthread_mutex_lock(&c->mutex);
227 if (ret <= 0) {
228 c->io_eof_reached = 1;
229 if (c->inner_io_error < 0)
230 c->io_error = c->inner_io_error;
231 }
232
233 pthread_cond_signal(&c->cond_wakeup_main);
234 pthread_mutex_unlock(&c->mutex);
235 }
236
237 return NULL;
238 }
239
async_open(URLContext * h,const char * arg,int flags,AVDictionary ** options)240 static int async_open(URLContext *h, const char *arg, int flags, AVDictionary **options)
241 {
242 Context *c = h->priv_data;
243 int ret;
244 AVIOInterruptCB interrupt_callback = {.callback = async_check_interrupt, .opaque = h};
245
246 av_strstart(arg, "async:", &arg);
247
248 ret = ring_init(&c->ring, BUFFER_CAPACITY, READ_BACK_CAPACITY);
249 if (ret < 0)
250 goto fifo_fail;
251
252 /* wrap interrupt callback */
253 c->interrupt_callback = h->interrupt_callback;
254 ret = ffurl_open_whitelist(&c->inner, arg, flags, &interrupt_callback, options, h->protocol_whitelist, h->protocol_blacklist, h);
255 if (ret != 0) {
256 av_log(h, AV_LOG_ERROR, "ffurl_open failed : %s, %s\n", av_err2str(ret), arg);
257 goto url_fail;
258 }
259
260 c->logical_size = ffurl_size(c->inner);
261 h->is_streamed = c->inner->is_streamed;
262
263 ret = pthread_mutex_init(&c->mutex, NULL);
264 if (ret != 0) {
265 ret = AVERROR(ret);
266 av_log(h, AV_LOG_ERROR, "pthread_mutex_init failed : %s\n", av_err2str(ret));
267 goto mutex_fail;
268 }
269
270 ret = pthread_cond_init(&c->cond_wakeup_main, NULL);
271 if (ret != 0) {
272 ret = AVERROR(ret);
273 av_log(h, AV_LOG_ERROR, "pthread_cond_init failed : %s\n", av_err2str(ret));
274 goto cond_wakeup_main_fail;
275 }
276
277 ret = pthread_cond_init(&c->cond_wakeup_background, NULL);
278 if (ret != 0) {
279 ret = AVERROR(ret);
280 av_log(h, AV_LOG_ERROR, "pthread_cond_init failed : %s\n", av_err2str(ret));
281 goto cond_wakeup_background_fail;
282 }
283
284 ret = pthread_create(&c->async_buffer_thread, NULL, async_buffer_task, h);
285 if (ret) {
286 ret = AVERROR(ret);
287 av_log(h, AV_LOG_ERROR, "pthread_create failed : %s\n", av_err2str(ret));
288 goto thread_fail;
289 }
290
291 return 0;
292
293 thread_fail:
294 pthread_cond_destroy(&c->cond_wakeup_background);
295 cond_wakeup_background_fail:
296 pthread_cond_destroy(&c->cond_wakeup_main);
297 cond_wakeup_main_fail:
298 pthread_mutex_destroy(&c->mutex);
299 mutex_fail:
300 ffurl_closep(&c->inner);
301 url_fail:
302 ring_destroy(&c->ring);
303 fifo_fail:
304 return ret;
305 }
306
async_close(URLContext * h)307 static int async_close(URLContext *h)
308 {
309 Context *c = h->priv_data;
310 int ret;
311
312 pthread_mutex_lock(&c->mutex);
313 c->abort_request = 1;
314 pthread_cond_signal(&c->cond_wakeup_background);
315 pthread_mutex_unlock(&c->mutex);
316
317 ret = pthread_join(c->async_buffer_thread, NULL);
318 if (ret != 0)
319 av_log(h, AV_LOG_ERROR, "pthread_join(): %s\n", av_err2str(ret));
320
321 pthread_cond_destroy(&c->cond_wakeup_background);
322 pthread_cond_destroy(&c->cond_wakeup_main);
323 pthread_mutex_destroy(&c->mutex);
324 ffurl_closep(&c->inner);
325 ring_destroy(&c->ring);
326
327 return 0;
328 }
329
async_read_internal(URLContext * h,void * dest,int size,int read_complete,void (* func)(void *,void *,int))330 static int async_read_internal(URLContext *h, void *dest, int size, int read_complete,
331 void (*func)(void*, void*, int))
332 {
333 Context *c = h->priv_data;
334 RingBuffer *ring = &c->ring;
335 int to_read = size;
336 int ret = 0;
337
338 pthread_mutex_lock(&c->mutex);
339
340 while (to_read > 0) {
341 int fifo_size, to_copy;
342 if (async_check_interrupt(h)) {
343 ret = AVERROR_EXIT;
344 break;
345 }
346 fifo_size = ring_size(ring);
347 to_copy = FFMIN(to_read, fifo_size);
348 if (to_copy > 0) {
349 ring_generic_read(ring, dest, to_copy, func);
350 if (!func)
351 dest = (uint8_t *)dest + to_copy;
352 c->logical_pos += to_copy;
353 to_read -= to_copy;
354 ret = size - to_read;
355
356 if (to_read <= 0 || !read_complete)
357 break;
358 } else if (c->io_eof_reached) {
359 if (ret <= 0) {
360 if (c->io_error)
361 ret = c->io_error;
362 else
363 ret = AVERROR_EOF;
364 }
365 break;
366 }
367 pthread_cond_signal(&c->cond_wakeup_background);
368 pthread_cond_wait(&c->cond_wakeup_main, &c->mutex);
369 }
370
371 pthread_cond_signal(&c->cond_wakeup_background);
372 pthread_mutex_unlock(&c->mutex);
373
374 return ret;
375 }
376
async_read(URLContext * h,unsigned char * buf,int size)377 static int async_read(URLContext *h, unsigned char *buf, int size)
378 {
379 return async_read_internal(h, buf, size, 0, NULL);
380 }
381
fifo_do_not_copy_func(void * dest,void * src,int size)382 static void fifo_do_not_copy_func(void* dest, void* src, int size) {
383 // do not copy
384 }
385
async_seek(URLContext * h,int64_t pos,int whence)386 static int64_t async_seek(URLContext *h, int64_t pos, int whence)
387 {
388 Context *c = h->priv_data;
389 RingBuffer *ring = &c->ring;
390 int64_t ret;
391 int64_t new_logical_pos;
392 int fifo_size;
393 int fifo_size_of_read_back;
394
395 if (whence == AVSEEK_SIZE) {
396 av_log(h, AV_LOG_TRACE, "async_seek: AVSEEK_SIZE: %"PRId64"\n", (int64_t)c->logical_size);
397 return c->logical_size;
398 } else if (whence == SEEK_CUR) {
399 av_log(h, AV_LOG_TRACE, "async_seek: %"PRId64"\n", pos);
400 new_logical_pos = pos + c->logical_pos;
401 } else if (whence == SEEK_SET){
402 av_log(h, AV_LOG_TRACE, "async_seek: %"PRId64"\n", pos);
403 new_logical_pos = pos;
404 } else {
405 return AVERROR(EINVAL);
406 }
407 if (new_logical_pos < 0)
408 return AVERROR(EINVAL);
409
410 fifo_size = ring_size(ring);
411 fifo_size_of_read_back = ring_size_of_read_back(ring);
412 if (new_logical_pos == c->logical_pos) {
413 /* current position */
414 return c->logical_pos;
415 } else if ((new_logical_pos >= (c->logical_pos - fifo_size_of_read_back)) &&
416 (new_logical_pos < (c->logical_pos + fifo_size + SHORT_SEEK_THRESHOLD))) {
417 int pos_delta = (int)(new_logical_pos - c->logical_pos);
418 /* fast seek */
419 av_log(h, AV_LOG_TRACE, "async_seek: fask_seek %"PRId64" from %d dist:%d/%d\n",
420 new_logical_pos, (int)c->logical_pos,
421 (int)(new_logical_pos - c->logical_pos), fifo_size);
422
423 if (pos_delta > 0) {
424 // fast seek forwards
425 async_read_internal(h, NULL, pos_delta, 1, fifo_do_not_copy_func);
426 } else {
427 // fast seek backwards
428 ring_drain(ring, pos_delta);
429 c->logical_pos = new_logical_pos;
430 }
431
432 return c->logical_pos;
433 } else if (c->logical_size <= 0) {
434 /* can not seek */
435 return AVERROR(EINVAL);
436 } else if (new_logical_pos > c->logical_size) {
437 /* beyond end */
438 return AVERROR(EINVAL);
439 }
440
441 pthread_mutex_lock(&c->mutex);
442
443 c->seek_request = 1;
444 c->seek_pos = new_logical_pos;
445 c->seek_whence = SEEK_SET;
446 c->seek_completed = 0;
447 c->seek_ret = 0;
448
449 while (1) {
450 if (async_check_interrupt(h)) {
451 ret = AVERROR_EXIT;
452 break;
453 }
454 if (c->seek_completed) {
455 if (c->seek_ret >= 0)
456 c->logical_pos = c->seek_ret;
457 ret = c->seek_ret;
458 break;
459 }
460 pthread_cond_signal(&c->cond_wakeup_background);
461 pthread_cond_wait(&c->cond_wakeup_main, &c->mutex);
462 }
463
464 pthread_mutex_unlock(&c->mutex);
465
466 return ret;
467 }
468
469 #define OFFSET(x) offsetof(Context, x)
470 #define D AV_OPT_FLAG_DECODING_PARAM
471
472 static const AVOption options[] = {
473 {NULL},
474 };
475
476 #undef D
477 #undef OFFSET
478
479 static const AVClass async_context_class = {
480 .class_name = "Async",
481 .item_name = av_default_item_name,
482 .option = options,
483 .version = LIBAVUTIL_VERSION_INT,
484 };
485
486 const URLProtocol ff_async_protocol = {
487 .name = "async",
488 .url_open2 = async_open,
489 .url_read = async_read,
490 .url_seek = async_seek,
491 .url_close = async_close,
492 .priv_data_size = sizeof(Context),
493 .priv_data_class = &async_context_class,
494 };
495
496 #if 0
497
498 #define TEST_SEEK_POS (1536)
499 #define TEST_STREAM_SIZE (2048)
500
501 typedef struct TestContext {
502 AVClass *class;
503 int64_t logical_pos;
504 int64_t logical_size;
505
506 /* options */
507 int opt_read_error;
508 } TestContext;
509
510 static int async_test_open(URLContext *h, const char *arg, int flags, AVDictionary **options)
511 {
512 TestContext *c = h->priv_data;
513 c->logical_pos = 0;
514 c->logical_size = TEST_STREAM_SIZE;
515 return 0;
516 }
517
518 static int async_test_close(URLContext *h)
519 {
520 return 0;
521 }
522
523 static int async_test_read(URLContext *h, unsigned char *buf, int size)
524 {
525 TestContext *c = h->priv_data;
526 int i;
527 int read_len = 0;
528
529 if (c->opt_read_error)
530 return c->opt_read_error;
531
532 if (c->logical_pos >= c->logical_size)
533 return AVERROR_EOF;
534
535 for (i = 0; i < size; ++i) {
536 buf[i] = c->logical_pos & 0xFF;
537
538 c->logical_pos++;
539 read_len++;
540
541 if (c->logical_pos >= c->logical_size)
542 break;
543 }
544
545 return read_len;
546 }
547
548 static int64_t async_test_seek(URLContext *h, int64_t pos, int whence)
549 {
550 TestContext *c = h->priv_data;
551 int64_t new_logical_pos;
552
553 if (whence == AVSEEK_SIZE) {
554 return c->logical_size;
555 } else if (whence == SEEK_CUR) {
556 new_logical_pos = pos + c->logical_pos;
557 } else if (whence == SEEK_SET){
558 new_logical_pos = pos;
559 } else {
560 return AVERROR(EINVAL);
561 }
562 if (new_logical_pos < 0)
563 return AVERROR(EINVAL);
564
565 c->logical_pos = new_logical_pos;
566 return new_logical_pos;
567 }
568
569 #define OFFSET(x) offsetof(TestContext, x)
570 #define D AV_OPT_FLAG_DECODING_PARAM
571
572 static const AVOption async_test_options[] = {
573 { "async-test-read-error", "cause read fail",
574 OFFSET(opt_read_error), AV_OPT_TYPE_INT, { .i64 = 0 }, INT_MIN, INT_MAX, .flags = D },
575 {NULL},
576 };
577
578 #undef D
579 #undef OFFSET
580
581 static const AVClass async_test_context_class = {
582 .class_name = "Async-Test",
583 .item_name = av_default_item_name,
584 .option = async_test_options,
585 .version = LIBAVUTIL_VERSION_INT,
586 };
587
588 const URLProtocol ff_async_test_protocol = {
589 .name = "async-test",
590 .url_open2 = async_test_open,
591 .url_read = async_test_read,
592 .url_seek = async_test_seek,
593 .url_close = async_test_close,
594 .priv_data_size = sizeof(TestContext),
595 .priv_data_class = &async_test_context_class,
596 };
597
598 int main(void)
599 {
600 URLContext *h = NULL;
601 int i;
602 int ret;
603 int64_t size;
604 int64_t pos;
605 int64_t read_len;
606 unsigned char buf[4096];
607 AVDictionary *opts = NULL;
608
609 ffurl_register_protocol(&ff_async_protocol);
610 ffurl_register_protocol(&ff_async_test_protocol);
611
612 /*
613 * test normal read
614 */
615 ret = ffurl_open_whitelist(&h, "async:async-test:", AVIO_FLAG_READ,
616 NULL, NULL, NULL, NULL, NULL);
617 printf("open: %d\n", ret);
618
619 size = ffurl_size(h);
620 printf("size: %"PRId64"\n", size);
621
622 pos = ffurl_seek(h, 0, SEEK_CUR);
623 read_len = 0;
624 while (1) {
625 ret = ffurl_read(h, buf, sizeof(buf));
626 if (ret == AVERROR_EOF) {
627 printf("read-error: AVERROR_EOF at %"PRId64"\n", ffurl_seek(h, 0, SEEK_CUR));
628 break;
629 }
630 else if (ret == 0)
631 break;
632 else if (ret < 0) {
633 printf("read-error: %d at %"PRId64"\n", ret, ffurl_seek(h, 0, SEEK_CUR));
634 goto fail;
635 } else {
636 for (i = 0; i < ret; ++i) {
637 if (buf[i] != (pos & 0xFF)) {
638 printf("read-mismatch: actual %d, expecting %d, at %"PRId64"\n",
639 (int)buf[i], (int)(pos & 0xFF), pos);
640 break;
641 }
642 pos++;
643 }
644 }
645
646 read_len += ret;
647 }
648 printf("read: %"PRId64"\n", read_len);
649
650 /*
651 * test normal seek
652 */
653 ret = ffurl_read(h, buf, 1);
654 printf("read: %d\n", ret);
655
656 pos = ffurl_seek(h, TEST_SEEK_POS, SEEK_SET);
657 printf("seek: %"PRId64"\n", pos);
658
659 read_len = 0;
660 while (1) {
661 ret = ffurl_read(h, buf, sizeof(buf));
662 if (ret == AVERROR_EOF)
663 break;
664 else if (ret == 0)
665 break;
666 else if (ret < 0) {
667 printf("read-error: %d at %"PRId64"\n", ret, ffurl_seek(h, 0, SEEK_CUR));
668 goto fail;
669 } else {
670 for (i = 0; i < ret; ++i) {
671 if (buf[i] != (pos & 0xFF)) {
672 printf("read-mismatch: actual %d, expecting %d, at %"PRId64"\n",
673 (int)buf[i], (int)(pos & 0xFF), pos);
674 break;
675 }
676 pos++;
677 }
678 }
679
680 read_len += ret;
681 }
682 printf("read: %"PRId64"\n", read_len);
683
684 ret = ffurl_read(h, buf, 1);
685 printf("read: %d\n", ret);
686
687 /*
688 * test read error
689 */
690 ffurl_close(h);
691 av_dict_set_int(&opts, "async-test-read-error", -10000, 0);
692 ret = ffurl_open_whitelist(&h, "async:async-test:", AVIO_FLAG_READ,
693 NULL, &opts, NULL, NULL, NULL);
694 printf("open: %d\n", ret);
695
696 ret = ffurl_read(h, buf, 1);
697 printf("read: %d\n", ret);
698
699 fail:
700 av_dict_free(&opts);
701 ffurl_close(h);
702 return 0;
703 }
704
705 #endif
706