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 AVFifo *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_alloc2(capacity + read_back_capacity, 1, 0);
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_freep2(&ring->fifo);
97 }
98
ring_reset(RingBuffer *ring)99 static void ring_reset(RingBuffer *ring)
100 {
101 av_fifo_reset2(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_can_read(ring->fifo) - ring->read_pos;
108 }
109
ring_space(RingBuffer *ring)110 static int ring_space(RingBuffer *ring)
111 {
112 return av_fifo_can_write(ring->fifo);
113 }
114
ring_read(RingBuffer *ring, void *dest, int buf_size)115 static int ring_read(RingBuffer *ring, void *dest, int buf_size)
116 {
117 int ret = 0;
118
119 av_assert2(buf_size <= ring_size(ring));
120 if (dest)
121 ret = av_fifo_peek(ring->fifo, dest, buf_size, ring->read_pos);
122 ring->read_pos += buf_size;
123
124 if (ring->read_pos > ring->read_back_capacity) {
125 av_fifo_drain2(ring->fifo, ring->read_pos - ring->read_back_capacity);
126 ring->read_pos = ring->read_back_capacity;
127 }
128
129 return ret;
130 }
131
wrapped_url_read(void *src, void *dst, size_t *size)132 static int wrapped_url_read(void *src, void *dst, size_t *size)
133 {
134 URLContext *h = src;
135 Context *c = h->priv_data;
136 int ret;
137
138 ret = ffurl_read(c->inner, dst, *size);
139 *size = ret > 0 ? ret : 0;
140 c->inner_io_error = ret < 0 ? ret : 0;
141
142 return c->inner_io_error;
143 }
144
ring_write(RingBuffer *ring, URLContext *h, size_t size)145 static int ring_write(RingBuffer *ring, URLContext *h, size_t size)
146 {
147 int ret;
148
149 av_assert2(size <= ring_space(ring));
150 ret = av_fifo_write_from_cb(ring->fifo, wrapped_url_read, h, &size);
151 if (ret < 0)
152 return ret;
153
154 return size;
155 }
156
ring_size_of_read_back(RingBuffer *ring)157 static int ring_size_of_read_back(RingBuffer *ring)
158 {
159 return ring->read_pos;
160 }
161
ring_drain(RingBuffer *ring, int offset)162 static int ring_drain(RingBuffer *ring, int offset)
163 {
164 av_assert2(offset >= -ring_size_of_read_back(ring));
165 av_assert2(offset <= ring_size(ring));
166 ring->read_pos += offset;
167 return 0;
168 }
169
async_check_interrupt(void *arg)170 static int async_check_interrupt(void *arg)
171 {
172 URLContext *h = arg;
173 Context *c = h->priv_data;
174
175 if (c->abort_request)
176 return 1;
177
178 if (ff_check_interrupt(&c->interrupt_callback))
179 c->abort_request = 1;
180
181 return c->abort_request;
182 }
183
async_buffer_task(void *arg)184 static void *async_buffer_task(void *arg)
185 {
186 URLContext *h = arg;
187 Context *c = h->priv_data;
188 RingBuffer *ring = &c->ring;
189 int ret = 0;
190 int64_t seek_ret;
191
192 while (1) {
193 int fifo_space, to_copy;
194
195 pthread_mutex_lock(&c->mutex);
196 if (async_check_interrupt(h)) {
197 c->io_eof_reached = 1;
198 c->io_error = AVERROR_EXIT;
199 pthread_cond_signal(&c->cond_wakeup_main);
200 pthread_mutex_unlock(&c->mutex);
201 break;
202 }
203
204 if (c->seek_request) {
205 seek_ret = ffurl_seek(c->inner, c->seek_pos, c->seek_whence);
206 if (seek_ret >= 0) {
207 c->io_eof_reached = 0;
208 c->io_error = 0;
209 ring_reset(ring);
210 }
211
212 c->seek_completed = 1;
213 c->seek_ret = seek_ret;
214 c->seek_request = 0;
215
216
217 pthread_cond_signal(&c->cond_wakeup_main);
218 pthread_mutex_unlock(&c->mutex);
219 continue;
220 }
221
222 fifo_space = ring_space(ring);
223 if (c->io_eof_reached || fifo_space <= 0) {
224 pthread_cond_signal(&c->cond_wakeup_main);
225 pthread_cond_wait(&c->cond_wakeup_background, &c->mutex);
226 pthread_mutex_unlock(&c->mutex);
227 continue;
228 }
229 pthread_mutex_unlock(&c->mutex);
230
231 to_copy = FFMIN(4096, fifo_space);
232 ret = ring_write(ring, h, to_copy);
233
234 pthread_mutex_lock(&c->mutex);
235 if (ret <= 0) {
236 c->io_eof_reached = 1;
237 if (c->inner_io_error < 0)
238 c->io_error = c->inner_io_error;
239 }
240
241 pthread_cond_signal(&c->cond_wakeup_main);
242 pthread_mutex_unlock(&c->mutex);
243 }
244
245 return NULL;
246 }
247
async_open(URLContext *h, const char *arg, int flags, AVDictionary **options)248 static int async_open(URLContext *h, const char *arg, int flags, AVDictionary **options)
249 {
250 Context *c = h->priv_data;
251 int ret;
252 AVIOInterruptCB interrupt_callback = {.callback = async_check_interrupt, .opaque = h};
253
254 av_strstart(arg, "async:", &arg);
255
256 ret = ring_init(&c->ring, BUFFER_CAPACITY, READ_BACK_CAPACITY);
257 if (ret < 0)
258 goto fifo_fail;
259
260 /* wrap interrupt callback */
261 c->interrupt_callback = h->interrupt_callback;
262 ret = ffurl_open_whitelist(&c->inner, arg, flags, &interrupt_callback, options, h->protocol_whitelist, h->protocol_blacklist, h);
263 if (ret != 0) {
264 av_log(h, AV_LOG_ERROR, "ffurl_open failed : %s, %s\n", av_err2str(ret), arg);
265 goto url_fail;
266 }
267
268 c->logical_size = ffurl_size(c->inner);
269 h->is_streamed = c->inner->is_streamed;
270
271 ret = pthread_mutex_init(&c->mutex, NULL);
272 if (ret != 0) {
273 ret = AVERROR(ret);
274 av_log(h, AV_LOG_ERROR, "pthread_mutex_init failed : %s\n", av_err2str(ret));
275 goto mutex_fail;
276 }
277
278 ret = pthread_cond_init(&c->cond_wakeup_main, NULL);
279 if (ret != 0) {
280 ret = AVERROR(ret);
281 av_log(h, AV_LOG_ERROR, "pthread_cond_init failed : %s\n", av_err2str(ret));
282 goto cond_wakeup_main_fail;
283 }
284
285 ret = pthread_cond_init(&c->cond_wakeup_background, NULL);
286 if (ret != 0) {
287 ret = AVERROR(ret);
288 av_log(h, AV_LOG_ERROR, "pthread_cond_init failed : %s\n", av_err2str(ret));
289 goto cond_wakeup_background_fail;
290 }
291
292 ret = pthread_create(&c->async_buffer_thread, NULL, async_buffer_task, h);
293 if (ret) {
294 ret = AVERROR(ret);
295 av_log(h, AV_LOG_ERROR, "pthread_create failed : %s\n", av_err2str(ret));
296 goto thread_fail;
297 }
298
299 return 0;
300
301 thread_fail:
302 pthread_cond_destroy(&c->cond_wakeup_background);
303 cond_wakeup_background_fail:
304 pthread_cond_destroy(&c->cond_wakeup_main);
305 cond_wakeup_main_fail:
306 pthread_mutex_destroy(&c->mutex);
307 mutex_fail:
308 ffurl_closep(&c->inner);
309 url_fail:
310 ring_destroy(&c->ring);
311 fifo_fail:
312 return ret;
313 }
314
async_close(URLContext *h)315 static int async_close(URLContext *h)
316 {
317 Context *c = h->priv_data;
318 int ret;
319
320 pthread_mutex_lock(&c->mutex);
321 c->abort_request = 1;
322 pthread_cond_signal(&c->cond_wakeup_background);
323 pthread_mutex_unlock(&c->mutex);
324
325 ret = pthread_join(c->async_buffer_thread, NULL);
326 if (ret != 0)
327 av_log(h, AV_LOG_ERROR, "pthread_join(): %s\n", av_err2str(ret));
328
329 pthread_cond_destroy(&c->cond_wakeup_background);
330 pthread_cond_destroy(&c->cond_wakeup_main);
331 pthread_mutex_destroy(&c->mutex);
332 ffurl_closep(&c->inner);
333 ring_destroy(&c->ring);
334
335 return 0;
336 }
337
async_read_internal(URLContext *h, void *dest, int size)338 static int async_read_internal(URLContext *h, void *dest, int size)
339 {
340 Context *c = h->priv_data;
341 RingBuffer *ring = &c->ring;
342 int read_complete = !dest;
343 int to_read = size;
344 int ret = 0;
345
346 pthread_mutex_lock(&c->mutex);
347
348 while (to_read > 0) {
349 int fifo_size, to_copy;
350 if (async_check_interrupt(h)) {
351 ret = AVERROR_EXIT;
352 break;
353 }
354 fifo_size = ring_size(ring);
355 to_copy = FFMIN(to_read, fifo_size);
356 if (to_copy > 0) {
357 ring_read(ring, dest, to_copy);
358 if (dest)
359 dest = (uint8_t *)dest + to_copy;
360 c->logical_pos += to_copy;
361 to_read -= to_copy;
362 ret = size - to_read;
363
364 if (to_read <= 0 || !read_complete)
365 break;
366 } else if (c->io_eof_reached) {
367 if (ret <= 0) {
368 if (c->io_error)
369 ret = c->io_error;
370 else
371 ret = AVERROR_EOF;
372 }
373 break;
374 }
375 pthread_cond_signal(&c->cond_wakeup_background);
376 pthread_cond_wait(&c->cond_wakeup_main, &c->mutex);
377 }
378
379 pthread_cond_signal(&c->cond_wakeup_background);
380 pthread_mutex_unlock(&c->mutex);
381
382 return ret;
383 }
384
async_read(URLContext *h, unsigned char *buf, int size)385 static int async_read(URLContext *h, unsigned char *buf, int size)
386 {
387 return async_read_internal(h, buf, size);
388 }
389
async_seek(URLContext *h, int64_t pos, int whence)390 static int64_t async_seek(URLContext *h, int64_t pos, int whence)
391 {
392 Context *c = h->priv_data;
393 RingBuffer *ring = &c->ring;
394 int64_t ret;
395 int64_t new_logical_pos;
396 int fifo_size;
397 int fifo_size_of_read_back;
398
399 if (whence == AVSEEK_SIZE) {
400 av_log(h, AV_LOG_TRACE, "async_seek: AVSEEK_SIZE: %"PRId64"\n", (int64_t)c->logical_size);
401 return c->logical_size;
402 } else if (whence == SEEK_CUR) {
403 av_log(h, AV_LOG_TRACE, "async_seek: %"PRId64"\n", pos);
404 new_logical_pos = pos + c->logical_pos;
405 } else if (whence == SEEK_SET){
406 av_log(h, AV_LOG_TRACE, "async_seek: %"PRId64"\n", pos);
407 new_logical_pos = pos;
408 } else {
409 return AVERROR(EINVAL);
410 }
411 if (new_logical_pos < 0)
412 return AVERROR(EINVAL);
413
414 fifo_size = ring_size(ring);
415 fifo_size_of_read_back = ring_size_of_read_back(ring);
416 if (new_logical_pos == c->logical_pos) {
417 /* current position */
418 return c->logical_pos;
419 } else if ((new_logical_pos >= (c->logical_pos - fifo_size_of_read_back)) &&
420 (new_logical_pos < (c->logical_pos + fifo_size + SHORT_SEEK_THRESHOLD))) {
421 int pos_delta = (int)(new_logical_pos - c->logical_pos);
422 /* fast seek */
423 av_log(h, AV_LOG_TRACE, "async_seek: fask_seek %"PRId64" from %d dist:%d/%d\n",
424 new_logical_pos, (int)c->logical_pos,
425 (int)(new_logical_pos - c->logical_pos), fifo_size);
426
427 if (pos_delta > 0) {
428 // fast seek forwards
429 async_read_internal(h, NULL, pos_delta);
430 } else {
431 // fast seek backwards
432 ring_drain(ring, pos_delta);
433 c->logical_pos = new_logical_pos;
434 }
435
436 return c->logical_pos;
437 } else if (c->logical_size <= 0) {
438 /* can not seek */
439 return AVERROR(EINVAL);
440 } else if (new_logical_pos > c->logical_size) {
441 /* beyond end */
442 return AVERROR(EINVAL);
443 }
444
445 pthread_mutex_lock(&c->mutex);
446
447 c->seek_request = 1;
448 c->seek_pos = new_logical_pos;
449 c->seek_whence = SEEK_SET;
450 c->seek_completed = 0;
451 c->seek_ret = 0;
452
453 while (1) {
454 if (async_check_interrupt(h)) {
455 ret = AVERROR_EXIT;
456 break;
457 }
458 if (c->seek_completed) {
459 if (c->seek_ret >= 0)
460 c->logical_pos = c->seek_ret;
461 ret = c->seek_ret;
462 break;
463 }
464 pthread_cond_signal(&c->cond_wakeup_background);
465 pthread_cond_wait(&c->cond_wakeup_main, &c->mutex);
466 }
467
468 pthread_mutex_unlock(&c->mutex);
469
470 return ret;
471 }
472
473 #define OFFSET(x) offsetof(Context, x)
474 #define D AV_OPT_FLAG_DECODING_PARAM
475
476 static const AVOption options[] = {
477 {NULL},
478 };
479
480 #undef D
481 #undef OFFSET
482
483 static const AVClass async_context_class = {
484 .class_name = "Async",
485 .item_name = av_default_item_name,
486 .option = options,
487 .version = LIBAVUTIL_VERSION_INT,
488 };
489
490 const URLProtocol ff_async_protocol = {
491 .name = "async",
492 .url_open2 = async_open,
493 .url_read = async_read,
494 .url_seek = async_seek,
495 .url_close = async_close,
496 .priv_data_size = sizeof(Context),
497 .priv_data_class = &async_context_class,
498 };
499
500 #if 0
501
502 #define TEST_SEEK_POS (1536)
503 #define TEST_STREAM_SIZE (2048)
504
505 typedef struct TestContext {
506 AVClass *class;
507 int64_t logical_pos;
508 int64_t logical_size;
509
510 /* options */
511 int opt_read_error;
512 } TestContext;
513
514 static int async_test_open(URLContext *h, const char *arg, int flags, AVDictionary **options)
515 {
516 TestContext *c = h->priv_data;
517 c->logical_pos = 0;
518 c->logical_size = TEST_STREAM_SIZE;
519 return 0;
520 }
521
522 static int async_test_close(URLContext *h)
523 {
524 return 0;
525 }
526
527 static int async_test_read(URLContext *h, unsigned char *buf, int size)
528 {
529 TestContext *c = h->priv_data;
530 int i;
531 int read_len = 0;
532
533 if (c->opt_read_error)
534 return c->opt_read_error;
535
536 if (c->logical_pos >= c->logical_size)
537 return AVERROR_EOF;
538
539 for (i = 0; i < size; ++i) {
540 buf[i] = c->logical_pos & 0xFF;
541
542 c->logical_pos++;
543 read_len++;
544
545 if (c->logical_pos >= c->logical_size)
546 break;
547 }
548
549 return read_len;
550 }
551
552 static int64_t async_test_seek(URLContext *h, int64_t pos, int whence)
553 {
554 TestContext *c = h->priv_data;
555 int64_t new_logical_pos;
556
557 if (whence == AVSEEK_SIZE) {
558 return c->logical_size;
559 } else if (whence == SEEK_CUR) {
560 new_logical_pos = pos + c->logical_pos;
561 } else if (whence == SEEK_SET){
562 new_logical_pos = pos;
563 } else {
564 return AVERROR(EINVAL);
565 }
566 if (new_logical_pos < 0)
567 return AVERROR(EINVAL);
568
569 c->logical_pos = new_logical_pos;
570 return new_logical_pos;
571 }
572
573 #define OFFSET(x) offsetof(TestContext, x)
574 #define D AV_OPT_FLAG_DECODING_PARAM
575
576 static const AVOption async_test_options[] = {
577 { "async-test-read-error", "cause read fail",
578 OFFSET(opt_read_error), AV_OPT_TYPE_INT, { .i64 = 0 }, INT_MIN, INT_MAX, .flags = D },
579 {NULL},
580 };
581
582 #undef D
583 #undef OFFSET
584
585 static const AVClass async_test_context_class = {
586 .class_name = "Async-Test",
587 .item_name = av_default_item_name,
588 .option = async_test_options,
589 .version = LIBAVUTIL_VERSION_INT,
590 };
591
592 const URLProtocol ff_async_test_protocol = {
593 .name = "async-test",
594 .url_open2 = async_test_open,
595 .url_read = async_test_read,
596 .url_seek = async_test_seek,
597 .url_close = async_test_close,
598 .priv_data_size = sizeof(TestContext),
599 .priv_data_class = &async_test_context_class,
600 };
601
602 int main(void)
603 {
604 URLContext *h = NULL;
605 int i;
606 int ret;
607 int64_t size;
608 int64_t pos;
609 int64_t read_len;
610 unsigned char buf[4096];
611 AVDictionary *opts = NULL;
612
613 ffurl_register_protocol(&ff_async_protocol);
614 ffurl_register_protocol(&ff_async_test_protocol);
615
616 /*
617 * test normal read
618 */
619 ret = ffurl_open_whitelist(&h, "async:async-test:", AVIO_FLAG_READ,
620 NULL, NULL, NULL, NULL, NULL);
621 printf("open: %d\n", ret);
622
623 size = ffurl_size(h);
624 printf("size: %"PRId64"\n", size);
625
626 pos = ffurl_seek(h, 0, SEEK_CUR);
627 read_len = 0;
628 while (1) {
629 ret = ffurl_read(h, buf, sizeof(buf));
630 if (ret == AVERROR_EOF) {
631 printf("read-error: AVERROR_EOF at %"PRId64"\n", ffurl_seek(h, 0, SEEK_CUR));
632 break;
633 }
634 else if (ret == 0)
635 break;
636 else if (ret < 0) {
637 printf("read-error: %d at %"PRId64"\n", ret, ffurl_seek(h, 0, SEEK_CUR));
638 goto fail;
639 } else {
640 for (i = 0; i < ret; ++i) {
641 if (buf[i] != (pos & 0xFF)) {
642 printf("read-mismatch: actual %d, expecting %d, at %"PRId64"\n",
643 (int)buf[i], (int)(pos & 0xFF), pos);
644 break;
645 }
646 pos++;
647 }
648 }
649
650 read_len += ret;
651 }
652 printf("read: %"PRId64"\n", read_len);
653
654 /*
655 * test normal seek
656 */
657 ret = ffurl_read(h, buf, 1);
658 printf("read: %d\n", ret);
659
660 pos = ffurl_seek(h, TEST_SEEK_POS, SEEK_SET);
661 printf("seek: %"PRId64"\n", pos);
662
663 read_len = 0;
664 while (1) {
665 ret = ffurl_read(h, buf, sizeof(buf));
666 if (ret == AVERROR_EOF)
667 break;
668 else if (ret == 0)
669 break;
670 else if (ret < 0) {
671 printf("read-error: %d at %"PRId64"\n", ret, ffurl_seek(h, 0, SEEK_CUR));
672 goto fail;
673 } else {
674 for (i = 0; i < ret; ++i) {
675 if (buf[i] != (pos & 0xFF)) {
676 printf("read-mismatch: actual %d, expecting %d, at %"PRId64"\n",
677 (int)buf[i], (int)(pos & 0xFF), pos);
678 break;
679 }
680 pos++;
681 }
682 }
683
684 read_len += ret;
685 }
686 printf("read: %"PRId64"\n", read_len);
687
688 ret = ffurl_read(h, buf, 1);
689 printf("read: %d\n", ret);
690
691 /*
692 * test read error
693 */
694 ffurl_close(h);
695 av_dict_set_int(&opts, "async-test-read-error", -10000, 0);
696 ret = ffurl_open_whitelist(&h, "async:async-test:", AVIO_FLAG_READ,
697 NULL, &opts, NULL, NULL, NULL);
698 printf("open: %d\n", ret);
699
700 ret = ffurl_read(h, buf, 1);
701 printf("read: %d\n", ret);
702
703 fail:
704 av_dict_free(&opts);
705 ffurl_close(h);
706 return 0;
707 }
708
709 #endif
710