summaryrefslogtreecommitdiffstats
path: root/stream/cache2.c
blob: 9161027ee3b6b66478f2341ac120de7cad944d18 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
/*
 * This file is part of MPlayer.
 *
 * MPlayer is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * MPlayer is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with MPlayer; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

// Initial draft of my new cache system...
// Note it runs in 2 processes (using fork()), but doesn't require locking!!
// TODO: seeking, data consistency checking

#define READ_SLEEP_TIME 10
// These defines are used to reduce the cost of many successive
// seeks (e.g. when a file has no index) by spinning quickly at first.
#define INITIAL_FILL_USLEEP_TIME 1000
#define INITIAL_FILL_USLEEP_COUNT 10
#define FILL_USLEEP_TIME 50000
#define PREFILL_SLEEP_TIME 200
#define CONTROL_SLEEP_TIME 0

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>

#include <libavutil/common.h>

#include "config.h"

#include "osdep/shmem.h"
#include "osdep/timer.h"
#if defined(__MINGW32__)
#include <windows.h>
static void ThreadProc( void *s );
#elif defined(PTHREAD_CACHE)
#include <pthread.h>
static void *ThreadProc(void *s);
#else
#include <sys/wait.h>
#define FORKED_CACHE 1
#endif
#ifndef FORKED_CACHE
#define FORKED_CACHE 0
#endif

#include "mp_msg.h"

#include "stream.h"
#include "cache2.h"
#include "mpcommon.h"

typedef struct {
  // constats:
  unsigned char *buffer;      // base pointer of the allocated buffer memory
  int64_t buffer_size; // size of the allocated buffer memory
  int sector_size; // size of a single sector (2048/2324)
  int64_t back_size;   // we should keep back_size amount of old bytes for backward seek
  int64_t fill_limit;  // we should fill buffer only if space>=fill_limit
  int64_t seek_limit;  // keep filling cache if distance is less that seek limit
#if FORKED_CACHE
  pid_t ppid; // parent PID to detect killed parent
#endif
  // filler's pointers:
  int eof;
  int64_t min_filepos; // buffer contain only a part of the file, from min-max pos
  int64_t max_filepos;
  int64_t offset;      // filepos <-> bufferpos  offset value (filepos of the buffer's first byte)
  // reader's pointers:
  int64_t read_filepos;
  // commands/locking:
//  int seek_lock;   // 1 if we will seek/reset buffer, 2 if we are ready for cmd
//  int fifo_flag;  // 1 if we should use FIFO to notice cache about buffer reads.
  // callback
  stream_t* stream;
  volatile int control;
  volatile unsigned control_uint_arg;
  volatile double control_double_arg;
  volatile struct stream_lang_req control_lang_arg;
  volatile int control_res;
  volatile double stream_time_length;
  volatile double stream_time_pos;
} cache_vars_t;

static void cache_wakeup(stream_t *s)
{
#if FORKED_CACHE
  // signal process to wake up immediately
  kill(s->cache_pid, SIGUSR1);
#endif
}

static void cache_flush(cache_vars_t *s)
{
  s->offset= // FIXME!?
  s->min_filepos=s->max_filepos=s->read_filepos; // drop cache content :(
}

static int cache_read(cache_vars_t *s, unsigned char *buf, int size)
{
  int total=0;
  int sleep_count = 0;
  int64_t last_max = s->max_filepos;
  while(size>0){
    int64_t pos,newb,len;

  //printf("CACHE2_READ: 0x%X <= 0x%X <= 0x%X  \n",s->min_filepos,s->read_filepos,s->max_filepos);

    if(s->read_filepos>=s->max_filepos || s->read_filepos<s->min_filepos){
	// eof?
	if(s->eof) break;
	if (s->max_filepos == last_max) {
	    if (sleep_count++ == 10)
	        mp_msg(MSGT_CACHE, MSGL_WARN, "Cache empty, consider increasing -cache and/or -cache-min. [performance issue]\n");
	} else {
	    last_max = s->max_filepos;
	    sleep_count = 0;
	}
	// waiting for buffer fill...
	if (stream_check_interrupt(READ_SLEEP_TIME)) {
	    s->eof = 1;
	    break;
	}
	continue; // try again...
    }
    sleep_count = 0;

    newb=s->max_filepos-s->read_filepos; // new bytes in the buffer

//    printf("*** newb: %d bytes ***\n",newb);

    pos=s->read_filepos - s->offset;
    if(pos<0) pos+=s->buffer_size; else
    if(pos>=s->buffer_size) pos-=s->buffer_size;

    if(newb>s->buffer_size-pos) newb=s->buffer_size-pos; // handle wrap...
    if(newb>size) newb=size;

    // check:
    if(s->read_filepos<s->min_filepos) mp_msg(MSGT_CACHE,MSGL_ERR,"Ehh. s->read_filepos<s->min_filepos !!! Report bug...\n");

    // len=write(mem,newb)
    //printf("Buffer read: %d bytes\n",newb);
    memcpy(buf,&s->buffer[pos],newb);
    buf+=newb;
    len=newb;
    // ...

    s->read_filepos+=len;
    size-=len;
    total+=len;

  }
  return total;
}

static int cache_fill(cache_vars_t *s)
{
  int64_t back,back2,newb,space,len,pos;
  int64_t read=s->read_filepos;
  int read_chunk;
  int wraparound_copy = 0;

  if(read<s->min_filepos || read>s->max_filepos){
      // seek...
      mp_msg(MSGT_CACHE,MSGL_DBG2,"Out of boundaries... seeking to 0x%"PRIX64"  \n",read);
      // drop cache contents only if seeking backward or too much fwd.
      // This is also done for on-disk files, since it loses the backseek cache.
      // That in turn can cause major bandwidth increase and performance
      // issues with e.g. mov or badly interleaved files
      if(read<s->min_filepos || read>=s->max_filepos+s->seek_limit)
      {
        cache_flush(s);
        if(s->stream->eof) stream_reset(s->stream);
        stream_seek_internal(s->stream,read);
        mp_msg(MSGT_CACHE,MSGL_DBG2,"Seek done. new pos: 0x%"PRIX64"  \n",(int64_t)stream_tell(s->stream));
      }
  }

  // calc number of back-bytes:
  back=read - s->min_filepos;
  if(back<0) back=0; // strange...
  if(back>s->back_size) back=s->back_size;

  // calc number of new bytes:
  newb=s->max_filepos - read;
  if(newb<0) newb=0; // strange...

  // calc free buffer space:
  space=s->buffer_size - (newb+back);

  // calc bufferpos:
  pos=s->max_filepos - s->offset;
  if(pos>=s->buffer_size) pos-=s->buffer_size; // wrap-around

  if(space<s->fill_limit){
//    printf("Buffer is full (%d bytes free, limit: %d)\n",space,s->fill_limit);
    return 0; // no fill...
  }

//  printf("### read=0x%X  back=%d  newb=%d  space=%d  pos=%d\n",read,back,newb,space,pos);

  // try to avoid wrap-around. If not possible due to sector size
  // do an extra copy.
  if(space>s->buffer_size-pos) {
    if (s->buffer_size-pos >= s->sector_size) {
      space=s->buffer_size-pos;
    } else {
      space = s->sector_size;
      wraparound_copy = 1;
    }
  }

  // limit one-time block size
  read_chunk = s->stream->read_chunk;
  if (!read_chunk) read_chunk = 4*s->sector_size;
  space = FFMIN(space, read_chunk);

#if 1
  // back+newb+space <= buffer_size
  back2=s->buffer_size-(space+newb); // max back size
  if(s->min_filepos<(read-back2)) s->min_filepos=read-back2;
#else
  s->min_filepos=read-back; // avoid seeking-back to temp area...
#endif

  if (wraparound_copy) {
    int to_copy;
    len = stream_read_internal(s->stream, s->stream->buffer, space);
    to_copy = FFMIN(len, s->buffer_size-pos);
    memcpy(s->buffer + pos, s->stream->buffer, to_copy);
    memcpy(s->buffer, s->stream->buffer + to_copy, len - to_copy);
  } else
  len = stream_read_internal(s->stream, &s->buffer[pos], space);
  s->eof= !len;

  s->max_filepos+=len;
  if(pos+len>=s->buffer_size){
      // wrap...
      s->offset+=s->buffer_size;
  }

  return len;

}

static int cache_execute_control(cache_vars_t *s) {
  double double_res;
  unsigned uint_res;
  int needs_flush = 0;
  static unsigned last;
  int quit = s->control == -2;
  uint64_t old_pos = s->stream->pos;
  int old_eof = s->stream->eof;
  if (quit || !s->stream->control) {
    s->stream_time_length = 0;
    s->stream_time_pos = MP_NOPTS_VALUE;
    s->control_res = STREAM_UNSUPPORTED;
    s->control = -1;
    return !quit;
  }
  if (GetTimerMS() - last > 99) {
    double len, pos;
    if (s->stream->control(s->stream, STREAM_CTRL_GET_TIME_LENGTH, &len) == STREAM_OK)
      s->stream_time_length = len;
    else
      s->stream_time_length = 0;
    if (s->stream->control(s->stream, STREAM_CTRL_GET_CURRENT_TIME, &pos) == STREAM_OK)
      s->stream_time_pos = pos;
    else
      s->stream_time_pos = MP_NOPTS_VALUE;
#if FORKED_CACHE
    // if parent PID changed, main process was killed -> exit
    if (s->ppid != getppid()) {
      mp_msg(MSGT_CACHE, MSGL_WARN, "Parent process disappeared, exiting cache process.\n");
      return 0;
    }
#endif
    last = GetTimerMS();
  }
  if (s->control == -1) return 1;
  switch (s->control) {
    case STREAM_CTRL_SEEK_TO_TIME:
      needs_flush = 1;
      double_res = s->control_double_arg;
    case STREAM_CTRL_GET_CURRENT_TIME:
    case STREAM_CTRL_GET_ASPECT_RATIO:
      s->control_res = s->stream->control(s->stream, s->control, &double_res);
      s->control_double_arg = double_res;
      break;
    case STREAM_CTRL_SEEK_TO_CHAPTER:
    case STREAM_CTRL_SET_ANGLE:
      needs_flush = 1;
      uint_res = s->control_uint_arg;
    case STREAM_CTRL_GET_NUM_CHAPTERS:
    case STREAM_CTRL_GET_CURRENT_CHAPTER:
    case STREAM_CTRL_GET_NUM_ANGLES:
    case STREAM_CTRL_GET_ANGLE:
      s->control_res = s->stream->control(s->stream, s->control, &uint_res);
      s->control_uint_arg = uint_res;
      break;
    case STREAM_CTRL_GET_LANG:
      s->control_res = s->stream->control(s->stream, s->control, (void *)&s->control_lang_arg);
      break;
    default:
      s->control_res = STREAM_UNSUPPORTED;
      break;
  }
  if (s->control_res == STREAM_OK && needs_flush) {
    s->read_filepos = s->stream->pos;
    s->eof = s->stream->eof;
    cache_flush(s);
  } else if (needs_flush &&
             (old_pos != s->stream->pos || old_eof != s->stream->eof))
    mp_msg(MSGT_STREAM, MSGL_ERR, "STREAM_CTRL changed stream pos but returned error, this is not allowed!\n");
  s->control = -1;
  return 1;
}

static void *shared_alloc(int64_t size) {
#if FORKED_CACHE
    return shmem_alloc(size);
#else
    return malloc(size);
#endif
}

static void shared_free(void *ptr, int64_t size) {
#if FORKED_CACHE
    shmem_free(ptr, size);
#else
    free(ptr);
#endif
}

static cache_vars_t* cache_init(int64_t size,int sector){
  int64_t num;
  cache_vars_t* s=shared_alloc(sizeof(cache_vars_t));
  if(s==NULL) return NULL;

  memset(s,0,sizeof(cache_vars_t));
  num=size/sector;
  if(num < 16){
     num = 16;
  }//32kb min_size
  s->buffer_size=num*sector;
  s->sector_size=sector;
  s->buffer=shared_alloc(s->buffer_size);

  if(s->buffer == NULL){
    shared_free(s, sizeof(cache_vars_t));
    return NULL;
  }

  s->fill_limit=8*sector;
  s->back_size=s->buffer_size/2;
#if FORKED_CACHE
  s->ppid = getpid();
#endif
  return s;
}

void cache_uninit(stream_t *s) {
  cache_vars_t* c = s->cache_data;
  if(s->cache_pid) {
#if !FORKED_CACHE
    cache_do_control(s, -2, NULL);
#else
    kill(s->cache_pid,SIGKILL);
    waitpid(s->cache_pid,NULL,0);
#endif
    s->cache_pid = 0;
  }
  if(!c) return;
  shared_free(c->buffer, c->buffer_size);
  c->buffer = NULL;
  c->stream = NULL;
  shared_free(s->cache_data, sizeof(cache_vars_t));
  s->cache_data = NULL;
}

#if FORKED_CACHE
static void exit_sighandler(int x){
  // close stream
  exit(0);
}

static void dummy_sighandler(int x) {
}
#endif

/**
 * Main loop of the cache process or thread.
 */
static void cache_mainloop(cache_vars_t *s) {
    int sleep_count = 0;
#if FORKED_CACHE
    struct sigaction sa = { .sa_handler = SIG_IGN };
    sigaction(SIGUSR1, &sa, NULL);
#endif
    do {
        if (!cache_fill(s)) {
#if FORKED_CACHE
            // Let signal wake us up, we cannot leave this
            // enabled since we do not handle EINTR in most places.
            // This might need extra code to work on BSD.
            sa.sa_handler = dummy_sighandler;
            sigaction(SIGUSR1, &sa, NULL);
#endif
            if (sleep_count < INITIAL_FILL_USLEEP_COUNT) {
                sleep_count++;
                usec_sleep(INITIAL_FILL_USLEEP_TIME);
            } else
                usec_sleep(FILL_USLEEP_TIME); // idle
#if FORKED_CACHE
            sa.sa_handler = SIG_IGN;
            sigaction(SIGUSR1, &sa, NULL);
#endif
        } else
            sleep_count = 0;
    } while (cache_execute_control(s));
}

int stream_enable_cache_percent(stream_t *stream, int64_t stream_cache_size,
    float stream_cache_min_percent, float stream_cache_seek_min_percent)
{
    return stream_enable_cache(stream, stream_cache_size * 1024,
        stream_cache_size * 1024 * (stream_cache_min_percent / 100.0),
        stream_cache_size * 1024 * (stream_cache_seek_min_percent / 100.0));
}

/**
 * \return 1 on success, 0 if the function was interrupted and -1 on error
 */
int stream_enable_cache(stream_t *stream,int64_t size,int64_t min,int64_t seek_limit){
  int ss = stream->sector_size ? stream->sector_size : STREAM_BUFFER_SIZE;
  int res = -1;
  cache_vars_t* s;

  if (size > SIZE_MAX) {
    mp_msg(MSGT_CACHE, MSGL_FATAL, "Cache size larger than max. allocation size\n");
    return -1;
  }

  s=cache_init(size,ss);
  if(s == NULL) return -1;
  stream->cache_data=s;
  s->stream=stream; // callback
  s->seek_limit=seek_limit;


  //make sure that we won't wait from cache_fill
  //more data than it is allowed to fill
  if (s->seek_limit > s->buffer_size - s->fill_limit ){
     s->seek_limit = s->buffer_size - s->fill_limit;
  }
  if (min > s->buffer_size - s->fill_limit) {
     min = s->buffer_size - s->fill_limit;
  }
  // to make sure we wait for the cache process/thread to be active
  // before continuing
  if (min <= 0)
    min = 1;

#if FORKED_CACHE
  if((stream->cache_pid=fork())){
    if ((pid_t)stream->cache_pid == -1)
      stream->cache_pid = 0;
#else
  {
    stream_t* stream2=malloc(sizeof(stream_t));
    memcpy(stream2,s->stream,sizeof(stream_t));
    s->stream=stream2;
#if defined(__MINGW32__)
    stream->cache_pid = _beginthread( ThreadProc, 0, s );
#else
    {
    pthread_t tid;
    pthread_create(&tid, NULL, ThreadProc, s);
    stream->cache_pid = 1;
    }
#endif
#endif
    if (!stream->cache_pid) {
        mp_msg(MSGT_CACHE, MSGL_ERR,
               "Starting cache process/thread failed: %s.\n", strerror(errno));
        goto err_out;
    }
    // wait until cache is filled at least prefill_init %
    mp_msg(MSGT_CACHE,MSGL_V,"CACHE_PRE_INIT: %"PRId64" [%"PRId64"] %"PRId64"  pre:%"PRId64"  eof:%d  \n",
	s->min_filepos,s->read_filepos,s->max_filepos,min,s->eof);
    while(s->read_filepos<s->min_filepos || s->max_filepos-s->read_filepos<min){
	mp_tmsg(MSGT_CACHE,MSGL_STATUS,"\rCache fill: %5.2f%% (%"PRId64" bytes)   ",
	    100.0*(float)(s->max_filepos-s->read_filepos)/(float)(s->buffer_size),
	    s->max_filepos-s->read_filepos
	);
	if(s->eof) break; // file is smaller than prefill size
	if(stream_check_interrupt(PREFILL_SLEEP_TIME)) {
	  res = 0;
	  goto err_out;
        }
    }
    mp_msg(MSGT_CACHE,MSGL_STATUS,"\n");
    return 1; // parent exits

err_out:
    cache_uninit(stream);
    return res;
  }

#if FORKED_CACHE
  signal(SIGTERM,exit_sighandler); // kill
  cache_mainloop(s);
  // make sure forked code never leaves this function
  exit(0);
#endif
}

#if !FORKED_CACHE
#if defined(__MINGW32__)
static void ThreadProc( void *s ){
  cache_mainloop(s);
  _endthread();
}
#else
static void *ThreadProc( void *s ){
  cache_mainloop(s);
  return NULL;
}
#endif
#endif

int cache_stream_fill_buffer(stream_t *s){
  int len;
  int sector_size;
  if(!s->cache_pid) return stream_fill_buffer(s);

  if(s->pos!=((cache_vars_t*)s->cache_data)->read_filepos) mp_msg(MSGT_CACHE,MSGL_ERR,"!!! read_filepos differs!!! report this bug...\n");
  sector_size = ((cache_vars_t*)s->cache_data)->sector_size;
  if (sector_size > STREAM_MAX_SECTOR_SIZE) {
    mp_msg(MSGT_CACHE, MSGL_ERR, "Sector size %i larger than maximum %i\n", sector_size, STREAM_MAX_SECTOR_SIZE);
    sector_size = STREAM_MAX_SECTOR_SIZE;
  }

  len=cache_read(s->cache_data,s->buffer, sector_size);
  //printf("cache_stream_fill_buffer->read -> %d\n",len);

  if(len<=0){ s->eof=1; s->buf_pos=s->buf_len=0; return 0; }
  s->eof=0;
  s->buf_pos=0;
  s->buf_len=len;
  s->pos+=len;
//  printf("[%d]",len);fflush(stdout);
  return len;

}

int cache_fill_status(stream_t *s) {
  cache_vars_t *cv;
  if (!s || !s->cache_data)
    return -1;
  cv = s->cache_data;
  return (cv->max_filepos-cv->read_filepos)/(cv->buffer_size / 100);
}

int cache_stream_seek_long(stream_t *stream,int64_t pos){
  cache_vars_t* s;
  int64_t newpos;
  if(!stream->cache_pid) return stream_seek_long(stream,pos);

  s=stream->cache_data;
//  s->seek_lock=1;

  mp_msg(MSGT_CACHE,MSGL_DBG2,"CACHE2_SEEK: 0x%"PRIX64" <= 0x%"PRIX64" (0x%"PRIX64") <= 0x%"PRIX64"  \n",s->min_filepos,pos,s->read_filepos,s->max_filepos);

  newpos=pos/s->sector_size; newpos*=s->sector_size; // align
  stream->pos=s->read_filepos=newpos;
  s->eof=0; // !!!!!!!
  cache_wakeup(stream);

  cache_stream_fill_buffer(stream);

  pos-=newpos;
  if(pos>=0 && pos<=stream->buf_len){
    stream->buf_pos=pos; // byte position in sector
    return 1;
  }

//  stream->buf_pos=stream->buf_len=0;
//  return 1;

  mp_msg(MSGT_CACHE,MSGL_V,"cache_stream_seek: WARNING! Can't seek to 0x%"PRIX64" !\n",pos+newpos);
  return 0;
}

int cache_do_control(stream_t *stream, int cmd, void *arg) {
  int sleep_count = 0;
  int pos_change = 0;
  cache_vars_t* s = stream->cache_data;
  switch (cmd) {
    case STREAM_CTRL_SEEK_TO_TIME:
      s->control_double_arg = *(double *)arg;
      s->control = cmd;
      pos_change = 1;
      break;
    case STREAM_CTRL_SEEK_TO_CHAPTER:
    case STREAM_CTRL_SET_ANGLE:
      s->control_uint_arg = *(unsigned *)arg;
      s->control = cmd;
      pos_change = 1;
      break;
    // the core might call these every frame, so cache them...
    case STREAM_CTRL_GET_TIME_LENGTH:
      *(double *)arg = s->stream_time_length;
      return s->stream_time_length ? STREAM_OK : STREAM_UNSUPPORTED;
    case STREAM_CTRL_GET_CURRENT_TIME:
      *(double *)arg = s->stream_time_pos;
      return s->stream_time_pos != MP_NOPTS_VALUE ? STREAM_OK : STREAM_UNSUPPORTED;
    case STREAM_CTRL_GET_LANG:
      s->control_lang_arg = *(struct stream_lang_req *)arg;
    case STREAM_CTRL_GET_NUM_CHAPTERS:
    case STREAM_CTRL_GET_CURRENT_CHAPTER:
    case STREAM_CTRL_GET_ASPECT_RATIO:
    case STREAM_CTRL_GET_NUM_ANGLES:
    case STREAM_CTRL_GET_ANGLE:
    case -2:
      s->control = cmd;
      break;
    default:
      return STREAM_UNSUPPORTED;
  }
  cache_wakeup(stream);
  while (s->control != -1) {
    if (sleep_count++ == 1000)
      mp_msg(MSGT_CACHE, MSGL_WARN, "Cache not responding! [performance issue]\n");
    if (stream_check_interrupt(CONTROL_SLEEP_TIME)) {
      s->eof = 1;
      return STREAM_UNSUPPORTED;
    }
  }
  if (s->control_res != STREAM_OK)
    return s->control_res;
  // We cannot do this on failure, since this would cause the
  // stream position to jump when e.g. STREAM_CTRL_SEEK_TO_TIME
  // is unsupported - but in that case we need the old value
  // to do the fallback seek.
  // This unfortunately can lead to slightly different behaviour
  // with and without cache if the protocol changes pos even
  // when an error happened.
  if (pos_change) {
    stream->pos = s->read_filepos;
    stream->eof = s->eof;
  }
  switch (cmd) {
    case STREAM_CTRL_GET_TIME_LENGTH:
    case STREAM_CTRL_GET_CURRENT_TIME:
    case STREAM_CTRL_GET_ASPECT_RATIO:
      *(double *)arg = s->control_double_arg;
      break;
    case STREAM_CTRL_GET_NUM_CHAPTERS:
    case STREAM_CTRL_GET_CURRENT_CHAPTER:
    case STREAM_CTRL_GET_NUM_ANGLES:
    case STREAM_CTRL_GET_ANGLE:
      *(unsigned *)arg = s->control_uint_arg;
      break;
    case STREAM_CTRL_GET_LANG:
      *(struct stream_lang_req *)arg = s->control_lang_arg;
      break;
  }
  return s->control_res;
}