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mpv/stream/cache.c

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/*
* 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 1
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <errno.h>
#include <assert.h>
#include <libavutil/common.h>
#include "config.h"
#include "osdep/shmem.h"
#include "osdep/timer.h"
#include "core/mp_msg.h"
#include "stream.h"
#include "core/mp_common.h"
// Note: (cache_vars_t*)(cache->priv)->cache == cache
typedef struct {
stream_t *cache; // wrapper stream, used by demuxer etc.
stream_t *stream; // "real" stream, used to read from the source media
unsigned int cache_pid;
// 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
pid_t ppid; // parent PID to detect killed parent
// 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
volatile int control;
volatile uint64_t control_uint_arg;
volatile double control_double_arg;
volatile struct stream_lang_req control_lang_arg;
volatile struct stream_dvd_info_req control_dvd_info_arg;
volatile int control_res;
volatile double stream_time_length;
volatile double stream_time_pos;
volatile double stream_start_time;
volatile int idle;
} cache_vars_t;
static void cache_wakeup(stream_t *stream)
{
cache_vars_t *s = stream->priv;
// signal process to wake up immediately
kill(s->cache_pid, SIGUSR1);
}
// Runs in the forked process
static void cache_flush(cache_vars_t *s)
{
s->offset = s->min_filepos = s->max_filepos = s->read_filepos; // drop cache content :(
}
// Runs in the main process
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;
}
// Runs in the forked process
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_unbuffered(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_unbuffered(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_unbuffered(s->stream, &s->buffer[pos], space);
s->eof = !len;
s->max_filepos += len;
if (pos + len >= s->buffer_size)
s->offset += s->buffer_size; // wrap...
return len;
}
// Runs in the forked process
static int cache_execute_control(cache_vars_t *s)
{
double double_res;
unsigned uint_res;
uint64_t uint64_res;
int needs_flush = 0;
static double 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 (mp_time_sec() - last > 0.099) {
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 (s->stream->control(s->stream, STREAM_CTRL_GET_START_TIME,
&pos) == STREAM_OK)
s->stream_start_time = pos;
else
s->stream_start_time = MP_NOPTS_VALUE;
// 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;
}
last = mp_time_sec();
}
if (s->control == -1)
return 1;
switch (s->control) {
case STREAM_CTRL_SEEK_TO_TIME:
needs_flush = 1;
case STREAM_CTRL_GET_CURRENT_TIME:
case STREAM_CTRL_GET_ASPECT_RATIO:
case STREAM_CTRL_GET_START_TIME:
case STREAM_CTRL_GET_CHAPTER_TIME:
double_res = s->control_double_arg;
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_TITLES:
case STREAM_CTRL_GET_NUM_CHAPTERS:
case STREAM_CTRL_GET_CURRENT_TITLE:
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_SIZE:
s->control_res = s->stream->control(s->stream, s->control, &uint64_res);
s->control_uint_arg = uint64_res;
break;
case STREAM_CTRL_GET_LANG:
s->control_res = s->stream->control(s->stream, s->control,
(void *)&s->control_lang_arg);
break;
case STREAM_CTRL_GET_DVD_INFO:
s->control_res = s->stream->control(s->stream, s->control,
(void *)&s->control_dvd_info_arg);
break;
case STREAM_CTRL_MANAGES_TIMELINE:
s->control_res = s->stream->control(s->stream, s->control, NULL);
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)
{
return shmem_alloc(size);
}
static void shared_free(void *ptr, int64_t size)
{
shmem_free(ptr, size);
}
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 < 32)
num = 32;
//64kb 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;
s->ppid = getpid();
return s;
}
static void cache_uninit(stream_t *s)
{
cache_vars_t *c = s->priv;
if (c->cache_pid) {
kill(c->cache_pid, SIGKILL);
waitpid(c->cache_pid, NULL, 0);
c->cache_pid = 0;
}
if (!c)
return;
shared_free(c->buffer, c->buffer_size);
c->buffer = NULL;
c->stream = NULL;
shared_free(c, sizeof(cache_vars_t));
s->priv = NULL;
}
static void exit_sighandler(int x)
{
// close stream
exit(0);
}
static void dummy_sighandler(int x)
{
}
/**
* Main loop of the cache process or thread.
*/
static void cache_mainloop(cache_vars_t *s)
{
int sleep_count = 0;
struct sigaction sa = {
.sa_handler = SIG_IGN
};
sigaction(SIGUSR1, &sa, NULL);
do {
if (!cache_fill(s)) {
s->idle = 1;
// 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);
if (sleep_count < INITIAL_FILL_USLEEP_COUNT) {
sleep_count++;
mp_sleep_us(INITIAL_FILL_USLEEP_TIME);
} else
mp_sleep_us(FILL_USLEEP_TIME); // idle
sa.sa_handler = SIG_IGN;
sigaction(SIGUSR1, &sa, NULL);
} else {
sleep_count = 0;
s->idle = 0;
}
} while (cache_execute_control(s));
}
static int cache_fill_buffer(struct stream *stream, char *buffer, int max_len)
{
cache_vars_t *c = stream->priv;
assert(c->cache_pid);
if (stream->pos != c->read_filepos)
mp_msg(MSGT_CACHE, MSGL_ERR,
"!!! read_filepos differs!!! report this bug...\n");
return cache_read(c, buffer, max_len);
}
static int cache_seek(stream_t *stream, int64_t pos)
{
cache_vars_t *s = stream->priv;
int64_t newpos;
assert(s->cache_pid);
// 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);
return 1;
}
static int cache_control(stream_t *stream, int cmd, void *arg)
{
int sleep_count = 0;
int pos_change = 0;
cache_vars_t *s = stream->priv;
switch (cmd) {
case STREAM_CTRL_GET_CACHE_SIZE:
*(int64_t *)arg = s->buffer_size;
return STREAM_OK;
case STREAM_CTRL_GET_CACHE_FILL:
*(int64_t *)arg = s->max_filepos - s->read_filepos;
return STREAM_OK;
case STREAM_CTRL_GET_CACHE_IDLE:
*(int *)arg = s->idle;
return STREAM_OK;
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_START_TIME:
*(double *)arg = s->stream_start_time;
return s->stream_start_time !=
MP_NOPTS_VALUE ? STREAM_OK : STREAM_UNSUPPORTED;
case STREAM_CTRL_GET_CHAPTER_TIME:
s->control_double_arg = *(double *)arg;
s->control = cmd;
break;
case STREAM_CTRL_GET_LANG:
s->control_lang_arg = *(struct stream_lang_req *)arg;
case STREAM_CTRL_GET_DVD_INFO:
s->control_dvd_info_arg = *(struct stream_dvd_info_req *)arg;
case STREAM_CTRL_GET_NUM_TITLES:
case STREAM_CTRL_GET_NUM_CHAPTERS:
case STREAM_CTRL_GET_CURRENT_TITLE:
case STREAM_CTRL_GET_CURRENT_CHAPTER:
case STREAM_CTRL_GET_ASPECT_RATIO:
case STREAM_CTRL_GET_NUM_ANGLES:
case STREAM_CTRL_GET_ANGLE:
case STREAM_CTRL_GET_SIZE:
case STREAM_CTRL_MANAGES_TIMELINE:
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:
case STREAM_CTRL_GET_START_TIME:
case STREAM_CTRL_GET_CHAPTER_TIME:
*(double *)arg = s->control_double_arg;
break;
case STREAM_CTRL_GET_NUM_TITLES:
case STREAM_CTRL_GET_NUM_CHAPTERS:
case STREAM_CTRL_GET_CURRENT_TITLE:
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_SIZE:
*(uint64_t *)arg = s->control_uint_arg;
break;
case STREAM_CTRL_GET_LANG:
*(struct stream_lang_req *)arg = s->control_lang_arg;
break;
case STREAM_CTRL_GET_DVD_INFO:
*(struct stream_dvd_info_req *)arg = s->control_dvd_info_arg;
break;
case STREAM_CTRL_MANAGES_TIMELINE:
break;
}
return s->control_res;
}
// return 1 on success, 0 if the function was interrupted and -1 on error, or
// if the cache is disabled
int stream_cache_init(stream_t *cache, stream_t *stream, int64_t size,
int64_t min, int64_t seek_limit)
{
if (size < 0)
size = stream->cache_size * 1024;
if (!size)
return -1;
mp_tmsg(MSGT_NETWORK, MSGL_INFO, "Cache size set to %" PRId64 " KiB\n",
size / 1024);
int ss = stream->sector_size ? stream->sector_size : STREAM_BUFFER_SIZE;
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;
cache->priv = s;
s->cache = cache;
s->stream = stream; // callback
s->seek_limit = seek_limit;
cache->seek = cache_seek;
cache->fill_buffer = cache_fill_buffer;
cache->control = cache_control;
cache->close = cache_uninit;
//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;
pid_t child_pid = fork();
if (child_pid) {
if (child_pid == (pid_t)-1)
child_pid = 0;
if (!child_pid) {
mp_msg(MSGT_CACHE, MSGL_ERR,
"Starting cache process/thread failed: %s.\n",
strerror(errno));
return -1;
}
s->cache_pid = child_pid;
// 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))
return 0;
}
mp_msg(MSGT_CACHE, MSGL_STATUS, "\n");
return 1; // parent exits
}
signal(SIGTERM, exit_sighandler); // kill
cache_mainloop(s);
// make sure forked code never leaves this function
exit(0);
}
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