// Runs in the cache thread
static void cache_execute_control(struct priv *s)
{
uint64_t old_pos = stream_tell(s->stream);
s->control_flush = false;
switch (s->control) {
case STREAM_CTRL_SET_CACHE_SIZE:
s->control_res = resize_cache(s, *(int64_t *)s->control_arg);
break;
default:
s->control_res = stream_control(s->stream, s->control, s->control_arg);
}
bool pos_changed = old_pos != stream_tell(s->stream);
bool ok = s->control_res == STREAM_OK;
if (pos_changed && !ok) {
MP_ERR(s, "STREAM_CTRL changed stream pos but "
"returned error, this is not allowed!\n");
} else if (pos_changed || (ok && control_needs_flush(s->control))) {
MP_VERBOSE(s, "Dropping cache due to control()\n");
s->read_filepos = stream_tell(s->stream);
s->control_flush = true;
cache_drop_contents(s);
}
update_cached_controls(s);
s->control = CACHE_CTRL_NONE;
pthread_cond_signal(&s->wakeup);
}
// This is called both during init and at runtime.
static int resize_cache(struct priv *s, int64_t size)
{
int64_t min_size = FILL_LIMIT * 4;
int64_t max_size = ((size_t)-1) / 4;
int64_t buffer_size = MPMIN(MPMAX(size, min_size), max_size);
unsigned char *buffer = malloc(buffer_size);
struct byte_meta *bm = calloc(buffer_size / BYTE_META_CHUNK_SIZE + 2,
sizeof(struct byte_meta));
if (!buffer || !bm) {
free(buffer);
free(bm);
return STREAM_ERROR;
}
if (s->buffer) {
// Copy & free the old ringbuffer data.
// If the buffer is too small, prefer to copy these regions:
// 1. Data starting from read_filepos, until cache end
size_t read_1 = read_buffer(s, buffer, buffer_size, s->read_filepos);
// 2. then data from before read_filepos until cache start
// (this one needs to be copied to the end of the ringbuffer)
size_t read_2 = 0;
if (s->min_filepos < s->read_filepos) {
size_t copy_len = buffer_size - read_1;
copy_len = MPMIN(copy_len, s->read_filepos - s->min_filepos);
assert(copy_len + read_1 <= buffer_size);
read_2 = read_buffer(s, buffer + buffer_size - copy_len, copy_len,
s->read_filepos - copy_len);
// This shouldn't happen, unless copy_len was computed incorrectly.
assert(read_2 == copy_len);
}
// Set it up such that read_1 is at buffer pos 0, and read_2 wraps
// around below it, so that it is located at the end of the buffer.
s->min_filepos = s->read_filepos - read_2;
s->max_filepos = s->read_filepos + read_1;
s->offset = s->max_filepos - read_1;
} else {
cache_drop_contents(s);
}
free(s->buffer);
free(s->bm);
s->buffer_size = buffer_size;
s->back_size = buffer_size / 2;
s->buffer = buffer;
s->bm = bm;
s->idle = false;
s->eof = false;
//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 - FILL_LIMIT)
s->seek_limit = s->buffer_size - FILL_LIMIT;
return STREAM_OK;
}
// Runs in the cache thread
static void cache_execute_control(struct priv *s)
{
uint64_t old_pos = stream_tell(s->stream);
s->control_res = stream_control(s->stream, s->control, s->control_arg);
s->control_flush = false;
bool pos_changed = old_pos != stream_tell(s->stream);
bool ok = s->control_res == STREAM_OK;
if (pos_changed && !ok) {
mp_msg(MSGT_STREAM, MSGL_ERR, "STREAM_CTRL changed stream pos but "
"returned error, this is not allowed!\n");
} else if (pos_changed || (ok && control_needs_flush(s->control))) {
mp_msg(MSGT_CACHE, MSGL_V, "Dropping cache due to control()\n");
s->read_filepos = stream_tell(s->stream);
s->control_flush = true;
cache_drop_contents(s);
}
s->control = CACHE_CTRL_NONE;
pthread_cond_signal(&s->wakeup);
}
// return 1 on success, 0 if the cache is disabled/not needed, and -1 on error
// or if the cache is disabled
int stream_cache_init(stream_t *cache, stream_t *stream,
struct mp_cache_opts *opts)
{
if (opts->size < 1)
return 0;
struct priv *s = talloc_zero(NULL, struct priv);
s->log = cache->log;
s->eof_pos = -1;
cache_drop_contents(s);
s->seek_limit = opts->seek_min * 1024ULL;
s->back_size = opts->back_buffer * 1024ULL;
int64_t cache_size = opts->size * 1024ULL;
int64_t file_size = stream_get_size(stream);
if (file_size >= 0)
cache_size = MPMIN(cache_size, file_size);
if (resize_cache(s, cache_size) != STREAM_OK) {
MP_ERR(s, "Failed to allocate cache buffer.\n");
talloc_free(s);
return -1;
}
MP_VERBOSE(cache, "Cache size set to %lld KiB (%lld KiB backbuffer)\n",
(long long)(s->buffer_size / 1024),
(long long)(s->back_size / 1024));
pthread_mutex_init(&s->mutex, NULL);
pthread_cond_init(&s->wakeup, NULL);
cache->priv = s;
s->cache = cache;
s->stream = stream;
cache->seek = cache_seek;
cache->fill_buffer = cache_fill_buffer;
cache->control = cache_control;
cache->close = cache_uninit;
int64_t min = opts->initial * 1024ULL;
if (min > s->buffer_size - FILL_LIMIT)
min = s->buffer_size - FILL_LIMIT;
s->seekable = stream->seekable;
if (pthread_create(&s->cache_thread, NULL, cache_thread, s) != 0) {
MP_ERR(s, "Starting cache thread failed.\n");
return -1;
}
s->cache_thread_running = true;
// wait until cache is filled with at least min bytes
if (min < 1)
return 1;
for (;;) {
if (mp_cancel_test(cache->cancel))
return -1;
int64_t fill;
int idle;
if (stream_control(s->cache, STREAM_CTRL_GET_CACHE_FILL, &fill) < 0)
break;
if (stream_control(s->cache, STREAM_CTRL_GET_CACHE_IDLE, &idle) < 0)
break;
MP_INFO(s, "\rCache fill: %5.2f%% "
"(%" PRId64 " bytes) ", 100.0 * fill / s->buffer_size, fill);
if (fill >= min)
break;
if (idle)
break; // file is smaller than prefill size
// Wake up if the cache is done reading some data (or on timeout/abort)
pthread_mutex_lock(&s->mutex);
s->control = CACHE_CTRL_PING;
pthread_cond_signal(&s->wakeup);
cache_wakeup_and_wait(s, &(double){0});
pthread_mutex_unlock(&s->mutex);
}
// Runs in the cache thread.
// Returns true if reading was attempted, and the mutex was shortly unlocked.
static bool cache_fill(struct priv *s)
{
int64_t read = s->read_filepos;
int len = 0;
// 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) {
MP_VERBOSE(s, "Dropping cache at pos %"PRId64", "
"cached range: %"PRId64"-%"PRId64".\n", read,
s->min_filepos, s->max_filepos);
cache_drop_contents(s);
}
if (stream_tell(s->stream) != s->max_filepos && s->seekable) {
MP_VERBOSE(s, "Seeking underlying stream: %"PRId64" -> %"PRId64"\n",
stream_tell(s->stream), s->max_filepos);
stream_seek(s->stream, s->max_filepos);
if (stream_tell(s->stream) != s->max_filepos)
goto done;
}
if (mp_cancel_test(s->cache->cancel))
goto done;
// number of buffer bytes which should be preserved in backwards direction
int64_t back = MPCLAMP(read - s->min_filepos, 0, s->back_size);
// limit maximum readahead so that the backbuffer space is reserved, even
// if the backbuffer is not used. limit it to ensure that we don't stall the
// network when starting a file, or we wouldn't download new data until we
// get new free space again. (unless everything fits in the cache.)
if (s->stream_size > s->buffer_size)
back = MPMAX(back, s->back_size);
// number of buffer bytes that are valid and can be read
int64_t newb = FFMAX(s->max_filepos - read, 0);
// max. number of bytes that can be written (starting from max_filepos)
int64_t space = s->buffer_size - (newb + back);
// offset into the buffer that maps to max_filepos
int64_t pos = s->max_filepos - s->offset;
if (pos >= s->buffer_size)
pos -= s->buffer_size; // wrap-around
if (space < FILL_LIMIT) {
s->idle = true;
s->reads++; // don't stuck main thread
return false;
}
// limit to end of buffer (without wrapping)
if (pos + space >= s->buffer_size)
space = s->buffer_size - pos;
// limit read size (or else would block and read the entire buffer in 1 call)
space = FFMIN(space, s->stream->read_chunk);
// back+newb+space <= buffer_size
int64_t back2 = s->buffer_size - (space + newb); // max back size
if (s->min_filepos < (read - back2))
s->min_filepos = read - back2;
// The read call might take a long time and block, so drop the lock.
pthread_mutex_unlock(&s->mutex);
len = stream_read_partial(s->stream, &s->buffer[pos], space);
pthread_mutex_lock(&s->mutex);
// Do this after reading a block, because at least libdvdnav updates the
// stream position only after actually reading something after a seek.
if (s->start_pts == MP_NOPTS_VALUE) {
double pts;
if (stream_control(s->stream, STREAM_CTRL_GET_CURRENT_TIME, &pts) > 0)
s->start_pts = pts;
}
s->max_filepos += len;
if (pos + len == s->buffer_size)
s->offset += s->buffer_size; // wrap...
done:
s->eof = len <= 0;
s->idle = s->eof;
s->reads++;
if (s->eof) {
s->eof_pos = stream_tell(s->stream);
MP_TRACE(s, "EOF reached.\n");
}
pthread_cond_signal(&s->wakeup);
return true;
}
// Runs in the cache thread.
// Returns true if reading was attempted, and the mutex was shortly unlocked.
static bool cache_fill(struct priv *s)
{
int64_t read = s->read_filepos;
int len;
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) {
mp_msg(MSGT_CACHE, MSGL_V, "Dropping cache at pos %"PRId64", "
"cached range: %"PRId64"-%"PRId64".\n", read,
s->min_filepos, s->max_filepos);
cache_drop_contents(s);
stream_seek(s->stream, read);
}
}
// number of buffer bytes which should be preserved in backwards direction
int64_t back = mp_clipi64(read - s->min_filepos, 0, s->back_size);
// number of buffer bytes that are valid and can be read
int64_t newb = FFMAX(s->max_filepos - read, 0);
// max. number of bytes that can be written (starting from max_filepos)
int64_t space = s->buffer_size - (newb + back);
// offset into the buffer that maps to max_filepos
int pos = s->max_filepos - s->offset;
if (pos >= s->buffer_size)
pos -= s->buffer_size; // wrap-around
if (space < s->fill_limit) {
s->idle = true;
return false;
}
// limit to end of buffer (without wrapping)
if (pos + space >= s->buffer_size)
space = s->buffer_size - pos;
// limit read size (or else would block and read the entire buffer in 1 call)
space = FFMIN(space, s->stream->read_chunk);
// back+newb+space <= buffer_size
int64_t back2 = s->buffer_size - (space + newb); // max back size
if (s->min_filepos < (read - back2))
s->min_filepos = read - back2;
// The read call might take a long time and block, so drop the lock.
pthread_mutex_unlock(&s->mutex);
len = stream_read_partial(s->stream, &s->buffer[pos], space);
pthread_mutex_lock(&s->mutex);
double pts;
if (stream_control(s->stream, STREAM_CTRL_GET_CURRENT_TIME, &pts) <= 0)
pts = MP_NOPTS_VALUE;
for (int64_t b_pos = pos; b_pos < pos + len + BYTE_META_CHUNK_SIZE;
b_pos += BYTE_META_CHUNK_SIZE)
{
s->bm[b_pos / BYTE_META_CHUNK_SIZE] = (struct byte_meta){.stream_pts = pts};
}
s->max_filepos += len;
if (pos + len == s->buffer_size)
s->offset += s->buffer_size; // wrap...
s->eof = len > 0 ? 0 : 1;
s->idle = s->eof;
pthread_cond_signal(&s->wakeup);
return true;
}