1
0
mirror of https://github.com/mpv-player/mpv synced 2024-12-24 15:52:25 +00:00
mpv/stream/cache_file.c
wm4 c80adac077 cache_file: add a mode that creates a temporary file
Since we have to be portable, our options for creating temporary files
are somewhat limited. tmpfile() happens to be available everywhere, so
use that. This function doesn't allow having a "visible" filename or
location, so we use the magic string "TMP" for this.
2014-08-30 20:03:31 +02:00

154 lines
4.5 KiB
C

/*
* This file is part of mpv.
*
* mpv 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.
*
* mpv 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 mpv. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdio.h>
#include <stdint.h>
#include "osdep/io.h"
#include "common/common.h"
#include "common/msg.h"
#include "options/options.h"
#include "stream.h"
#define BLOCK_SIZE 1024LL
#define BLOCK_ALIGN(p) ((p) & ~(BLOCK_SIZE - 1))
struct priv {
struct stream *original;
FILE *cache_file;
uint8_t *block_bits; // 1 bit for each BLOCK_SIZE, whether block was read
int64_t size; // currently known size
int64_t max_size; // max. size for block_bits and cache_file
};
static bool test_bit(struct priv *p, int64_t pos)
{
if (pos < 0 || pos >= p->size)
return false;
size_t block = pos / BLOCK_SIZE;
return p->block_bits[block / 8] & (1 << (block % 8));
}
static void set_bit(struct priv *p, int64_t pos, bool bit)
{
if (pos < 0 || pos >= p->size)
return;
size_t block = pos / BLOCK_SIZE;
unsigned int m = (1 << (block % 8));
p->block_bits[block / 8] = (p->block_bits[block / 8] & ~m) | (bit ? m : 0);
}
static int fill_buffer(stream_t *s, char *buffer, int max_len)
{
struct priv *p = s->priv;
if (s->pos < 0)
return -1;
if (s->pos >= p->max_size) {
if (stream_seek(p->original, s->pos) < 1)
return -1;
return stream_read(p->original, buffer, max_len);
}
// Size of file changes -> invalidate last block
if (s->pos >= p->size - BLOCK_SIZE) {
int64_t new_size = -1;
stream_control(s, STREAM_CTRL_GET_SIZE, &new_size);
if (p->size >= 0 && new_size != p->size)
set_bit(p, BLOCK_ALIGN(p->size), 0);
p->size = MPMIN(p->max_size, new_size);
}
int64_t aligned = BLOCK_ALIGN(s->pos);
if (!test_bit(p, aligned)) {
char tmp[BLOCK_SIZE];
stream_seek(p->original, aligned);
int r = stream_read(p->original, tmp, BLOCK_SIZE);
if (r < BLOCK_SIZE) {
if (p->size < 0) {
MP_WARN(s, "suspected EOF\n");
} else if (aligned + r < p->size) {
MP_ERR(s, "unexpected EOF\n");
return -1;
}
}
if (fseeko(p->cache_file, aligned, SEEK_SET))
return -1;
if (fwrite(tmp, r, 1, p->cache_file) != 1)
return -1;
set_bit(p, aligned, 1);
}
if (fseeko(p->cache_file, s->pos, SEEK_SET))
return -1;
// align/limit to blocks
max_len = MPMIN(max_len, BLOCK_SIZE - (s->pos % BLOCK_SIZE));
// Limit to max. known file size
if (p->size >= 0)
max_len = MPMIN(max_len, p->size - s->pos);
return fread(buffer, 1, max_len, p->cache_file);
}
static int seek(stream_t *s, int64_t newpos)
{
return 1;
}
static int control(stream_t *s, int cmd, void *arg)
{
struct priv *p = s->priv;
return stream_control(p->original, cmd, arg);
}
static void s_close(stream_t *s)
{
struct priv *p = s->priv;
if (p->cache_file)
fclose(p->cache_file);
talloc_free(p);
}
// return 1 on success, 0 if disabled, -1 on error
int stream_file_cache_init(stream_t *cache, stream_t *stream,
struct mp_cache_opts *opts)
{
if (!opts->file || !opts->file[0] || opts->file_max < 1)
return 0;
bool use_anon_file = strcmp(opts->file, "TMP") == 0;
FILE *file = use_anon_file ? tmpfile() : fopen(opts->file, "wb+");
if (!file) {
MP_ERR(cache, "can't open cache file '%s'\n", opts->file);
return -1;
}
struct priv *p = talloc_zero(NULL, struct priv);
cache->priv = p;
p->original = stream;
p->cache_file = file;
p->max_size = opts->file_max * 1024LL;
// file_max can be INT_MAX, so this is at most about 256MB
p->block_bits = talloc_zero_size(p, (p->max_size / BLOCK_SIZE + 1) / 8 + 1);
cache->seek = seek;
cache->fill_buffer = fill_buffer;
cache->control = control;
cache->close = s_close;
return 1;
}