137 lines
3.4 KiB
C
137 lines
3.4 KiB
C
/*
|
|
* Input cache protocol.
|
|
* Copyright (c) 2011 Michael Niedermayer
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg 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
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*
|
|
* Based on file.c by Fabrice Bellard
|
|
*/
|
|
|
|
/**
|
|
* @TODO
|
|
* support non continuous caching
|
|
* support keeping files
|
|
* support filling with a background thread
|
|
*/
|
|
|
|
#include "libavutil/avassert.h"
|
|
#include "libavutil/avstring.h"
|
|
#include "libavutil/file.h"
|
|
#include "avformat.h"
|
|
#include <fcntl.h>
|
|
#if HAVE_SETMODE
|
|
#include <io.h>
|
|
#endif
|
|
#include <unistd.h>
|
|
#include <sys/stat.h>
|
|
#include <stdlib.h>
|
|
#include "os_support.h"
|
|
#include "url.h"
|
|
|
|
typedef struct Context {
|
|
int fd;
|
|
int64_t end;
|
|
int64_t pos;
|
|
URLContext *inner;
|
|
} Context;
|
|
|
|
static int cache_open(URLContext *h, const char *arg, int flags)
|
|
{
|
|
char *buffername;
|
|
Context *c= h->priv_data;
|
|
|
|
av_strstart(arg, "cache:", &arg);
|
|
|
|
c->fd = av_tempfile("ffcache", &buffername, 0, h);
|
|
if (c->fd < 0){
|
|
av_log(h, AV_LOG_ERROR, "Failed to create tempfile\n");
|
|
return c->fd;
|
|
}
|
|
|
|
unlink(buffername);
|
|
av_freep(&buffername);
|
|
|
|
return ffurl_open(&c->inner, arg, flags, &h->interrupt_callback, NULL);
|
|
}
|
|
|
|
static int cache_read(URLContext *h, unsigned char *buf, int size)
|
|
{
|
|
Context *c= h->priv_data;
|
|
int r;
|
|
|
|
if(c->pos<c->end){
|
|
r = read(c->fd, buf, FFMIN(size, c->end - c->pos));
|
|
if(r>0)
|
|
c->pos += r;
|
|
return (-1 == r)?AVERROR(errno):r;
|
|
}else{
|
|
r = ffurl_read(c->inner, buf, size);
|
|
if(r > 0){
|
|
int r2= write(c->fd, buf, r);
|
|
av_assert0(r2==r); // FIXME handle cache failure
|
|
c->pos += r;
|
|
c->end += r;
|
|
}
|
|
return r;
|
|
}
|
|
}
|
|
|
|
static int64_t cache_seek(URLContext *h, int64_t pos, int whence)
|
|
{
|
|
Context *c= h->priv_data;
|
|
|
|
if (whence == AVSEEK_SIZE) {
|
|
pos= ffurl_seek(c->inner, pos, whence);
|
|
if(pos <= 0){
|
|
pos= ffurl_seek(c->inner, -1, SEEK_END);
|
|
ffurl_seek(c->inner, c->end, SEEK_SET);
|
|
if(pos <= 0)
|
|
return c->end;
|
|
}
|
|
return pos;
|
|
}
|
|
|
|
pos= lseek(c->fd, pos, whence);
|
|
if(pos<0){
|
|
return pos;
|
|
}else if(pos <= c->end){
|
|
c->pos= pos;
|
|
return pos;
|
|
}else{
|
|
lseek(c->fd, c->pos, SEEK_SET);
|
|
return AVERROR(EPIPE);
|
|
}
|
|
}
|
|
|
|
static int cache_close(URLContext *h)
|
|
{
|
|
Context *c= h->priv_data;
|
|
close(c->fd);
|
|
ffurl_close(c->inner);
|
|
|
|
return 0;
|
|
}
|
|
|
|
URLProtocol ff_cache_protocol = {
|
|
.name = "cache",
|
|
.url_open = cache_open,
|
|
.url_read = cache_read,
|
|
.url_seek = cache_seek,
|
|
.url_close = cache_close,
|
|
.priv_data_size = sizeof(Context),
|
|
};
|