| /* |
| * 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_IO_H |
| #include <io.h> |
| #endif |
| #if HAVE_UNISTD_H |
| #include <unistd.h> |
| #endif |
| #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{ |
| if(lseek(c->fd, c->pos, SEEK_SET) < 0) { |
| av_log(h, AV_LOG_ERROR, "Failure to seek in cache\n"); |
| } |
| 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), |
| }; |