1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
|
/*
* 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),
};
|
