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
|
/* fopencookie.c -- implement GNU-style fopencookie() with BSD-style funopen()
*
* Todo: handle "a+" mode (probably by keeping read and write file pointers and
* calling seek() before calling read or write)
*
* Todo: Is this solution, calling readfn() which in turn calls
* sc->read() with some typecasts, better than ignoring the compiler
* warnings and calling sc->read directly?
*
* Created: 22 August 2011
* Author: Bert Bos <bert@w3.org>
*
* Copyright © 2011 World Wide Web Consortium
* See http://www.w3.org/Consortium/Legal/2002/copyright-software-20021231
*/
#include "config.h"
#if HAVE_LIBCURL /* We only need this if we're using libcurl */
#if !HAVE_FOPENCOOKIE /* We don't need this on GNU Linux */
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include "errexit.e"
#include "fopencookie.h"
typedef struct {
cookie_read_function_t *read;
cookie_write_function_t *write;
cookie_seek_function_t *seek;
cookie_close_function_t *close;
void *cookie;
} cookiewrapper;
/* readfn -- callback that in turn calls sc->read with proper typecasts */
static int readfn(void *sc, char *buf, int n)
{
cookiewrapper *c = (cookiewrapper*)sc;
return (int)(c->read(c->cookie, buf, (size_t)n));
}
/* writefn -- callback that in turn calls sc->write with proper typecasts */
static int writefn(void *sc, const char *buf, int n)
{
cookiewrapper *c = (cookiewrapper*)sc;
return (int)(c->write(c->cookie, buf, (size_t)n));
}
/* seekfn -- callback that in turn calls sc->seek with proper typecasts */
static fpos_t seekfn(void *sc, fpos_t offset, int whence)
{
cookiewrapper *c = (cookiewrapper*)sc;
return (fpos_t)(c->seek(c->cookie, (off64_t)offset, whence));
}
/* closefn -- callback that in turn calls sc->close and then frees memory */
static int closefn(void *sc)
{
cookiewrapper *c = (cookiewrapper*)sc;
int r = c->close ? c->close(c->cookie) : 0;
free(sc);
return r;
}
/* fopencookie -- open a stream defined by four callback functions */
FILE *fopencookie(void *cookie, const char *mode,
cookie_io_functions_t funcs)
{
cookiewrapper *s;
int mask; /* 1 = read, 2 = write, 4 = append */
FILE *f;
/* Check that the parameters make sense */
if (!mode) {errno = EINVAL; return NULL;}
if (mode[0] == 'r') mask = 1;
else if (mode[0] == 'w') mask = 2;
else if (mode[0] == 'a') mask = 4;
else {errno = EINVAL; return NULL;}
if (mode[1] == '+' || (mode[1] =='b' && mode[2] == '+')) mask |= 3;
if ((mask & 1) && !funcs.read) {errno = EINVAL; return NULL;}
if ((mask & 2) && !funcs.write) {errno = EINVAL; return NULL;}
if ((mask & 4) && !funcs.seek) {errno = EINVAL; return NULL;}
if (mask == 7) errexit("Bug: fopencookie() can't yet handle mode \"a+\"\n");
/* Open the "file" */
if (!(s = malloc(sizeof(*s)))) {errno = ENOMEM; return NULL;}
s->read = funcs.read;
s->write = funcs.write;
s->seek = funcs.seek;
s->close = funcs.close;
s->cookie = cookie;
f = funopen(s,
s->read ? readfn : NULL,
s->write ? writefn : NULL,
s->seek ? seekfn : NULL,
closefn);
if (!f) {free(s); return NULL;}
/* If the mode is "a" (append), position the file pointer at the end */
if ((mask & 4) && fseek(f, 0L, SEEK_END) < 0) {fclose(f); return NULL;}
return f;
}
#endif /* !HAVE_FOPENCOOKIE */
#endif /* HAVE_LIBCURL */
|
