git-pack-objects: write the pack files with a SHA1 csum
[git/git.git] / csum-file.c
CommitLineData
c38138cd
LT
1/*
2 * csum-file.c
3 *
4 * Copyright (C) 2005 Linus Torvalds
5 *
6 * Simple file write infrastructure for writing SHA1-summed
7 * files. Useful when you write a file that you want to be
8 * able to verify hasn't been messed with afterwards.
9 */
10#include "cache.h"
11#include "csum-file.h"
12
13static int sha1flush(struct sha1file *f, unsigned int count)
14{
15 void *buf = f->buffer;
16
17 for (;;) {
18 int ret = write(f->fd, buf, count);
19 if (ret > 0) {
20 buf += ret;
21 count -= ret;
22 if (count)
23 continue;
24 return 0;
25 }
26 if (!ret)
27 die("sha1 file write error. Out of diskspace");
28 if (errno == EAGAIN || errno == EINTR)
29 continue;
30 die("sha1 file write error (%s)", strerror(errno));
31 }
32}
33
34int sha1close(struct sha1file *f)
35{
36 unsigned offset = f->offset;
37 if (offset) {
38 SHA1_Update(&f->ctx, f->buffer, offset);
39 sha1flush(f, offset);
40 }
41 SHA1_Final(f->buffer, &f->ctx);
42 sha1flush(f, 20);
43 return 0;
44}
45
46int sha1write(struct sha1file *f, void *buf, unsigned int count)
47{
48 while (count) {
49 unsigned offset = f->offset;
50 unsigned left = sizeof(f->buffer) - offset;
51 unsigned nr = count > left ? left : count;
52
53 memcpy(f->buffer + offset, buf, nr);
54 count -= nr;
55 offset += nr;
56 left -= nr;
57 if (!left) {
58 SHA1_Update(&f->ctx, f->buffer, offset);
59 sha1flush(f, offset);
60 offset = 0;
61 }
62 f->offset = offset;
63 }
64 return 0;
65}
66
67struct sha1file *sha1create(const char *fmt, ...)
68{
69 static char filename[PATH_MAX];
70 struct sha1file *f;
71 unsigned len;
72 va_list arg;
73 int fd;
74
75 va_start(arg, fmt);
76 len = vsnprintf(filename, PATH_MAX, fmt, arg);
77 va_end(arg);
78
79 if (len >= PATH_MAX)
80 die("you wascally wabbit, you");
81 fd = open(filename, O_CREAT | O_EXCL | O_WRONLY, 0644);
82 if (fd < 0)
83 die("unable to open %s (%s)", filename, strerror(errno));
84 f = xmalloc(sizeof(*f));
85 f->fd = fd;
86 f->error = 0;
87 f->offset = 0;
88 SHA1_Init(&f->ctx);
89 return f;
90}
91
92int sha1write_compressed(struct sha1file *f, void *in, unsigned int size)
93{
94 z_stream stream;
95 unsigned long maxsize;
96 void *out;
97
98 memset(&stream, 0, sizeof(stream));
99 deflateInit(&stream, Z_DEFAULT_COMPRESSION);
100 maxsize = deflateBound(&stream, size);
101 out = xmalloc(maxsize);
102
103 /* Compress it */
104 stream.next_in = in;
105 stream.avail_in = size;
106
107 stream.next_out = out;
108 stream.avail_out = maxsize;
109
110 while (deflate(&stream, Z_FINISH) == Z_OK)
111 /* nothing */;
112 deflateEnd(&stream);
113
114 size = stream.total_out;
115 sha1write(f, out, size);
116 free(out);
117 return size;
118}
119
120