Alter sha1close() 3rd argument to request flush only
[git/git.git] / csum-file.c
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
13 static void sha1flush(struct sha1file *f, unsigned int count)
14 {
15 void *buf = f->buffer;
16
17 for (;;) {
18 int ret = xwrite(f->fd, buf, count);
19 if (ret > 0) {
20 buf = (char *) buf + ret;
21 count -= ret;
22 if (count)
23 continue;
24 return;
25 }
26 if (!ret)
27 die("sha1 file '%s' write error. Out of diskspace", f->name);
28 die("sha1 file '%s' write error (%s)", f->name, strerror(errno));
29 }
30 }
31
32 int sha1close(struct sha1file *f, unsigned char *result, int final)
33 {
34 unsigned offset = f->offset;
35 if (offset) {
36 SHA1_Update(&f->ctx, f->buffer, offset);
37 sha1flush(f, offset);
38 f->offset = 0;
39 }
40 if (!final)
41 return 0; /* only want to flush (no checksum write, no close) */
42 SHA1_Final(f->buffer, &f->ctx);
43 if (result)
44 hashcpy(result, f->buffer);
45 sha1flush(f, 20);
46 if (close(f->fd))
47 die("%s: sha1 file error on close (%s)", f->name, strerror(errno));
48 free(f);
49 return 0;
50 }
51
52 int sha1write(struct sha1file *f, void *buf, unsigned int count)
53 {
54 if (f->do_crc)
55 f->crc32 = crc32(f->crc32, buf, count);
56 while (count) {
57 unsigned offset = f->offset;
58 unsigned left = sizeof(f->buffer) - offset;
59 unsigned nr = count > left ? left : count;
60
61 memcpy(f->buffer + offset, buf, nr);
62 count -= nr;
63 offset += nr;
64 buf = (char *) buf + nr;
65 left -= nr;
66 if (!left) {
67 SHA1_Update(&f->ctx, f->buffer, offset);
68 sha1flush(f, offset);
69 offset = 0;
70 }
71 f->offset = offset;
72 }
73 return 0;
74 }
75
76 struct sha1file *sha1create(const char *fmt, ...)
77 {
78 struct sha1file *f;
79 unsigned len;
80 va_list arg;
81 int fd;
82
83 f = xmalloc(sizeof(*f));
84
85 va_start(arg, fmt);
86 len = vsnprintf(f->name, sizeof(f->name), fmt, arg);
87 va_end(arg);
88 if (len >= PATH_MAX)
89 die("you wascally wabbit, you");
90 f->namelen = len;
91
92 fd = open(f->name, O_CREAT | O_EXCL | O_WRONLY, 0666);
93 if (fd < 0)
94 die("unable to open %s (%s)", f->name, strerror(errno));
95 f->fd = fd;
96 f->error = 0;
97 f->offset = 0;
98 f->do_crc = 0;
99 SHA1_Init(&f->ctx);
100 return f;
101 }
102
103 struct sha1file *sha1fd(int fd, const char *name)
104 {
105 struct sha1file *f;
106 unsigned len;
107
108 f = xmalloc(sizeof(*f));
109
110 len = strlen(name);
111 if (len >= PATH_MAX)
112 die("you wascally wabbit, you");
113 f->namelen = len;
114 memcpy(f->name, name, len+1);
115
116 f->fd = fd;
117 f->error = 0;
118 f->offset = 0;
119 f->do_crc = 0;
120 SHA1_Init(&f->ctx);
121 return f;
122 }
123
124 int sha1write_compressed(struct sha1file *f, void *in, unsigned int size, int level)
125 {
126 z_stream stream;
127 unsigned long maxsize;
128 void *out;
129
130 memset(&stream, 0, sizeof(stream));
131 deflateInit(&stream, level);
132 maxsize = deflateBound(&stream, size);
133 out = xmalloc(maxsize);
134
135 /* Compress it */
136 stream.next_in = in;
137 stream.avail_in = size;
138
139 stream.next_out = out;
140 stream.avail_out = maxsize;
141
142 while (deflate(&stream, Z_FINISH) == Z_OK)
143 /* nothing */;
144 deflateEnd(&stream);
145
146 size = stream.total_out;
147 sha1write(f, out, size);
148 free(out);
149 return size;
150 }
151
152 void crc32_begin(struct sha1file *f)
153 {
154 f->crc32 = crc32(0, Z_NULL, 0);
155 f->do_crc = 1;
156 }
157
158 uint32_t crc32_end(struct sha1file *f)
159 {
160 f->do_crc = 0;
161 return f->crc32;
162 }