Initial revision of "git", the information manager from hell
[git/git.git] / read-cache.c
CommitLineData
e83c5163
LT
1#include "cache.h"
2
3const char *sha1_file_directory = NULL;
4struct cache_entry **active_cache = NULL;
5unsigned int active_nr = 0, active_alloc = 0;
6
7void usage(const char *err)
8{
9 fprintf(stderr, "read-tree: %s\n", err);
10 exit(1);
11}
12
13static unsigned hexval(char c)
14{
15 if (c >= '0' && c <= '9')
16 return c - '0';
17 if (c >= 'a' && c <= 'f')
18 return c - 'a' + 10;
19 if (c >= 'A' && c <= 'F')
20 return c - 'A' + 10;
21 return ~0;
22}
23
24int get_sha1_hex(char *hex, unsigned char *sha1)
25{
26 int i;
27 for (i = 0; i < 20; i++) {
28 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
29 if (val & ~0xff)
30 return -1;
31 *sha1++ = val;
32 hex += 2;
33 }
34 return 0;
35}
36
37char * sha1_to_hex(unsigned char *sha1)
38{
39 static char buffer[50];
40 static const char hex[] = "0123456789abcdef";
41 char *buf = buffer;
42 int i;
43
44 for (i = 0; i < 20; i++) {
45 unsigned int val = *sha1++;
46 *buf++ = hex[val >> 4];
47 *buf++ = hex[val & 0xf];
48 }
49 return buffer;
50}
51
52/*
53 * NOTE! This returns a statically allocated buffer, so you have to be
54 * careful about using it. Do a "strdup()" if you need to save the
55 * filename.
56 */
57char *sha1_file_name(unsigned char *sha1)
58{
59 int i;
60 static char *name, *base;
61
62 if (!base) {
63 char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
64 int len = strlen(sha1_file_directory);
65 base = malloc(len + 60);
66 memcpy(base, sha1_file_directory, len);
67 memset(base+len, 0, 60);
68 base[len] = '/';
69 base[len+3] = '/';
70 name = base + len + 1;
71 }
72 for (i = 0; i < 20; i++) {
73 static char hex[] = "0123456789abcdef";
74 unsigned int val = sha1[i];
75 char *pos = name + i*2 + (i > 0);
76 *pos++ = hex[val >> 4];
77 *pos = hex[val & 0xf];
78 }
79 return base;
80}
81
82void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size)
83{
84 z_stream stream;
85 char buffer[8192];
86 struct stat st;
87 int i, fd, ret, bytes;
88 void *map, *buf;
89 char *filename = sha1_file_name(sha1);
90
91 fd = open(filename, O_RDONLY);
92 if (fd < 0) {
93 perror(filename);
94 return NULL;
95 }
96 if (fstat(fd, &st) < 0) {
97 close(fd);
98 return NULL;
99 }
100 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
101 close(fd);
102 if (-1 == (int)(long)map)
103 return NULL;
104
105 /* Get the data stream */
106 memset(&stream, 0, sizeof(stream));
107 stream.next_in = map;
108 stream.avail_in = st.st_size;
109 stream.next_out = buffer;
110 stream.avail_out = sizeof(buffer);
111
112 inflateInit(&stream);
113 ret = inflate(&stream, 0);
114 if (sscanf(buffer, "%10s %lu", type, size) != 2)
115 return NULL;
116 bytes = strlen(buffer) + 1;
117 buf = malloc(*size);
118 if (!buf)
119 return NULL;
120
121 memcpy(buf, buffer + bytes, stream.total_out - bytes);
122 bytes = stream.total_out - bytes;
123 if (bytes < *size && ret == Z_OK) {
124 stream.next_out = buf + bytes;
125 stream.avail_out = *size - bytes;
126 while (inflate(&stream, Z_FINISH) == Z_OK)
127 /* nothing */;
128 }
129 inflateEnd(&stream);
130 return buf;
131}
132
133int write_sha1_file(char *buf, unsigned len)
134{
135 int size;
136 char *compressed;
137 z_stream stream;
138 unsigned char sha1[20];
139 SHA_CTX c;
140
141 /* Set it up */
142 memset(&stream, 0, sizeof(stream));
143 deflateInit(&stream, Z_BEST_COMPRESSION);
144 size = deflateBound(&stream, len);
145 compressed = malloc(size);
146
147 /* Compress it */
148 stream.next_in = buf;
149 stream.avail_in = len;
150 stream.next_out = compressed;
151 stream.avail_out = size;
152 while (deflate(&stream, Z_FINISH) == Z_OK)
153 /* nothing */;
154 deflateEnd(&stream);
155 size = stream.total_out;
156
157 /* Sha1.. */
158 SHA1_Init(&c);
159 SHA1_Update(&c, compressed, size);
160 SHA1_Final(sha1, &c);
161
162 if (write_sha1_buffer(sha1, compressed, size) < 0)
163 return -1;
164 printf("%s\n", sha1_to_hex(sha1));
165 return 0;
166}
167
168int write_sha1_buffer(unsigned char *sha1, void *buf, unsigned int size)
169{
170 char *filename = sha1_file_name(sha1);
171 int i, fd;
172
173 fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
174 if (fd < 0)
175 return (errno == EEXIST) ? 0 : -1;
176 write(fd, buf, size);
177 close(fd);
178 return 0;
179}
180
181static int error(const char * string)
182{
183 fprintf(stderr, "error: %s\n", string);
184 return -1;
185}
186
187static int verify_hdr(struct cache_header *hdr, unsigned long size)
188{
189 SHA_CTX c;
190 unsigned char sha1[20];
191
192 if (hdr->signature != CACHE_SIGNATURE)
193 return error("bad signature");
194 if (hdr->version != 1)
195 return error("bad version");
196 SHA1_Init(&c);
197 SHA1_Update(&c, hdr, offsetof(struct cache_header, sha1));
198 SHA1_Update(&c, hdr+1, size - sizeof(*hdr));
199 SHA1_Final(sha1, &c);
200 if (memcmp(sha1, hdr->sha1, 20))
201 return error("bad header sha1");
202 return 0;
203}
204
205int read_cache(void)
206{
207 int fd, i;
208 struct stat st;
209 unsigned long size, offset;
210 void *map;
211 struct cache_header *hdr;
212
213 errno = EBUSY;
214 if (active_cache)
215 return error("more than one cachefile");
216 errno = ENOENT;
217 sha1_file_directory = getenv(DB_ENVIRONMENT);
218 if (!sha1_file_directory)
219 sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
220 if (access(sha1_file_directory, X_OK) < 0)
221 return error("no access to SHA1 file directory");
222 fd = open(".dircache/index", O_RDONLY);
223 if (fd < 0)
224 return (errno == ENOENT) ? 0 : error("open failed");
225
226 map = (void *)-1;
227 if (!fstat(fd, &st)) {
228 map = NULL;
229 size = st.st_size;
230 errno = EINVAL;
231 if (size > sizeof(struct cache_header))
232 map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
233 }
234 close(fd);
235 if (-1 == (int)(long)map)
236 return error("mmap failed");
237
238 hdr = map;
239 if (verify_hdr(hdr, size) < 0)
240 goto unmap;
241
242 active_nr = hdr->entries;
243 active_alloc = alloc_nr(active_nr);
244 active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
245
246 offset = sizeof(*hdr);
247 for (i = 0; i < hdr->entries; i++) {
248 struct cache_entry *ce = map + offset;
249 offset = offset + ce_size(ce);
250 active_cache[i] = ce;
251 }
252 return active_nr;
253
254unmap:
255 munmap(map, size);
256 errno = EINVAL;
257 return error("verify header failed");
258}
259