The synopsis of the manpages should use the hyphenated version
[git/dscho.git] / sha1_name.c
blobf64755fbceea617c424b9b83999eeaa91bf76af1
1 #include "cache.h"
2 #include "commit.h"
4 static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
6 struct alternate_object_database *alt;
7 char hex[40];
8 int found = 0;
9 static struct alternate_object_database *fakeent;
11 if (!fakeent) {
12 const char *objdir = get_object_directory();
13 int objdir_len = strlen(objdir);
14 int entlen = objdir_len + 43;
15 fakeent = xmalloc(sizeof(*fakeent) + entlen);
16 memcpy(fakeent->base, objdir, objdir_len);
17 fakeent->name = fakeent->base + objdir_len + 1;
18 fakeent->name[-1] = '/';
20 fakeent->next = alt_odb_list;
22 sprintf(hex, "%.2s", name);
23 for (alt = fakeent; alt && found < 2; alt = alt->next) {
24 struct dirent *de;
25 DIR *dir;
26 sprintf(alt->name, "%.2s/", name);
27 dir = opendir(alt->base);
28 if (!dir)
29 continue;
30 while ((de = readdir(dir)) != NULL) {
31 if (strlen(de->d_name) != 38)
32 continue;
33 if (memcmp(de->d_name, name + 2, len - 2))
34 continue;
35 if (!found) {
36 memcpy(hex + 2, de->d_name, 38);
37 found++;
39 else if (memcmp(hex + 2, de->d_name, 38)) {
40 found = 2;
41 break;
44 closedir(dir);
46 if (found == 1)
47 return get_sha1_hex(hex, sha1) == 0;
48 return found;
51 static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
53 do {
54 if (*a != *b)
55 return 0;
56 a++;
57 b++;
58 len -= 2;
59 } while (len > 1);
60 if (len)
61 if ((*a ^ *b) & 0xf0)
62 return 0;
63 return 1;
66 static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
68 struct packed_git *p;
69 unsigned char found_sha1[20];
70 int found = 0;
72 prepare_packed_git();
73 for (p = packed_git; p && found < 2; p = p->next) {
74 unsigned num = num_packed_objects(p);
75 unsigned first = 0, last = num;
76 while (first < last) {
77 unsigned mid = (first + last) / 2;
78 unsigned char now[20];
79 int cmp;
81 nth_packed_object_sha1(p, mid, now);
82 cmp = memcmp(match, now, 20);
83 if (!cmp) {
84 first = mid;
85 break;
87 if (cmp > 0) {
88 first = mid+1;
89 continue;
91 last = mid;
93 if (first < num) {
94 unsigned char now[20], next[20];
95 nth_packed_object_sha1(p, first, now);
96 if (match_sha(len, match, now)) {
97 if (nth_packed_object_sha1(p, first+1, next) ||
98 !match_sha(len, match, next)) {
99 /* unique within this pack */
100 if (!found) {
101 memcpy(found_sha1, now, 20);
102 found++;
104 else if (memcmp(found_sha1, now, 20)) {
105 found = 2;
106 break;
109 else {
110 /* not even unique within this pack */
111 found = 2;
112 break;
117 if (found == 1)
118 memcpy(sha1, found_sha1, 20);
119 return found;
122 static int find_unique_short_object(int len, char *canonical,
123 unsigned char *res, unsigned char *sha1)
125 int has_unpacked, has_packed;
126 unsigned char unpacked_sha1[20], packed_sha1[20];
128 has_unpacked = find_short_object_filename(len, canonical, unpacked_sha1);
129 has_packed = find_short_packed_object(len, res, packed_sha1);
130 if (!has_unpacked && !has_packed)
131 return -1;
132 if (1 < has_unpacked || 1 < has_packed)
133 return error("short SHA1 %.*s is ambiguous.", len, canonical);
134 if (has_unpacked != has_packed) {
135 memcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1), 20);
136 return 0;
138 /* Both have unique ones -- do they match? */
139 if (memcmp(packed_sha1, unpacked_sha1, 20))
140 return error("short SHA1 %.*s is ambiguous.", len, canonical);
141 memcpy(sha1, packed_sha1, 20);
142 return 0;
145 static int get_short_sha1(const char *name, int len, unsigned char *sha1)
147 int i;
148 char canonical[40];
149 unsigned char res[20];
151 if (len < 4)
152 return -1;
153 memset(res, 0, 20);
154 memset(canonical, 'x', 40);
155 for (i = 0; i < len ;i++) {
156 unsigned char c = name[i];
157 unsigned char val;
158 if (c >= '0' && c <= '9')
159 val = c - '0';
160 else if (c >= 'a' && c <= 'f')
161 val = c - 'a' + 10;
162 else if (c >= 'A' && c <='F') {
163 val = c - 'A' + 10;
164 c -= 'A' - 'a';
166 else
167 return -1;
168 canonical[i] = c;
169 if (!(i & 1))
170 val <<= 4;
171 res[i >> 1] |= val;
174 return find_unique_short_object(i, canonical, res, sha1);
177 static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
179 static const char *prefix[] = {
181 "refs",
182 "refs/tags",
183 "refs/heads",
184 NULL
186 const char **p;
188 if (len == 40 && !get_sha1_hex(str, sha1))
189 return 0;
191 for (p = prefix; *p; p++) {
192 char *pathname = git_path("%s/%.*s", *p, len, str);
193 if (!read_ref(pathname, sha1))
194 return 0;
197 return -1;
200 static int get_sha1_1(const char *name, int len, unsigned char *sha1);
202 static int get_parent(const char *name, int len,
203 unsigned char *result, int idx)
205 unsigned char sha1[20];
206 int ret = get_sha1_1(name, len, sha1);
207 struct commit *commit;
208 struct commit_list *p;
210 if (ret)
211 return ret;
212 commit = lookup_commit_reference(sha1);
213 if (!commit)
214 return -1;
215 if (parse_commit(commit))
216 return -1;
217 if (!idx) {
218 memcpy(result, commit->object.sha1, 20);
219 return 0;
221 p = commit->parents;
222 while (p) {
223 if (!--idx) {
224 memcpy(result, p->item->object.sha1, 20);
225 return 0;
227 p = p->next;
229 return -1;
232 static int get_nth_ancestor(const char *name, int len,
233 unsigned char *result, int generation)
235 unsigned char sha1[20];
236 int ret = get_sha1_1(name, len, sha1);
237 if (ret)
238 return ret;
240 while (generation--) {
241 struct commit *commit = lookup_commit_reference(sha1);
243 if (!commit || parse_commit(commit) || !commit->parents)
244 return -1;
245 memcpy(sha1, commit->parents->item->object.sha1, 20);
247 memcpy(result, sha1, 20);
248 return 0;
251 static int get_sha1_1(const char *name, int len, unsigned char *sha1)
253 int parent, ret;
254 const char *cp;
256 /* foo^[0-9] or foo^ (== foo^1); we do not do more than 9 parents. */
257 if (len > 2 && name[len-2] == '^' &&
258 name[len-1] >= '0' && name[len-1] <= '9') {
259 parent = name[len-1] - '0';
260 len -= 2;
262 else if (len > 1 && name[len-1] == '^') {
263 parent = 1;
264 len--;
265 } else
266 parent = -1;
268 if (parent >= 0)
269 return get_parent(name, len, sha1, parent);
271 /* "name~3" is "name^^^",
272 * "name~12" is "name^^^^^^^^^^^^", and
273 * "name~" and "name~0" are name -- not "name^0"!
275 parent = 0;
276 for (cp = name + len - 1; name <= cp; cp--) {
277 int ch = *cp;
278 if ('0' <= ch && ch <= '9')
279 continue;
280 if (ch != '~')
281 parent = -1;
282 break;
284 if (!parent && *cp == '~') {
285 int len1 = cp - name;
286 cp++;
287 while (cp < name + len)
288 parent = parent * 10 + *cp++ - '0';
289 return get_nth_ancestor(name, len1, sha1, parent);
292 ret = get_sha1_basic(name, len, sha1);
293 if (!ret)
294 return 0;
295 return get_short_sha1(name, len, sha1);
299 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
300 * notably "xyz^" for "parent of xyz"
302 int get_sha1(const char *name, unsigned char *sha1)
304 prepare_alt_odb();
305 return get_sha1_1(name, strlen(name), sha1);