git-pull: do not barf on -a flag meant for git-fetch.
[git/git.git] / sha1_name.c
CommitLineData
9938af6a
JH
1#include "cache.h"
2#include "commit.h"
3
4static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
5{
99a19b43 6 struct alternate_object_database *alt;
9938af6a 7 char hex[40];
99a19b43
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8 int found = 0;
9 static struct alternate_object_database *fakeent;
10
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] = '/';
19 }
20 fakeent->next = alt_odb_list;
9938af6a 21
9938af6a 22 sprintf(hex, "%.2s", name);
99a19b43 23 for (alt = fakeent; alt && found < 2; alt = alt->next) {
9938af6a 24 struct dirent *de;
99a19b43
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25 DIR *dir;
26 sprintf(alt->name, "%.2s/", name);
27 dir = opendir(alt->base);
28 if (!dir)
29 continue;
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30 while ((de = readdir(dir)) != NULL) {
31 if (strlen(de->d_name) != 38)
32 continue;
99a19b43 33 if (memcmp(de->d_name, name + 2, len - 2))
9938af6a 34 continue;
99a19b43
JH
35 if (!found) {
36 memcpy(hex + 2, de->d_name, 38);
37 found++;
38 }
39 else if (memcmp(hex + 2, de->d_name, 38)) {
40 found = 2;
9938af6a 41 break;
99a19b43 42 }
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43 }
44 closedir(dir);
45 }
46 if (found == 1)
47 return get_sha1_hex(hex, sha1) == 0;
99a19b43 48 return found;
9938af6a
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49}
50
51static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
52{
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;
64}
65
66static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
67{
68 struct packed_git *p;
99a19b43
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69 unsigned char found_sha1[20];
70 int found = 0;
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71
72 prepare_packed_git();
99a19b43 73 for (p = packed_git; p && found < 2; p = p->next) {
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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;
80
81 nth_packed_object_sha1(p, mid, now);
82 cmp = memcmp(match, now, 20);
83 if (!cmp) {
84 first = mid;
85 break;
86 }
87 if (cmp > 0) {
88 first = mid+1;
89 continue;
90 }
91 last = mid;
92 }
93 if (first < num) {
99a19b43 94 unsigned char now[20];
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95 nth_packed_object_sha1(p, first, now);
96 if (match_sha(len, match, now)) {
99a19b43
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97 if (!found) {
98 memcpy(found_sha1, now, 20);
99 found++;
100 }
101 else if (memcmp(found_sha1, now, 20)) {
102 found = 2;
103 break;
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104 }
105 }
106 }
107 }
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108 if (found == 1)
109 memcpy(sha1, found_sha1, 20);
110 return found;
111}
112
113static int find_unique_short_object(int len, char *canonical,
114 unsigned char *res, unsigned char *sha1)
115{
116 int has_unpacked, has_packed;
117 unsigned char unpacked_sha1[20], packed_sha1[20];
118
119 has_unpacked = find_short_object_filename(len, canonical, unpacked_sha1);
120 has_packed = find_short_packed_object(len, res, packed_sha1);
121 if (!has_unpacked && !has_packed)
122 return -1;
123 if (1 < has_unpacked || 1 < has_packed)
124 return -1;
125 if (has_unpacked != has_packed) {
126 memcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1), 20);
127 return 0;
128 }
129 /* Both have unique ones -- do they match? */
130 if (memcmp(packed_sha1, unpacked_sha1, 20))
5a82b4fb 131 return error("short SHA1 %.*s is ambiguous.", len, canonical);
99a19b43 132 memcpy(sha1, packed_sha1, 20);
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133 return 0;
134}
135
af61c6e0 136static int get_short_sha1(const char *name, int len, unsigned char *sha1)
9938af6a
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137{
138 int i;
139 char canonical[40];
140 unsigned char res[20];
141
af61c6e0
LT
142 if (len < 4)
143 return -1;
9938af6a
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144 memset(res, 0, 20);
145 memset(canonical, 'x', 40);
af61c6e0 146 for (i = 0; i < len ;i++) {
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147 unsigned char c = name[i];
148 unsigned char val;
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149 if (c >= '0' && c <= '9')
150 val = c - '0';
151 else if (c >= 'a' && c <= 'f')
152 val = c - 'a' + 10;
153 else if (c >= 'A' && c <='F') {
154 val = c - 'A' + 10;
155 c -= 'A' - 'a';
156 }
157 else
158 return -1;
159 canonical[i] = c;
160 if (!(i & 1))
161 val <<= 4;
162 res[i >> 1] |= val;
163 }
99a19b43
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164
165 return find_unique_short_object(i, canonical, res, sha1);
9938af6a
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166}
167
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168static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
169{
170 static const char *prefix[] = {
171 "",
172 "refs",
173 "refs/tags",
174 "refs/heads",
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175 NULL
176 };
177 const char **p;
178
3c3852e3 179 if (len == 40 && !get_sha1_hex(str, sha1))
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180 return 0;
181
182 for (p = prefix; *p; p++) {
183 char *pathname = git_path("%s/%.*s", *p, len, str);
ca8db142 184 if (!read_ref(pathname, sha1))
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185 return 0;
186 }
187
188 return -1;
189}
190
191static int get_sha1_1(const char *name, int len, unsigned char *sha1);
192
193static int get_parent(const char *name, int len,
194 unsigned char *result, int idx)
195{
196 unsigned char sha1[20];
197 int ret = get_sha1_1(name, len, sha1);
198 struct commit *commit;
199 struct commit_list *p;
200
201 if (ret)
202 return ret;
203 commit = lookup_commit_reference(sha1);
204 if (!commit)
205 return -1;
206 if (parse_commit(commit))
207 return -1;
208 if (!idx) {
209 memcpy(result, commit->object.sha1, 20);
210 return 0;
211 }
212 p = commit->parents;
213 while (p) {
214 if (!--idx) {
215 memcpy(result, p->item->object.sha1, 20);
216 return 0;
217 }
218 p = p->next;
219 }
220 return -1;
221}
222
4f7599ac
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223static int get_nth_ancestor(const char *name, int len,
224 unsigned char *result, int generation)
225{
226 unsigned char sha1[20];
227 int ret = get_sha1_1(name, len, sha1);
228 if (ret)
229 return ret;
230
231 while (generation--) {
232 struct commit *commit = lookup_commit_reference(sha1);
233
234 if (!commit || parse_commit(commit) || !commit->parents)
235 return -1;
236 memcpy(sha1, commit->parents->item->object.sha1, 20);
237 }
238 memcpy(result, sha1, 20);
239 return 0;
240}
241
9938af6a
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242static int get_sha1_1(const char *name, int len, unsigned char *sha1)
243{
244 int parent, ret;
4f7599ac 245 const char *cp;
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246
247 /* foo^[0-9] or foo^ (== foo^1); we do not do more than 9 parents. */
248 if (len > 2 && name[len-2] == '^' &&
249 name[len-1] >= '0' && name[len-1] <= '9') {
250 parent = name[len-1] - '0';
251 len -= 2;
252 }
ef0bd2e6 253 else if (len > 1 && name[len-1] == '^') {
9938af6a 254 parent = 1;
ef0bd2e6
JS
255 len--;
256 } else
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257 parent = -1;
258
02a4a32c
LT
259 if (parent >= 0)
260 return get_parent(name, len, sha1, parent);
261
4f7599ac
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262 /* "name~3" is "name^^^",
263 * "name~12" is "name^^^^^^^^^^^^", and
264 * "name~" and "name~0" are name -- not "name^0"!
265 */
266 parent = 0;
267 for (cp = name + len - 1; name <= cp; cp--) {
268 int ch = *cp;
269 if ('0' <= ch && ch <= '9')
270 continue;
271 if (ch != '~')
272 parent = -1;
273 break;
274 }
275 if (!parent && *cp == '~') {
276 int len1 = cp - name;
277 cp++;
278 while (cp < name + len)
279 parent = parent * 10 + *cp++ - '0';
280 return get_nth_ancestor(name, len1, sha1, parent);
281 }
282
9938af6a
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283 ret = get_sha1_basic(name, len, sha1);
284 if (!ret)
285 return 0;
af61c6e0 286 return get_short_sha1(name, len, sha1);
9938af6a
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287}
288
289/*
290 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
291 * notably "xyz^" for "parent of xyz"
292 */
293int get_sha1(const char *name, unsigned char *sha1)
294{
99a19b43 295 prepare_alt_odb();
9938af6a
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296 return get_sha1_1(name, strlen(name), sha1);
297}