Merge branch 'jc/for-each-ref' into jc/ref-locking
[git/git.git] / sha1_name.c
1 #include "cache.h"
2 #include "tag.h"
3 #include "commit.h"
4 #include "tree.h"
5 #include "blob.h"
6 #include "tree-walk.h"
7 #include "refs.h"
8
9 static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
10 {
11 struct alternate_object_database *alt;
12 char hex[40];
13 int found = 0;
14 static struct alternate_object_database *fakeent;
15
16 if (!fakeent) {
17 const char *objdir = get_object_directory();
18 int objdir_len = strlen(objdir);
19 int entlen = objdir_len + 43;
20 fakeent = xmalloc(sizeof(*fakeent) + entlen);
21 memcpy(fakeent->base, objdir, objdir_len);
22 fakeent->name = fakeent->base + objdir_len + 1;
23 fakeent->name[-1] = '/';
24 }
25 fakeent->next = alt_odb_list;
26
27 sprintf(hex, "%.2s", name);
28 for (alt = fakeent; alt && found < 2; alt = alt->next) {
29 struct dirent *de;
30 DIR *dir;
31 sprintf(alt->name, "%.2s/", name);
32 dir = opendir(alt->base);
33 if (!dir)
34 continue;
35 while ((de = readdir(dir)) != NULL) {
36 if (strlen(de->d_name) != 38)
37 continue;
38 if (memcmp(de->d_name, name + 2, len - 2))
39 continue;
40 if (!found) {
41 memcpy(hex + 2, de->d_name, 38);
42 found++;
43 }
44 else if (memcmp(hex + 2, de->d_name, 38)) {
45 found = 2;
46 break;
47 }
48 }
49 closedir(dir);
50 }
51 if (found == 1)
52 return get_sha1_hex(hex, sha1) == 0;
53 return found;
54 }
55
56 static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
57 {
58 do {
59 if (*a != *b)
60 return 0;
61 a++;
62 b++;
63 len -= 2;
64 } while (len > 1);
65 if (len)
66 if ((*a ^ *b) & 0xf0)
67 return 0;
68 return 1;
69 }
70
71 static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
72 {
73 struct packed_git *p;
74 unsigned char found_sha1[20];
75 int found = 0;
76
77 prepare_packed_git();
78 for (p = packed_git; p && found < 2; p = p->next) {
79 unsigned num = num_packed_objects(p);
80 unsigned first = 0, last = num;
81 while (first < last) {
82 unsigned mid = (first + last) / 2;
83 unsigned char now[20];
84 int cmp;
85
86 nth_packed_object_sha1(p, mid, now);
87 cmp = hashcmp(match, now);
88 if (!cmp) {
89 first = mid;
90 break;
91 }
92 if (cmp > 0) {
93 first = mid+1;
94 continue;
95 }
96 last = mid;
97 }
98 if (first < num) {
99 unsigned char now[20], next[20];
100 nth_packed_object_sha1(p, first, now);
101 if (match_sha(len, match, now)) {
102 if (nth_packed_object_sha1(p, first+1, next) ||
103 !match_sha(len, match, next)) {
104 /* unique within this pack */
105 if (!found) {
106 hashcpy(found_sha1, now);
107 found++;
108 }
109 else if (hashcmp(found_sha1, now)) {
110 found = 2;
111 break;
112 }
113 }
114 else {
115 /* not even unique within this pack */
116 found = 2;
117 break;
118 }
119 }
120 }
121 }
122 if (found == 1)
123 hashcpy(sha1, found_sha1);
124 return found;
125 }
126
127 #define SHORT_NAME_NOT_FOUND (-1)
128 #define SHORT_NAME_AMBIGUOUS (-2)
129
130 static int find_unique_short_object(int len, char *canonical,
131 unsigned char *res, unsigned char *sha1)
132 {
133 int has_unpacked, has_packed;
134 unsigned char unpacked_sha1[20], packed_sha1[20];
135
136 has_unpacked = find_short_object_filename(len, canonical, unpacked_sha1);
137 has_packed = find_short_packed_object(len, res, packed_sha1);
138 if (!has_unpacked && !has_packed)
139 return SHORT_NAME_NOT_FOUND;
140 if (1 < has_unpacked || 1 < has_packed)
141 return SHORT_NAME_AMBIGUOUS;
142 if (has_unpacked != has_packed) {
143 hashcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1));
144 return 0;
145 }
146 /* Both have unique ones -- do they match? */
147 if (hashcmp(packed_sha1, unpacked_sha1))
148 return SHORT_NAME_AMBIGUOUS;
149 hashcpy(sha1, packed_sha1);
150 return 0;
151 }
152
153 static int get_short_sha1(const char *name, int len, unsigned char *sha1,
154 int quietly)
155 {
156 int i, status;
157 char canonical[40];
158 unsigned char res[20];
159
160 if (len < MINIMUM_ABBREV)
161 return -1;
162 hashclr(res);
163 memset(canonical, 'x', 40);
164 for (i = 0; i < len ;i++) {
165 unsigned char c = name[i];
166 unsigned char val;
167 if (c >= '0' && c <= '9')
168 val = c - '0';
169 else if (c >= 'a' && c <= 'f')
170 val = c - 'a' + 10;
171 else if (c >= 'A' && c <='F') {
172 val = c - 'A' + 10;
173 c -= 'A' - 'a';
174 }
175 else
176 return -1;
177 canonical[i] = c;
178 if (!(i & 1))
179 val <<= 4;
180 res[i >> 1] |= val;
181 }
182
183 status = find_unique_short_object(i, canonical, res, sha1);
184 if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
185 return error("short SHA1 %.*s is ambiguous.", len, canonical);
186 return status;
187 }
188
189 const char *find_unique_abbrev(const unsigned char *sha1, int len)
190 {
191 int status, is_null;
192 static char hex[41];
193
194 is_null = is_null_sha1(sha1);
195 memcpy(hex, sha1_to_hex(sha1), 40);
196 if (len == 40 || !len)
197 return hex;
198 while (len < 40) {
199 unsigned char sha1_ret[20];
200 status = get_short_sha1(hex, len, sha1_ret, 1);
201 if (!status ||
202 (is_null && status != SHORT_NAME_AMBIGUOUS)) {
203 hex[len] = 0;
204 return hex;
205 }
206 if (status != SHORT_NAME_AMBIGUOUS)
207 return NULL;
208 len++;
209 }
210 return NULL;
211 }
212
213 static int ambiguous_path(const char *path, int len)
214 {
215 int slash = 1;
216 int cnt;
217
218 for (cnt = 0; cnt < len; cnt++) {
219 switch (*path++) {
220 case '\0':
221 break;
222 case '/':
223 if (slash)
224 break;
225 slash = 1;
226 continue;
227 case '.':
228 continue;
229 default:
230 slash = 0;
231 continue;
232 }
233 break;
234 }
235 return slash;
236 }
237
238 static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
239 {
240 static const char *fmt[] = {
241 "%.*s",
242 "refs/%.*s",
243 "refs/tags/%.*s",
244 "refs/heads/%.*s",
245 "refs/remotes/%.*s",
246 "refs/remotes/%.*s/HEAD",
247 NULL
248 };
249 static const char *warning = "warning: refname '%.*s' is ambiguous.\n";
250 const char **p, *ref;
251 char *real_ref = NULL;
252 int refs_found = 0, am;
253 unsigned long at_time = (unsigned long)-1;
254 unsigned char *this_result;
255 unsigned char sha1_from_ref[20];
256
257 if (len == 40 && !get_sha1_hex(str, sha1))
258 return 0;
259
260 /* At a given period of time? "@{2 hours ago}" */
261 for (am = 1; am < len - 1; am++) {
262 if (str[am] == '@' && str[am+1] == '{' && str[len-1] == '}') {
263 int date_len = len - am - 3;
264 char *date_spec = xmalloc(date_len + 1);
265 strlcpy(date_spec, str + am + 2, date_len + 1);
266 at_time = approxidate(date_spec);
267 free(date_spec);
268 len = am;
269 break;
270 }
271 }
272
273 /* Accept only unambiguous ref paths. */
274 if (ambiguous_path(str, len))
275 return -1;
276
277 for (p = fmt; *p; p++) {
278 this_result = refs_found ? sha1_from_ref : sha1;
279 ref = resolve_ref(mkpath(*p, len, str), this_result, 1, NULL);
280 if (ref) {
281 if (!refs_found++)
282 real_ref = xstrdup(ref);
283 if (!warn_ambiguous_refs)
284 break;
285 }
286 }
287
288 if (!refs_found)
289 return -1;
290
291 if (warn_ambiguous_refs && refs_found > 1)
292 fprintf(stderr, warning, len, str);
293
294 if (at_time != (unsigned long)-1) {
295 read_ref_at(
296 real_ref,
297 at_time,
298 sha1);
299 }
300
301 free(real_ref);
302 return 0;
303 }
304
305 static int get_sha1_1(const char *name, int len, unsigned char *sha1);
306
307 static int get_parent(const char *name, int len,
308 unsigned char *result, int idx)
309 {
310 unsigned char sha1[20];
311 int ret = get_sha1_1(name, len, sha1);
312 struct commit *commit;
313 struct commit_list *p;
314
315 if (ret)
316 return ret;
317 commit = lookup_commit_reference(sha1);
318 if (!commit)
319 return -1;
320 if (parse_commit(commit))
321 return -1;
322 if (!idx) {
323 hashcpy(result, commit->object.sha1);
324 return 0;
325 }
326 p = commit->parents;
327 while (p) {
328 if (!--idx) {
329 hashcpy(result, p->item->object.sha1);
330 return 0;
331 }
332 p = p->next;
333 }
334 return -1;
335 }
336
337 static int get_nth_ancestor(const char *name, int len,
338 unsigned char *result, int generation)
339 {
340 unsigned char sha1[20];
341 int ret = get_sha1_1(name, len, sha1);
342 if (ret)
343 return ret;
344
345 while (generation--) {
346 struct commit *commit = lookup_commit_reference(sha1);
347
348 if (!commit || parse_commit(commit) || !commit->parents)
349 return -1;
350 hashcpy(sha1, commit->parents->item->object.sha1);
351 }
352 hashcpy(result, sha1);
353 return 0;
354 }
355
356 static int peel_onion(const char *name, int len, unsigned char *sha1)
357 {
358 unsigned char outer[20];
359 const char *sp;
360 unsigned int expected_type = 0;
361 struct object *o;
362
363 /*
364 * "ref^{type}" dereferences ref repeatedly until you cannot
365 * dereference anymore, or you get an object of given type,
366 * whichever comes first. "ref^{}" means just dereference
367 * tags until you get a non-tag. "ref^0" is a shorthand for
368 * "ref^{commit}". "commit^{tree}" could be used to find the
369 * top-level tree of the given commit.
370 */
371 if (len < 4 || name[len-1] != '}')
372 return -1;
373
374 for (sp = name + len - 1; name <= sp; sp--) {
375 int ch = *sp;
376 if (ch == '{' && name < sp && sp[-1] == '^')
377 break;
378 }
379 if (sp <= name)
380 return -1;
381
382 sp++; /* beginning of type name, or closing brace for empty */
383 if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
384 expected_type = OBJ_COMMIT;
385 else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
386 expected_type = OBJ_TREE;
387 else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
388 expected_type = OBJ_BLOB;
389 else if (sp[0] == '}')
390 expected_type = OBJ_NONE;
391 else
392 return -1;
393
394 if (get_sha1_1(name, sp - name - 2, outer))
395 return -1;
396
397 o = parse_object(outer);
398 if (!o)
399 return -1;
400 if (!expected_type) {
401 o = deref_tag(o, name, sp - name - 2);
402 if (!o || (!o->parsed && !parse_object(o->sha1)))
403 return -1;
404 hashcpy(sha1, o->sha1);
405 }
406 else {
407 /* At this point, the syntax look correct, so
408 * if we do not get the needed object, we should
409 * barf.
410 */
411
412 while (1) {
413 if (!o || (!o->parsed && !parse_object(o->sha1)))
414 return -1;
415 if (o->type == expected_type) {
416 hashcpy(sha1, o->sha1);
417 return 0;
418 }
419 if (o->type == OBJ_TAG)
420 o = ((struct tag*) o)->tagged;
421 else if (o->type == OBJ_COMMIT)
422 o = &(((struct commit *) o)->tree->object);
423 else
424 return error("%.*s: expected %s type, but the object dereferences to %s type",
425 len, name, typename(expected_type),
426 typename(o->type));
427 if (!o->parsed)
428 parse_object(o->sha1);
429 }
430 }
431 return 0;
432 }
433
434 static int get_sha1_1(const char *name, int len, unsigned char *sha1)
435 {
436 int ret, has_suffix;
437 const char *cp;
438
439 /* "name~3" is "name^^^",
440 * "name~" and "name~0" are name -- not "name^0"!
441 * "name^" is not "name^0"; it is "name^1".
442 */
443 has_suffix = 0;
444 for (cp = name + len - 1; name <= cp; cp--) {
445 int ch = *cp;
446 if ('0' <= ch && ch <= '9')
447 continue;
448 if (ch == '~' || ch == '^')
449 has_suffix = ch;
450 break;
451 }
452
453 if (has_suffix) {
454 int num = 0;
455 int len1 = cp - name;
456 cp++;
457 while (cp < name + len)
458 num = num * 10 + *cp++ - '0';
459 if (has_suffix == '^') {
460 if (!num && len1 == len - 1)
461 num = 1;
462 return get_parent(name, len1, sha1, num);
463 }
464 /* else if (has_suffix == '~') -- goes without saying */
465 return get_nth_ancestor(name, len1, sha1, num);
466 }
467
468 ret = peel_onion(name, len, sha1);
469 if (!ret)
470 return 0;
471
472 ret = get_sha1_basic(name, len, sha1);
473 if (!ret)
474 return 0;
475 return get_short_sha1(name, len, sha1, 0);
476 }
477
478 /*
479 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
480 * notably "xyz^" for "parent of xyz"
481 */
482 int get_sha1(const char *name, unsigned char *sha1)
483 {
484 int ret, bracket_depth;
485 unsigned unused;
486 int namelen = strlen(name);
487 const char *cp;
488
489 prepare_alt_odb();
490 ret = get_sha1_1(name, namelen, sha1);
491 if (!ret)
492 return ret;
493 /* sha1:path --> object name of path in ent sha1
494 * :path -> object name of path in index
495 * :[0-3]:path -> object name of path in index at stage
496 */
497 if (name[0] == ':') {
498 int stage = 0;
499 struct cache_entry *ce;
500 int pos;
501 if (namelen < 3 ||
502 name[2] != ':' ||
503 name[1] < '0' || '3' < name[1])
504 cp = name + 1;
505 else {
506 stage = name[1] - '0';
507 cp = name + 3;
508 }
509 namelen = namelen - (cp - name);
510 if (!active_cache)
511 read_cache();
512 if (active_nr < 0)
513 return -1;
514 pos = cache_name_pos(cp, namelen);
515 if (pos < 0)
516 pos = -pos - 1;
517 while (pos < active_nr) {
518 ce = active_cache[pos];
519 if (ce_namelen(ce) != namelen ||
520 memcmp(ce->name, cp, namelen))
521 break;
522 if (ce_stage(ce) == stage) {
523 hashcpy(sha1, ce->sha1);
524 return 0;
525 }
526 pos++;
527 }
528 return -1;
529 }
530 for (cp = name, bracket_depth = 0; *cp; cp++) {
531 if (*cp == '{')
532 bracket_depth++;
533 else if (bracket_depth && *cp == '}')
534 bracket_depth--;
535 else if (!bracket_depth && *cp == ':')
536 break;
537 }
538 if (*cp == ':') {
539 unsigned char tree_sha1[20];
540 if (!get_sha1_1(name, cp-name, tree_sha1))
541 return get_tree_entry(tree_sha1, cp+1, sha1,
542 &unused);
543 }
544 return ret;
545 }