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"
8static 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 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 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}
55static 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}
70static 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 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 nth_packed_object_sha1(p, mid, now);
87 cmp = memcmp(match, now, 20);
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 memcpy(found_sha1, now, 20);
107 found++;
108 }
109 else if (memcmp(found_sha1, now, 20)) {
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 memcpy(sha1, found_sha1, 20);
124 return found;
125}
126#define SHORT_NAME_NOT_FOUND (-1)
128#define SHORT_NAME_AMBIGUOUS (-2)
129static 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 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 memcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1), 20);
144 return 0;
145 }
146 /* Both have unique ones -- do they match? */
147 if (memcmp(packed_sha1, unpacked_sha1, 20))
148 return SHORT_NAME_AMBIGUOUS;
149 memcpy(sha1, packed_sha1, 20);
150 return 0;
151}
152static 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 if (len < MINIMUM_ABBREV)
161 return -1;
162 memset(res, 0, 20);
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 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}
188const char *find_unique_abbrev(const unsigned char *sha1, int len)
190{
191 int status, is_null;
192 static char hex[41];
193 is_null = !memcmp(sha1, null_sha1, 20);
195 memcpy(hex, sha1_to_hex(sha1), 40);
196 if (len == 40)
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}
212static int ambiguous_path(const char *path, int len)
214{
215 int slash = 1;
216 int cnt;
217 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}
237static 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, *pathname;
251 char *real_path = 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 if (len == 40 && !get_sha1_hex(str, sha1))
258 return 0;
259 /* 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 strncpy(date_spec, str + am + 2, date_len);
266 date_spec[date_len] = 0;
267 at_time = approxidate(date_spec);
268 free(date_spec);
269 len = am;
270 break;
271 }
272 }
273 /* Accept only unambiguous ref paths. */
275 if (ambiguous_path(str, len))
276 return -1;
277 for (p = fmt; *p; p++) {
279 this_result = refs_found ? sha1_from_ref : sha1;
280 pathname = resolve_ref(git_path(*p, len, str), this_result, 1);
281 if (pathname) {
282 if (!refs_found++)
283 real_path = strdup(pathname);
284 if (!warn_ambiguous_refs)
285 break;
286 }
287 }
288 if (!refs_found)
290 return -1;
291 if (warn_ambiguous_refs && refs_found > 1)
293 fprintf(stderr, warning, len, str);
294 if (at_time != (unsigned long)-1) {
296 read_ref_at(
297 real_path + strlen(git_path(".")) - 1,
298 at_time,
299 sha1);
300 }
301 free(real_path);
303 return 0;
304}
305static int get_sha1_1(const char *name, int len, unsigned char *sha1);
307static int get_parent(const char *name, int len,
309 unsigned char *result, int idx)
310{
311 unsigned char sha1[20];
312 int ret = get_sha1_1(name, len, sha1);
313 struct commit *commit;
314 struct commit_list *p;
315 if (ret)
317 return ret;
318 commit = lookup_commit_reference(sha1);
319 if (!commit)
320 return -1;
321 if (parse_commit(commit))
322 return -1;
323 if (!idx) {
324 memcpy(result, commit->object.sha1, 20);
325 return 0;
326 }
327 p = commit->parents;
328 while (p) {
329 if (!--idx) {
330 memcpy(result, p->item->object.sha1, 20);
331 return 0;
332 }
333 p = p->next;
334 }
335 return -1;
336}
337static int get_nth_ancestor(const char *name, int len,
339 unsigned char *result, int generation)
340{
341 unsigned char sha1[20];
342 int ret = get_sha1_1(name, len, sha1);
343 if (ret)
344 return ret;
345 while (generation--) {
347 struct commit *commit = lookup_commit_reference(sha1);
348 if (!commit || parse_commit(commit) || !commit->parents)
350 return -1;
351 memcpy(sha1, commit->parents->item->object.sha1, 20);
352 }
353 memcpy(result, sha1, 20);
354 return 0;
355}
356static int peel_onion(const char *name, int len, unsigned char *sha1)
358{
359 unsigned char outer[20];
360 const char *sp;
361 const char *type_string = NULL;
362 struct object *o;
363 /*
365 * "ref^{type}" dereferences ref repeatedly until you cannot
366 * dereference anymore, or you get an object of given type,
367 * whichever comes first. "ref^{}" means just dereference
368 * tags until you get a non-tag. "ref^0" is a shorthand for
369 * "ref^{commit}". "commit^{tree}" could be used to find the
370 * top-level tree of the given commit.
371 */
372 if (len < 4 || name[len-1] != '}')
373 return -1;
374 for (sp = name + len - 1; name <= sp; sp--) {
376 int ch = *sp;
377 if (ch == '{' && name < sp && sp[-1] == '^')
378 break;
379 }
380 if (sp <= name)
381 return -1;
382 sp++; /* beginning of type name, or closing brace for empty */
384 if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
385 type_string = commit_type;
386 else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
387 type_string = tree_type;
388 else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
389 type_string = blob_type;
390 else if (sp[0] == '}')
391 type_string = NULL;
392 else
393 return -1;
394 if (get_sha1_1(name, sp - name - 2, outer))
396 return -1;
397 o = parse_object(outer);
399 if (!o)
400 return -1;
401 if (!type_string) {
402 o = deref_tag(o, name, sp - name - 2);
403 if (!o || (!o->parsed && !parse_object(o->sha1)))
404 return -1;
405 memcpy(sha1, o->sha1, 20);
406 }
407 else {
408 /* At this point, the syntax look correct, so
409 * if we do not get the needed object, we should
410 * barf.
411 */
412 while (1) {
414 if (!o || (!o->parsed && !parse_object(o->sha1)))
415 return -1;
416 if (o->type == type_string) {
417 memcpy(sha1, o->sha1, 20);
418 return 0;
419 }
420 if (o->type == tag_type)
421 o = ((struct tag*) o)->tagged;
422 else if (o->type == commit_type)
423 o = &(((struct commit *) o)->tree->object);
424 else
425 return error("%.*s: expected %s type, but the object dereferences to %s type",
426 len, name, type_string,
427 o->type);
428 if (!o->parsed)
429 parse_object(o->sha1);
430 }
431 }
432 return 0;
433}
434static int get_sha1_1(const char *name, int len, unsigned char *sha1)
436{
437 int ret, has_suffix;
438 const char *cp;
439 /* "name~3" is "name^^^",
441 * "name~" and "name~0" are name -- not "name^0"!
442 * "name^" is not "name^0"; it is "name^1".
443 */
444 has_suffix = 0;
445 for (cp = name + len - 1; name <= cp; cp--) {
446 int ch = *cp;
447 if ('0' <= ch && ch <= '9')
448 continue;
449 if (ch == '~' || ch == '^')
450 has_suffix = ch;
451 break;
452 }
453 if (has_suffix) {
455 int num = 0;
456 int len1 = cp - name;
457 cp++;
458 while (cp < name + len)
459 num = num * 10 + *cp++ - '0';
460 if (has_suffix == '^') {
461 if (!num && len1 == len - 1)
462 num = 1;
463 return get_parent(name, len1, sha1, num);
464 }
465 /* else if (has_suffix == '~') -- goes without saying */
466 return get_nth_ancestor(name, len1, sha1, num);
467 }
468 ret = peel_onion(name, len, sha1);
470 if (!ret)
471 return 0;
472 ret = get_sha1_basic(name, len, sha1);
474 if (!ret)
475 return 0;
476 return get_short_sha1(name, len, sha1, 0);
477}
478/*
480 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
481 * notably "xyz^" for "parent of xyz"
482 */
483int get_sha1(const char *name, unsigned char *sha1)
484{
485 int ret, bracket_depth;
486 unsigned unused;
487 int namelen = strlen(name);
488 const char *cp;
489 prepare_alt_odb();
491 ret = get_sha1_1(name, namelen, sha1);
492 if (!ret)
493 return ret;
494 /* sha1:path --> object name of path in ent sha1
495 * :path -> object name of path in index
496 * :[0-3]:path -> object name of path in index at stage
497 */
498 if (name[0] == ':') {
499 int stage = 0;
500 struct cache_entry *ce;
501 int pos;
502 if (namelen < 3 ||
503 name[2] != ':' ||
504 name[1] < '0' || '3' < name[1])
505 cp = name + 1;
506 else {
507 stage = name[1] - '0';
508 cp = name + 3;
509 }
510 namelen = namelen - (cp - name);
511 if (!active_cache)
512 read_cache();
513 if (active_nr < 0)
514 return -1;
515 pos = cache_name_pos(cp, namelen);
516 if (pos < 0)
517 pos = -pos - 1;
518 while (pos < active_nr) {
519 ce = active_cache[pos];
520 if (ce_namelen(ce) != namelen ||
521 memcmp(ce->name, cp, namelen))
522 break;
523 if (ce_stage(ce) == stage) {
524 memcpy(sha1, ce->sha1, 20);
525 return 0;
526 }
527 pos++;
528 }
529 return -1;
530 }
531 for (cp = name, bracket_depth = 0; *cp; cp++) {
532 if (*cp == '{')
533 bracket_depth++;
534 else if (bracket_depth && *cp == '}')
535 bracket_depth--;
536 else if (!bracket_depth && *cp == ':')
537 break;
538 }
539 if (*cp == ':') {
540 unsigned char tree_sha1[20];
541 if (!get_sha1_1(name, cp-name, tree_sha1))
542 return get_tree_entry(tree_sha1, cp+1, sha1,
543 &unused);
544 }
545 return ret;
546}