1#include "cache.h"
2#include "tag.h"
3#include "commit.h"
4#include "tree.h"
5#include "blob.h"
6static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
8{
9 struct alternate_object_database *alt;
10 char hex[40];
11 int found = 0;
12 static struct alternate_object_database *fakeent;
13 if (!fakeent) {
15 const char *objdir = get_object_directory();
16 int objdir_len = strlen(objdir);
17 int entlen = objdir_len + 43;
18 fakeent = xmalloc(sizeof(*fakeent) + entlen);
19 memcpy(fakeent->base, objdir, objdir_len);
20 fakeent->name = fakeent->base + objdir_len + 1;
21 fakeent->name[-1] = '/';
22 }
23 fakeent->next = alt_odb_list;
24 sprintf(hex, "%.2s", name);
26 for (alt = fakeent; alt && found < 2; alt = alt->next) {
27 struct dirent *de;
28 DIR *dir;
29 sprintf(alt->name, "%.2s/", name);
30 dir = opendir(alt->base);
31 if (!dir)
32 continue;
33 while ((de = readdir(dir)) != NULL) {
34 if (strlen(de->d_name) != 38)
35 continue;
36 if (memcmp(de->d_name, name + 2, len - 2))
37 continue;
38 if (!found) {
39 memcpy(hex + 2, de->d_name, 38);
40 found++;
41 }
42 else if (memcmp(hex + 2, de->d_name, 38)) {
43 found = 2;
44 break;
45 }
46 }
47 closedir(dir);
48 }
49 if (found == 1)
50 return get_sha1_hex(hex, sha1) == 0;
51 return found;
52}
53static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
55{
56 do {
57 if (*a != *b)
58 return 0;
59 a++;
60 b++;
61 len -= 2;
62 } while (len > 1);
63 if (len)
64 if ((*a ^ *b) & 0xf0)
65 return 0;
66 return 1;
67}
68static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
70{
71 struct packed_git *p;
72 unsigned char found_sha1[20];
73 int found = 0;
74 prepare_packed_git();
76 for (p = packed_git; p && found < 2; p = p->next) {
77 unsigned num = num_packed_objects(p);
78 unsigned first = 0, last = num;
79 while (first < last) {
80 unsigned mid = (first + last) / 2;
81 unsigned char now[20];
82 int cmp;
83 nth_packed_object_sha1(p, mid, now);
85 cmp = memcmp(match, now, 20);
86 if (!cmp) {
87 first = mid;
88 break;
89 }
90 if (cmp > 0) {
91 first = mid+1;
92 continue;
93 }
94 last = mid;
95 }
96 if (first < num) {
97 unsigned char now[20], next[20];
98 nth_packed_object_sha1(p, first, now);
99 if (match_sha(len, match, now)) {
100 if (nth_packed_object_sha1(p, first+1, next) ||
101 !match_sha(len, match, next)) {
102 /* unique within this pack */
103 if (!found) {
104 memcpy(found_sha1, now, 20);
105 found++;
106 }
107 else if (memcmp(found_sha1, now, 20)) {
108 found = 2;
109 break;
110 }
111 }
112 else {
113 /* not even unique within this pack */
114 found = 2;
115 break;
116 }
117 }
118 }
119 }
120 if (found == 1)
121 memcpy(sha1, found_sha1, 20);
122 return found;
123}
124#define SHORT_NAME_NOT_FOUND (-1)
126#define SHORT_NAME_AMBIGUOUS (-2)
127static int find_unique_short_object(int len, char *canonical,
129 unsigned char *res, unsigned char *sha1)
130{
131 int has_unpacked, has_packed;
132 unsigned char unpacked_sha1[20], packed_sha1[20];
133 has_unpacked = find_short_object_filename(len, canonical, unpacked_sha1);
135 has_packed = find_short_packed_object(len, res, packed_sha1);
136 if (!has_unpacked && !has_packed)
137 return SHORT_NAME_NOT_FOUND;
138 if (1 < has_unpacked || 1 < has_packed)
139 return SHORT_NAME_AMBIGUOUS;
140 if (has_unpacked != has_packed) {
141 memcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1), 20);
142 return 0;
143 }
144 /* Both have unique ones -- do they match? */
145 if (memcmp(packed_sha1, unpacked_sha1, 20))
146 return SHORT_NAME_AMBIGUOUS;
147 memcpy(sha1, packed_sha1, 20);
148 return 0;
149}
150static int get_short_sha1(const char *name, int len, unsigned char *sha1,
152 int quietly)
153{
154 int i, status;
155 char canonical[40];
156 unsigned char res[20];
157 if (len < MINIMUM_ABBREV)
159 return -1;
160 memset(res, 0, 20);
161 memset(canonical, 'x', 40);
162 for (i = 0; i < len ;i++) {
163 unsigned char c = name[i];
164 unsigned char val;
165 if (c >= '0' && c <= '9')
166 val = c - '0';
167 else if (c >= 'a' && c <= 'f')
168 val = c - 'a' + 10;
169 else if (c >= 'A' && c <='F') {
170 val = c - 'A' + 10;
171 c -= 'A' - 'a';
172 }
173 else
174 return -1;
175 canonical[i] = c;
176 if (!(i & 1))
177 val <<= 4;
178 res[i >> 1] |= val;
179 }
180 status = find_unique_short_object(i, canonical, res, sha1);
182 if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
183 return error("short SHA1 %.*s is ambiguous.", len, canonical);
184 return status;
185}
186const char *find_unique_abbrev(const unsigned char *sha1, int len)
188{
189 int status, is_null;
190 static char hex[41];
191 is_null = !memcmp(sha1, null_sha1, 20);
193 memcpy(hex, sha1_to_hex(sha1), 40);
194 if (len == 40)
195 return hex;
196 while (len < 40) {
197 unsigned char sha1_ret[20];
198 status = get_short_sha1(hex, len, sha1_ret, 1);
199 if (!status ||
200 (is_null && status != SHORT_NAME_AMBIGUOUS)) {
201 hex[len] = 0;
202 return hex;
203 }
204 if (status != SHORT_NAME_AMBIGUOUS)
205 return NULL;
206 len++;
207 }
208 return NULL;
209}
210static int ambiguous_path(const char *path, int len)
212{
213 int slash = 1;
214 int cnt;
215 for (cnt = 0; cnt < len; cnt++) {
217 switch (*path++) {
218 case '\0':
219 break;
220 case '/':
221 if (slash)
222 break;
223 slash = 1;
224 continue;
225 case '.':
226 continue;
227 default:
228 slash = 0;
229 continue;
230 }
231 break;
232 }
233 return slash;
234}
235static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
237{
238 static const char *fmt[] = {
239 "%.*s",
240 "refs/%.*s",
241 "refs/tags/%.*s",
242 "refs/heads/%.*s",
243 "refs/remotes/%.*s",
244 "refs/remotes/%.*s/HEAD",
245 NULL
246 };
247 const char **p;
248 const char *warning = "warning: refname '%.*s' is ambiguous.\n";
249 char *pathname;
250 int already_found = 0;
251 unsigned char *this_result;
252 unsigned char sha1_from_ref[20];
253 if (len == 40 && !get_sha1_hex(str, sha1))
255 return 0;
256 /* Accept only unambiguous ref paths. */
258 if (ambiguous_path(str, len))
259 return -1;
260 for (p = fmt; *p; p++) {
262 this_result = already_found ? sha1_from_ref : sha1;
263 pathname = git_path(*p, len, str);
264 if (!read_ref(pathname, this_result)) {
265 if (warn_ambiguous_refs) {
266 if (already_found)
267 fprintf(stderr, warning, len, str);
268 already_found++;
269 }
270 else
271 return 0;
272 }
273 }
274 if (already_found)
275 return 0;
276 return -1;
277}
278static int get_sha1_1(const char *name, int len, unsigned char *sha1);
280static int get_parent(const char *name, int len,
282 unsigned char *result, int idx)
283{
284 unsigned char sha1[20];
285 int ret = get_sha1_1(name, len, sha1);
286 struct commit *commit;
287 struct commit_list *p;
288 if (ret)
290 return ret;
291 commit = lookup_commit_reference(sha1);
292 if (!commit)
293 return -1;
294 if (parse_commit(commit))
295 return -1;
296 if (!idx) {
297 memcpy(result, commit->object.sha1, 20);
298 return 0;
299 }
300 p = commit->parents;
301 while (p) {
302 if (!--idx) {
303 memcpy(result, p->item->object.sha1, 20);
304 return 0;
305 }
306 p = p->next;
307 }
308 return -1;
309}
310static int get_nth_ancestor(const char *name, int len,
312 unsigned char *result, int generation)
313{
314 unsigned char sha1[20];
315 int ret = get_sha1_1(name, len, sha1);
316 if (ret)
317 return ret;
318 while (generation--) {
320 struct commit *commit = lookup_commit_reference(sha1);
321 if (!commit || parse_commit(commit) || !commit->parents)
323 return -1;
324 memcpy(sha1, commit->parents->item->object.sha1, 20);
325 }
326 memcpy(result, sha1, 20);
327 return 0;
328}
329static int peel_onion(const char *name, int len, unsigned char *sha1)
331{
332 unsigned char outer[20];
333 const char *sp;
334 const char *type_string = NULL;
335 struct object *o;
336 /*
338 * "ref^{type}" dereferences ref repeatedly until you cannot
339 * dereference anymore, or you get an object of given type,
340 * whichever comes first. "ref^{}" means just dereference
341 * tags until you get a non-tag. "ref^0" is a shorthand for
342 * "ref^{commit}". "commit^{tree}" could be used to find the
343 * top-level tree of the given commit.
344 */
345 if (len < 4 || name[len-1] != '}')
346 return -1;
347 for (sp = name + len - 1; name <= sp; sp--) {
349 int ch = *sp;
350 if (ch == '{' && name < sp && sp[-1] == '^')
351 break;
352 }
353 if (sp <= name)
354 return -1;
355 sp++; /* beginning of type name, or closing brace for empty */
357 if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
358 type_string = commit_type;
359 else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
360 type_string = tree_type;
361 else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
362 type_string = blob_type;
363 else if (sp[0] == '}')
364 type_string = NULL;
365 else
366 return -1;
367 if (get_sha1_1(name, sp - name - 2, outer))
369 return -1;
370 o = parse_object(outer);
372 if (!o)
373 return -1;
374 if (!type_string) {
375 o = deref_tag(o, name, sp - name - 2);
376 if (!o || (!o->parsed && !parse_object(o->sha1)))
377 return -1;
378 memcpy(sha1, o->sha1, 20);
379 }
380 else {
381 /* At this point, the syntax look correct, so
382 * if we do not get the needed object, we should
383 * barf.
384 */
385 while (1) {
387 if (!o || (!o->parsed && !parse_object(o->sha1)))
388 return -1;
389 if (o->type == type_string) {
390 memcpy(sha1, o->sha1, 20);
391 return 0;
392 }
393 if (o->type == tag_type)
394 o = ((struct tag*) o)->tagged;
395 else if (o->type == commit_type)
396 o = &(((struct commit *) o)->tree->object);
397 else
398 return error("%.*s: expected %s type, but the object dereferences to %s type",
399 len, name, type_string,
400 o->type);
401 if (!o->parsed)
402 parse_object(o->sha1);
403 }
404 }
405 return 0;
406}
407static int get_sha1_1(const char *name, int len, unsigned char *sha1)
409{
410 int ret, has_suffix;
411 const char *cp;
412 /* "name~3" is "name^^^",
414 * "name~" and "name~0" are name -- not "name^0"!
415 * "name^" is not "name^0"; it is "name^1".
416 */
417 has_suffix = 0;
418 for (cp = name + len - 1; name <= cp; cp--) {
419 int ch = *cp;
420 if ('0' <= ch && ch <= '9')
421 continue;
422 if (ch == '~' || ch == '^')
423 has_suffix = ch;
424 break;
425 }
426 if (has_suffix) {
428 int num = 0;
429 int len1 = cp - name;
430 cp++;
431 while (cp < name + len)
432 num = num * 10 + *cp++ - '0';
433 if (has_suffix == '^') {
434 if (!num && len1 == len - 1)
435 num = 1;
436 return get_parent(name, len1, sha1, num);
437 }
438 /* else if (has_suffix == '~') -- goes without saying */
439 return get_nth_ancestor(name, len1, sha1, num);
440 }
441 ret = peel_onion(name, len, sha1);
443 if (!ret)
444 return 0;
445 ret = get_sha1_basic(name, len, sha1);
447 if (!ret)
448 return 0;
449 return get_short_sha1(name, len, sha1, 0);
450}
451/*
453 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
454 * notably "xyz^" for "parent of xyz"
455 */
456int get_sha1(const char *name, unsigned char *sha1)
457{
458 prepare_alt_odb();
459 return get_sha1_1(name, strlen(name), sha1);
460}