7 static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
9 struct alternate_object_database *alt;
12 static struct alternate_object_database *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] = '/';
23 fakeent->next = alt_odb_list;
25 sprintf(hex, "%.2s", name);
26 for (alt = fakeent; alt && found < 2; alt = alt->next) {
29 sprintf(alt->name, "%.2s/", name);
30 dir = opendir(alt->base);
33 while ((de = readdir(dir)) != NULL) {
34 if (strlen(de->d_name) != 38)
36 if (memcmp(de->d_name, name + 2, len - 2))
39 memcpy(hex + 2, de->d_name, 38);
42 else if (memcmp(hex + 2, de->d_name, 38)) {
50 return get_sha1_hex(hex, sha1) == 0;
54 static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
69 static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
72 unsigned char found_sha1[20];
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];
84 nth_packed_object_sha1(p, mid, now);
85 cmp = memcmp(match, now, 20);
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 */
104 memcpy(found_sha1, now, 20);
107 else if (memcmp(found_sha1, now, 20)) {
113 /* not even unique within this pack */
121 memcpy(sha1, found_sha1, 20);
125 static int find_unique_short_object(int len, char *canonical,
126 unsigned char *res, unsigned char *sha1)
128 int has_unpacked, has_packed;
129 unsigned char unpacked_sha1[20], packed_sha1[20];
131 has_unpacked = find_short_object_filename(len, canonical, unpacked_sha1);
132 has_packed = find_short_packed_object(len, res, packed_sha1);
133 if (!has_unpacked && !has_packed)
135 if (1 < has_unpacked || 1 < has_packed)
136 return error("short SHA1 %.*s is ambiguous.", len, canonical);
137 if (has_unpacked != has_packed) {
138 memcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1), 20);
141 /* Both have unique ones -- do they match? */
142 if (memcmp(packed_sha1, unpacked_sha1, 20))
143 return error("short SHA1 %.*s is ambiguous.", len, canonical);
144 memcpy(sha1, packed_sha1, 20);
148 static int get_short_sha1(const char *name, int len, unsigned char *sha1)
152 unsigned char res[20];
157 memset(canonical, 'x', 40);
158 for (i = 0; i < len ;i++) {
159 unsigned char c = name[i];
161 if (c >= '0' && c <= '9')
163 else if (c >= 'a' && c <= 'f')
165 else if (c >= 'A' && c <='F') {
177 return find_unique_short_object(i, canonical, res, sha1);
180 static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
182 static const char *prefix[] = {
191 if (len == 40 && !get_sha1_hex(str, sha1))
194 for (p = prefix; *p; p++) {
195 char *pathname = git_path("%s/%.*s", *p, len, str);
196 if (!read_ref(pathname, sha1))
203 static int get_sha1_1(const char *name, int len, unsigned char *sha1);
205 static int get_parent(const char *name, int len,
206 unsigned char *result, int idx)
208 unsigned char sha1[20];
209 int ret = get_sha1_1(name, len, sha1);
210 struct commit *commit;
211 struct commit_list *p;
215 commit = lookup_commit_reference(sha1);
218 if (parse_commit(commit))
221 memcpy(result, commit->object.sha1, 20);
227 memcpy(result, p->item->object.sha1, 20);
235 static int get_nth_ancestor(const char *name, int len,
236 unsigned char *result, int generation)
238 unsigned char sha1[20];
239 int ret = get_sha1_1(name, len, sha1);
243 while (generation--) {
244 struct commit *commit = lookup_commit_reference(sha1);
246 if (!commit || parse_commit(commit) || !commit->parents)
248 memcpy(sha1, commit->parents->item->object.sha1, 20);
250 memcpy(result, sha1, 20);
254 static int peel_onion(const char *name, int len, unsigned char *sha1)
256 unsigned char outer[20];
258 const char *type_string = NULL;
262 * "ref^{type}" dereferences ref repeatedly until you cannot
263 * dereference anymore, or you get an object of given type,
264 * whichever comes first. "ref^{}" means just dereference
265 * tags until you get a non-tag. "ref^0" is a shorthand for
266 * "ref^{commit}". "commit^{tree}" could be used to find the
267 * top-level tree of the given commit.
269 if (len < 4 || name[len-1] != '}')
272 for (sp = name + len - 1; name <= sp; sp--) {
274 if (ch == '{' && name < sp && sp[-1] == '^')
280 sp++; /* beginning of type name, or closing brace for empty */
281 if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
282 type_string = commit_type;
283 else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
284 type_string = tree_type;
285 else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
286 type_string = blob_type;
287 else if (sp[0] == '}')
292 if (get_sha1_1(name, sp - name - 2, outer))
295 o = parse_object(outer);
300 memcpy(sha1, o->sha1, 20);
303 /* At this point, the syntax look correct, so
304 * if we do not get the needed object, we should
311 if (o->type == type_string) {
312 memcpy(sha1, o->sha1, 20);
315 if (o->type == tag_type)
316 o = ((struct tag*) o)->tagged;
317 else if (o->type == commit_type)
318 o = &(((struct commit *) o)->tree->object);
320 return error("%.*s: expected %s type, but the object dereferences to %s type",
321 len, name, type_string,
324 parse_object(o->sha1);
330 static int get_sha1_1(const char *name, int len, unsigned char *sha1)
335 /* foo^[0-9] or foo^ (== foo^1); we do not do more than 9 parents. */
336 if (len > 2 && name[len-2] == '^' &&
337 name[len-1] >= '0' && name[len-1] <= '9') {
338 parent = name[len-1] - '0';
341 else if (len > 1 && name[len-1] == '^') {
348 return get_parent(name, len, sha1, parent);
350 /* "name~3" is "name^^^",
351 * "name~12" is "name^^^^^^^^^^^^", and
352 * "name~" and "name~0" are name -- not "name^0"!
355 for (cp = name + len - 1; name <= cp; cp--) {
357 if ('0' <= ch && ch <= '9')
363 if (!parent && *cp == '~') {
364 int len1 = cp - name;
366 while (cp < name + len)
367 parent = parent * 10 + *cp++ - '0';
368 return get_nth_ancestor(name, len1, sha1, parent);
371 ret = peel_onion(name, len, sha1);
375 ret = get_sha1_basic(name, len, sha1);
378 return get_short_sha1(name, len, sha1);
382 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
383 * notably "xyz^" for "parent of xyz"
385 int get_sha1(const char *name, unsigned char *sha1)
388 return get_sha1_1(name, strlen(name), sha1);