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         static const char *last_objdir;
  16         const char *objdir = get_object_directory();
  17
  18         if (!last_objdir || strcmp(last_objdir, objdir)) {
  19                 int objdir_len = strlen(objdir);
  20                 int entlen = objdir_len + 43;
  21                 if (fakeent)
  22                         free(fakeent);
  23                 fakeent = xmalloc(sizeof(*fakeent) + entlen);
  24                 memcpy(fakeent->base, objdir, objdir_len);
  25                 fakeent->name = fakeent->base + objdir_len + 1;
  26                 fakeent->name[-1] = '/';
  27                 if (last_objdir)
  28                         free((char *) last_objdir);
  29                 last_objdir = strdup(objdir);
  30         }
  31         fakeent->next = alt_odb_list;
  32
  33         sprintf(hex, "%.2s", name);
  34         for (alt = fakeent; alt && found < 2; alt = alt->next) {
  35                 struct dirent *de;
  36                 DIR *dir;
  37                 sprintf(alt->name, "%.2s/", name);
  38                 dir = opendir(alt->base);
  39                 if (!dir)
  40                         continue;
  41                 while ((de = readdir(dir)) != NULL) {
  42                         if (strlen(de->d_name) != 38)
  43                                 continue;
  44                         if (memcmp(de->d_name, name + 2, len - 2))
  45                                 continue;
  46                         if (!found) {
  47                                 memcpy(hex + 2, de->d_name, 38);
  48                                 found++;
  49                         }
  50                         else if (memcmp(hex + 2, de->d_name, 38)) {
  51                                 found = 2;
  52                                 break;
  53                         }
  54                 }
  55                 closedir(dir);
  56         }
  57         if (found == 1)
  58                 return get_sha1_hex(hex, sha1) == 0;
  59         return found;
  60 }
  61
  62 static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
  63 {
  64         do {
  65                 if (*a != *b)
  66                         return 0;
  67                 a++;
  68                 b++;
  69                 len -= 2;
  70         } while (len > 1);
  71         if (len)
  72                 if ((*a ^ *b) & 0xf0)
  73                         return 0;
  74         return 1;
  75 }
  76
  77 static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
  78 {
  79         struct packed_git *p;
  80         unsigned char found_sha1[20];
  81         int found = 0;
  82
  83         prepare_packed_git();
  84         for (p = packed_git; p && found < 2; p = p->next) {
  85                 unsigned num = num_packed_objects(p);
  86                 unsigned first = 0, last = num;
  87                 while (first < last) {
  88                         unsigned mid = (first + last) / 2;
  89                         unsigned char now[20];
  90                         int cmp;
  91
  92                         nth_packed_object_sha1(p, mid, now);
  93                         cmp = memcmp(match, now, 20);
  94                         if (!cmp) {
  95                                 first = mid;
  96                                 break;
  97                         }
  98                         if (cmp > 0) {
  99                                 first = mid+1;
 100                                 continue;
 101                         }
 102                         last = mid;
 103                 }
 104                 if (first < num) {
 105                         unsigned char now[20], next[20];
 106                         nth_packed_object_sha1(p, first, now);
 107                         if (match_sha(len, match, now)) {
 108                                 if (nth_packed_object_sha1(p, first+1, next) ||
 109                                     !match_sha(len, match, next)) {
 110                                         /* unique within this pack */
 111                                         if (!found) {
 112                                                 memcpy(found_sha1, now, 20);
 113                                                 found++;
 114                                         }
 115                                         else if (memcmp(found_sha1, now, 20)) {
 116                                                 found = 2;
 117                                                 break;
 118                                         }
 119                                 }
 120                                 else {
 121                                         /* not even unique within this pack */
 122                                         found = 2;
 123                                         break;
 124                                 }
 125                         }
 126                 }
 127         }
 128         if (found == 1)
 129                 memcpy(sha1, found_sha1, 20);
 130         return found;
 131 }
 132
 133 #define SHORT_NAME_NOT_FOUND (-1)
 134 #define SHORT_NAME_AMBIGUOUS (-2)
 135
 136 static int find_unique_short_object(int len, char *canonical,
 137                                     unsigned char *res, unsigned char *sha1)
 138 {
 139         int has_unpacked, has_packed;
 140         unsigned char unpacked_sha1[20], packed_sha1[20];
 141
 142         has_unpacked = find_short_object_filename(len, canonical, unpacked_sha1);
 143         has_packed = find_short_packed_object(len, res, packed_sha1);
 144         if (!has_unpacked && !has_packed)
 145                 return SHORT_NAME_NOT_FOUND;
 146         if (1 < has_unpacked || 1 < has_packed)
 147                 return SHORT_NAME_AMBIGUOUS;
 148         if (has_unpacked != has_packed) {
 149                 memcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1), 20);
 150                 return 0;
 151         }
 152         /* Both have unique ones -- do they match? */
 153         if (memcmp(packed_sha1, unpacked_sha1, 20))
 154                 return SHORT_NAME_AMBIGUOUS;
 155         memcpy(sha1, packed_sha1, 20);
 156         return 0;
 157 }
 158
 159 static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 160                           int quietly)
 161 {
 162         int i, status;
 163         char canonical[40];
 164         unsigned char res[20];
 165
 166         if (len < MINIMUM_ABBREV)
 167                 return -1;
 168         memset(res, 0, 20);
 169         memset(canonical, 'x', 40);
 170         for (i = 0; i < len ;i++) {
 171                 unsigned char c = name[i];
 172                 unsigned char val;
 173                 if (c >= '0' && c <= '9')
 174                         val = c - '0';
 175                 else if (c >= 'a' && c <= 'f')
 176                         val = c - 'a' + 10;
 177                 else if (c >= 'A' && c <='F') {
 178                         val = c - 'A' + 10;
 179                         c -= 'A' - 'a';
 180                 }
 181                 else
 182                         return -1;
 183                 canonical[i] = c;
 184                 if (!(i & 1))
 185                         val <<= 4;
 186                 res[i >> 1] |= val;
 187         }
 188
 189         status = find_unique_short_object(i, canonical, res, sha1);
 190         if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
 191                 return error("short SHA1 %.*s is ambiguous.", len, canonical);
 192         return status;
 193 }
 194
 195 const char *find_unique_abbrev(const unsigned char *sha1, int len)
 196 {
 197         int status, is_null;
 198         static char hex[41];
 199
 200         is_null = !memcmp(sha1, null_sha1, 20);
 201         memcpy(hex, sha1_to_hex(sha1), 40);
 202         if (len == 40)
 203                 return hex;
 204         while (len < 40) {
 205                 unsigned char sha1_ret[20];
 206                 status = get_short_sha1(hex, len, sha1_ret, 1);
 207                 if (!status ||
 208                     (is_null && status != SHORT_NAME_AMBIGUOUS)) {
 209                         hex[len] = 0;
 210                         return hex;
 211                 }
 212                 if (status != SHORT_NAME_AMBIGUOUS)
 213                         return NULL;
 214                 len++;
 215         }
 216         return NULL;
 217 }
 218
 219 static int ambiguous_path(const char *path, int len)
 220 {
 221         int slash = 1;
 222         int cnt;
 223
 224         for (cnt = 0; cnt < len; cnt++) {
 225                 switch (*path++) {
 226                 case '\0':
 227                         break;
 228                 case '/':
 229                         if (slash)
 230                                 break;
 231                         slash = 1;
 232                         continue;
 233                 case '.':
 234                         continue;
 235                 default:
 236                         slash = 0;
 237                         continue;
 238                 }
 239                 break;
 240         }
 241         return slash;
 242 }
 243
 244 static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 245 {
 246         static const char *fmt[] = {
 247                 "%.*s",
 248                 "refs/%.*s",
 249                 "refs/tags/%.*s",
 250                 "refs/heads/%.*s",
 251                 "refs/remotes/%.*s",
 252                 "refs/remotes/%.*s/HEAD",
 253                 NULL
 254         };
 255         static const char *warning = "warning: refname '%.*s' is ambiguous.\n";
 256         const char **p, *pathname;
 257         char *real_path = NULL;
 258         int refs_found = 0, am;
 259         unsigned long at_time = (unsigned long)-1;
 260         unsigned char *this_result;
 261         unsigned char sha1_from_ref[20];
 262
 263         if (len == 40 && !get_sha1_hex(str, sha1))
 264                 return 0;
 265
 266         /* At a given period of time? "@{2 hours ago}" */
 267         for (am = 1; am < len - 1; am++) {
 268                 if (str[am] == '@' && str[am+1] == '{' && str[len-1] == '}') {
 269                         int date_len = len - am - 3;
 270                         char *date_spec = xmalloc(date_len + 1);
 271                         strlcpy(date_spec, str + am + 2, date_len + 1);
 272                         at_time = approxidate(date_spec);
 273                         free(date_spec);
 274                         len = am;
 275                         break;
 276                 }
 277         }
 278
 279         /* Accept only unambiguous ref paths. */
 280         if (ambiguous_path(str, len))
 281                 return -1;
 282
 283         for (p = fmt; *p; p++) {
 284                 this_result = refs_found ? sha1_from_ref : sha1;
 285                 pathname = resolve_ref(git_path(*p, len, str), this_result, 1);
 286                 if (pathname) {
 287                         if (!refs_found++)
 288                                 real_path = strdup(pathname);
 289                         if (!warn_ambiguous_refs)
 290                                 break;
 291                 }
 292         }
 293
 294         if (!refs_found)
 295                 return -1;
 296
 297         if (warn_ambiguous_refs && refs_found > 1)
 298                 fprintf(stderr, warning, len, str);
 299
 300         if (at_time != (unsigned long)-1) {
 301                 read_ref_at(
 302                         real_path + strlen(git_path(".")) - 1,
 303                         at_time,
 304                         sha1);
 305         }
 306
 307         free(real_path);
 308         return 0;
 309 }
 310
 311 static int get_sha1_1(const char *name, int len, unsigned char *sha1);
 312
 313 static int get_parent(const char *name, int len,
 314                       unsigned char *result, int idx)
 315 {
 316         unsigned char sha1[20];
 317         int ret = get_sha1_1(name, len, sha1);
 318         struct commit *commit;
 319         struct commit_list *p;
 320
 321         if (ret)
 322                 return ret;
 323         commit = lookup_commit_reference(sha1);
 324         if (!commit)
 325                 return -1;
 326         if (parse_commit(commit))
 327                 return -1;
 328         if (!idx) {
 329                 memcpy(result, commit->object.sha1, 20);
 330                 return 0;
 331         }
 332         p = commit->parents;
 333         while (p) {
 334                 if (!--idx) {
 335                         memcpy(result, p->item->object.sha1, 20);
 336                         return 0;
 337                 }
 338                 p = p->next;
 339         }
 340         return -1;
 341 }
 342
 343 static int get_nth_ancestor(const char *name, int len,
 344                             unsigned char *result, int generation)
 345 {
 346         unsigned char sha1[20];
 347         int ret = get_sha1_1(name, len, sha1);
 348         if (ret)
 349                 return ret;
 350
 351         while (generation--) {
 352                 struct commit *commit = lookup_commit_reference(sha1);
 353
 354                 if (!commit || parse_commit(commit) || !commit->parents)
 355                         return -1;
 356                 memcpy(sha1, commit->parents->item->object.sha1, 20);
 357         }
 358         memcpy(result, sha1, 20);
 359         return 0;
 360 }
 361
 362 static int peel_onion(const char *name, int len, unsigned char *sha1)
 363 {
 364         unsigned char outer[20];
 365         const char *sp;
 366         unsigned int expected_type = 0;
 367         struct object *o;
 368
 369         /*
 370          * "ref^{type}" dereferences ref repeatedly until you cannot
 371          * dereference anymore, or you get an object of given type,
 372          * whichever comes first.  "ref^{}" means just dereference
 373          * tags until you get a non-tag.  "ref^0" is a shorthand for
 374          * "ref^{commit}".  "commit^{tree}" could be used to find the
 375          * top-level tree of the given commit.
 376          */
 377         if (len < 4 || name[len-1] != '}')
 378                 return -1;
 379
 380         for (sp = name + len - 1; name <= sp; sp--) {
 381                 int ch = *sp;
 382                 if (ch == '{' && name < sp && sp[-1] == '^')
 383                         break;
 384         }
 385         if (sp <= name)
 386                 return -1;
 387
 388         sp++; /* beginning of type name, or closing brace for empty */
 389         if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
 390                 expected_type = TYPE_COMMIT;
 391         else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
 392                 expected_type = TYPE_TREE;
 393         else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
 394                 expected_type = TYPE_BLOB;
 395         else if (sp[0] == '}')
 396                 expected_type = TYPE_NONE;
 397         else
 398                 return -1;
 399
 400         if (get_sha1_1(name, sp - name - 2, outer))
 401                 return -1;
 402
 403         o = parse_object(outer);
 404         if (!o)
 405                 return -1;
 406         if (!expected_type) {
 407                 o = deref_tag(o, name, sp - name - 2);
 408                 if (!o || (!o->parsed && !parse_object(o->sha1)))
 409                         return -1;
 410                 memcpy(sha1, o->sha1, 20);
 411         }
 412         else {
 413                 /* At this point, the syntax look correct, so
 414                  * if we do not get the needed object, we should
 415                  * barf.
 416                  */
 417
 418                 while (1) {
 419                         if (!o || (!o->parsed && !parse_object(o->sha1)))
 420                                 return -1;
 421                         if (o->type == expected_type) {
 422                                 memcpy(sha1, o->sha1, 20);
 423                                 return 0;
 424                         }
 425                         if (o->type == TYPE_TAG)
 426                                 o = ((struct tag*) o)->tagged;
 427                         else if (o->type == TYPE_COMMIT)
 428                                 o = &(((struct commit *) o)->tree->object);
 429                         else
 430                                 return error("%.*s: expected %s type, but the object dereferences to %s type",
 431                                              len, name, typename(expected_type),
 432                                              typename(o->type));
 433                         if (!o->parsed)
 434                                 parse_object(o->sha1);
 435                 }
 436         }
 437         return 0;
 438 }
 439
 440 static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 441 {
 442         int ret, has_suffix;
 443         const char *cp;
 444
 445         /* "name~3" is "name^^^",
 446          * "name~" and "name~0" are name -- not "name^0"!
 447          * "name^" is not "name^0"; it is "name^1".
 448          */
 449         has_suffix = 0;
 450         for (cp = name + len - 1; name <= cp; cp--) {
 451                 int ch = *cp;
 452                 if ('0' <= ch && ch <= '9')
 453                         continue;
 454                 if (ch == '~' || ch == '^')
 455                         has_suffix = ch;
 456                 break;
 457         }
 458
 459         if (has_suffix) {
 460                 int num = 0;
 461                 int len1 = cp - name;
 462                 cp++;
 463                 while (cp < name + len)
 464                         num = num * 10 + *cp++ - '0';
 465                 if (has_suffix == '^') {
 466                         if (!num && len1 == len - 1)
 467                                 num = 1;
 468                         return get_parent(name, len1, sha1, num);
 469                 }
 470                 /* else if (has_suffix == '~') -- goes without saying */
 471                 return get_nth_ancestor(name, len1, sha1, num);
 472         }
 473
 474         ret = peel_onion(name, len, sha1);
 475         if (!ret)
 476                 return 0;
 477
 478         ret = get_sha1_basic(name, len, sha1);
 479         if (!ret)
 480                 return 0;
 481         return get_short_sha1(name, len, sha1, 0);
 482 }
 483
 484 /*
 485  * This is like "get_sha1_basic()", except it allows "sha1 expressions",
 486  * notably "xyz^" for "parent of xyz"
 487  */
 488 int get_sha1(const char *name, unsigned char *sha1)
 489 {
 490         int ret, bracket_depth;
 491         unsigned unused;
 492         int namelen = strlen(name);
 493         const char *cp;
 494
 495         prepare_alt_odb();
 496         ret = get_sha1_1(name, namelen, sha1);
 497         if (!ret)
 498                 return ret;
 499         /* sha1:path --> object name of path in ent sha1
 500          * :path -> object name of path in index
 501          * :[0-3]:path -> object name of path in index at stage
 502          */
 503         if (name[0] == ':') {
 504                 int stage = 0;
 505                 struct cache_entry *ce;
 506                 int pos;
 507                 if (namelen < 3 ||
 508                     name[2] != ':' ||
 509                     name[1] < '0' || '3' < name[1])
 510                         cp = name + 1;
 511                 else {
 512                         stage = name[1] - '0';
 513                         cp = name + 3;
 514                 }
 515                 namelen = namelen - (cp - name);
 516                 if (!active_cache)
 517                         read_cache();
 518                 if (active_nr < 0)
 519                         return -1;
 520                 pos = cache_name_pos(cp, namelen);
 521                 if (pos < 0)
 522                         pos = -pos - 1;
 523                 while (pos < active_nr) {
 524                         ce = active_cache[pos];
 525                         if (ce_namelen(ce) != namelen ||
 526                             memcmp(ce->name, cp, namelen))
 527                                 break;
 528                         if (ce_stage(ce) == stage) {
 529                                 memcpy(sha1, ce->sha1, 20);
 530                                 return 0;
 531                         }
 532                         pos++;
 533                 }
 534                 return -1;
 535         }
 536         for (cp = name, bracket_depth = 0; *cp; cp++) {
 537                 if (*cp == '{')
 538                         bracket_depth++;
 539                 else if (bracket_depth && *cp == '}')
 540                         bracket_depth--;
 541                 else if (!bracket_depth && *cp == ':')
 542                         break;
 543         }
 544         if (*cp == ':') {
 545                 unsigned char tree_sha1[20];
 546                 if (!get_sha1_1(name, cp-name, tree_sha1))
 547                         return get_tree_entry(tree_sha1, cp+1, sha1,
 548                                               &unused);
 549         }
 550         return ret;
 551 }