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 = 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
 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                 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 }
 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         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
 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 = !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 }
 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, *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
 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                         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
 274         /* Accept only unambiguous ref paths. */
 275         if (ambiguous_path(str, len))
 276                 return -1;
 277
 278         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
 289         if (!refs_found)
 290                 return -1;
 291
 292         if (warn_ambiguous_refs && refs_found > 1)
 293                 fprintf(stderr, warning, len, str);
 294
 295         if (at_time != (unsigned long)-1) {
 296                 read_ref_at(
 297                         real_path + strlen(git_path(".")) - 1,
 298                         at_time,
 299                         sha1);
 300         }
 301
 302         free(real_path);
 303         return 0;
 304 }
 305
 306 static int get_sha1_1(const char *name, int len, unsigned char *sha1);
 307
 308 static 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
 316         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 }
 337
 338 static 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
 346         while (generation--) {
 347                 struct commit *commit = lookup_commit_reference(sha1);
 348
 349                 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 }
 356
 357 static 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
 364         /*
 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
 375         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
 383         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
 395         if (get_sha1_1(name, sp - name - 2, outer))
 396                 return -1;
 397
 398         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
 413                 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 }
 434
 435 static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 436 {
 437         int ret, has_suffix;
 438         const char *cp;
 439
 440         /* "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
 454         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
 469         ret = peel_onion(name, len, sha1);
 470         if (!ret)
 471                 return 0;
 472
 473         ret = get_sha1_basic(name, len, sha1);
 474         if (!ret)
 475                 return 0;
 476         return get_short_sha1(name, len, sha1, 0);
 477 }
 478
 479 /*
 480  * This is like "get_sha1_basic()", except it allows "sha1 expressions",
 481  * notably "xyz^" for "parent of xyz"
 482  */
 483 int 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
 490         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 }