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 = hashcmp(match, now);
  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                                                 hashcpy(found_sha1, now);
 107                                                 found++;
 108                                         }
 109                                         else if (hashcmp(found_sha1, now)) {
 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                 hashcpy(sha1, found_sha1);
 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                 hashcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1));
 144                 return 0;
 145         }
 146         /* Both have unique ones -- do they match? */
 147         if (hashcmp(packed_sha1, unpacked_sha1))
 148                 return SHORT_NAME_AMBIGUOUS;
 149         hashcpy(sha1, packed_sha1);
 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 || len > 40)
 161                 return -1;
 162         hashclr(res);
 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 = is_null_sha1(sha1);
 195         memcpy(hex, sha1_to_hex(sha1), 40);
 196         if (len == 40 || !len)
 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 const char *ref_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
 248 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
 249 {
 250         const char **p, *r;
 251         int refs_found = 0;
 252
 253         *ref = NULL;
 254         for (p = ref_fmt; *p; p++) {
 255                 unsigned char sha1_from_ref[20];
 256                 unsigned char *this_result;
 257
 258                 this_result = refs_found ? sha1_from_ref : sha1;
 259                 r = resolve_ref(mkpath(*p, len, str), this_result, 1, NULL);
 260                 if (r) {
 261                         if (!refs_found++)
 262                                 *ref = xstrdup(r);
 263                         if (!warn_ambiguous_refs)
 264                                 break;
 265                 }
 266         }
 267         return refs_found;
 268 }
 269
 270 int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 271 {
 272         const char **p;
 273         int logs_found = 0;
 274
 275         *log = NULL;
 276         for (p = ref_fmt; *p; p++) {
 277                 struct stat st;
 278                 unsigned char hash[20];
 279                 char path[PATH_MAX];
 280                 const char *ref, *it;
 281
 282                 strcpy(path, mkpath(*p, len, str));
 283                 ref = resolve_ref(path, hash, 0, NULL);
 284                 if (!ref)
 285                         continue;
 286                 if (!stat(git_path("logs/%s", path), &st) &&
 287                     S_ISREG(st.st_mode))
 288                         it = path;
 289                 else if (strcmp(ref, path) &&
 290                          !stat(git_path("logs/%s", ref), &st) &&
 291                          S_ISREG(st.st_mode))
 292                         it = ref;
 293                 else
 294                         continue;
 295                 if (!logs_found++) {
 296                         *log = xstrdup(it);
 297                         hashcpy(sha1, hash);
 298                 }
 299                 if (!warn_ambiguous_refs)
 300                         break;
 301         }
 302         return logs_found;
 303 }
 304
 305 static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 306 {
 307         static const char *warning = "warning: refname '%.*s' is ambiguous.\n";
 308         char *real_ref = NULL;
 309         int refs_found = 0;
 310         int at, reflog_len;
 311
 312         if (len == 40 && !get_sha1_hex(str, sha1))
 313                 return 0;
 314
 315         /* basic@{time or number} format to query ref-log */
 316         reflog_len = at = 0;
 317         if (str[len-1] == '}') {
 318                 for (at = 0; at < len - 1; at++) {
 319                         if (str[at] == '@' && str[at+1] == '{') {
 320                                 reflog_len = (len-1) - (at+2);
 321                                 len = at;
 322                                 break;
 323                         }
 324                 }
 325         }
 326
 327         /* Accept only unambiguous ref paths. */
 328         if (len && ambiguous_path(str, len))
 329                 return -1;
 330
 331         if (!len && reflog_len) {
 332                 /* allow "@{...}" to mean the current branch reflog */
 333                 refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
 334         } else if (reflog_len)
 335                 refs_found = dwim_log(str, len, sha1, &real_ref);
 336         else
 337                 refs_found = dwim_ref(str, len, sha1, &real_ref);
 338
 339         if (!refs_found)
 340                 return -1;
 341
 342         if (warn_ambiguous_refs && refs_found > 1)
 343                 fprintf(stderr, warning, len, str);
 344
 345         if (reflog_len) {
 346                 int nth, i;
 347                 unsigned long at_time;
 348                 unsigned long co_time;
 349                 int co_tz, co_cnt;
 350
 351                 /* Is it asking for N-th entry, or approxidate? */
 352                 for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 353                         char ch = str[at+2+i];
 354                         if ('0' <= ch && ch <= '9')
 355                                 nth = nth * 10 + ch - '0';
 356                         else
 357                                 nth = -1;
 358                 }
 359                 if (0 <= nth)
 360                         at_time = 0;
 361                 else
 362                         at_time = approxidate(str + at + 2);
 363                 if (read_ref_at(real_ref, at_time, nth, sha1, NULL,
 364                                 &co_time, &co_tz, &co_cnt)) {
 365                         if (at_time)
 366                                 fprintf(stderr,
 367                                         "warning: Log for '%.*s' only goes "
 368                                         "back to %s.\n", len, str,
 369                                         show_rfc2822_date(co_time, co_tz));
 370                         else
 371                                 fprintf(stderr,
 372                                         "warning: Log for '%.*s' only has "
 373                                         "%d entries.\n", len, str, co_cnt);
 374                 }
 375         }
 376
 377         free(real_ref);
 378         return 0;
 379 }
 380
 381 static int get_sha1_1(const char *name, int len, unsigned char *sha1);
 382
 383 static int get_parent(const char *name, int len,
 384                       unsigned char *result, int idx)
 385 {
 386         unsigned char sha1[20];
 387         int ret = get_sha1_1(name, len, sha1);
 388         struct commit *commit;
 389         struct commit_list *p;
 390
 391         if (ret)
 392                 return ret;
 393         commit = lookup_commit_reference(sha1);
 394         if (!commit)
 395                 return -1;
 396         if (parse_commit(commit))
 397                 return -1;
 398         if (!idx) {
 399                 hashcpy(result, commit->object.sha1);
 400                 return 0;
 401         }
 402         p = commit->parents;
 403         while (p) {
 404                 if (!--idx) {
 405                         hashcpy(result, p->item->object.sha1);
 406                         return 0;
 407                 }
 408                 p = p->next;
 409         }
 410         return -1;
 411 }
 412
 413 static int get_nth_ancestor(const char *name, int len,
 414                             unsigned char *result, int generation)
 415 {
 416         unsigned char sha1[20];
 417         int ret = get_sha1_1(name, len, sha1);
 418         if (ret)
 419                 return ret;
 420
 421         while (generation--) {
 422                 struct commit *commit = lookup_commit_reference(sha1);
 423
 424                 if (!commit || parse_commit(commit) || !commit->parents)
 425                         return -1;
 426                 hashcpy(sha1, commit->parents->item->object.sha1);
 427         }
 428         hashcpy(result, sha1);
 429         return 0;
 430 }
 431
 432 static int peel_onion(const char *name, int len, unsigned char *sha1)
 433 {
 434         unsigned char outer[20];
 435         const char *sp;
 436         unsigned int expected_type = 0;
 437         struct object *o;
 438
 439         /*
 440          * "ref^{type}" dereferences ref repeatedly until you cannot
 441          * dereference anymore, or you get an object of given type,
 442          * whichever comes first.  "ref^{}" means just dereference
 443          * tags until you get a non-tag.  "ref^0" is a shorthand for
 444          * "ref^{commit}".  "commit^{tree}" could be used to find the
 445          * top-level tree of the given commit.
 446          */
 447         if (len < 4 || name[len-1] != '}')
 448                 return -1;
 449
 450         for (sp = name + len - 1; name <= sp; sp--) {
 451                 int ch = *sp;
 452                 if (ch == '{' && name < sp && sp[-1] == '^')
 453                         break;
 454         }
 455         if (sp <= name)
 456                 return -1;
 457
 458         sp++; /* beginning of type name, or closing brace for empty */
 459         if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
 460                 expected_type = OBJ_COMMIT;
 461         else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
 462                 expected_type = OBJ_TREE;
 463         else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
 464                 expected_type = OBJ_BLOB;
 465         else if (sp[0] == '}')
 466                 expected_type = OBJ_NONE;
 467         else
 468                 return -1;
 469
 470         if (get_sha1_1(name, sp - name - 2, outer))
 471                 return -1;
 472
 473         o = parse_object(outer);
 474         if (!o)
 475                 return -1;
 476         if (!expected_type) {
 477                 o = deref_tag(o, name, sp - name - 2);
 478                 if (!o || (!o->parsed && !parse_object(o->sha1)))
 479                         return -1;
 480                 hashcpy(sha1, o->sha1);
 481         }
 482         else {
 483                 /* At this point, the syntax look correct, so
 484                  * if we do not get the needed object, we should
 485                  * barf.
 486                  */
 487
 488                 while (1) {
 489                         if (!o || (!o->parsed && !parse_object(o->sha1)))
 490                                 return -1;
 491                         if (o->type == expected_type) {
 492                                 hashcpy(sha1, o->sha1);
 493                                 return 0;
 494                         }
 495                         if (o->type == OBJ_TAG)
 496                                 o = ((struct tag*) o)->tagged;
 497                         else if (o->type == OBJ_COMMIT)
 498                                 o = &(((struct commit *) o)->tree->object);
 499                         else
 500                                 return error("%.*s: expected %s type, but the object dereferences to %s type",
 501                                              len, name, typename(expected_type),
 502                                              typename(o->type));
 503                         if (!o->parsed)
 504                                 parse_object(o->sha1);
 505                 }
 506         }
 507         return 0;
 508 }
 509
 510 static int get_describe_name(const char *name, int len, unsigned char *sha1)
 511 {
 512         const char *cp;
 513
 514         for (cp = name + len - 1; name + 2 <= cp; cp--) {
 515                 char ch = *cp;
 516                 if (hexval(ch) & ~0377) {
 517                         /* We must be looking at g in "SOMETHING-g"
 518                          * for it to be describe output.
 519                          */
 520                         if (ch == 'g' && cp[-1] == '-') {
 521                                 cp++;
 522                                 len -= cp - name;
 523                                 return get_short_sha1(cp, len, sha1, 1);
 524                         }
 525                 }
 526         }
 527         return -1;
 528 }
 529
 530 static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 531 {
 532         int ret, has_suffix;
 533         const char *cp;
 534
 535         /* "name~3" is "name^^^",
 536          * "name~" and "name~0" are name -- not "name^0"!
 537          * "name^" is not "name^0"; it is "name^1".
 538          */
 539         has_suffix = 0;
 540         for (cp = name + len - 1; name <= cp; cp--) {
 541                 int ch = *cp;
 542                 if ('0' <= ch && ch <= '9')
 543                         continue;
 544                 if (ch == '~' || ch == '^')
 545                         has_suffix = ch;
 546                 break;
 547         }
 548
 549         if (has_suffix) {
 550                 int num = 0;
 551                 int len1 = cp - name;
 552                 cp++;
 553                 while (cp < name + len)
 554                         num = num * 10 + *cp++ - '0';
 555                 if (has_suffix == '^') {
 556                         if (!num && len1 == len - 1)
 557                                 num = 1;
 558                         return get_parent(name, len1, sha1, num);
 559                 }
 560                 /* else if (has_suffix == '~') -- goes without saying */
 561                 return get_nth_ancestor(name, len1, sha1, num);
 562         }
 563
 564         ret = peel_onion(name, len, sha1);
 565         if (!ret)
 566                 return 0;
 567
 568         ret = get_sha1_basic(name, len, sha1);
 569         if (!ret)
 570                 return 0;
 571
 572         /* It could be describe output that is "SOMETHING-gXXXX" */
 573         ret = get_describe_name(name, len, sha1);
 574         if (!ret)
 575                 return 0;
 576
 577         return get_short_sha1(name, len, sha1, 0);
 578 }
 579
 580 /*
 581  * This is like "get_sha1_basic()", except it allows "sha1 expressions",
 582  * notably "xyz^" for "parent of xyz"
 583  */
 584 int get_sha1(const char *name, unsigned char *sha1)
 585 {
 586         int ret, bracket_depth;
 587         unsigned unused;
 588         int namelen = strlen(name);
 589         const char *cp;
 590
 591         prepare_alt_odb();
 592         ret = get_sha1_1(name, namelen, sha1);
 593         if (!ret)
 594                 return ret;
 595         /* sha1:path --> object name of path in ent sha1
 596          * :path -> object name of path in index
 597          * :[0-3]:path -> object name of path in index at stage
 598          */
 599         if (name[0] == ':') {
 600                 int stage = 0;
 601                 struct cache_entry *ce;
 602                 int pos;
 603                 if (namelen < 3 ||
 604                     name[2] != ':' ||
 605                     name[1] < '0' || '3' < name[1])
 606                         cp = name + 1;
 607                 else {
 608                         stage = name[1] - '0';
 609                         cp = name + 3;
 610                 }
 611                 namelen = namelen - (cp - name);
 612                 if (!active_cache)
 613                         read_cache();
 614                 if (active_nr < 0)
 615                         return -1;
 616                 pos = cache_name_pos(cp, namelen);
 617                 if (pos < 0)
 618                         pos = -pos - 1;
 619                 while (pos < active_nr) {
 620                         ce = active_cache[pos];
 621                         if (ce_namelen(ce) != namelen ||
 622                             memcmp(ce->name, cp, namelen))
 623                                 break;
 624                         if (ce_stage(ce) == stage) {
 625                                 hashcpy(sha1, ce->sha1);
 626                                 return 0;
 627                         }
 628                         pos++;
 629                 }
 630                 return -1;
 631         }
 632         for (cp = name, bracket_depth = 0; *cp; cp++) {
 633                 if (*cp == '{')
 634                         bracket_depth++;
 635                 else if (bracket_depth && *cp == '}')
 636                         bracket_depth--;
 637                 else if (!bracket_depth && *cp == ':')
 638                         break;
 639         }
 640         if (*cp == ':') {
 641                 unsigned char tree_sha1[20];
 642                 if (!get_sha1_1(name, cp-name, tree_sha1))
 643                         return get_tree_entry(tree_sha1, cp+1, sha1,
 644                                               &unused);
 645         }
 646         return ret;
 647 }