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 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
 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         const char **p, *r;
 250         int refs_found = 0;
 251
 252         *ref = NULL;
 253         for (p = fmt; *p; p++) {
 254                 unsigned char sha1_from_ref[20];
 255                 unsigned char *this_result;
 256
 257                 this_result = refs_found ? sha1_from_ref : sha1;
 258                 r = resolve_ref(mkpath(*p, len, str), this_result, 1, NULL);
 259                 if (r) {
 260                         if (!refs_found++)
 261                                 *ref = xstrdup(r);
 262                         if (!warn_ambiguous_refs)
 263                                 break;
 264                 }
 265         }
 266         return refs_found;
 267 }
 268
 269 static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 270 {
 271         static const char *warning = "warning: refname '%.*s' is ambiguous.\n";
 272         char *real_ref = NULL;
 273         int refs_found = 0;
 274         int at, reflog_len;
 275
 276         if (len == 40 && !get_sha1_hex(str, sha1))
 277                 return 0;
 278
 279         /* basic@{time or number} format to query ref-log */
 280         reflog_len = at = 0;
 281         if (str[len-1] == '}') {
 282                 for (at = 0; at < len - 1; at++) {
 283                         if (str[at] == '@' && str[at+1] == '{') {
 284                                 reflog_len = (len-1) - (at+2);
 285                                 len = at;
 286                                 break;
 287                         }
 288                 }
 289         }
 290
 291         /* Accept only unambiguous ref paths. */
 292         if (len && ambiguous_path(str, len))
 293                 return -1;
 294
 295         if (!len && reflog_len) {
 296                 /* allow "@{...}" to mean the current branch reflog */
 297                 refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
 298         } else
 299                 refs_found = dwim_ref(str, len, sha1, &real_ref);
 300
 301         if (!refs_found)
 302                 return -1;
 303
 304         if (warn_ambiguous_refs && refs_found > 1)
 305                 fprintf(stderr, warning, len, str);
 306
 307         if (reflog_len) {
 308                 int nth, i;
 309                 unsigned long at_time;
 310                 unsigned long co_time;
 311                 int co_tz, co_cnt;
 312
 313                 /*
 314                  * We'll have an independent reflog for "HEAD" eventually
 315                  * which won't be a synonym for the current branch reflog.
 316                  * In the mean time prevent people from getting used to
 317                  * such a synonym until the work is completed.
 318                  */
 319                 if (len && !strncmp("HEAD", str, len) &&
 320                     !strncmp(real_ref, "refs/", 5)) {
 321                         error("reflog for HEAD has not been implemented yet\n"
 322                               "Maybe you could try %s%s instead, "
 323                               "or just %s for current branch..",
 324                               strchr(real_ref+5, '/')+1, str+len, str+len);
 325                         exit(-1);
 326                 }
 327
 328                 /* Is it asking for N-th entry, or approxidate? */
 329                 for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 330                         char ch = str[at+2+i];
 331                         if ('0' <= ch && ch <= '9')
 332                                 nth = nth * 10 + ch - '0';
 333                         else
 334                                 nth = -1;
 335                 }
 336                 if (0 <= nth)
 337                         at_time = 0;
 338                 else
 339                         at_time = approxidate(str + at + 2);
 340                 if (read_ref_at(real_ref, at_time, nth, sha1, NULL,
 341                                 &co_time, &co_tz, &co_cnt)) {
 342                         if (at_time)
 343                                 fprintf(stderr,
 344                                         "warning: Log for '%.*s' only goes "
 345                                         "back to %s.\n", len, str,
 346                                         show_rfc2822_date(co_time, co_tz));
 347                         else
 348                                 fprintf(stderr,
 349                                         "warning: Log for '%.*s' only has "
 350                                         "%d entries.\n", len, str, co_cnt);
 351                 }
 352         }
 353
 354         free(real_ref);
 355         return 0;
 356 }
 357
 358 static int get_sha1_1(const char *name, int len, unsigned char *sha1);
 359
 360 static int get_parent(const char *name, int len,
 361                       unsigned char *result, int idx)
 362 {
 363         unsigned char sha1[20];
 364         int ret = get_sha1_1(name, len, sha1);
 365         struct commit *commit;
 366         struct commit_list *p;
 367
 368         if (ret)
 369                 return ret;
 370         commit = lookup_commit_reference(sha1);
 371         if (!commit)
 372                 return -1;
 373         if (parse_commit(commit))
 374                 return -1;
 375         if (!idx) {
 376                 hashcpy(result, commit->object.sha1);
 377                 return 0;
 378         }
 379         p = commit->parents;
 380         while (p) {
 381                 if (!--idx) {
 382                         hashcpy(result, p->item->object.sha1);
 383                         return 0;
 384                 }
 385                 p = p->next;
 386         }
 387         return -1;
 388 }
 389
 390 static int get_nth_ancestor(const char *name, int len,
 391                             unsigned char *result, int generation)
 392 {
 393         unsigned char sha1[20];
 394         int ret = get_sha1_1(name, len, sha1);
 395         if (ret)
 396                 return ret;
 397
 398         while (generation--) {
 399                 struct commit *commit = lookup_commit_reference(sha1);
 400
 401                 if (!commit || parse_commit(commit) || !commit->parents)
 402                         return -1;
 403                 hashcpy(sha1, commit->parents->item->object.sha1);
 404         }
 405         hashcpy(result, sha1);
 406         return 0;
 407 }
 408
 409 static int peel_onion(const char *name, int len, unsigned char *sha1)
 410 {
 411         unsigned char outer[20];
 412         const char *sp;
 413         unsigned int expected_type = 0;
 414         struct object *o;
 415
 416         /*
 417          * "ref^{type}" dereferences ref repeatedly until you cannot
 418          * dereference anymore, or you get an object of given type,
 419          * whichever comes first.  "ref^{}" means just dereference
 420          * tags until you get a non-tag.  "ref^0" is a shorthand for
 421          * "ref^{commit}".  "commit^{tree}" could be used to find the
 422          * top-level tree of the given commit.
 423          */
 424         if (len < 4 || name[len-1] != '}')
 425                 return -1;
 426
 427         for (sp = name + len - 1; name <= sp; sp--) {
 428                 int ch = *sp;
 429                 if (ch == '{' && name < sp && sp[-1] == '^')
 430                         break;
 431         }
 432         if (sp <= name)
 433                 return -1;
 434
 435         sp++; /* beginning of type name, or closing brace for empty */
 436         if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
 437                 expected_type = OBJ_COMMIT;
 438         else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
 439                 expected_type = OBJ_TREE;
 440         else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
 441                 expected_type = OBJ_BLOB;
 442         else if (sp[0] == '}')
 443                 expected_type = OBJ_NONE;
 444         else
 445                 return -1;
 446
 447         if (get_sha1_1(name, sp - name - 2, outer))
 448                 return -1;
 449
 450         o = parse_object(outer);
 451         if (!o)
 452                 return -1;
 453         if (!expected_type) {
 454                 o = deref_tag(o, name, sp - name - 2);
 455                 if (!o || (!o->parsed && !parse_object(o->sha1)))
 456                         return -1;
 457                 hashcpy(sha1, o->sha1);
 458         }
 459         else {
 460                 /* At this point, the syntax look correct, so
 461                  * if we do not get the needed object, we should
 462                  * barf.
 463                  */
 464
 465                 while (1) {
 466                         if (!o || (!o->parsed && !parse_object(o->sha1)))
 467                                 return -1;
 468                         if (o->type == expected_type) {
 469                                 hashcpy(sha1, o->sha1);
 470                                 return 0;
 471                         }
 472                         if (o->type == OBJ_TAG)
 473                                 o = ((struct tag*) o)->tagged;
 474                         else if (o->type == OBJ_COMMIT)
 475                                 o = &(((struct commit *) o)->tree->object);
 476                         else
 477                                 return error("%.*s: expected %s type, but the object dereferences to %s type",
 478                                              len, name, typename(expected_type),
 479                                              typename(o->type));
 480                         if (!o->parsed)
 481                                 parse_object(o->sha1);
 482                 }
 483         }
 484         return 0;
 485 }
 486
 487 static int get_describe_name(const char *name, int len, unsigned char *sha1)
 488 {
 489         const char *cp;
 490
 491         for (cp = name + len - 1; name + 2 <= cp; cp--) {
 492                 char ch = *cp;
 493                 if (hexval(ch) & ~0377) {
 494                         /* We must be looking at g in "SOMETHING-g"
 495                          * for it to be describe output.
 496                          */
 497                         if (ch == 'g' && cp[-1] == '-') {
 498                                 cp++;
 499                                 len -= cp - name;
 500                                 return get_short_sha1(cp, len, sha1, 1);
 501                         }
 502                 }
 503         }
 504         return -1;
 505 }
 506
 507 static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 508 {
 509         int ret, has_suffix;
 510         const char *cp;
 511
 512         /* "name~3" is "name^^^",
 513          * "name~" and "name~0" are name -- not "name^0"!
 514          * "name^" is not "name^0"; it is "name^1".
 515          */
 516         has_suffix = 0;
 517         for (cp = name + len - 1; name <= cp; cp--) {
 518                 int ch = *cp;
 519                 if ('0' <= ch && ch <= '9')
 520                         continue;
 521                 if (ch == '~' || ch == '^')
 522                         has_suffix = ch;
 523                 break;
 524         }
 525
 526         if (has_suffix) {
 527                 int num = 0;
 528                 int len1 = cp - name;
 529                 cp++;
 530                 while (cp < name + len)
 531                         num = num * 10 + *cp++ - '0';
 532                 if (has_suffix == '^') {
 533                         if (!num && len1 == len - 1)
 534                                 num = 1;
 535                         return get_parent(name, len1, sha1, num);
 536                 }
 537                 /* else if (has_suffix == '~') -- goes without saying */
 538                 return get_nth_ancestor(name, len1, sha1, num);
 539         }
 540
 541         ret = peel_onion(name, len, sha1);
 542         if (!ret)
 543                 return 0;
 544
 545         ret = get_sha1_basic(name, len, sha1);
 546         if (!ret)
 547                 return 0;
 548
 549         /* It could be describe output that is "SOMETHING-gXXXX" */
 550         ret = get_describe_name(name, len, sha1);
 551         if (!ret)
 552                 return 0;
 553
 554         return get_short_sha1(name, len, sha1, 0);
 555 }
 556
 557 /*
 558  * This is like "get_sha1_basic()", except it allows "sha1 expressions",
 559  * notably "xyz^" for "parent of xyz"
 560  */
 561 int get_sha1(const char *name, unsigned char *sha1)
 562 {
 563         int ret, bracket_depth;
 564         unsigned unused;
 565         int namelen = strlen(name);
 566         const char *cp;
 567
 568         prepare_alt_odb();
 569         ret = get_sha1_1(name, namelen, sha1);
 570         if (!ret)
 571                 return ret;
 572         /* sha1:path --> object name of path in ent sha1
 573          * :path -> object name of path in index
 574          * :[0-3]:path -> object name of path in index at stage
 575          */
 576         if (name[0] == ':') {
 577                 int stage = 0;
 578                 struct cache_entry *ce;
 579                 int pos;
 580                 if (namelen < 3 ||
 581                     name[2] != ':' ||
 582                     name[1] < '0' || '3' < name[1])
 583                         cp = name + 1;
 584                 else {
 585                         stage = name[1] - '0';
 586                         cp = name + 3;
 587                 }
 588                 namelen = namelen - (cp - name);
 589                 if (!active_cache)
 590                         read_cache();
 591                 if (active_nr < 0)
 592                         return -1;
 593                 pos = cache_name_pos(cp, namelen);
 594                 if (pos < 0)
 595                         pos = -pos - 1;
 596                 while (pos < active_nr) {
 597                         ce = active_cache[pos];
 598                         if (ce_namelen(ce) != namelen ||
 599                             memcmp(ce->name, cp, namelen))
 600                                 break;
 601                         if (ce_stage(ce) == stage) {
 602                                 hashcpy(sha1, ce->sha1);
 603                                 return 0;
 604                         }
 605                         pos++;
 606                 }
 607                 return -1;
 608         }
 609         for (cp = name, bracket_depth = 0; *cp; cp++) {
 610                 if (*cp == '{')
 611                         bracket_depth++;
 612                 else if (bracket_depth && *cp == '}')
 613                         bracket_depth--;
 614                 else if (!bracket_depth && *cp == ':')
 615                         break;
 616         }
 617         if (*cp == ':') {
 618                 unsigned char tree_sha1[20];
 619                 if (!get_sha1_1(name, cp-name, tree_sha1))
 620                         return get_tree_entry(tree_sha1, cp+1, sha1,
 621                                               &unused);
 622         }
 623         return ret;
 624 }