src/revparse.c

   1 /*
   2  * Copyright (C) the libgit2 contributors. All rights reserved.
   3  *
   4  * This file is part of libgit2, distributed under the GNU GPL v2 with
   5  * a Linking Exception. For full terms see the included COPYING file.
   6  */
   7
   8 #include <assert.h>
   9
  10 #include "common.h"
  11 #include "buffer.h"
  12 #include "tree.h"
  13 #include "refdb.h"
  14
  15 #include "git2.h"
  16
  17 static int maybe_sha_or_abbrev(git_object** out, git_repository *repo, const char *spec, size_t speclen)
  18 {
  19         git_oid oid;
  20
  21         if (git_oid_fromstrn(&oid, spec, speclen) < 0)
  22                 return GIT_ENOTFOUND;
  23
  24         return git_object_lookup_prefix(out, repo, &oid, speclen, GIT_OBJ_ANY);
  25 }
  26
  27 static int maybe_sha(git_object** out, git_repository *repo, const char *spec)
  28 {
  29         size_t speclen = strlen(spec);
  30
  31         if (speclen != GIT_OID_HEXSZ)
  32                 return GIT_ENOTFOUND;
  33
  34         return maybe_sha_or_abbrev(out, repo, spec, speclen);
  35 }
  36
  37 static int maybe_abbrev(git_object** out, git_repository *repo, const char *spec)
  38 {
  39         size_t speclen = strlen(spec);
  40
  41         return maybe_sha_or_abbrev(out, repo, spec, speclen);
  42 }
  43
  44 static int build_regex(regex_t *regex, const char *pattern)
  45 {
  46         int error;
  47
  48         if (*pattern == '\0') {
  49                 giterr_set(GITERR_REGEX, "Empty pattern");
  50                 return GIT_EINVALIDSPEC;
  51         }
  52
  53         error = regcomp(regex, pattern, REG_EXTENDED);
  54         if (!error)
  55                 return 0;
  56
  57         error = giterr_set_regex(regex, error);
  58
  59         regfree(regex);
  60
  61         return error;
  62 }
  63
  64 static int maybe_describe(git_object**out, git_repository *repo, const char *spec)
  65 {
  66         const char *substr;
  67         int error;
  68         regex_t regex;
  69
  70         substr = strstr(spec, "-g");
  71
  72         if (substr == NULL)
  73                 return GIT_ENOTFOUND;
  74
  75         if (build_regex(&regex, ".+-[0-9]+-g[0-9a-fA-F]+") < 0)
  76                 return -1;
  77
  78         error = regexec(&regex, spec, 0, NULL, 0);
  79         regfree(&regex);
  80
  81         if (error)
  82                 return GIT_ENOTFOUND;
  83
  84         return maybe_abbrev(out, repo, substr+2);
  85 }
  86
  87 static int revparse_lookup_object(
  88         git_object **object_out,
  89         git_reference **reference_out,
  90         git_repository *repo,
  91         const char *spec)
  92 {
  93         int error;
  94         git_reference *ref;
  95
  96         if ((error = maybe_sha(object_out, repo, spec)) != GIT_ENOTFOUND)
  97                 return error;
  98
  99         error = git_reference_dwim(&ref, repo, spec);
 100         if (!error) {
 101
 102                 error = git_object_lookup(
 103                         object_out, repo, git_reference_target(ref), GIT_OBJ_ANY);
 104
 105                 if (!error)
 106                         *reference_out = ref;
 107
 108                 return error;
 109         }
 110
 111         if (error != GIT_ENOTFOUND)
 112                 return error;
 113
 114         if ((strlen(spec) < GIT_OID_HEXSZ) &&
 115                 ((error = maybe_abbrev(object_out, repo, spec)) != GIT_ENOTFOUND))
 116                         return error;
 117
 118         if ((error = maybe_describe(object_out, repo, spec)) != GIT_ENOTFOUND)
 119                 return error;
 120
 121         giterr_set(GITERR_REFERENCE, "Revspec '%s' not found.", spec);
 122         return GIT_ENOTFOUND;
 123 }
 124
 125 static int try_parse_numeric(int *n, const char *curly_braces_content)
 126 {
 127         int32_t content;
 128         const char *end_ptr;
 129
 130         if (git__strtol32(&content, curly_braces_content, &end_ptr, 10) < 0)
 131                 return -1;
 132
 133         if (*end_ptr != '\0')
 134                 return -1;
 135
 136         *n = (int)content;
 137         return 0;
 138 }
 139
 140 static int retrieve_previously_checked_out_branch_or_revision(git_object **out, git_reference **base_ref, git_repository *repo, const char *identifier, size_t position)
 141 {
 142         git_reference *ref = NULL;
 143         git_reflog *reflog = NULL;
 144         regex_t preg;
 145         int error = -1;
 146         size_t i, numentries, cur;
 147         const git_reflog_entry *entry;
 148         const char *msg;
 149         regmatch_t regexmatches[2];
 150         git_buf buf = GIT_BUF_INIT;
 151
 152         cur = position;
 153
 154         if (*identifier != '\0' || *base_ref != NULL)
 155                 return GIT_EINVALIDSPEC;
 156
 157         if (build_regex(&preg, "checkout: moving from (.*) to .*") < 0)
 158                 return -1;
 159
 160         if (git_reference_lookup(&ref, repo, GIT_HEAD_FILE) < 0)
 161                 goto cleanup;
 162
 163         if (git_reflog_read(&reflog, repo, GIT_HEAD_FILE) < 0)
 164                 goto cleanup;
 165
 166         numentries  = git_reflog_entrycount(reflog);
 167
 168         for (i = 0; i < numentries; i++) {
 169                 entry = git_reflog_entry_byindex(reflog, i);
 170                 msg = git_reflog_entry_message(entry);
 171                 if (!msg)
 172                         continue;
 173
 174                 if (regexec(&preg, msg, 2, regexmatches, 0))
 175                         continue;
 176
 177                 cur--;
 178
 179                 if (cur > 0)
 180                         continue;
 181
 182                 git_buf_put(&buf, msg+regexmatches[1].rm_so, regexmatches[1].rm_eo - regexmatches[1].rm_so);
 183
 184                 if ((error = git_reference_dwim(base_ref, repo, git_buf_cstr(&buf))) == 0)
 185                         goto cleanup;
 186
 187                 if (error < 0 && error != GIT_ENOTFOUND)
 188                         goto cleanup;
 189
 190                 error = maybe_abbrev(out, repo, git_buf_cstr(&buf));
 191
 192                 goto cleanup;
 193         }
 194
 195         error = GIT_ENOTFOUND;
 196
 197 cleanup:
 198         git_reference_free(ref);
 199         git_buf_free(&buf);
 200         regfree(&preg);
 201         git_reflog_free(reflog);
 202         return error;
 203 }
 204
 205 static int retrieve_oid_from_reflog(git_oid *oid, git_reference *ref, size_t identifier)
 206 {
 207         git_reflog *reflog;
 208         int error = -1;
 209         size_t numentries;
 210         const git_reflog_entry *entry;
 211         bool search_by_pos = (identifier <= 100000000);
 212
 213         if (git_reflog_read(&reflog, git_reference_owner(ref), git_reference_name(ref)) < 0)
 214                 return -1;
 215
 216         numentries = git_reflog_entrycount(reflog);
 217
 218         if (search_by_pos) {
 219                 if (numentries < identifier + 1) {
 220                         giterr_set(
 221                                 GITERR_REFERENCE,
 222                                 "Reflog for '%s' has only %"PRIuZ" entries, asked for %"PRIuZ,
 223                                 git_reference_name(ref), numentries, identifier);
 224
 225                         error = GIT_ENOTFOUND;
 226                         goto cleanup;
 227                 }
 228
 229                 entry = git_reflog_entry_byindex(reflog, identifier);
 230                 git_oid_cpy(oid, git_reflog_entry_id_new(entry));
 231                 error = 0;
 232                 goto cleanup;
 233
 234         } else {
 235                 size_t i;
 236                 git_time commit_time;
 237
 238                 for (i = 0; i < numentries; i++) {
 239                         entry = git_reflog_entry_byindex(reflog, i);
 240                         commit_time = git_reflog_entry_committer(entry)->when;
 241
 242                         if (commit_time.time > (git_time_t)identifier)
 243                                 continue;
 244
 245                         git_oid_cpy(oid, git_reflog_entry_id_new(entry));
 246                         error = 0;
 247                         goto cleanup;
 248                 }
 249
 250                 error = GIT_ENOTFOUND;
 251         }
 252
 253 cleanup:
 254         git_reflog_free(reflog);
 255         return error;
 256 }
 257
 258 static int retrieve_revobject_from_reflog(git_object **out, git_reference **base_ref, git_repository *repo, const char *identifier, size_t position)
 259 {
 260         git_reference *ref;
 261         git_oid oid;
 262         int error = -1;
 263
 264         if (*base_ref == NULL) {
 265                 if ((error = git_reference_dwim(&ref, repo, identifier)) < 0)
 266                         return error;
 267         } else {
 268                 ref = *base_ref;
 269                 *base_ref = NULL;
 270         }
 271
 272         if (position == 0) {
 273                 error = git_object_lookup(out, repo, git_reference_target(ref), GIT_OBJ_ANY);
 274                 goto cleanup;
 275         }
 276
 277         if ((error = retrieve_oid_from_reflog(&oid, ref, position)) < 0)
 278                 goto cleanup;
 279
 280         error = git_object_lookup(out, repo, &oid, GIT_OBJ_ANY);
 281
 282 cleanup:
 283         git_reference_free(ref);
 284         return error;
 285 }
 286
 287 static int retrieve_remote_tracking_reference(git_reference **base_ref, const char *identifier, git_repository *repo)
 288 {
 289         git_reference *tracking, *ref;
 290         int error = -1;
 291
 292         if (*base_ref == NULL) {
 293                 if ((error = git_reference_dwim(&ref, repo, identifier)) < 0)
 294                         return error;
 295         } else {
 296                 ref = *base_ref;
 297                 *base_ref = NULL;
 298         }
 299
 300         if (!git_reference_is_branch(ref)) {
 301                 error = GIT_EINVALIDSPEC;
 302                 goto cleanup;
 303         }
 304
 305         if ((error = git_branch_upstream(&tracking, ref)) < 0)
 306                 goto cleanup;
 307
 308         *base_ref = tracking;
 309
 310 cleanup:
 311         git_reference_free(ref);
 312         return error;
 313 }
 314
 315 static int handle_at_syntax(git_object **out, git_reference **ref, const char *spec, size_t identifier_len, git_repository* repo, const char *curly_braces_content)
 316 {
 317         bool is_numeric;
 318         int parsed = 0, error = -1;
 319         git_buf identifier = GIT_BUF_INIT;
 320         git_time_t timestamp;
 321
 322         assert(*out == NULL);
 323
 324         if (git_buf_put(&identifier, spec, identifier_len) < 0)
 325                 return -1;
 326
 327         is_numeric = !try_parse_numeric(&parsed, curly_braces_content);
 328
 329         if (*curly_braces_content == '-' && (!is_numeric || parsed == 0)) {
 330                 error = GIT_EINVALIDSPEC;
 331                 goto cleanup;
 332         }
 333
 334         if (is_numeric) {
 335                 if (parsed < 0)
 336                         error = retrieve_previously_checked_out_branch_or_revision(out, ref, repo, git_buf_cstr(&identifier), -parsed);
 337                 else
 338                         error = retrieve_revobject_from_reflog(out, ref, repo, git_buf_cstr(&identifier), parsed);
 339
 340                 goto cleanup;
 341         }
 342
 343         if (!strcmp(curly_braces_content, "u") || !strcmp(curly_braces_content, "upstream")) {
 344                 error = retrieve_remote_tracking_reference(ref, git_buf_cstr(&identifier), repo);
 345
 346                 goto cleanup;
 347         }
 348
 349         if (git__date_parse(&timestamp, curly_braces_content) < 0)
 350                 goto cleanup;
 351
 352         error = retrieve_revobject_from_reflog(out, ref, repo, git_buf_cstr(&identifier), (size_t)timestamp);
 353
 354 cleanup:
 355         git_buf_free(&identifier);
 356         return error;
 357 }
 358
 359 static git_otype parse_obj_type(const char *str)
 360 {
 361         if (!strcmp(str, "commit"))
 362                 return GIT_OBJ_COMMIT;
 363
 364         if (!strcmp(str, "tree"))
 365                 return GIT_OBJ_TREE;
 366
 367         if (!strcmp(str, "blob"))
 368                 return GIT_OBJ_BLOB;
 369
 370         if (!strcmp(str, "tag"))
 371                 return GIT_OBJ_TAG;
 372
 373         return GIT_OBJ_BAD;
 374 }
 375
 376 static int dereference_to_non_tag(git_object **out, git_object *obj)
 377 {
 378         if (git_object_type(obj) == GIT_OBJ_TAG)
 379                 return git_tag_peel(out, (git_tag *)obj);
 380
 381         return git_object_dup(out, obj);
 382 }
 383
 384 static int handle_caret_parent_syntax(git_object **out, git_object *obj, int n)
 385 {
 386         git_object *temp_commit = NULL;
 387         int error;
 388
 389         if ((error = git_object_peel(&temp_commit, obj, GIT_OBJ_COMMIT)) < 0)
 390                 return (error == GIT_EAMBIGUOUS || error == GIT_ENOTFOUND) ?
 391                         GIT_EINVALIDSPEC : error;
 392
 393         if (n == 0) {
 394                 *out = temp_commit;
 395                 return 0;
 396         }
 397
 398         error = git_commit_parent((git_commit **)out, (git_commit*)temp_commit, n - 1);
 399
 400         git_object_free(temp_commit);
 401         return error;
 402 }
 403
 404 static int handle_linear_syntax(git_object **out, git_object *obj, int n)
 405 {
 406         git_object *temp_commit = NULL;
 407         int error;
 408
 409         if ((error = git_object_peel(&temp_commit, obj, GIT_OBJ_COMMIT)) < 0)
 410                 return (error == GIT_EAMBIGUOUS || error == GIT_ENOTFOUND) ?
 411                         GIT_EINVALIDSPEC : error;
 412
 413         error = git_commit_nth_gen_ancestor((git_commit **)out, (git_commit*)temp_commit, n);
 414
 415         git_object_free(temp_commit);
 416         return error;
 417 }
 418
 419 static int handle_colon_syntax(
 420         git_object **out,
 421         git_object *obj,
 422         const char *path)
 423 {
 424         git_object *tree;
 425         int error = -1;
 426         git_tree_entry *entry = NULL;
 427
 428         if ((error = git_object_peel(&tree, obj, GIT_OBJ_TREE)) < 0)
 429                 return error == GIT_ENOTFOUND ? GIT_EINVALIDSPEC : error;
 430
 431         if (*path == '\0') {
 432                 *out = tree;
 433                 return 0;
 434         }
 435
 436         /*
 437          * TODO: Handle the relative path syntax
 438          * (:./relative/path and :../relative/path)
 439          */
 440         if ((error = git_tree_entry_bypath(&entry, (git_tree *)tree, path)) < 0)
 441                 goto cleanup;
 442
 443         error = git_tree_entry_to_object(out, git_object_owner(tree), entry);
 444
 445 cleanup:
 446         git_tree_entry_free(entry);
 447         git_object_free(tree);
 448
 449         return error;
 450 }
 451
 452 static int walk_and_search(git_object **out, git_revwalk *walk, regex_t *regex)
 453 {
 454         int error;
 455         git_oid oid;
 456         git_object *obj;
 457
 458         while (!(error = git_revwalk_next(&oid, walk))) {
 459
 460                 error = git_object_lookup(&obj, git_revwalk_repository(walk), &oid, GIT_OBJ_COMMIT);
 461                 if ((error < 0) && (error != GIT_ENOTFOUND))
 462                         return -1;
 463
 464                 if (!regexec(regex, git_commit_message((git_commit*)obj), 0, NULL, 0)) {
 465                         *out = obj;
 466                         return 0;
 467                 }
 468
 469                 git_object_free(obj);
 470         }
 471
 472         if (error < 0 && error == GIT_ITEROVER)
 473                 error = GIT_ENOTFOUND;
 474
 475         return error;
 476 }
 477
 478 static int handle_grep_syntax(git_object **out, git_repository *repo, const git_oid *spec_oid, const char *pattern)
 479 {
 480         regex_t preg;
 481         git_revwalk *walk = NULL;
 482         int error;
 483
 484         if ((error = build_regex(&preg, pattern)) < 0)
 485                 return error;
 486
 487         if ((error = git_revwalk_new(&walk, repo)) < 0)
 488                 goto cleanup;
 489
 490         git_revwalk_sorting(walk, GIT_SORT_TIME);
 491
 492         if (spec_oid == NULL) {
 493                 if ((error = git_revwalk_push_glob(walk, "refs/*")) < 0)
 494                         goto cleanup;
 495         } else if ((error = git_revwalk_push(walk, spec_oid)) < 0)
 496                         goto cleanup;
 497
 498         error = walk_and_search(out, walk, &preg);
 499
 500 cleanup:
 501         regfree(&preg);
 502         git_revwalk_free(walk);
 503
 504         return error;
 505 }
 506
 507 static int handle_caret_curly_syntax(git_object **out, git_object *obj, const char *curly_braces_content)
 508 {
 509         git_otype expected_type;
 510
 511         if (*curly_braces_content == '\0')
 512                 return dereference_to_non_tag(out, obj);
 513
 514         if (*curly_braces_content == '/')
 515                 return handle_grep_syntax(out, git_object_owner(obj), git_object_id(obj), curly_braces_content + 1);
 516
 517         expected_type = parse_obj_type(curly_braces_content);
 518
 519         if (expected_type == GIT_OBJ_BAD)
 520                 return GIT_EINVALIDSPEC;
 521
 522         return git_object_peel(out, obj, expected_type);
 523 }
 524
 525 static int extract_curly_braces_content(git_buf *buf, const char *spec, size_t *pos)
 526 {
 527         git_buf_clear(buf);
 528
 529         assert(spec[*pos] == '^' || spec[*pos] == '@');
 530
 531         (*pos)++;
 532
 533         if (spec[*pos] == '\0' || spec[*pos] != '{')
 534                 return GIT_EINVALIDSPEC;
 535
 536         (*pos)++;
 537
 538         while (spec[*pos] != '}') {
 539                 if (spec[*pos] == '\0')
 540                         return GIT_EINVALIDSPEC;
 541
 542                 git_buf_putc(buf, spec[(*pos)++]);
 543         }
 544
 545         (*pos)++;
 546
 547         return 0;
 548 }
 549
 550 static int extract_path(git_buf *buf, const char *spec, size_t *pos)
 551 {
 552         git_buf_clear(buf);
 553
 554         assert(spec[*pos] == ':');
 555
 556         (*pos)++;
 557
 558         if (git_buf_puts(buf, spec + *pos) < 0)
 559                 return -1;
 560
 561         *pos += git_buf_len(buf);
 562
 563         return 0;
 564 }
 565
 566 static int extract_how_many(int *n, const char *spec, size_t *pos)
 567 {
 568         const char *end_ptr;
 569         int parsed, accumulated;
 570         char kind = spec[*pos];
 571
 572         assert(spec[*pos] == '^' || spec[*pos] == '~');
 573
 574         accumulated = 0;
 575
 576         do {
 577                 do {
 578                         (*pos)++;
 579                         accumulated++;
 580                 } while (spec[(*pos)] == kind && kind == '~');
 581
 582                 if (git__isdigit(spec[*pos])) {
 583                         if (git__strtol32(&parsed, spec + *pos, &end_ptr, 10) < 0)
 584                                 return GIT_EINVALIDSPEC;
 585
 586                         accumulated += (parsed - 1);
 587                         *pos = end_ptr - spec;
 588                 }
 589
 590         }       while (spec[(*pos)] == kind && kind == '~');
 591
 592         *n = accumulated;
 593
 594         return 0;
 595 }
 596
 597 static int object_from_reference(git_object **object, git_reference *reference)
 598 {
 599         git_reference *resolved = NULL;
 600         int error;
 601
 602         if (git_reference_resolve(&resolved, reference) < 0)
 603                 return -1;
 604
 605         error = git_object_lookup(object, reference->db->repo, git_reference_target(resolved), GIT_OBJ_ANY);
 606         git_reference_free(resolved);
 607
 608         return error;
 609 }
 610
 611 static int ensure_base_rev_loaded(git_object **object, git_reference **reference, const char *spec, size_t identifier_len, git_repository *repo, bool allow_empty_identifier)
 612 {
 613         int error;
 614         git_buf identifier = GIT_BUF_INIT;
 615
 616         if (*object != NULL)
 617                 return 0;
 618
 619         if (*reference != NULL)
 620                 return object_from_reference(object, *reference);
 621
 622         if (!allow_empty_identifier && identifier_len == 0)
 623                 return GIT_EINVALIDSPEC;
 624
 625         if (git_buf_put(&identifier, spec, identifier_len) < 0)
 626                 return -1;
 627
 628         error = revparse_lookup_object(object, reference, repo, git_buf_cstr(&identifier));
 629         git_buf_free(&identifier);
 630
 631         return error;
 632 }
 633
 634 static int ensure_base_rev_is_not_known_yet(git_object *object)
 635 {
 636         if (object == NULL)
 637                 return 0;
 638
 639         return GIT_EINVALIDSPEC;
 640 }
 641
 642 static bool any_left_hand_identifier(git_object *object, git_reference *reference, size_t identifier_len)
 643 {
 644         if (object != NULL)
 645                 return true;
 646
 647         if (reference != NULL)
 648                 return true;
 649
 650         if (identifier_len > 0)
 651                 return true;
 652
 653         return false;
 654 }
 655
 656 static int ensure_left_hand_identifier_is_not_known_yet(git_object *object, git_reference *reference)
 657 {
 658         if (!ensure_base_rev_is_not_known_yet(object) && reference == NULL)
 659                 return 0;
 660
 661         return GIT_EINVALIDSPEC;
 662 }
 663
 664 int revparse__ext(
 665         git_object **object_out,
 666         git_reference **reference_out,
 667         size_t *identifier_len_out,
 668         git_repository *repo,
 669         const char *spec)
 670 {
 671         size_t pos = 0, identifier_len = 0;
 672         int error = -1, n;
 673         git_buf buf = GIT_BUF_INIT;
 674
 675         git_reference *reference = NULL;
 676         git_object *base_rev = NULL;
 677
 678         bool should_return_reference = true;
 679
 680         assert(object_out && reference_out && repo && spec);
 681
 682         *object_out = NULL;
 683         *reference_out = NULL;
 684
 685         while (spec[pos]) {
 686                 switch (spec[pos]) {
 687                 case '^':
 688                         should_return_reference = false;
 689
 690                         if ((error = ensure_base_rev_loaded(&base_rev, &reference, spec, identifier_len, repo, false)) < 0)
 691                                 goto cleanup;
 692
 693                         if (spec[pos+1] == '{') {
 694                                 git_object *temp_object = NULL;
 695
 696                                 if ((error = extract_curly_braces_content(&buf, spec, &pos)) < 0)
 697                                         goto cleanup;
 698
 699                                 if ((error = handle_caret_curly_syntax(&temp_object, base_rev, git_buf_cstr(&buf))) < 0)
 700                                         goto cleanup;
 701
 702                                 git_object_free(base_rev);
 703                                 base_rev = temp_object;
 704                         } else {
 705                                 git_object *temp_object = NULL;
 706
 707                                 if ((error = extract_how_many(&n, spec, &pos)) < 0)
 708                                         goto cleanup;
 709
 710                                 if ((error = handle_caret_parent_syntax(&temp_object, base_rev, n)) < 0)
 711                                         goto cleanup;
 712
 713                                 git_object_free(base_rev);
 714                                 base_rev = temp_object;
 715                         }
 716                         break;
 717
 718                 case '~':
 719                 {
 720                         git_object *temp_object = NULL;
 721
 722                         should_return_reference = false;
 723
 724                         if ((error = extract_how_many(&n, spec, &pos)) < 0)
 725                                 goto cleanup;
 726
 727                         if ((error = ensure_base_rev_loaded(&base_rev, &reference, spec, identifier_len, repo, false)) < 0)
 728                                 goto cleanup;
 729
 730                         if ((error = handle_linear_syntax(&temp_object, base_rev, n)) < 0)
 731                                 goto cleanup;
 732
 733                         git_object_free(base_rev);
 734                         base_rev = temp_object;
 735                         break;
 736                 }
 737
 738                 case ':':
 739                 {
 740                         git_object *temp_object = NULL;
 741
 742                         should_return_reference = false;
 743
 744                         if ((error = extract_path(&buf, spec, &pos)) < 0)
 745                                 goto cleanup;
 746
 747                         if (any_left_hand_identifier(base_rev, reference, identifier_len)) {
 748                                 if ((error = ensure_base_rev_loaded(&base_rev, &reference, spec, identifier_len, repo, true)) < 0)
 749                                         goto cleanup;
 750
 751                                 if ((error = handle_colon_syntax(&temp_object, base_rev, git_buf_cstr(&buf))) < 0)
 752                                         goto cleanup;
 753                         } else {
 754                                 if (*git_buf_cstr(&buf) == '/') {
 755                                         if ((error = handle_grep_syntax(&temp_object, repo, NULL, git_buf_cstr(&buf) + 1)) < 0)
 756                                                 goto cleanup;
 757                                 } else {
 758
 759                                         /*
 760                                          * TODO: support merge-stage path lookup (":2:Makefile")
 761                                          * and plain index blob lookup (:i-am/a/blob)
 762                                          */
 763                                         giterr_set(GITERR_INVALID, "Unimplemented");
 764                                         error = GIT_ERROR;
 765                                         goto cleanup;
 766                                 }
 767                         }
 768
 769                         git_object_free(base_rev);
 770                         base_rev = temp_object;
 771                         break;
 772                 }
 773
 774                 case '@':
 775                 {
 776                         if (spec[pos+1] == '{') {
 777                                 git_object *temp_object = NULL;
 778
 779                                 if ((error = extract_curly_braces_content(&buf, spec, &pos)) < 0)
 780                                         goto cleanup;
 781
 782                                 if ((error = ensure_base_rev_is_not_known_yet(base_rev)) < 0)
 783                                         goto cleanup;
 784
 785                                 if ((error = handle_at_syntax(&temp_object, &reference, spec, identifier_len, repo, git_buf_cstr(&buf))) < 0)
 786                                         goto cleanup;
 787
 788                                 if (temp_object != NULL)
 789                                         base_rev = temp_object;
 790                                 break;
 791                         } else {
 792                                 /* Fall through */
 793                         }
 794                 }
 795
 796                 default:
 797                         if ((error = ensure_left_hand_identifier_is_not_known_yet(base_rev, reference)) < 0)
 798                                 goto cleanup;
 799
 800                         pos++;
 801                         identifier_len++;
 802                 }
 803         }
 804
 805         if ((error = ensure_base_rev_loaded(&base_rev, &reference, spec, identifier_len, repo, false)) < 0)
 806                 goto cleanup;
 807
 808         if (!should_return_reference) {
 809                 git_reference_free(reference);
 810                 reference = NULL;
 811         }
 812
 813         *object_out = base_rev;
 814         *reference_out = reference;
 815         *identifier_len_out = identifier_len;
 816         error = 0;
 817
 818 cleanup:
 819         if (error) {
 820                 if (error == GIT_EINVALIDSPEC)
 821                         giterr_set(GITERR_INVALID,
 822                                 "Failed to parse revision specifier - Invalid pattern '%s'", spec);
 823
 824                 git_object_free(base_rev);
 825                 git_reference_free(reference);
 826         }
 827
 828         git_buf_free(&buf);
 829         return error;
 830 }
 831
 832 int git_revparse_ext(
 833         git_object **object_out,
 834         git_reference **reference_out,
 835         git_repository *repo,
 836         const char *spec)
 837 {
 838         int error;
 839         size_t identifier_len;
 840         git_object *obj = NULL;
 841         git_reference *ref = NULL;
 842
 843         if ((error = revparse__ext(&obj, &ref, &identifier_len, repo, spec)) < 0)
 844                 goto cleanup;
 845
 846         *object_out = obj;
 847         *reference_out = ref;
 848         GIT_UNUSED(identifier_len);
 849
 850         return 0;
 851
 852 cleanup:
 853         git_object_free(obj);
 854         git_reference_free(ref);
 855         return error;
 856 }
 857
 858 int git_revparse_single(git_object **out, git_repository *repo, const char *spec)
 859 {
 860         int error;
 861         git_object *obj = NULL;
 862         git_reference *ref = NULL;
 863
 864         *out = NULL;
 865
 866         if ((error = git_revparse_ext(&obj, &ref, repo, spec)) < 0)
 867                 goto cleanup;
 868
 869         git_reference_free(ref);
 870
 871         *out = obj;
 872
 873         return 0;
 874
 875 cleanup:
 876         git_object_free(obj);
 877         git_reference_free(ref);
 878         return error;
 879 }
 880
 881 int git_revparse(
 882         git_revspec *revspec,
 883         git_repository *repo,
 884         const char *spec)
 885 {
 886         const char *dotdot;
 887         int error = 0;
 888
 889         assert(revspec && repo && spec);
 890
 891         memset(revspec, 0x0, sizeof(*revspec));
 892
 893         if ((dotdot = strstr(spec, "..")) != NULL) {
 894                 char *lstr;
 895                 const char *rstr;
 896                 revspec->flags = GIT_REVPARSE_RANGE;
 897
 898                 lstr = git__substrdup(spec, dotdot - spec);
 899                 rstr = dotdot + 2;
 900                 if (dotdot[2] == '.') {
 901                         revspec->flags |= GIT_REVPARSE_MERGE_BASE;
 902                         rstr++;
 903                 }
 904
 905                 error = git_revparse_single(&revspec->from, repo, lstr);
 906                 if (!error)
 907                         error = git_revparse_single(&revspec->to, repo, rstr);
 908
 909                 git__free((void*)lstr);
 910         } else {
 911                 revspec->flags = GIT_REVPARSE_SINGLE;
 912                 error = git_revparse_single(&revspec->from, repo, spec);
 913         }
 914
 915         return error;
 916 }