Andrew's git / gitweb.git / sha1_name.c
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sha1_name.con commit Make git-branch a builtin (c31820c)
   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
   9static 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
  56static 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
  71static 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
 130static 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
 153static 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        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
 189const 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
 213static 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
 238static 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, *ref;
 251        char *real_ref = 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                        strlcpy(date_spec, str + am + 2, date_len + 1);
 266                        at_time = approxidate(date_spec);
 267                        free(date_spec);
 268                        len = am;
 269                        break;
 270                }
 271        }
 272
 273        /* Accept only unambiguous ref paths. */
 274        if (ambiguous_path(str, len))
 275                return -1;
 276
 277        for (p = fmt; *p; p++) {
 278                this_result = refs_found ? sha1_from_ref : sha1;
 279                ref = resolve_ref(mkpath(*p, len, str), this_result, 1, NULL);
 280                if (ref) {
 281                        if (!refs_found++)
 282                                real_ref = xstrdup(ref);
 283                        if (!warn_ambiguous_refs)
 284                                break;
 285                }
 286        }
 287
 288        if (!refs_found)
 289                return -1;
 290
 291        if (warn_ambiguous_refs && refs_found > 1)
 292                fprintf(stderr, warning, len, str);
 293
 294        if (at_time != (unsigned long)-1) {
 295                read_ref_at(
 296                        real_ref,
 297                        at_time,
 298                        sha1);
 299        }
 300
 301        free(real_ref);
 302        return 0;
 303}
 304
 305static int get_sha1_1(const char *name, int len, unsigned char *sha1);
 306
 307static int get_parent(const char *name, int len,
 308                      unsigned char *result, int idx)
 309{
 310        unsigned char sha1[20];
 311        int ret = get_sha1_1(name, len, sha1);
 312        struct commit *commit;
 313        struct commit_list *p;
 314
 315        if (ret)
 316                return ret;
 317        commit = lookup_commit_reference(sha1);
 318        if (!commit)
 319                return -1;
 320        if (parse_commit(commit))
 321                return -1;
 322        if (!idx) {
 323                hashcpy(result, commit->object.sha1);
 324                return 0;
 325        }
 326        p = commit->parents;
 327        while (p) {
 328                if (!--idx) {
 329                        hashcpy(result, p->item->object.sha1);
 330                        return 0;
 331                }
 332                p = p->next;
 333        }
 334        return -1;
 335}
 336
 337static int get_nth_ancestor(const char *name, int len,
 338                            unsigned char *result, int generation)
 339{
 340        unsigned char sha1[20];
 341        int ret = get_sha1_1(name, len, sha1);
 342        if (ret)
 343                return ret;
 344
 345        while (generation--) {
 346                struct commit *commit = lookup_commit_reference(sha1);
 347
 348                if (!commit || parse_commit(commit) || !commit->parents)
 349                        return -1;
 350                hashcpy(sha1, commit->parents->item->object.sha1);
 351        }
 352        hashcpy(result, sha1);
 353        return 0;
 354}
 355
 356static int peel_onion(const char *name, int len, unsigned char *sha1)
 357{
 358        unsigned char outer[20];
 359        const char *sp;
 360        unsigned int expected_type = 0;
 361        struct object *o;
 362
 363        /*
 364         * "ref^{type}" dereferences ref repeatedly until you cannot
 365         * dereference anymore, or you get an object of given type,
 366         * whichever comes first.  "ref^{}" means just dereference
 367         * tags until you get a non-tag.  "ref^0" is a shorthand for
 368         * "ref^{commit}".  "commit^{tree}" could be used to find the
 369         * top-level tree of the given commit.
 370         */
 371        if (len < 4 || name[len-1] != '}')
 372                return -1;
 373
 374        for (sp = name + len - 1; name <= sp; sp--) {
 375                int ch = *sp;
 376                if (ch == '{' && name < sp && sp[-1] == '^')
 377                        break;
 378        }
 379        if (sp <= name)
 380                return -1;
 381
 382        sp++; /* beginning of type name, or closing brace for empty */
 383        if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
 384                expected_type = OBJ_COMMIT;
 385        else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
 386                expected_type = OBJ_TREE;
 387        else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
 388                expected_type = OBJ_BLOB;
 389        else if (sp[0] == '}')
 390                expected_type = OBJ_NONE;
 391        else
 392                return -1;
 393
 394        if (get_sha1_1(name, sp - name - 2, outer))
 395                return -1;
 396
 397        o = parse_object(outer);
 398        if (!o)
 399                return -1;
 400        if (!expected_type) {
 401                o = deref_tag(o, name, sp - name - 2);
 402                if (!o || (!o->parsed && !parse_object(o->sha1)))
 403                        return -1;
 404                hashcpy(sha1, o->sha1);
 405        }
 406        else {
 407                /* At this point, the syntax look correct, so
 408                 * if we do not get the needed object, we should
 409                 * barf.
 410                 */
 411
 412                while (1) {
 413                        if (!o || (!o->parsed && !parse_object(o->sha1)))
 414                                return -1;
 415                        if (o->type == expected_type) {
 416                                hashcpy(sha1, o->sha1);
 417                                return 0;
 418                        }
 419                        if (o->type == OBJ_TAG)
 420                                o = ((struct tag*) o)->tagged;
 421                        else if (o->type == OBJ_COMMIT)
 422                                o = &(((struct commit *) o)->tree->object);
 423                        else
 424                                return error("%.*s: expected %s type, but the object dereferences to %s type",
 425                                             len, name, typename(expected_type),
 426                                             typename(o->type));
 427                        if (!o->parsed)
 428                                parse_object(o->sha1);
 429                }
 430        }
 431        return 0;
 432}
 433
 434static int get_describe_name(const char *name, int len, unsigned char *sha1)
 435{
 436        const char *cp;
 437
 438        for (cp = name + len - 1; name + 2 <= cp; cp--) {
 439                char ch = *cp;
 440                if (hexval(ch) & ~0377) {
 441                        /* We must be looking at g in "SOMETHING-g"
 442                         * for it to be describe output.
 443                         */
 444                        if (ch == 'g' && cp[-1] == '-') {
 445                                cp++;
 446                                len -= cp - name;
 447                                return get_short_sha1(cp, len, sha1, 1);
 448                        }
 449                }
 450        }
 451        return -1;
 452}
 453
 454static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 455{
 456        int ret, has_suffix;
 457        const char *cp;
 458
 459        /* "name~3" is "name^^^",
 460         * "name~" and "name~0" are name -- not "name^0"!
 461         * "name^" is not "name^0"; it is "name^1".
 462         */
 463        has_suffix = 0;
 464        for (cp = name + len - 1; name <= cp; cp--) {
 465                int ch = *cp;
 466                if ('0' <= ch && ch <= '9')
 467                        continue;
 468                if (ch == '~' || ch == '^')
 469                        has_suffix = ch;
 470                break;
 471        }
 472
 473        if (has_suffix) {
 474                int num = 0;
 475                int len1 = cp - name;
 476                cp++;
 477                while (cp < name + len)
 478                        num = num * 10 + *cp++ - '0';
 479                if (has_suffix == '^') {
 480                        if (!num && len1 == len - 1)
 481                                num = 1;
 482                        return get_parent(name, len1, sha1, num);
 483                }
 484                /* else if (has_suffix == '~') -- goes without saying */
 485                return get_nth_ancestor(name, len1, sha1, num);
 486        }
 487
 488        ret = peel_onion(name, len, sha1);
 489        if (!ret)
 490                return 0;
 491
 492        ret = get_sha1_basic(name, len, sha1);
 493        if (!ret)
 494                return 0;
 495
 496        /* It could be describe output that is "SOMETHING-gXXXX" */
 497        ret = get_describe_name(name, len, sha1);
 498        if (!ret)
 499                return 0;
 500
 501        return get_short_sha1(name, len, sha1, 0);
 502}
 503
 504/*
 505 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
 506 * notably "xyz^" for "parent of xyz"
 507 */
 508int get_sha1(const char *name, unsigned char *sha1)
 509{
 510        int ret, bracket_depth;
 511        unsigned unused;
 512        int namelen = strlen(name);
 513        const char *cp;
 514
 515        prepare_alt_odb();
 516        ret = get_sha1_1(name, namelen, sha1);
 517        if (!ret)
 518                return ret;
 519        /* sha1:path --> object name of path in ent sha1
 520         * :path -> object name of path in index
 521         * :[0-3]:path -> object name of path in index at stage
 522         */
 523        if (name[0] == ':') {
 524                int stage = 0;
 525                struct cache_entry *ce;
 526                int pos;
 527                if (namelen < 3 ||
 528                    name[2] != ':' ||
 529                    name[1] < '0' || '3' < name[1])
 530                        cp = name + 1;
 531                else {
 532                        stage = name[1] - '0';
 533                        cp = name + 3;
 534                }
 535                namelen = namelen - (cp - name);
 536                if (!active_cache)
 537                        read_cache();
 538                if (active_nr < 0)
 539                        return -1;
 540                pos = cache_name_pos(cp, namelen);
 541                if (pos < 0)
 542                        pos = -pos - 1;
 543                while (pos < active_nr) {
 544                        ce = active_cache[pos];
 545                        if (ce_namelen(ce) != namelen ||
 546                            memcmp(ce->name, cp, namelen))
 547                                break;
 548                        if (ce_stage(ce) == stage) {
 549                                hashcpy(sha1, ce->sha1);
 550                                return 0;
 551                        }
 552                        pos++;
 553                }
 554                return -1;
 555        }
 556        for (cp = name, bracket_depth = 0; *cp; cp++) {
 557                if (*cp == '{')
 558                        bracket_depth++;
 559                else if (bracket_depth && *cp == '}')
 560                        bracket_depth--;
 561                else if (!bracket_depth && *cp == ':')
 562                        break;
 563        }
 564        if (*cp == ':') {
 565                unsigned char tree_sha1[20];
 566                if (!get_sha1_1(name, cp-name, tree_sha1))
 567                        return get_tree_entry(tree_sha1, cp+1, sha1,
 568                                              &unused);
 569        }
 570        return ret;
 571}