Andrew's git - gitweb.git/blob

   1#include "cache.h"
   2#include "tag.h"
   3#include "commit.h"
   4#include "tree.h"
   5#include "blob.h"
   6
   7static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
   8{
   9        struct alternate_object_database *alt;
  10        char hex[40];
  11        int found = 0;
  12        static struct alternate_object_database *fakeent;
  13
  14        if (!fakeent) {
  15                const char *objdir = get_object_directory();
  16                int objdir_len = strlen(objdir);
  17                int entlen = objdir_len + 43;
  18                fakeent = xmalloc(sizeof(*fakeent) + entlen);
  19                memcpy(fakeent->base, objdir, objdir_len);
  20                fakeent->name = fakeent->base + objdir_len + 1;
  21                fakeent->name[-1] = '/';
  22        }
  23        fakeent->next = alt_odb_list;
  24
  25        sprintf(hex, "%.2s", name);
  26        for (alt = fakeent; alt && found < 2; alt = alt->next) {
  27                struct dirent *de;
  28                DIR *dir;
  29                sprintf(alt->name, "%.2s/", name);
  30                dir = opendir(alt->base);
  31                if (!dir)
  32                        continue;
  33                while ((de = readdir(dir)) != NULL) {
  34                        if (strlen(de->d_name) != 38)
  35                                continue;
  36                        if (memcmp(de->d_name, name + 2, len - 2))
  37                                continue;
  38                        if (!found) {
  39                                memcpy(hex + 2, de->d_name, 38);
  40                                found++;
  41                        }
  42                        else if (memcmp(hex + 2, de->d_name, 38)) {
  43                                found = 2;
  44                                break;
  45                        }
  46                }
  47                closedir(dir);
  48        }
  49        if (found == 1)
  50                return get_sha1_hex(hex, sha1) == 0;
  51        return found;
  52}
  53
  54static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
  55{
  56        do {
  57                if (*a != *b)
  58                        return 0;
  59                a++;
  60                b++;
  61                len -= 2;
  62        } while (len > 1);
  63        if (len)
  64                if ((*a ^ *b) & 0xf0)
  65                        return 0;
  66        return 1;
  67}
  68
  69static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
  70{
  71        struct packed_git *p;
  72        unsigned char found_sha1[20];
  73        int found = 0;
  74
  75        prepare_packed_git();
  76        for (p = packed_git; p && found < 2; p = p->next) {
  77                unsigned num = num_packed_objects(p);
  78                unsigned first = 0, last = num;
  79                while (first < last) {
  80                        unsigned mid = (first + last) / 2;
  81                        unsigned char now[20];
  82                        int cmp;
  83
  84                        nth_packed_object_sha1(p, mid, now);
  85                        cmp = memcmp(match, now, 20);
  86                        if (!cmp) {
  87                                first = mid;
  88                                break;
  89                        }
  90                        if (cmp > 0) {
  91                                first = mid+1;
  92                                continue;
  93                        }
  94                        last = mid;
  95                }
  96                if (first < num) {
  97                        unsigned char now[20], next[20];
  98                        nth_packed_object_sha1(p, first, now);
  99                        if (match_sha(len, match, now)) {
 100                                if (nth_packed_object_sha1(p, first+1, next) ||
 101                                    !match_sha(len, match, next)) {
 102                                        /* unique within this pack */
 103                                        if (!found) {
 104                                                memcpy(found_sha1, now, 20);
 105                                                found++;
 106                                        }
 107                                        else if (memcmp(found_sha1, now, 20)) {
 108                                                found = 2;
 109                                                break;
 110                                        }
 111                                }
 112                                else {
 113                                        /* not even unique within this pack */
 114                                        found = 2;
 115                                        break;
 116                                }
 117                        }
 118                }
 119        }
 120        if (found == 1)
 121                memcpy(sha1, found_sha1, 20);
 122        return found;
 123}
 124
 125#define SHORT_NAME_NOT_FOUND (-1)
 126#define SHORT_NAME_AMBIGUOUS (-2)
 127
 128static int find_unique_short_object(int len, char *canonical,
 129                                    unsigned char *res, unsigned char *sha1)
 130{
 131        int has_unpacked, has_packed;
 132        unsigned char unpacked_sha1[20], packed_sha1[20];
 133
 134        has_unpacked = find_short_object_filename(len, canonical, unpacked_sha1);
 135        has_packed = find_short_packed_object(len, res, packed_sha1);
 136        if (!has_unpacked && !has_packed)
 137                return SHORT_NAME_NOT_FOUND;
 138        if (1 < has_unpacked || 1 < has_packed)
 139                return SHORT_NAME_AMBIGUOUS;
 140        if (has_unpacked != has_packed) {
 141                memcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1), 20);
 142                return 0;
 143        }
 144        /* Both have unique ones -- do they match? */
 145        if (memcmp(packed_sha1, unpacked_sha1, 20))
 146                return -2;
 147        memcpy(sha1, packed_sha1, 20);
 148        return 0;
 149}
 150
 151static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 152                          int quietly)
 153{
 154        int i, status;
 155        char canonical[40];
 156        unsigned char res[20];
 157
 158        if (len < 4)
 159                return -1;
 160        memset(res, 0, 20);
 161        memset(canonical, 'x', 40);
 162        for (i = 0; i < len ;i++) {
 163                unsigned char c = name[i];
 164                unsigned char val;
 165                if (c >= '0' && c <= '9')
 166                        val = c - '0';
 167                else if (c >= 'a' && c <= 'f')
 168                        val = c - 'a' + 10;
 169                else if (c >= 'A' && c <='F') {
 170                        val = c - 'A' + 10;
 171                        c -= 'A' - 'a';
 172                }
 173                else
 174                        return -1;
 175                canonical[i] = c;
 176                if (!(i & 1))
 177                        val <<= 4;
 178                res[i >> 1] |= val;
 179        }
 180
 181        status = find_unique_short_object(i, canonical, res, sha1);
 182        if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
 183                return error("short SHA1 %.*s is ambiguous.", len, canonical);
 184        return status;
 185}
 186
 187const char *find_unique_abbrev(const unsigned char *sha1, int len)
 188{
 189        int status;
 190        static char hex[41];
 191        memcpy(hex, sha1_to_hex(sha1), 40);
 192        while (len < 40) {
 193                unsigned char sha1_ret[20];
 194                status = get_short_sha1(hex, len, sha1_ret, 1);
 195                if (!status) {
 196                        hex[len] = 0;
 197                        return hex;
 198                }
 199                if (status != SHORT_NAME_AMBIGUOUS)
 200                        return NULL;
 201                len++;
 202        }
 203        return NULL;
 204}
 205
 206static int ambiguous_path(const char *path)
 207{
 208        int slash = 1;
 209
 210        for (;;) {
 211                switch (*path++) {
 212                case '\0':
 213                        break;
 214                case '/':
 215                        if (slash)
 216                                break;
 217                        slash = 1;
 218                        continue;
 219                case '.':
 220                        continue;
 221                default:
 222                        slash = 0;
 223                        continue;
 224                }
 225                return slash;
 226        }
 227}
 228
 229static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 230{
 231        static const char *prefix[] = {
 232                "",
 233                "refs",
 234                "refs/tags",
 235                "refs/heads",
 236                NULL
 237        };
 238        const char **p;
 239
 240        if (len == 40 && !get_sha1_hex(str, sha1))
 241                return 0;
 242
 243        /* Accept only unambiguous ref paths. */
 244        if (ambiguous_path(str))
 245                return -1;
 246
 247        for (p = prefix; *p; p++) {
 248                char *pathname = git_path("%s/%.*s", *p, len, str);
 249                if (!read_ref(pathname, sha1))
 250                        return 0;
 251        }
 252
 253        return -1;
 254}
 255
 256static int get_sha1_1(const char *name, int len, unsigned char *sha1);
 257
 258static int get_parent(const char *name, int len,
 259                      unsigned char *result, int idx)
 260{
 261        unsigned char sha1[20];
 262        int ret = get_sha1_1(name, len, sha1);
 263        struct commit *commit;
 264        struct commit_list *p;
 265
 266        if (ret)
 267                return ret;
 268        commit = lookup_commit_reference(sha1);
 269        if (!commit)
 270                return -1;
 271        if (parse_commit(commit))
 272                return -1;
 273        if (!idx) {
 274                memcpy(result, commit->object.sha1, 20);
 275                return 0;
 276        }
 277        p = commit->parents;
 278        while (p) {
 279                if (!--idx) {
 280                        memcpy(result, p->item->object.sha1, 20);
 281                        return 0;
 282                }
 283                p = p->next;
 284        }
 285        return -1;
 286}
 287
 288static int get_nth_ancestor(const char *name, int len,
 289                            unsigned char *result, int generation)
 290{
 291        unsigned char sha1[20];
 292        int ret = get_sha1_1(name, len, sha1);
 293        if (ret)
 294                return ret;
 295
 296        while (generation--) {
 297                struct commit *commit = lookup_commit_reference(sha1);
 298
 299                if (!commit || parse_commit(commit) || !commit->parents)
 300                        return -1;
 301                memcpy(sha1, commit->parents->item->object.sha1, 20);
 302        }
 303        memcpy(result, sha1, 20);
 304        return 0;
 305}
 306
 307static int peel_onion(const char *name, int len, unsigned char *sha1)
 308{
 309        unsigned char outer[20];
 310        const char *sp;
 311        const char *type_string = NULL;
 312        struct object *o;
 313
 314        /*
 315         * "ref^{type}" dereferences ref repeatedly until you cannot
 316         * dereference anymore, or you get an object of given type,
 317         * whichever comes first.  "ref^{}" means just dereference
 318         * tags until you get a non-tag.  "ref^0" is a shorthand for
 319         * "ref^{commit}".  "commit^{tree}" could be used to find the
 320         * top-level tree of the given commit.
 321         */
 322        if (len < 4 || name[len-1] != '}')
 323                return -1;
 324
 325        for (sp = name + len - 1; name <= sp; sp--) {
 326                int ch = *sp;
 327                if (ch == '{' && name < sp && sp[-1] == '^')
 328                        break;
 329        }
 330        if (sp <= name)
 331                return -1;
 332
 333        sp++; /* beginning of type name, or closing brace for empty */
 334        if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
 335                type_string = commit_type;
 336        else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
 337                type_string = tree_type;
 338        else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
 339                type_string = blob_type;
 340        else if (sp[0] == '}')
 341                type_string = NULL;
 342        else
 343                return -1;
 344
 345        if (get_sha1_1(name, sp - name - 2, outer))
 346                return -1;
 347
 348        o = parse_object(outer);
 349        if (!o)
 350                return -1;
 351        if (!type_string) {
 352                o = deref_tag(o);
 353                if (!o || (!o->parsed && !parse_object(o->sha1)))
 354                        return -1;
 355                memcpy(sha1, o->sha1, 20);
 356        }
 357        else {
 358                /* At this point, the syntax look correct, so
 359                 * if we do not get the needed object, we should
 360                 * barf.
 361                 */
 362
 363                while (1) {
 364                        if (!o || (!o->parsed && !parse_object(o->sha1)))
 365                                return -1;
 366                        if (o->type == type_string) {
 367                                memcpy(sha1, o->sha1, 20);
 368                                return 0;
 369                        }
 370                        if (o->type == tag_type)
 371                                o = ((struct tag*) o)->tagged;
 372                        else if (o->type == commit_type)
 373                                o = &(((struct commit *) o)->tree->object);
 374                        else
 375                                return error("%.*s: expected %s type, but the object dereferences to %s type",
 376                                             len, name, type_string,
 377                                             o->type);
 378                        if (!o->parsed)
 379                                parse_object(o->sha1);
 380                }
 381        }
 382        return 0;
 383}
 384
 385static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 386{
 387        int parent, ret;
 388        const char *cp;
 389
 390        /* foo^[0-9] or foo^ (== foo^1); we do not do more than 9 parents. */
 391        if (len > 2 && name[len-2] == '^' &&
 392            name[len-1] >= '0' && name[len-1] <= '9') {
 393                parent = name[len-1] - '0';
 394                len -= 2;
 395        }
 396        else if (len > 1 && name[len-1] == '^') {
 397                parent = 1;
 398                len--;
 399        } else
 400                parent = -1;
 401
 402        if (parent >= 0)
 403                return get_parent(name, len, sha1, parent);
 404
 405        /* "name~3" is "name^^^",
 406         * "name~12" is "name^^^^^^^^^^^^", and
 407         * "name~" and "name~0" are name -- not "name^0"!
 408         */
 409        parent = 0;
 410        for (cp = name + len - 1; name <= cp; cp--) {
 411                int ch = *cp;
 412                if ('0' <= ch && ch <= '9')
 413                        continue;
 414                if (ch != '~')
 415                        parent = -1;
 416                break;
 417        }
 418        if (!parent && *cp == '~') {
 419                int len1 = cp - name;
 420                cp++;
 421                while (cp < name + len)
 422                        parent = parent * 10 + *cp++ - '0';
 423                return get_nth_ancestor(name, len1, sha1, parent);
 424        }
 425
 426        ret = peel_onion(name, len, sha1);
 427        if (!ret)
 428                return 0;
 429
 430        ret = get_sha1_basic(name, len, sha1);
 431        if (!ret)
 432                return 0;
 433        return get_short_sha1(name, len, sha1, 0);
 434}
 435
 436/*
 437 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
 438 * notably "xyz^" for "parent of xyz"
 439 */
 440int get_sha1(const char *name, unsigned char *sha1)
 441{
 442        prepare_alt_odb();
 443        return get_sha1_1(name, strlen(name), sha1);
 444}