Andrew's git - gitweb.git/blob

   1#include "cache.h"
   2#include "commit.h"
   3
   4static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
   5{
   6        struct alternate_object_database *alt;
   7        char hex[40];
   8        int found = 0;
   9        static struct alternate_object_database *fakeent;
  10
  11        if (!fakeent) {
  12                const char *objdir = get_object_directory();
  13                int objdir_len = strlen(objdir);
  14                int entlen = objdir_len + 43;
  15                fakeent = xmalloc(sizeof(*fakeent) + entlen);
  16                memcpy(fakeent->base, objdir, objdir_len);
  17                fakeent->name = fakeent->base + objdir_len + 1;
  18                fakeent->name[-1] = '/';
  19        }
  20        fakeent->next = alt_odb_list;
  21
  22        sprintf(hex, "%.2s", name);
  23        for (alt = fakeent; alt && found < 2; alt = alt->next) {
  24                struct dirent *de;
  25                DIR *dir;
  26                sprintf(alt->name, "%.2s/", name);
  27                dir = opendir(alt->base);
  28                if (!dir)
  29                        continue;
  30                while ((de = readdir(dir)) != NULL) {
  31                        if (strlen(de->d_name) != 38)
  32                                continue;
  33                        if (memcmp(de->d_name, name + 2, len - 2))
  34                                continue;
  35                        if (!found) {
  36                                memcpy(hex + 2, de->d_name, 38);
  37                                found++;
  38                        }
  39                        else if (memcmp(hex + 2, de->d_name, 38)) {
  40                                found = 2;
  41                                break;
  42                        }
  43                }
  44                closedir(dir);
  45        }
  46        if (found == 1)
  47                return get_sha1_hex(hex, sha1) == 0;
  48        return found;
  49}
  50
  51static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
  52{
  53        do {
  54                if (*a != *b)
  55                        return 0;
  56                a++;
  57                b++;
  58                len -= 2;
  59        } while (len > 1);
  60        if (len)
  61                if ((*a ^ *b) & 0xf0)
  62                        return 0;
  63        return 1;
  64}
  65
  66static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
  67{
  68        struct packed_git *p;
  69        unsigned char found_sha1[20];
  70        int found = 0;
  71
  72        prepare_packed_git();
  73        for (p = packed_git; p && found < 2; p = p->next) {
  74                unsigned num = num_packed_objects(p);
  75                unsigned first = 0, last = num;
  76                while (first < last) {
  77                        unsigned mid = (first + last) / 2;
  78                        unsigned char now[20];
  79                        int cmp;
  80
  81                        nth_packed_object_sha1(p, mid, now);
  82                        cmp = memcmp(match, now, 20);
  83                        if (!cmp) {
  84                                first = mid;
  85                                break;
  86                        }
  87                        if (cmp > 0) {
  88                                first = mid+1;
  89                                continue;
  90                        }
  91                        last = mid;
  92                }
  93                if (first < num) {
  94                        unsigned char now[20], next[20];
  95                        nth_packed_object_sha1(p, first, now);
  96                        if (match_sha(len, match, now)) {
  97                                if (nth_packed_object_sha1(p, first+1, next) ||
  98                                    !match_sha(len, match, next)) {
  99                                        /* unique within this pack */
 100                                        if (!found) {
 101                                                memcpy(found_sha1, now, 20);
 102                                                found++;
 103                                        }
 104                                        else if (memcmp(found_sha1, now, 20)) {
 105                                                found = 2;
 106                                                break;
 107                                        }
 108                                }
 109                                else {
 110                                        /* not even unique within this pack */
 111                                        found = 2;
 112                                        break;
 113                                }
 114                        }
 115                }
 116        }
 117        if (found == 1)
 118                memcpy(sha1, found_sha1, 20);
 119        return found;
 120}
 121
 122static int find_unique_short_object(int len, char *canonical,
 123                                    unsigned char *res, unsigned char *sha1)
 124{
 125        int has_unpacked, has_packed;
 126        unsigned char unpacked_sha1[20], packed_sha1[20];
 127
 128        has_unpacked = find_short_object_filename(len, canonical, unpacked_sha1);
 129        has_packed = find_short_packed_object(len, res, packed_sha1);
 130        if (!has_unpacked && !has_packed)
 131                return -1;
 132        if (1 < has_unpacked || 1 < has_packed)
 133                return error("short SHA1 %.*s is ambiguous.", len, canonical);
 134        if (has_unpacked != has_packed) {
 135                memcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1), 20);
 136                return 0;
 137        }
 138        /* Both have unique ones -- do they match? */
 139        if (memcmp(packed_sha1, unpacked_sha1, 20))
 140                return error("short SHA1 %.*s is ambiguous.", len, canonical);
 141        memcpy(sha1, packed_sha1, 20);
 142        return 0;
 143}
 144
 145static int get_short_sha1(const char *name, int len, unsigned char *sha1)
 146{
 147        int i;
 148        char canonical[40];
 149        unsigned char res[20];
 150
 151        if (len < 4)
 152                return -1;
 153        memset(res, 0, 20);
 154        memset(canonical, 'x', 40);
 155        for (i = 0; i < len ;i++) {
 156                unsigned char c = name[i];
 157                unsigned char val;
 158                if (c >= '0' && c <= '9')
 159                        val = c - '0';
 160                else if (c >= 'a' && c <= 'f')
 161                        val = c - 'a' + 10;
 162                else if (c >= 'A' && c <='F') {
 163                        val = c - 'A' + 10;
 164                        c -= 'A' - 'a';
 165                }
 166                else
 167                        return -1;
 168                canonical[i] = c;
 169                if (!(i & 1))
 170                        val <<= 4;
 171                res[i >> 1] |= val;
 172        }
 173
 174        return find_unique_short_object(i, canonical, res, sha1);
 175}
 176
 177static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 178{
 179        static const char *prefix[] = {
 180                "",
 181                "refs",
 182                "refs/tags",
 183                "refs/heads",
 184                NULL
 185        };
 186        const char **p;
 187
 188        if (len == 40 && !get_sha1_hex(str, sha1))
 189                return 0;
 190
 191        for (p = prefix; *p; p++) {
 192                char *pathname = git_path("%s/%.*s", *p, len, str);
 193                if (!read_ref(pathname, sha1))
 194                        return 0;
 195        }
 196
 197        return -1;
 198}
 199
 200static int get_sha1_1(const char *name, int len, unsigned char *sha1);
 201
 202static int get_parent(const char *name, int len,
 203                      unsigned char *result, int idx)
 204{
 205        unsigned char sha1[20];
 206        int ret = get_sha1_1(name, len, sha1);
 207        struct commit *commit;
 208        struct commit_list *p;
 209
 210        if (ret)
 211                return ret;
 212        commit = lookup_commit_reference(sha1);
 213        if (!commit)
 214                return -1;
 215        if (parse_commit(commit))
 216                return -1;
 217        if (!idx) {
 218                memcpy(result, commit->object.sha1, 20);
 219                return 0;
 220        }
 221        p = commit->parents;
 222        while (p) {
 223                if (!--idx) {
 224                        memcpy(result, p->item->object.sha1, 20);
 225                        return 0;
 226                }
 227                p = p->next;
 228        }
 229        return -1;
 230}
 231
 232static int get_nth_ancestor(const char *name, int len,
 233                            unsigned char *result, int generation)
 234{
 235        unsigned char sha1[20];
 236        int ret = get_sha1_1(name, len, sha1);
 237        if (ret)
 238                return ret;
 239
 240        while (generation--) {
 241                struct commit *commit = lookup_commit_reference(sha1);
 242
 243                if (!commit || parse_commit(commit) || !commit->parents)
 244                        return -1;
 245                memcpy(sha1, commit->parents->item->object.sha1, 20);
 246        }
 247        memcpy(result, sha1, 20);
 248        return 0;
 249}
 250
 251static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 252{
 253        int parent, ret;
 254        const char *cp;
 255
 256        /* foo^[0-9] or foo^ (== foo^1); we do not do more than 9 parents. */
 257        if (len > 2 && name[len-2] == '^' &&
 258            name[len-1] >= '0' && name[len-1] <= '9') {
 259                parent = name[len-1] - '0';
 260                len -= 2;
 261        }
 262        else if (len > 1 && name[len-1] == '^') {
 263                parent = 1;
 264                len--;
 265        } else
 266                parent = -1;
 267
 268        if (parent >= 0)
 269                return get_parent(name, len, sha1, parent);
 270
 271        /* "name~3" is "name^^^",
 272         * "name~12" is "name^^^^^^^^^^^^", and
 273         * "name~" and "name~0" are name -- not "name^0"!
 274         */
 275        parent = 0;
 276        for (cp = name + len - 1; name <= cp; cp--) {
 277                int ch = *cp;
 278                if ('0' <= ch && ch <= '9')
 279                        continue;
 280                if (ch != '~')
 281                        parent = -1;
 282                break;
 283        }
 284        if (!parent && *cp == '~') {
 285                int len1 = cp - name;
 286                cp++;
 287                while (cp < name + len)
 288                        parent = parent * 10 + *cp++ - '0';
 289                return get_nth_ancestor(name, len1, sha1, parent);
 290        }
 291
 292        ret = get_sha1_basic(name, len, sha1);
 293        if (!ret)
 294                return 0;
 295        return get_short_sha1(name, len, sha1);
 296}
 297
 298/*
 299 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
 300 * notably "xyz^" for "parent of xyz"
 301 */
 302int get_sha1(const char *name, unsigned char *sha1)
 303{
 304        prepare_alt_odb();
 305        return get_sha1_1(name, strlen(name), sha1);
 306}