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];
  95                        nth_packed_object_sha1(p, first, now);
  96                        if (match_sha(len, match, now)) {
  97                                if (!found) {
  98                                        memcpy(found_sha1, now, 20);
  99                                        found++;
 100                                }
 101                                else if (memcmp(found_sha1, now, 20)) {
 102                                        found = 2;
 103                                        break;
 104                                }
 105                        }
 106                }
 107        }
 108        if (found == 1)
 109                memcpy(sha1, found_sha1, 20);
 110        return found;
 111}
 112
 113static int find_unique_short_object(int len, char *canonical,
 114                                    unsigned char *res, unsigned char *sha1)
 115{
 116        int has_unpacked, has_packed;
 117        unsigned char unpacked_sha1[20], packed_sha1[20];
 118
 119        has_unpacked = find_short_object_filename(len, canonical, unpacked_sha1);
 120        has_packed = find_short_packed_object(len, res, packed_sha1);
 121        if (!has_unpacked && !has_packed)
 122                return -1;
 123        if (1 < has_unpacked || 1 < has_packed)
 124                return -1;
 125        if (has_unpacked != has_packed) {
 126                memcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1), 20);
 127                return 0;
 128        }
 129        /* Both have unique ones -- do they match? */
 130        if (memcmp(packed_sha1, unpacked_sha1, 20))
 131                return -1;
 132        memcpy(sha1, packed_sha1, 20);
 133        return 0;
 134}
 135
 136static int get_short_sha1(const char *name, int len, unsigned char *sha1)
 137{
 138        int i;
 139        char canonical[40];
 140        unsigned char res[20];
 141
 142        if (len < 4)
 143                return -1;
 144        memset(res, 0, 20);
 145        memset(canonical, 'x', 40);
 146        for (i = 0; i < len ;i++) {
 147                unsigned char c = name[i];
 148                unsigned char val;
 149                if (c >= '0' && c <= '9')
 150                        val = c - '0';
 151                else if (c >= 'a' && c <= 'f')
 152                        val = c - 'a' + 10;
 153                else if (c >= 'A' && c <='F') {
 154                        val = c - 'A' + 10;
 155                        c -= 'A' - 'a';
 156                }
 157                else
 158                        return -1;
 159                canonical[i] = c;
 160                if (!(i & 1))
 161                        val <<= 4;
 162                res[i >> 1] |= val;
 163        }
 164
 165        return find_unique_short_object(i, canonical, res, sha1);
 166}
 167
 168static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 169{
 170        static const char *prefix[] = {
 171                "",
 172                "refs",
 173                "refs/tags",
 174                "refs/heads",
 175                NULL
 176        };
 177        const char **p;
 178
 179        if (len == 40 && !get_sha1_hex(str, sha1))
 180                return 0;
 181
 182        for (p = prefix; *p; p++) {
 183                char *pathname = git_path("%s/%.*s", *p, len, str);
 184                if (!read_ref(pathname, sha1))
 185                        return 0;
 186        }
 187
 188        return -1;
 189}
 190
 191static int get_sha1_1(const char *name, int len, unsigned char *sha1);
 192
 193static int get_parent(const char *name, int len,
 194                      unsigned char *result, int idx)
 195{
 196        unsigned char sha1[20];
 197        int ret = get_sha1_1(name, len, sha1);
 198        struct commit *commit;
 199        struct commit_list *p;
 200
 201        if (ret)
 202                return ret;
 203        commit = lookup_commit_reference(sha1);
 204        if (!commit)
 205                return -1;
 206        if (parse_commit(commit))
 207                return -1;
 208        if (!idx) {
 209                memcpy(result, commit->object.sha1, 20);
 210                return 0;
 211        }
 212        p = commit->parents;
 213        while (p) {
 214                if (!--idx) {
 215                        memcpy(result, p->item->object.sha1, 20);
 216                        return 0;
 217                }
 218                p = p->next;
 219        }
 220        return -1;
 221}
 222
 223static int get_nth_ancestor(const char *name, int len,
 224                            unsigned char *result, int generation)
 225{
 226        unsigned char sha1[20];
 227        int ret = get_sha1_1(name, len, sha1);
 228        if (ret)
 229                return ret;
 230
 231        while (generation--) {
 232                struct commit *commit = lookup_commit_reference(sha1);
 233
 234                if (!commit || parse_commit(commit) || !commit->parents)
 235                        return -1;
 236                memcpy(sha1, commit->parents->item->object.sha1, 20);
 237        }
 238        memcpy(result, sha1, 20);
 239        return 0;
 240}
 241
 242static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 243{
 244        int parent, ret;
 245        const char *cp;
 246
 247        /* foo^[0-9] or foo^ (== foo^1); we do not do more than 9 parents. */
 248        if (len > 2 && name[len-2] == '^' &&
 249            name[len-1] >= '0' && name[len-1] <= '9') {
 250                parent = name[len-1] - '0';
 251                len -= 2;
 252        }
 253        else if (len > 1 && name[len-1] == '^') {
 254                parent = 1;
 255                len--;
 256        } else
 257                parent = -1;
 258
 259        if (parent >= 0)
 260                return get_parent(name, len, sha1, parent);
 261
 262        /* "name~3" is "name^^^",
 263         * "name~12" is "name^^^^^^^^^^^^", and
 264         * "name~" and "name~0" are name -- not "name^0"!
 265         */
 266        parent = 0;
 267        for (cp = name + len - 1; name <= cp; cp--) {
 268                int ch = *cp;
 269                if ('0' <= ch && ch <= '9')
 270                        continue;
 271                if (ch != '~')
 272                        parent = -1;
 273                break;
 274        }
 275        if (!parent && *cp == '~') {
 276                int len1 = cp - name;
 277                cp++;
 278                while (cp < name + len)
 279                        parent = parent * 10 + *cp++ - '0';
 280                return get_nth_ancestor(name, len1, sha1, parent);
 281        }
 282
 283        ret = get_sha1_basic(name, len, sha1);
 284        if (!ret)
 285                return 0;
 286        return get_short_sha1(name, len, sha1);
 287}
 288
 289/*
 290 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
 291 * notably "xyz^" for "parent of xyz"
 292 */
 293int get_sha1(const char *name, unsigned char *sha1)
 294{
 295        prepare_alt_odb();
 296        return get_sha1_1(name, strlen(name), sha1);
 297}