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        static char dirname[PATH_MAX];
   7        char hex[40];
   8        DIR *dir;
   9        int found;
  10
  11        snprintf(dirname, sizeof(dirname), "%s/%.2s", get_object_directory(), name);
  12        dir = opendir(dirname);
  13        sprintf(hex, "%.2s", name);
  14        found = 0;
  15        if (dir) {
  16                struct dirent *de;
  17                while ((de = readdir(dir)) != NULL) {
  18                        if (strlen(de->d_name) != 38)
  19                                continue;
  20                        if (memcmp(de->d_name, name + 2, len-2))
  21                                continue;
  22                        memcpy(hex + 2, de->d_name, 38);
  23                        if (++found > 1)
  24                                break;
  25                }
  26                closedir(dir);
  27        }
  28        if (found == 1)
  29                return get_sha1_hex(hex, sha1) == 0;
  30        return 0;
  31}
  32
  33static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
  34{
  35        do {
  36                if (*a != *b)
  37                        return 0;
  38                a++;
  39                b++;
  40                len -= 2;
  41        } while (len > 1);
  42        if (len)
  43                if ((*a ^ *b) & 0xf0)
  44                        return 0;
  45        return 1;
  46}
  47
  48static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
  49{
  50        struct packed_git *p;
  51
  52        prepare_packed_git();
  53        for (p = packed_git; p; p = p->next) {
  54                unsigned num = num_packed_objects(p);
  55                unsigned first = 0, last = num;
  56                while (first < last) {
  57                        unsigned mid = (first + last) / 2;
  58                        unsigned char now[20];
  59                        int cmp;
  60
  61                        nth_packed_object_sha1(p, mid, now);
  62                        cmp = memcmp(match, now, 20);
  63                        if (!cmp) {
  64                                first = mid;
  65                                break;
  66                        }
  67                        if (cmp > 0) {
  68                                first = mid+1;
  69                                continue;
  70                        }
  71                        last = mid;
  72                }
  73                if (first < num) {
  74                        unsigned char now[20], next[20];
  75                        nth_packed_object_sha1(p, first, now);
  76                        if (match_sha(len, match, now)) {
  77                                if (nth_packed_object_sha1(p, first+1, next) || !match_sha(len, match, next)) {
  78                                        memcpy(sha1, now, 20);
  79                                        return 1;
  80                                }
  81                        }
  82                }
  83        }
  84        return 0;
  85}
  86
  87static int get_short_sha1(const char *name, int len, unsigned char *sha1)
  88{
  89        int i;
  90        char canonical[40];
  91        unsigned char res[20];
  92
  93        if (len < 4)
  94                return -1;
  95        memset(res, 0, 20);
  96        memset(canonical, 'x', 40);
  97        for (i = 0; i < len ;i++) {
  98                unsigned char c = name[i];
  99                unsigned char val;
 100                if (c >= '0' && c <= '9')
 101                        val = c - '0';
 102                else if (c >= 'a' && c <= 'f')
 103                        val = c - 'a' + 10;
 104                else if (c >= 'A' && c <='F') {
 105                        val = c - 'A' + 10;
 106                        c -= 'A' - 'a';
 107                }
 108                else
 109                        return -1;
 110                canonical[i] = c;
 111                if (!(i & 1))
 112                        val <<= 4;
 113                res[i >> 1] |= val;
 114        }
 115        if (find_short_object_filename(i, canonical, sha1))
 116                return 0;
 117        if (find_short_packed_object(i, res, sha1))
 118                return 0;
 119        return -1;
 120}
 121
 122static int get_sha1_file(const char *path, unsigned char *result)
 123{
 124        char buffer[60];
 125        int fd = open(path, O_RDONLY);
 126        int len;
 127
 128        if (fd < 0)
 129                return -1;
 130        len = read(fd, buffer, sizeof(buffer));
 131        close(fd);
 132        if (len < 40)
 133                return -1;
 134        return get_sha1_hex(buffer, result);
 135}
 136
 137static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 138{
 139        static const char *prefix[] = {
 140                "",
 141                "refs",
 142                "refs/tags",
 143                "refs/heads",
 144                NULL
 145        };
 146        const char **p;
 147
 148        if (len == 40 && !get_sha1_hex(str, sha1))
 149                return 0;
 150
 151        for (p = prefix; *p; p++) {
 152                char *pathname = git_path("%s/%.*s", *p, len, str);
 153                if (!get_sha1_file(pathname, sha1))
 154                        return 0;
 155        }
 156
 157        return -1;
 158}
 159
 160static int get_sha1_1(const char *name, int len, unsigned char *sha1);
 161
 162static int get_parent(const char *name, int len,
 163                      unsigned char *result, int idx)
 164{
 165        unsigned char sha1[20];
 166        int ret = get_sha1_1(name, len, sha1);
 167        struct commit *commit;
 168        struct commit_list *p;
 169
 170        if (ret)
 171                return ret;
 172        commit = lookup_commit_reference(sha1);
 173        if (!commit)
 174                return -1;
 175        if (parse_commit(commit))
 176                return -1;
 177        if (!idx) {
 178                memcpy(result, commit->object.sha1, 20);
 179                return 0;
 180        }
 181        p = commit->parents;
 182        while (p) {
 183                if (!--idx) {
 184                        memcpy(result, p->item->object.sha1, 20);
 185                        return 0;
 186                }
 187                p = p->next;
 188        }
 189        return -1;
 190}
 191
 192static int get_nth_ancestor(const char *name, int len,
 193                            unsigned char *result, int generation)
 194{
 195        unsigned char sha1[20];
 196        int ret = get_sha1_1(name, len, sha1);
 197        if (ret)
 198                return ret;
 199
 200        while (generation--) {
 201                struct commit *commit = lookup_commit_reference(sha1);
 202
 203                if (!commit || parse_commit(commit) || !commit->parents)
 204                        return -1;
 205                memcpy(sha1, commit->parents->item->object.sha1, 20);
 206        }
 207        memcpy(result, sha1, 20);
 208        return 0;
 209}
 210
 211static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 212{
 213        int parent, ret;
 214        const char *cp;
 215
 216        /* foo^[0-9] or foo^ (== foo^1); we do not do more than 9 parents. */
 217        if (len > 2 && name[len-2] == '^' &&
 218            name[len-1] >= '0' && name[len-1] <= '9') {
 219                parent = name[len-1] - '0';
 220                len -= 2;
 221        }
 222        else if (len > 1 && name[len-1] == '^') {
 223                parent = 1;
 224                len--;
 225        } else
 226                parent = -1;
 227
 228        if (parent >= 0)
 229                return get_parent(name, len, sha1, parent);
 230
 231        /* "name~3" is "name^^^",
 232         * "name~12" is "name^^^^^^^^^^^^", and
 233         * "name~" and "name~0" are name -- not "name^0"!
 234         */
 235        parent = 0;
 236        for (cp = name + len - 1; name <= cp; cp--) {
 237                int ch = *cp;
 238                if ('0' <= ch && ch <= '9')
 239                        continue;
 240                if (ch != '~')
 241                        parent = -1;
 242                break;
 243        }
 244        if (!parent && *cp == '~') {
 245                int len1 = cp - name;
 246                cp++;
 247                while (cp < name + len)
 248                        parent = parent * 10 + *cp++ - '0';
 249                return get_nth_ancestor(name, len1, sha1, parent);
 250        }
 251
 252        ret = get_sha1_basic(name, len, sha1);
 253        if (!ret)
 254                return 0;
 255        return get_short_sha1(name, len, sha1);
 256}
 257
 258/*
 259 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
 260 * notably "xyz^" for "parent of xyz"
 261 */
 262int get_sha1(const char *name, unsigned char *sha1)
 263{
 264        return get_sha1_1(name, strlen(name), sha1);
 265}