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, unsigned char *sha1)
  88{
  89        int i;
  90        char canonical[40];
  91        unsigned char res[20];
  92
  93        memset(res, 0, 20);
  94        memset(canonical, 'x', 40);
  95        for (i = 0;;i++) {
  96                unsigned char c = name[i];
  97                unsigned char val;
  98                if (!c || i > 40)
  99                        break;
 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 (i < 4)
 116                return -1;
 117        if (find_short_object_filename(i, canonical, sha1))
 118                return 0;
 119        if (find_short_packed_object(i, res, sha1))
 120                return 0;
 121        return -1;
 122}
 123
 124static int get_sha1_file(const char *path, unsigned char *result)
 125{
 126        char buffer[60];
 127        int fd = open(path, O_RDONLY);
 128        int len;
 129
 130        if (fd < 0)
 131                return -1;
 132        len = read(fd, buffer, sizeof(buffer));
 133        close(fd);
 134        if (len < 40)
 135                return -1;
 136        return get_sha1_hex(buffer, result);
 137}
 138
 139static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 140{
 141        static const char *prefix[] = {
 142                "",
 143                "refs",
 144                "refs/tags",
 145                "refs/heads",
 146                "refs/snap",
 147                NULL
 148        };
 149        const char **p;
 150
 151        if (!get_sha1_hex(str, sha1))
 152                return 0;
 153
 154        for (p = prefix; *p; p++) {
 155                char *pathname = git_path("%s/%.*s", *p, len, str);
 156                if (!get_sha1_file(pathname, sha1))
 157                        return 0;
 158        }
 159
 160        return -1;
 161}
 162
 163static int get_sha1_1(const char *name, int len, unsigned char *sha1);
 164
 165static int get_parent(const char *name, int len,
 166                      unsigned char *result, int idx)
 167{
 168        unsigned char sha1[20];
 169        int ret = get_sha1_1(name, len, sha1);
 170        struct commit *commit;
 171        struct commit_list *p;
 172
 173        if (ret)
 174                return ret;
 175        commit = lookup_commit_reference(sha1);
 176        if (!commit)
 177                return -1;
 178        if (parse_commit(commit))
 179                return -1;
 180        if (!idx) {
 181                memcpy(result, commit->object.sha1, 20);
 182                return 0;
 183        }
 184        p = commit->parents;
 185        while (p) {
 186                if (!--idx) {
 187                        memcpy(result, p->item->object.sha1, 20);
 188                        return 0;
 189                }
 190                p = p->next;
 191        }
 192        return -1;
 193}
 194
 195static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 196{
 197        int parent, ret;
 198
 199        /* foo^[0-9] or foo^ (== foo^1); we do not do more than 9 parents. */
 200        if (len > 2 && name[len-2] == '^' &&
 201            name[len-1] >= '0' && name[len-1] <= '9') {
 202                parent = name[len-1] - '0';
 203                len -= 2;
 204        }
 205        else if (len > 1 && name[len-1] == '^')
 206                parent = 1;
 207        else
 208                parent = -1;
 209
 210        if (0 <= parent) {
 211                ret = get_parent(name, len-1, sha1, parent);
 212                if (!ret)
 213                        return 0;
 214        }
 215        ret = get_sha1_basic(name, len, sha1);
 216        if (!ret)
 217                return 0;
 218        return get_short_sha1(name, sha1);
 219}
 220
 221/*
 222 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
 223 * notably "xyz^" for "parent of xyz"
 224 */
 225int get_sha1(const char *name, unsigned char *sha1)
 226{
 227        return get_sha1_1(name, strlen(name), sha1);
 228}