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#include "cache.h"
#include "commit.h"
static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
{
static char dirname[PATH_MAX];
char hex[40];
DIR *dir;
int found;
snprintf(dirname, sizeof(dirname), "%s/%.2s", get_object_directory(), name);
dir = opendir(dirname);
sprintf(hex, "%.2s", name);
found = 0;
if (dir) {
struct dirent *de;
while ((de = readdir(dir)) != NULL) {
if (strlen(de->d_name) != 38)
continue;
if (memcmp(de->d_name, name + 2, len-2))
continue;
memcpy(hex + 2, de->d_name, 38);
if (++found > 1)
break;
}
closedir(dir);
}
if (found == 1)
return get_sha1_hex(hex, sha1) == 0;
return 0;
}
static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
{
do {
if (*a != *b)
return 0;
a++;
b++;
len -= 2;
} while (len > 1);
if (len)
if ((*a ^ *b) & 0xf0)
return 0;
return 1;
}
static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
{
struct packed_git *p;
prepare_packed_git();
for (p = packed_git; p; p = p->next) {
unsigned num = num_packed_objects(p);
unsigned first = 0, last = num;
while (first < last) {
unsigned mid = (first + last) / 2;
unsigned char now[20];
int cmp;
nth_packed_object_sha1(p, mid, now);
cmp = memcmp(match, now, 20);
if (!cmp) {
first = mid;
break;
}
if (cmp > 0) {
first = mid+1;
continue;
}
last = mid;
}
if (first < num) {
unsigned char now[20], next[20];
nth_packed_object_sha1(p, first, now);
if (match_sha(len, match, now)) {
if (nth_packed_object_sha1(p, first+1, next) || !match_sha(len, match, next)) {
memcpy(sha1, now, 20);
return 1;
}
}
}
}
return 0;
}
static int get_short_sha1(const char *name, int len, unsigned char *sha1)
{
int i;
char canonical[40];
unsigned char res[20];
if (len < 4)
return -1;
memset(res, 0, 20);
memset(canonical, 'x', 40);
for (i = 0; i < len ;i++) {
unsigned char c = name[i];
unsigned char val;
if (c >= '0' && c <= '9')
val = c - '0';
else if (c >= 'a' && c <= 'f')
val = c - 'a' + 10;
else if (c >= 'A' && c <='F') {
val = c - 'A' + 10;
c -= 'A' - 'a';
}
else
return -1;
canonical[i] = c;
if (!(i & 1))
val <<= 4;
res[i >> 1] |= val;
}
if (find_short_object_filename(i, canonical, sha1))
return 0;
if (find_short_packed_object(i, res, sha1))
return 0;
return -1;
}
static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
{
static const char *prefix[] = {
"",
"refs",
"refs/tags",
"refs/heads",
NULL
};
const char **p;
if (len == 40 && !get_sha1_hex(str, sha1))
return 0;
for (p = prefix; *p; p++) {
char *pathname = git_path("%s/%.*s", *p, len, str);
if (!read_ref(pathname, sha1))
return 0;
}
return -1;
}
static int get_sha1_1(const char *name, int len, unsigned char *sha1);
static int get_parent(const char *name, int len,
unsigned char *result, int idx)
{
unsigned char sha1[20];
int ret = get_sha1_1(name, len, sha1);
struct commit *commit;
struct commit_list *p;
if (ret)
return ret;
commit = lookup_commit_reference(sha1);
if (!commit)
return -1;
if (parse_commit(commit))
return -1;
if (!idx) {
memcpy(result, commit->object.sha1, 20);
return 0;
}
p = commit->parents;
while (p) {
if (!--idx) {
memcpy(result, p->item->object.sha1, 20);
return 0;
}
p = p->next;
}
return -1;
}
static int get_nth_ancestor(const char *name, int len,
unsigned char *result, int generation)
{
unsigned char sha1[20];
int ret = get_sha1_1(name, len, sha1);
if (ret)
return ret;
while (generation--) {
struct commit *commit = lookup_commit_reference(sha1);
if (!commit || parse_commit(commit) || !commit->parents)
return -1;
memcpy(sha1, commit->parents->item->object.sha1, 20);
}
memcpy(result, sha1, 20);
return 0;
}
static int get_sha1_1(const char *name, int len, unsigned char *sha1)
{
int parent, ret;
const char *cp;
/* foo^[0-9] or foo^ (== foo^1); we do not do more than 9 parents. */
if (len > 2 && name[len-2] == '^' &&
name[len-1] >= '0' && name[len-1] <= '9') {
parent = name[len-1] - '0';
len -= 2;
}
else if (len > 1 && name[len-1] == '^') {
parent = 1;
len--;
} else
parent = -1;
if (parent >= 0)
return get_parent(name, len, sha1, parent);
/* "name~3" is "name^^^",
* "name~12" is "name^^^^^^^^^^^^", and
* "name~" and "name~0" are name -- not "name^0"!
*/
parent = 0;
for (cp = name + len - 1; name <= cp; cp--) {
int ch = *cp;
if ('0' <= ch && ch <= '9')
continue;
if (ch != '~')
parent = -1;
break;
}
if (!parent && *cp == '~') {
int len1 = cp - name;
cp++;
while (cp < name + len)
parent = parent * 10 + *cp++ - '0';
return get_nth_ancestor(name, len1, sha1, parent);
}
ret = get_sha1_basic(name, len, sha1);
if (!ret)
return 0;
return get_short_sha1(name, len, sha1);
}
/*
* This is like "get_sha1_basic()", except it allows "sha1 expressions",
* notably "xyz^" for "parent of xyz"
*/
int get_sha1(const char *name, unsigned char *sha1)
{
return get_sha1_1(name, strlen(name), sha1);
}
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