git-commit-vandalism/sha1_name.c
Junio C Hamano 0bc4589020 Make sure get_sha1 does not accept ambiguous sha1 prefix (again).
The earlier fix incorrectly dropped the code the original had to
ensure the found SHA1 is at least unique within the same pack.
Restore the check.

Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-10-03 18:50:06 -07:00

307 lines
6.6 KiB
C

#include "cache.h"
#include "commit.h"
static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
{
struct alternate_object_database *alt;
char hex[40];
int found = 0;
static struct alternate_object_database *fakeent;
if (!fakeent) {
const char *objdir = get_object_directory();
int objdir_len = strlen(objdir);
int entlen = objdir_len + 43;
fakeent = xmalloc(sizeof(*fakeent) + entlen);
memcpy(fakeent->base, objdir, objdir_len);
fakeent->name = fakeent->base + objdir_len + 1;
fakeent->name[-1] = '/';
}
fakeent->next = alt_odb_list;
sprintf(hex, "%.2s", name);
for (alt = fakeent; alt && found < 2; alt = alt->next) {
struct dirent *de;
DIR *dir;
sprintf(alt->name, "%.2s/", name);
dir = opendir(alt->base);
if (!dir)
continue;
while ((de = readdir(dir)) != NULL) {
if (strlen(de->d_name) != 38)
continue;
if (memcmp(de->d_name, name + 2, len - 2))
continue;
if (!found) {
memcpy(hex + 2, de->d_name, 38);
found++;
}
else if (memcmp(hex + 2, de->d_name, 38)) {
found = 2;
break;
}
}
closedir(dir);
}
if (found == 1)
return get_sha1_hex(hex, sha1) == 0;
return found;
}
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;
unsigned char found_sha1[20];
int found = 0;
prepare_packed_git();
for (p = packed_git; p && found < 2; 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)) {
/* unique within this pack */
if (!found) {
memcpy(found_sha1, now, 20);
found++;
}
else if (memcmp(found_sha1, now, 20)) {
found = 2;
break;
}
}
else {
/* not even unique within this pack */
found = 2;
break;
}
}
}
}
if (found == 1)
memcpy(sha1, found_sha1, 20);
return found;
}
static int find_unique_short_object(int len, char *canonical,
unsigned char *res, unsigned char *sha1)
{
int has_unpacked, has_packed;
unsigned char unpacked_sha1[20], packed_sha1[20];
has_unpacked = find_short_object_filename(len, canonical, unpacked_sha1);
has_packed = find_short_packed_object(len, res, packed_sha1);
if (!has_unpacked && !has_packed)
return -1;
if (1 < has_unpacked || 1 < has_packed)
return error("short SHA1 %.*s is ambiguous.", len, canonical);
if (has_unpacked != has_packed) {
memcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1), 20);
return 0;
}
/* Both have unique ones -- do they match? */
if (memcmp(packed_sha1, unpacked_sha1, 20))
return error("short SHA1 %.*s is ambiguous.", len, canonical);
memcpy(sha1, packed_sha1, 20);
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;
}
return find_unique_short_object(i, canonical, res, sha1);
}
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)
{
prepare_alt_odb();
return get_sha1_1(name, strlen(name), sha1);
}