mirror of
https://github.com/git/git
synced 2024-07-17 02:57:48 +00:00
011fbc7f07
This removes the misguided attempt to refuse processing a branch
name xyzzy and insist it to be given as either heads/xyzzy or
tags/xyzzy when a tag xyzzy exists. There was no reason to do
so --- the search order was predictable and well defined, so if
the user says xyzzy we should have taken the tag xyzzy in such a
case without complaining.
This incidentally fixes another subtle bug related to this. If
such a duplicate branch/tag name happened to be a unique valid
prefix of an existing commit object name (say, "beef"), we did
not take the tag "beef" but after complaining used the commit
object whose name started with beef.
Another problem this fixes while introducing some confusion is
that there is no longer a reason to forbid a branch name HEAD
anymore. In other words, now "git pull . ref1:HEAD" would work
as expected, once we revert "We do not like HEAD branch" patch.
It creates "HEAD" branch under ${GIT_DIR-.git}/refs/heads (or
fast-forwards if already exists) using the tip of ref1 branch
from the current repository, and merges it into the current
branch.
Signed-off-by: Junio C Hamano <junkio@cox.net>
446 lines
9.7 KiB
C
446 lines
9.7 KiB
C
#include "cache.h"
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#include "tag.h"
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#include "commit.h"
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#include "tree.h"
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#include "blob.h"
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static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
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{
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struct alternate_object_database *alt;
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char hex[40];
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int found = 0;
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static struct alternate_object_database *fakeent;
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if (!fakeent) {
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const char *objdir = get_object_directory();
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int objdir_len = strlen(objdir);
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int entlen = objdir_len + 43;
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fakeent = xmalloc(sizeof(*fakeent) + entlen);
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memcpy(fakeent->base, objdir, objdir_len);
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fakeent->name = fakeent->base + objdir_len + 1;
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fakeent->name[-1] = '/';
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}
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fakeent->next = alt_odb_list;
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sprintf(hex, "%.2s", name);
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for (alt = fakeent; alt && found < 2; alt = alt->next) {
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struct dirent *de;
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DIR *dir;
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sprintf(alt->name, "%.2s/", name);
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dir = opendir(alt->base);
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if (!dir)
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continue;
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while ((de = readdir(dir)) != NULL) {
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if (strlen(de->d_name) != 38)
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continue;
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if (memcmp(de->d_name, name + 2, len - 2))
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continue;
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if (!found) {
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memcpy(hex + 2, de->d_name, 38);
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found++;
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}
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else if (memcmp(hex + 2, de->d_name, 38)) {
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found = 2;
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break;
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}
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}
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closedir(dir);
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}
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if (found == 1)
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return get_sha1_hex(hex, sha1) == 0;
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return found;
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}
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static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
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{
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do {
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if (*a != *b)
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return 0;
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a++;
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b++;
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len -= 2;
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} while (len > 1);
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if (len)
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if ((*a ^ *b) & 0xf0)
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return 0;
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return 1;
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}
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static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
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{
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struct packed_git *p;
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unsigned char found_sha1[20];
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int found = 0;
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prepare_packed_git();
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for (p = packed_git; p && found < 2; p = p->next) {
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unsigned num = num_packed_objects(p);
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unsigned first = 0, last = num;
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while (first < last) {
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unsigned mid = (first + last) / 2;
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unsigned char now[20];
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int cmp;
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nth_packed_object_sha1(p, mid, now);
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cmp = memcmp(match, now, 20);
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if (!cmp) {
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first = mid;
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break;
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}
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if (cmp > 0) {
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first = mid+1;
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continue;
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}
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last = mid;
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}
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if (first < num) {
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unsigned char now[20], next[20];
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nth_packed_object_sha1(p, first, now);
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if (match_sha(len, match, now)) {
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if (nth_packed_object_sha1(p, first+1, next) ||
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!match_sha(len, match, next)) {
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/* unique within this pack */
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if (!found) {
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memcpy(found_sha1, now, 20);
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found++;
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}
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else if (memcmp(found_sha1, now, 20)) {
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found = 2;
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break;
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}
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}
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else {
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/* not even unique within this pack */
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found = 2;
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break;
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}
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}
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}
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}
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if (found == 1)
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memcpy(sha1, found_sha1, 20);
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return found;
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}
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#define SHORT_NAME_NOT_FOUND (-1)
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#define SHORT_NAME_AMBIGUOUS (-2)
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static int find_unique_short_object(int len, char *canonical,
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unsigned char *res, unsigned char *sha1)
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{
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int has_unpacked, has_packed;
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unsigned char unpacked_sha1[20], packed_sha1[20];
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has_unpacked = find_short_object_filename(len, canonical, unpacked_sha1);
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has_packed = find_short_packed_object(len, res, packed_sha1);
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if (!has_unpacked && !has_packed)
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return SHORT_NAME_NOT_FOUND;
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if (1 < has_unpacked || 1 < has_packed)
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return SHORT_NAME_AMBIGUOUS;
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if (has_unpacked != has_packed) {
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memcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1), 20);
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return 0;
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}
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/* Both have unique ones -- do they match? */
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if (memcmp(packed_sha1, unpacked_sha1, 20))
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return -2;
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memcpy(sha1, packed_sha1, 20);
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return 0;
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}
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static int get_short_sha1(const char *name, int len, unsigned char *sha1,
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int quietly)
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{
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int i, status;
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char canonical[40];
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unsigned char res[20];
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if (len < 4)
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return -1;
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memset(res, 0, 20);
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memset(canonical, 'x', 40);
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for (i = 0; i < len ;i++) {
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unsigned char c = name[i];
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unsigned char val;
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if (c >= '0' && c <= '9')
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val = c - '0';
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else if (c >= 'a' && c <= 'f')
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val = c - 'a' + 10;
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else if (c >= 'A' && c <='F') {
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val = c - 'A' + 10;
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c -= 'A' - 'a';
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}
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else
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return -1;
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canonical[i] = c;
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if (!(i & 1))
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val <<= 4;
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res[i >> 1] |= val;
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}
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status = find_unique_short_object(i, canonical, res, sha1);
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if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
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return error("short SHA1 %.*s is ambiguous.", len, canonical);
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return status;
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}
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const char *find_unique_abbrev(const unsigned char *sha1, int len)
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{
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int status;
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static char hex[41];
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memcpy(hex, sha1_to_hex(sha1), 40);
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while (len < 40) {
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unsigned char sha1_ret[20];
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status = get_short_sha1(hex, len, sha1_ret, 1);
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if (!status) {
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hex[len] = 0;
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return hex;
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}
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if (status != SHORT_NAME_AMBIGUOUS)
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return NULL;
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len++;
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}
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return NULL;
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}
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static int ambiguous_path(const char *path, int len)
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{
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int slash = 1;
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int cnt;
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for (cnt = 0; cnt < len; cnt++) {
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switch (*path++) {
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case '\0':
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break;
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case '/':
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if (slash)
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break;
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slash = 1;
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continue;
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case '.':
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continue;
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default:
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slash = 0;
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continue;
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}
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return slash;
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}
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return slash;
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}
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static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
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{
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static const char *prefix[] = {
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"",
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"refs",
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"refs/tags",
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"refs/heads",
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NULL
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};
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const char **p;
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if (len == 40 && !get_sha1_hex(str, sha1))
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return 0;
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/* Accept only unambiguous ref paths. */
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if (ambiguous_path(str, len))
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return -1;
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for (p = prefix; *p; p++) {
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char *pathname = git_path("%s/%.*s", *p, len, str);
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if (!read_ref(pathname, sha1))
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return 0;
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}
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return -1;
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}
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static int get_sha1_1(const char *name, int len, unsigned char *sha1);
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static int get_parent(const char *name, int len,
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unsigned char *result, int idx)
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{
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unsigned char sha1[20];
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int ret = get_sha1_1(name, len, sha1);
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struct commit *commit;
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struct commit_list *p;
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if (ret)
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return ret;
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commit = lookup_commit_reference(sha1);
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if (!commit)
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return -1;
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if (parse_commit(commit))
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return -1;
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if (!idx) {
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memcpy(result, commit->object.sha1, 20);
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return 0;
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}
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p = commit->parents;
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while (p) {
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if (!--idx) {
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memcpy(result, p->item->object.sha1, 20);
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return 0;
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}
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p = p->next;
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}
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return -1;
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}
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static int get_nth_ancestor(const char *name, int len,
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unsigned char *result, int generation)
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{
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unsigned char sha1[20];
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int ret = get_sha1_1(name, len, sha1);
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if (ret)
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return ret;
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while (generation--) {
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struct commit *commit = lookup_commit_reference(sha1);
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if (!commit || parse_commit(commit) || !commit->parents)
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return -1;
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memcpy(sha1, commit->parents->item->object.sha1, 20);
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}
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memcpy(result, sha1, 20);
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return 0;
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}
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static int peel_onion(const char *name, int len, unsigned char *sha1)
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{
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unsigned char outer[20];
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const char *sp;
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const char *type_string = NULL;
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struct object *o;
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/*
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* "ref^{type}" dereferences ref repeatedly until you cannot
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* dereference anymore, or you get an object of given type,
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* whichever comes first. "ref^{}" means just dereference
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* tags until you get a non-tag. "ref^0" is a shorthand for
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* "ref^{commit}". "commit^{tree}" could be used to find the
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* top-level tree of the given commit.
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*/
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if (len < 4 || name[len-1] != '}')
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return -1;
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for (sp = name + len - 1; name <= sp; sp--) {
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int ch = *sp;
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if (ch == '{' && name < sp && sp[-1] == '^')
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break;
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}
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if (sp <= name)
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return -1;
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sp++; /* beginning of type name, or closing brace for empty */
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if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
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type_string = commit_type;
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else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
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type_string = tree_type;
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else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
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type_string = blob_type;
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else if (sp[0] == '}')
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type_string = NULL;
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else
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return -1;
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if (get_sha1_1(name, sp - name - 2, outer))
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return -1;
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o = parse_object(outer);
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if (!o)
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return -1;
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if (!type_string) {
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o = deref_tag(o, name, sp - name - 2);
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if (!o || (!o->parsed && !parse_object(o->sha1)))
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return -1;
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memcpy(sha1, o->sha1, 20);
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}
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else {
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/* At this point, the syntax look correct, so
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* if we do not get the needed object, we should
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* barf.
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*/
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while (1) {
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if (!o || (!o->parsed && !parse_object(o->sha1)))
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return -1;
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if (o->type == type_string) {
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memcpy(sha1, o->sha1, 20);
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return 0;
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}
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if (o->type == tag_type)
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o = ((struct tag*) o)->tagged;
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else if (o->type == commit_type)
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o = &(((struct commit *) o)->tree->object);
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else
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return error("%.*s: expected %s type, but the object dereferences to %s type",
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len, name, type_string,
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o->type);
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if (!o->parsed)
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parse_object(o->sha1);
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}
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}
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return 0;
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}
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static int get_sha1_1(const char *name, int len, unsigned char *sha1)
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{
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int parent, ret;
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const char *cp;
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/* foo^[0-9] or foo^ (== foo^1); we do not do more than 9 parents. */
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if (len > 2 && name[len-2] == '^' &&
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name[len-1] >= '0' && name[len-1] <= '9') {
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parent = name[len-1] - '0';
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len -= 2;
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}
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else if (len > 1 && name[len-1] == '^') {
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parent = 1;
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len--;
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} else
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parent = -1;
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if (parent >= 0)
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return get_parent(name, len, sha1, parent);
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/* "name~3" is "name^^^",
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* "name~12" is "name^^^^^^^^^^^^", and
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* "name~" and "name~0" are name -- not "name^0"!
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*/
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parent = 0;
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for (cp = name + len - 1; name <= cp; cp--) {
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int ch = *cp;
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if ('0' <= ch && ch <= '9')
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continue;
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if (ch != '~')
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parent = -1;
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break;
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}
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if (!parent && *cp == '~') {
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int len1 = cp - name;
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cp++;
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while (cp < name + len)
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parent = parent * 10 + *cp++ - '0';
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return get_nth_ancestor(name, len1, sha1, parent);
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}
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ret = peel_onion(name, len, sha1);
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if (!ret)
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return 0;
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ret = get_sha1_basic(name, len, sha1);
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if (!ret)
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return 0;
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return get_short_sha1(name, len, sha1, 0);
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}
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/*
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* This is like "get_sha1_basic()", except it allows "sha1 expressions",
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* notably "xyz^" for "parent of xyz"
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*/
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int get_sha1(const char *name, unsigned char *sha1)
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{
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prepare_alt_odb();
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return get_sha1_1(name, strlen(name), sha1);
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}
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