git/sha1_name.c
Johannes Schindelin 28a4d94044 object name: introduce ':/<oneline prefix>' notation
To name a commit, you can now say

	$ git rev-parse ':/Initial revision of "git"'

and it will return the hash of the youngest commit whose
commit message (the oneline) begins with the given prefix.

For future extension, a leading exclamation mark is treated
specially: if you want to match a commit message starting with
a '!', just repeat the exclamation mark. So, to match a commit
which starts with '!Hello World', use

	$ git show ':/!!Hello World'

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-02-24 02:06:18 -08:00

706 lines
16 KiB
C

#include "cache.h"
#include "tag.h"
#include "commit.h"
#include "tree.h"
#include "blob.h"
#include "tree-walk.h"
#include "refs.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 = hashcmp(match, now);
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) {
hashcpy(found_sha1, now);
found++;
}
else if (hashcmp(found_sha1, now)) {
found = 2;
break;
}
}
else {
/* not even unique within this pack */
found = 2;
break;
}
}
}
}
if (found == 1)
hashcpy(sha1, found_sha1);
return found;
}
#define SHORT_NAME_NOT_FOUND (-1)
#define SHORT_NAME_AMBIGUOUS (-2)
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 SHORT_NAME_NOT_FOUND;
if (1 < has_unpacked || 1 < has_packed)
return SHORT_NAME_AMBIGUOUS;
if (has_unpacked != has_packed) {
hashcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1));
return 0;
}
/* Both have unique ones -- do they match? */
if (hashcmp(packed_sha1, unpacked_sha1))
return SHORT_NAME_AMBIGUOUS;
hashcpy(sha1, packed_sha1);
return 0;
}
static int get_short_sha1(const char *name, int len, unsigned char *sha1,
int quietly)
{
int i, status;
char canonical[40];
unsigned char res[20];
if (len < MINIMUM_ABBREV || len > 40)
return -1;
hashclr(res);
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;
}
status = find_unique_short_object(i, canonical, res, sha1);
if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
return error("short SHA1 %.*s is ambiguous.", len, canonical);
return status;
}
const char *find_unique_abbrev(const unsigned char *sha1, int len)
{
int status, is_null;
static char hex[41];
is_null = is_null_sha1(sha1);
memcpy(hex, sha1_to_hex(sha1), 40);
if (len == 40 || !len)
return hex;
while (len < 40) {
unsigned char sha1_ret[20];
status = get_short_sha1(hex, len, sha1_ret, 1);
if (!status ||
(is_null && status != SHORT_NAME_AMBIGUOUS)) {
hex[len] = 0;
return hex;
}
if (status != SHORT_NAME_AMBIGUOUS)
return NULL;
len++;
}
return NULL;
}
static int ambiguous_path(const char *path, int len)
{
int slash = 1;
int cnt;
for (cnt = 0; cnt < len; cnt++) {
switch (*path++) {
case '\0':
break;
case '/':
if (slash)
break;
slash = 1;
continue;
case '.':
continue;
default:
slash = 0;
continue;
}
break;
}
return slash;
}
static const char *ref_fmt[] = {
"%.*s",
"refs/%.*s",
"refs/tags/%.*s",
"refs/heads/%.*s",
"refs/remotes/%.*s",
"refs/remotes/%.*s/HEAD",
NULL
};
int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
{
const char **p, *r;
int refs_found = 0;
*ref = NULL;
for (p = ref_fmt; *p; p++) {
unsigned char sha1_from_ref[20];
unsigned char *this_result;
this_result = refs_found ? sha1_from_ref : sha1;
r = resolve_ref(mkpath(*p, len, str), this_result, 1, NULL);
if (r) {
if (!refs_found++)
*ref = xstrdup(r);
if (!warn_ambiguous_refs)
break;
}
}
return refs_found;
}
int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
{
const char **p;
int logs_found = 0;
*log = NULL;
for (p = ref_fmt; *p; p++) {
struct stat st;
unsigned char hash[20];
char path[PATH_MAX];
const char *ref, *it;
strcpy(path, mkpath(*p, len, str));
ref = resolve_ref(path, hash, 0, NULL);
if (!ref)
continue;
if (!stat(git_path("logs/%s", path), &st) &&
S_ISREG(st.st_mode))
it = path;
else if (strcmp(ref, path) &&
!stat(git_path("logs/%s", ref), &st) &&
S_ISREG(st.st_mode))
it = ref;
else
continue;
if (!logs_found++) {
*log = xstrdup(it);
hashcpy(sha1, hash);
}
if (!warn_ambiguous_refs)
break;
}
return logs_found;
}
static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
{
static const char *warning = "warning: refname '%.*s' is ambiguous.\n";
char *real_ref = NULL;
int refs_found = 0;
int at, reflog_len;
if (len == 40 && !get_sha1_hex(str, sha1))
return 0;
/* basic@{time or number} format to query ref-log */
reflog_len = at = 0;
if (str[len-1] == '}') {
for (at = 0; at < len - 1; at++) {
if (str[at] == '@' && str[at+1] == '{') {
reflog_len = (len-1) - (at+2);
len = at;
break;
}
}
}
/* Accept only unambiguous ref paths. */
if (len && ambiguous_path(str, len))
return -1;
if (!len && reflog_len) {
/* allow "@{...}" to mean the current branch reflog */
refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
} else if (reflog_len)
refs_found = dwim_log(str, len, sha1, &real_ref);
else
refs_found = dwim_ref(str, len, sha1, &real_ref);
if (!refs_found)
return -1;
if (warn_ambiguous_refs && refs_found > 1)
fprintf(stderr, warning, len, str);
if (reflog_len) {
int nth, i;
unsigned long at_time;
unsigned long co_time;
int co_tz, co_cnt;
/* Is it asking for N-th entry, or approxidate? */
for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
char ch = str[at+2+i];
if ('0' <= ch && ch <= '9')
nth = nth * 10 + ch - '0';
else
nth = -1;
}
if (0 <= nth)
at_time = 0;
else
at_time = approxidate(str + at + 2);
if (read_ref_at(real_ref, at_time, nth, sha1, NULL,
&co_time, &co_tz, &co_cnt)) {
if (at_time)
fprintf(stderr,
"warning: Log for '%.*s' only goes "
"back to %s.\n", len, str,
show_rfc2822_date(co_time, co_tz));
else
fprintf(stderr,
"warning: Log for '%.*s' only has "
"%d entries.\n", len, str, co_cnt);
}
}
free(real_ref);
return 0;
}
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) {
hashcpy(result, commit->object.sha1);
return 0;
}
p = commit->parents;
while (p) {
if (!--idx) {
hashcpy(result, p->item->object.sha1);
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;
hashcpy(sha1, commit->parents->item->object.sha1);
}
hashcpy(result, sha1);
return 0;
}
static int peel_onion(const char *name, int len, unsigned char *sha1)
{
unsigned char outer[20];
const char *sp;
unsigned int expected_type = 0;
struct object *o;
/*
* "ref^{type}" dereferences ref repeatedly until you cannot
* dereference anymore, or you get an object of given type,
* whichever comes first. "ref^{}" means just dereference
* tags until you get a non-tag. "ref^0" is a shorthand for
* "ref^{commit}". "commit^{tree}" could be used to find the
* top-level tree of the given commit.
*/
if (len < 4 || name[len-1] != '}')
return -1;
for (sp = name + len - 1; name <= sp; sp--) {
int ch = *sp;
if (ch == '{' && name < sp && sp[-1] == '^')
break;
}
if (sp <= name)
return -1;
sp++; /* beginning of type name, or closing brace for empty */
if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
expected_type = OBJ_COMMIT;
else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
expected_type = OBJ_TREE;
else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
expected_type = OBJ_BLOB;
else if (sp[0] == '}')
expected_type = OBJ_NONE;
else
return -1;
if (get_sha1_1(name, sp - name - 2, outer))
return -1;
o = parse_object(outer);
if (!o)
return -1;
if (!expected_type) {
o = deref_tag(o, name, sp - name - 2);
if (!o || (!o->parsed && !parse_object(o->sha1)))
return -1;
hashcpy(sha1, o->sha1);
}
else {
/* At this point, the syntax look correct, so
* if we do not get the needed object, we should
* barf.
*/
while (1) {
if (!o || (!o->parsed && !parse_object(o->sha1)))
return -1;
if (o->type == expected_type) {
hashcpy(sha1, o->sha1);
return 0;
}
if (o->type == OBJ_TAG)
o = ((struct tag*) o)->tagged;
else if (o->type == OBJ_COMMIT)
o = &(((struct commit *) o)->tree->object);
else
return error("%.*s: expected %s type, but the object dereferences to %s type",
len, name, typename(expected_type),
typename(o->type));
if (!o->parsed)
parse_object(o->sha1);
}
}
return 0;
}
static int get_describe_name(const char *name, int len, unsigned char *sha1)
{
const char *cp;
for (cp = name + len - 1; name + 2 <= cp; cp--) {
char ch = *cp;
if (hexval(ch) & ~0377) {
/* We must be looking at g in "SOMETHING-g"
* for it to be describe output.
*/
if (ch == 'g' && cp[-1] == '-') {
cp++;
len -= cp - name;
return get_short_sha1(cp, len, sha1, 1);
}
}
}
return -1;
}
static int get_sha1_1(const char *name, int len, unsigned char *sha1)
{
int ret, has_suffix;
const char *cp;
/* "name~3" is "name^^^",
* "name~" and "name~0" are name -- not "name^0"!
* "name^" is not "name^0"; it is "name^1".
*/
has_suffix = 0;
for (cp = name + len - 1; name <= cp; cp--) {
int ch = *cp;
if ('0' <= ch && ch <= '9')
continue;
if (ch == '~' || ch == '^')
has_suffix = ch;
break;
}
if (has_suffix) {
int num = 0;
int len1 = cp - name;
cp++;
while (cp < name + len)
num = num * 10 + *cp++ - '0';
if (has_suffix == '^') {
if (!num && len1 == len - 1)
num = 1;
return get_parent(name, len1, sha1, num);
}
/* else if (has_suffix == '~') -- goes without saying */
return get_nth_ancestor(name, len1, sha1, num);
}
ret = peel_onion(name, len, sha1);
if (!ret)
return 0;
ret = get_sha1_basic(name, len, sha1);
if (!ret)
return 0;
/* It could be describe output that is "SOMETHING-gXXXX" */
ret = get_describe_name(name, len, sha1);
if (!ret)
return 0;
return get_short_sha1(name, len, sha1, 0);
}
static int handle_one_ref(const char *path,
const unsigned char *sha1, int flag, void *cb_data)
{
struct commit_list **list = cb_data;
struct object *object = parse_object(sha1);
if (!object)
return 0;
if (object->type == OBJ_TAG)
object = deref_tag(object, path, strlen(path));
if (object->type != OBJ_COMMIT)
return 0;
insert_by_date((struct commit *)object, list);
return 0;
}
/*
* This interprets names like ':/Initial revision of "git"' by searching
* through history and returning the first commit whose message starts
* with the given string.
*
* For future extension, ':/!' is reserved. If you want to match a message
* beginning with a '!', you have to repeat the exclamation mark.
*/
#define ONELINE_SEEN (1u<<20)
int get_sha1_oneline(const char *prefix, unsigned char *sha1)
{
struct commit_list *list = NULL, *backup = NULL, *l;
struct commit *commit;
if (prefix[0] == '!') {
if (prefix[1] != '!')
die ("Invalid search pattern: %s", prefix);
prefix++;
}
if (!save_commit_buffer)
return error("Could not expand oneline-name.");
for_each_ref(handle_one_ref, &list);
for (l = list; l; l = l->next)
commit_list_insert(l->item, &backup);
while ((commit = pop_most_recent_commit(&list, ONELINE_SEEN))) {
char *p;
parse_object(commit->object.sha1);
if (!commit->buffer || !(p = strstr(commit->buffer, "\n\n")))
continue;
if (!prefixcmp(p + 2, prefix)) {
hashcpy(sha1, commit->object.sha1);
break;
}
}
free_commit_list(list);
for (l = backup; l; l = l->next)
clear_commit_marks(l->item, ONELINE_SEEN);
return commit == NULL;
}
/*
* 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)
{
int ret, bracket_depth;
unsigned unused;
int namelen = strlen(name);
const char *cp;
prepare_alt_odb();
ret = get_sha1_1(name, namelen, sha1);
if (!ret)
return ret;
/* sha1:path --> object name of path in ent sha1
* :path -> object name of path in index
* :[0-3]:path -> object name of path in index at stage
*/
if (name[0] == ':') {
int stage = 0;
struct cache_entry *ce;
int pos;
if (namelen > 2 && name[1] == '/')
return get_sha1_oneline(name + 2, sha1);
if (namelen < 3 ||
name[2] != ':' ||
name[1] < '0' || '3' < name[1])
cp = name + 1;
else {
stage = name[1] - '0';
cp = name + 3;
}
namelen = namelen - (cp - name);
if (!active_cache)
read_cache();
if (active_nr < 0)
return -1;
pos = cache_name_pos(cp, namelen);
if (pos < 0)
pos = -pos - 1;
while (pos < active_nr) {
ce = active_cache[pos];
if (ce_namelen(ce) != namelen ||
memcmp(ce->name, cp, namelen))
break;
if (ce_stage(ce) == stage) {
hashcpy(sha1, ce->sha1);
return 0;
}
pos++;
}
return -1;
}
for (cp = name, bracket_depth = 0; *cp; cp++) {
if (*cp == '{')
bracket_depth++;
else if (bracket_depth && *cp == '}')
bracket_depth--;
else if (!bracket_depth && *cp == ':')
break;
}
if (*cp == ':') {
unsigned char tree_sha1[20];
if (!get_sha1_1(name, cp-name, tree_sha1))
return get_tree_entry(tree_sha1, cp+1, sha1,
&unused);
}
return ret;
}