[thirdparty/git.git] / sha1_name.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];
			nth_packed_object_sha1(p, first, now);
			if (match_sha(len, match, now)) {
				if (!found) {
					memcpy(found_sha1, now, 20);
					found++;
				}
				else if (memcmp(found_sha1, now, 20)) {
					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 -1;
	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);
}
Commit	Line	Data
9938af6a JH	1	#include "cache.h"
	2	#include "commit.h"
	3
	4	static int find_short_object_filename(int len, const char name, unsigned char sha1)
	5	{
99a19b43	6	struct alternate_object_database *alt;
9938af6a	7	char hex[40];
99a19b43 JH	8	int found = 0;
	9	static struct alternate_object_database *fakeent;
	10
	11	if (!fakeent) {
	12	const char *objdir = get_object_directory();
	13	int objdir_len = strlen(objdir);
	14	int entlen = objdir_len + 43;
	15	fakeent = xmalloc(sizeof(*fakeent) + entlen);
	16	memcpy(fakeent->base, objdir, objdir_len);
	17	fakeent->name = fakeent->base + objdir_len + 1;
	18	fakeent->name[-1] = '/';
	19	}
	20	fakeent->next = alt_odb_list;
9938af6a	21
9938af6a	22	sprintf(hex, "%.2s", name);
99a19b43	23	for (alt = fakeent; alt && found < 2; alt = alt->next) {
9938af6a	24	struct dirent *de;
99a19b43 JH	25	DIR *dir;
	26	sprintf(alt->name, "%.2s/", name);
	27	dir = opendir(alt->base);
	28	if (!dir)
	29	continue;
9938af6a JH	30	while ((de = readdir(dir)) != NULL) {
	31	if (strlen(de->d_name) != 38)
	32	continue;
99a19b43	33	if (memcmp(de->d_name, name + 2, len - 2))
9938af6a	34	continue;
99a19b43 JH	35	if (!found) {
	36	memcpy(hex + 2, de->d_name, 38);
	37	found++;
	38	}
	39	else if (memcmp(hex + 2, de->d_name, 38)) {
	40	found = 2;
9938af6a	41	break;
99a19b43	42	}
9938af6a JH	43	}
	44	closedir(dir);
	45	}
	46	if (found == 1)
	47	return get_sha1_hex(hex, sha1) == 0;
99a19b43	48	return found;
9938af6a JH	49	}
	50
	51	static int match_sha(unsigned len, const unsigned char a, const unsigned char b)
	52	{
	53	do {
	54	if (a != b)
	55	return 0;
	56	a++;
	57	b++;
	58	len -= 2;
	59	} while (len > 1);
	60	if (len)
	61	if ((a ^ b) & 0xf0)
	62	return 0;
	63	return 1;
	64	}
	65
	66	static int find_short_packed_object(int len, const unsigned char match, unsigned char sha1)
	67	{
	68	struct packed_git *p;
99a19b43 JH	69	unsigned char found_sha1[20];
99a19b43 JH	70	int found = 0;
9938af6a JH	71
9938af6a JH	72	prepare_packed_git();
99a19b43	73	for (p = packed_git; p && found < 2; p = p->next) {
9938af6a JH	74	unsigned num = num_packed_objects(p);
	75	unsigned first = 0, last = num;
	76	while (first < last) {
	77	unsigned mid = (first + last) / 2;
	78	unsigned char now[20];
	79	int cmp;
	80
	81	nth_packed_object_sha1(p, mid, now);
	82	cmp = memcmp(match, now, 20);
	83	if (!cmp) {
	84	first = mid;
	85	break;
	86	}
	87	if (cmp > 0) {
	88	first = mid+1;
	89	continue;
	90	}
	91	last = mid;
	92	}
	93	if (first < num) {
99a19b43	94	unsigned char now[20];
9938af6a JH	95	nth_packed_object_sha1(p, first, now);
9938af6a JH	96	if (match_sha(len, match, now)) {
99a19b43 JH	97	if (!found) {
	98	memcpy(found_sha1, now, 20);
	99	found++;
	100	}
	101	else if (memcmp(found_sha1, now, 20)) {
	102	found = 2;
	103	break;
9938af6a JH	104	}
	105	}
	106	}
	107	}
99a19b43 JH	108	if (found == 1)
	109	memcpy(sha1, found_sha1, 20);
	110	return found;
	111	}
	112
	113	static int find_unique_short_object(int len, char *canonical,
	114	unsigned char res, unsigned char sha1)
	115	{
	116	int has_unpacked, has_packed;
	117	unsigned char unpacked_sha1[20], packed_sha1[20];
	118
	119	has_unpacked = find_short_object_filename(len, canonical, unpacked_sha1);
	120	has_packed = find_short_packed_object(len, res, packed_sha1);
	121	if (!has_unpacked && !has_packed)
	122	return -1;
	123	if (1 < has_unpacked \|\| 1 < has_packed)
	124	return -1;
	125	if (has_unpacked != has_packed) {
	126	memcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1), 20);
	127	return 0;
	128	}
	129	/* Both have unique ones -- do they match? */
	130	if (memcmp(packed_sha1, unpacked_sha1, 20))
5a82b4fb	131	return error("short SHA1 %.*s is ambiguous.", len, canonical);
99a19b43	132	memcpy(sha1, packed_sha1, 20);
9938af6a JH	133	return 0;
	134	}
	135
af61c6e0	136	static int get_short_sha1(const char name, int len, unsigned char sha1)
9938af6a JH	137	{
	138	int i;
	139	char canonical[40];
	140	unsigned char res[20];
	141
af61c6e0 LT	142	if (len < 4)
af61c6e0 LT	143	return -1;
9938af6a JH	144	memset(res, 0, 20);
9938af6a JH	145	memset(canonical, 'x', 40);
af61c6e0	146	for (i = 0; i < len ;i++) {
9938af6a JH	147	unsigned char c = name[i];
9938af6a JH	148	unsigned char val;
9938af6a JH	149	if (c >= '0' && c <= '9')
	150	val = c - '0';
	151	else if (c >= 'a' && c <= 'f')
	152	val = c - 'a' + 10;
	153	else if (c >= 'A' && c <='F') {
	154	val = c - 'A' + 10;
	155	c -= 'A' - 'a';
	156	}
	157	else
	158	return -1;
	159	canonical[i] = c;
	160	if (!(i & 1))
	161	val <<= 4;
	162	res[i >> 1] \|= val;
	163	}
99a19b43 JH	164
99a19b43 JH	165	return find_unique_short_object(i, canonical, res, sha1);
9938af6a JH	166	}
9938af6a JH	167
9938af6a JH	168	static int get_sha1_basic(const char str, int len, unsigned char sha1)
	169	{
	170	static const char *prefix[] = {
	171	"",
	172	"refs",
	173	"refs/tags",
	174	"refs/heads",
9938af6a JH	175	NULL
	176	};
	177	const char **p;
	178
3c3852e3	179	if (len == 40 && !get_sha1_hex(str, sha1))
9938af6a JH	180	return 0;
	181
	182	for (p = prefix; *p; p++) {
	183	char pathname = git_path("%s/%.s", *p, len, str);
ca8db142	184	if (!read_ref(pathname, sha1))
9938af6a JH	185	return 0;
	186	}
	187
	188	return -1;
	189	}
	190
	191	static int get_sha1_1(const char name, int len, unsigned char sha1);
	192
	193	static int get_parent(const char *name, int len,
	194	unsigned char *result, int idx)
	195	{
	196	unsigned char sha1[20];
	197	int ret = get_sha1_1(name, len, sha1);
	198	struct commit *commit;
	199	struct commit_list *p;
	200
	201	if (ret)
	202	return ret;
	203	commit = lookup_commit_reference(sha1);
	204	if (!commit)
	205	return -1;
	206	if (parse_commit(commit))
	207	return -1;
	208	if (!idx) {
	209	memcpy(result, commit->object.sha1, 20);
	210	return 0;
	211	}
	212	p = commit->parents;
	213	while (p) {
	214	if (!--idx) {
	215	memcpy(result, p->item->object.sha1, 20);
	216	return 0;
	217	}
	218	p = p->next;
	219	}
	220	return -1;
	221	}
	222
4f7599ac JH	223	static int get_nth_ancestor(const char *name, int len,
	224	unsigned char *result, int generation)
	225	{
	226	unsigned char sha1[20];
	227	int ret = get_sha1_1(name, len, sha1);
	228	if (ret)
	229	return ret;
	230
	231	while (generation--) {
	232	struct commit *commit = lookup_commit_reference(sha1);
	233
	234	if (!commit \|\| parse_commit(commit) \|\| !commit->parents)
	235	return -1;
	236	memcpy(sha1, commit->parents->item->object.sha1, 20);
	237	}
	238	memcpy(result, sha1, 20);
	239	return 0;
	240	}
	241
9938af6a JH	242	static int get_sha1_1(const char name, int len, unsigned char sha1)
	243	{
	244	int parent, ret;
4f7599ac	245	const char *cp;
9938af6a JH	246
	247	/* foo^[0-9] or foo^ (== foo^1); we do not do more than 9 parents. */
	248	if (len > 2 && name[len-2] == '^' &&
	249	name[len-1] >= '0' && name[len-1] <= '9') {
	250	parent = name[len-1] - '0';
	251	len -= 2;
	252	}
ef0bd2e6	253	else if (len > 1 && name[len-1] == '^') {
9938af6a	254	parent = 1;
ef0bd2e6 JS	255	len--;
ef0bd2e6 JS	256	} else
9938af6a JH	257	parent = -1;
9938af6a JH	258
02a4a32c LT	259	if (parent >= 0)
	260	return get_parent(name, len, sha1, parent);
	261
4f7599ac JH	262	/* "name~3" is "name^^^",
	263	* "name~12" is "name^^^^^^^^^^^^", and
	264	* "name~" and "name~0" are name -- not "name^0"!
	265	*/
	266	parent = 0;
	267	for (cp = name + len - 1; name <= cp; cp--) {
	268	int ch = *cp;
	269	if ('0' <= ch && ch <= '9')
	270	continue;
	271	if (ch != '~')
	272	parent = -1;
	273	break;
	274	}
	275	if (!parent && *cp == '~') {
	276	int len1 = cp - name;
	277	cp++;
	278	while (cp < name + len)
	279	parent = parent * 10 + *cp++ - '0';
	280	return get_nth_ancestor(name, len1, sha1, parent);
	281	}
	282
9938af6a JH	283	ret = get_sha1_basic(name, len, sha1);
	284	if (!ret)
	285	return 0;
af61c6e0	286	return get_short_sha1(name, len, sha1);
9938af6a JH	287	}
	288
	289	/*
	290	* This is like "get_sha1_basic()", except it allows "sha1 expressions",
	291	* notably "xyz^" for "parent of xyz"
	292	*/
	293	int get_sha1(const char name, unsigned char sha1)
	294	{
99a19b43	295	prepare_alt_odb();
9938af6a JH	296	return get_sha1_1(name, strlen(name), sha1);
9938af6a JH	297	}