[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], 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);
}
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) {
0bc45890	94	unsigned char now[20], next[20];
9938af6a JH	95	nth_packed_object_sha1(p, first, now);
9938af6a JH	96	if (match_sha(len, match, now)) {
0bc45890 JH	97	if (nth_packed_object_sha1(p, first+1, next) \|\|
	98	!match_sha(len, match, next)) {
	99	/* unique within this pack */
	100	if (!found) {
	101	memcpy(found_sha1, now, 20);
	102	found++;
	103	}
	104	else if (memcmp(found_sha1, now, 20)) {
	105	found = 2;
	106	break;
	107	}
99a19b43	108	}
0bc45890 JH	109	else {
0bc45890 JH	110	/* not even unique within this pack */
99a19b43 JH	111	found = 2;
99a19b43 JH	112	break;
9938af6a JH	113	}
	114	}
	115	}
	116	}
99a19b43 JH	117	if (found == 1)
	118	memcpy(sha1, found_sha1, 20);
	119	return found;
	120	}
	121
	122	static int find_unique_short_object(int len, char *canonical,
	123	unsigned char res, unsigned char sha1)
	124	{
	125	int has_unpacked, has_packed;
	126	unsigned char unpacked_sha1[20], packed_sha1[20];
	127
	128	has_unpacked = find_short_object_filename(len, canonical, unpacked_sha1);
	129	has_packed = find_short_packed_object(len, res, packed_sha1);
	130	if (!has_unpacked && !has_packed)
	131	return -1;
	132	if (1 < has_unpacked \|\| 1 < has_packed)
0bc45890	133	return error("short SHA1 %.*s is ambiguous.", len, canonical);
99a19b43 JH	134	if (has_unpacked != has_packed) {
	135	memcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1), 20);
	136	return 0;
	137	}
	138	/* Both have unique ones -- do they match? */
	139	if (memcmp(packed_sha1, unpacked_sha1, 20))
5a82b4fb	140	return error("short SHA1 %.*s is ambiguous.", len, canonical);
99a19b43	141	memcpy(sha1, packed_sha1, 20);
9938af6a JH	142	return 0;
	143	}
	144
af61c6e0	145	static int get_short_sha1(const char name, int len, unsigned char sha1)
9938af6a JH	146	{
	147	int i;
	148	char canonical[40];
	149	unsigned char res[20];
	150
af61c6e0 LT	151	if (len < 4)
af61c6e0 LT	152	return -1;
9938af6a JH	153	memset(res, 0, 20);
9938af6a JH	154	memset(canonical, 'x', 40);
af61c6e0	155	for (i = 0; i < len ;i++) {
9938af6a JH	156	unsigned char c = name[i];
9938af6a JH	157	unsigned char val;
9938af6a JH	158	if (c >= '0' && c <= '9')
	159	val = c - '0';
	160	else if (c >= 'a' && c <= 'f')
	161	val = c - 'a' + 10;
	162	else if (c >= 'A' && c <='F') {
	163	val = c - 'A' + 10;
	164	c -= 'A' - 'a';
	165	}
	166	else
	167	return -1;
	168	canonical[i] = c;
	169	if (!(i & 1))
	170	val <<= 4;
	171	res[i >> 1] \|= val;
	172	}
99a19b43 JH	173
99a19b43 JH	174	return find_unique_short_object(i, canonical, res, sha1);
9938af6a JH	175	}
9938af6a JH	176
9938af6a JH	177	static int get_sha1_basic(const char str, int len, unsigned char sha1)
	178	{
	179	static const char *prefix[] = {
	180	"",
	181	"refs",
	182	"refs/tags",
	183	"refs/heads",
9938af6a JH	184	NULL
	185	};
	186	const char **p;
	187
3c3852e3	188	if (len == 40 && !get_sha1_hex(str, sha1))
9938af6a JH	189	return 0;
	190
	191	for (p = prefix; *p; p++) {
	192	char pathname = git_path("%s/%.s", *p, len, str);
ca8db142	193	if (!read_ref(pathname, sha1))
9938af6a JH	194	return 0;
	195	}
	196
	197	return -1;
	198	}
	199
	200	static int get_sha1_1(const char name, int len, unsigned char sha1);
	201
	202	static int get_parent(const char *name, int len,
	203	unsigned char *result, int idx)
	204	{
	205	unsigned char sha1[20];
	206	int ret = get_sha1_1(name, len, sha1);
	207	struct commit *commit;
	208	struct commit_list *p;
	209
	210	if (ret)
	211	return ret;
	212	commit = lookup_commit_reference(sha1);
	213	if (!commit)
	214	return -1;
	215	if (parse_commit(commit))
	216	return -1;
	217	if (!idx) {
	218	memcpy(result, commit->object.sha1, 20);
	219	return 0;
	220	}
	221	p = commit->parents;
	222	while (p) {
	223	if (!--idx) {
	224	memcpy(result, p->item->object.sha1, 20);
	225	return 0;
	226	}
	227	p = p->next;
	228	}
	229	return -1;
	230	}
	231
4f7599ac JH	232	static int get_nth_ancestor(const char *name, int len,
	233	unsigned char *result, int generation)
	234	{
	235	unsigned char sha1[20];
	236	int ret = get_sha1_1(name, len, sha1);
	237	if (ret)
	238	return ret;
	239
	240	while (generation--) {
	241	struct commit *commit = lookup_commit_reference(sha1);
	242
	243	if (!commit \|\| parse_commit(commit) \|\| !commit->parents)
	244	return -1;
	245	memcpy(sha1, commit->parents->item->object.sha1, 20);
	246	}
	247	memcpy(result, sha1, 20);
	248	return 0;
	249	}
	250
9938af6a JH	251	static int get_sha1_1(const char name, int len, unsigned char sha1)
	252	{
	253	int parent, ret;
4f7599ac	254	const char *cp;
9938af6a JH	255
	256	/* foo^[0-9] or foo^ (== foo^1); we do not do more than 9 parents. */
	257	if (len > 2 && name[len-2] == '^' &&
	258	name[len-1] >= '0' && name[len-1] <= '9') {
	259	parent = name[len-1] - '0';
	260	len -= 2;
	261	}
ef0bd2e6	262	else if (len > 1 && name[len-1] == '^') {
9938af6a	263	parent = 1;
ef0bd2e6 JS	264	len--;
ef0bd2e6 JS	265	} else
9938af6a JH	266	parent = -1;
9938af6a JH	267
02a4a32c LT	268	if (parent >= 0)
	269	return get_parent(name, len, sha1, parent);
	270
4f7599ac JH	271	/* "name~3" is "name^^^",
	272	* "name~12" is "name^^^^^^^^^^^^", and
	273	* "name~" and "name~0" are name -- not "name^0"!
	274	*/
	275	parent = 0;
	276	for (cp = name + len - 1; name <= cp; cp--) {
	277	int ch = *cp;
	278	if ('0' <= ch && ch <= '9')
	279	continue;
	280	if (ch != '~')
	281	parent = -1;
	282	break;
	283	}
	284	if (!parent && *cp == '~') {
	285	int len1 = cp - name;
	286	cp++;
	287	while (cp < name + len)
	288	parent = parent * 10 + *cp++ - '0';
	289	return get_nth_ancestor(name, len1, sha1, parent);
	290	}
	291
9938af6a JH	292	ret = get_sha1_basic(name, len, sha1);
	293	if (!ret)
	294	return 0;
af61c6e0	295	return get_short_sha1(name, len, sha1);
9938af6a JH	296	}
	297
	298	/*
	299	* This is like "get_sha1_basic()", except it allows "sha1 expressions",
	300	* notably "xyz^" for "parent of xyz"
	301	*/
	302	int get_sha1(const char name, unsigned char sha1)
	303	{
99a19b43	304	prepare_alt_odb();
9938af6a JH	305	return get_sha1_1(name, strlen(name), sha1);
9938af6a JH	306	}