[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)
{
	static char dirname[PATH_MAX];
	char hex[40];
	DIR *dir;
	int found;

	snprintf(dirname, sizeof(dirname), "%s/%.2s", get_object_directory(), name);
	dir = opendir(dirname);
	sprintf(hex, "%.2s", name);
	found = 0;
	if (dir) {
		struct dirent *de;
		while ((de = readdir(dir)) != NULL) {
			if (strlen(de->d_name) != 38)
				continue;
			if (memcmp(de->d_name, name + 2, len-2))
				continue;
			memcpy(hex + 2, de->d_name, 38);
			if (++found > 1)
				break;
		}
		closedir(dir);
	}
	if (found == 1)
		return get_sha1_hex(hex, sha1) == 0;
	return 0;
}

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;

	prepare_packed_git();
	for (p = packed_git; p; 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)) {
					memcpy(sha1, now, 20);
					return 1;
				}
			}
		}
	}
	return 0;
}

static int get_short_sha1(const char *name, unsigned char *sha1)
{
	int i;
	char canonical[40];
	unsigned char res[20];

	memset(res, 0, 20);
	memset(canonical, 'x', 40);
	for (i = 0;;i++) {
		unsigned char c = name[i];
		unsigned char val;
		if (!c || i > 40)
			break;
		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;
	}
	if (i < 4)
		return -1;
	if (find_short_object_filename(i, canonical, sha1))
		return 0;
	if (find_short_packed_object(i, res, sha1))
		return 0;
	return -1;
}

static int get_sha1_file(const char *path, unsigned char *result)
{
	char buffer[60];
	int fd = open(path, O_RDONLY);
	int len;

	if (fd < 0)
		return -1;
	len = read(fd, buffer, sizeof(buffer));
	close(fd);
	if (len < 40)
		return -1;
	return get_sha1_hex(buffer, result);
}

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 (!get_sha1_file(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, 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)
{
	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	{
	6	static char dirname[PATH_MAX];
	7	char hex[40];
	8	DIR *dir;
	9	int found;
	10
	11	snprintf(dirname, sizeof(dirname), "%s/%.2s", get_object_directory(), name);
	12	dir = opendir(dirname);
	13	sprintf(hex, "%.2s", name);
	14	found = 0;
	15	if (dir) {
	16	struct dirent *de;
	17	while ((de = readdir(dir)) != NULL) {
	18	if (strlen(de->d_name) != 38)
	19	continue;
	20	if (memcmp(de->d_name, name + 2, len-2))
	21	continue;
	22	memcpy(hex + 2, de->d_name, 38);
	23	if (++found > 1)
	24	break;
	25	}
	26	closedir(dir);
	27	}
	28	if (found == 1)
	29	return get_sha1_hex(hex, sha1) == 0;
	30	return 0;
	31	}
	32
	33	static int match_sha(unsigned len, const unsigned char a, const unsigned char b)
	34	{
	35	do {
	36	if (a != b)
	37	return 0;
	38	a++;
	39	b++;
	40	len -= 2;
	41	} while (len > 1);
	42	if (len)
	43	if ((a ^ b) & 0xf0)
	44	return 0;
	45	return 1;
	46	}
	47
	48	static int find_short_packed_object(int len, const unsigned char match, unsigned char sha1)
	49	{
	50	struct packed_git *p;
	51
	52	prepare_packed_git();
	53	for (p = packed_git; p; p = p->next) {
	54	unsigned num = num_packed_objects(p);
	55	unsigned first = 0, last = num;
	56	while (first < last) {
	57	unsigned mid = (first + last) / 2;
	58	unsigned char now[20];
	59	int cmp;
	60
	61	nth_packed_object_sha1(p, mid, now);
	62	cmp = memcmp(match, now, 20);
	63	if (!cmp) {
	64	first = mid;
65	break;
66	}
67	if (cmp > 0) {
68	first = mid+1;
69	continue;
70	}
71	last = mid;
72	}
73	if (first < num) {
74	unsigned char now[20], next[20];
75	nth_packed_object_sha1(p, first, now);
76	if (match_sha(len, match, now)) {
77	if (nth_packed_object_sha1(p, first+1, next) \|\| !match_sha(len, match, next)) {
78	memcpy(sha1, now, 20);
79	return 1;
80	}
81	}
82	}
83	}
84	return 0;
85	}
86
87	static int get_short_sha1(const char name, unsigned char sha1)
88	{
89	int i;
90	char canonical[40];
91	unsigned char res[20];
92
93	memset(res, 0, 20);
94	memset(canonical, 'x', 40);
95	for (i = 0;;i++) {
96	unsigned char c = name[i];
97	unsigned char val;
98	if (!c \|\| i > 40)
99	break;
100	if (c >= '0' && c <= '9')
101	val = c - '0';
102	else if (c >= 'a' && c <= 'f')
103	val = c - 'a' + 10;
104	else if (c >= 'A' && c <='F') {
105	val = c - 'A' + 10;
106	c -= 'A' - 'a';
107	}
108	else
109	return -1;
110	canonical[i] = c;
111	if (!(i & 1))
112	val <<= 4;
113	res[i >> 1] \|= val;
114	}
115	if (i < 4)
116	return -1;
117	if (find_short_object_filename(i, canonical, sha1))
118	return 0;
119	if (find_short_packed_object(i, res, sha1))
120	return 0;
121	return -1;
122	}
123
124	static int get_sha1_file(const char path, unsigned char result)
125	{
126	char buffer[60];
127	int fd = open(path, O_RDONLY);
128	int len;
129
130	if (fd < 0)
131	return -1;
132	len = read(fd, buffer, sizeof(buffer));
133	close(fd);
134	if (len < 40)
135	return -1;
136	return get_sha1_hex(buffer, result);
137	}
138
139	static int get_sha1_basic(const char str, int len, unsigned char sha1)
140	{
141	static const char *prefix[] = {
142	"",
143	"refs",
144	"refs/tags",
145	"refs/heads",
9938af6a JH	146	NULL
	147	};
	148	const char **p;
	149
3c3852e3	150	if (len == 40 && !get_sha1_hex(str, sha1))
9938af6a JH	151	return 0;
	152
	153	for (p = prefix; *p; p++) {
	154	char pathname = git_path("%s/%.s", *p, len, str);
	155	if (!get_sha1_file(pathname, sha1))
	156	return 0;
	157	}
	158
	159	return -1;
	160	}
	161
	162	static int get_sha1_1(const char name, int len, unsigned char sha1);
	163
	164	static int get_parent(const char *name, int len,
	165	unsigned char *result, int idx)
	166	{
	167	unsigned char sha1[20];
	168	int ret = get_sha1_1(name, len, sha1);
	169	struct commit *commit;
	170	struct commit_list *p;
	171
	172	if (ret)
	173	return ret;
	174	commit = lookup_commit_reference(sha1);
	175	if (!commit)
	176	return -1;
	177	if (parse_commit(commit))
	178	return -1;
	179	if (!idx) {
	180	memcpy(result, commit->object.sha1, 20);
	181	return 0;
	182	}
	183	p = commit->parents;
	184	while (p) {
	185	if (!--idx) {
	186	memcpy(result, p->item->object.sha1, 20);
	187	return 0;
	188	}
	189	p = p->next;
	190	}
	191	return -1;
	192	}
	193
4f7599ac JH	194	static int get_nth_ancestor(const char *name, int len,
	195	unsigned char *result, int generation)
	196	{
	197	unsigned char sha1[20];
	198	int ret = get_sha1_1(name, len, sha1);
	199	if (ret)
	200	return ret;
	201
	202	while (generation--) {
	203	struct commit *commit = lookup_commit_reference(sha1);
	204
	205	if (!commit \|\| parse_commit(commit) \|\| !commit->parents)
	206	return -1;
	207	memcpy(sha1, commit->parents->item->object.sha1, 20);
	208	}
	209	memcpy(result, sha1, 20);
	210	return 0;
	211	}
	212
9938af6a JH	213	static int get_sha1_1(const char name, int len, unsigned char sha1)
	214	{
	215	int parent, ret;
4f7599ac	216	const char *cp;
9938af6a JH	217
	218	/* foo^[0-9] or foo^ (== foo^1); we do not do more than 9 parents. */
	219	if (len > 2 && name[len-2] == '^' &&
	220	name[len-1] >= '0' && name[len-1] <= '9') {
	221	parent = name[len-1] - '0';
	222	len -= 2;
	223	}
ef0bd2e6	224	else if (len > 1 && name[len-1] == '^') {
9938af6a	225	parent = 1;
ef0bd2e6 JS	226	len--;
ef0bd2e6 JS	227	} else
9938af6a JH	228	parent = -1;
9938af6a JH	229
02a4a32c LT	230	if (parent >= 0)
	231	return get_parent(name, len, sha1, parent);
	232
4f7599ac JH	233	/* "name~3" is "name^^^",
	234	* "name~12" is "name^^^^^^^^^^^^", and
	235	* "name~" and "name~0" are name -- not "name^0"!
	236	*/
	237	parent = 0;
	238	for (cp = name + len - 1; name <= cp; cp--) {
	239	int ch = *cp;
	240	if ('0' <= ch && ch <= '9')
	241	continue;
	242	if (ch != '~')
	243	parent = -1;
	244	break;
	245	}
	246	if (!parent && *cp == '~') {
	247	int len1 = cp - name;
	248	cp++;
	249	while (cp < name + len)
	250	parent = parent * 10 + *cp++ - '0';
	251	return get_nth_ancestor(name, len1, sha1, parent);
	252	}
	253
9938af6a JH	254	ret = get_sha1_basic(name, len, sha1);
	255	if (!ret)
	256	return 0;
	257	return get_short_sha1(name, sha1);
	258	}
	259
	260	/*
	261	* This is like "get_sha1_basic()", except it allows "sha1 expressions",
	262	* notably "xyz^" for "parent of xyz"
	263	*/
	264	int get_sha1(const char name, unsigned char sha1)
	265	{
	266	return get_sha1_1(name, strlen(name), sha1);
	267	}