aboutsummaryrefslogtreecommitdiff
path: root/rev-parse.c
blob: 40707ac6ca7258878b47ed72074b3cf7364d3a56 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
/*
 * rev-parse.c
 *
 * Copyright (C) Linus Torvalds, 2005
 */
#include "cache.h"
#include "commit.h"

static int get_extended_sha1(char *name, unsigned char *sha1);

/*
 * Some arguments are relevant "revision" arguments,
 * others are about output format or other details.
 * This sorts it all out.
 */
static int is_rev_argument(const char *arg)
{
	static const char *rev_args[] = {
		"--max-count=",
		"--max-age=",
		"--min-age=",
		"--merge-order",
		NULL
	};
	const char **p = rev_args;

	for (;;) {
		const char *str = *p++;
		int len;
		if (!str)
			return 0;
		len = strlen(str);
		if (!strncmp(arg, str, len))
			return 1;
	}
}

static int get_parent(char *name, unsigned char *result, int idx)
{
	unsigned char sha1[20];
	int ret = get_extended_sha1(name, 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;
	p = commit->parents;
	while (p) {
		if (!--idx) {
			memcpy(result, p->item->object.sha1, 20);
			return 0;
		}
		p = p->next;
	}
	return -1;
}

/*
 * This is like "get_sha1()", except it allows "sha1 expressions",
 * notably "xyz^" for "parent of xyz"
 */
static int get_extended_sha1(char *name, unsigned char *sha1)
{
	int parent;
	int len = strlen(name);

	parent = 1;
	if (len > 2 && name[len-1] >= '1' && name[len-1] <= '9') {
		parent = name[len-1] - '0';
		len--;
	}
	if (len > 1 && name[len-1] == '^') {
		int ret;
		name[len-1] = 0;
		ret = get_parent(name, sha1, parent);
		name[len-1] = '^';
		if (!ret)
			return 0;
	}
	return get_sha1(name, sha1);
}

int main(int argc, char **argv)
{
	int i, as_is = 0, revs_only = 0, no_revs = 0;
	char *def = NULL;
	unsigned char sha1[20];

	for (i = 1; i < argc; i++) {
		char *arg = argv[i];
		char *dotdot;
	
		if (as_is) {
			printf("%s\n", arg);
			continue;
		}
		if (*arg == '-') {
			if (!strcmp(arg, "--")) {
				if (def) {
					printf("%s\n", def);
					def = NULL;
				}
				if (revs_only)
					break;
				as_is = 1;
			}
			if (!strcmp(arg, "--default")) {
				if (def)
					printf("%s\n", def);
				def = argv[i+1];
				i++;
				continue;
			}
			if (!strcmp(arg, "--revs-only")) {
				revs_only = 1;
				continue;
			}
			if (!strcmp(arg, "--no-revs")) {
				no_revs = 1;
				continue;
			}
			if (revs_only | no_revs) {
				if (is_rev_argument(arg) != revs_only)
					continue;
			}
			printf("%s\n", arg);
			continue;
		}
		dotdot = strstr(arg, "..");
		if (dotdot) {
			unsigned char end[20];
			char *n = dotdot+2;
			*dotdot = 0;
			if (!get_extended_sha1(arg, sha1)) {
				if (!*n)
					n = "HEAD";
				if (!get_extended_sha1(n, end)) {
					if (no_revs)
						continue;
					def = NULL;
					printf("%s\n", sha1_to_hex(end));
					printf("^%s\n", sha1_to_hex(sha1));
					continue;
				}
			}
			*dotdot = '.';
		}
		if (!get_extended_sha1(arg, sha1)) {
			if (no_revs)
				continue;
			def = NULL;
			printf("%s\n", sha1_to_hex(sha1));
			continue;
		}
		if (*arg == '^' && !get_extended_sha1(arg+1, sha1)) {
			if (no_revs)
				continue;
			def = NULL;
			printf("^%s\n", sha1_to_hex(sha1));
			continue;
		}
		if (def) {
			printf("%s\n", def);
			def = NULL;
		}
		if (revs_only)
			continue;
		printf("%s\n", arg);
	}
	if (def)
		printf("%s\n", def);
	return 0;
}