summaryrefslogtreecommitdiff
path: root/url.c
blob: 3e06fd34c46a00b41f4843ea87a151314ce0789c (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
#include "cache.h"
#include "url.h"

int is_urlschemechar(int first_flag, int ch)
{
	/*
	 * The set of valid URL schemes, as per STD66 (RFC3986) is
	 * '[A-Za-z][A-Za-z0-9+.-]*'. But use sightly looser check
	 * of '[A-Za-z0-9][A-Za-z0-9+.-]*' because earlier version
	 * of check used '[A-Za-z0-9]+' so not to break any remote
	 * helpers.
	 */
	int alphanumeric, special;
	alphanumeric = ch > 0 && isalnum(ch);
	special = ch == '+' || ch == '-' || ch == '.';
	return alphanumeric || (!first_flag && special);
}

int is_url(const char *url)
{
	const char *url2, *first_slash;

	if (!url)
		return 0;
	url2 = url;
	first_slash = strchr(url, '/');

	/* Input with no slash at all or slash first can't be URL. */
	if (!first_slash || first_slash == url)
		return 0;
	/* Character before must be : and next must be /. */
	if (first_slash[-1] != ':' || first_slash[1] != '/')
		return 0;
	/* There must be something before the :// */
	if (first_slash == url + 1)
		return 0;
	/*
	 * Check all characters up to first slash - 1. Only alphanum
	 * is allowed.
	 */
	url2 = url;
	while (url2 < first_slash - 1) {
		if (!is_urlschemechar(url2 == url, (unsigned char)*url2))
			return 0;
		url2++;
	}

	/* Valid enough. */
	return 1;
}

static int url_decode_char(const char *q)
{
	int i;
	unsigned char val = 0;
	for (i = 0; i < 2; i++) {
		unsigned char c = *q++;
		val <<= 4;
		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;
		else
			return -1;
	}
	return val;
}

static char *url_decode_internal(const char **query, const char *stop_at,
				 struct strbuf *out, int decode_plus)
{
	const char *q = *query;

	do {
		unsigned char c = *q;

		if (!c)
			break;
		if (stop_at && strchr(stop_at, c)) {
			q++;
			break;
		}

		if (c == '%') {
			int val = url_decode_char(q + 1);
			if (0 <= val) {
				strbuf_addch(out, val);
				q += 3;
				continue;
			}
		}

		if (decode_plus && c == '+')
			strbuf_addch(out, ' ');
		else
			strbuf_addch(out, c);
		q++;
	} while (1);
	*query = q;
	return strbuf_detach(out, NULL);
}

char *url_decode(const char *url)
{
	struct strbuf out = STRBUF_INIT;
	const char *colon = strchr(url, ':');

	/* Skip protocol part if present */
	if (colon && url < colon) {
		strbuf_add(&out, url, colon - url);
		url = colon;
	}
	return url_decode_internal(&url, NULL, &out, 0);
}

char *url_decode_parameter_name(const char **query)
{
	struct strbuf out = STRBUF_INIT;
	return url_decode_internal(query, "&=", &out, 1);
}

char *url_decode_parameter_value(const char **query)
{
	struct strbuf out = STRBUF_INIT;
	return url_decode_internal(query, "&", &out, 1);
}

void end_url_with_slash(struct strbuf *buf, const char *url)
{
	strbuf_addstr(buf, url);
	if (buf->len && buf->buf[buf->len - 1] != '/')
		strbuf_addstr(buf, "/");
}

void str_end_url_with_slash(const char *url, char **dest) {
	struct strbuf buf = STRBUF_INIT;
	end_url_with_slash(&buf, url);
	free(*dest);
	*dest = strbuf_detach(&buf, NULL);
}