1 /*
2  * Copyright (c) 2022 Omar Polo <op@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <ctype.h>
18 #include <stdarg.h>
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <string.h>
22 
23 #include "tmpl.h"
24 
25 int
26 tp_write(struct template *tp, const char *str, size_t len)
27 {
28 	size_t	 avail;
29 
30 	while (len > 0) {
31 		avail = tp->tp_cap - tp->tp_len;
32 		if (avail == 0) {
33 			if (template_flush(tp) == -1)
34 				return (-1);
35 			avail = tp->tp_cap;
36 		}
37 
38 		if (len < avail)
39 			avail = len;
40 
41 		memcpy(tp->tp_buf + tp->tp_len, str, avail);
42 		tp->tp_len += avail;
43 		str += avail;
44 		len -= avail;
45 	}
46 
47 	return (0);
48 }
49 
50 int
51 tp_writes(struct template *tp, const char *str)
52 {
53 	return (tp_write(tp, str, strlen(str)));
54 }
55 
56 int
57 tp_writef(struct template *tp, const char *fmt, ...)
58 {
59 	va_list	 ap;
60 	char	*str;
61 	int	 r;
62 
63 	va_start(ap, fmt);
64 	r = vasprintf(&str, fmt, ap);
65 	va_end(ap);
66 	if (r == -1)
67 		return (-1);
68 	r = tp_write(tp, str, r);
69 	free(str);
70 	return (r);
71 }
72 
73 int
74 tp_urlescape(struct template *tp, const char *str)
75 {
76 	int	 r;
77 	char	 tmp[4];
78 
79 	if (str == NULL)
80 		return (0);
81 
82 	for (; *str; ++str) {
83 		if (iscntrl((unsigned char)*str) ||
84 		    isspace((unsigned char)*str) ||
85 		    *str == '\'' || *str == '"' || *str == '\\') {
86 			r = snprintf(tmp, sizeof(tmp), "%%%2X", *str);
87 			if (r < 0  || (size_t)r >= sizeof(tmp))
88 				return (0);
89 			if (tp_write(tp, tmp, r) == -1)
90 				return (-1);
91 		} else {
92 			if (tp_write(tp, str, 1) == -1)
93 				return (-1);
94 		}
95 	}
96 
97 	return (0);
98 }
99 
100 static inline int
101 htmlescape(struct template *tp, char c)
102 {
103 	switch (c) {
104 	case '<':
105 		return tp_write(tp, "&lt;", 4);
106 	case '>':
107 		return tp_write(tp, "&gt;", 4);
108 	case '&':
109 		return tp_write(tp, "&amp;", 5);
110 	case '"':
111 		return tp_write(tp, "&quot;", 6);
112 	case '\'':
113 		return tp_write(tp, "&apos;", 6);
114 	default:
115 		return tp_write(tp, &c, 1);
116 	}
117 }
118 
119 int
120 tp_htmlescape(struct template *tp, const char *str)
121 {
122 	if (str == NULL)
123 		return (0);
124 
125 	for (; *str; ++str) {
126 		if (htmlescape(tp, *str) == -1)
127 			return (-1);
128 	}
129 
130 	return (0);
131 }
132 
133 int
134 tp_write_htmlescape(struct template *tp, const char *str, size_t len)
135 {
136 	size_t i;
137 
138 	for (i = 0; i < len; ++i) {
139 		if (htmlescape(tp, str[i]) == -1)
140 			return (-1);
141 	}
142 
143 	return (0);
144 }
145 
146 struct template *
147 template(void *arg, tmpl_write writefn, char *buf, size_t siz)
148 {
149 	struct template *tp;
150 
151 	if ((tp = calloc(1, sizeof(*tp))) == NULL)
152 		return (NULL);
153 
154 	tp->tp_arg = arg;
155 	tp->tp_write = writefn;
156 	tp->tp_buf = buf;
157 	tp->tp_cap = siz;
158 
159 	return (tp);
160 }
161 
162 int
163 template_flush(struct template *tp)
164 {
165 	if (tp->tp_len == 0)
166 		return (0);
167 
168 	if (tp->tp_write(tp->tp_arg, tp->tp_buf, tp->tp_len) == -1)
169 		return (-1);
170 	tp->tp_len = 0;
171 	return (0);
172 }
173 
174 void
175 template_free(struct template *tp)
176 {
177 	free(tp->tp_tmp);
178 	free(tp);
179 }