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
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
//! HTML tokenization into a simple event stream.
use super::style::decode_entities;
/// A simple tag-based HTML event
#[derive(Debug)]
pub(crate) enum HtmlEvent {
OpenTag {
name: String,
attrs: Vec<(String, String)>,
},
CloseTag(String),
Text(String),
}
/// Decode common HTML entities
pub(crate) fn tokenize_html(html: &str) -> Vec<HtmlEvent> {
let mut events = Vec::new();
let chars: Vec<char> = html.chars().collect();
let len = chars.len();
let mut i = 0;
while i < len {
if chars[i] == '<' {
i += 1;
if i >= len {
break;
}
// Comment <!-- ... -->
if i + 3 <= len
&& chars[i] == '!'
&& i + 1 < len
&& chars[i + 1] == '-'
&& i + 2 < len
&& chars[i + 2] == '-'
{
// skip to -->
i += 3;
while i + 2 < len
&& !(chars[i] == '-' && chars[i + 1] == '-' && chars[i + 2] == '>')
{
i += 1;
}
i += 3; // skip -->
continue;
}
// Doctype/other <!...>
if chars[i] == '!' {
while i < len && chars[i] != '>' {
i += 1;
}
i += 1;
continue;
}
// Closing tag </...>
if chars[i] == '/' {
i += 1;
// skip whitespace
while i < len
&& (chars[i] == ' ' || chars[i] == '\t' || chars[i] == '\n' || chars[i] == '\r')
{
i += 1;
}
let mut name = String::new();
while i < len && chars[i] != '>' {
if chars[i].is_alphanumeric()
|| chars[i] == '-'
|| chars[i] == ':'
|| chars[i] == '_'
|| chars[i] == '.'
{
name.push(chars[i]);
}
i += 1;
}
if i < len {
i += 1; // skip '>'
}
if !name.is_empty() {
events.push(HtmlEvent::CloseTag(name.to_lowercase()));
}
continue;
}
// Opening or self-closing tag
// Skip whitespace before tag name
while i < len
&& (chars[i] == ' ' || chars[i] == '\t' || chars[i] == '\n' || chars[i] == '\r')
{
i += 1;
}
let mut name = String::new();
while i < len
&& (chars[i].is_alphanumeric()
|| chars[i] == '-'
|| chars[i] == ':'
|| chars[i] == '_'
|| chars[i] == '.')
{
name.push(chars[i]);
i += 1;
}
let tag_name = name.to_lowercase();
// Parse attributes
let mut attrs: Vec<(String, String)> = Vec::new();
while i < len && chars[i] != '>' {
// Skip whitespace
while i < len
&& (chars[i] == ' ' || chars[i] == '\t' || chars[i] == '\n' || chars[i] == '\r')
{
i += 1;
}
if i >= len || chars[i] == '>' {
break;
}
if chars[i] == '/' {
i += 1;
continue;
}
// Read attribute name
let mut attr_name = String::new();
while i < len
&& chars[i] != '='
&& chars[i] != '>'
&& chars[i] != ' '
&& chars[i] != '\t'
&& chars[i] != '\n'
&& chars[i] != '\r'
&& chars[i] != '/'
{
attr_name.push(chars[i]);
i += 1;
}
// Skip whitespace around =
while i < len
&& (chars[i] == ' ' || chars[i] == '\t' || chars[i] == '\n' || chars[i] == '\r')
{
i += 1;
}
let mut attr_value = String::new();
if i < len && chars[i] == '=' {
i += 1;
// Skip whitespace after =
while i < len
&& (chars[i] == ' '
|| chars[i] == '\t'
|| chars[i] == '\n'
|| chars[i] == '\r')
{
i += 1;
}
if i < len && (chars[i] == '"' || chars[i] == '\'') {
let quote = chars[i];
i += 1;
while i < len && chars[i] != quote {
attr_value.push(chars[i]);
i += 1;
}
if i < len {
i += 1; // skip closing quote
}
} else {
// unquoted value
while i < len
&& chars[i] != '>'
&& chars[i] != ' '
&& chars[i] != '\t'
&& chars[i] != '\n'
&& chars[i] != '\r'
&& chars[i] != '/'
{
attr_value.push(chars[i]);
i += 1;
}
}
}
attrs.push((attr_name.to_lowercase(), decode_entities(&attr_value)));
}
if i < len {
i += 1; // skip '>'
}
if !tag_name.is_empty() {
events.push(HtmlEvent::OpenTag {
name: tag_name,
attrs,
});
}
} else {
// Text content
let mut text = String::new();
while i < len && chars[i] != '<' {
text.push(chars[i]);
i += 1;
}
let trimmed = text.trim();
if !trimmed.is_empty() {
events.push(HtmlEvent::Text(decode_entities(&text)));
}
}
}
events
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_tokenize_basic() {
let events = tokenize_html("<h1>Hello</h1>");
assert_eq!(events.len(), 3);
match &events[0] {
HtmlEvent::OpenTag { name, .. } => assert_eq!(name, "h1"),
_ => panic!("expected OpenTag"),
}
match &events[1] {
HtmlEvent::Text(t) => assert_eq!(t.trim(), "Hello"),
_ => panic!("expected Text"),
}
match &events[2] {
HtmlEvent::CloseTag(n) => assert_eq!(n, "h1"),
_ => panic!("expected CloseTag"),
}
}
#[test]
fn test_attrs_with_single_quotes() {
let events = tokenize_html(r#"<img src='pic.jpg' alt='hello'>"#);
assert_eq!(events.len(), 1);
match &events[0] {
HtmlEvent::OpenTag { name, attrs } => {
assert_eq!(name, "img");
assert_eq!(
attrs
.iter()
.find(|(k, _)| k == "src")
.map(|(_, v)| v.as_str()),
Some("pic.jpg")
);
assert_eq!(
attrs
.iter()
.find(|(k, _)| k == "alt")
.map(|(_, v)| v.as_str()),
Some("hello")
);
}
_ => panic!("expected OpenTag"),
}
}
#[test]
fn test_tokenizer_complex() {
let events = tokenize_html(r#"<div class="main"><h1 id="title">Hello</h1></div>"#);
assert_eq!(events.len(), 5);
match &events[0] {
HtmlEvent::OpenTag { name, attrs } => {
assert_eq!(name, "div");
assert_eq!(attrs[0].0, "class");
assert_eq!(attrs[0].1, "main");
}
_ => panic!("expected OpenTag div"),
}
}
#[test]
fn test_self_closing_void_tags() {
let events = tokenize_html(r#"<br><hr><img src="x.jpg">"#);
assert_eq!(events.len(), 3);
for event in &events {
match event {
HtmlEvent::OpenTag { name, .. } => {
assert!(["br", "hr", "img"].contains(&name.as_str()));
}
_ => panic!("expected OpenTag for void elements"),
}
}
}
#[test]
fn test_comments_skipped() {
let events = tokenize_html(r#"<h1>A</h1><!-- comment --><p>B</p>"#);
// Events: OpenTag(h1), Text(A), CloseTag(h1), OpenTag(p), Text(B), CloseTag(p)
assert_eq!(events.len(), 6);
match &events[3] {
HtmlEvent::OpenTag { name, .. } => assert_eq!(name, "p"),
_ => panic!("expected p"),
}
}
#[test]
fn test_doctype_skipped() {
let events = tokenize_html("<!DOCTYPE html><h1>Title</h1>");
assert_eq!(events.len(), 3);
match &events[0] {
HtmlEvent::OpenTag { name, .. } => assert_eq!(name, "h1"),
_ => panic!("expected h1"),
}
}
#[test]
fn test_multiple_attributes() {
let events = tokenize_html(r#"<a href="https://x.com" class="link" id="main">text</a>"#);
assert_eq!(events.len(), 3);
match &events[0] {
HtmlEvent::OpenTag { name, attrs } => {
assert_eq!(name, "a");
assert_eq!(attrs.len(), 3);
}
_ => panic!("expected OpenTag"),
}
}
}