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
|
//! Provides the [`Reader`] trait (and implementations) used by the tokenizer.
use std::convert::Infallible;
use std::io::{self, BufRead, BufReader, Read};
/// An object that provides characters to the tokenizer.
///
/// Patches are welcome for providing an efficient implementation over async streams,
/// iterators, files, etc, as long as any dependencies come behind featureflags.
pub trait Reader {
/// The error returned by this reader.
type Error: std::error::Error;
/// Return a new character from the input stream.
///
/// The input stream does **not** have to be preprocessed in any way, it can contain standalone
/// surrogates and have inconsistent newlines.
fn read_char(&mut self) -> Result<Option<char>, Self::Error>;
/// Attempt to read an entire string at once, either case-insensitively or not.
///
/// `case_sensitive=false` means that characters of the input stream should be compared while
/// ignoring ASCII-casing.
///
/// It can be assumed that this function is never called with a string that contains `\r` or
/// `\n`.
///
/// If the next characters equal to `s`, this function consumes the respective characters from
/// the input stream and returns `true`. If not, it does nothing and returns `false`.
fn try_read_string(&mut self, s: &str, case_sensitive: bool) -> Result<bool, Self::Error>;
}
/// An object that can be converted into a [`Reader`].
///
/// For example, any utf8-string can be converted into a `StringReader`.
// TODO: , such that [give concrete examples of not-yet-implemented parser API] work.
pub trait IntoReader<'a> {
/// The reader type into which this type should be converted.
type Reader: Reader + 'a;
/// Convert self into some sort of reader.
fn into_reader(self) -> Self::Reader;
}
impl<'a, R: 'a + Reader> IntoReader<'a> for R {
type Reader = Self;
fn into_reader(self) -> Self::Reader {
self
}
}
/// A helper struct to seek forwards and backwards in strings. Used by the tokenizer to read HTML
/// from strings.
pub struct StringReader<'a> {
input: &'a str,
cursor: std::str::Chars<'a>,
pos: usize,
}
impl<'a> StringReader<'a> {
fn new(input: &'a str) -> Self {
let cursor = input.chars();
StringReader {
input,
cursor,
pos: 0,
}
}
}
impl<'a> Reader for StringReader<'a> {
type Error = Infallible;
fn read_char(&mut self) -> Result<Option<char>, Self::Error> {
let c = match self.cursor.next() {
Some(c) => c,
None => return Ok(None),
};
self.pos += c.len_utf8();
Ok(Some(c))
}
fn try_read_string(&mut self, s1: &str, case_sensitive: bool) -> Result<bool, Self::Error> {
// we do not need to call validate_char here because `s` hopefully does not contain invalid
// characters
if let Some(s2) = self.input.get(self.pos..self.pos + s1.len()) {
if s1 == s2 || (!case_sensitive && s1.eq_ignore_ascii_case(s2)) {
self.pos += s1.len();
self.cursor = self.input[self.pos..].chars();
return Ok(true);
}
}
Ok(false)
}
}
impl<'a> IntoReader<'a> for &'a str {
type Reader = StringReader<'a>;
fn into_reader(self) -> Self::Reader {
StringReader::new(self)
}
}
impl<'a> IntoReader<'a> for &'a String {
type Reader = StringReader<'a>;
fn into_reader(self) -> Self::Reader {
StringReader::new(self.as_str())
}
}
/// A [`BufReadReader`] can be used to construct a tokenizer from any type that implements
/// `BufRead`.
pub struct BufReadReader<R: BufRead> {
line: String,
line_pos: usize,
reader: R,
}
impl<R: BufRead> BufReadReader<R> {
/// Construct a new `BufReadReader` from any type that implements `BufRead`.
pub fn new(reader: R) -> Self {
BufReadReader {
line: String::new(),
line_pos: 0,
reader,
}
}
#[inline]
fn get_remaining_line(&mut self) -> Result<&str, io::Error> {
if self.line_pos < self.line.len() {
return Ok(&self.line[self.line_pos..]);
}
self.line.clear();
self.line_pos = 0;
self.reader.read_line(&mut self.line)?;
Ok(&self.line)
}
}
impl<R: BufRead> Reader for BufReadReader<R> {
type Error = io::Error;
fn read_char(&mut self) -> Result<Option<char>, Self::Error> {
let rv = self.get_remaining_line()?.chars().next();
self.line_pos += rv.map(char::len_utf8).unwrap_or(1);
Ok(rv)
}
fn try_read_string(&mut self, s1: &str, case_sensitive: bool) -> Result<bool, Self::Error> {
debug_assert!(!s1.contains('\r'));
debug_assert!(!s1.contains('\n'));
if let Some(s2) = self.get_remaining_line()?.get(..s1.len()) {
if s1 == s2 || (!case_sensitive && s1.eq_ignore_ascii_case(s2)) {
self.line_pos += s1.len();
return Ok(true);
}
}
Ok(false)
}
}
impl<'a, R: Read + 'a> IntoReader<'a> for BufReader<R> {
type Reader = BufReadReader<BufReader<R>>;
fn into_reader(self) -> Self::Reader {
BufReadReader::new(self)
}
}
|
