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
use super::*;
use std::{
collections::HashMap,
hash::{BuildHasher, Hasher},
mem::replace,
path::PathBuf,
};
/// A type representing a single line of a [`Source`].
#[derive(Clone, Debug, Hash, PartialEq, Eq)]
pub struct Line {
offset: usize,
len: usize,
chars: String,
}
impl Line {
/// Get the offset of this line in the original [`Source`] (i.e: the number of characters that precede it).
pub fn offset(&self) -> usize {
self.offset
}
/// Get the character length of this line.
pub fn len(&self) -> usize {
self.len
}
/// Get the offset span of this line in the original [`Source`].
pub fn span(&self) -> Range<usize> {
self.offset..self.offset + self.len
}
/// Return an iterator over the characters in the line, excluding trailing whitespace.
pub fn chars(&self) -> impl Iterator<Item = char> + '_ {
self.chars.chars()
}
/// Get the view of this line in the original [`Source`].
pub fn view(&self) -> &str {
&self.chars
}
}
/// A type representing a single source that may be referred to by [`Span`]s.
///
/// In most cases, a source is a single input file.
#[derive(Clone, Debug, Hash, PartialEq, Eq)]
pub struct Source {
file_name: String,
lines: Vec<Line>,
len: usize,
}
impl<S: AsRef<str>> From<S> for Source {
/// Generate a [`Source`] from the given [`str`].
///
/// Note that this function can be expensive for long strings. Use an implementor of [`Cache`] where possible.
fn from(s: S) -> Self {
let mut offset = 0;
// (Last line, last line ends with CR)
let mut last_line: Option<(Line, bool)> = None;
let mut lines: Vec<Line> = s
.as_ref()
.split_inclusive([
'\r', // Carriage return
'\n', // Line feed
'\x0B', // Vertical tab
'\x0C', // Form feed
'\u{0085}', // Next line
'\u{2028}', // Line separator
'\u{2029}', // Paragraph separator
])
.flat_map(|line| {
// Returns last line and set `last_line` to current `line`
// A hack that makes `flat_map` deals with consecutive lines
if let Some((last, ends_with_cr)) = last_line.as_mut() {
if *ends_with_cr && line == "\n" {
last.len += 1;
offset += 1;
return replace(&mut last_line, None).map(|(l, _)| l);
}
}
let len = line.chars().count();
let ends_with_cr = line.ends_with('\r');
let line = Line { offset, len, chars: line.trim_end().to_owned() };
offset += len;
replace(&mut last_line, Some((line, ends_with_cr))).map(|(l, _)| l)
})
.collect();
if let Some((l, _)) = last_line {
lines.push(l);
}
Self { file_name: "<anonymous>".to_string(), lines, len: offset }
}
}
impl Source {
/// Get the length of the total number of characters in the source.
pub fn length(&self) -> usize {
self.len
}
/// Return an iterator over the characters in the source.
pub fn chars(&self) -> impl Iterator<Item = char> + '_ {
self.lines.iter().map(|l| l.chars()).flatten()
}
/// Get access to a specific, zero-indexed [`Line`].
pub fn line(&self, idx: usize) -> Option<&Line> {
self.lines.get(idx)
}
/// Return an iterator over the [`Line`]s in this source.
pub fn lines(&self) -> impl ExactSizeIterator<Item = &Line> + '_ {
self.lines.iter()
}
/// Get the line that the given offset appears on, and the line/column numbers of the offset.
///
/// Note that the line/column numbers are zero-indexed.
pub fn get_offset_line(&self, offset: usize) -> Option<(&Line, usize, usize)> {
if offset <= self.len {
let idx = self.lines.binary_search_by_key(&offset, |line| line.offset).unwrap_or_else(|idx| idx.saturating_sub(1));
let line = &self.lines[idx];
assert!(offset >= line.offset, "offset = {}, line.offset = {}", offset, line.offset);
Some((line, idx, offset - line.offset))
}
else {
None
}
}
/// Get the range of lines that this span runs across.
///
/// The resulting range is guaranteed to contain valid line indices (i.e: those that can be used for
/// [`Source::line`]).
pub fn get_line_range(&self, span: &Range<usize>) -> Range<usize> {
let start = self.get_offset_line(span.start).map_or(0, |(_, l, _)| l);
let end = self.get_offset_line(span.end.saturating_sub(1).max(span.start)).map_or(self.lines.len(), |(_, l, _)| l + 1);
start..end
}
}
/// A [`Cache`] that fetches [`Source`]s from the filesystem.
#[derive(Default, Debug, Clone)]
pub struct FileCache {
files: HashMap<FileID, Source>,
}
impl FileCache {
/// Create a new [`FileCache`].
pub fn load_local<P>(&mut self, path: P) -> Result<FileID, std::io::Error>
where
P: AsRef<PathBuf>,
{
let path = path.as_ref();
let hasher = self.files.hasher();
let name_hash = {
let mut hasher = hasher.build_hasher();
path.hash(&mut hasher);
FileID { hash: hasher.finish() }
};
let text = std::fs::read_to_string(path)?;
let source = Source::from(text);
self.files.insert(name_hash, source);
Ok(name_hash)
}
/// Create a new [`FileCache`].
pub fn load_text<T, N>(&mut self, text: T, name: N) -> FileID
where
T: ToString,
N: ToString,
{
let name = name.to_string();
let hasher = self.files.hasher();
let name_hash = {
let mut hasher = hasher.build_hasher();
name.hash(&mut hasher);
FileID { hash: hasher.finish() }
};
let mut source = Source::from(text.to_string());
source.file_name = name;
self.files.insert(name_hash, source);
name_hash
}
/// Create a new [`FileCache`].
pub fn fetch(&mut self, file: &FileID) -> Result<&Source, std::io::Error> {
match self.files.get(file) {
Some(source) => Ok(source),
None => Err(std::io::Error::new(std::io::ErrorKind::NotFound, format!("File {:?} not found", file))),
}
}
/// Create a new [`FileCache`].
pub fn display(&self, file: &FileID) -> Option<&str> {
Some(self.files.get(file)?.file_name.as_str())
}
}