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use std::fs;
use std::io::{self, BufRead};
use std::path::Path;
#[derive(Default)]
#[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
pub struct SourceFile {
pub contents: String,
file_names: Vec<String>,
file_lines: Vec<usize>,
line_lengths: Vec<usize>,
}
impl SourceFile {
pub fn add_file(mut self, filename: impl AsRef<Path>) -> Result<Self, io::Error> {
let filename = filename.as_ref();
let mut file = io::BufReader::new(fs::File::open(filename)?);
let line_len = file.read_line(&mut self.contents)?;
if line_len == 0 {
return Ok(self);
}
self.line_lengths.push(line_len);
let mut num_lines = 1;
loop {
let line_len = file.read_line(&mut self.contents)?;
if line_len == 0 {
break;
}
self.line_lengths.push(line_len);
num_lines += 1;
}
self.file_names.push(format!("{}", filename.display()));
self.file_lines.push(num_lines);
Ok(self)
}
pub fn resolve_offset<'a>(&'a self, offset: usize) -> Option<Position<'a>> {
let mut line_acc = *self.line_lengths.get(0)?;
let mut line_idx = 0;
while line_acc <= offset {
line_idx += 1;
line_acc += *self.line_lengths.get(line_idx)?;
}
line_acc -= self.line_lengths[line_idx];
let mut file_acc = self.file_lines[0];
let mut file_idx = 0;
while file_acc <= line_idx {
file_idx += 1;
file_acc += self.file_lines[file_idx];
}
file_acc -= self.file_lines[file_idx];
Some(Position::new(&self.file_names[file_idx], line_idx - file_acc, offset - line_acc))
}
pub fn resolve_offset_span<'a>(&'a self, start: usize, end: usize) -> Option<Span<'a>> {
if end < start {
return None;
}
Some(Span {
start: self.resolve_offset(start)?,
end: self.resolve_offset(end)?,
})
}
}
#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
pub struct Position<'a> {
pub filename: &'a str,
pub line: usize,
pub col: usize,
}
impl<'a> Position<'a> {
fn new(filename: &'a str, line: usize, col: usize) -> Position<'a> {
Position { filename: filename.as_ref(), line, col }
}
}
#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
pub struct Span<'a> {
pub start: Position<'a>,
pub end: Position<'a>,
}
#[cfg(test)]
mod tests {
extern crate tempfile;
use super::{SourceFile, Position, Span};
use self::tempfile::NamedTempFile;
use std::io::Write;
#[test]
fn empty() {
let sourcefile = SourceFile::default();
assert!(sourcefile.resolve_offset(0).is_none());
}
#[test]
fn smoke() {
test_files(
&["A file with\ntwo lines.\n",
"Another file with\ntwo more lines.\n",
],
&[(0, (0, 0, 0)),
(5, (0, 0, 5)),
(11, (0, 0, 11)),
(12, (0, 1, 0)),
(13, (0, 1, 1)),
(13, (0, 1, 1)),
(22, (0, 1, 10)),
(23, (1, 0, 0)),
(24, (1, 0, 1)),
(40, (1, 0, 17)),
(41, (1, 1, 0)),
(42, (1, 1, 1)),
(56, (1, 1, 15)),
],
&[((0, 5), (0, 0, 0), (0, 0, 5)),
]
)
}
fn test_files<'a>(files: &[impl AsRef<str>],
offset_tests: &[(usize,
(usize, usize, usize))],
offset_span_tests: &[((usize, usize),
(usize, usize, usize),
(usize, usize, usize))])
{
let mut sourcefile = SourceFile::default();
let mut file_handles = Vec::new();
for contents in files {
let mut file = NamedTempFile::new().unwrap();
write!(file, "{}", contents.as_ref()).unwrap();
sourcefile = sourcefile.add_file(file.path()).unwrap();
file_handles.push(file);
}
for &(offset, (file_idx, line, col)) in offset_tests {
let filename = format!("{}", file_handles[file_idx].path().display());
let pos = sourcefile.resolve_offset(offset);
assert!(pos.is_some());
assert_eq!(pos.unwrap(), Position::new(&filename, line, col));
}
for &((start, end),
(file_idx_start, line_start, col_start),
(file_idx_end, line_end, col_end)) in offset_span_tests
{
let start_filename = format!("{}", file_handles[file_idx_start].path().display());
let end_filename = format!("{}", file_handles[file_idx_end].path().display());
assert_eq!(sourcefile.resolve_offset_span(start, end).unwrap(),
Span {
start: Position::new(&start_filename, line_start, col_start),
end: Position::new(&end_filename, line_end, col_end),
});
}
}
}