58 lines
1.5 KiB
Rust
58 lines
1.5 KiB
Rust
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//@ known-bug: #90110
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use std::fs::File;
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use std::io::{BufReader, BufRead};
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use std::str::Split;
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use std::path::Path;
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pub trait Parser<D>
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where dyn Parser<D>: Sized
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{
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fn new(split_header: Split<&str>) -> Self where Self: Sized;
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fn parse_line(&self, split_line: &Split<&str>) -> D;
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}
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pub struct CsvReader<D> {
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parser: Box<dyn Parser<D>>,
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reader: BufReader<File>,
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buf: String, // Buffer we will read into. Avoids re-allocation on each line.
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path: String, // Record this so we can return more informative error messages.
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line: usize, // Same motivation for this.
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}
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impl<D> CsvReader<D>
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where dyn Parser<D>: Sized
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{
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fn new<F>(path: &str, make_parser: F) -> CsvReader<D>
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where F: Fn(Split<char>) -> dyn Parser<D> {
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let file = match File::open(Path::new(path)) {
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Err(err) => panic!("Couldn't read {}: {}", path, err),
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Ok(file) => file,
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};
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let mut reader = BufReader::new(file);
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let mut buf = String::new();
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let parser = Box::new(match reader.read_line(&mut buf) {
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Err(err) => panic!("Failed to read the header line from {}: {}", path, err),
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Ok(_) => {
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let split_header = buf.split(',');
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make_parser(split_header)
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},
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});
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CsvReader {
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parser: parser,
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reader,
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buf,
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path: path.to_string(),
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line: 2,
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}
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}
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}
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pub fn main() {}
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