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