49 lines
1.3 KiB
Rust
49 lines
1.3 KiB
Rust
#[macro_use(quick_error)] extern crate quick_error;
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use std::io::{self, stderr, Read, Write};
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use std::fs::File;
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use std::env;
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use std::num::ParseIntError;
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use std::path::{Path, PathBuf};
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use quick_error::ResultExt;
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quick_error! {
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#[derive(Debug)]
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pub enum Error {
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NoFileName {
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description("no file name specified")
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}
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Io(err: io::Error, path: PathBuf) {
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display("could not read file {:?}: {}", path, err)
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context(path: &'a Path, err: io::Error)
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-> (err, path.to_path_buf())
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}
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Parse(err: ParseIntError, path: PathBuf) {
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display("could not parse file {:?}: {}", path, err)
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context(path: &'a Path, err: ParseIntError)
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-> (err, path.to_path_buf())
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}
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}
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}
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fn parse_file() -> Result<u64, Error> {
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let fname = try!(env::args().skip(1).next().ok_or(Error::NoFileName));
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let fname = Path::new(&fname);
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let mut file = try!(File::open(fname).context(fname));
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let mut buf = String::new();
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try!(file.read_to_string(&mut buf).context(fname));
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Ok(try!(buf.parse().context(fname)))
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}
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fn main() {
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match parse_file() {
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Ok(val) => {
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println!("Read: {}", val);
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}
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Err(e) => {
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writeln!(&mut stderr(), "Error: {}", e).ok();
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}
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}
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}
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