Sample file copy / temp / creation in RUST (1.0.0-beta2)

rust_file_copy_test.rs

#[allow(unused_imports)]
use std::io;
use std::path::Path;
use std::fs::File;

type IoResult<T> = std::io::Result<T>;

extern crate tempdir;
extern crate rustc_serialize;
extern crate docopt;

use tempdir::*;
use docopt::Docopt;

static USAGE: &'static str = "
Usage: cp <source> <dest>
";

#[derive(RustcDecodable, Debug)]
struct Args {
    arg_source: String,
    arg_dest: String
}

fn main() {
    let args: Args = Docopt::new(USAGE)
        .and_then(|d| d.decode())
        .unwrap_or_else(|e| e.exit());

    println!("{:?}", args);

    println!("{:?}", process(
        Path::new(&args.arg_source),
        Path::new(&args.arg_dest)))
}

fn process(from: &Path, to: &Path) -> IoResult<u64> {
    // creates a new tempdir with the specified suffix
    let tempdir = try!(TempDir::new("skylight"));

    // open the input file
    let mut from_file = try!(File::open(from));

    // create a temporary file inside the tempdir
    let mut tempfile =
        try!(File::create(&tempdir.path().join("tmp1")));

    // copy the input file into the tempfile
    try!(io::copy(&mut from_file, &mut tempfile));

    // after processing, copy the tempfile into the output file
    let mut out = try!(File::create(to));

    return io::copy(&mut tempfile, &mut out);
}

/* toml: dependencies

[package]

name = "rust_file_copy_test"
version = "0.0.1"
authors = [ "john.koepi" ]

[dependencies]
tempdir = "*"
docopt = "*"
rustc-serialize = "*"

*/