murmur3.rs

use clap::{crate_name, crate_version, App, Arg};
use indicatif::{ParallelProgressIterator, ProgressStyle};
use murmur3::murmur3_x64_128;
use rayon::iter::{IntoParallelRefIterator, ParallelIterator};
use std::fs::metadata;
use std::fs::File;
use std::io::prelude::*;
use std::sync::{Arc, Mutex};
use walkdir::WalkDir;

fn main() {
    let matches = App::new(crate_name!())
        .version(crate_version!())
        .author("Vadim Velicodnii <vadim@velikodniy.name>")
        .about("Computes MurMur3 (128 bit, x64) hashes for the files in a directory")
        .arg(
            Arg::with_name("dir_name")
                .value_name("DIR")
                .about("Directory for scanning")
                .required(true),
        )
        .arg(
            Arg::with_name("output_file")
                .short('o')
                .long("output")
                .value_name("OUTPUT")
                .about("File for the output")
                .required(true),
        )
        .get_matches();
    let dir_name = matches.value_of("dir_name").unwrap();
    let files = WalkDir::new(dir_name)
        .into_iter()
        .filter_map(|e| e.ok())
        .collect::<Vec<_>>();
    let pbar = indicatif::ProgressBar::new(files.len() as u64);
    pbar.set_style(
        ProgressStyle::default_bar()
            .template("[{elapsed_precise}] ETA: [{eta_precise}] {wide_bar} {pos:>7}/{len:7} {msg}"),
    );
    let output = File::create(matches.value_of("output_file").unwrap()).unwrap();
    let output_arc = Arc::new(Mutex::new(output));
    files
        .par_iter()
        .progress_with(pbar)
        .filter_map(|e| {
            if metadata(e.path()).unwrap().is_file() {
                Some(e)
            } else {
                None
            }
        })
        .map(|e| {
            let mut file = File::open(e.path()).unwrap();
            let hash = murmur3_x64_128(&mut file, 0).unwrap();
            (e, hash)
        })
        .for_each(|d| {
            let (e, h) = d;
            let line = format!("{:032x} {}\n", h, e.path().display());
            if output_arc.lock().unwrap().write_all(line.as_bytes()).is_err() {
                panic!("unable to write to the file")
            };
        });
}