rust/src/test/run-pass/hashmap-memory.rs

// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

#![allow(unknown_features)]
#![feature(unboxed_closures, std_misc)]

/**
   A somewhat reduced test case to expose some Valgrind issues.

   This originally came from the word-count benchmark.
*/

pub fn map(filename: String, mut emit: map_reduce::putter) {
    emit(filename, "1".to_string());
}

mod map_reduce {
    use std::collections::HashMap;
    use std::sync::mpsc::{channel, Sender};
    use std::str;
    use std::thread::Thread;

    pub type putter<'a> = Box<FnMut(String, String) + 'a>;

    pub type mapper = extern fn(String, putter);

    enum ctrl_proto { find_reducer(Vec<u8>, Sender<isize>), mapper_done, }

    fn start_mappers(ctrl: Sender<ctrl_proto>, inputs: Vec<String>) {
        for i in &inputs {
            let ctrl = ctrl.clone();
            let i = i.clone();
            Thread::spawn(move|| map_task(ctrl.clone(), i.clone()) );
        }
    }

    fn map_task(ctrl: Sender<ctrl_proto>, input: String) {
        let mut intermediates = HashMap::new();

        fn emit(im: &mut HashMap<String, isize>,
                ctrl: Sender<ctrl_proto>, key: String,
                _val: String) {
            if im.contains_key(&key) {
                return;
            }
            let (tx, rx) = channel();
            println!("sending find_reducer");
            ctrl.send(ctrl_proto::find_reducer(key.as_bytes().to_vec(), tx)).unwrap();
            println!("receiving");
            let c = rx.recv().unwrap();
            println!("{}", c);
            im.insert(key, c);
        }

        let ctrl_clone = ctrl.clone();
        // FIXME (#22405): Replace `Box::new` with `box` here when/if possible.
        ::map(input, Box::new(|a,b| emit(&mut intermediates, ctrl.clone(), a, b)));
        ctrl_clone.send(ctrl_proto::mapper_done).unwrap();
    }

    pub fn map_reduce(inputs: Vec<String>) {
        let (tx, rx) = channel();

        // This task becomes the master control task. It spawns others
        // to do the rest.

        let mut reducers: HashMap<String, isize>;

        reducers = HashMap::new();

        start_mappers(tx, inputs.clone());

        let mut num_mappers = inputs.len() as isize;

        while num_mappers > 0 {
            match rx.recv().unwrap() {
              ctrl_proto::mapper_done => { num_mappers -= 1; }
              ctrl_proto::find_reducer(k, cc) => {
                let mut c;
                match reducers.get(&str::from_utf8(&k).unwrap().to_string()) {
                  Some(&_c) => { c = _c; }
                  None => { c = 0; }
                }
                cc.send(c).unwrap();
              }
            }
        }
    }
}

pub fn main() {
    map_reduce::map_reduce(
        vec!("../src/test/run-pass/hashmap-memory.rs".to_string()));
}