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

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

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

use std;

import option = option::t;
import option::some;
import option::none;
import str;
import vec;
import std::map;
import task;
import comm::chan;
import comm::port;
import comm::send;
import comm::recv;
import comm;

fn map(filename: str, emit: map_reduce::putter) { emit(filename, "1"); }

mod map_reduce {
    export putter;
    export mapper;
    export map_reduce;

    type putter = fn@(str, str);

    type mapper = fn(str, putter);

    tag ctrl_proto { find_reducer([u8], chan<int>); mapper_done; }

    fn start_mappers(ctrl: chan<ctrl_proto>, inputs: [str]) {
        for i: str in inputs {
            task::spawn {|| map_task(ctrl, i); };
        }
    }

    fn map_task(ctrl: chan<ctrl_proto>, input: str) {
        let intermediates = map::new_str_hash();

        fn emit(im: map::hashmap<str, int>, ctrl: chan<ctrl_proto>, key: str,
                val: str) {
            let c;
            alt im.find(key) {
              some(_c) { c = _c }
              none. {
                let p = port();
                #error("sending find_reducer");
                send(ctrl, find_reducer(str::bytes(key), chan(p)));
                #error("receiving");
                c = recv(p);
                log(error, c);
                im.insert(key, c);
              }
            }
        }

        map(input, bind emit(intermediates, ctrl, _, _));
        send(ctrl, mapper_done);
    }

    fn map_reduce(inputs: [str]) {
        let ctrl = port();

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

        let reducers: map::hashmap<str, int>;

        reducers = map::new_str_hash();

        start_mappers(chan(ctrl), inputs);

        let num_mappers = vec::len(inputs) as int;

        while num_mappers > 0 {
            alt recv(ctrl) {
              mapper_done. { num_mappers -= 1; }
              find_reducer(k, cc) {
                let c;
                alt reducers.find(str::unsafe_from_bytes(k)) {
                  some(_c) { c = _c; }
                  none. { c = 0; }
                }
                send(cc, c);
              }
            }
        }
    }
}

fn main() {
    map_reduce::map_reduce(["../src/test/run-pass/hashmap-memory.rs"]);
}