flexible-locks 0.1.0

// Copyright 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.

// Tests from src/libstd/sync/mutex.rs in
// https://github.com/rust-lang/rust

use std::sync::Arc;
use std::sync::mpsc::channel;
use std::sync::atomic::{AtomicUsize, Ordering};
use std::thread;

#[derive(Eq, PartialEq, Debug)]
struct NonCopy(i32);

#[test]
fn smoke() {
    let m = Mutex::new(());
    drop(m.lock());
    drop(m.lock());
}

#[test]
fn lots_and_lots() {
    const J: u32 = 1000;
    const K: u32 = 3;

    let m = Arc::new(Mutex::new(0));

    fn inc(m: &Mutex<u32>) {
        for _ in 0..J {
            *m.lock() += 1;
        }
    }

    let (tx, rx) = channel();
    for _ in 0..K {
        let tx2 = tx.clone();
        let m2 = m.clone();
        thread::spawn(move || {
            inc(&m2);
            tx2.send(()).unwrap();
        });
        let tx2 = tx.clone();
        let m2 = m.clone();
        thread::spawn(move || {
            inc(&m2);
            tx2.send(()).unwrap();
        });
    }

    drop(tx);
    for _ in 0..2 * K {
        rx.recv().unwrap();
    }
    assert_eq!(*m.lock(), J * K * 2);
}

#[test]
fn test_into_inner() {
    let m = Mutex::new(NonCopy(10));
    assert_eq!(m.into_inner(), NonCopy(10));
}

#[test]
fn test_into_inner_drop() {
    struct Foo(Arc<AtomicUsize>);
    impl Drop for Foo {
        fn drop(&mut self) {
            self.0.fetch_add(1, Ordering::SeqCst);
        }
    }
    let num_drops = Arc::new(AtomicUsize::new(0));
    let m = Mutex::new(Foo(num_drops.clone()));
    assert_eq!(num_drops.load(Ordering::SeqCst), 0);
    {
        let _inner = m.into_inner();
        assert_eq!(num_drops.load(Ordering::SeqCst), 0);
    }
    assert_eq!(num_drops.load(Ordering::SeqCst), 1);
}

#[test]
fn test_get_mut() {
    let mut m = Mutex::new(NonCopy(10));
    *m.get_mut() = NonCopy(20);
    assert_eq!(m.into_inner(), NonCopy(20));
}

#[test]
fn test_mutex_arc_nested() {
    // Tests nested mutexes and access
    // to underlying data.
    let arc = Arc::new(Mutex::new(1));
    let arc2 = Arc::new(Mutex::new(arc));
    let (tx, rx) = channel();
    let _t = thread::spawn(move || {
        let lock = arc2.lock();
        let lock2 = lock.lock();
        assert_eq!(*lock2, 1);
        tx.send(()).unwrap();
    });
    rx.recv().unwrap();
}

#[test]
fn test_mutex_unsized() {
    let mutex: &Mutex<[i32]> = &Mutex::new([1, 2, 3]);
    {
        let b = &mut *mutex.lock();
        b[0] = 4;
        b[2] = 5;
    }
    let comp: &[i32] = &[4, 2, 5];
    assert_eq!(&*mutex.lock(), comp);
}