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// -*- coding: utf-8 -*-
//
// Copyright 2021-2023 Michael Büsch <m@bues.ch>
//
// Licensed under the Apache License version 2.0
// or the MIT license, at your option.
// SPDX-License-Identifier: Apache-2.0 OR MIT
//
use range_lock::VecRangeLock;
use std::sync::{Arc, Barrier};
use std::thread;
#[test]
fn test_rangelock() {
// The data that will simultaneously be accessed from the threads.
let data = vec![10, 11, 12, 13];
// Embed the data in a VecRangeLock
// and clone atomic references to it for the threads.
let data_lock0 = Arc::new(VecRangeLock::new(data));
let data_lock1 = Arc::clone(&data_lock0);
let data_lock2 = Arc::clone(&data_lock0);
// Thread barrier, only for demonstration purposes.
let barrier0 = Arc::new(Barrier::new(2));
let barrier1 = Arc::clone(&barrier0);
thread::scope(|s| {
// Spawn first thread.
s.spawn(move || {
{
let mut guard = data_lock0.try_lock(0..2).expect("T0: Failed to lock 0..2");
guard[0] = 100; // Write to data[0]
}
barrier0.wait(); // Synchronize with second thread.
{
let guard = data_lock0.try_lock(2..4).expect("T0: Failed to lock 2..4");
assert_eq!(guard[0], 200); // Read from data[2]
}
});
// Spawn second thread.
s.spawn(move || {
{
let mut guard = data_lock1.try_lock(2..4).expect("T1: Failed to lock 2..4");
guard[0] = 200; // Write to data[2]
}
barrier1.wait(); // Synchronize with first thread.
{
let guard = data_lock1.try_lock(0..2).expect("T1: Failed to lock 0..2");
assert_eq!(guard[0], 100); // Read from data[0]
}
});
});
// Unwrap the data from the lock.
let data = Arc::try_unwrap(data_lock2)
.expect("Arc unwrap failed")
.into_inner();
// Check the data that has been modified by the threads.
assert_eq!(data, vec![100, 11, 200, 13]);
}
#[test]
fn test_conflict() {
let data = vec![10, 11, 12, 13];
let data_lock0 = Arc::new(VecRangeLock::new(data));
let data_lock1 = Arc::clone(&data_lock0);
let barrier0 = Arc::new(Barrier::new(2));
let barrier1 = Arc::clone(&barrier0);
thread::scope(|s| {
s.spawn(move || {
let mut _guard = data_lock0.try_lock(0..2).expect("T0: Failed to lock 0..2");
barrier0.wait();
// try_lock() conflict happens in second thread.
barrier0.wait();
});
s.spawn(move || {
barrier1.wait();
// thread0 holds lock to 0..2, which conflicts with 1..4.
assert!(data_lock1.try_lock(1..4).is_err());
barrier1.wait();
});
});
}
// vim: ts=4 sw=4 expandtab
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