RangeLock example usage

General purpose RangeLock:

extern crate range_lock;
use range_lock::RangeLock;
use std::sync::{Arc, Barrier};
use std::thread;

// The data that will simultaneously be accessed from the threads.
let data = vec![10, 11, 12, 13];

// Embed the data in a RangeLock
// and clone atomic references to it for the threads.
let data_lock0 = Arc::new(RangeLock::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);

// Spawn first thread.
let thread0 = thread::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.
let thread1 = thread::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]
    }
});

// Wait for both threads to finish and check result.
thread0.join().expect("Thread 0 failed");
thread1.join().expect("Thread 1 failed");

// 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]);

RepRangeLock example usage

The RepRangeLock is a restricted range lock, that provides interleaved patterns of slices to the threads.

Locking a RepRangeLock is more lightweight than locking a RangeLock.

Please see the example below.

use range_lock::RepRangeLock;
use std::sync::Arc;
use std::thread;

let data = vec![1, 2,  3, 4,   5,  6,   // <- cycle 0
                7, 8,  9, 10,  11, 12]; // <- cycle 1
//              ^--^   ^---^   ^----^
//                |      |      |
//          offset-0  offset-1  offset-2

let lock = Arc::new(RepRangeLock::new(data,
                                      2,    // slice_len: Each slice has 2 elements.
                                      3));  // cycle_len: Each cycle has 3 slices (offsets).
let lock0 = Arc::clone(&lock);
let lock1 = Arc::clone(&lock);
let lock2 = Arc::clone(&lock);

let thread0 = thread::spawn(move || {
    // Lock slice offset 0:
    let mut guard = lock0.try_lock(0).expect("Failed to lock offset.");

    // Read:
    assert_eq!(guard[0][0], 1);     // Cycle 0, Slice element 0
    assert_eq!(guard[0][1], 2);     // Cycle 0, Slice element 1
    // let _ = guard[0][2];         // Would panic. Slice len is only 2.
    assert_eq!(guard[1][0], 7);     // Cycle 1, Slice element 0
    assert_eq!(guard[1][1], 8);     // Cycle 1, Slice element 1
    // let _ = guard[2][0];         // Would panic: The data vec is only 2 repeat cycles long.

    // Write:
    guard[0][0] = 10;               // Cycle 0, Slice element 0
    guard[0][1] = 20;               // Cycle 0, Slice element 1
    // guard[0][2] = 42;            // Would panic: Slice len is only 2.
    guard[1][0] = 30;               // Cycle 1, Slice element 0
    guard[1][1] = 40;               // Cycle 1, Slice element 1
    // guard[2][0] = 42;            // Would panic: The data vec is only 2 repeat cycles long.
});

let thread1 = thread::spawn(move || {
    // Lock slice offset 1:
    let mut guard = lock1.try_lock(1).expect("Failed to lock offset.");

    guard[0][0] = 100;              // Cycle 0, Slice element 0
    guard[0][1] = 200;              // Cycle 0, Slice element 1
    guard[1][0] = 300;              // Cycle 1, Slice element 0
    guard[1][1] = 400;              // Cycle 1, Slice element 1
});

let thread2 = thread::spawn(move || {
    // Lock slice offset 2:
    let mut guard = lock2.try_lock(2).expect("Failed to lock offset.");

    guard[0][0] = 1000;             // Cycle 0, Slice element 0
    guard[0][1] = 2000;             // Cycle 0, Slice element 1
    guard[1][0] = 3000;             // Cycle 1, Slice element 0
    guard[1][1] = 4000;             // Cycle 1, Slice element 1
});

thread0.join();
thread1.join();
thread2.join();

// Get the data that has been modified by the threads.
let data = Arc::try_unwrap(lock).expect("Thread is still using data.").into_inner();

assert_eq!(data,
           vec![10, 20, 100, 200, 1000, 2000,
                30, 40, 300, 400, 3000, 4000]);