示例

在这个示例中，展示了 ChangeTracker 的功能。

use futures::stream::StreamExt;

// Wrap an integer `with ChangeTracker`
let mut change_tracker = async_change_tracker::ChangeTracker::new( 123 );

// Create an receiver that fires when the value changes. The channel size
// is 1, meaning at most one change can be buffered before backpressure
// is applied.
let rx = change_tracker.get_changes(1);

// In this example take a single change and check that the old and new value
// are correct.
let rx_printer = rx.take(1).for_each(|(old_value, new_value)| {
    assert_eq!( old_value, 123);
    assert_eq!( new_value, 124);
    futures::future::ready(())
});

// Now, check and then change the value.
change_tracker.modify(|mut_ref_value| {
    assert_eq!(*mut_ref_value, 123);
    *mut_ref_value += 1;
});

// Wait until the stream is done. In this example, the stream ends due to
// the use of `.take(1)` prior to `for_each` above. In normal usage,
// typically the stream would finish for a different reason.
futures::executor::block_on(rx_printer);

// Finally, check that the final value is as expected.
assert!(*change_tracker.as_ref() == 124);

测试

要测试

cargo test

许可协议：MIT/Apache-2.0