Struct qutex::FutureGuard

pub struct FutureGuard<T> { /* private fields */ }

A future which resolves to a Guard.

Implementations

impl<T> FutureGuard<T>

pub fn wait(self) -> Result<Guard<T>, Canceled>

Blocks the current thread until this future resolves.

Examples found in repository

examples/qutex.rs (line 40)

fn main() {
    let thread_count = 100;
    let mut threads = Vec::with_capacity(thread_count);
    let start_val = 0;

    // Create a `Qutex` protecting a start value of zero.
    let qutex = Qutex::new(start_val);

    // Spawn several threads, each adding 1 to the protected value.
    for _ in 0..thread_count {
        // Obtain a 'guard' (akin to a `std::sync::MutexGuard`).
        let future_val = qutex.clone().lock();

        // Add 1 to the protected value. `future_val` is a `FutureGuard` which
        // will resolve to a `Guard` providing mutable access to the protected
        // value. The guard can be passed between futures combinators and will
        // unlock the `Qutex` when dropped.
        let future_add = future_val.map(|mut val| {
            *val += 1;
        });

        // Spawn a thread which blocks upon completion of the above lock and
        // add operations.
        threads.push(thread::spawn(|| {
            future_add.wait().unwrap();
        }));
    }

    for thread in threads {
        thread.join().unwrap();
    }

    let val = qutex.lock().wait().unwrap();
    assert_eq!(*val, start_val + thread_count);
    println!("Qutex final value: {}", *val);
}

Trait Implementations

impl<T: Debug> Debug for FutureGuard<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T> Drop for FutureGuard<T>

fn drop(&mut self)

Gracefully unlock if this guard has a lock acquired but has not yet been polled to completion.

impl<T> Future for FutureGuard<T>

type Item = Guard<T>

The type of value that this future will resolved with if it is successful.

type Error = Canceled

The type of error that this future will resolve with if it fails in a normal fashion.

fn poll(&mut self) -> Poll<Self::Item, Self::Error>

Query this future to see if its value has become available, registering interest if it is not.

fn wait(self) -> Result<Self::Item, Self::Error>

where Self: Sized,

Block the current thread until this future is resolved.

fn map<F, U>(self, f: F) -> Map<Self, F>

where F: FnOnce(Self::Item) -> U, Self: Sized,

Map this future’s result to a different type, returning a new future of the resulting type.

fn map_err<F, E>(self, f: F) -> MapErr<Self, F>

where F: FnOnce(Self::Error) -> E, Self: Sized,

Map this future’s error to a different error, returning a new future.

fn from_err<E>(self) -> FromErr<Self, E>

where E: From<Self::Error>, Self: Sized,

Map this future’s error to any error implementing From for this future’s Error, returning a new future.

fn then<F, B>(self, f: F) -> Then<Self, B, F>

where F: FnOnce(Result<Self::Item, Self::Error>) -> B, B: IntoFuture, Self: Sized,

Chain on a computation for when a future finished, passing the result of the future to the provided closure f.

fn and_then<F, B>(self, f: F) -> AndThen<Self, B, F>

where F: FnOnce(Self::Item) -> B, B: IntoFuture<Error = Self::Error>, Self: Sized,

Execute another future after this one has resolved successfully.

fn or_else<F, B>(self, f: F) -> OrElse<Self, B, F>

where F: FnOnce(Self::Error) -> B, B: IntoFuture<Item = Self::Item>, Self: Sized,

Execute another future if this one resolves with an error.

fn select<B>(self, other: B) -> Select<Self, <B as IntoFuture>::Future>

where B: IntoFuture<Item = Self::Item, Error = Self::Error>, Self: Sized,

Waits for either one of two futures to complete.

fn select2<B>(self, other: B) -> Select2<Self, <B as IntoFuture>::Future>

where B: IntoFuture, Self: Sized,

Waits for either one of two differently-typed futures to complete.

fn join<B>(self, other: B) -> Join<Self, <B as IntoFuture>::Future>

where B: IntoFuture<Error = Self::Error>, Self: Sized,

Joins the result of two futures, waiting for them both to complete.

fn join3<B, C>( self, b: B, c: C ) -> Join3<Self, <B as IntoFuture>::Future, <C as IntoFuture>::Future>

where B: IntoFuture<Error = Self::Error>, C: IntoFuture<Error = Self::Error>, Self: Sized,

Same as join, but with more futures.

fn join4<B, C, D>( self, b: B, c: C, d: D ) -> Join4<Self, <B as IntoFuture>::Future, <C as IntoFuture>::Future, <D as IntoFuture>::Future>

where B: IntoFuture<Error = Self::Error>, C: IntoFuture<Error = Self::Error>, D: IntoFuture<Error = Self::Error>, Self: Sized,

Same as join, but with more futures.

fn join5<B, C, D, E>( self, b: B, c: C, d: D, e: E ) -> Join5<Self, <B as IntoFuture>::Future, <C as IntoFuture>::Future, <D as IntoFuture>::Future, <E as IntoFuture>::Future>

where B: IntoFuture<Error = Self::Error>, C: IntoFuture<Error = Self::Error>, D: IntoFuture<Error = Self::Error>, E: IntoFuture<Error = Self::Error>, Self: Sized,

Same as join, but with more futures.

fn into_stream(self) -> IntoStream<Self>

where Self: Sized,

Convert this future into a single element stream.

fn fuse(self) -> Fuse<Self>

where Self: Sized,

Fuse a future such that poll will never again be called once it has completed.

fn inspect<F>(self, f: F) -> Inspect<Self, F>

where F: FnOnce(&Self::Item), Self: Sized,

Do something with the item of a future, passing it on.

fn shared(self) -> Shared<Self>

where Self: Sized,

Create a cloneable handle to this future where all handles will resolve to the same result.