Struct tarantool::fiber::async::mutex::Mutex

pub struct Mutex<T: ?Sized> { /* private fields */ }

An asynchronous Mutex-like type.

This type acts similarly to std::sync::Mutex, with two major differences: Mutex::lock is an async method so does not block, and the lock guard is designed to be held across .await points.

Prefer this type to crate::fiber::mutex::Mutex if used in async contexts. This Mutex makes fiber yielding calls to be explicit with .await syntax and will help avoid deadlocks in case of multiple futures used in join_all or similar combinators.

Implementations

impl<T: ?Sized> Mutex<T>

pub fn new(t: T) -> Mutex<T>

where T: Sized,

Creates a new mutex in an unlocked state ready for use.

Examples

use tarantool::fiber::r#async::Mutex;

let mutex = Mutex::new(0);

pub async fn lock(&self) -> MutexGuard<'_, T>

Locks this mutex, causing the current future/fiber to yield until the lock has been acquired. When the lock has been acquired, function returns a MutexGuard. The lock will be unlocked when the guard is dropped.

Examples

use std::rc::Rc;
use tarantool::fiber::{start_async, block_on, r#async::Mutex};

let mutex = Rc::new(Mutex::new(0));
let c_mutex = Rc::clone(&mutex);

start_async(async move {
    *c_mutex.lock().await = 10;
}).join();
block_on(async { assert_eq!(*mutex.lock().await, 10) });

pub fn try_lock(&self) -> Option<MutexGuard<'_, T>>

Attempts to acquire this lock.

If the lock could not be acquired at this time, then None is returned. Otherwise, a MutexGuard is returned. The lock will be unlocked when the guard is dropped.

This function does not yield.

Examples

use std::rc::Rc;
use tarantool::fiber::{start_proc, r#async::Mutex};

let mutex = Rc::new(Mutex::new(0));
let c_mutex = Rc::clone(&mutex);

start_proc(move || {
    let mut lock = c_mutex.try_lock();
    if let Some(ref mut mutex) = lock {
        **mutex = 10;
    } else {
        println!("try_lock failed");
    }
}).join();
assert_eq!(*mutex.try_lock().unwrap(), 10);

pub fn unlock(guard: MutexGuard<'_, T>)

Immediately drops the guard, and consequently unlocks the mutex.

This function is equivalent to calling drop on the guard but is more self-documenting. Alternately, the guard will be automatically dropped when it goes out of scope.

use tarantool::fiber::r#async::Mutex;
let mutex = Mutex::new(0);

let mut guard = mutex.try_lock().unwrap();
*guard += 20;
Mutex::unlock(guard);

pub fn into_inner(self) -> T

where T: Sized,

Consumes this mutex, returning the underlying data.

Examples

use tarantool::fiber::r#async::Mutex;

let mutex = Mutex::new(0);
assert_eq!(mutex.into_inner(), 0);

pub fn get_mut(&mut self) -> &mut T

Returns a mutable reference to the underlying data.

Since this call borrows the Mutex mutably, no actual locking needs to take place – the mutable borrow statically guarantees no locks exist.

Examples

use tarantool::fiber::r#async::Mutex;

let mut mutex = Mutex::new(0);
*mutex.get_mut() = 10;
assert_eq!(*mutex.try_lock().unwrap(), 10);

Trait Implementations

impl<T: Debug + ?Sized> Debug for Mutex<T>

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

Formats the value using the given formatter.

impl<T: ?Sized + Default> Default for Mutex<T>

fn default() -> Mutex<T>

Creates a Mutex<T>, with the Default value for T.

impl<T> From<T> for Mutex<T>

fn from(t: T) -> Self

Creates a new mutex in an unlocked state ready for use. This is equivalent to Mutex::new.