pub struct ConcurrentQueue<T>(_);
Expand description

A concurrent queue.

Examples

use concurrent_queue::{ConcurrentQueue, PopError, PushError};

let q = ConcurrentQueue::bounded(2);

assert_eq!(q.push('a'), Ok(()));
assert_eq!(q.push('b'), Ok(()));
assert_eq!(q.push('c'), Err(PushError::Full('c')));

assert_eq!(q.pop(), Ok('a'));
assert_eq!(q.pop(), Ok('b'));
assert_eq!(q.pop(), Err(PopError::Empty));

Implementations

Creates a new bounded queue.

The queue allocates enough space for cap items.

Panics

If the capacity is zero, this constructor will panic.

Examples
use concurrent_queue::ConcurrentQueue;

let q = ConcurrentQueue::<i32>::bounded(100);

Creates a new unbounded queue.

Examples
use concurrent_queue::ConcurrentQueue;

let q = ConcurrentQueue::<i32>::unbounded();

Attempts to push an item into the queue.

If the queue is full or closed, the item is returned back as an error.

Examples
use concurrent_queue::{ConcurrentQueue, PushError};

let q = ConcurrentQueue::bounded(1);

// Push succeeds because there is space in the queue.
assert_eq!(q.push(10), Ok(()));

// Push errors because the queue is now full.
assert_eq!(q.push(20), Err(PushError::Full(20)));

// Close the queue, which will prevent further pushes.
q.close();

// Pushing now errors indicating the queue is closed.
assert_eq!(q.push(20), Err(PushError::Closed(20)));

// Pop the single item in the queue.
assert_eq!(q.pop(), Ok(10));

// Even though there is space, no more items can be pushed.
assert_eq!(q.push(20), Err(PushError::Closed(20)));

Attempts to pop an item from the queue.

If the queue is empty, an error is returned.

Examples
use concurrent_queue::{ConcurrentQueue, PopError};

let q = ConcurrentQueue::bounded(1);

// Pop errors when the queue is empty.
assert_eq!(q.pop(), Err(PopError::Empty));

// Push one item and close the queue.
assert_eq!(q.push(10), Ok(()));
q.close();

// Remaining items can be popped.
assert_eq!(q.pop(), Ok(10));

// Again, pop errors when the queue is empty,
// but now also indicates that the queue is closed.
assert_eq!(q.pop(), Err(PopError::Closed));

Returns true if the queue is empty.

Examples
use concurrent_queue::ConcurrentQueue;

let q = ConcurrentQueue::<i32>::unbounded();

assert!(q.is_empty());
q.push(1).unwrap();
assert!(!q.is_empty());

Returns true if the queue is full.

An unbounded queue is never full.

Examples
use concurrent_queue::ConcurrentQueue;

let q = ConcurrentQueue::bounded(1);

assert!(!q.is_full());
q.push(1).unwrap();
assert!(q.is_full());

Returns the number of items in the queue.

Examples
use concurrent_queue::ConcurrentQueue;

let q = ConcurrentQueue::unbounded();
assert_eq!(q.len(), 0);

assert_eq!(q.push(10), Ok(()));
assert_eq!(q.len(), 1);

assert_eq!(q.push(20), Ok(()));
assert_eq!(q.len(), 2);

Returns the capacity of the queue.

Unbounded queues have infinite capacity, represented as None.

Examples
use concurrent_queue::ConcurrentQueue;

let q = ConcurrentQueue::<i32>::bounded(7);
assert_eq!(q.capacity(), Some(7));

let q = ConcurrentQueue::<i32>::unbounded();
assert_eq!(q.capacity(), None);

Closes the queue.

Returns true if this call closed the queue, or false if it was already closed.

When a queue is closed, no more items can be pushed but the remaining items can still be popped.

Examples
use concurrent_queue::{ConcurrentQueue, PopError, PushError};

let q = ConcurrentQueue::unbounded();
assert_eq!(q.push(10), Ok(()));

assert!(q.close());  // `true` because this call closes the queue.
assert!(!q.close()); // `false` because the queue is already closed.

// Cannot push any more items when closed.
assert_eq!(q.push(20), Err(PushError::Closed(20)));

// Remaining items can still be popped.
assert_eq!(q.pop(), Ok(10));

// When no more items are present, the error is `Closed`.
assert_eq!(q.pop(), Err(PopError::Closed));

Returns true if the queue is closed.

Examples
use concurrent_queue::ConcurrentQueue;

let q = ConcurrentQueue::<i32>::unbounded();

assert!(!q.is_closed());
q.close();
assert!(q.is_closed());

Trait Implementations

Formats the value using the given formatter. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.