Struct crossbeam_channel::Receiver

source ·
pub struct Receiver<T> { /* private fields */ }
Expand description

The receiving side of a channel.

§Examples

use std::thread;
use std::time::Duration;
use crossbeam_channel::unbounded;

let (s, r) = unbounded();

thread::spawn(move || {
    let _ = s.send(1);
    thread::sleep(Duration::from_secs(1));
    let _ = s.send(2);
});

assert_eq!(r.recv(), Ok(1)); // Received immediately.
assert_eq!(r.recv(), Ok(2)); // Received after 1 second.

Implementations§

source§

impl<T> Receiver<T>

source

pub fn try_recv(&self) -> Result<T, TryRecvError>

Attempts to receive a message from the channel without blocking.

This method will either receive a message from the channel immediately or return an error if the channel is empty.

If called on a zero-capacity channel, this method will receive a message only if there happens to be a send operation on the other side of the channel at the same time.

§Examples
use crossbeam_channel::{unbounded, TryRecvError};

let (s, r) = unbounded();
assert_eq!(r.try_recv(), Err(TryRecvError::Empty));

s.send(5).unwrap();
drop(s);

assert_eq!(r.try_recv(), Ok(5));
assert_eq!(r.try_recv(), Err(TryRecvError::Disconnected));
source

pub fn recv(&self) -> Result<T, RecvError>

Blocks the current thread until a message is received or the channel is empty and disconnected.

If the channel is empty and not disconnected, this call will block until the receive operation can proceed. If the channel is empty and becomes disconnected, this call will wake up and return an error.

If called on a zero-capacity channel, this method will wait for a send operation to appear on the other side of the channel.

§Examples
use std::thread;
use std::time::Duration;
use crossbeam_channel::{unbounded, RecvError};

let (s, r) = unbounded();

thread::spawn(move || {
    thread::sleep(Duration::from_secs(1));
    s.send(5).unwrap();
    drop(s);
});

assert_eq!(r.recv(), Ok(5));
assert_eq!(r.recv(), Err(RecvError));
source

pub fn recv_timeout(&self, timeout: Duration) -> Result<T, RecvTimeoutError>

Waits for a message to be received from the channel, but only for a limited time.

If the channel is empty and not disconnected, this call will block until the receive operation can proceed or the operation times out. If the channel is empty and becomes disconnected, this call will wake up and return an error.

If called on a zero-capacity channel, this method will wait for a send operation to appear on the other side of the channel.

§Examples
use std::thread;
use std::time::Duration;
use crossbeam_channel::{unbounded, RecvTimeoutError};

let (s, r) = unbounded();

thread::spawn(move || {
    thread::sleep(Duration::from_secs(1));
    s.send(5).unwrap();
    drop(s);
});

assert_eq!(
    r.recv_timeout(Duration::from_millis(500)),
    Err(RecvTimeoutError::Timeout),
);
assert_eq!(
    r.recv_timeout(Duration::from_secs(1)),
    Ok(5),
);
assert_eq!(
    r.recv_timeout(Duration::from_secs(1)),
    Err(RecvTimeoutError::Disconnected),
);
source

pub fn recv_deadline(&self, deadline: Instant) -> Result<T, RecvTimeoutError>

Waits for a message to be received from the channel, but only before a given deadline.

If the channel is empty and not disconnected, this call will block until the receive operation can proceed or the operation times out. If the channel is empty and becomes disconnected, this call will wake up and return an error.

If called on a zero-capacity channel, this method will wait for a send operation to appear on the other side of the channel.

§Examples
use std::thread;
use std::time::{Instant, Duration};
use crossbeam_channel::{unbounded, RecvTimeoutError};

let (s, r) = unbounded();

thread::spawn(move || {
    thread::sleep(Duration::from_secs(1));
    s.send(5).unwrap();
    drop(s);
});

let now = Instant::now();

assert_eq!(
    r.recv_deadline(now + Duration::from_millis(500)),
    Err(RecvTimeoutError::Timeout),
);
assert_eq!(
    r.recv_deadline(now + Duration::from_millis(1500)),
    Ok(5),
);
assert_eq!(
    r.recv_deadline(now + Duration::from_secs(5)),
    Err(RecvTimeoutError::Disconnected),
);
source

pub fn is_empty(&self) -> bool

Returns true if the channel is empty.

Note: Zero-capacity channels are always empty.

§Examples
use crossbeam_channel::unbounded;

let (s, r) = unbounded();

assert!(r.is_empty());
s.send(0).unwrap();
assert!(!r.is_empty());
source

pub fn is_full(&self) -> bool

Returns true if the channel is full.

Note: Zero-capacity channels are always full.

§Examples
use crossbeam_channel::bounded;

let (s, r) = bounded(1);

assert!(!r.is_full());
s.send(0).unwrap();
assert!(r.is_full());
source

pub fn len(&self) -> usize

Returns the number of messages in the channel.

§Examples
use crossbeam_channel::unbounded;

let (s, r) = unbounded();
assert_eq!(r.len(), 0);

s.send(1).unwrap();
s.send(2).unwrap();
assert_eq!(r.len(), 2);
source

pub fn capacity(&self) -> Option<usize>

If the channel is bounded, returns its capacity.

§Examples
use crossbeam_channel::{bounded, unbounded};

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

let (_, r) = bounded::<i32>(5);
assert_eq!(r.capacity(), Some(5));

let (_, r) = bounded::<i32>(0);
assert_eq!(r.capacity(), Some(0));
source

pub fn iter(&self) -> Iter<'_, T>

A blocking iterator over messages in the channel.

Each call to next blocks waiting for the next message and then returns it. However, if the channel becomes empty and disconnected, it returns None without blocking.

§Examples
use std::thread;
use crossbeam_channel::unbounded;

let (s, r) = unbounded();

thread::spawn(move || {
    s.send(1).unwrap();
    s.send(2).unwrap();
    s.send(3).unwrap();
    drop(s); // Disconnect the channel.
});

// Collect all messages from the channel.
// Note that the call to `collect` blocks until the sender is dropped.
let v: Vec<_> = r.iter().collect();

assert_eq!(v, [1, 2, 3]);
source

pub fn try_iter(&self) -> TryIter<'_, T>

A non-blocking iterator over messages in the channel.

Each call to next returns a message if there is one ready to be received. The iterator never blocks waiting for the next message.

§Examples
use std::thread;
use std::time::Duration;
use crossbeam_channel::unbounded;

let (s, r) = unbounded::<i32>();

thread::spawn(move || {
    s.send(1).unwrap();
    thread::sleep(Duration::from_secs(1));
    s.send(2).unwrap();
    thread::sleep(Duration::from_secs(2));
    s.send(3).unwrap();
});

thread::sleep(Duration::from_secs(2));

// Collect all messages from the channel without blocking.
// The third message hasn't been sent yet so we'll collect only the first two.
let v: Vec<_> = r.try_iter().collect();

assert_eq!(v, [1, 2]);
source

pub fn same_channel(&self, other: &Receiver<T>) -> bool

Returns true if receivers belong to the same channel.

§Examples
use crossbeam_channel::unbounded;

let (_, r) = unbounded::<usize>();

let r2 = r.clone();
assert!(r.same_channel(&r2));

let (_, r3) = unbounded();
assert!(!r.same_channel(&r3));

Trait Implementations§

source§

impl<T> Clone for Receiver<T>

source§

fn clone(&self) -> Self

Returns a copy of the value. Read more
1.0.0 · source§

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
source§

impl<T> Debug for Receiver<T>

source§

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

Formats the value using the given formatter. Read more
source§

impl<T> Drop for Receiver<T>

source§

fn drop(&mut self)

Executes the destructor for this type. Read more
source§

impl<'a, T> IntoIterator for &'a Receiver<T>

§

type Item = T

The type of the elements being iterated over.
§

type IntoIter = Iter<'a, T>

Which kind of iterator are we turning this into?
source§

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value. Read more
source§

impl<T> IntoIterator for Receiver<T>

§

type Item = T

The type of the elements being iterated over.
§

type IntoIter = IntoIter<T>

Which kind of iterator are we turning this into?
source§

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value. Read more
source§

impl<T> RefUnwindSafe for Receiver<T>

source§

impl<T: Send> Send for Receiver<T>

source§

impl<T: Send> Sync for Receiver<T>

source§

impl<T> UnwindSafe for Receiver<T>

Auto Trait Implementations§

§

impl<T> Freeze for Receiver<T>

§

impl<T> Unpin for Receiver<T>
where T: Unpin,

Blanket Implementations§

source§

impl<T> Any for T
where T: 'static + ?Sized,

source§

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
source§

impl<T> Borrow<T> for T
where T: ?Sized,

source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
source§

impl<T> BorrowMut<T> for T
where T: ?Sized,

source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
source§

impl<T> From<T> for T

source§

fn from(t: T) -> T

Returns the argument unchanged.

source§

impl<T, U> Into<U> for T
where U: From<T>,

source§

fn into(self) -> U

Calls U::from(self).

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

source§

impl<T> ToOwned for T
where T: Clone,

§

type Owned = T

The resulting type after obtaining ownership.
source§

fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
source§

fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
source§

impl<T, U> TryFrom<U> for T
where U: Into<T>,

§

type Error = Infallible

The type returned in the event of a conversion error.
source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
source§

impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

§

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.