Struct Receiver

Source

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

Expand description

The sending side of a channel, almost identical to crossbeam_channel::Receiver. The only difference is that you can make one channel depend on another channel. If channel A depends on channel B, channel A will ACT disconnected when channel B is disconnected. This mean that dependency is not transitive. If channel Z depends on channel A, channel Z will not ACT disconnected when channel B is disconnected.

§Examples

Channel without dependency:

use std::thread;
use std::time::Duration;
use crossbeam_channel::RecvError;
use lambda_channel::channel::new_channel;

let (s, r) = new_channel(None);

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.
assert_eq!(r.recv(), Err(RecvError)); // All senders have been dropped

Channel with dependency:

use std::thread;
use std::time::Duration;
use crossbeam_channel::{RecvError, SendError};
use lambda_channel::channel::{new_channel, new_channel_with_dependency};

let (s_b, r_b) = new_channel(None);
let (s_a, r_a) = new_channel_with_dependency(None, &s_b, &r_b);

s_a.send(0).unwrap();

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

assert_eq!(r_b.recv(), Ok(1)); // Received immediately.
assert_eq!(r_b.recv(), Ok(2)); // Received after 1 second.
assert_eq!(r_b.recv(), Err(RecvError)); // All `B` senders have been dropped

// Channel `B` is disconnected, channel `A` disconnects as well
assert_eq!(s_a.send(3), Err(SendError(3)));
assert_eq!(r_a.recv(), Ok(0));
assert_eq!(r_a.recv(), Err(RecvError));

Implementations§

Source §

impl<T> Receiver<T>

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::RecvError;
use lambda_channel::channel::new_channel;

let (s, r) = new_channel(None);

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 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::TryRecvError;
use lambda_channel::channel::new_channel;

let (s, r) = new_channel(None);
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_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::RecvTimeoutError;
use lambda_channel::channel::new_channel;

let (s, r) = new_channel(None);

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::RecvTimeoutError;
use lambda_channel::channel::new_channel;

let (s, r) = new_channel(None);

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 lambda_channel::channel::new_channel;

let (s, r) = new_channel(None);

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 lambda_channel::channel::new_channel;

let (s, r) = new_channel(Some(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 lambda_channel::channel::new_channel;

let (s, r) = new_channel(None);
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>

Returns the channel’s capacity.

§Examples

use lambda_channel::channel::new_channel;

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

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

let (_, r) = new_channel::<i32>(Some(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 lambda_channel::channel::new_channel;

let (s, r) = new_channel(None);

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 lambda_channel::channel::new_channel;

let (s, r) = new_channel::<i32>(None);

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 lambda_channel::channel::new_channel;

let (_, r) = new_channel::<usize>(None);

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

let (_, r3) = new_channel(None);
assert!(!r.same_channel(&r3));