Struct thingbuf::mpsc::blocking::Receiver

pub struct Receiver<T, R = DefaultRecycle> { /* private fields */ }

Available on crate feature std only.

Synchronously sends values to an associated Receiver.

Instances of this struct are created by the channel and with_recycle functions.

Implementations

impl<T, R> Receiver<T, R>

pub fn recv_ref(&self) -> Option<RecvRef<'_, T>>

Receives the next message for this receiver, by reference.

This method returns None if the channel has been closed and there are no remaining messages in the channel’s buffer. This indicates that no further values can ever be received from this Receiver. The channel is closed when all Senders have been dropped.

If there are no messages in the channel’s buffer, but the channel has not yet been closed, this method will block until a message is sent or the channel is closed.

This method returns a RecvRef that can be used to read from (or mutate) the received message by reference. When the RecvRef is dropped, the receive operation completes and the slot occupied by the received message becomes usable for a future send_ref operation.

If all Senders for this channel write to the channel’s slots in place by using the send_ref or try_send_ref methods, this method allows messages that own heap allocations to be reused in place.

Examples

use thingbuf::mpsc::blocking;
use std::{thread, fmt::Write};

let (tx, rx) = blocking::channel::<String>(100);

thread::spawn(move || {
    let mut value = tx.send_ref().unwrap();
    write!(value, "hello world!")
        .expect("writing to a `String` should never fail");
});

assert_eq!(Some("hello world!"), rx.recv_ref().as_deref().map(String::as_str));
assert_eq!(None, rx.recv().as_deref());

Values are buffered:

use thingbuf::mpsc::blocking;
use std::fmt::Write;

let (tx, rx) = blocking::channel::<String>(100);

write!(tx.send_ref().unwrap(), "hello").unwrap();
write!(tx.send_ref().unwrap(), "world").unwrap();

assert_eq!("hello", rx.recv_ref().unwrap().as_str());
assert_eq!("world", rx.recv_ref().unwrap().as_str());

pub fn recv(&self) -> Option<T>

where R: Recycle<T>,

Receives the next message for this receiver, by value.

This method returns None if the channel has been closed and there are no remaining messages in the channel’s buffer. This indicates that no further values can ever be received from this Receiver. The channel is closed when all Senders have been dropped.

If there are no messages in the channel’s buffer, but the channel has not yet been closed, this method will block until a message is sent or the channel is closed.

When a message is received, it is moved out of the channel by value, and replaced with a new slot according to the configured recycling policy. If all Senders for this channel write to the channel’s slots in place by using the send_ref or try_send_ref methods, consider using the recv_ref method instead, to enable the reuse of heap allocations.

Examples

use thingbuf::mpsc::blocking;
use std::{thread, fmt::Write};

let (tx, rx) = blocking::channel(100);

thread::spawn(move || {
   tx.send(1).unwrap();
});

assert_eq!(Some(1), rx.recv());
assert_eq!(None, rx.recv());

Values are buffered:

use thingbuf::mpsc::blocking;

let (tx, rx) = blocking::channel(100);

tx.send(1).unwrap();
tx.send(2).unwrap();

assert_eq!(Some(1), rx.recv());
assert_eq!(Some(2), rx.recv());

pub fn recv_ref_timeout( &self, timeout: Duration ) -> Result<RecvRef<'_, T>, RecvTimeoutError>

Available on non-loom only.

Receives the next message for this receiver, by reference, waiting for at most timeout.

If there are no messages in the channel’s buffer, but the channel has not yet been closed, this method will block until a message is sent, the channel is closed, or the provided timeout has elapsed.

Returns

• Ok(RecvRef<T>) if a message was received.
• Err(RecvTimeoutError::Timeout) if the timeout has elapsed.
• Err(RecvTimeoutError::Closed) if the channel has closed.

Examples

use thingbuf::mpsc::{blocking, errors::RecvTimeoutError};
use std::{thread, fmt::Write, time::Duration};

let (tx, rx) = blocking::channel::<String>(100);

thread::spawn(move || {
    thread::sleep(Duration::from_millis(600));
    let mut value = tx.send_ref().unwrap();
    write!(value, "hello world!")
        .expect("writing to a `String` should never fail");
});

assert_eq!(
    Err(&RecvTimeoutError::Timeout),
    rx.recv_ref_timeout(Duration::from_millis(400)).as_deref().map(String::as_str)
);
assert_eq!(
    Ok("hello world!"),
    rx.recv_ref_timeout(Duration::from_millis(400)).as_deref().map(String::as_str)
);
assert_eq!(
    Err(&RecvTimeoutError::Closed),
    rx.recv_ref_timeout(Duration::from_millis(400)).as_deref().map(String::as_str)
);

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

where R: Recycle<T>,

Available on non-loom only.

Receives the next message for this receiver, by value, waiting for at most timeout.

If there are no messages in the channel’s buffer, but the channel has not yet been closed, this method will block until a message is sent, the channel is closed, or the provided timeout has elapsed.

When a message is received, it is moved out of the channel by value, and replaced with a new slot according to the configured recycling policy. If all Senders for this channel write to the channel’s slots in place by using the send_ref or try_send_ref methods, consider using the recv_ref_timeout method instead, to enable the reuse of heap allocations.

Returns

• Ok(<T>) if a message was received.
• Err(RecvTimeoutError::Timeout) if the timeout has elapsed.
• Err(RecvTimeoutError::Closed) if the channel has closed.

Examples

use thingbuf::mpsc::{blocking, errors::RecvTimeoutError};
use std::{thread, fmt::Write, time::Duration};

let (tx, rx) = blocking::channel(100);

thread::spawn(move || {
   thread::sleep(Duration::from_millis(600));
   tx.send(1).unwrap();
});

assert_eq!(
    Err(RecvTimeoutError::Timeout),
    rx.recv_timeout(Duration::from_millis(400))
);
assert_eq!(
    Ok(1),
    rx.recv_timeout(Duration::from_millis(400))
);
assert_eq!(
    Err(RecvTimeoutError::Closed),
    rx.recv_timeout(Duration::from_millis(400))
);

pub fn try_recv_ref(&self) -> Result<RecvRef<'_, T>, TryRecvError>

Attempts to receive the next message for this receiver by reference without blocking.

This method differs from recv_ref by returning immediately if the channel is empty or closed.

Errors

This method returns an error when the channel is closed or there are no remaining messages in the channel’s buffer.

Examples

use thingbuf::mpsc::{blocking, errors::TryRecvError};

let (tx, rx) = blocking::channel(100);
assert!(matches!(rx.try_recv_ref(), Err(TryRecvError::Empty)));

tx.send(1).unwrap();
drop(tx);

assert_eq!(*rx.try_recv_ref().unwrap(), 1);
assert!(matches!(rx.try_recv_ref(), Err(TryRecvError::Closed)));

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

where R: Recycle<T>,

Attempts to receive the next message for this receiver by value without blocking.

This method differs from recv by returning immediately if the channel is empty or closed.

Errors

This method returns an error when the channel is closed or there are no remaining messages in the channel’s buffer.

Examples

use thingbuf::mpsc::{blocking, errors::TryRecvError};

let (tx, rx) = blocking::channel(100);
assert_eq!(rx.try_recv(), Err(TryRecvError::Empty));

tx.send(1).unwrap();
drop(tx);

assert_eq!(rx.try_recv().unwrap(), 1);
assert_eq!(rx.try_recv(), Err(TryRecvError::Closed));

pub fn is_closed(&self) -> bool

Returns true if the channel has closed (all corresponding Senders have been dropped).

If this method returns true, no new messages will become available on this channel. Previously sent messages may still be available.

pub fn capacity(&self) -> usize

Returns the total capacity of the channel for this Receiver. This includes both occupied and unoccupied entries.

To determine the channel’s remaining unoccupied capacity, use remaining instead.

Examples

use thingbuf::mpsc::blocking::channel;

let (_, rx) = channel::<usize>(100);
assert_eq!(rx.capacity(), 100);

Even after sending several messages, the capacity remains the same:

let (tx, rx) = channel::<usize>(100);
*tx.try_send_ref().unwrap() = 1;
*tx.try_send_ref().unwrap() = 2;
*tx.try_send_ref().unwrap() = 3;

assert_eq!(rx.capacity(), 100);

pub fn remaining(&self) -> usize

Returns the unoccupied capacity of the channel for this Receiver (i.e., how many additional elements can be sent before the channel will be full).

This is equivalent to subtracting the channel’s len from its capacity.

Examples

use thingbuf::mpsc::blocking::channel;

let (tx, rx) = channel::<usize>(100);
assert_eq!(rx.remaining(), 100);

*tx.try_send_ref().unwrap() = 1;
*tx.try_send_ref().unwrap() = 2;
*tx.try_send_ref().unwrap() = 3;
assert_eq!(rx.remaining(), 97);

let _ = rx.try_recv_ref().unwrap();
assert_eq!(rx.remaining(), 98)

pub fn len(&self) -> usize

Returns the number of elements in the channel of this Receiver.

To determine the channel’s remaining unoccupied capacity, use remaining instead.

Examples

use thingbuf::mpsc::blocking::channel;

let (tx, rx) = channel::<usize>(100);
assert_eq!(rx.len(), 0);

*tx.try_send_ref().unwrap() = 1;
*tx.try_send_ref().unwrap() = 2;
*tx.try_send_ref().unwrap() = 3;
assert_eq!(rx.len(), 3);

let _ = rx.try_recv_ref().unwrap();
assert_eq!(rx.len(), 2);

pub fn is_empty(&self) -> bool

Returns whether the number of elements in the channel of this Receiver is 0.

Examples

use thingbuf::mpsc::channel;
let (tx, rx) = channel::<usize>(100);
assert!(rx.is_empty());

*tx.try_send_ref().unwrap() = 1;

assert!(!rx.is_empty());

Trait Implementations

impl<T: Debug, R: Debug> Debug for Receiver<T, R>

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

Formats the value using the given formatter.

impl<T, R> Drop for Receiver<T, R>

fn drop(&mut self)

Executes the destructor for this type.

impl<'a, T, R> Iterator for &'a Receiver<T, R>

type Item = RecvRef<'a, T>

The type of the elements being iterated over.

fn next(&mut self) -> Option<Self::Item>

Advances the iterator and returns the next value.

fn next_chunk<const N: usize>( &mut self ) -> Result<[Self::Item; N], IntoIter<Self::Item, N>>

where Self: Sized,

🔬This is a nightly-only experimental API. (iter_next_chunk)

Advances the iterator and returns an array containing the next N values.

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the iterator.

fn count(self) -> usize

where Self: Sized,

Consumes the iterator, counting the number of iterations and returning it.

fn last(self) -> Option<Self::Item>

where Self: Sized,

Consumes the iterator, returning the last element.

fn advance_by(&mut self, n: usize) -> Result<(), NonZero<usize>>

🔬This is a nightly-only experimental API. (iter_advance_by)

Advances the iterator by n elements.

fn nth(&mut self, n: usize) -> Option<Self::Item>

Returns the nth element of the iterator.

fn step_by(self, step: usize) -> StepBy<Self>

where Self: Sized,

Creates an iterator starting at the same point, but stepping by the given amount at each iteration.

fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter>

where Self: Sized, U: IntoIterator<Item = Self::Item>,

Takes two iterators and creates a new iterator over both in sequence.

fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter>

where Self: Sized, U: IntoIterator,

‘Zips up’ two iterators into a single iterator of pairs.

fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>

where Self: Sized, G: FnMut() -> Self::Item,

🔬This is a nightly-only experimental API. (iter_intersperse)

Creates a new iterator which places an item generated by separator between adjacent items of the original iterator.

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

where Self: Sized, F: FnMut(Self::Item) -> B,

Takes a closure and creates an iterator which calls that closure on each element.

fn for_each<F>(self, f: F)

where Self: Sized, F: FnMut(Self::Item),

Calls a closure on each element of an iterator.

fn filter<P>(self, predicate: P) -> Filter<Self, P>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator which uses a closure to determine if an element should be yielded.

fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>

where Self: Sized, F: FnMut(Self::Item) -> Option<B>,

Creates an iterator that both filters and maps.

fn enumerate(self) -> Enumerate<Self>

where Self: Sized,

Creates an iterator which gives the current iteration count as well as the next value.

fn peekable(self) -> Peekable<Self>

where Self: Sized,

Creates an iterator which can use the peek and peek_mut methods to look at the next element of the iterator without consuming it. See their documentation for more information.

fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator that skips elements based on a predicate.

fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator that yields elements based on a predicate.

fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>

where Self: Sized, P: FnMut(Self::Item) -> Option<B>,

Creates an iterator that both yields elements based on a predicate and maps.

fn skip(self, n: usize) -> Skip<Self>

where Self: Sized,

Creates an iterator that skips the first n elements.

fn take(self, n: usize) -> Take<Self>

where Self: Sized,

Creates an iterator that yields the first n elements, or fewer if the underlying iterator ends sooner.

fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>

where Self: Sized, F: FnMut(&mut St, Self::Item) -> Option<B>,

An iterator adapter which, like fold, holds internal state, but unlike fold, produces a new iterator.

fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>

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

Creates an iterator that works like map, but flattens nested structure.

fn map_windows<F, R, const N: usize>(self, f: F) -> MapWindows<Self, F, N>

where Self: Sized, F: FnMut(&[Self::Item; N]) -> R,

🔬This is a nightly-only experimental API. (iter_map_windows)

Calls the given function f for each contiguous window of size N over self and returns an iterator over the outputs of f. Like slice::windows(), the windows during mapping overlap as well.

fn fuse(self) -> Fuse<Self>

where Self: Sized,

Creates an iterator which ends after the first None.

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

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

Does something with each element of an iterator, passing the value on.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Borrows an iterator, rather than consuming it.

fn collect<B>(self) -> B

where B: FromIterator<Self::Item>, Self: Sized,

Transforms an iterator into a collection.

fn collect_into<E>(self, collection: &mut E) -> &mut E

where E: Extend<Self::Item>, Self: Sized,

🔬This is a nightly-only experimental API. (iter_collect_into)

Collects all the items from an iterator into a collection.

fn partition<B, F>(self, f: F) -> (B, B)

where Self: Sized, B: Default + Extend<Self::Item>, F: FnMut(&Self::Item) -> bool,

Consumes an iterator, creating two collections from it.

fn is_partitioned<P>(self, predicate: P) -> bool

where Self: Sized, P: FnMut(Self::Item) -> bool,

🔬This is a nightly-only experimental API. (iter_is_partitioned)

Checks if the elements of this iterator are partitioned according to the given predicate, such that all those that return true precede all those that return false.

fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R

where Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Output = B>,

An iterator method that applies a function as long as it returns successfully, producing a single, final value.

fn try_for_each<F, R>(&mut self, f: F) -> R

where Self: Sized, F: FnMut(Self::Item) -> R, R: Try<Output = ()>,

An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error.

fn fold<B, F>(self, init: B, f: F) -> B

where Self: Sized, F: FnMut(B, Self::Item) -> B,

Folds every element into an accumulator by applying an operation, returning the final result.

fn reduce<F>(self, f: F) -> Option<Self::Item>

where Self: Sized, F: FnMut(Self::Item, Self::Item) -> Self::Item,

Reduces the elements to a single one, by repeatedly applying a reducing operation.

fn try_reduce<F, R>( &mut self, f: F ) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryType

where Self: Sized, F: FnMut(Self::Item, Self::Item) -> R, R: Try<Output = Self::Item>, <R as Try>::Residual: Residual<Option<Self::Item>>,

🔬This is a nightly-only experimental API. (iterator_try_reduce)

Reduces the elements to a single one by repeatedly applying a reducing operation. If the closure returns a failure, the failure is propagated back to the caller immediately.

fn all<F>(&mut self, f: F) -> bool

where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if every element of the iterator matches a predicate.

fn any<F>(&mut self, f: F) -> bool

where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if any element of the iterator matches a predicate.

fn find<P>(&mut self, predicate: P) -> Option<Self::Item>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Searches for an element of an iterator that satisfies a predicate.

fn find_map<B, F>(&mut self, f: F) -> Option<B>

where Self: Sized, F: FnMut(Self::Item) -> Option<B>,

Applies function to the elements of iterator and returns the first non-none result.

fn try_find<F, R>( &mut self, f: F ) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryType

where Self: Sized, F: FnMut(&Self::Item) -> R, R: Try<Output = bool>, <R as Try>::Residual: Residual<Option<Self::Item>>,

🔬This is a nightly-only experimental API. (try_find)

Applies function to the elements of iterator and returns the first true result or the first error.

fn position<P>(&mut self, predicate: P) -> Option<usize>

where Self: Sized, P: FnMut(Self::Item) -> bool,

Searches for an element in an iterator, returning its index.

fn max_by_key<B, F>(self, f: F) -> Option<Self::Item>

where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the maximum value from the specified function.

fn max_by<F>(self, compare: F) -> Option<Self::Item>

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the maximum value with respect to the specified comparison function.

fn min_by_key<B, F>(self, f: F) -> Option<Self::Item>

where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the minimum value from the specified function.

fn min_by<F>(self, compare: F) -> Option<Self::Item>

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the minimum value with respect to the specified comparison function.

fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)

where FromA: Default + Extend<A>, FromB: Default + Extend<B>, Self: Sized + Iterator<Item = (A, B)>,

Converts an iterator of pairs into a pair of containers.

fn copied<'a, T>(self) -> Copied<Self>

where T: 'a + Copy, Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which copies all of its elements.

fn cloned<'a, T>(self) -> Cloned<Self>

where T: 'a + Clone, Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which clones all of its elements.

fn cycle(self) -> Cycle<Self>

where Self: Sized + Clone,

Repeats an iterator endlessly.

fn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N>

where Self: Sized,

🔬This is a nightly-only experimental API. (iter_array_chunks)

Returns an iterator over N elements of the iterator at a time.

fn sum<S>(self) -> S

where Self: Sized, S: Sum<Self::Item>,

Sums the elements of an iterator.

fn product<P>(self) -> P

where Self: Sized, P: Product<Self::Item>,

Iterates over the entire iterator, multiplying all the elements

fn cmp_by<I, F>(self, other: I, cmp: F) -> Ordering

where Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Ordering,

🔬This is a nightly-only experimental API. (iter_order_by)

Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function.

fn partial_cmp<I>(self, other: I) -> Option<Ordering>

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Lexicographically compares the PartialOrd elements of this Iterator with those of another. The comparison works like short-circuit evaluation, returning a result without comparing the remaining elements. As soon as an order can be determined, the evaluation stops and a result is returned.

fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering>

where Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Option<Ordering>,

🔬This is a nightly-only experimental API. (iter_order_by)

Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function.

fn eq<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialEq<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are equal to those of another.

fn eq_by<I, F>(self, other: I, eq: F) -> bool

where Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::Item) -> bool,

🔬This is a nightly-only experimental API. (iter_order_by)

Determines if the elements of this Iterator are equal to those of another with respect to the specified equality function.

fn ne<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialEq<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are not equal to those of another.

fn lt<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically less than those of another.

fn le<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically less or equal to those of another.

fn gt<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically greater than those of another.

fn ge<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically greater than or equal to those of another.

fn is_sorted_by<F>(self, compare: F) -> bool

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> bool,

🔬This is a nightly-only experimental API. (is_sorted)

Checks if the elements of this iterator are sorted using the given comparator function.

fn is_sorted_by_key<F, K>(self, f: F) -> bool

where Self: Sized, F: FnMut(Self::Item) -> K, K: PartialOrd,

🔬This is a nightly-only experimental API. (is_sorted)

Checks if the elements of this iterator are sorted using the given key extraction function.