diff --git a/src/sync/channel.rs b/src/sync/channel.rs index a957bec9..ff9f9961 100644 --- a/src/sync/channel.rs +++ b/src/sync/channel.rs @@ -1,5 +1,6 @@ use std::cell::UnsafeCell; -use std::fmt; +use std::error::Error; +use std::fmt::{Debug, Display, self}; use std::future::Future; use std::isize; use std::marker::PhantomData; @@ -192,6 +193,27 @@ impl Sender { .await } + /// Attempts to send a message into the channel. + /// + /// If the channel is full, this method will return an error. + /// + /// # Examples + /// + /// ``` + /// # async_std::task::block_on(async { + /// # + /// use async_std::sync::channel; + /// + /// let (s, r) = channel(1); + /// assert!(s.try_send(1).is_ok()); + /// assert!(s.try_send(2).is_err()); + /// # + /// # }) + /// ``` + pub fn try_send(&self, msg: T) -> Result<(), TrySendError> { + self.channel.try_send(msg) + } + /// Returns the channel capacity. /// /// # Examples @@ -409,6 +431,30 @@ impl Receiver { .await } + /// Attempts to receive a message from the channel. + /// + /// If the channel is empty, this method will return an error. + /// + /// # Examples + /// + /// ``` + /// # async_std::task::block_on(async { + /// # + /// use async_std::sync::channel; + /// + /// let (s, r) = channel(1); + /// + /// s.send(1u8).await; + /// + /// assert!(r.try_recv().is_ok()); + /// assert!(r.try_recv().is_err()); + /// # + /// # }) + /// ``` + pub fn try_recv(&self) -> Result { + self.channel.try_recv() + } + /// Returns the channel capacity. /// /// # Examples @@ -936,8 +982,8 @@ impl Drop for Channel { } } -/// An error returned from the `try_send()` method. -enum TrySendError { +/// An error returned from the `try_send` method. +pub enum TrySendError { /// The channel is full but not disconnected. Full(T), @@ -945,11 +991,43 @@ enum TrySendError { Disconnected(T), } -/// An error returned from the `try_recv()` method. -enum TryRecvError { +impl Error for TrySendError {} + +impl Debug for TrySendError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + match self { + Self::Full(_) => Debug::fmt("Full", f), + Self::Disconnected(_) => Debug::fmt("Disconnected", f), + } + } +} + +impl Display for TrySendError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + match self { + Self::Full(_) => Display::fmt("The channel is full.", f), + Self::Disconnected(_) => Display::fmt("The channel is full and disconnected.", f), + } + } +} + +/// An error returned from the `try_recv` method. +#[derive(Debug)] +pub enum TryRecvError { /// The channel is empty but not disconnected. Empty, /// The channel is empty and disconnected. Disconnected, } + +impl Error for TryRecvError {} + +impl Display for TryRecvError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + match self { + Self::Empty => Display::fmt("The channel is empty.", f), + Self::Disconnected => Display::fmt("The channel is empty and disconnected.", f), + } + } +} diff --git a/src/sync/mod.rs b/src/sync/mod.rs index 088c520b..1d6a93f5 100644 --- a/src/sync/mod.rs +++ b/src/sync/mod.rs @@ -184,7 +184,7 @@ mod rwlock; cfg_unstable! { pub use barrier::{Barrier, BarrierWaitResult}; - pub use channel::{channel, Sender, Receiver}; + pub use channel::{channel, Sender, Receiver, TryRecvError, TrySendError}; mod barrier; mod channel;