diff --git a/src/libstd/sync/mpsc/mod.rs b/src/libstd/sync/mpsc/mod.rs index 71dd94161c03d..0da65a4f2e12f 100644 --- a/src/libstd/sync/mpsc/mod.rs +++ b/src/libstd/sync/mpsc/mod.rs @@ -13,40 +13,50 @@ //! This module provides message-based communication over channels, concretely //! defined among three types: //! -//! * `Sender` -//! * `SyncSender` -//! * `Receiver` +//! * [`Sender`] +//! * [`SyncSender`] +//! * [`Receiver`] //! -//! A `Sender` or `SyncSender` is used to send data to a `Receiver`. Both +//! A [`Sender`] or [`SyncSender`] is used to send data to a [`Receiver`]. Both //! senders are clone-able (multi-producer) such that many threads can send //! simultaneously to one receiver (single-consumer). //! //! These channels come in two flavors: //! -//! 1. An asynchronous, infinitely buffered channel. The `channel()` function +//! 1. An asynchronous, infinitely buffered channel. The [`channel`] function //! will return a `(Sender, Receiver)` tuple where all sends will be //! **asynchronous** (they never block). The channel conceptually has an //! infinite buffer. //! -//! 2. A synchronous, bounded channel. The `sync_channel()` function will return -//! a `(SyncSender, Receiver)` tuple where the storage for pending messages -//! is a pre-allocated buffer of a fixed size. All sends will be +//! 2. A synchronous, bounded channel. The [`sync_channel`] function will +//! return a `(SyncSender, Receiver)` tuple where the storage for pending +//! messages is a pre-allocated buffer of a fixed size. All sends will be //! **synchronous** by blocking until there is buffer space available. Note -//! that a bound of 0 is allowed, causing the channel to become a -//! "rendezvous" channel where each sender atomically hands off a message to -//! a receiver. +//! that a bound of 0 is allowed, causing the channel to become a "rendezvous" +//! channel where each sender atomically hands off a message to a receiver. +//! +//! [`Sender`]: ../../../std/sync/mpsc/struct.Sender.html +//! [`SyncSender`]: ../../../std/sync/mpsc/struct.SyncSender.html +//! [`Receiver`]: ../../../std/sync/mpsc/struct.Receiver.html +//! [`send`]: ../../../std/sync/mpsc/struct.Sender.html#method.send +//! [`channel`]: ../../../std/sync/mpsc/fn.channel.html +//! [`sync_channel`]: ../../../std/sync/mpsc/fn.sync_channel.html //! //! ## Disconnection //! -//! The send and receive operations on channels will all return a `Result` +//! The send and receive operations on channels will all return a [`Result`] //! indicating whether the operation succeeded or not. An unsuccessful operation //! is normally indicative of the other half of a channel having "hung up" by //! being dropped in its corresponding thread. //! //! Once half of a channel has been deallocated, most operations can no longer -//! continue to make progress, so `Err` will be returned. Many applications will -//! continue to `unwrap()` the results returned from this module, instigating a -//! propagation of failure among threads if one unexpectedly dies. +//! continue to make progress, so [`Err`] will be returned. Many applications +//! will continue to [`unwrap`] the results returned from this module, +//! instigating a propagation of failure among threads if one unexpectedly dies. +//! +//! [`Result`]: ../../../std/result/enum.Result.html +//! [`Err`]: ../../../std/result/enum.Result.html#variant.Err +//! [`unwrap`]: ../../../std/result/enum.Result.html#method.unwrap //! //! # Examples //! @@ -288,7 +298,31 @@ mod mpsc_queue; mod spsc_queue; /// The receiving-half of Rust's channel type. This half can only be owned by -/// one thread +/// one thread. +/// +/// Messages sent to the channel can be retrieved using [`recv`]. +/// +/// [`recv`]: ../../../std/sync/mpsc/struct.Receiver.html#method.recv +/// +/// # Examples +/// +/// ```rust +/// use std::sync::mpsc::channel; +/// use std::thread; +/// use std::time::Duration; +/// +/// let (send, recv) = channel(); +/// +/// thread::spawn(move || { +/// send.send("Hello world!").unwrap(); +/// thread::sleep(Duration::from_secs(2)); // block for two seconds +/// send.send("Delayed for 2 seconds").unwrap(); +/// }); +/// +/// println!("{}", recv.recv().unwrap()); // Received immediately +/// println!("Waiting..."); +/// println!("{}", recv.recv().unwrap()); // Received after 2 seconds +/// ``` #[stable(feature = "rust1", since = "1.0.0")] pub struct Receiver { inner: UnsafeCell>, @@ -302,9 +336,12 @@ unsafe impl Send for Receiver { } #[stable(feature = "rust1", since = "1.0.0")] impl !Sync for Receiver { } -/// An iterator over messages on a receiver, this iterator will block -/// whenever `next` is called, waiting for a new message, and `None` will be -/// returned when the corresponding channel has hung up. +/// An iterator over messages on a receiver, this iterator will block whenever +/// [`next`] is called, waiting for a new message, and [`None`] will be returned +/// when the corresponding channel has hung up. +/// +/// [`next`]: ../../../std/iter/trait.Iterator.html#tymethod.next +/// [`None`]: ../../../std/option/enum.Option.html#variant.None #[stable(feature = "rust1", since = "1.0.0")] #[derive(Debug)] pub struct Iter<'a, T: 'a> { @@ -312,11 +349,13 @@ pub struct Iter<'a, T: 'a> { } /// An iterator that attempts to yield all pending values for a receiver. -/// `None` will be returned when there are no pending values remaining or -/// if the corresponding channel has hung up. +/// [`None`] will be returned when there are no pending values remaining or if +/// the corresponding channel has hung up. /// /// This Iterator will never block the caller in order to wait for data to -/// become available. Instead, it will return `None`. +/// become available. Instead, it will return [`None`]. +/// +/// [`None`]: ../../../std/option/enum.Option.html#variant.None #[stable(feature = "receiver_try_iter", since = "1.15.0")] #[derive(Debug)] pub struct TryIter<'a, T: 'a> { @@ -324,8 +363,12 @@ pub struct TryIter<'a, T: 'a> { } /// An owning iterator over messages on a receiver, this iterator will block -/// whenever `next` is called, waiting for a new message, and `None` will be +/// whenever [`next`] is called, waiting for a new message, and [`None`] will be /// returned when the corresponding channel has hung up. +/// +/// [`next`]: ../../../std/iter/trait.Iterator.html#tymethod.next +/// [`None`]: ../../../std/option/enum.Option.html#variant.None +/// #[stable(feature = "receiver_into_iter", since = "1.1.0")] #[derive(Debug)] pub struct IntoIter { @@ -334,6 +377,35 @@ pub struct IntoIter { /// The sending-half of Rust's asynchronous channel type. This half can only be /// owned by one thread, but it can be cloned to send to other threads. +/// +/// Messages can be sent through this channel with [`send`]. +/// +/// [`send`]: ../../../std/sync/mpsc/struct.Sender.html#method.send +/// +/// # Examples +/// +/// ```rust +/// use std::sync::mpsc::channel; +/// use std::thread; +/// +/// let (sender, receiver) = channel(); +/// let sender2 = sender.clone(); +/// +/// // First thread owns sender +/// thread::spawn(move || { +/// sender.send(1).unwrap(); +/// }); +/// +/// // Second thread owns sender2 +/// thread::spawn(move || { +/// sender2.send(2).unwrap(); +/// }); +/// +/// let msg = receiver.recv().unwrap(); +/// let msg2 = receiver.recv().unwrap(); +/// +/// assert_eq!(3, msg + msg2); +/// ``` #[stable(feature = "rust1", since = "1.0.0")] pub struct Sender { inner: UnsafeCell>, @@ -349,6 +421,10 @@ impl !Sync for Sender { } /// The sending-half of Rust's synchronous channel type. This half can only be /// owned by one thread, but it can be cloned to send to other threads. +/// +/// [`send`]: ../../../std/sync/mpsc/struct.Sender.html#method.send +/// [`SyncSender::send`]: ../../../std/sync/mpsc/struct.SyncSender.html#method.send +/// #[stable(feature = "rust1", since = "1.0.0")] pub struct SyncSender { inner: Arc>, @@ -360,25 +436,32 @@ unsafe impl Send for SyncSender {} #[stable(feature = "rust1", since = "1.0.0")] impl !Sync for SyncSender {} -/// An error returned from the `send` function on channels. +/// An error returned from the [`send`] function on channels. /// -/// A `send` operation can only fail if the receiving end of a channel is +/// A [`send`] operation can only fail if the receiving end of a channel is /// disconnected, implying that the data could never be received. The error /// contains the data being sent as a payload so it can be recovered. +/// +/// [`send`]: ../../../std/sync/mpsc/struct.Sender.html#method.send #[stable(feature = "rust1", since = "1.0.0")] #[derive(PartialEq, Eq, Clone, Copy)] pub struct SendError(#[stable(feature = "rust1", since = "1.0.0")] pub T); -/// An error returned from the `recv` function on a `Receiver`. +/// An error returned from the [`recv`] function on a [`Receiver`]. /// -/// The `recv` operation can only fail if the sending half of a channel is +/// The [`recv`] operation can only fail if the sending half of a channel is /// disconnected, implying that no further messages will ever be received. +/// +/// [`recv`]: ../../../std/sync/mpsc/struct.Receiver.html#method.recv +/// [`Receiver`]: ../../../std/sync/mpsc/struct.Receiver.html #[derive(PartialEq, Eq, Clone, Copy, Debug)] #[stable(feature = "rust1", since = "1.0.0")] pub struct RecvError; -/// This enumeration is the list of the possible reasons that `try_recv` could +/// This enumeration is the list of the possible reasons that [`try_recv`] could /// not return data when called. +/// +/// [`try_recv`]: ../../../std/sync/mpsc/struct.Receiver.html#method.try_recv #[derive(PartialEq, Eq, Clone, Copy, Debug)] #[stable(feature = "rust1", since = "1.0.0")] pub enum TryRecvError { @@ -393,8 +476,10 @@ pub enum TryRecvError { Disconnected, } -/// This enumeration is the list of possible errors that `recv_timeout` could +/// This enumeration is the list of possible errors that [`recv_timeout`] could /// not return data when called. +/// +/// [`recv_timeout`]: ../../../std/sync/mpsc/struct.Receiver.html#method.recv_timeout #[derive(PartialEq, Eq, Clone, Copy, Debug)] #[stable(feature = "mpsc_recv_timeout", since = "1.12.0")] pub enum RecvTimeoutError { @@ -409,7 +494,9 @@ pub enum RecvTimeoutError { } /// This enumeration is the list of the possible error outcomes for the -/// `SyncSender::try_send` method. +/// [`SyncSender::try_send`] method. +/// +/// [`SyncSender::try_send`]: ../../../std/sync/mpsc/struct.SyncSender.html#method.try_send #[stable(feature = "rust1", since = "1.0.0")] #[derive(PartialEq, Eq, Clone, Copy)] pub enum TrySendError { @@ -556,10 +643,13 @@ impl Sender { /// A successful send occurs when it is determined that the other end of /// the channel has not hung up already. An unsuccessful send would be one /// where the corresponding receiver has already been deallocated. Note - /// that a return value of `Err` means that the data will never be - /// received, but a return value of `Ok` does *not* mean that the data + /// that a return value of [`Err`] means that the data will never be + /// received, but a return value of [`Ok`] does *not* mean that the data /// will be received. It is possible for the corresponding receiver to - /// hang up immediately after this function returns `Ok`. + /// hang up immediately after this function returns [`Ok`]. + /// + /// [`Err`]: ../../../std/result/enum.Result.html#variant.Err + /// [`Ok`]: ../../../std/result/enum.Result.html#variant.Ok /// /// This method will never block the current thread. /// @@ -702,9 +792,12 @@ impl SyncSender { /// time. If the buffer size is 0, however, it can be guaranteed that the /// receiver has indeed received the data if this function returns success. /// - /// This function will never panic, but it may return `Err` if the - /// `Receiver` has disconnected and is no longer able to receive + /// This function will never panic, but it may return [`Err`] if the + /// [`Receiver`] has disconnected and is no longer able to receive /// information. + /// + /// [`Err`]: ../../../std/result/enum.Result.html#variant.Err + /// [`Receiver`]: ../../../std/sync/mpsc/struct.Receiver.html #[stable(feature = "rust1", since = "1.0.0")] pub fn send(&self, t: T) -> Result<(), SendError> { self.inner.send(t).map_err(SendError) @@ -712,13 +805,16 @@ impl SyncSender { /// Attempts to send a value on this channel without blocking. /// - /// This method differs from `send` by returning immediately if the + /// This method differs from [`send`] by returning immediately if the /// channel's buffer is full or no receiver is waiting to acquire some - /// data. Compared with `send`, this function has two failure cases + /// data. Compared with [`send`], this function has two failure cases /// instead of one (one for disconnection, one for a full buffer). /// - /// See `SyncSender::send` for notes about guarantees of whether the + /// See [`SyncSender::send`] for notes about guarantees of whether the /// receiver has received the data or not if this function is successful. + /// + /// [`send`]: ../../../std/sync/mpsc/struct.Sender.html#method.send + /// [`SyncSender::send`]: ../../../std/sync/mpsc/struct.SyncSender.html#method.send #[stable(feature = "rust1", since = "1.0.0")] pub fn try_send(&self, t: T) -> Result<(), TrySendError> { self.inner.try_send(t) @@ -819,15 +915,18 @@ impl Receiver { /// /// This function will always block the current thread if there is no data /// available and it's possible for more data to be sent. Once a message is - /// sent to the corresponding `Sender`, then this receiver will wake up and + /// sent to the corresponding [`Sender`], then this receiver will wake up and /// return that message. /// - /// If the corresponding `Sender` has disconnected, or it disconnects while - /// this call is blocking, this call will wake up and return `Err` to + /// If the corresponding [`Sender`] has disconnected, or it disconnects while + /// this call is blocking, this call will wake up and return [`Err`] to /// indicate that no more messages can ever be received on this channel. /// However, since channels are buffered, messages sent before the disconnect /// will still be properly received. /// + /// [`Sender`]: ../../../std/sync/mpsc/struct.Sender.html + /// [`Err`]: ../../../std/result/enum.Result.html#variant.Err + /// /// # Examples /// /// ``` @@ -907,15 +1006,18 @@ impl Receiver { /// /// This function will always block the current thread if there is no data /// available and it's possible for more data to be sent. Once a message is - /// sent to the corresponding `Sender`, then this receiver will wake up and + /// sent to the corresponding [`Sender`], then this receiver will wake up and /// return that message. /// - /// If the corresponding `Sender` has disconnected, or it disconnects while - /// this call is blocking, this call will wake up and return `Err` to + /// If the corresponding [`Sender`] has disconnected, or it disconnects while + /// this call is blocking, this call will wake up and return [`Err`] to /// indicate that no more messages can ever be received on this channel. /// However, since channels are buffered, messages sent before the disconnect /// will still be properly received. /// + /// [`Sender`]: ../../../std/sync/mpsc/struct.Sender.html + /// [`Err`]: ../../../std/result/enum.Result.html#variant.Err + /// /// # Examples /// /// ```no_run @@ -993,7 +1095,29 @@ impl Receiver { } /// Returns an iterator that will block waiting for messages, but never - /// `panic!`. It will return `None` when the channel has hung up. + /// [`panic!`]. It will return [`None`] when the channel has hung up. + /// + /// [`panic!`]: ../../../std/macro.panic.html + /// [`None`]: ../../../std/option/enum.Option.html#variant.None + /// + /// # Examples + /// + /// ```rust + /// use std::sync::mpsc::channel; + /// use std::thread; + /// + /// let (send, recv) = channel(); + /// + /// thread::spawn(move || { + /// send.send(1u8).unwrap(); + /// send.send(2u8).unwrap(); + /// send.send(3u8).unwrap(); + /// }); + /// + /// for x in recv.iter() { + /// println!("Got: {}", x); + /// } + /// ``` #[stable(feature = "rust1", since = "1.0.0")] pub fn iter(&self) -> Iter { Iter { rx: self } @@ -1001,8 +1125,10 @@ impl Receiver { /// Returns an iterator that will attempt to yield all pending values. /// It will return `None` if there are no more pending values or if the - /// channel has hung up. The iterator will never `panic!` or block the + /// channel has hung up. The iterator will never [`panic!`] or block the /// user by waiting for values. + /// + /// [`panic!`]: ../../../std/macro.panic.html #[stable(feature = "receiver_try_iter", since = "1.15.0")] pub fn try_iter(&self) -> TryIter { TryIter { rx: self }