Vendor things
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743
third-party/vendor/mio/src/poll.rs
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third-party/vendor/mio/src/poll.rs
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#[cfg(all(
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unix,
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not(mio_unsupported_force_poll_poll),
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not(any(target_os = "solaris", target_os = "vita"))
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))]
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use std::os::unix::io::{AsRawFd, RawFd};
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#[cfg(all(debug_assertions, not(target_os = "wasi")))]
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use std::sync::atomic::{AtomicBool, Ordering};
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#[cfg(all(debug_assertions, not(target_os = "wasi")))]
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use std::sync::Arc;
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use std::time::Duration;
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use std::{fmt, io};
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use crate::{event, sys, Events, Interest, Token};
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/// Polls for readiness events on all registered values.
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///
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/// `Poll` allows a program to monitor a large number of [`event::Source`]s,
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/// waiting until one or more become "ready" for some class of operations; e.g.
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/// reading and writing. An event source is considered ready if it is possible
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/// to immediately perform a corresponding operation; e.g. [`read`] or
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/// [`write`].
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///
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/// To use `Poll`, an `event::Source` must first be registered with the `Poll`
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/// instance using the [`register`] method on its associated `Register`,
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/// supplying readiness interest. The readiness interest tells `Poll` which
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/// specific operations on the handle to monitor for readiness. A `Token` is
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/// also passed to the [`register`] function. When `Poll` returns a readiness
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/// event, it will include this token. This associates the event with the
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/// event source that generated the event.
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///
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/// [`event::Source`]: ./event/trait.Source.html
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/// [`read`]: ./net/struct.TcpStream.html#method.read
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/// [`write`]: ./net/struct.TcpStream.html#method.write
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/// [`register`]: struct.Registry.html#method.register
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///
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/// # Examples
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///
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/// A basic example -- establishing a `TcpStream` connection.
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///
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#[cfg_attr(all(feature = "os-poll", feature = "net"), doc = "```")]
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#[cfg_attr(not(all(feature = "os-poll", feature = "net")), doc = "```ignore")]
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/// # use std::error::Error;
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/// # fn main() -> Result<(), Box<dyn Error>> {
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/// use mio::{Events, Poll, Interest, Token};
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/// use mio::net::TcpStream;
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///
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/// use std::net::{self, SocketAddr};
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///
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/// // Bind a server socket to connect to.
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/// let addr: SocketAddr = "127.0.0.1:0".parse()?;
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/// let server = net::TcpListener::bind(addr)?;
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///
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/// // Construct a new `Poll` handle as well as the `Events` we'll store into
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/// let mut poll = Poll::new()?;
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/// let mut events = Events::with_capacity(1024);
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///
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/// // Connect the stream
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/// let mut stream = TcpStream::connect(server.local_addr()?)?;
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///
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/// // Register the stream with `Poll`
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/// poll.registry().register(&mut stream, Token(0), Interest::READABLE | Interest::WRITABLE)?;
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///
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/// // Wait for the socket to become ready. This has to happens in a loop to
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/// // handle spurious wakeups.
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/// loop {
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/// poll.poll(&mut events, None)?;
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///
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/// for event in &events {
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/// if event.token() == Token(0) && event.is_writable() {
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/// // The socket connected (probably, it could still be a spurious
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/// // wakeup)
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/// return Ok(());
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/// }
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/// }
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/// }
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/// # }
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/// ```
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///
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/// # Portability
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///
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/// Using `Poll` provides a portable interface across supported platforms as
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/// long as the caller takes the following into consideration:
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///
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/// ### Spurious events
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///
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/// [`Poll::poll`] may return readiness events even if the associated
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/// event source is not actually ready. Given the same code, this may
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/// happen more on some platforms than others. It is important to never assume
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/// that, just because a readiness event was received, that the associated
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/// operation will succeed as well.
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///
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/// If operation fails with [`WouldBlock`], then the caller should not treat
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/// this as an error, but instead should wait until another readiness event is
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/// received.
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///
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/// ### Draining readiness
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///
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/// Once a readiness event is received, the corresponding operation must be
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/// performed repeatedly until it returns [`WouldBlock`]. Unless this is done,
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/// there is no guarantee that another readiness event will be delivered, even
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/// if further data is received for the event source.
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///
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/// [`WouldBlock`]: std::io::ErrorKind::WouldBlock
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///
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/// ### Readiness operations
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///
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/// The only readiness operations that are guaranteed to be present on all
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/// supported platforms are [`readable`] and [`writable`]. All other readiness
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/// operations may have false negatives and as such should be considered
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/// **hints**. This means that if a socket is registered with [`readable`]
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/// interest and either an error or close is received, a readiness event will
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/// be generated for the socket, but it **may** only include `readable`
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/// readiness. Also note that, given the potential for spurious events,
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/// receiving a readiness event with `read_closed`, `write_closed`, or `error`
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/// doesn't actually mean that a `read` on the socket will return a result
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/// matching the readiness event.
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///
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/// In other words, portable programs that explicitly check for [`read_closed`],
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/// [`write_closed`], or [`error`] readiness should be doing so as an
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/// **optimization** and always be able to handle an error or close situation
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/// when performing the actual read operation.
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///
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/// [`readable`]: ./event/struct.Event.html#method.is_readable
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/// [`writable`]: ./event/struct.Event.html#method.is_writable
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/// [`error`]: ./event/struct.Event.html#method.is_error
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/// [`read_closed`]: ./event/struct.Event.html#method.is_read_closed
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/// [`write_closed`]: ./event/struct.Event.html#method.is_write_closed
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///
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/// ### Registering handles
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///
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/// Unless otherwise noted, it should be assumed that types implementing
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/// [`event::Source`] will never become ready unless they are registered with
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/// `Poll`.
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///
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/// For example:
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///
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#[cfg_attr(all(feature = "os-poll", feature = "net"), doc = "```")]
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#[cfg_attr(not(all(feature = "os-poll", feature = "net")), doc = "```ignore")]
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/// # use std::error::Error;
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/// # use std::net;
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/// # fn main() -> Result<(), Box<dyn Error>> {
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/// use mio::{Poll, Interest, Token};
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/// use mio::net::TcpStream;
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/// use std::net::SocketAddr;
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/// use std::time::Duration;
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/// use std::thread;
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///
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/// let address: SocketAddr = "127.0.0.1:0".parse()?;
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/// let listener = net::TcpListener::bind(address)?;
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/// let mut sock = TcpStream::connect(listener.local_addr()?)?;
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///
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/// thread::sleep(Duration::from_secs(1));
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///
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/// let poll = Poll::new()?;
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///
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/// // The connect is not guaranteed to have started until it is registered at
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/// // this point
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/// poll.registry().register(&mut sock, Token(0), Interest::READABLE | Interest::WRITABLE)?;
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/// # Ok(())
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/// # }
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/// ```
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///
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/// ### Dropping `Poll`
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///
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/// When the `Poll` instance is dropped it may cancel in-flight operations for
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/// the registered [event sources], meaning that no further events for them may
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/// be received. It also means operations on the registered event sources may no
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/// longer work. It is up to the user to keep the `Poll` instance alive while
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/// registered event sources are being used.
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///
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/// [event sources]: ./event/trait.Source.html
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///
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/// ### Accessing raw fd/socket/handle
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///
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/// Mio makes it possible for many types to be converted into a raw file
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/// descriptor (fd, Unix), socket (Windows) or handle (Windows). This makes it
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/// possible to support more operations on the type than Mio supports, for
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/// example it makes [mio-aio] possible. However accessing the raw fd is not
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/// without it's pitfalls.
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///
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/// Specifically performing I/O operations outside of Mio on these types (via
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/// the raw fd) has unspecified behaviour. It could cause no more events to be
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/// generated for the type even though it returned `WouldBlock` (in an operation
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/// directly accessing the fd). The behaviour is OS specific and Mio can only
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/// guarantee cross-platform behaviour if it can control the I/O.
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///
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/// [mio-aio]: https://github.com/asomers/mio-aio
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///
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/// *The following is **not** guaranteed, just a description of the current
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/// situation!* Mio is allowed to change the following without it being considered
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/// a breaking change, don't depend on this, it's just here to inform the user.
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/// Currently the kqueue and epoll implementation support direct I/O operations
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/// on the fd without Mio's knowledge. Windows however needs **all** I/O
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/// operations to go through Mio otherwise it is not able to update it's
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/// internal state properly and won't generate events.
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///
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/// ### Polling without registering event sources
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///
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///
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/// *The following is **not** guaranteed, just a description of the current
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/// situation!* Mio is allowed to change the following without it being
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/// considered a breaking change, don't depend on this, it's just here to inform
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/// the user. On platforms that use epoll, kqueue or IOCP (see implementation
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/// notes below) polling without previously registering [event sources] will
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/// result in sleeping forever, only a process signal will be able to wake up
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/// the thread.
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///
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/// On WASM/WASI this is different as it doesn't support process signals,
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/// furthermore the WASI specification doesn't specify a behaviour in this
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/// situation, thus it's up to the implementation what to do here. As an
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/// example, the wasmtime runtime will return `EINVAL` in this situation, but
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/// different runtimes may return different results. If you have further
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/// insights or thoughts about this situation (and/or how Mio should handle it)
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/// please add you comment to [pull request#1580].
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///
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/// [event sources]: crate::event::Source
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/// [pull request#1580]: https://github.com/tokio-rs/mio/pull/1580
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///
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/// # Implementation notes
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///
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/// `Poll` is backed by the selector provided by the operating system.
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///
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/// | OS | Selector |
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/// |---------------|-----------|
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/// | Android | [epoll] |
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/// | DragonFly BSD | [kqueue] |
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/// | FreeBSD | [kqueue] |
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/// | iOS | [kqueue] |
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/// | illumos | [epoll] |
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/// | Linux | [epoll] |
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/// | NetBSD | [kqueue] |
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/// | OpenBSD | [kqueue] |
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/// | Windows | [IOCP] |
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/// | macOS | [kqueue] |
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///
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/// On all supported platforms, socket operations are handled by using the
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/// system selector. Platform specific extensions (e.g. [`SourceFd`]) allow
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/// accessing other features provided by individual system selectors. For
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/// example, Linux's [`signalfd`] feature can be used by registering the FD with
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/// `Poll` via [`SourceFd`].
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///
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/// On all platforms except windows, a call to [`Poll::poll`] is mostly just a
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/// direct call to the system selector. However, [IOCP] uses a completion model
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/// instead of a readiness model. In this case, `Poll` must adapt the completion
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/// model Mio's API. While non-trivial, the bridge layer is still quite
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/// efficient. The most expensive part being calls to `read` and `write` require
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/// data to be copied into an intermediate buffer before it is passed to the
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/// kernel.
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///
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/// [epoll]: https://man7.org/linux/man-pages/man7/epoll.7.html
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/// [kqueue]: https://www.freebsd.org/cgi/man.cgi?query=kqueue&sektion=2
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/// [IOCP]: https://docs.microsoft.com/en-us/windows/win32/fileio/i-o-completion-ports
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/// [`signalfd`]: https://man7.org/linux/man-pages/man2/signalfd.2.html
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/// [`SourceFd`]: unix/struct.SourceFd.html
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/// [`Poll::poll`]: struct.Poll.html#method.poll
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pub struct Poll {
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registry: Registry,
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}
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/// Registers I/O resources.
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pub struct Registry {
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selector: sys::Selector,
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/// Whether this selector currently has an associated waker.
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#[cfg(all(debug_assertions, not(target_os = "wasi")))]
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has_waker: Arc<AtomicBool>,
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}
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impl Poll {
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cfg_os_poll! {
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/// Return a new `Poll` handle.
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///
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/// This function will make a syscall to the operating system to create
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/// the system selector. If this syscall fails, `Poll::new` will return
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/// with the error.
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///
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/// close-on-exec flag is set on the file descriptors used by the selector to prevent
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/// leaking it to executed processes. However, on some systems such as
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/// old Linux systems that don't support `epoll_create1` syscall it is done
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/// non-atomically, so a separate thread executing in parallel to this
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/// function may accidentally leak the file descriptor if it executes a
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/// new process before this function returns.
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///
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/// See [struct] level docs for more details.
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///
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/// [struct]: struct.Poll.html
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///
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/// # Examples
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///
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/// ```
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/// # use std::error::Error;
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/// # fn main() -> Result<(), Box<dyn Error>> {
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/// use mio::{Poll, Events};
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/// use std::time::Duration;
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///
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/// let mut poll = match Poll::new() {
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/// Ok(poll) => poll,
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/// Err(e) => panic!("failed to create Poll instance; err={:?}", e),
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/// };
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///
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/// // Create a structure to receive polled events
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/// let mut events = Events::with_capacity(1024);
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///
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/// // Wait for events, but none will be received because no
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/// // `event::Source`s have been registered with this `Poll` instance.
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/// poll.poll(&mut events, Some(Duration::from_millis(500)))?;
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/// assert!(events.is_empty());
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/// # Ok(())
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/// # }
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/// ```
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pub fn new() -> io::Result<Poll> {
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sys::Selector::new().map(|selector| Poll {
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registry: Registry {
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selector,
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#[cfg(all(debug_assertions, not(target_os = "wasi")))]
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has_waker: Arc::new(AtomicBool::new(false)),
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},
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})
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}
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}
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/// Create a separate `Registry` which can be used to register
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/// `event::Source`s.
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pub fn registry(&self) -> &Registry {
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&self.registry
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}
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/// Wait for readiness events
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///
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/// Blocks the current thread and waits for readiness events for any of the
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/// [`event::Source`]s that have been registered with this `Poll` instance.
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/// The function will block until either at least one readiness event has
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/// been received or `timeout` has elapsed. A `timeout` of `None` means that
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/// `poll` will block until a readiness event has been received.
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///
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/// The supplied `events` will be cleared and newly received readiness events
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/// will be pushed onto the end. At most `events.capacity()` events will be
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/// returned. If there are further pending readiness events, they will be
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/// returned on the next call to `poll`.
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///
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/// A single call to `poll` may result in multiple readiness events being
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/// returned for a single event source. For example, if a TCP socket becomes
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/// both readable and writable, it may be possible for a single readiness
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/// event to be returned with both [`readable`] and [`writable`] readiness
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/// **OR** two separate events may be returned, one with [`readable`] set
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/// and one with [`writable`] set.
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///
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/// Note that the `timeout` will be rounded up to the system clock
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/// granularity (usually 1ms), and kernel scheduling delays mean that
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/// the blocking interval may be overrun by a small amount.
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///
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/// See the [struct] level documentation for a higher level discussion of
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/// polling.
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///
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/// [`event::Source`]: ./event/trait.Source.html
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/// [`readable`]: struct.Interest.html#associatedconstant.READABLE
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/// [`writable`]: struct.Interest.html#associatedconstant.WRITABLE
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/// [struct]: struct.Poll.html
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/// [`iter`]: ./event/struct.Events.html#method.iter
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///
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/// # Notes
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///
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/// This returns any errors without attempting to retry, previous versions
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/// of Mio would automatically retry the poll call if it was interrupted
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/// (if `EINTR` was returned).
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///
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/// Currently if the `timeout` elapses without any readiness events
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/// triggering this will return `Ok(())`. However we're not guaranteeing
|
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/// this behaviour as this depends on the OS.
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///
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/// # Examples
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///
|
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/// A basic example -- establishing a `TcpStream` connection.
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///
|
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#[cfg_attr(all(feature = "os-poll", feature = "net"), doc = "```")]
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#[cfg_attr(not(all(feature = "os-poll", feature = "net")), doc = "```ignore")]
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/// # use std::error::Error;
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/// # fn main() -> Result<(), Box<dyn Error>> {
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/// use mio::{Events, Poll, Interest, Token};
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/// use mio::net::TcpStream;
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///
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/// use std::net::{TcpListener, SocketAddr};
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/// use std::thread;
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///
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/// // Bind a server socket to connect to.
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/// let addr: SocketAddr = "127.0.0.1:0".parse()?;
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/// let server = TcpListener::bind(addr)?;
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/// let addr = server.local_addr()?.clone();
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///
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/// // Spawn a thread to accept the socket
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/// thread::spawn(move || {
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/// let _ = server.accept();
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/// });
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///
|
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/// // Construct a new `Poll` handle as well as the `Events` we'll store into
|
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/// let mut poll = Poll::new()?;
|
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/// let mut events = Events::with_capacity(1024);
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///
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/// // Connect the stream
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/// let mut stream = TcpStream::connect(addr)?;
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///
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/// // Register the stream with `Poll`
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/// poll.registry().register(
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/// &mut stream,
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/// Token(0),
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/// Interest::READABLE | Interest::WRITABLE)?;
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///
|
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/// // Wait for the socket to become ready. This has to happens in a loop to
|
||||
/// // handle spurious wakeups.
|
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/// loop {
|
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/// poll.poll(&mut events, None)?;
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///
|
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/// for event in &events {
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/// if event.token() == Token(0) && event.is_writable() {
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/// // The socket connected (probably, it could still be a spurious
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/// // wakeup)
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/// return Ok(());
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/// }
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/// }
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||||
/// }
|
||||
/// # }
|
||||
/// ```
|
||||
///
|
||||
/// [struct]: #
|
||||
pub fn poll(&mut self, events: &mut Events, timeout: Option<Duration>) -> io::Result<()> {
|
||||
self.registry.selector.select(events.sys(), timeout)
|
||||
}
|
||||
}
|
||||
|
||||
#[cfg(all(
|
||||
unix,
|
||||
not(mio_unsupported_force_poll_poll),
|
||||
not(any(target_os = "solaris", target_os = "vita"))
|
||||
))]
|
||||
impl AsRawFd for Poll {
|
||||
fn as_raw_fd(&self) -> RawFd {
|
||||
self.registry.as_raw_fd()
|
||||
}
|
||||
}
|
||||
|
||||
impl fmt::Debug for Poll {
|
||||
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||||
fmt.debug_struct("Poll").finish()
|
||||
}
|
||||
}
|
||||
|
||||
impl Registry {
|
||||
/// Register an [`event::Source`] with the `Poll` instance.
|
||||
///
|
||||
/// Once registered, the `Poll` instance will monitor the event source for
|
||||
/// readiness state changes. When it notices a state change, it will return
|
||||
/// a readiness event for the handle the next time [`poll`] is called.
|
||||
///
|
||||
/// See [`Poll`] docs for a high level overview.
|
||||
///
|
||||
/// # Arguments
|
||||
///
|
||||
/// `source: &mut S: event::Source`: This is the source of events that the
|
||||
/// `Poll` instance should monitor for readiness state changes.
|
||||
///
|
||||
/// `token: Token`: The caller picks a token to associate with the socket.
|
||||
/// When [`poll`] returns an event for the handle, this token is included.
|
||||
/// This allows the caller to map the event to its source. The token
|
||||
/// associated with the `event::Source` can be changed at any time by
|
||||
/// calling [`reregister`].
|
||||
///
|
||||
/// See documentation on [`Token`] for an example showing how to pick
|
||||
/// [`Token`] values.
|
||||
///
|
||||
/// `interest: Interest`: Specifies which operations `Poll` should monitor
|
||||
/// for readiness. `Poll` will only return readiness events for operations
|
||||
/// specified by this argument.
|
||||
///
|
||||
/// If a socket is registered with readable interest and the socket becomes
|
||||
/// writable, no event will be returned from [`poll`].
|
||||
///
|
||||
/// The readiness interest for an `event::Source` can be changed at any time
|
||||
/// by calling [`reregister`].
|
||||
///
|
||||
/// # Notes
|
||||
///
|
||||
/// Callers must ensure that if a source being registered with a `Poll`
|
||||
/// instance was previously registered with that `Poll` instance, then a
|
||||
/// call to [`deregister`] has already occurred. Consecutive calls to
|
||||
/// `register` is unspecified behavior.
|
||||
///
|
||||
/// Unless otherwise specified, the caller should assume that once an event
|
||||
/// source is registered with a `Poll` instance, it is bound to that `Poll`
|
||||
/// instance for the lifetime of the event source. This remains true even
|
||||
/// if the event source is deregistered from the poll instance using
|
||||
/// [`deregister`].
|
||||
///
|
||||
/// [`event::Source`]: ./event/trait.Source.html
|
||||
/// [`poll`]: struct.Poll.html#method.poll
|
||||
/// [`reregister`]: struct.Registry.html#method.reregister
|
||||
/// [`deregister`]: struct.Registry.html#method.deregister
|
||||
/// [`Token`]: struct.Token.html
|
||||
///
|
||||
/// # Examples
|
||||
///
|
||||
#[cfg_attr(all(feature = "os-poll", feature = "net"), doc = "```")]
|
||||
#[cfg_attr(not(all(feature = "os-poll", feature = "net")), doc = "```ignore")]
|
||||
/// # use std::error::Error;
|
||||
/// # use std::net;
|
||||
/// # fn main() -> Result<(), Box<dyn Error>> {
|
||||
/// use mio::{Events, Poll, Interest, Token};
|
||||
/// use mio::net::TcpStream;
|
||||
/// use std::net::SocketAddr;
|
||||
/// use std::time::{Duration, Instant};
|
||||
///
|
||||
/// let mut poll = Poll::new()?;
|
||||
///
|
||||
/// let address: SocketAddr = "127.0.0.1:0".parse()?;
|
||||
/// let listener = net::TcpListener::bind(address)?;
|
||||
/// let mut socket = TcpStream::connect(listener.local_addr()?)?;
|
||||
///
|
||||
/// // Register the socket with `poll`
|
||||
/// poll.registry().register(
|
||||
/// &mut socket,
|
||||
/// Token(0),
|
||||
/// Interest::READABLE | Interest::WRITABLE)?;
|
||||
///
|
||||
/// let mut events = Events::with_capacity(1024);
|
||||
/// let start = Instant::now();
|
||||
/// let timeout = Duration::from_millis(500);
|
||||
///
|
||||
/// loop {
|
||||
/// let elapsed = start.elapsed();
|
||||
///
|
||||
/// if elapsed >= timeout {
|
||||
/// // Connection timed out
|
||||
/// return Ok(());
|
||||
/// }
|
||||
///
|
||||
/// let remaining = timeout - elapsed;
|
||||
/// poll.poll(&mut events, Some(remaining))?;
|
||||
///
|
||||
/// for event in &events {
|
||||
/// if event.token() == Token(0) {
|
||||
/// // Something (probably) happened on the socket.
|
||||
/// return Ok(());
|
||||
/// }
|
||||
/// }
|
||||
/// }
|
||||
/// # }
|
||||
/// ```
|
||||
pub fn register<S>(&self, source: &mut S, token: Token, interests: Interest) -> io::Result<()>
|
||||
where
|
||||
S: event::Source + ?Sized,
|
||||
{
|
||||
trace!(
|
||||
"registering event source with poller: token={:?}, interests={:?}",
|
||||
token,
|
||||
interests
|
||||
);
|
||||
source.register(self, token, interests)
|
||||
}
|
||||
|
||||
/// Re-register an [`event::Source`] with the `Poll` instance.
|
||||
///
|
||||
/// Re-registering an event source allows changing the details of the
|
||||
/// registration. Specifically, it allows updating the associated `token`
|
||||
/// and `interests` specified in previous `register` and `reregister` calls.
|
||||
///
|
||||
/// The `reregister` arguments fully override the previous values. In other
|
||||
/// words, if a socket is registered with [`readable`] interest and the call
|
||||
/// to `reregister` specifies [`writable`], then read interest is no longer
|
||||
/// requested for the handle.
|
||||
///
|
||||
/// The event source must have previously been registered with this instance
|
||||
/// of `Poll`, otherwise the behavior is unspecified.
|
||||
///
|
||||
/// See the [`register`] documentation for details about the function
|
||||
/// arguments and see the [`struct`] docs for a high level overview of
|
||||
/// polling.
|
||||
///
|
||||
/// # Examples
|
||||
///
|
||||
#[cfg_attr(all(feature = "os-poll", feature = "net"), doc = "```")]
|
||||
#[cfg_attr(not(all(feature = "os-poll", feature = "net")), doc = "```ignore")]
|
||||
/// # use std::error::Error;
|
||||
/// # use std::net;
|
||||
/// # fn main() -> Result<(), Box<dyn Error>> {
|
||||
/// use mio::{Poll, Interest, Token};
|
||||
/// use mio::net::TcpStream;
|
||||
/// use std::net::SocketAddr;
|
||||
///
|
||||
/// let poll = Poll::new()?;
|
||||
///
|
||||
/// let address: SocketAddr = "127.0.0.1:0".parse()?;
|
||||
/// let listener = net::TcpListener::bind(address)?;
|
||||
/// let mut socket = TcpStream::connect(listener.local_addr()?)?;
|
||||
///
|
||||
/// // Register the socket with `poll`, requesting readable
|
||||
/// poll.registry().register(
|
||||
/// &mut socket,
|
||||
/// Token(0),
|
||||
/// Interest::READABLE)?;
|
||||
///
|
||||
/// // Reregister the socket specifying write interest instead. Even though
|
||||
/// // the token is the same it must be specified.
|
||||
/// poll.registry().reregister(
|
||||
/// &mut socket,
|
||||
/// Token(0),
|
||||
/// Interest::WRITABLE)?;
|
||||
/// # Ok(())
|
||||
/// # }
|
||||
/// ```
|
||||
///
|
||||
/// [`event::Source`]: ./event/trait.Source.html
|
||||
/// [`struct`]: struct.Poll.html
|
||||
/// [`register`]: struct.Registry.html#method.register
|
||||
/// [`readable`]: ./event/struct.Event.html#is_readable
|
||||
/// [`writable`]: ./event/struct.Event.html#is_writable
|
||||
pub fn reregister<S>(&self, source: &mut S, token: Token, interests: Interest) -> io::Result<()>
|
||||
where
|
||||
S: event::Source + ?Sized,
|
||||
{
|
||||
trace!(
|
||||
"reregistering event source with poller: token={:?}, interests={:?}",
|
||||
token,
|
||||
interests
|
||||
);
|
||||
source.reregister(self, token, interests)
|
||||
}
|
||||
|
||||
/// Deregister an [`event::Source`] with the `Poll` instance.
|
||||
///
|
||||
/// When an event source is deregistered, the `Poll` instance will no longer
|
||||
/// monitor it for readiness state changes. Deregistering clears up any
|
||||
/// internal resources needed to track the handle. After an explicit call
|
||||
/// to this method completes, it is guaranteed that the token previously
|
||||
/// registered to this handle will not be returned by a future poll, so long
|
||||
/// as a happens-before relationship is established between this call and
|
||||
/// the poll.
|
||||
///
|
||||
/// The event source must have previously been registered with this instance
|
||||
/// of `Poll`, otherwise the behavior is unspecified.
|
||||
///
|
||||
/// A handle can be passed back to `register` after it has been
|
||||
/// deregistered; however, it must be passed back to the **same** `Poll`
|
||||
/// instance, otherwise the behavior is unspecified.
|
||||
///
|
||||
/// # Examples
|
||||
///
|
||||
#[cfg_attr(all(feature = "os-poll", feature = "net"), doc = "```")]
|
||||
#[cfg_attr(not(all(feature = "os-poll", feature = "net")), doc = "```ignore")]
|
||||
/// # use std::error::Error;
|
||||
/// # use std::net;
|
||||
/// # fn main() -> Result<(), Box<dyn Error>> {
|
||||
/// use mio::{Events, Poll, Interest, Token};
|
||||
/// use mio::net::TcpStream;
|
||||
/// use std::net::SocketAddr;
|
||||
/// use std::time::Duration;
|
||||
///
|
||||
/// let mut poll = Poll::new()?;
|
||||
///
|
||||
/// let address: SocketAddr = "127.0.0.1:0".parse()?;
|
||||
/// let listener = net::TcpListener::bind(address)?;
|
||||
/// let mut socket = TcpStream::connect(listener.local_addr()?)?;
|
||||
///
|
||||
/// // Register the socket with `poll`
|
||||
/// poll.registry().register(
|
||||
/// &mut socket,
|
||||
/// Token(0),
|
||||
/// Interest::READABLE)?;
|
||||
///
|
||||
/// poll.registry().deregister(&mut socket)?;
|
||||
///
|
||||
/// let mut events = Events::with_capacity(1024);
|
||||
///
|
||||
/// // Set a timeout because this poll should never receive any events.
|
||||
/// poll.poll(&mut events, Some(Duration::from_secs(1)))?;
|
||||
/// assert!(events.is_empty());
|
||||
/// # Ok(())
|
||||
/// # }
|
||||
/// ```
|
||||
pub fn deregister<S>(&self, source: &mut S) -> io::Result<()>
|
||||
where
|
||||
S: event::Source + ?Sized,
|
||||
{
|
||||
trace!("deregistering event source from poller");
|
||||
source.deregister(self)
|
||||
}
|
||||
|
||||
/// Creates a new independently owned `Registry`.
|
||||
///
|
||||
/// Event sources registered with this `Registry` will be registered with
|
||||
/// the original `Registry` and `Poll` instance.
|
||||
pub fn try_clone(&self) -> io::Result<Registry> {
|
||||
self.selector.try_clone().map(|selector| Registry {
|
||||
selector,
|
||||
#[cfg(all(debug_assertions, not(target_os = "wasi")))]
|
||||
has_waker: Arc::clone(&self.has_waker),
|
||||
})
|
||||
}
|
||||
|
||||
/// Internal check to ensure only a single `Waker` is active per [`Poll`]
|
||||
/// instance.
|
||||
#[cfg(all(debug_assertions, not(target_os = "wasi")))]
|
||||
pub(crate) fn register_waker(&self) {
|
||||
assert!(
|
||||
!self.has_waker.swap(true, Ordering::AcqRel),
|
||||
"Only a single `Waker` can be active per `Poll` instance"
|
||||
);
|
||||
}
|
||||
|
||||
/// Get access to the `sys::Selector`.
|
||||
#[cfg(any(not(target_os = "wasi"), feature = "net"))]
|
||||
pub(crate) fn selector(&self) -> &sys::Selector {
|
||||
&self.selector
|
||||
}
|
||||
}
|
||||
|
||||
impl fmt::Debug for Registry {
|
||||
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||||
fmt.debug_struct("Registry").finish()
|
||||
}
|
||||
}
|
||||
|
||||
#[cfg(all(
|
||||
unix,
|
||||
not(mio_unsupported_force_poll_poll),
|
||||
not(any(target_os = "solaris", target_os = "vita"))
|
||||
))]
|
||||
impl AsRawFd for Registry {
|
||||
fn as_raw_fd(&self) -> RawFd {
|
||||
self.selector.as_raw_fd()
|
||||
}
|
||||
}
|
||||
|
||||
cfg_os_poll! {
|
||||
#[cfg(all(
|
||||
unix,
|
||||
not(mio_unsupported_force_poll_poll),
|
||||
not(any(target_os = "solaris", target_os = "vita")),
|
||||
))]
|
||||
#[test]
|
||||
pub fn as_raw_fd() {
|
||||
let poll = Poll::new().unwrap();
|
||||
assert!(poll.as_raw_fd() > 0);
|
||||
}
|
||||
}
|
||||
Loading…
Add table
Add a link
Reference in a new issue