[−][src]Struct mio::Token
Associates readiness notifications with Evented
handles.
Token
is a wrapper around usize
and is used as an argument to
Poll::register
and Poll::reregister
.
See Poll
for more documentation on polling.
Example
Using Token
to track which socket generated the notification. In this
example, HashMap
is used, but usually something like slab
is better.
use mio::{Events, Ready, Poll, PollOpt, Token}; use mio::net::TcpListener; use std::thread; use std::io::{self, Read}; use std::collections::HashMap; // After this number of sockets is accepted, the server will shutdown. const MAX_SOCKETS: usize = 32; // Pick a token that will not be used by any other socket and use that one // for the listener. const LISTENER: Token = Token(1024); // Used to store the sockets. let mut sockets = HashMap::new(); // This is used to generate a unique token for a socket let mut next_socket_index = 0; // The `Poll` instance let poll = Poll::new()?; // Tcp listener let listener = TcpListener::bind(&"127.0.0.1:0".parse()?)?; // Register the listener poll.register(&listener, LISTENER, Ready::readable(), PollOpt::edge())?; // Spawn a thread that will connect a bunch of sockets then close them let addr = listener.local_addr()?; thread::spawn(move || { use std::net::TcpStream; // +1 here is to connect an extra socket to signal the socket to close for _ in 0..(MAX_SOCKETS+1) { // Connect then drop the socket let _ = TcpStream::connect(&addr).unwrap(); } }); // Event storage let mut events = Events::with_capacity(1024); // Read buffer, this will never actually get filled let mut buf = [0; 256]; // The main event loop loop { // Wait for events poll.poll(&mut events, None)?; for event in &events { match event.token() { LISTENER => { // Perform operations in a loop until `WouldBlock` is // encountered. loop { match listener.accept() { Ok((socket, _)) => { // Shutdown the server if next_socket_index == MAX_SOCKETS { return Ok(()); } // Get the token for the socket let token = Token(next_socket_index); next_socket_index += 1; // Register the new socket w/ poll poll.register(&socket, token, Ready::readable(), PollOpt::edge())?; // Store the socket sockets.insert(token, socket); } Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => { // Socket is not ready anymore, stop accepting break; } e => panic!("err={:?}", e), // Unexpected error } } } token => { // Always operate in a loop loop { match sockets.get_mut(&token).unwrap().read(&mut buf) { Ok(0) => { // Socket is closed, remove it from the map sockets.remove(&token); break; } // Data is not actually sent in this example Ok(_) => unreachable!(), Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => { // Socket is not ready anymore, stop reading break; } e => panic!("err={:?}", e), // Unexpected error } } } } } }
Trait Implementations
impl Eq for Token
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impl Clone for Token
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impl PartialOrd<Token> for Token
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fn partial_cmp(&self, other: &Token) -> Option<Ordering>
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fn lt(&self, other: &Token) -> bool
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fn le(&self, other: &Token) -> bool
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fn gt(&self, other: &Token) -> bool
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fn ge(&self, other: &Token) -> bool
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impl PartialEq<Token> for Token
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impl Ord for Token
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fn cmp(&self, other: &Token) -> Ordering
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fn max(self, other: Self) -> Self
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fn min(self, other: Self) -> Self
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fn clamp(self, min: Self, max: Self) -> Self
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impl From<usize> for Token
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impl From<Token> for usize
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impl Copy for Token
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impl Hash for Token
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fn hash<__H: Hasher>(&self, state: &mut __H)
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fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,
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H: Hasher,
impl Debug for Token
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Auto Trait Implementations
impl Send for Token
impl Unpin for Token
impl Sync for Token
impl UnwindSafe for Token
impl RefUnwindSafe for Token
Blanket Implementations
impl<T> ToOwned for T where
T: Clone,
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T: Clone,
type Owned = T
The resulting type after obtaining ownership.
fn to_owned(&self) -> T
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fn clone_into(&self, target: &mut T)
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> From<T> for T
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
ⓘImportant traits for &'_ mut Wfn borrow_mut(&mut self) -> &mut T
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ⓘImportant traits for &'_ mut W
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,