Struct mio::Token
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pub struct Token(pub usize);
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 Copy for Token
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impl Clone for Token
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fn clone(&self) -> Token
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Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
1.0.0[src]
Performs copy-assignment from source
. Read more
impl Debug for Token
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fn fmt(&self, __arg_0: &mut Formatter) -> Result
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Formats the value using the given formatter. Read more
impl PartialEq for Token
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fn eq(&self, __arg_0: &Token) -> bool
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This method tests for self
and other
values to be equal, and is used by ==
. Read more
fn ne(&self, __arg_0: &Token) -> bool
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This method tests for !=
.
impl Eq for Token
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impl PartialOrd for Token
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fn partial_cmp(&self, __arg_0: &Token) -> Option<Ordering>
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This method returns an ordering between self
and other
values if one exists. Read more
fn lt(&self, __arg_0: &Token) -> bool
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This method tests less than (for self
and other
) and is used by the <
operator. Read more
fn le(&self, __arg_0: &Token) -> bool
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This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
fn gt(&self, __arg_0: &Token) -> bool
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This method tests greater than (for self
and other
) and is used by the >
operator. Read more
fn ge(&self, __arg_0: &Token) -> bool
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This method tests greater than or equal to (for self
and other
) and is used by the >=
operator. Read more
impl Ord for Token
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fn cmp(&self, __arg_0: &Token) -> Ordering
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This method returns an Ordering
between self
and other
. Read more
fn max(self, other: Self) -> Self
1.21.0[src]
Compares and returns the maximum of two values. Read more
fn min(self, other: Self) -> Self
1.21.0[src]
Compares and returns the minimum of two values. Read more
impl Hash for Token
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fn hash<__H: Hasher>(&self, __arg_0: &mut __H)
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Feeds this value into the given [Hasher
]. Read more
fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,
1.3.0[src]
H: Hasher,
Feeds a slice of this type into the given [Hasher
]. Read more