pub trait Evented {
// Required methods
fn register(
&self,
poll: &Poll,
token: Token,
interest: Ready,
opts: PollOpt,
) -> Result<()>;
fn reregister(
&self,
poll: &Poll,
token: Token,
interest: Ready,
opts: PollOpt,
) -> Result<()>;
fn deregister(&self, poll: &Poll) -> Result<()>;
}Expand description
A value that may be registered with Poll
Values that implement Evented can be registered with Poll. Users of linux
should not use the Evented trait functions directly. Instead, the
equivalent functions on Poll should be used.
See Poll for more details.
§Implementing Evented
There are two types of Evented values.
-
System handles, which are backed by sockets or other system handles. These
Eventedhandles will be monitored by the system selector. In this case, an implementation ofEventeddelegates to a lower level handle. -
User handles, which are driven entirely in user space using
RegistrationandSetReadiness. In this case, the implementer takes responsibility for driving the readiness state changes.
§Examples
Implementing Evented on a struct containing a socket:
use futures_net::driver::sys::{Poll, Token};
use futures_net::driver::sys::event::{Ready, PollOpt};
use futures_net::driver::sys::event::Evented;
use futures_net::driver::sys::net::TcpStream;
use std::io;
pub struct MyEvented {
socket: TcpStream,
}
impl Evented for MyEvented {
fn register(&self, poll: &Poll, token: Token, interest: Ready, opts: PollOpt)
-> io::Result<()>
{
// Delegate the `register` call to `socket`
self.socket.register(poll, token, interest, opts)
}
fn reregister(&self, poll: &Poll, token: Token, interest: Ready, opts: PollOpt)
-> io::Result<()>
{
// Delegate the `reregister` call to `socket`
self.socket.reregister(poll, token, interest, opts)
}
fn deregister(&self, poll: &Poll) -> io::Result<()> {
// Delegate the `deregister` call to `socket`
self.socket.deregister(poll)
}
}Implement Evented using Registration and SetReadiness.
use futures_net::driver::sys::{Poll, Registration, Token};
use futures_net::driver::sys::event::{Events, Ready, PollOpt};
use futures_net::driver::sys::event::Evented;
use std::io;
use std::time::Instant;
use std::thread;
pub struct Deadline {
when: Instant,
registration: Registration,
}
impl Deadline {
pub fn new(when: Instant) -> Deadline {
let (registration, set_readiness) = Registration::new2();
thread::spawn(move || {
let now = Instant::now();
if now < when {
thread::sleep(when - now);
}
set_readiness.set_readiness(Ready::readable());
});
Deadline {
when: when,
registration: registration,
}
}
pub fn is_elapsed(&self) -> bool {
Instant::now() >= self.when
}
}
impl Evented for Deadline {
fn register(&self, poll: &Poll, token: Token, interest: Ready, opts: PollOpt)
-> io::Result<()>
{
self.registration.register(poll, token, interest, opts)
}
fn reregister(&self, poll: &Poll, token: Token, interest: Ready, opts: PollOpt)
-> io::Result<()>
{
self.registration.reregister(poll, token, interest, opts)
}
fn deregister(&self, poll: &Poll) -> io::Result<()> {
self.registration.deregister(poll)
}
}Required Methods§
Sourcefn register(
&self,
poll: &Poll,
token: Token,
interest: Ready,
opts: PollOpt,
) -> Result<()>
fn register( &self, poll: &Poll, token: Token, interest: Ready, opts: PollOpt, ) -> Result<()>
Register self with the given Poll instance.
This function should not be called directly. Use Poll::register
instead. Implementors should handle registration by either delegating
the call to another Evented type or creating a Registration.
Sourcefn reregister(
&self,
poll: &Poll,
token: Token,
interest: Ready,
opts: PollOpt,
) -> Result<()>
fn reregister( &self, poll: &Poll, token: Token, interest: Ready, opts: PollOpt, ) -> Result<()>
Re-register self with the given Poll instance.
This function should not be called directly. Use Poll::reregister
instead. Implementors should handle re-registration by either delegating
the call to another Evented type or calling
SetReadiness::set_readiness.
Sourcefn deregister(&self, poll: &Poll) -> Result<()>
fn deregister(&self, poll: &Poll) -> Result<()>
Deregister self from the given Poll instance
This function should not be called directly. Use Poll::deregister
instead. Implementors should handle deregistration by either delegating
the call to another Evented type or by dropping the Registration
associated with self.