pub struct Poller { /* private fields */ }
Expand description
Waits for I/O events.
Implementations
sourceimpl Poller
impl Poller
sourcepub fn add(&self, source: impl Source, interest: Event) -> Result<()>
pub fn add(&self, source: impl Source, interest: Event) -> Result<()>
Adds a file descriptor or socket to the poller.
A file descriptor or socket is considered readable or writable when a read or write operation on it would not block. This doesn’t mean the read or write operation will succeed, it only means the operation will return immediately.
If interest is set in both readability and writability, the two kinds of events might be delivered either separately or together.
For example, interest in Event { key: 7, readable: true, writable: true }
might result in
a single Event
of the same form, or in two separate Event
s:
Event { key: 7, readable: true, writable: false }
Event { key: 7, readable: false, writable: true }
Note that interest in I/O events needs to be re-enabled using
modify()
again after an event is delivered if we’re interested in
the next event of the same kind.
Don’t forget to delete()
the file descriptor or socket when it is
no longer used!
Errors
This method returns an error in the following situations:
- If
key
equalsusize::MAX
because that key is reserved for internal use. - If an error is returned by the syscall.
Examples
Set interest in all events:
use polling::{Event, Poller};
let source = std::net::TcpListener::bind("127.0.0.1:0")?;
source.set_nonblocking(true)?;
let key = 7;
let poller = Poller::new()?;
poller.add(&source, Event::all(key))?;
sourcepub fn modify(&self, source: impl Source, interest: Event) -> Result<()>
pub fn modify(&self, source: impl Source, interest: Event) -> Result<()>
Modifies the interest in a file descriptor or socket.
This method has the same behavior as add()
except it modifies the
interest of a previously added file descriptor or socket.
To use this method with a file descriptor or socket, you must first add it using
add()
.
Note that interest in I/O events needs to be re-enabled using
modify()
again after an event is delivered if we’re interested in
the next event of the same kind.
Errors
This method returns an error in the following situations:
- If
key
equalsusize::MAX
because that key is reserved for internal use. - If an error is returned by the syscall.
Examples
To enable interest in all events:
poller.modify(&source, Event::all(key))?;
To enable interest in readable events and disable interest in writable events:
poller.modify(&source, Event::readable(key))?;
To disable interest in readable events and enable interest in writable events:
poller.modify(&source, Event::writable(key))?;
To disable interest in all events:
poller.modify(&source, Event::none(key))?;
sourcepub fn delete(&self, source: impl Source) -> Result<()>
pub fn delete(&self, source: impl Source) -> Result<()>
Removes a file descriptor or socket from the poller.
Unlike add()
, this method only removes the file descriptor or
socket from the poller without putting it back into blocking mode.
Examples
use polling::{Event, Poller};
use std::net::TcpListener;
let socket = TcpListener::bind("127.0.0.1:0")?;
socket.set_nonblocking(true)?;
let key = 7;
let poller = Poller::new()?;
poller.add(&socket, Event::all(key))?;
poller.delete(&socket)?;
sourcepub fn wait(
&self,
events: &mut Vec<Event>,
timeout: Option<Duration>
) -> Result<usize>
pub fn wait(
&self,
events: &mut Vec<Event>,
timeout: Option<Duration>
) -> Result<usize>
Waits for at least one I/O event and returns the number of new events.
New events will be appended to events
. If necessary, make sure to clear the Vec
before calling wait()
!
This method will return with no new events if a notification is delivered by the
notify()
method, or the timeout is reached. Sometimes it may even return with no events
spuriously.
Only one thread can wait on I/O. If another thread is already in wait()
, concurrent
calls to this method will return immediately with no new events.
If the operating system is ready to deliver a large number of events at once, this method may decide to deliver them in smaller batches.
Examples
use polling::{Event, Poller};
use std::net::TcpListener;
use std::time::Duration;
let socket = TcpListener::bind("127.0.0.1:0")?;
socket.set_nonblocking(true)?;
let key = 7;
let poller = Poller::new()?;
poller.add(&socket, Event::all(key))?;
let mut events = Vec::new();
let n = poller.wait(&mut events, Some(Duration::from_secs(1)))?;
sourcepub fn notify(&self) -> Result<()>
pub fn notify(&self) -> Result<()>
Wakes up the current or the following invocation of wait()
.
If no thread is calling wait()
right now, this method will cause the following call
to wake up immediately.
Examples
use polling::Poller;
let poller = Poller::new()?;
// Notify the poller.
poller.notify()?;
let mut events = Vec::new();
poller.wait(&mut events, None)?; // wakes up immediately
assert!(events.is_empty());
Trait Implementations
Auto Trait Implementations
impl RefUnwindSafe for Poller
impl Send for Poller
impl Sync for Poller
impl Unpin for Poller
impl UnwindSafe for Poller
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more