Trait Observer

pub trait Observer<Out: ?Sized> {
    // Provided methods
    fn on_first_poll(&mut self) { ... }
    fn on_poll(&mut self) { ... }
    fn on_poll_ready(&mut self, output: &Out) { ... }
    fn on_finish(&mut self, output: Option<&Out>) { ... }
    fn on_drop(&mut self) { ... }
}

Represents an observer, which reacts to different events happening to the future.

If any of the functions is used incorrectly, implementation’s behaviour could be undefined but must always be safe.

Provided Methods

fn on_first_poll(&mut self)

Called once before the first future’s poll.

fn on_poll(&mut self)

Called each time before the future is polled, but after on_first_poll.

fn on_poll_ready(&mut self, output: &Out)

Called once after the future returns Poll::Ready.

fn on_finish(&mut self, output: Option<&Out>)

Called once after on_poll_ready or before on_drop, depending on whether future was cancelled or not. It isn’t called if there was no call to on_first_poll.

fn on_drop(&mut self)

Called once before the future is dropped, therefore is never called twice and forbids calls to other trait’s functions.

Implementations on Foreign Types

impl<Out: ?Sized, O1> Observer<Out> for (O1,)

where O1: Observer<Out>,

fn on_first_poll(&mut self)

fn on_poll(&mut self)

fn on_poll_ready(&mut self, output: &Out)

fn on_finish(&mut self, output: Option<&Out>)

fn on_drop(&mut self)

impl<Out: ?Sized, O1, O2> Observer<Out> for (O1, O2)

where O1: Observer<Out>, O2: Observer<Out>,

fn on_first_poll(&mut self)

fn on_poll(&mut self)

fn on_poll_ready(&mut self, output: &Out)

fn on_finish(&mut self, output: Option<&Out>)

fn on_drop(&mut self)

impl<Out: ?Sized, O1, O2, O3> Observer<Out> for (O1, O2, O3)

where O1: Observer<Out>, O2: Observer<Out>, O3: Observer<Out>,

fn on_first_poll(&mut self)

fn on_poll(&mut self)

fn on_poll_ready(&mut self, output: &Out)

fn on_finish(&mut self, output: Option<&Out>)

fn on_drop(&mut self)

impl<Out: ?Sized, O1, O2, O3, O4> Observer<Out> for (O1, O2, O3, O4)

where O1: Observer<Out>, O2: Observer<Out>, O3: Observer<Out>, O4: Observer<Out>,

fn on_first_poll(&mut self)

fn on_poll(&mut self)

fn on_poll_ready(&mut self, output: &Out)

fn on_finish(&mut self, output: Option<&Out>)

fn on_drop(&mut self)

impl<Out: ?Sized, O1, O2, O3, O4, O5> Observer<Out> for (O1, O2, O3, O4, O5)

where O1: Observer<Out>, O2: Observer<Out>, O3: Observer<Out>, O4: Observer<Out>, O5: Observer<Out>,

fn on_first_poll(&mut self)

fn on_poll(&mut self)

fn on_poll_ready(&mut self, output: &Out)

fn on_finish(&mut self, output: Option<&Out>)

fn on_drop(&mut self)

impl<Out: ?Sized, O1, O2, O3, O4, O5, O6> Observer<Out> for (O1, O2, O3, O4, O5, O6)

where O1: Observer<Out>, O2: Observer<Out>, O3: Observer<Out>, O4: Observer<Out>, O5: Observer<Out>, O6: Observer<Out>,

fn on_first_poll(&mut self)

fn on_poll(&mut self)

fn on_poll_ready(&mut self, output: &Out)

fn on_finish(&mut self, output: Option<&Out>)

fn on_drop(&mut self)

impl<Out: ?Sized, O1, O2, O3, O4, O5, O6, O7> Observer<Out> for (O1, O2, O3, O4, O5, O6, O7)

where O1: Observer<Out>, O2: Observer<Out>, O3: Observer<Out>, O4: Observer<Out>, O5: Observer<Out>, O6: Observer<Out>, O7: Observer<Out>,

fn on_first_poll(&mut self)

fn on_poll(&mut self)

fn on_poll_ready(&mut self, output: &Out)

fn on_finish(&mut self, output: Option<&Out>)

fn on_drop(&mut self)

impl<Out: ?Sized, O1, O2, O3, O4, O5, O6, O7, O8> Observer<Out> for (O1, O2, O3, O4, O5, O6, O7, O8)

where O1: Observer<Out>, O2: Observer<Out>, O3: Observer<Out>, O4: Observer<Out>, O5: Observer<Out>, O6: Observer<Out>, O7: Observer<Out>, O8: Observer<Out>,

fn on_first_poll(&mut self)

fn on_poll(&mut self)

fn on_poll_ready(&mut self, output: &Out)

fn on_finish(&mut self, output: Option<&Out>)

fn on_drop(&mut self)

Implementors