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use std::{ future::Future, marker::PhantomData, ops::{Deref, DerefMut}, pin::Pin, task::{Context, Poll}, time::Duration, }; use pin_project_lite::pin_project; pub use either::Either; pub use map::Map; pub use then::Then; pub use timeout::Timeout; use crate::actor::Actor; mod either; mod map; pub mod result; mod then; mod timeout; /// Trait for types which are a placeholder of a value that may become /// available at some later point in time. /// /// `ActorFuture` is very similar to a regular `Future`, only with subsequent combinator closures accepting the actor and its context, in addition to the result. /// /// `ActorFuture` allows for use cases where future processing requires access to the actor or its context. /// /// Here is an example of a handler on a single actor, deferring work to another actor, and /// then updating the initiating actor's state: /// /// ```no_run /// use actix::prelude::*; /// /// // The response type returned by the actor future /// type OriginalActorResponse = (); /// // The error type returned by the actor future /// type MessageError = (); /// // This is the needed result for the DeferredWork message /// // It's a result that combine both Response and Error from the future response. /// type DeferredWorkResult = Result<OriginalActorResponse, MessageError>; /// # /// # struct ActorState {} /// # /// # impl ActorState { /// # fn update_from(&mut self, _result: ()) {} /// # } /// # /// # struct OtherActor {} /// # /// # impl Actor for OtherActor { /// # type Context = Context<Self>; /// # } /// # /// # impl Handler<OtherMessage> for OtherActor { /// # type Result = (); /// # /// # fn handle(&mut self, _msg: OtherMessage, _ctx: &mut Context<Self>) -> Self::Result { /// # } /// # } /// # /// # struct OriginalActor{ /// # other_actor: Addr<OtherActor>, /// # inner_state: ActorState /// # } /// # /// # impl Actor for OriginalActor{ /// # type Context = Context<Self>; /// # } /// # /// # #[derive(Message)] /// # #[rtype(result = "Result<(), MessageError>")] /// # struct DeferredWork{} /// # /// # #[derive(Message)] /// # #[rtype(result = "()")] /// # struct OtherMessage{} /// /// impl Handler<DeferredWork> for OriginalActor { /// // Notice the `Response` is an `ActorFuture`-ized version of `Self::Message::Result`. /// type Result = ResponseActFuture<Self, Result<OriginalActorResponse, MessageError>>; /// /// fn handle(&mut self, _msg: DeferredWork, _ctx: &mut Context<Self>) -> Self::Result { /// // this creates a `Future` representing the `.send` and subsequent `Result` from /// // `other_actor` /// let send_to_other = self.other_actor /// .send(OtherMessage {}); /// /// // Wrap that `Future` so subsequent chained handlers can access /// // the `actor` (`self` in the synchronous code) as well as the context. /// let send_to_other = actix::fut::wrap_future::<_, Self>(send_to_other); /// /// // once the wrapped future resolves, update this actor's state /// let update_self = send_to_other.map(|result, actor, _ctx| { /// // Actor's state updated here /// match result { /// Ok(v) => { /// actor.inner_state.update_from(v); /// Ok(()) /// }, /// // Failed to send message to other_actor /// Err(_e) => Err(()), /// } /// }); /// /// // return the wrapped future /// Box::pin(update_self) /// } /// } /// /// ``` /// /// See also [into_actor](trait.WrapFuture.html#tymethod.into_actor), which provides future conversion using trait pub trait ActorFuture<A: Actor> { /// The type of value that this future will resolved with if it is /// successful. type Output; fn poll( self: Pin<&mut Self>, srv: &mut A, ctx: &mut A::Context, task: &mut Context<'_>, ) -> Poll<Self::Output>; } pub trait ActorFutureExt<A: Actor>: ActorFuture<A> { /// Map this future's result to a different type, returning a new future of /// the resulting type. fn map<Fn, U>(self, f: Fn) -> Map<Self, Fn> where Fn: FnOnce(Self::Output, &mut A, &mut A::Context) -> U, Self: Sized, { Map::new(self, f) } /// Chain on a computation for when a future finished, passing the result of /// the future to the provided closure `f`. fn then<Fn, Fut>(self, f: Fn) -> Then<Self, Fut, Fn> where Fn: FnOnce(Self::Output, &mut A, &mut A::Context) -> Fut, Fut: IntoActorFuture<A>, Self: Sized, { then::new(self, f) } /// Add timeout to futures chain. /// /// `Err(())` returned as a timeout error. fn timeout(self, timeout: Duration) -> Timeout<Self> where Self: Sized, { Timeout::new(self, timeout) } } impl<F, A> ActorFutureExt<A> for F where F: ActorFuture<A>, A: Actor, { } /// Type alias for a pinned box ActorFuture trait object. pub type LocalBoxActorFuture<A, I> = Pin<Box<dyn ActorFuture<A, Output = I>>>; /// Class of types which can be converted into an actor future. /// /// This trait is very similar to the `IntoIterator` trait and is intended to be /// used in a very similar fashion. pub trait IntoActorFuture<A: Actor> { /// The future that this type can be converted into. type Future: ActorFuture<A, Output = Self::Output>; /// The item that the future may resolve with. type Output; /// Consumes this object and produces a future. fn into_future(self) -> Self::Future; } impl<F, A> IntoActorFuture<A> for F where F: ActorFuture<A> + Sized, A: Actor, { type Future = F; type Output = F::Output; fn into_future(self) -> F { self } } impl<F, A> ActorFuture<A> for Box<F> where F: ActorFuture<A> + Unpin + ?Sized, A: Actor, { type Output = F::Output; fn poll( mut self: Pin<&mut Self>, srv: &mut A, ctx: &mut A::Context, task: &mut Context<'_>, ) -> Poll<Self::Output> { Pin::new(&mut **self.as_mut()).poll(srv, ctx, task) } } impl<P, A> ActorFuture<A> for Pin<P> where P: Unpin + DerefMut, <P as Deref>::Target: ActorFuture<A>, A: Actor, { type Output = <<P as Deref>::Target as ActorFuture<A>>::Output; fn poll( self: Pin<&mut Self>, srv: &mut A, ctx: &mut A::Context, task: &mut Context<'_>, ) -> Poll<Self::Output> { Pin::get_mut(self).as_mut().poll(srv, ctx, task) } } /// Helper trait that allows conversion of normal future into `ActorFuture` pub trait WrapFuture<A> where A: Actor, { /// The future that this type can be converted into. type Future: ActorFuture<A, Output = Self::Output>; /// The item that the future may resolve with. type Output; #[deprecated(since = "0.11.0", note = "Please use WrapFuture::into_actor")] #[doc(hidden)] fn actfuture(self) -> Self::Future; /// Convert normal future to a ActorFuture fn into_actor(self, a: &A) -> Self::Future; } impl<F: Future, A: Actor> WrapFuture<A> for F { type Future = FutureWrap<F, A>; type Output = F::Output; #[doc(hidden)] fn actfuture(self) -> Self::Future { wrap_future(self) } fn into_actor(self, _: &A) -> Self::Future { wrap_future(self) } } pin_project! { pub struct FutureWrap<F, A> where F: Future, A: Actor, { #[pin] fut: F, _act: PhantomData<A> } } /// Converts normal future into `ActorFuture`, allowing its processing to /// use the actor's state. /// /// See the documentation for [ActorFuture](trait.ActorFuture.html) for a practical example involving both /// `wrap_future` and `ActorFuture` pub fn wrap_future<F, A>(f: F) -> FutureWrap<F, A> where F: Future, A: Actor, { FutureWrap { fut: f, _act: PhantomData, } } impl<F, A> ActorFuture<A> for FutureWrap<F, A> where F: Future, A: Actor, { type Output = F::Output; fn poll( self: Pin<&mut Self>, _: &mut A, _: &mut A::Context, task: &mut Context<'_>, ) -> Poll<Self::Output> { self.project().fut.poll(task) } }