[RFC] Change Service associated Request type to a type parameter
#1
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Signed-off-by: Eliza Weisman <eliza@buoyant.io>
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
| impl<D, I> WithPeakEwma<D, I> | ||
| where | ||
| D: Discover, | ||
| I: Instrument<Handle, D::Response>, |
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The bounds on this impl block had to be removed because the Discover trait was made generic, and the type parameter R for Discover's request type would be unbounded w/o PhantomData.
| S: Service, | ||
| I: Instrument<Handle, S::Response>, | ||
| { | ||
| impl<S, I> PeakEwma<S, I> { |
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The bounds on this impl block had to be removed because the R type parameter on Service would be unbounded without a PhantomData field on PeakEwma.
| pub struct ResponseFuture<T> | ||
| where T: Service, | ||
| pub struct ResponseFuture<T, R> | ||
| where T: Service<R>, |
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Additional generic type parameters were added to most of the types in tower-buffer for the request types of the wrapped Service, rather than removing the T: Service bounds. This was necessary since the associated types from the service type parameter are also used in struct definitions, so it was necessary to keep the T: Service bound
| struct ResponseInner<T, S> | ||
| where S: Service, | ||
| struct ResponseInner<T, S, R> | ||
| where S: Service<R>, |
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Again, we need to maintain the S: Service bound, since the struct definition uses S::Future, so the additional request type parameter was added.
| @@ -45,7 +44,7 @@ pub struct ResponseFuture<T> { | |||
| #[derive(Debug)] | |||
| enum State { | |||
| // The service has hit its limit | |||
| Limited(Sleep), | |||
| Limited(Delay), | |||
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Updated to use the new tokio-timer API as this crate no longer compiles otherwise. This is an unrelated change.
| @@ -3,16 +3,18 @@ extern crate tower_mock; | |||
| extern crate tower_rate_limit; | |||
| extern crate tower_service; | |||
| extern crate tokio_timer; | |||
| extern crate tokio; | |||
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It was necessary to update these tests to use tokio, as the new tokio_timer wouldn't work otherwise. This is an unrelated change, but was necessary for the rate-limit crate to compile.
| pub struct ResponseFuture<T> | ||
| where T: NewService | ||
| pub struct ResponseFuture<T, R> | ||
| where T: NewService<R> |
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Again, the T: NewService bound had to be maintained to use the T::Service associated type, so an additional type parameter was added.
| @@ -144,9 +142,28 @@ where T: NewService + fmt::Debug, | |||
| } | |||
| } | |||
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| // Manual impl of Debug for State because we should be able to | |||
| // format a state regardless of whether or not the request type | |||
| // is debug. | |||
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Since the State type became generic over requests, we had to add this impl of Debug as one could no longer be derived if R is not Debug, but R is not a member of the enum.
| inner: Option<T>, | ||
| _req: PhantomData<fn() -> R>, |
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A PhantomData was necessary here because the impl of Future for Ready needs a T: Service bound, and so we need the request type for that bound.
I think this could also be resolved by adding a T: Service<R> bound on the definition of Ready?
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Closing this as the change has already been made upstream. |
As described in tower-rs#99, this branch changes the
Service::Requestassociated type to a type parameter, and updates all thetowercrates to track that change.This PR is not necessarily intended to be merged, but is opened to allow the changes to be discussed and reviewed more easily.