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AsyncPlatform.scala
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AsyncPlatform.scala
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/*
* Copyright 2020-2022 Typelevel
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package cats.effect.kernel
import java.util.concurrent.{CompletableFuture, CompletionException, CompletionStage}
private[kernel] trait AsyncPlatform[F[_]] extends Serializable { this: Async[F] =>
def fromCompletionStage[A](completionStage: F[CompletionStage[A]]): F[A] =
fromCompletableFuture(flatMap(completionStage) { cs => delay(cs.toCompletableFuture()) })
/**
* Suspend a `java.util.concurrent.CompletableFuture` into the `F[_]` context.
*
* @param fut
* The `java.util.concurrent.CompletableFuture` to suspend in `F[_]`
*/
def fromCompletableFuture[A](fut: F[CompletableFuture[A]]): F[A] =
async[A] { cb =>
flatMap(fut) { cf =>
delay {
cf.handle[Unit] {
case (a, null) => cb(Right(a))
case (_, t) =>
cb(Left(t match {
case e: CompletionException if e.getCause ne null => e.getCause
case _ => t
}))
}
Some(
ifM(delay(cf.cancel(false)))(
unit,
async_[Unit] { cb =>
cf.handle[Unit]((_, _) => cb(Right(())))
()
}
))
}
}
}
}