zio.stm.TPromise.scala Maven / Gradle / Ivy
/*
* Copyright 2019-2024 John A. De Goes and the ZIO Contributors
*
* 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 zio.stm
import zio.stacktracer.TracingImplicits.disableAutoTrace
import zio.Unsafe
final class TPromise[E, A] private (val ref: TRef[Option[Either[E, A]]]) extends AnyVal {
def await: STM[E, A] =
ref.get.collect { case Some(e) =>
STM.fromEither(e)
}.flatten
def done(v: Either[E, A]): USTM[Boolean] =
ref.get.flatMap {
case Some(_) => STM.succeedNow(false)
case None => ref.set(Some(v)) *> STM.succeedNow(true)
}
def fail(e: E): USTM[Boolean] =
done(Left(e))
def poll: USTM[Option[Either[E, A]]] =
ref.get
def succeed(a: A): USTM[Boolean] =
done(Right(a))
}
object TPromise {
def make[E, A]: USTM[TPromise[E, A]] =
ZSTM.succeed(unsafe.make()(Unsafe.unsafe))
object unsafe {
def make[E, A]()(implicit unsafe: Unsafe): TPromise[E, A] =
new TPromise(TRef.unsafeMake[Option[Either[E, A]]](None))
}
}