dev.tauri.choam.stm.TRefImpl.scala Maven / Gradle / Ivy
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/*
* SPDX-License-Identifier: Apache-2.0
* Copyright 2016-2024 Daniel Urban and contributors listed in NOTICE.txt
*
* 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 dev.tauri.choam
package stm
import java.lang.ref.WeakReference
import internal.mcas.MemoryLocation
private final class TRefImpl[F[_], A](
initial: A,
final override val id: Long,
) extends MemoryLocation[A] with TRef.UnsealedTRef[F, A] {
private[this] var contents: A =
initial
private[this] var version: Long =
internal.mcas.Version.Start
final override def unsafeGetV(): A =
contents
final override def unsafeGetP(): A =
contents
final override def unsafeSetV(nv: A): Unit =
contents = nv
final override def unsafeSetP(nv: A): Unit =
contents = nv
final override def unsafeCasV(ov: A, nv: A): Boolean = {
if (equ(contents, ov)) {
contents = nv
true
} else {
false
}
}
final override def unsafeCmpxchgV(ov: A, nv: A): A = {
val wit = contents
if (equ(wit, ov)) {
contents = nv
}
wit
}
final override def unsafeCmpxchgR(ov: A, nv: A): A =
this.unsafeCmpxchgV(ov, nv)
final override def unsafeGetVersionV(): Long =
version
final override def unsafeCmpxchgVersionV(ov: Long, nv: Long): Long = {
if (version == ov) {
version = nv
ov
} else {
version
}
}
final override def unsafeGetMarkerV(): WeakReference[AnyRef] =
impossible("TRefImpl#unsafeGetMarkerV called on JS")
final override def unsafeCasMarkerV(ov: WeakReference[AnyRef], nv: WeakReference[AnyRef]): Boolean =
impossible("TRefImpl#unsafeCasMarkerV called on JS")
final override def unsafeCmpxchgMarkerR(ov: WeakReference[AnyRef], nv: WeakReference[AnyRef]): WeakReference[AnyRef] =
impossible("TRefImpl#unsafeCmpxchgMarkerR called on JS")
final override def get: Txn[F, A] =
core.Rxn.loc.get(this).castF[F]
final override def set(a: A): Txn[F, Unit] =
core.Rxn.loc.upd[A, Unit, Unit](this) { (_, _) => (a, ()) }.castF[F]
final override def hashCode: Int = {
// `RefIdGen` generates IDs with
// Fibonacci hashing, so no need
// to hash them here even further.
// IDs are globally unique, so the
// default `equals` (based on object
// identity) is fine for us.
this.id.toInt
}
}