| /* |
| * Copyright 2016-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license. |
| */ |
| |
| package kotlinx.coroutines |
| |
| import kotlinx.coroutines.internal.* |
| |
| /** |
| * Handler for [Job.invokeOnCompletion] and [CancellableContinuation.invokeOnCancellation]. |
| * |
| * Installed handler should not throw any exceptions. If it does, they will get caught, |
| * wrapped into [CompletionHandlerException], and rethrown, potentially causing crash of unrelated code. |
| * |
| * The meaning of `cause` that is passed to the handler: |
| * * Cause is `null` when the job has completed normally. |
| * * Cause is an instance of [CancellationException] when the job was cancelled _normally_. |
| * **It should not be treated as an error**. In particular, it should not be reported to error logs. |
| * * Otherwise, the job had _failed_. |
| * |
| * **Note**: This type is a part of internal machinery that supports parent-child hierarchies |
| * and allows for implementation of suspending functions that wait on the Job's state. |
| * This type should not be used in general application code. |
| * Implementations of `CompletionHandler` must be fast and _lock-free_. |
| */ |
| public typealias CompletionHandler = (cause: Throwable?) -> Unit |
| |
| // We want class that extends LockFreeLinkedListNode & CompletionHandler but we cannot do it on Kotlin/JS, |
| // so this expect class provides us with the corresponding abstraction in a platform-agnostic way. |
| internal expect abstract class CompletionHandlerBase() : LockFreeLinkedListNode { |
| abstract fun invoke(cause: Throwable?) |
| } |
| |
| internal expect val CompletionHandlerBase.asHandler: CompletionHandler |
| |
| // More compact version of CompletionHandlerBase for CancellableContinuation with same workaround for JS |
| internal expect abstract class CancelHandlerBase() { |
| abstract fun invoke(cause: Throwable?) |
| } |
| |
| internal expect val CancelHandlerBase.asHandler: CompletionHandler |
| |
| // :KLUDGE: We have to invoke a handler in platform-specific way via `invokeIt` extension, |
| // because we play type tricks on Kotlin/JS and handler is not necessarily a function there |
| internal expect fun CompletionHandler.invokeIt(cause: Throwable?) |
| |
| internal inline fun <reified T> CompletionHandler.isHandlerOf(): Boolean = this is T |