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/*
* Copyright 2016-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
*/
@file:Suppress("DEPRECATION_ERROR")
package kotlinx.coroutines
import kotlinx.coroutines.selects.*
import kotlin.coroutines.*
/**
* A non-cancelable job that is always [active][Job.isActive]. It is designed for [withContext] function
* to prevent cancellation of code blocks that need to be executed without cancellation.
*
* Use it like this:
* ```
* withContext(NonCancellable) {
* // this code will not be cancelled
* }
* ```
*
* **WARNING**: This object is not designed to be used with [launch], [async], and other coroutine builders.
* if you write `launch(NonCancellable) { ... }` then not only the newly launched job will not be cancelled
* when the parent is cancelled, the whole parent-child relation between parent and child is severed.
* The parent will not wait for the child's completion, nor will be cancelled when the child crashed.
*/
@Suppress("DeprecatedCallableAddReplaceWith")
public object NonCancellable : AbstractCoroutineContextElement(Job), Job {
private const val message = "NonCancellable can be used only as an argument for 'withContext', direct usages of its API are prohibited"
/**
* Always returns `true`.
* @suppress **This an internal API and should not be used from general code.**
*/
@Deprecated(level = DeprecationLevel.WARNING, message = message)
override val isActive: Boolean
get() = true
/**
* Always returns `false`.
* @suppress **This an internal API and should not be used from general code.**
*/
@Deprecated(level = DeprecationLevel.WARNING, message = message)
override val isCompleted: Boolean get() = false
/**
* Always returns `false`.
* @suppress **This an internal API and should not be used from general code.**
*/
@Deprecated(level = DeprecationLevel.WARNING, message = message)
override val isCancelled: Boolean get() = false
/**
* Always returns `false`.
* @suppress **This an internal API and should not be used from general code.**
*/
@Deprecated(level = DeprecationLevel.WARNING, message = message)
override fun start(): Boolean = false
/**
* Always throws [UnsupportedOperationException].
* @suppress **This an internal API and should not be used from general code.**
*/
@Deprecated(level = DeprecationLevel.WARNING, message = message)
override suspend fun join() {
throw UnsupportedOperationException("This job is always active")
}
/**
* Always throws [UnsupportedOperationException].
* @suppress **This an internal API and should not be used from general code.**
*/
@Deprecated(level = DeprecationLevel.WARNING, message = message)
override val onJoin: SelectClause0
get() = throw UnsupportedOperationException("This job is always active")
/**
* Always throws [IllegalStateException].
* @suppress **This an internal API and should not be used from general code.**
*/
@Deprecated(level = DeprecationLevel.WARNING, message = message)
override fun getCancellationException(): CancellationException = throw IllegalStateException("This job is always active")
/**
* @suppress **This an internal API and should not be used from general code.**
*/
@Deprecated(level = DeprecationLevel.WARNING, message = message)
override fun invokeOnCompletion(handler: CompletionHandler): DisposableHandle =
NonDisposableHandle
/**
* Always returns no-op handle.
* @suppress **This an internal API and should not be used from general code.**
*/
@Deprecated(level = DeprecationLevel.WARNING, message = message)
override fun invokeOnCompletion(onCancelling: Boolean, invokeImmediately: Boolean, handler: CompletionHandler): DisposableHandle =
NonDisposableHandle
/**
* Does nothing.
* @suppress **This an internal API and should not be used from general code.**
*/
@Deprecated(level = DeprecationLevel.WARNING, message = message)
override fun cancel(cause: CancellationException?) {}
/**
* Always returns `false`.
* @suppress This method has bad semantics when cause is not a [CancellationException]. Use [cancel].
*/
@Deprecated(level = DeprecationLevel.HIDDEN, message = "Since 1.2.0, binary compatibility with versions <= 1.1.x")
override fun cancel(cause: Throwable?): Boolean = false // never handles exceptions
/**
* Always returns [emptySequence].
* @suppress **This an internal API and should not be used from general code.**
*/
@Deprecated(level = DeprecationLevel.WARNING, message = message)
override val children: Sequence<Job>
get() = emptySequence()
/**
* Always returns [NonDisposableHandle] and does not do anything.
* @suppress **This an internal API and should not be used from general code.**
*/
@Deprecated(level = DeprecationLevel.WARNING, message = message)
override fun attachChild(child: ChildJob): ChildHandle = NonDisposableHandle
/** @suppress */
override fun toString(): String {
return "NonCancellable"
}
}
|
