| /* |
| * Copyright 2016-2017 JetBrains s.r.o. |
| * |
| * 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 kotlinx.coroutines.experimental |
| |
| import kotlinx.coroutines.experimental.selects.SelectBuilder |
| import kotlinx.coroutines.experimental.selects.select |
| import java.util.concurrent.Future |
| import java.util.concurrent.TimeUnit |
| import kotlin.coroutines.experimental.ContinuationInterceptor |
| |
| /** |
| * This dispatcher _feature_ is implemented by [CoroutineDispatcher] implementations that natively support |
| * scheduled execution of tasks. |
| * |
| * Implementation of this interface affects operation of |
| * [delay][kotlinx.coroutines.experimental.delay] and [withTimeout] functions. |
| */ |
| public interface Delay { |
| /** |
| * Delays coroutine for a given time without blocking a thread and resumes it after a specified time. |
| * This suspending function is cancellable. |
| * If the [Job] of the current coroutine is completed while this suspending function is suspended, this function |
| * immediately resumes with [CancellationException]. |
| */ |
| suspend fun delay(time: Long, unit: TimeUnit = TimeUnit.MILLISECONDS) { |
| require(time >= 0) { "Delay time $time cannot be negative" } |
| if (time <= 0) return // don't delay |
| return suspendCancellableCoroutine { scheduleResumeAfterDelay(time, unit, it) } |
| } |
| |
| /** |
| * Schedules resume of a specified [continuation] after a specified delay [time]. |
| * |
| * Continuation **must be scheduled** to resume even if it is already cancelled, because a cancellation is just |
| * an exception that the coroutine that used `delay` might wanted to catch and process. It might |
| * need to close some resources in its `finally` blocks, for example. |
| * |
| * This implementation is supposed to use dispatcher's native ability for scheduled execution in its thread(s). |
| * In order to avoid an extra delay of execution, the following code shall be used to resume this |
| * [continuation] when the code is already executing in the appropriate thread: |
| * |
| * ```kotlin |
| * with(continuation) { resumeUndispatched(Unit) } |
| * ``` |
| */ |
| fun scheduleResumeAfterDelay(time: Long, unit: TimeUnit, continuation: CancellableContinuation<Unit>) |
| |
| /** |
| * Schedules invocation of a specified [block] after a specified delay [time]. |
| * The resulting [DisposableHandle] can be used to [dispose][DisposableHandle.dispose] of this invocation |
| * request if it is not needed anymore. |
| * |
| * This implementation uses a built-in single-threaded scheduled executor service. |
| */ |
| fun invokeOnTimeout(time: Long, unit: TimeUnit, block: Runnable): DisposableHandle = |
| DisposableFutureHandle(scheduledExecutor.schedule(block, time, unit)) |
| } |
| |
| /** |
| * Delays coroutine for a given time without blocking a thread and resumes it after a specified time. |
| * This suspending function is cancellable. |
| * If the [Job] of the current coroutine is completed while this suspending function is suspended, this function |
| * immediately resumes with [CancellationException]. |
| * |
| * Note, that delay can be used in [select] invocation with [onTimeout][SelectBuilder.onTimeout] clause. |
| * |
| * This function delegates to [Delay.scheduleResumeAfterDelay] if the context [CoroutineDispatcher] |
| * implements [Delay] interface, otherwise it resumes using a built-in single-threaded scheduled executor service. |
| */ |
| suspend fun delay(time: Long, unit: TimeUnit = TimeUnit.MILLISECONDS) { |
| require(time >= 0) { "Delay time $time cannot be negative" } |
| if (time <= 0) return // don't delay |
| return suspendCancellableCoroutine sc@ { cont: CancellableContinuation<Unit> -> |
| val delay = cont.context[ContinuationInterceptor] as? Delay |
| if (delay != null) |
| delay.scheduleResumeAfterDelay(time, unit, cont) else |
| cont.cancelFutureOnCompletion(scheduledExecutor.schedule(ResumeRunnable(cont), time, unit)) |
| } |
| } |
| |
| /** |
| * An implementation of [DisposableHandle] that cancels the specified future on dispose. |
| */ |
| public class DisposableFutureHandle(private val future: Future<*>) : DisposableHandle { |
| override fun dispose() { |
| future.cancel(false) |
| } |
| override fun toString(): String = "DisposableFutureHandle[$future]" |
| } |