From cd0b45627f0d8da8c8dc4edde223f3c36e9bcfbf Mon Sep 17 00:00:00 2001 From: Fabian Mastenbroek Date: Sun, 25 Apr 2021 16:01:14 +0200 Subject: build: Migrate to flat project structure This change updates the project structure to become flattened. Previously, the simulator, frontend and API each lived into their own directory. With this change, all modules of the project live in the top-level directory of the repository. This should improve discoverability of modules of the project. --- .../main/kotlin/org/opendc/utils/TimerScheduler.kt | 240 --------------------- 1 file changed, 240 deletions(-) delete mode 100644 simulator/opendc-utils/src/main/kotlin/org/opendc/utils/TimerScheduler.kt (limited to 'simulator/opendc-utils/src/main') diff --git a/simulator/opendc-utils/src/main/kotlin/org/opendc/utils/TimerScheduler.kt b/simulator/opendc-utils/src/main/kotlin/org/opendc/utils/TimerScheduler.kt deleted file mode 100644 index aa2f3367..00000000 --- a/simulator/opendc-utils/src/main/kotlin/org/opendc/utils/TimerScheduler.kt +++ /dev/null @@ -1,240 +0,0 @@ -/* - * Copyright (c) 2021 AtLarge Research - * - * Permission is hereby granted, free of charge, to any person obtaining a copy - * of this software and associated documentation files (the "Software"), to deal - * in the Software without restriction, including without limitation the rights - * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell - * copies of the Software, and to permit persons to whom the Software is - * furnished to do so, subject to the following conditions: - * - * The above copyright notice and this permission notice shall be included in all - * copies or substantial portions of the Software. - * - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR - * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE - * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER - * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, - * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE - * SOFTWARE. - */ - -package org.opendc.utils - -import kotlinx.coroutines.* -import kotlinx.coroutines.channels.Channel -import kotlinx.coroutines.channels.sendBlocking -import kotlinx.coroutines.selects.select -import java.time.Clock -import java.util.* -import kotlin.coroutines.CoroutineContext -import kotlin.math.max - -/** - * A TimerScheduler facilitates scheduled execution of future tasks. - * - * @param context The [CoroutineContext] to run the tasks with. - * @param clock The clock to keep track of the time. - */ -@OptIn(ExperimentalCoroutinesApi::class) -public class TimerScheduler(context: CoroutineContext, private val clock: Clock) : AutoCloseable { - /** - * The scope in which the scheduler runs. - */ - private val scope = CoroutineScope(context + Job()) - - /** - * A priority queue containing the tasks to be scheduled in the future. - */ - private val queue = PriorityQueue() - - /** - * A map that keeps track of the timers. - */ - private val timers = mutableMapOf() - - /** - * The channel to communicate with the scheduling job. - */ - private val channel = Channel(Channel.CONFLATED) - - /** - * A flag to indicate that the scheduler is active. - */ - private var isActive = true - - init { - scope.launch { - val timers = timers - val queue = queue - val clock = clock - val job = requireNotNull(coroutineContext[Job]) - val exceptionHandler = coroutineContext[CoroutineExceptionHandler] - var next: Long? = channel.receive() - - while (true) { - next = select { - channel.onReceive { it } - - val delay = next?.let { max(0L, it - clock.millis()) } ?: return@select - - onTimeout(delay) { - while (queue.isNotEmpty() && job.isActive) { - val timer = queue.peek() - val timestamp = clock.millis() - - assert(timer.timestamp >= timestamp) { "Found task in the past" } - - if (timer.timestamp > timestamp && !timer.isCancelled) { - // Schedule a task for the next event to occur. - return@onTimeout timer.timestamp - } - - queue.poll() - - if (!timer.isCancelled) { - timers.remove(timer.key) - try { - timer() - } catch (e: Throwable) { - exceptionHandler?.handleException(coroutineContext, e) - } - } - } - - null - } - } - } - } - } - - /** - * Stop the scheduler. - */ - override fun close() { - isActive = false - cancelAll() - scope.cancel() - } - - /** - * Cancel a timer with a given key. - * - * If canceling a timer that was already canceled, or key never was used to start - * a timer this operation will do nothing. - * - * @param key The key of the timer to cancel. - */ - public fun cancel(key: T) { - if (!isActive) { - return - } - - val timer = timers.remove(key) - - // Mark the timer as cancelled - timer?.isCancelled = true - - // Optimization: check whether we are the head of the queue - val queue = queue - val channel = channel - val peek = queue.peek() - if (peek == timer) { - queue.poll() - - if (queue.isNotEmpty()) { - channel.sendBlocking(peek.timestamp) - } else { - channel.sendBlocking(null) - } - } - } - - /** - * Cancel all timers. - */ - public fun cancelAll() { - queue.clear() - timers.clear() - } - - /** - * Check if a timer with a given key is active. - * - * @param key The key to check if active. - * @return `true` if the timer with the specified [key] is active, `false` otherwise. - */ - public fun isTimerActive(key: T): Boolean = key in timers - - /** - * Start a timer that will invoke the specified [block] after [delay]. - * - * Each timer has a key and if a new timer with same key is started the previous is cancelled. - * - * @param key The key of the timer to start. - * @param delay The delay before invoking the block. - * @param block The block to invoke. - */ - public fun startSingleTimer(key: T, delay: Long, block: () -> Unit) { - startSingleTimerTo(key, clock.millis() + delay, block) - } - - /** - * Start a timer that will invoke the specified [block] at [timestamp]. - * - * Each timer has a key and if a new timer with same key is started the previous is cancelled. - * - * @param key The key of the timer to start. - * @param timestamp The timestamp at which to invoke the block. - * @param block The block to invoke. - */ - public fun startSingleTimerTo(key: T, timestamp: Long, block: () -> Unit) { - val now = clock.millis() - val queue = queue - val channel = channel - - require(timestamp >= now) { "Timestamp must be in the future" } - check(isActive) { "Timer is stopped" } - - timers.compute(key) { _, old -> - if (old != null && old.timestamp == timestamp) { - // Fast-path: timer for the same timestamp already exists - old - } else { - // Slow-path: cancel old timer and replace it with new timer - val timer = Timer(key, timestamp, block) - - old?.isCancelled = true - queue.add(timer) - - // Check if we need to push the interruption forward - // Note that we check by timer reference - if (queue.peek() === timer) { - channel.offer(timer.timestamp) - } - - timer - } - } - } - - /** - * A task that is scheduled to run in the future. - */ - private inner class Timer(val key: T, val timestamp: Long, val block: () -> Unit) : Comparable { - /** - * A flag to indicate that the task has been cancelled. - */ - @JvmField - var isCancelled: Boolean = false - - /** - * Run the task. - */ - operator fun invoke(): Unit = block() - - override fun compareTo(other: Timer): Int = timestamp.compareTo(other.timestamp) - } -} -- cgit v1.2.3