diff options
Diffstat (limited to 'simulator/opendc-utils/src/main')
| -rw-r--r-- | simulator/opendc-utils/src/main/kotlin/org/opendc/utils/TimerScheduler.kt | 240 |
1 files changed, 0 insertions, 240 deletions
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<T>(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<Timer>() - - /** - * A map that keeps track of the timers. - */ - private val timers = mutableMapOf<T, Timer>() - - /** - * The channel to communicate with the scheduling job. - */ - private val channel = Channel<Long?>(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<Timer> { - /** - * 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) - } -} |