Moved the checkForTimeAdjustment() method in the generic time source behind the WaitOne() call because that's the most likely point for a date/time adjustment will have occurred at; WindowsTimeSource now exists on the XBox 360 as well, but will throw in its constructor and report Available as false (this simplifies things in other places); Scheduler class is fully working and 100% testable with simulated time (instead of waiting for scheduled notifications to be delivered in real time, which would make testing slow); added unit tests for Scheduler class and reached 100% coverage

git-svn-id: file:///srv/devel/repo-conversion/nusu@145 d2e56fa2-650e-0410-a79f-9358c0239efd
This commit is contained in:
Markus Ewald 2009-06-09 19:28:11 +00:00
parent 4b9002b520
commit a6f7749121
4 changed files with 525 additions and 43 deletions

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@ -87,12 +87,18 @@ namespace Nuclex.Support.Scheduling {
/// True if the WaitHandle was signalled, false if the timeout was reached /// True if the WaitHandle was signalled, false if the timeout was reached
/// </returns> /// </returns>
public virtual bool WaitOne(AutoResetEvent waitHandle, long ticks) { public virtual bool WaitOne(AutoResetEvent waitHandle, long ticks) {
checkForTimeAdjustment();
// Force a timeout at least each second so the caller can check the system time // Force a timeout at least each second so the caller can check the system time
// since we're not able to provide the DateTimeAdjusted notification // since we're not able to provide the DateTimeAdjusted notification
int milliseconds = (int)(ticks / TicksPerMillisecond); int milliseconds = (int)(ticks / TicksPerMillisecond);
return waitHandle.WaitOne(Math.Min(1000, milliseconds), false); bool signalled = waitHandle.WaitOne(Math.Min(1000, milliseconds), false);
// See whether the system date/time have been adjusted while we were asleep.
checkForTimeAdjustment();
// Now tell the caller whether his even was signalled
return signalled;
} }
/// <summary>Current system time in UTC format</summary> /// <summary>Current system time in UTC format</summary>

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@ -29,14 +29,175 @@ using Microsoft.Win32;
using NUnit.Framework; using NUnit.Framework;
#if false
namespace Nuclex.Support.Scheduling { namespace Nuclex.Support.Scheduling {
/// <summary>Unit Test for the scheduler</summary> /// <summary>Unit Test for the scheduler</summary>
[TestFixture] [TestFixture]
public class SchedulerTest { public class SchedulerTest {
#region class MockTimeSource
/// <summary>Mocked time source</summary>
private class MockTimeSource : ITimeSource {
/// <summary>Called when the system date/time are adjusted</summary>
public event EventHandler DateTimeAdjusted;
/// <summary>Initializes a new mocked time source</summary>
/// <param name="utcStartTime">Start time in UTC format</param>
public MockTimeSource(DateTime utcStartTime) {
this.currentTime = utcStartTime;
}
/// <summary>Waits for an AutoResetEvent to become signalled</summary>
/// <param name="waitHandle">WaitHandle the method will wait for</param>
/// <param name="ticks">Number of ticks to wait</param>
/// <returns>
/// True if the WaitHandle was signalled, false if the timeout was reached
/// or the time source thinks its time to recheck the system date/time.
/// </returns>
public bool WaitOne(AutoResetEvent waitHandle, long ticks) {
long currentTicks;
long eventDueTicks;
lock(this) {
this.autoResetEvent = waitHandle;
this.eventDueTicks += ticks;
currentTicks = this.currentTicks;
eventDueTicks = this.eventDueTicks;
}
// If we need to wait, use the wait handle. We do not use the wait handle's
// return value (or even its timeout) because we might trigger it ourselves
// to simulate the passing of time.
if(eventDueTicks > 0) {
this.autoResetEvent = waitHandle;
waitHandle.WaitOne();
this.autoResetEvent = null;
}
// Do not use the cached values here -- we might have used the WaitHandle and
// the simulation time could have been advanced while we were waiting.
lock(this) {
return (this.eventDueTicks > 0); // True = signalled, false = timed out
}
}
/// <summary>Current system time in UTC format</summary>
public DateTime CurrentUtcTime {
get { lock(this) { return this.currentTime; } }
}
/// <summary>How long the time source has been running</summary>
public long Ticks {
get {
lock(this) {
this.eventDueTicks = 0;
return this.currentTicks;
}
}
}
/// <summary>Advances the time of the time source</summary>
/// <param name="timeSpan">
/// Time span by which to advance the time source's time
/// </param>
public void AdvanceTime(TimeSpan timeSpan) {
lock(this) {
this.currentTicks += timeSpan.Ticks;
this.currentTime += timeSpan;
// Problem: The Scheduler has just calculated the remaining ticks until
// notification occurs. Next, another thread advances simulation time
// and then the scheduler calls this. It will wait, even though
// the simultion time has progressed.
// To compensate this, we track the remaining time until the event is due
// and allow for a negative time budget if AdvanceTime() is called after
// the scheduler has just queried the current tick count.
this.eventDueTicks -= timeSpan.Ticks;
if(this.eventDueTicks <= 0) {
AutoResetEvent copy = this.autoResetEvent;
if(copy != null) {
copy.Set();
}
}
}
}
/// <summary>Manually triggers the date time adjusted event</summary>
/// <param name="newUtcTime">New simulation time to jump to</param>
public void AdjustTime(DateTime newUtcTime) {
lock(this) {
this.currentTime = newUtcTime;
}
EventHandler copy = DateTimeAdjusted;
if(copy != null) {
copy(this, EventArgs.Empty);
}
}
/// <summary>Auto reset event the time source is currently waiting on</summary>
private volatile AutoResetEvent autoResetEvent;
/// <summary>Ticks at which the auto reset event will be due</summary>
private long eventDueTicks;
/// <summary>Current time source tick counter</summary>
private long currentTicks;
/// <summary>Current system time and date</summary>
private DateTime currentTime;
}
#endregion // class MockTimeSource
#region class TestSubscriber
/// <summary>Subscriber used to test the scheduler notifications</summary>
private class TestSubscriber : IDisposable {
/// <summary>Initializes a new test subscriber</summary>
public TestSubscriber() {
this.waitHandle = new AutoResetEvent(false);
}
/// <summary>Immediately releases all resources owned by the instance</summary>
public void Dispose() {
if(this.waitHandle != null) {
this.waitHandle.Close();
this.waitHandle = null;
}
}
/// <summary>Callback method that can be subscribed to the scheduler</summary>
/// <param name="state">Not used</param>
public void Callback(object state) {
Interlocked.Increment(ref this.callbackCount);
this.waitHandle.Set();
}
/// <summary>Blocks ther caller until the callback is invoked</summary>
/// <param name="milliseconds">
/// Maximum number of milliseconds to wait for the callback
/// </param>
/// <returns>True if the callback was invoked, false if the call timed out</returns>
public bool WaitForCallback(int milliseconds) {
return this.waitHandle.WaitOne(milliseconds);
}
/// <summary>Number of times the callback has been invoked</summary>
public int CallbackCount {
get { return Thread.VolatileRead(ref this.callbackCount); }
}
/// <summary>Callback invocation count</summary>
private int callbackCount;
/// <summary>WaitHandle used to wait for the callback</summary>
private AutoResetEvent waitHandle;
}
#endregion // class TestSubscriber
/// <summary> /// <summary>
/// Test whether the Scheduler can explicitely create a windows time source /// Test whether the Scheduler can explicitely create a windows time source
/// </summary> /// </summary>
@ -96,10 +257,200 @@ namespace Nuclex.Support.Scheduling {
using(Scheduler scheduler = new Scheduler()) { } using(Scheduler scheduler = new Scheduler()) { }
} }
/// <summary>
/// Verifies that the default constructor of the scheduler is working
/// </summary>
[Test]
public void TestThrowOnNotifyAtWithUnspecifiedDateTimeKind() {
using(TestSubscriber subscriber = new TestSubscriber()) {
using(Scheduler scheduler = new Scheduler()) {
Assert.Throws<ArgumentException>(
delegate() {
scheduler.NotifyAt(new DateTime(2000, 1, 1), subscriber.Callback);
}
);
}
}
}
/// <summary>
/// Tests whether the NotifyAt() method invokes the callback at the right time
/// </summary>
[Test]
public void TestNotifyAt() {
MockTimeSource mockTimeSource = new MockTimeSource(new DateTime(2010, 1, 1));
using(TestSubscriber subscriber = new TestSubscriber()) {
using(Scheduler scheduler = new Scheduler(mockTimeSource)) {
scheduler.NotifyAt(makeUtc(new DateTime(2010, 1, 2)), subscriber.Callback);
mockTimeSource.AdvanceTime(TimeSpan.FromDays(1));
Assert.IsTrue(subscriber.WaitForCallback(1000));
}
}
}
/// <summary>
/// Verifies that a notification at an absolute time is processed correctly
/// if a time synchronization occurs during the wait.
/// </summary>
[Test]
public void TestNotifyAtWithDateTimeAdjustment() {
MockTimeSource mockTimeSource = new MockTimeSource(new DateTime(2010, 1, 1));
using(TestSubscriber subscriber = new TestSubscriber()) {
using(Scheduler scheduler = new Scheduler(mockTimeSource)) {
scheduler.NotifyAt(makeUtc(new DateTime(2010, 1, 2)), subscriber.Callback);
// Let 12 hours pass, after that, we simulate a time synchronization
// that puts the system 12 hours ahead of the original time.
mockTimeSource.AdvanceTime(TimeSpan.FromHours(12));
mockTimeSource.AdjustTime(new DateTime(2010, 1, 2));
Assert.IsTrue(subscriber.WaitForCallback(1000));
}
}
}
/// <summary>Tests whether the scheduler's Cancel() method is working</summary>
[Test]
public void TestCancelNotification() {
MockTimeSource mockTimeSource = new MockTimeSource(new DateTime(2010, 1, 1));
using(TestSubscriber subscriber1 = new TestSubscriber()) {
using(TestSubscriber subscriber2 = new TestSubscriber()) {
using(Scheduler scheduler = new Scheduler(mockTimeSource)) {
object handle = scheduler.NotifyIn(
TimeSpan.FromHours(24), subscriber1.Callback
);
scheduler.NotifyIn(TimeSpan.FromHours(36), subscriber2.Callback);
mockTimeSource.AdvanceTime(TimeSpan.FromHours(12));
scheduler.Cancel(handle);
mockTimeSource.AdvanceTime(TimeSpan.FromHours(24));
// Wait for the second subscriber to be notified. This is still a race
// condition (there's no guarantee the thread pool will run tasks in
// the order they were added), but it's the best we can do without
// relying on an ugly Thread.Sleep() in this test.
Assert.IsTrue(subscriber2.WaitForCallback(1000));
Assert.AreEqual(0, subscriber1.CallbackCount);
}
}
}
}
/// <summary>
/// Tests the scheduler with two notifications that are scheduled in inverse
/// order of their due time.
/// </summary>
[Test]
public void TestInverseOrderNotification() {
MockTimeSource mockTimeSource = new MockTimeSource(new DateTime(2010, 1, 1));
using(TestSubscriber subscriber1 = new TestSubscriber()) {
using(TestSubscriber subscriber2 = new TestSubscriber()) {
using(Scheduler scheduler = new Scheduler(mockTimeSource)) {
scheduler.NotifyIn(TimeSpan.FromHours(24), subscriber1.Callback);
scheduler.NotifyIn(TimeSpan.FromHours(12), subscriber2.Callback);
mockTimeSource.AdvanceTime(TimeSpan.FromHours(18));
Assert.IsTrue(subscriber2.WaitForCallback(1000));
Assert.AreEqual(0, subscriber1.CallbackCount);
mockTimeSource.AdvanceTime(TimeSpan.FromHours(18));
Assert.IsTrue(subscriber1.WaitForCallback(1000));
}
}
}
}
/// <summary>
/// Tests the scheduler with two notifications that are scheduled to
/// occur at the exact same time
/// </summary>
[Test]
public void TestTwoNotificationsAtSameTime() {
MockTimeSource mockTimeSource = new MockTimeSource(new DateTime(2010, 1, 1));
using(TestSubscriber subscriber1 = new TestSubscriber()) {
using(TestSubscriber subscriber2 = new TestSubscriber()) {
using(Scheduler scheduler = new Scheduler(mockTimeSource)) {
scheduler.NotifyIn(60000, subscriber1.Callback);
scheduler.NotifyIn(60000, subscriber2.Callback);
mockTimeSource.AdvanceTime(TimeSpan.FromMilliseconds(60000));
Assert.IsTrue(subscriber1.WaitForCallback(1000));
Assert.IsTrue(subscriber2.WaitForCallback(1000));
}
}
}
}
/// <summary>
/// Verifies that the scheduler's NotifyEach() method is working correctly
/// </summary>
[Test]
public void TestNotifyEachWithMilliseconds() {
MockTimeSource mockTimeSource = new MockTimeSource(new DateTime(2010, 1, 1));
using(TestSubscriber subscriber = new TestSubscriber()) {
using(Scheduler scheduler = new Scheduler(mockTimeSource)) {
scheduler.NotifyEach(1000, 1000, subscriber.Callback);
mockTimeSource.AdvanceTime(TimeSpan.FromMilliseconds(4000));
// Wait for 4 invocations of the callback. We might not catch each trigger
// of the AutoResetEvent, but we know that it will be 4 at most.
for(int invocation = 0; invocation < 4; ++invocation) {
Assert.IsTrue(subscriber.WaitForCallback(1000));
if(subscriber.CallbackCount == 4) {
break;
}
}
}
}
}
/// <summary>
/// Verifies that the scheduler's NotifyEach() method is working correctly
/// </summary>
[Test]
public void TestNotifyEachWithTimespan() {
MockTimeSource mockTimeSource = new MockTimeSource(new DateTime(2010, 1, 1));
using(TestSubscriber subscriber = new TestSubscriber()) {
using(Scheduler scheduler = new Scheduler(mockTimeSource)) {
scheduler.NotifyEach(
TimeSpan.FromHours(12), TimeSpan.FromHours(1), subscriber.Callback
);
mockTimeSource.AdvanceTime(TimeSpan.FromHours(14));
// Wait for 3 invocations of the callback. We might not catch each trigger
// of the AutoResetEvent, but we know that it will be 3 at most.
for(int invocation = 0; invocation < 3; ++invocation) {
Assert.IsTrue(subscriber.WaitForCallback(1000));
if(subscriber.CallbackCount == 3) {
break;
}
}
}
}
}
/// <summary>Returns the provided date/time value as a utc time value</summary>
/// <param name="dateTime">Date/time value that will be returned as UTC</param>
/// <returns>The provided date/time value as UTC</returns>
/// <remarks>
/// This doesn't convert the time, it just returns the exact same date and time
/// but tags it as UTC by setting the DateTimeKind to UTC.
/// </remarks>
private static DateTime makeUtc(DateTime dateTime) {
return new DateTime(dateTime.Ticks, DateTimeKind.Utc);
}
} }
} // namespace Nuclex.Support.Scheduling } // namespace Nuclex.Support.Scheduling
#endif
#endif // UNITTEST #endif // UNITTEST

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@ -25,8 +25,6 @@ using System.Diagnostics;
using Nuclex.Support.Collections; using Nuclex.Support.Collections;
#if false
namespace Nuclex.Support.Scheduling { namespace Nuclex.Support.Scheduling {
/// <summary>Schedules actions for execution at a future point in time</summary> /// <summary>Schedules actions for execution at a future point in time</summary>
@ -77,7 +75,7 @@ namespace Nuclex.Support.Scheduling {
long intervalTicks, long intervalTicks,
long nextDueTicks, long nextDueTicks,
DateTime absoluteUtcTime, DateTime absoluteUtcTime,
Delegate callback WaitCallback callback
) { ) {
this.IntervalTicks = intervalTicks; this.IntervalTicks = intervalTicks;
this.NextDueTicks = nextDueTicks; this.NextDueTicks = nextDueTicks;
@ -100,7 +98,7 @@ namespace Nuclex.Support.Scheduling {
/// </remarks> /// </remarks>
public DateTime AbsoluteUtcTime; public DateTime AbsoluteUtcTime;
/// <summary>Callback that will be invoked when the notification is due</summary> /// <summary>Callback that will be invoked when the notification is due</summary>
public Delegate Callback; public WaitCallback Callback;
/// <summary>Whether the notification has been cancelled</summary> /// <summary>Whether the notification has been cancelled</summary>
public bool Cancelled; public bool Cancelled;
@ -108,14 +106,44 @@ namespace Nuclex.Support.Scheduling {
#endregion // class Notification #endregion // class Notification
#region class NotificationComparer
/// <summary>Compares two notifications to each other</summary>
private class NotificationComparer : IComparer<Notification> {
/// <summary>The default instance of the notification comparer</summary>
public static readonly NotificationComparer Default = new NotificationComparer();
/// <summary>Compares two notifications to each other based on their time</summary>
/// <param name="left">Notification that will be compared on the left side</param>
/// <param name="right">Notification that will be comapred on the right side</param>
/// <returns>The relation of the two notification's times to each other</returns>
public int Compare(Notification left, Notification right) {
if(left.NextDueTicks > right.NextDueTicks) {
return -1;
} else if(left.NextDueTicks < right.NextDueTicks) {
return 1;
} else {
return 0;
}
}
#endregion // class NotificationComparer
}
/// <summary>Initializes a new scheduler using the default time source</summary> /// <summary>Initializes a new scheduler using the default time source</summary>
public Scheduler() : this(DefaultTimeSource) { } public Scheduler() : this(DefaultTimeSource) { }
/// <summary>Initializes a new scheduler using the specified time source</summary> /// <summary>Initializes a new scheduler using the specified time source</summary>
/// <param name="timeSource">Source source the scheduler will use</param> /// <param name="timeSource">Source source the scheduler will use</param>
public Scheduler(ITimeSource timeSource) { public Scheduler(ITimeSource timeSource) {
this.dateTimeAdjustedDelegate = new EventHandler(dateTimeAdjusted);
this.timeSource = timeSource; this.timeSource = timeSource;
this.notifications = new PriorityQueue<Notification>(); this.timeSource.DateTimeAdjusted += this.dateTimeAdjustedDelegate;
this.notifications = new PriorityQueue<Notification>(NotificationComparer.Default);
this.notificationWaitEvent = new AutoResetEvent(false); this.notificationWaitEvent = new AutoResetEvent(false);
this.timerThread = new Thread(new ThreadStart(runTimerThread)); this.timerThread = new Thread(new ThreadStart(runTimerThread));
@ -138,6 +166,13 @@ namespace Nuclex.Support.Scheduling {
this.timerThread.Join(2500), "Scheduler timer thread did not exit in time" this.timerThread.Join(2500), "Scheduler timer thread did not exit in time"
); );
// Unsubscribe from the time source to avoid surprise events during or
// after shutdown
if(this.timeSource != null) {
this.timeSource.DateTimeAdjusted -= this.dateTimeAdjustedDelegate;
this.timeSource = null;
}
// Get rid of the notification wait event now that we've made sure that // Get rid of the notification wait event now that we've made sure that
// the timer thread is down. // the timer thread is down.
this.notificationWaitEvent.Close(); this.notificationWaitEvent.Close();
@ -145,7 +180,6 @@ namespace Nuclex.Support.Scheduling {
// Help the GC a bit // Help the GC a bit
this.notificationWaitEvent = null; this.notificationWaitEvent = null;
this.notifications = null; this.notifications = null;
this.timeSource = null;
// Set to null so we don't attempt to end the thread again if Dispose() is // Set to null so we don't attempt to end the thread again if Dispose() is
// called multiple times. // called multiple times.
@ -168,7 +202,7 @@ namespace Nuclex.Support.Scheduling {
/// the notification. So if you need to be notified after a fixed time, use /// the notification. So if you need to be notified after a fixed time, use
/// the NotifyIn() method instead. /// the NotifyIn() method instead.
/// </remarks> /// </remarks>
public object NotifyAt(DateTime notificationTime, Delegate callback) { public object NotifyAt(DateTime notificationTime, WaitCallback callback) {
if(notificationTime.Kind == DateTimeKind.Unspecified) { if(notificationTime.Kind == DateTimeKind.Unspecified) {
throw new ArgumentException( throw new ArgumentException(
"Notification time is neither UTC or local", "notificationTime" "Notification time is neither UTC or local", "notificationTime"
@ -176,7 +210,9 @@ namespace Nuclex.Support.Scheduling {
} }
DateTime notificationTimeUtc = notificationTime.ToUniversalTime(); DateTime notificationTimeUtc = notificationTime.ToUniversalTime();
long remainingTicks = notificationTimeUtc.Ticks - DateTime.UtcNow.Ticks; DateTime now = this.timeSource.CurrentUtcTime;
long remainingTicks = notificationTimeUtc.Ticks - now.Ticks;
long nextDueTicks = this.timeSource.Ticks + remainingTicks; long nextDueTicks = this.timeSource.Ticks + remainingTicks;
return scheduleNotification( return scheduleNotification(
@ -195,7 +231,7 @@ namespace Nuclex.Support.Scheduling {
/// Callback that will be invoked when the notification is due /// Callback that will be invoked when the notification is due
/// </param> /// </param>
/// <returns>A handle that can be used to cancel the notification</returns> /// <returns>A handle that can be used to cancel the notification</returns>
public object NotifyIn(TimeSpan delay, Delegate callback) { public object NotifyIn(TimeSpan delay, WaitCallback callback) {
return scheduleNotification( return scheduleNotification(
new Notification( new Notification(
0, 0,
@ -216,7 +252,7 @@ namespace Nuclex.Support.Scheduling {
/// Callback that will be invoked when the notification is due /// Callback that will be invoked when the notification is due
/// </param> /// </param>
/// <returns>A handle that can be used to cancel the notification</returns> /// <returns>A handle that can be used to cancel the notification</returns>
public object NotifyIn(int delayMilliseconds, Delegate callback) { public object NotifyIn(int delayMilliseconds, WaitCallback callback) {
return scheduleNotification( return scheduleNotification(
new Notification( new Notification(
0, 0,
@ -236,7 +272,7 @@ namespace Nuclex.Support.Scheduling {
/// Callback that will be invoked when the notification is due /// Callback that will be invoked when the notification is due
/// </param> /// </param>
/// <returns>A handle that can be used to cancel the notification</returns> /// <returns>A handle that can be used to cancel the notification</returns>
public object NotifyEach(TimeSpan delay, TimeSpan interval, Delegate callback) { public object NotifyEach(TimeSpan delay, TimeSpan interval, WaitCallback callback) {
return scheduleNotification( return scheduleNotification(
new Notification( new Notification(
interval.Ticks, interval.Ticks,
@ -261,7 +297,7 @@ namespace Nuclex.Support.Scheduling {
/// </param> /// </param>
/// <returns>A handle that can be used to cancel the notification</returns> /// <returns>A handle that can be used to cancel the notification</returns>
public object NotifyEach( public object NotifyEach(
int delayMilliseconds, int intervalMilliseconds, Delegate callback int delayMilliseconds, int intervalMilliseconds, WaitCallback callback
) { ) {
return scheduleNotification( return scheduleNotification(
new Notification( new Notification(
@ -273,6 +309,17 @@ namespace Nuclex.Support.Scheduling {
); );
} }
/// <summary>Cancels a scheduled notification</summary>
/// <param name="notificationHandle">
/// Handle of the notification that will be cancelled
/// </param>
public void Cancel(object notificationHandle) {
Notification notification = notificationHandle as Notification;
if(notification != null) {
notification.Cancelled = true;
}
}
/// <summary>Returns the default time source for the scheduler</summary> /// <summary>Returns the default time source for the scheduler</summary>
public static ITimeSource DefaultTimeSource { public static ITimeSource DefaultTimeSource {
get { return TimeSourceSingleton.Instance; } get { return TimeSourceSingleton.Instance; }
@ -297,11 +344,54 @@ namespace Nuclex.Support.Scheduling {
return CreateTimeSource(WindowsTimeSource.Available); return CreateTimeSource(WindowsTimeSource.Available);
} }
/// <summary>Called when the system date/time have been adjusted</summary>
/// <param name="sender">Time source which detected the adjustment</param>
/// <param name="arguments">Not used</param>
private void dateTimeAdjusted(object sender, EventArgs arguments) {
lock(this.timerThread) {
long currentTicks = this.timeSource.Ticks;
DateTime currentTime = this.timeSource.CurrentUtcTime;
PriorityQueue<Notification> updatedQueue = new PriorityQueue<Notification>(
NotificationComparer.Default
);
// Copy all notifications from the original queue to a new one, adjusting
// those with an absolute notification time along the way to a new due tick
while(this.notifications.Count > 0) {
Notification notification = this.notifications.Dequeue();
if(!notification.Cancelled) {
// If this notification has an absolute due time, adjust its due tick
if(notification.AbsoluteUtcTime != DateTime.MinValue) {
// Combining recurrent notifications with absolute time isn't allowed
Debug.Assert(notification.IntervalTicks == 0);
// Make the adjustment
long remainingTicks = (notification.AbsoluteUtcTime - currentTime).Ticks;
notification.NextDueTicks = currentTicks + remainingTicks;
}
// Notification processed, move it over to the next priority queue
updatedQueue.Enqueue(notification);
}
}
// Replace the working queue with the update queue
this.notifications = updatedQueue;
}
this.notificationWaitEvent.Set();
}
/// <summary>Schedules a notification for processing by the timer thread</summary> /// <summary>Schedules a notification for processing by the timer thread</summary>
/// <param name="notification">Notification that will be scheduled</param> /// <param name="notification">Notification that will be scheduled</param>
/// <returns>The scheduled notification</returns> /// <returns>The scheduled notification</returns>
private object scheduleNotification(Notification notification) { private object scheduleNotification(Notification notification) {
lock(this.notifications) { lock(this.timerThread) {
this.notifications.Enqueue(notification); this.notifications.Enqueue(notification);
// If this notification has become that next due notification, wake up // If this notification has become that next due notification, wake up
@ -316,12 +406,15 @@ namespace Nuclex.Support.Scheduling {
/// <summary>Executes the timer thread</summary> /// <summary>Executes the timer thread</summary>
private void runTimerThread() { private void runTimerThread() {
Notification nextDueNotification;
lock(this.timerThread) {
nextDueNotification = getNextDueNotification();
}
// Keep processing notifications until we're told to quit
for(; ; ) { for(; ; ) {
// Get the notification that is due next and wait for it. When no notifications // Wait until the nextmost notification is due or something else wakes us up
// are queued, wait indefinitely until we're signalled
Notification nextDueNotification = getNextDueNotification();
if(nextDueNotification == null) { if(nextDueNotification == null) {
this.notificationWaitEvent.WaitOne(); this.notificationWaitEvent.WaitOne();
} else { } else {
@ -334,17 +427,42 @@ namespace Nuclex.Support.Scheduling {
break; break;
} }
// Process all notifications that are due by handing them over to the thread pool.
//if(nextDueNotification.AbsoluteUtcTime != // The notification queue might have been updated while we were sleeping, so
// look for the notification that is due next again
long ticks = this.timeSource.Ticks;
lock(this.timerThread) {
for(; ; ) {
nextDueNotification = getNextDueNotification();
if(nextDueNotification == null) {
break;
} }
// If the next notification is more than a millisecond away, we've reached
// the end of the notifications we need to process.
long remainingTicks = (nextDueNotification.NextDueTicks - ticks);
if(remainingTicks >= TicksPerMillisecond) {
break;
}
if(!nextDueNotification.Cancelled) {
ThreadPool.QueueUserWorkItem(nextDueNotification.Callback);
}
this.notifications.Dequeue();
if(nextDueNotification.IntervalTicks != 0) {
nextDueNotification.NextDueTicks += nextDueNotification.IntervalTicks;
this.notifications.Enqueue(nextDueNotification);
}
} // for
} // lock
} // for
} }
/// <summary>Retrieves the notification that is due next</summary> /// <summary>Retrieves the notification that is due next</summary>
/// <returns>The notification that is due next</returns> /// <returns>The notification that is due next</returns>
private Notification getNextDueNotification() { private Notification getNextDueNotification() {
lock(this.notifications) {
if(this.notifications.Count == 0) { if(this.notifications.Count == 0) {
return null; return null;
} else { } else {
@ -353,10 +471,10 @@ namespace Nuclex.Support.Scheduling {
this.notifications.Dequeue(); this.notifications.Dequeue();
nextDueNotification = this.notifications.Peek(); nextDueNotification = this.notifications.Peek();
} }
return nextDueNotification; return nextDueNotification;
} }
} }
}
/// <summary>Time source used by the scheduler</summary> /// <summary>Time source used by the scheduler</summary>
private ITimeSource timeSource; private ITimeSource timeSource;
@ -370,8 +488,9 @@ namespace Nuclex.Support.Scheduling {
/// <summary>Whether the timer thread should end</summary> /// <summary>Whether the timer thread should end</summary>
private volatile bool endRequested; private volatile bool endRequested;
/// <summary>Delegate for the dateTimeAdjusted() method</summary>
private EventHandler dateTimeAdjustedDelegate;
} }
} // namespace Nuclex.Support.Scheduling } // namespace Nuclex.Support.Scheduling
#endif

View File

@ -18,13 +18,13 @@ License along with this library
*/ */
#endregion #endregion
#if !XBOX360
using System; using System;
using System.Collections.Generic; using System.Collections.Generic;
using System.Threading; using System.Threading;
#if !XBOX360
using Microsoft.Win32; using Microsoft.Win32;
#endif
namespace Nuclex.Support.Scheduling { namespace Nuclex.Support.Scheduling {
@ -38,16 +38,24 @@ namespace Nuclex.Support.Scheduling {
/// <summary>Initializes a new Windows time source</summary> /// <summary>Initializes a new Windows time source</summary>
public WindowsTimeSource() { public WindowsTimeSource() {
#if XBOX360
throw new InvalidOperationException(
"Windows time source is not available on the XBox 360"
);
#else
this.onDateTimeAdjustedDelegate = new EventHandler(OnDateTimeAdjusted); this.onDateTimeAdjustedDelegate = new EventHandler(OnDateTimeAdjusted);
SystemEvents.TimeChanged += this.onDateTimeAdjustedDelegate; SystemEvents.TimeChanged += this.onDateTimeAdjustedDelegate;
#endif
} }
/// <summary>Immediately releases all resources owned by the instance</summary> /// <summary>Immediately releases all resources owned by the instance</summary>
public void Dispose() { public void Dispose() {
#if !XBOX360
if(this.onDateTimeAdjustedDelegate != null) { if(this.onDateTimeAdjustedDelegate != null) {
SystemEvents.TimeChanged -= this.onDateTimeAdjustedDelegate; SystemEvents.TimeChanged -= this.onDateTimeAdjustedDelegate;
this.onDateTimeAdjustedDelegate = null; this.onDateTimeAdjustedDelegate = null;
} }
#endif
} }
/// <summary>Waits for an AutoResetEvent to become signalled</summary> /// <summary>Waits for an AutoResetEvent to become signalled</summary>
@ -57,7 +65,7 @@ namespace Nuclex.Support.Scheduling {
/// True if the WaitHandle was signalled, false if the timeout was reached /// True if the WaitHandle was signalled, false if the timeout was reached
/// </returns> /// </returns>
public override bool WaitOne(AutoResetEvent waitHandle, long ticks) { public override bool WaitOne(AutoResetEvent waitHandle, long ticks) {
return waitHandle.WaitOne((int)(ticks / TicksPerMillisecond)); return waitHandle.WaitOne((int)(ticks / TicksPerMillisecond), false);
} }
/// <summary> /// <summary>
@ -73,5 +81,3 @@ namespace Nuclex.Support.Scheduling {
} }
} // namespace Nuclex.Support.Scheduling } // namespace Nuclex.Support.Scheduling
#endif // !XBOX360