Expanded upon EventScheduler

- Events are now sorted
- Thread waits until either a new event is scheduled or an existing
event is ready before continuing.

TrueCraft.API/Server/IEventScheduler.cs

@@ -5,6 +5,7 @@ namespace TrueCraft.API.Server
     public interface IEventScheduler
     {
         void ScheduleEvent(DateTime when, Action<IMultiplayerServer> action);
-        void Update();
+        void Start();
+        void Stop();
     }
 }

TrueCraft/EventScheduler.cs

@@ -1,17 +1,23 @@
 using System;
 using TrueCraft.API.Server;
 using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using TrueCraft.API.Logging;
 
 namespace TrueCraft
 {
     public class EventScheduler : IEventScheduler
     {
-        // TODO: This could be done more efficiently if the list were kept sorted
-        
-        private IList<ScheduledEvent> Events { get; set; }
+        private List<ScheduledEvent> Events { get; set; }
         private object EventLock = new object();
         private IMultiplayerServer Server { get; set; }
 
+        private SemaphoreSlim Sem = new SemaphoreSlim(0, 1);
+
+        private CancellationTokenSource Cancel;
+
         public EventScheduler(IMultiplayerServer server)
         {
             Events = new List<ScheduledEvent>();
@@ -24,30 +30,99 @@ namespace TrueCraft
             {
                 Events.Add(new ScheduledEvent { When = when, Action = action });
             }
+
+            if (Sem.CurrentCount == 0)
+                Sem.Release();
         }
 
-        public void Update()
+        public void Start()
         {
-            lock (EventLock)
+            Cancel = new CancellationTokenSource();
+
+            Thread scheduleThread = new Thread(Update);
+            scheduleThread.IsBackground = true;
+
+            scheduleThread.Start();
+        }
+
+        public void Stop()
+        {
+            Cancel.Cancel();
+        }
+
+        private void Update()
+        {
+            while (true)
             {
-                var start = DateTime.Now;
-                for (int i = 0; i < Events.Count; i++)
+                if (Cancel.IsCancellationRequested)
+                    break;
+
+                try
                 {
-                    var e = Events[i];
-                    if (e.When <= start)
+                    ScheduledEvent? nextEvent = null;
+                    lock (EventLock)
                     {
-                        e.Action(Server);
-                        Events.RemoveAt(i);
-                        i--;
+                        var evts = Events.ToList();
+                        evts.Sort();
+
+                        DateTime now = DateTime.Now;
+                        for (int i = 0; i < evts.Count; i++)
+                        {
+                            ScheduledEvent evt = evts[i];
+
+                            if (evt.When < now)
+                                break;
+
+                            evts.RemoveAt(i);
+                            i--;
+
+                            evt.Action(Server);
+                        }
+
+                        if (evts.Count > 0)
+                            nextEvent = evts.First();
+
+                        Events = evts;
                     }
+
+                    var tasks = new List<Task> { Sem.WaitAsync(Cancel.Token) };
+                    if (nextEvent != null)
+                    {
+                        TimeSpan ts = nextEvent.Value.When - DateTime.Now;
+
+                        if (ts < TimeSpan.Zero)
+                            continue;
+
+                        tasks.Add(Task.Delay(ts, Cancel.Token));
+                    }
+                    
+                    Task.WhenAny(tasks).Wait();
+                }
+                catch (OperationCanceledException)
+                {
+                    return;
+                }
+                catch (Exception ex)
+                {
+                    Server.Log(LogCategory.Error, "Scheduler Error", ex.ToString());
                 }
             }
         }
 
-        private struct ScheduledEvent
+        private struct ScheduledEvent : IComparable<ScheduledEvent>
         {
             public DateTime When;
             public Action<IMultiplayerServer> Action;
+
+            public int CompareTo(ScheduledEvent other)
+            {
+                if (When > other.When)
+                    return 1;
+                if (When == other.When)
+                    return 0;
+
+                return -1;
+            }
         }
     }
 }

TrueCraft/MultiplayerServer.cs

@@ -113,6 +113,8 @@ namespace TrueCraft
             Listener.Start();
             EndPoint = (IPEndPoint)Listener.LocalEndpoint;
 
+            Scheduler.Start();
+
             SocketAsyncEventArgs args = new SocketAsyncEventArgs();
             args.Completed += AcceptClient;
 
@@ -135,6 +137,8 @@ namespace TrueCraft
                 w.Save();
             foreach (var c in Clients)
                 DisconnectClient(c);
+
+            Scheduler.Stop();
         }
 
         public void AddWorld(IWorld world)
@@ -294,7 +298,6 @@ namespace TrueCraft
         {
             if (ShuttingDown)
                 return;
-            Scheduler.Update();
             foreach (var manager in EntityManagers)
             {
                 manager.Update();

TrueCraft/TrueCraft.csproj

@@ -9,6 +9,8 @@
     <AssemblyName>TrueCraft</AssemblyName>
     <ProductVersion>8.0.30703</ProductVersion>
     <SchemaVersion>2.0</SchemaVersion>
+    <TargetFrameworkVersion>v4.5</TargetFrameworkVersion>
+    <TargetFrameworkProfile />
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
     <Optimize>false</Optimize>
@@ -16,11 +18,13 @@
     <WarningLevel>4</WarningLevel>
     <DebugSymbols>true</DebugSymbols>
     <ConsolePause>false</ConsolePause>
+    <Prefer32Bit>false</Prefer32Bit>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <Optimize>false</Optimize>
     <OutputPath>bin\Release</OutputPath>
     <WarningLevel>4</WarningLevel>
+    <Prefer32Bit>false</Prefer32Bit>
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
@@ -75,6 +79,7 @@
     </ProjectReference>
   </ItemGroup>
   <ItemGroup>
+    <None Include="app.config" />
     <None Include="packages.config" />
   </ItemGroup>
 </Project>

TrueCraft/app.config

@@ -0,0 +1,3 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+<startup><supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5"/></startup></configuration>