Merge pull request #17 from dotnet-campus/t/lindexi/ChuneleabiLacemcerebawhay

支持.NET 4.5 版本

Author: kkwpsv

AsyncWorkerCollection/AsyncAutoResetEvent.cs

@@ -19,7 +19,13 @@ public AsyncAutoResetEvent(bool initialState)
             _isSignaled = initialState;
         }
 
-        private static readonly Task CompletedSourceTask = Task.FromResult(true);
+        private static readonly Task CompletedSourceTask
+#if NETFRAMEWORK
+            = Task.FromResult(true);
+#else
+            = Task.CompletedTask;
+#endif
+
 
         /// <summary>
         /// 异步等待一个信号，需要await
@@ -31,6 +37,8 @@ public Task WaitOneAsync()
             {
                 if (_isSignaled)
                 {
+                    // 按照 AutoResetEvent 的设计，在没有任何等待进入时，如果有设置 Set 方法，那么下一次第一个进入的等待将会通过
+                    // 也就是在没有任何等待时，无论调用多少次 Set 方法，在调用之后只有一个等待通过
                     _isSignaled = false;
                     return CompletedSourceTask;
                 }
@@ -42,7 +50,7 @@ public Task WaitOneAsync()
         }
 
         /// <summary>
-        /// 设置一个信号量，让一个waitone获得信号
+        /// 设置一个信号量，让一个waitone获得信号，每次调用 <see cref="Set"/> 方法最多只有一个等待通过
         /// </summary>
         public void Set()
         {
@@ -71,6 +79,9 @@ public void Set()
         private readonly Queue<TaskCompletionSource<bool>> _waitQueue =
             new Queue<TaskCompletionSource<bool>>();
 
+        /// <summary>
+        /// 用于在没有任何等待时让下一次等待通过
+        /// </summary>
         private bool _isSignaled;
     }
 }

AsyncWorkerCollection/AsyncQueue.cs

@@ -4,6 +4,10 @@
 using System.Threading;
 using System.Threading.Tasks;
 
+#if NETFRAMEWORK
+using ValueTask = System.Threading.Tasks.Task;
+#endif
+
 namespace dotnetCampus.Threading
 {
     /// <summary>

AsyncWorkerCollection/AsyncWorkerCollection.csproj

@@ -1,15 +1,25 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFramework>netcoreapp3.1</TargetFramework>
+        <TargetFrameworks>net45;netcoreapp3.1</TargetFrameworks>
         <RootNamespace>dotnetCampus.Threading</RootNamespace>
         <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
         <AssemblyName>dotnetCampus.AsyncWorkerCollection</AssemblyName>
     </PropertyGroup>
+
+    <ItemGroup Condition="'$(TargetFramework)'!='net45'">
+        <Compile Remove="IAsyncDisposable.cs" />
+        <Compile Remove="ConcurrentQueueExtension.cs" />
+    </ItemGroup>
     <ItemGroup>
-        <PackageReference Include="dotnetCampus.SourceYard" Version="0.1.19099-alpha">
+        <PackageReference Include="dotnetCampus.SourceYard" Version="0.1.19353-alpha">
             <PrivateAssets>all</PrivateAssets>
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
         </PackageReference>
     </ItemGroup>
+    <ItemGroup Condition="'$(TargetFramework)'=='net45'">
+        <PackageReference Include="System.ValueTuple" Version="4.5">
+
+        </PackageReference>
+    </ItemGroup>
 </Project>

AsyncWorkerCollection/ConcurrentQueueExtension.cs

@@ -0,0 +1,21 @@
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace dotnetCampus.Threading
+{
+    static class ConcurrentQueueExtension
+    {
+        // 在 .NET Framework 4.5 没有清理方法
+        public static void Clear<T>(this ConcurrentQueue<T> queue)
+        {
+            while (queue.TryDequeue(out _))
+            {
+                
+            }
+        }
+    }
+}

AsyncWorkerCollection/IAsyncDisposable.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace dotnetCampus.Threading
+{
+    // 这个接口在 .NET Framework 4.5 没有
+    interface IAsyncDisposable
+    {
+    }
+}