Merge branch 'release/0.2.1'

Author: David Fallah

GitVersion.yml

@@ -1,4 +1,4 @@
-next-version: 0.2.0
+next-version: 0.2.1
 branches:
   master:
     increment: None

README.md

@@ -62,4 +62,23 @@ public class TemperatureRecorder
 }
 ```
 
+#### Interop with synchronous event handlers
+
+AsyncEvent is meant to allow the specification of events that may need to be handled asynchronously. However, there's potentially a lot of cases where this handling can be purely synchronous, such as if clients simply want to log the event.
+
+AsyncEvent exposes utility functions that allow synchronous event handlers to be adapted for use with asynchronous events. To make use of these, add `using static AsyncEvent.Extensions` in the source code, then wrap synchronous event handlers in `Async(...)` or `Async<TEventArgs>(...)`. For example:
+
+```cs
+using static AsyncEvent.Extensions;
+
+// ...
+
+thermometer.TemperatureChanged += Async<TemperatureChangedEventArgs>(
+    (s, e) => Console.WriteLine($"New temperature: {e.Celcius}°C"));
+```
+
+The adapted event handler will perform the same logic as the synchronous event handler and return a completed task.
+
+#### Examples
+
 Check under `examples/` for complete and runnable example projects.

appveyor.yml

@@ -5,12 +5,13 @@ branches:
   - develop
 install:
   - cinst gitversion.portable -y
+  - ps: dotnet tool install --global dotnet-setversion
 before_build:
   - nuget restore
   - ps: $env:VERSION=$(gitversion /showvariable NuGetVersionV2)
 build_script:
   - ps: dotnet restore
-  - ps: cd src/AsyncEvent; dotnet setversion $env:VERSION; cd ../..
+  - ps: cd src/AsyncEvent; setversion $env:VERSION; cd ../..
   - ps: dotnet build
   - ps: dotnet pack --include-source --include-symbols -c Release -o out/
 test_script:
@@ -22,7 +23,7 @@ deploy:
   provider: NuGet
   skip_symbols: false
   api_key:
-    secure: USCwZe1eILJaDmG30VFhlFWmr2P0G6o0HhUau72/W+TzyAMZyqEfL//vQhfjTSKP
+    secure: u6wyCWr7El0iC167KlsklNSFw5xXBq3WPgegevdthWJfGRHQlCrcxc7AikJh+ePS
   artifact: NuGet packages
   on:
     branch: master

src/AsyncEvent/AsyncEvent.csproj

@@ -11,7 +11,4 @@
     <RepositoryType>git</RepositoryType>
     <RepositoryUrl>https://github.com/TAGC/AsyncEvent</RepositoryUrl>
   </PropertyGroup>
-  <ItemGroup>
-    <DotNetCliToolReference Include="dotnet-setversion" Version="*" />
-  </ItemGroup>
 </Project>

src/AsyncEvent/AsyncEventHandler.cs

@@ -66,8 +66,8 @@ public static AsyncEventHandler<TEventArgs> Async<TEventArgs>(EventHandler<TEven
         /// <param name="sender">The object firing the event.</param>
         /// <param name="eventArgs">The object containing the event data.</param>
         /// <returns>
-        /// A task that completes only when all registered handlers complete. A completed task is returned if the event handler is
-        /// null.
+        /// A <see cref="Task"/> that completes only when all registered handlers complete. A completed task is returned
+        /// if the event handler is <c>null</c>.
         /// </returns>
         public static Task InvokeAsync(this AsyncEventHandler eventHandler, object sender, EventArgs eventArgs)
         {
@@ -89,16 +89,24 @@ public static Task InvokeAsync(this AsyncEventHandler eventHandler, object sende
         /// <param name="eventHandler">This event handler.</param>
         /// <param name="sender">The object firing the event.</param>
         /// <param name="eventArgs">The object containing the event data.</param>
-        /// <returns>A task that completes only when all registered handlers complete.</returns>
+        /// <returns>
+        /// A <see cref="Task"/> that completes only when all registered handlers complete. A completed task is returned
+        /// if the event handler is <c>null</c>.
+        /// </returns>
         public static Task InvokeAsync<TEventArgs>(
             this AsyncEventHandler<TEventArgs> eventHandler,
             object sender,
             TEventArgs eventArgs)
         {
+            if (eventHandler == null)
+            {
+                return Task.CompletedTask;
+            }
+
             var delegates = eventHandler.GetInvocationList().Cast<AsyncEventHandler<TEventArgs>>();
             var tasks = delegates.Select(it => it.Invoke(sender, eventArgs));
 
             return Task.WhenAll(tasks);
         }
     }
-}
+}

test/AsyncEvent.Tests/AsyncEventSpec.cs

@@ -82,13 +82,21 @@ async Task RespondToSomethingHappening(object sender, ExampleEventArgs eventArgs
         }
 
         [Fact]
-        internal void Invoke_Async_Should_Return_Completed_Task_If_No_Handlers_Are_Subscribed()
+        internal void Non_Generic_Invoke_Async_Should_Return_Completed_Task_If_No_Handlers_Are_Subscribed()
         {
             var notifier = new NonGenericNotifier();
 
             notifier.OnSomethingHappening().IsCompleted.ShouldBeTrue();
         }
 
+        [Fact]
+        internal void Generic_Invoke_Async_Should_Return_Completed_Task_If_No_Handlers_Are_Subscribed()
+        {
+            var notifier = new GenericNotifier();
+
+            notifier.OnSomethingHappening(3).IsCompleted.ShouldBeTrue();
+        }
+
         [Fact]
         internal async Task Non_Generic_Async_Event_Should_Run_Asynchronously()
         {
@@ -158,4 +166,4 @@ private class NonGenericNotifier
             public Task OnSomethingHappening() => SomethingHappened.InvokeAsync(this, EventArgs.Empty);
         }
     }
-}
+}