Merge pull request 'Added translators feature' (#8) from Translators into main

Reviewed-on: #8

src.sln

@@ -3,7 +3,9 @@ Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio Version 17
 VisualStudioVersion = 17.0.31903.59
 MinimumVisualStudioVersion = 10.0.40219.1
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ProSol.Messaging", "src\fixMessaging.csproj", "{89203112-653F-4A81-A3B9-9B711E5F6A6B}"
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ProSol.Messaging", "src\Messaging.csproj", "{89203112-653F-4A81-A3B9-9B711E5F6A6B}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Messaging.Tests", "tests\Messaging.Tests.csproj", "{9D9B8827-380D-4AE5-8BA5-F4056935C13A}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -18,5 +20,9 @@ Global
 		{89203112-653F-4A81-A3B9-9B711E5F6A6B}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{89203112-653F-4A81-A3B9-9B711E5F6A6B}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{89203112-653F-4A81-A3B9-9B711E5F6A6B}.Release|Any CPU.Build.0 = Release|Any CPU
+		{9D9B8827-380D-4AE5-8BA5-F4056935C13A}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{9D9B8827-380D-4AE5-8BA5-F4056935C13A}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{9D9B8827-380D-4AE5-8BA5-F4056935C13A}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{9D9B8827-380D-4AE5-8BA5-F4056935C13A}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 EndGlobal

src/IPublisher.cs

@@ -10,5 +10,5 @@ public interface IPublisher<TMessage>
     /// </summary>
     /// <param name="subscriber"> Target. </param>
     /// <returns> Custom IDisposable implementation. </returns>
-    Unsubscriber<TMessage> Subscribe(ISubscriber<TMessage> subscriber);
-}
+    IDisposable Subscribe(ISubscriber<TMessage> subscriber);
+}

src/Messaging.csproj

@@ -7,4 +7,9 @@
     <LangVersion>preview</LangVersion>
   </PropertyGroup>
 
+  <ItemGroup>
+    <AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleToAttribute">
+      <_Parameter1>$(AssemblyName).Tests</_Parameter1>
+    </AssemblyAttribute>
+  </ItemGroup>
 </Project>

src/PipelineMessagePublisher.cs

@@ -1,11 +1,15 @@
-namespace ProSol.Messaging;
+using ProSol.Messaging.Translating;
+
+namespace ProSol.Messaging;
 
 /// <summary>
 /// Collects a subscribers and publishes a messages to them.
 /// Provides a pipeline mechanics, so a subscriber is able to stop message processing.
 /// </summary>
 /// <typeparam name="TMessage"> Type of message. </typeparam>
-public class PipelinePublisher<TMessage> : IPublisher<TMessage>
+public class PipelineMessagePublisher<TMessage> : 
+    IPublisher<TMessage>, 
+    ITranslatorPublisher<TMessage>
 {
     private readonly HashSet<ISubscriber<TMessage>> subscribers = [];
 
@@ -14,12 +18,20 @@ public class PipelinePublisher<TMessage> : IPublisher<TMessage>
     /// </summary>
     /// <param name="subscriber"> An implementation of <see cref="ISubscriber"/> or <see cref="SubscriptionBase"/> interfaces. </param>
     /// <returns> Unsubscriber. </returns>
-    public Unsubscriber<TMessage> Subscribe(ISubscriber<TMessage> subscriber)
+    public IDisposable Subscribe(ISubscriber<TMessage> subscriber)
     {
         subscribers.Add(subscriber);
         return new Unsubscriber<TMessage>(subscribers, subscriber);
     }
 
+    /// <summary>
+    /// Subscribes a subscriber in different message format.
+    /// </summary>
+    public IDisposable Subscribe<TDest>(TranslatorBase<TMessage, TDest> translator)
+    {
+        return Subscribe(translator);
+    }
+
     /// <summary>
     /// Pushes the message to subscribers.
     /// </summary>
@@ -49,7 +61,7 @@ public class PipelinePublisher<TMessage> : IPublisher<TMessage>
             return;
         }
 
-        NextDelegate next = () => PublishInternal(subscribers.Skip(1), message);
+        void next() => PublishInternal(subscribers.Skip(1), message);
         subscribers.First().OnNext(message, next);
     }
 }

src/Translating/ITranslatorPublisher.cs

@@ -0,0 +1,6 @@
+namespace ProSol.Messaging.Translating;
+
+public interface ITranslatorPublisher<TMessage>
+{
+    IDisposable Subscribe<TDest>(TranslatorBase<TMessage, TDest> translatorBase);
+}

src/Translating/SimpleTranslator.cs

@@ -0,0 +1,8 @@
+namespace ProSol.Messaging.Translating;
+
+internal sealed class SimpleTranslator<TSource, TDest>(ISubscriber<TDest> destSubscriber, Func<TSource, TDest> converter) 
+    : TranslatorBase<TSource, TDest>(destSubscriber)
+{
+    protected override TDest ConvertMessage(TSource message)
+        => converter(message);
+}

src/Translating/TranslatorBase.cs

@@ -0,0 +1,17 @@
+namespace ProSol.Messaging.Translating;
+
+public abstract class TranslatorBase<TSource, TDest>(ISubscriber<TDest> destSubscriber) : ISubscriber<TSource>
+{
+    private readonly ISubscriber<TDest> destSubscriber = destSubscriber;
+
+    /// <inheritdoc/>
+    public void OnCompleted() => destSubscriber.OnCompleted();
+
+    /// <inheritdoc/>
+    public void OnNext(TSource message, NextDelegate next) => destSubscriber.OnNext(ConvertMessage(message), next);
+
+    protected abstract TDest ConvertMessage(TSource message);
+
+    public static TranslatorBase<TSource, TDest> Create(ISubscriber<TDest> destSubscriber, Func<TSource, TDest> converter) 
+        => new SimpleTranslator<TSource, TDest>(destSubscriber, converter);
+}

tests/GlobalUsings.cs

@@ -0,0 +1 @@
+global using NUnit.Framework;

tests/MessageTranslatorTests.cs

@@ -0,0 +1,35 @@
+using FakeItEasy;
+using ProSol.Messaging;
+using ProSol.Messaging.Translating;
+
+namespace Messaging.Tests;
+
+public class MessageTranslatorTests
+{
+    [Test]
+    public void SimpleCase_OneToOne_ShouldWork()
+    {
+        // Arrange configs.
+        string[] input = ["Hello", "World!"];
+        int[] expected = [5, 6];
+        static int converter(string message) => message.Length;
+        List<int> messages = [];
+
+        // Arrange operations.
+        var fakeListener = A.Fake<ISubscriber<int>>();
+        A.CallTo(() => fakeListener.OnNext(A<int>._, A<NextDelegate>._))
+         .Invokes((int i, NextDelegate next) => messages.Add(i));
+
+        var publisher = new PipelineMessagePublisher<string>();
+        publisher.Subscribe(TranslatorBase<string, int>.Create(fakeListener, converter));
+
+        // Act.
+        foreach(var item in input)
+        {
+            publisher.Publish(item);
+        }
+
+        // Assert.
+        Assert.That(messages, Is.EquivalentTo(expected));
+    }
+}

tests/Messaging.Tests.csproj

@@ -0,0 +1,25 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+
+    <IsPackable>false</IsPackable>
+    <IsTestProject>true</IsTestProject>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="FakeItEasy" Version="8.0.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.6.0" />
+    <PackageReference Include="NUnit" Version="3.13.3" />
+    <PackageReference Include="NUnit3TestAdapter" Version="4.2.1" />
+    <PackageReference Include="NUnit.Analyzers" Version="3.6.1" />
+    <PackageReference Include="coverlet.collector" Version="6.0.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\src\Messaging.csproj" />
+  </ItemGroup>
+
+</Project>