Add RegistrationStrategy to skip, append or replace existing services. (

#22)
khellang · Apr 7, 2017 · 451c124 · 451c124
1 parent 0ea37ce
commit 451c124
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Showing 12 changed files with 212 additions and 16 deletions.
diff --git a/src/Scrutor/AssemblySelector.cs b/src/Scrutor/AssemblySelector.cs
@@ -70,7 +70,7 @@ private IImplementationTypeSelector InternalFromAssemblies(IEnumerable<Assembly>
             return AddSelector(assemblies.SelectMany(asm => asm.DefinedTypes).Select(x => x.AsType()));
         }
 
-        void ISelector.Populate(IServiceCollection services)
+        void ISelector.Populate(IServiceCollection services, RegistrationStrategy registrationStrategy)
         {
             if (services == null)
             {
@@ -79,7 +79,7 @@ void ISelector.Populate(IServiceCollection services)
 
             foreach (var selector in Selectors)
             {
-                selector.Populate(services);
+                selector.Populate(services, registrationStrategy);
             }
         }
 

diff --git a/src/Scrutor/AttributeSelector.cs b/src/Scrutor/AttributeSelector.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
@@ -15,13 +15,15 @@ public AttributeSelector(IEnumerable<Type> types)
 
         private IEnumerable<Type> Types { get; }
 
-        void ISelector.Populate(IServiceCollection services)
+        void ISelector.Populate(IServiceCollection services, RegistrationStrategy registrationStrategy)
         {
             if (services == null)
             {
                 throw new ArgumentNullException(nameof(services));
             }
 
+            var strategy = registrationStrategy ?? RegistrationStrategy.Append;
+
             foreach (var type in Types)
             {
                 var typeInfo = type.GetTypeInfo();
@@ -44,7 +46,7 @@ void ISelector.Populate(IServiceCollection services)
                     {
                         var descriptor = new ServiceDescriptor(serviceType, type, attribute.Lifetime);
 
-                        services.Add(descriptor);
+                        strategy.Apply(services, descriptor);
                     }
                 }
             }

diff --git a/src/Scrutor/ISelector.cs b/src/Scrutor/ISelector.cs
@@ -4,6 +4,6 @@ namespace Scrutor
 {
     internal interface ISelector
     {
-        void Populate(IServiceCollection services);
+        void Populate(IServiceCollection services, RegistrationStrategy options);
     }
 }
diff --git a/src/Scrutor/IServiceTypeSelector.cs b/src/Scrutor/IServiceTypeSelector.cs
@@ -59,5 +59,7 @@ public interface IServiceTypeSelector : IImplementationTypeSelector
         /// Registers each matching concrete type according to their <see cref="ServiceDescriptorAttribute"/>.
         /// </summary>
         IImplementationTypeSelector UsingAttributes();
+
+        IServiceTypeSelector UsingRegistrationStrategy(RegistrationStrategy registrationStrategy);
     }
 }
diff --git a/src/Scrutor/ImplementationTypeSelector.cs b/src/Scrutor/ImplementationTypeSelector.cs
@@ -82,7 +82,7 @@ public IServiceTypeSelector AddClasses(Action<IImplementationTypeFilter> action,
             return AddSelector(filter.Types);
         }
 
-        void ISelector.Populate(IServiceCollection services)
+        void ISelector.Populate(IServiceCollection services, RegistrationStrategy registrationStrategy)
         {
             if (services == null)
             {
@@ -96,7 +96,7 @@ void ISelector.Populate(IServiceCollection services)
 
             foreach (var selector in Selectors)
             {
-                selector.Populate(services);
+                selector.Populate(services, registrationStrategy);
             }
         }
 

diff --git a/src/Scrutor/LifetimeSelector.cs b/src/Scrutor/LifetimeSelector.cs
@@ -40,7 +40,7 @@ public IImplementationTypeSelector WithLifetime(ServiceLifetime lifetime)
             return this;
         }
 
-        void ISelector.Populate(IServiceCollection services)
+        void ISelector.Populate(IServiceCollection services, RegistrationStrategy registrationStrategy)
         {
             if (services == null)
             {
@@ -52,6 +52,8 @@ void ISelector.Populate(IServiceCollection services)
                 Lifetime = ServiceLifetime.Transient;
             }
 
+            registrationStrategy = registrationStrategy ?? RegistrationStrategy.Append;
+
             foreach (var typeMap in TypeMaps)
             {
                 foreach (var serviceType in typeMap.ServiceTypes)
@@ -65,7 +67,7 @@ void ISelector.Populate(IServiceCollection services)
 
                     var descriptor = new ServiceDescriptor(serviceType, implementationType, Lifetime.Value);
 
-                    services.Add(descriptor);
+                    registrationStrategy.Apply(services, descriptor);
                 }
             }
         }

diff --git a/src/Scrutor/RegistrationStrategy.cs b/src/Scrutor/RegistrationStrategy.cs
@@ -0,0 +1,57 @@
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+
+namespace Scrutor
+{
+    public abstract class RegistrationStrategy
+    {
+        public static readonly RegistrationStrategy Skip = new SkipRegistrationStrategy();
+
+        public static readonly RegistrationStrategy Append = new AppendRegistrationStrategy();
+
+        public static RegistrationStrategy Replace(ReplacementBehavior behavior = ReplacementBehavior.Default) => new ReplaceRegistrationStrategy(behavior);
+
+        public abstract void Apply(IServiceCollection services, ServiceDescriptor descriptor);
+
+        private sealed class SkipRegistrationStrategy : RegistrationStrategy
+        {
+            public override void Apply(IServiceCollection services, ServiceDescriptor descriptor) => services.TryAdd(descriptor);
+        }
+
+        private sealed class AppendRegistrationStrategy : RegistrationStrategy
+        {
+            public override void Apply(IServiceCollection services, ServiceDescriptor descriptor) => services.Add(descriptor);
+        }
+
+        private sealed class ReplaceRegistrationStrategy : RegistrationStrategy
+        {
+            public ReplaceStrategy(ReplacementBehavior behavior)
+            {
+                Behavior = behavior;
+            }
+
+            private ReplacementBehavior Behavior { get; }
+
+            public override void Apply(IServiceCollection services, ServiceDescriptor descriptor)
+            {
+                var behavior = Behavior;
+
+                if (behavior == ReplacementBehavior.Default)
+                {
+                    behavior = ReplacementBehavior.ServiceType;
+                }
+
+                for (var i = services.Count - 1; i >= 0; i--)
+                {
+                    if ((behavior.HasFlag(ReplacementBehavior.ServiceType) && services[i].ServiceType == descriptor.ServiceType)
+                        || (behavior.HasFlag(ReplacementBehavior.ImplementationType) && services[i].ImplementationType == descriptor.ImplementationType))
+                    {
+                        services.RemoveAt(i);
+                    }
+                }
+
+                services.Add(descriptor);
+            }
+        }
+    }
+}
diff --git a/src/Scrutor/ReplacementBehavior.cs b/src/Scrutor/ReplacementBehavior.cs
@@ -0,0 +1,22 @@
+using System;
+
+namespace Scrutor
+{
+    [Flags]
+    public enum ReplacementBehavior
+    {
+        /// <summary>
+        /// ServiceType only is the default
+        /// </summary>
+        Default = 0,
+        /// <summary>
+        /// Replace by ServiceType (default)
+        /// </summary>
+        ServiceType = 1,
+        /// <summary>
+        /// Replace by ImplementationType.
+        /// </summary>
+        ImplementationType = 2,
+        All = ServiceType | ImplementationType
+    }
+}
diff --git a/src/Scrutor/ServiceCollectionExtensions.Scanning.cs b/src/Scrutor/ServiceCollectionExtensions.Scanning.cs
@@ -29,12 +29,12 @@ public static IServiceCollection Scan(this IServiceCollection services, Action<I
 
             action(selector);
 
-            return services.Populate(selector);
+            return services.Populate(selector, RegistrationStrategy.Append);
         }
 
-        private static IServiceCollection Populate(this IServiceCollection services, ISelector selector)
+        private static IServiceCollection Populate(this IServiceCollection services, ISelector selector, RegistrationStrategy registrationStrategy)
         {
-            selector.Populate(services);
+            selector.Populate(services, registrationStrategy);
             return services;
         }
     }

diff --git a/src/Scrutor/ServiceTypeSelector.cs b/src/Scrutor/ServiceTypeSelector.cs
@@ -8,6 +8,8 @@ namespace Scrutor
 {
     internal class ServiceTypeSelector : ImplementationTypeSelector, IServiceTypeSelector, ISelector
     {
+        private RegistrationStrategy registrationStrategy;
+
         public ServiceTypeSelector(IEnumerable<Type> types) : base(types)
         {
         }
@@ -85,7 +87,7 @@ public IImplementationTypeSelector UsingAttributes()
             return this;
         }
 
-        void ISelector.Populate(IServiceCollection services)
+        void ISelector.Populate(IServiceCollection services, RegistrationStrategy registrationStrategy)
         {
             if (services == null)
             {
@@ -96,13 +98,19 @@ void ISelector.Populate(IServiceCollection services)
             {
                 AsSelf();
             }
-
+            var r = this.registrationStrategy ?? registrationStrategy;
             foreach (var selector in Selectors)
             {
-                selector.Populate(services);
+                selector.Populate(services, r);
             }
         }
 
+        public IServiceTypeSelector UsingRegistrationStrategy(RegistrationStrategy registrationStrategy)
+        {
+            this.registrationStrategy = registrationStrategy;
+            return this;
+        }
+
         private ILifetimeSelector AddSelector(IEnumerable<TypeMap> types)
         {
             var selector = new LifetimeSelector(Types, types);

diff --git a/test/Scrutor.Tests/ScanningTests.cs b/test/Scrutor.Tests/ScanningTests.cs
@@ -10,6 +10,105 @@ public class ScanningTests
     {
         private IServiceCollection Collection { get; } = new ServiceCollection();
 
+        [Fact]
+        public void UsingRegistrationStrategy_None()
+        {
+            Collection.Scan(scan => scan.FromAssemblyOf<ITransientService>()
+                .AddClasses(classes => classes.AssignableTo<ITransientService>())
+                .AsImplementedInterfaces()
+                .WithTransientLifetime());
+
+
+            Collection.Scan(scan => scan.FromAssemblyOf<ITransientService>()
+                .AddClasses(classes => classes.AssignableTo<ITransientService>())
+                .AsImplementedInterfaces()
+                .WithSingletonLifetime());
+
+            var services = Collection.GetDescriptors<ITransientService>();
+
+            Assert.Equal(8, services.Where(x => x.ServiceType == typeof(ITransientService)).Count());
+        }
+
+        [Fact]
+        public void UsingRegistrationStrategy_SkipIfExists()
+        {
+            Collection.Scan(scan => scan.FromAssemblyOf<ITransientService>()
+                .AddClasses(classes => classes.AssignableTo<ITransientService>())
+                .AsImplementedInterfaces()
+                .WithTransientLifetime());
+
+
+            Collection.Scan(scan => scan.FromAssemblyOf<ITransientService>()
+                .AddClasses(classes => classes.AssignableTo<ITransientService>())
+                .UsingRegistrationStrategy(RegistrationStrategy.Skip)
+                .AsImplementedInterfaces()
+                .WithSingletonLifetime());
+
+            var services = Collection.GetDescriptors<ITransientService>();
+
+            Assert.Equal(4, services.Where(x => x.ServiceType == typeof(ITransientService)).Count());
+        }
+
+        [Fact]
+        public void UsingRegistrationStrategy_ReplaceDefault()
+        {
+            Collection.Scan(scan => scan.FromAssemblyOf<ITransientService>()
+                .AddClasses(classes => classes.AssignableTo<ITransientService>())
+                .AsImplementedInterfaces()
+                .WithTransientLifetime());
+
+
+            Collection.Scan(scan => scan.FromAssemblyOf<ITransientService>()
+                .AddClasses(classes => classes.AssignableTo<ITransientService>())
+                .UsingRegistrationStrategy(RegistrationStrategy.Replace(ReplacementBehavior.Default))
+                .AsImplementedInterfaces()
+                .WithSingletonLifetime());
+
+            var services = Collection.GetDescriptors<ITransientService>();
+
+            Assert.Equal(1, services.Where(x => x.ServiceType == typeof(ITransientService)).Count());
+        }
+
+        [Fact]
+        public void UsingRegistrationStrategy_ReplaceServiceTypes()
+        {
+            Collection.Scan(scan => scan.FromAssemblyOf<ITransientService>()
+                .AddClasses(classes => classes.AssignableTo<ITransientService>())
+                .AsImplementedInterfaces()
+                .WithTransientLifetime());
+
+
+            Collection.Scan(scan => scan.FromAssemblyOf<ITransientService>()
+                .AddClasses(classes => classes.AssignableTo<ITransientService>())
+                .UsingRegistrationStrategy(RegistrationStrategy.Replace(ReplacementBehavior.ServiceType))
+                .AsImplementedInterfaces()
+                .WithSingletonLifetime());
+
+            var services = Collection.GetDescriptors<ITransientService>();
+
+            Assert.Equal(1, services.Where(x => x.ServiceType == typeof(ITransientService)).Count());
+        }
+
+        [Fact]
+        public void UsingRegistrationStrategy_ReplaceImplementationTypes()
+        {
+            Collection.Scan(scan => scan.FromAssemblyOf<ITransientService>()
+                .AddClasses(classes => classes.AssignableTo<ITransientService>())
+                .AsImplementedInterfaces()
+                .WithTransientLifetime());
+
+
+            Collection.Scan(scan => scan.FromAssemblyOf<ITransientService>()
+                .AddClasses(classes => classes.AssignableTo<ITransientService>())
+                .UsingRegistrationStrategy(RegistrationStrategy.Replace(ReplacementBehavior.ImplementationType))
+                .AsImplementedInterfaces()
+                .WithSingletonLifetime());
+
+            var services = Collection.GetDescriptors<ITransientService>();
+
+            Assert.Equal(4, services.Where(x => x.ServiceType == typeof(ITransientService)).Count());
+        }
+
         [Fact]
         public void CanFilterTypesToScan()
         {

diff --git a/test/Scrutor.Tests/Scrutor.Tests.csproj b/test/Scrutor.Tests/Scrutor.Tests.csproj
@@ -13,4 +13,8 @@
     <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="1.1.0" />
     <PackageReference Include="xunit" Version="2.2.0" />
   </ItemGroup>
+
+  <ItemGroup>
+    <Service Include="{82a7f48d-3b50-4b1e-b82e-3ada8210c358}" />
+  </ItemGroup>
 </Project>