Proxy-factory to single instance per lifetime, if possible

src/Injectio.Attributes/RegistrationStrategy.cs

@@ -16,5 +16,11 @@ public enum RegistrationStrategy
     /// <summary>
     /// Registers each matching concrete type as all of its implemented interfaces and itself
     /// </summary>
-    SelfWithInterfaces = 2
+    SelfWithInterfaces = 2,
+    /// <summary>
+    /// Registers each matching concrete type as all of its implemented interfaces and itself.
+    /// For the interfaces a proxy-factory resolves the service from its type-name, so only one instance is created per lifetime
+    /// </summary>
+    /// <remarks>For open-generic registrations, this behaves like <see cref="SelfWithInterfaces"/></remarks>
+    SelfWithProxyFactory = 3
 }

src/Injectio.Generators/KnownTypes.cs

@@ -37,29 +37,33 @@ public static class KnownTypes
     public const string ServiceLifetimeTransientFullName = "Microsoft.Extensions.DependencyInjection.ServiceLifetime.Transient";
 
 
-    public static readonly int DuplicateStrategySkipValue = 0;
+    public const int DuplicateStrategySkipValue = 0;
     public const string DuplicateStrategySkipShortName = "Skip";
     public const string DuplicateStrategySkipTypeName = $"DuplicateStrategy.{DuplicateStrategySkipShortName}";
 
-    public static readonly int DuplicateStrategyReplaceValue = 1;
+    public const int DuplicateStrategyReplaceValue = 1;
     public const string DuplicateStrategyReplaceShortName = "Replace";
     public const string DuplicateStrategyReplaceTypeName = $"DuplicateStrategy.{DuplicateStrategyReplaceShortName}";
 
-    public static readonly int DuplicateStrategyAppendValue = 2;
+    public const int DuplicateStrategyAppendValue = 2;
     public const string DuplicateStrategyAppendShortName = "Append";
     public const string DuplicateStrategyAppendTypeName = $"DuplicateStrategy.{DuplicateStrategyAppendShortName}";
 
 
-    public static readonly int RegistrationStrategySelfValue = 0;
+    public const int RegistrationStrategySelfValue = 0;
     public const string RegistrationStrategySelfShortName = "Self";
     public const string RegistrationStrategySelfTypeName = $"RegistrationStrategy.{RegistrationStrategySelfShortName}";
 
-    public static readonly int RegistrationStrategyImplementedInterfacesValue = 1;
+    public const int RegistrationStrategyImplementedInterfacesValue = 1;
     public const string RegistrationStrategyImplementedInterfacesShortName = "ImplementedInterfaces";
     public const string RegistrationStrategyImplementedInterfacesTypeName = $"RegistrationStrategy.{RegistrationStrategyImplementedInterfacesShortName}";
 
-    public static readonly int RegistrationStrategySelfWithInterfacesValue = 2;
+    public const int RegistrationStrategySelfWithInterfacesValue = 2;
     public const string RegistrationStrategySelfWithInterfacesShortName = "SelfWithInterfaces";
     public const string RegistrationStrategySelfWithInterfacesTypeName = $"RegistrationStrategy.{RegistrationStrategySelfWithInterfacesShortName}";
 
+    public const int RegistrationStrategySelfWithProxyFactoryValue = 3;
+    public const string RegistrationStrategySelfWithProxyFactoryShortName = "SelfWithProxyFactory";
+    public const string RegistrationStrategySelfWithProxyFactoryTypeName = $"RegistrationStrategy.{RegistrationStrategySelfWithProxyFactoryShortName}";
+
 }

src/Injectio.Generators/ServiceRegistrationGenerator.cs

@@ -336,7 +336,7 @@ private static (EquatableArray<Diagnostic> diagnostics, bool hasServiceCollectio
             && implementationType == null
             && serviceTypes.Count == 0)
         {
-            registrationStrategy = KnownTypes.RegistrationStrategySelfWithInterfacesShortName;
+            registrationStrategy = KnownTypes.RegistrationStrategySelfWithProxyFactoryShortName;
         }
 
         // no implementation type set, use class attribute is on
@@ -348,7 +348,9 @@ private static (EquatableArray<Diagnostic> diagnostics, bool hasServiceCollectio
         }
 
         // add implemented interfaces
-        bool includeInterfaces = registrationStrategy is KnownTypes.RegistrationStrategyImplementedInterfacesShortName or KnownTypes.RegistrationStrategySelfWithInterfacesShortName;
+        bool includeInterfaces = registrationStrategy is KnownTypes.RegistrationStrategyImplementedInterfacesShortName
+            or KnownTypes.RegistrationStrategySelfWithInterfacesShortName
+            or KnownTypes.RegistrationStrategySelfWithProxyFactoryShortName;
         if (includeInterfaces)
         {
             foreach (var implementedInterface in classSymbol.AllInterfaces)
@@ -366,10 +368,18 @@ private static (EquatableArray<Diagnostic> diagnostics, bool hasServiceCollectio
         }
 
         // add class attribute is on; default service type if not set
-        bool includeSelf = registrationStrategy is KnownTypes.RegistrationStrategySelfShortName or KnownTypes.RegistrationStrategySelfWithInterfacesShortName;
+        bool includeSelf = registrationStrategy is KnownTypes.RegistrationStrategySelfShortName
+            or KnownTypes.RegistrationStrategySelfWithInterfacesShortName
+            or KnownTypes.RegistrationStrategySelfWithProxyFactoryShortName;
         if (includeSelf || serviceTypes.Count == 0)
             serviceTypes.Add(implementationType!);
 
+        if (registrationStrategy is null && serviceTypes.Contains(implementationType!))
+            registrationStrategy = KnownTypes.RegistrationStrategySelfWithProxyFactoryShortName;
+
+        if (registrationStrategy is KnownTypes.RegistrationStrategySelfWithProxyFactoryShortName && isOpenGeneric)
+            registrationStrategy = KnownTypes.RegistrationStrategySelfWithInterfacesShortName;
+
         return new ServiceRegistration(
             Lifetime: serviceLifetime,
             ImplementationType: implementationType!,
@@ -529,9 +539,9 @@ private static string ResolveDuplicateStrategy(object? value)
         {
             int v => v switch
             {
-                0 => KnownTypes.DuplicateStrategySkipShortName,
-                1 => KnownTypes.DuplicateStrategyReplaceShortName,
-                2 => KnownTypes.DuplicateStrategyAppendShortName,
+                KnownTypes.DuplicateStrategySkipValue => KnownTypes.DuplicateStrategySkipShortName,
+                KnownTypes.DuplicateStrategyReplaceValue => KnownTypes.DuplicateStrategyReplaceShortName,
+                KnownTypes.DuplicateStrategyAppendValue => KnownTypes.DuplicateStrategyAppendShortName,
                 _ => KnownTypes.DuplicateStrategySkipShortName
             },
             string text => text,
@@ -545,13 +555,14 @@ private static string ResolveRegistrationStrategy(object? value)
         {
             int v => v switch
             {
-                0 => KnownTypes.RegistrationStrategySelfShortName,
-                1 => KnownTypes.RegistrationStrategyImplementedInterfacesShortName,
-                2 => KnownTypes.RegistrationStrategySelfWithInterfacesShortName,
-                _ => KnownTypes.RegistrationStrategySelfWithInterfacesShortName
+                KnownTypes.RegistrationStrategySelfValue => KnownTypes.RegistrationStrategySelfShortName,
+                KnownTypes.RegistrationStrategyImplementedInterfacesValue => KnownTypes.RegistrationStrategyImplementedInterfacesShortName,
+                KnownTypes.RegistrationStrategySelfWithInterfacesValue => KnownTypes.RegistrationStrategySelfWithInterfacesShortName,
+                KnownTypes.RegistrationStrategySelfWithProxyFactoryValue => KnownTypes.RegistrationStrategySelfWithProxyFactoryShortName,
+                _ => KnownTypes.RegistrationStrategySelfWithProxyFactoryShortName
             },
             string text => text,
-            _ => KnownTypes.RegistrationStrategySelfWithInterfacesShortName
+            _ => KnownTypes.RegistrationStrategySelfWithProxyFactoryShortName
         };
     }
 }

src/Injectio.Generators/ServiceRegistrationWriter.cs

@@ -291,6 +291,23 @@ private static void WriteServiceGeneric(
                 .AppendIf(".", !hasNamespace)
                 .Append(serviceRegistration.Factory);
         }
+        else if (serviceRegistration.Registration == KnownTypes.RegistrationStrategySelfWithProxyFactoryShortName
+            && serviceRegistration.ImplementationType != serviceType)
+        {
+            codeBuilder
+                .AppendIf(", ", serviceRegistration.ServiceKey.HasValue())
+                .Append("(serviceProvider")
+                .AppendIf(", key", serviceRegistration.ServiceKey.HasValue())
+                .Append(") => global::Microsoft.Extensions.DependencyInjection.ServiceProvider")
+                .Append(serviceRegistration.ServiceKey.HasValue()
+                    ? "KeyedServiceExtensions.GetRequiredKeyedService<"
+                    : "ServiceExtensions.GetRequiredService<")
+                .AppendIf("global::", !serviceRegistration.ImplementationType.StartsWith("global::"))
+                .Append(serviceRegistration.ImplementationType)
+                .Append(">(serviceProvider")
+                .AppendIf(", key", serviceRegistration.ServiceKey.HasValue())
+                .Append(")");
+        }
 
         codeBuilder
             .AppendLine(")")

tests/Injectio.Tests/Snapshots/ServiceRegistrationGeneratorTests.GenerateRegisterScopedSelfWithInterfaces.verified.txt

@@ -20,7 +20,7 @@ namespace Microsoft.Extensions.DependencyInjection
 
             global::Microsoft.Extensions.DependencyInjection.Extensions.ServiceCollectionDescriptorExtensions.TryAdd(
                 serviceCollection,
-                global::Microsoft.Extensions.DependencyInjection.ServiceDescriptor.Scoped<global::Injectio.Sample.IService, global::Injectio.Sample.SingletonService>()
+                global::Microsoft.Extensions.DependencyInjection.ServiceDescriptor.Scoped<global::Injectio.Sample.IService, global::Injectio.Sample.SingletonService>((serviceProvider) => global::Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService<global::Injectio.Sample.SingletonService>(serviceProvider))
             );
 
             global::Microsoft.Extensions.DependencyInjection.Extensions.ServiceCollectionDescriptorExtensions.TryAdd(

tests/Injectio.Tests/Snapshots/ServiceRegistrationGeneratorTests.GenerateRegisterSingletonSelfAsClosedGeneric.verified.txt

@@ -20,7 +20,7 @@ namespace Microsoft.Extensions.DependencyInjection
 
             global::Microsoft.Extensions.DependencyInjection.Extensions.ServiceCollectionDescriptorExtensions.TryAdd(
                 serviceCollection,
-                global::Microsoft.Extensions.DependencyInjection.ServiceDescriptor.Singleton<global::Injectio.Sample.IClosedGeneric<object>, global::Injectio.Sample.Service>()
+                global::Microsoft.Extensions.DependencyInjection.ServiceDescriptor.Singleton<global::Injectio.Sample.IClosedGeneric<object>, global::Injectio.Sample.Service>((serviceProvider) => global::Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService<global::Injectio.Sample.Service>(serviceProvider))
             );
 
             global::Microsoft.Extensions.DependencyInjection.Extensions.ServiceCollectionDescriptorExtensions.TryAdd(

tests/Injectio.Tests/Snapshots/ServiceRegistrationGeneratorTests.GenerateRegisterSingletonTags.verified.txt

@@ -22,7 +22,7 @@ namespace Microsoft.Extensions.DependencyInjection
             {
                 global::Microsoft.Extensions.DependencyInjection.Extensions.ServiceCollectionDescriptorExtensions.TryAdd(
                     serviceCollection,
-                    global::Microsoft.Extensions.DependencyInjection.ServiceDescriptor.Singleton<global::Injectio.Sample.IServiceTag, global::Injectio.Sample.ServiceTag>()
+                    global::Microsoft.Extensions.DependencyInjection.ServiceDescriptor.Singleton<global::Injectio.Sample.IServiceTag, global::Injectio.Sample.ServiceTag>((serviceProvider) => global::Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService<global::Injectio.Sample.ServiceTag>(serviceProvider))
                 );
 
                 global::Microsoft.Extensions.DependencyInjection.Extensions.ServiceCollectionDescriptorExtensions.TryAdd(

tests/Injectio.Tests/Snapshots/ServiceRegistrationGeneratorTests.GenerateRegisterTransientSelfWithInterfaces.verified.txt

@@ -20,7 +20,7 @@ namespace Microsoft.Extensions.DependencyInjection
 
             global::Microsoft.Extensions.DependencyInjection.Extensions.ServiceCollectionDescriptorExtensions.TryAdd(
                 serviceCollection,
-                global::Microsoft.Extensions.DependencyInjection.ServiceDescriptor.Transient<global::Injectio.Sample.IService, global::Injectio.Sample.SingletonService>()
+                global::Microsoft.Extensions.DependencyInjection.ServiceDescriptor.Transient<global::Injectio.Sample.IService, global::Injectio.Sample.SingletonService>((serviceProvider) => global::Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService<global::Injectio.Sample.SingletonService>(serviceProvider))
             );
 
             global::Microsoft.Extensions.DependencyInjection.Extensions.ServiceCollectionDescriptorExtensions.TryAdd(