Optimize DI resolution

Author: commonsensesoftware

src/AspNetCore/WebApi/src/Asp.Versioning.Mvc.ApiExplorer/ApiVersionDescriptionProviderFactory.cs

@@ -10,26 +10,30 @@ namespace Microsoft.AspNetCore.Builder;
 
 internal sealed class ApiVersionDescriptionProviderFactory : IApiVersionDescriptionProviderFactory
 {
-    private readonly IServiceProvider serviceProvider;
+    private readonly ISunsetPolicyManager sunsetPolicyManager;
+    private readonly IApiVersionMetadataCollationProvider[] providers;
+    private readonly IOptions<ApiExplorerOptions> options;
     private readonly Func<IEnumerable<IApiVersionMetadataCollationProvider>, ISunsetPolicyManager, IOptions<ApiExplorerOptions>, IApiVersionDescriptionProvider> activator;
 
     public ApiVersionDescriptionProviderFactory(
-        IServiceProvider serviceProvider,
-        Func<IEnumerable<IApiVersionMetadataCollationProvider>, ISunsetPolicyManager, IOptions<ApiExplorerOptions>, IApiVersionDescriptionProvider> activator )
+        Func<IEnumerable<IApiVersionMetadataCollationProvider>, ISunsetPolicyManager, IOptions<ApiExplorerOptions>, IApiVersionDescriptionProvider> activator,
+        ISunsetPolicyManager sunsetPolicyManager,
+        IEnumerable<IApiVersionMetadataCollationProvider> providers,
+        IOptions<ApiExplorerOptions> options )
     {
-        this.serviceProvider = serviceProvider;
         this.activator = activator;
+        this.sunsetPolicyManager = sunsetPolicyManager;
+        this.providers = providers.ToArray();
+        this.options = options;
     }
 
     public IApiVersionDescriptionProvider Create( EndpointDataSource endpointDataSource )
     {
-        var providers = serviceProvider.GetServices<IApiVersionMetadataCollationProvider>().ToList();
+        var collators = new List<IApiVersionMetadataCollationProvider>( capacity: providers.Length + 1 );
 
-        providers.Insert( 0, new EndpointApiVersionMetadataCollationProvider( endpointDataSource ) );
+        collators.Add( new EndpointApiVersionMetadataCollationProvider( endpointDataSource ) );
+        collators.AddRange( providers );
 
-        var sunsetPolicyManager = serviceProvider.GetRequiredService<ISunsetPolicyManager>();
-        var options = serviceProvider.GetRequiredService<IOptions<ApiExplorerOptions>>();
-
-        return activator( providers, sunsetPolicyManager, options );
+        return activator( collators, sunsetPolicyManager, options );
     }
 }

src/AspNetCore/WebApi/src/Asp.Versioning.Mvc.ApiExplorer/DependencyInjection/IApiVersioningBuilderExtensions.cs

@@ -77,10 +77,16 @@ private static void AddApiExplorerServices( IApiVersioningBuilder builder )
 
     private static IApiVersionDescriptionProviderFactory ResolveApiVersionDescriptionProviderFactory( IServiceProvider serviceProvider )
     {
+        var sunsetPolicyManager = serviceProvider.GetRequiredService<ISunsetPolicyManager>();
+        var providers = serviceProvider.GetServices<IApiVersionMetadataCollationProvider>();
         var options = serviceProvider.GetRequiredService<IOptions<ApiExplorerOptions>>();
         var mightUseCustomGroups = options.Value.FormatGroupName is not null;
 
-        return new ApiVersionDescriptionProviderFactory( serviceProvider, mightUseCustomGroups ? NewGroupedProvider : NewDefaultProvider );
+        return new ApiVersionDescriptionProviderFactory(
+            mightUseCustomGroups ? NewGroupedProvider : NewDefaultProvider,
+            sunsetPolicyManager,
+            providers,
+            options );
 
         static IApiVersionDescriptionProvider NewDefaultProvider(
             IEnumerable<IApiVersionMetadataCollationProvider> providers,