Optimize model builder to improve startup

Author: Chris Martinez

src/Common.OData/AspNet.OData/Builder/VersionedODataModelBuilder.cs

@@ -60,9 +60,26 @@ public Func<ODataModelBuilder> ModelBuilderFactory
         /// value is <c>null</c>.</value>
         public Action<ODataModelBuilder, IEdmModel> OnModelCreated { get; set; }
 
-        IEnumerable<IModelConfiguration> GetMergedConfigurations()
+        /// <summary>
+        /// Builds and returns the sequence of EDM models based on the define model configurations.
+        /// </summary>
+        /// <returns>A <see cref="IEnumerable{T}">sequence</see> of <see cref="IEdmModel">EDM models</see>.</returns>
+        public virtual IEnumerable<IEdmModel> GetEdmModels()
+        {
+            Contract.Ensures( Contract.Result<IEnumerable<IEdmModel>>() != null );
+
+            var apiVersions = GetApiVersions();
+            var configurations = GetMergedConfigurations();
+            var models = new List<IEdmModel>();
+
+            BuildModelPerApiVersion( apiVersions, configurations, models );
+
+            return models;
+        }
+
+        IList<IModelConfiguration> GetMergedConfigurations()
         {
-            Contract.Ensures( Contract.Result<IEnumerable<IModelConfiguration>>() != null );
+            Contract.Ensures( Contract.Result<IList<IModelConfiguration>>() != null );
 
             var defaultConfiguration = DefaultModelConfiguration;
 
@@ -79,19 +96,20 @@ IEnumerable<IModelConfiguration> GetMergedConfigurations()
             return configurations;
         }
 
-        void BuildModelPerApiVersion( IEnumerable<ApiVersion> apiVersions, IEnumerable<IModelConfiguration> configurations, ICollection<IEdmModel> models )
+        void BuildModelPerApiVersion( IReadOnlyList<ApiVersion> apiVersions, IList<IModelConfiguration> configurations, ICollection<IEdmModel> models )
         {
             Contract.Requires( apiVersions != null );
             Contract.Requires( configurations != null );
             Contract.Requires( models != null );
 
-            foreach ( var apiVersion in apiVersions )
+            for ( var i = 0; i < apiVersions.Count; i++ )
             {
+                var apiVersion = apiVersions[i];
                 var builder = ModelBuilderFactory();
 
-                foreach ( var configuration in configurations )
+                for ( var j = 0; j < configurations.Count; j++ )
                 {
-                    configuration.Apply( builder, apiVersion );
+                    configurations[j].Apply( builder, apiVersion );
                 }
 
                 var model = builder.GetEdmModel();

src/Microsoft.AspNet.OData.Versioning/Builder/VersionedODataModelBuilder.cs

@@ -1,6 +1,5 @@
 namespace Microsoft.AspNet.OData.Builder
 {
-    using Microsoft.OData.Edm;
     using Microsoft.Web.Http;
     using Microsoft.Web.Http.Versioning;
     using Microsoft.Web.Http.Versioning.Conventions;
@@ -44,16 +43,14 @@ public VersionedODataModelBuilder( HttpConfiguration configuration )
         protected ApiVersioningOptions Options => Configuration.GetApiVersioningOptions();
 
         /// <summary>
-        /// Builds and returns the sequence of EDM models based on the define model configurations.
+        /// Gets the API versions for all known OData routes.
         /// </summary>
-        /// <returns>A <see cref="IEnumerable{T}">sequence</see> of <see cref="IEdmModel">EDM models</see>.</returns>
-        [SuppressMessage( "Microsoft.Design", "CA1024:UsePropertiesWhereAppropriate", Justification = "Matches plural form of ODataModelBuilder.GetEdmModel(). A property would also not be appropriate." )]
-        public virtual IEnumerable<IEdmModel> GetEdmModels()
+        /// <returns>The <see cref="IReadOnlyList{T}">sequence</see> of <see cref="ApiVersion">API versions</see>
+        /// for all known OData routes.</returns>
+        protected virtual IReadOnlyList<ApiVersion> GetApiVersions()
         {
-            Contract.Ensures( Contract.Result<IEnumerable<IEdmModel>>() != null );
+            Contract.Ensures( Contract.Result<IReadOnlyList<ApiVersion>>() != null );
 
-            var configurations = GetMergedConfigurations();
-            var models = new List<IEdmModel>();
             var services = Configuration.Services;
             var assembliesResolver = services.GetAssembliesResolver();
             var typeResolver = services.GetHttpControllerTypeResolver();
@@ -69,23 +66,31 @@ public virtual IEnumerable<IEdmModel> GetEdmModels()
                 conventions.ApplyTo( descriptor );
 
                 var model = descriptor.GetApiVersionModel();
+                var versions = model.SupportedApiVersions;
 
-                foreach ( var apiVersion in model.SupportedApiVersions )
+                for ( var i = 0; i < versions.Count; i++ )
                 {
-                    supported.Add( apiVersion );
+                    supported.Add( versions[i] );
                 }
 
-                foreach ( var apiVersion in model.DeprecatedApiVersions )
+                versions = model.DeprecatedApiVersions;
+
+                for ( var i = 0; i < versions.Count; i++ )
                 {
-                    deprecated.Add( apiVersion );
+                    deprecated.Add( versions[i] );
                 }
             }
 
             deprecated.ExceptWith( supported );
-            BuildModelPerApiVersion( supported.Union( deprecated ), configurations, models );
+
+            if ( supported.Count == 0 && deprecated.Count == 0 )
+            {
+                supported.Add( Options.DefaultApiVersion );
+            }
+
             ConfigureMetadataController( supported, deprecated );
 
-            return models;
+            return supported.Union( deprecated ).ToArray();
         }
 
         /// <summary>

src/Microsoft.AspNetCore.OData.Versioning/AspNet.OData/Builder/VersionedODataModelBuilder.cs

@@ -6,11 +6,9 @@
     using Microsoft.AspNetCore.Mvc.Infrastructure;
     using Microsoft.AspNetCore.Mvc.Versioning;
     using Microsoft.Extensions.Options;
-    using Microsoft.OData.Edm;
     using System;
     using System.Collections.Generic;
     using System.Diagnostics.Contracts;
-    using System.Linq;
     using static System.Linq.Enumerable;
 
     /// <content>
@@ -66,38 +64,24 @@ public VersionedODataModelBuilder(
         /// <value>The associated <see cref="ApiVersioningOptions">API versioning options</see>.</value>
         protected ApiVersioningOptions Options => options.Value;
 
-        /// <summary>
-        /// Builds and returns the sequence of EDM models based on the define model configurations.
-        /// </summary>
-        /// <returns>A <see cref="IEnumerable{T}">sequence</see> of <see cref="IEdmModel">EDM models</see>.</returns>
-        public virtual IEnumerable<IEdmModel> GetEdmModels()
-        {
-            Contract.Ensures( Contract.Result<IEnumerable<IEdmModel>>() != null );
-
-            var apiVersions = GetApiVersions();
-            var configurations = GetMergedConfigurations();
-            var models = new List<IEdmModel>();
-
-            BuildModelPerApiVersion( apiVersions, configurations, models );
-
-            return models;
-        }
-
         /// <summary>
         /// Gets the API versions for all known OData routes.
         /// </summary>
-        /// <returns>The <see cref="IEnumerable{T}">sequence</see> of <see cref="ApiVersion">API versions</see>
+        /// <returns>The <see cref="IReadOnlyList{T}">sequence</see> of <see cref="ApiVersion">API versions</see>
         /// for all known OData routes.</returns>
-        protected virtual IEnumerable<ApiVersion> GetApiVersions()
+        protected virtual IReadOnlyList<ApiVersion> GetApiVersions()
         {
-            Contract.Ensures( Contract.Result<IEnumerable<ApiVersion>>() != null );
+            Contract.Ensures( Contract.Result<IReadOnlyList<ApiVersion>>() != null );
 
-            var actions = ActionDescriptorCollectionProvider.ActionDescriptors.Items.OfType<ControllerActionDescriptor>();
-            var implemented = new HashSet<ApiVersion>();
+            var items = ActionDescriptorCollectionProvider.ActionDescriptors.Items;
+            var supported = new HashSet<ApiVersion>();
+            var deprecated = new HashSet<ApiVersion>();
 
-            foreach ( var action in actions )
+            for ( var i = 0; i < items.Count; i++ )
             {
-                if ( !action.ControllerTypeInfo.IsODataController() )
+                var item = items[i];
+
+                if ( !( item is ControllerActionDescriptor action ) || !action.ControllerTypeInfo.IsODataController() )
                 {
                     continue;
                 }
@@ -109,25 +93,29 @@ protected virtual IEnumerable<ApiVersion> GetApiVersions()
                     continue;
                 }
 
-                foreach ( var apiVersion in model.ImplementedApiVersions )
+                var versions = model.SupportedApiVersions;
+
+                for ( var j = 0; j < versions.Count; j++ )
                 {
-                    implemented.Add( apiVersion );
+                    supported.Add( versions[j] );
                 }
-            }
 
-            if ( implemented.Count == 0 )
-            {
-                implemented.Add( Options.DefaultApiVersion );
+                versions = model.DeprecatedApiVersions;
+
+                for ( var j = 0; j < versions.Count; j++ )
+                {
+                    deprecated.Add( versions[j] );
+                }
             }
 
-            var apiVersions = implemented.ToArray();
+            deprecated.ExceptWith( supported );
 
-            if ( apiVersions.Length > 1 )
+            if ( supported.Count == 0 && deprecated.Count == 0 )
             {
-                Array.Sort( apiVersions );
+                supported.Add( Options.DefaultApiVersion );
             }
 
-            return apiVersions;
+            return supported.Union( deprecated ).ToArray();
         }
     }
 }

test/Microsoft.AspNetCore.OData.Versioning.ApiExplorer.Tests/AspNetCore.Mvc.ApiExplorer/ODataApiDescriptionProviderTest.cs

@@ -7,6 +7,7 @@
     using Microsoft.AspNetCore.Hosting;
     using Microsoft.AspNetCore.TestHost;
     using Microsoft.Extensions.DependencyInjection;
+    using System.Linq;
     using Xunit;
 
     public class ODataApiDescriptionProviderTest
@@ -33,10 +34,14 @@ public void odata_api_explorer_should_group_and_order_descriptions_on_providers_
             var serviceProvider = server.Host.Services;
 
             // act
-            var groups = serviceProvider.GetRequiredService<IApiDescriptionGroupCollectionProvider>().ApiDescriptionGroups.Items;
+            var groups = serviceProvider.GetRequiredService<IApiDescriptionGroupCollectionProvider>()
+                                        .ApiDescriptionGroups
+                                        .Items
+                                        .OrderBy( i => i.GroupName )
+                                        .ToArray();
 
             // assert
-            groups.Count.Should().Be( 4 );
+            groups.Length.Should().Be( 4 );
             AssertVersion0_9( groups[0] );
             AssertVersion1( groups[1] );
             AssertVersion2( groups[2] );