Imported Upstream version 3.6.0

Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14

external/aspnetwebstack/src/System.Web.Http/Validation/ModelValidationRequiredMemberSelector.cs

@@ -0,0 +1,59 @@
+// Copyright (c) Microsoft Corporation. All rights reserved. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Http.Formatting;
+using System.Reflection;
+using System.Web.Http.Metadata;
+
+namespace System.Web.Http.Validation
+{
+    /// <summary>
+    /// This <see cref="IRequiredMemberSelector"/> selects required members by checking for any 
+    /// required ModelValidators associated with the member. This is the default implementation used by
+    /// <see cref="HttpConfiguration"/>.
+    /// </summary>
+    public sealed class ModelValidationRequiredMemberSelector : IRequiredMemberSelector
+    {
+        private readonly ModelMetadataProvider _metadataProvider;
+        private readonly List<ModelValidatorProvider> _validatorProviders;
+
+        public ModelValidationRequiredMemberSelector(ModelMetadataProvider metadataProvider, IEnumerable<ModelValidatorProvider> validatorProviders)
+        {
+            if (metadataProvider == null)
+            {
+                throw Error.ArgumentNull("metadataProvider");
+            }
+            if (validatorProviders == null)
+            {
+                throw Error.ArgumentNull("validatorProviders");
+            }
+
+            _metadataProvider = metadataProvider;
+            _validatorProviders = validatorProviders.ToList();
+        }
+
+        public bool IsRequiredMember(MemberInfo member)
+        {
+            if (member == null)
+            {
+                throw Error.ArgumentNull("member");
+            }
+
+            // Optimization : avoid computing validators if there are no validator providers
+            if (_validatorProviders == null || !_validatorProviders.Any())
+            {
+                return false;
+            }
+
+            if (!(member is PropertyInfo))
+            {
+                return false;
+            }
+
+            ModelMetadata metadata = _metadataProvider.GetMetadataForProperty(() => null, member.DeclaringType, member.Name);
+            IEnumerable<ModelValidator> validators = metadata.GetValidators(_validatorProviders);
+            return validators.Any(validator => validator.IsRequired);
+        }
+    }
+}