Removed use of LINQ and added some optimizations in ValidationVisitor

src/Microsoft.AspNet.Mvc.Abstractions/ModelBinding/Validation/IModelValidator.cs

@@ -10,12 +10,6 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Validation
     /// </summary>
     public interface IModelValidator
     {
-        /// <summary>
-        /// Gets a value indicating whether or not this validator validates that a required value
-        /// has been provided for the model.
-        /// </summary>
-        bool IsRequired { get; }
-
         /// <summary>
         /// Validates the model value.
         /// </summary>

src/Microsoft.AspNet.Mvc.Abstractions/ModelBinding/Validation/ModelValiatorProviderContext.cs

@@ -22,7 +22,7 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Validation
         /// <summary>
         /// Gets the <see cref="ModelBinding.ModelMetadata"/>.
         /// </summary>
-        public ModelMetadata ModelMetadata { get; }
+        public ModelMetadata ModelMetadata { get; set; }
 
         /// <summary>
         /// Gets the validator metadata.

src/Microsoft.AspNet.Mvc.Core/ModelBinding/Validation/ValidationVisitor.cs

@@ -3,7 +3,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using System.Runtime.CompilerServices;
 
 namespace Microsoft.AspNet.Mvc.ModelBinding.Validation
@@ -23,6 +22,7 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Validation
         private string _key;
         private object _model;
         private ModelMetadata _metadata;
+        private ModelValidatorProviderContext _context;
         private IValidationStrategy _strategy;
 
         private HashSet<object> _currentPath;
@@ -94,7 +94,7 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Validation
             var state = _modelState.GetValidationState(_key);
             if (state == ModelValidationState.Unvalidated)
             {
-                var validators = GetValidators(_metadata);
+                var validators = GetValidators();
 
                 var count = validators.Count;
                 if (count > 0)
@@ -255,11 +255,23 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Validation
             return isValid;
         }
 
-        private IList<IModelValidator> GetValidators(ModelMetadata metadata)
+        private IList<IModelValidator> GetValidators()
         {
-            var context = new ModelValidatorProviderContext(metadata);
+            if (_context == null)
-            _validatorProvider.GetValidators(context);
+            {
-            return context.Validators.OrderBy(v => v, ValidatorOrderComparer.Instance).ToList();
+                _context = new ModelValidatorProviderContext(_metadata);
+            }
+            else
+            {
+                // Reusing the context so we don't allocate a new context and list
+                // for every property that gets validated.
+                _context.ModelMetadata = _metadata;
+                _context.Validators.Clear();
+            }
+
+            _validatorProvider.GetValidators(_context);
+
+            return _context.Validators;
         }
 
         private void SuppressValidation(string key)
@@ -348,19 +360,5 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Validation
                 _visitor._currentPath.Remove(_newModel);
             }
         }
-
-        // Sorts validators based on whether or not they are 'required'. We want to run
-        // 'required' validators first so that we get the best possible error message.
-        private class ValidatorOrderComparer : IComparer<IModelValidator>
-        {
-            public static readonly ValidatorOrderComparer Instance = new ValidatorOrderComparer();
-
-            public int Compare(IModelValidator x, IModelValidator y)
-            {
-                var xScore = x.IsRequired ? 0 : 1;
-                var yScore = y.IsRequired ? 0 : 1;
-                return xScore.CompareTo(yScore);
-            }
-        }
     }
 }

src/Microsoft.AspNet.Mvc.DataAnnotations/DataAnnotationsModelValidator.cs

@@ -26,11 +26,6 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Validation
 
         public ValidationAttribute Attribute { get; }
 
-        public bool IsRequired
-        {
-            get { return Attribute is RequiredAttribute; }
-        }
-
         public IEnumerable<ModelValidationResult> Validate(ModelValidationContext validationContext)
         {
             var metadata = validationContext.Metadata;

src/Microsoft.AspNet.Mvc.DataAnnotations/DataAnnotationsModelValidatorProvider.cs

@@ -1,9 +1,7 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System;
 using System.ComponentModel.DataAnnotations;
-using System.Linq;
 using System.Reflection;
 using Microsoft.Extensions.Localization;
 using Microsoft.Extensions.OptionsModel;
@@ -43,9 +41,26 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Validation
                     _stringLocalizerFactory);
             }
 
-            foreach (var attribute in context.ValidatorMetadata.OfType<ValidationAttribute>())
+            for (var i = 0; i < context.ValidatorMetadata.Count; i++)
             {
-                context.Validators.Add(new DataAnnotationsModelValidator(attribute, stringLocalizer));
+                var attribute = context.ValidatorMetadata[i] as ValidationAttribute;
+                if (attribute == null)
+                {
+                    continue;
+                }
+
+                var validator = new DataAnnotationsModelValidator(attribute, stringLocalizer);
+
+                // Inserts validators based on whether or not they are 'required'. We want to run
+                // 'required' validators first so that we get the best possible error message.
+                if (attribute is RequiredAttribute)
+                {
+                    context.Validators.Insert(0, validator);
+                }
+                else
+                {
+                    context.Validators.Add(validator);
+                }
             }
 
             // Produce a validator if the type supports IValidatableObject

src/Microsoft.AspNet.Mvc.DataAnnotations/ValidatableObjectAdapter.cs

@@ -11,11 +11,6 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Validation
 {
     public class ValidatableObjectAdapter : IModelValidator
     {
-        public bool IsRequired
-        {
-            get { return false; }
-        }
-
         public IEnumerable<ModelValidationResult> Validate(ModelValidationContext context)
         {
             var model = context.Model;

test/Microsoft.AspNet.Mvc.Core.Test/ModelBinding/Metadata/DefaultValidationMetadataTest.cs

@@ -70,14 +70,6 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Metadata
 
         private class TestModelValidationAttribute : Attribute, IModelValidator
         {
-            public bool IsRequired
-            {
-                get
-                {
-                    throw new NotImplementedException();
-                }
-            }
-
             public IEnumerable<ModelValidationResult> Validate(ModelValidationContext context)
             {
                 throw new NotImplementedException();
@@ -94,14 +86,6 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Metadata
 
         private class TestValidationAttribute : Attribute, IModelValidator, IClientModelValidator
         {
-            public bool IsRequired
-            {
-                get
-                {
-                    throw new NotImplementedException();
-                }
-            }
-
             public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ClientModelValidationContext context)
             {
                 throw new NotImplementedException();

test/Microsoft.AspNet.Mvc.Core.Test/ModelBinding/Validation/DefaultModelValidatorProviderTest.cs

@@ -171,14 +171,6 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Validation
         {
             public string Tag { get; set; }
 
-            public bool IsRequired
-            {
-                get
-                {
-                    throw new NotImplementedException();
-                }
-            }
-
             public IEnumerable<ModelValidationResult> Validate(ModelValidationContext context)
             {
                 throw new NotImplementedException();

test/Microsoft.AspNet.Mvc.DataAnnotations.Test/DataAnnotationsModelValidatorProviderTest.cs

@@ -38,6 +38,27 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Validation
         }
 #endif
 
+        [Fact]
+        public void GetValidators_InsertsRequiredValidatorsFirst()
+        {
+            var provider = new DataAnnotationsModelValidatorProvider(
+                new TestOptionsManager<MvcDataAnnotationsLocalizationOptions>(),
+                stringLocalizerFactory: null);
+            var metadata = _metadataProvider.GetMetadataForProperty(
+                typeof(ClassWithProperty),
+                "PropertyWithMultipleValidationAttributes");
+
+            var providerContext = new ModelValidatorProviderContext(metadata);
+
+            // Act
+            provider.GetValidators(providerContext);
+
+            // Assert
+            Assert.Equal(4, providerContext.Validators.Count);
+            Assert.IsAssignableFrom<RequiredAttribute>(((DataAnnotationsModelValidator)providerContext.Validators[0]).Attribute);
+            Assert.IsAssignableFrom<RequiredAttribute>(((DataAnnotationsModelValidator)providerContext.Validators[1]).Attribute);
+        }
+
         [Fact]
         public void UnknownValidationAttributeGetsDefaultAdapter()
         {
@@ -130,5 +151,30 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Validation
 
             public int WithoutAttribute { get; set; }
         }
+
+        private class ClassWithProperty
+        {
+            [CustomNonRequiredAttribute1]
+            [CustomNonRequiredAttribute2]
+            [CustomRequiredAttribute1]
+            [CustomRequiredAttribute2]
+            public string PropertyWithMultipleValidationAttributes { get; set; }
+        }
+
+        public class CustomRequiredAttribute1 : RequiredAttribute
+        {
+        }
+
+        public class CustomRequiredAttribute2 : RequiredAttribute
+        {
+        }
+
+        public class CustomNonRequiredAttribute1 : ValidationAttribute
+        {
+        }
+
+        public class CustomNonRequiredAttribute2 : ValidationAttribute
+        {
+        }
     }
 }

test/Microsoft.AspNet.Mvc.DataAnnotations.Test/DataAnnotationsModelValidatorTest.cs

@@ -294,17 +294,6 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Validation
         }
 #endif
 
-        [Fact]
-        public void IsRequiredTests()
-        {
-            // Arrange & Act & Assert
-            Assert.False(new DataAnnotationsModelValidator(new RangeAttribute(10, 20), stringLocalizer: null)
-                .IsRequired);
-            Assert.True(new DataAnnotationsModelValidator(new RequiredAttribute(), stringLocalizer: null).IsRequired);
-            Assert.True(new DataAnnotationsModelValidator(new DerivedRequiredAttribute(), stringLocalizer: null)
-                .IsRequired);
-        }
-
         private class DerivedRequiredAttribute : RequiredAttribute
         {
         }

test/Microsoft.AspNet.Mvc.DataAnnotations.Test/DefaultModelClientValidatorProviderTest.cs

@@ -218,14 +218,6 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Validation
         {
             public string Tag { get; set; }
 
-            public bool IsRequired
-            {
-                get
-                {
-                    throw new NotImplementedException();
-                }
-            }
-
             public IEnumerable<ModelValidationResult> Validate(ModelValidationContext context)
             {
                 throw new NotImplementedException();