improve perf of DisplayAttribute detection

src/Humanizer.Tests/Humanizer.Tests.csproj

@@ -12,9 +12,7 @@
     <PackageReference Include="Verify.DiffPlex" Version="2.3.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.9.0" />
     <ProjectReference Include="..\Humanizer\Humanizer.csproj" />
-  </ItemGroup>
-  <ItemGroup Condition="'$(TargetFramework)' == 'net48' ">
-    <Reference Include="System.ComponentModel.DataAnnotations" />
+    <Reference Include="System.ComponentModel.DataAnnotations"  Condition="'$(TargetFramework)' == 'net48' "/>
   </ItemGroup>
   <ItemGroup>
     <Compile Include="..\Humanizer.Tests.Shared\**\*.cs">

src/Humanizer/EnumHumanizeExtensions.cs

@@ -1,5 +1,6 @@
 using System.Reflection;
 using Humanizer.Configuration;
+using System.ComponentModel.DataAnnotations;
 
 namespace Humanizer
 {
@@ -8,41 +9,34 @@ namespace Humanizer
     /// </summary>
     public static class EnumHumanizeExtensions
     {
-        private const string DisplayAttributeTypeName = "System.ComponentModel.DataAnnotations.DisplayAttribute";
-        private const string DisplayAttributeGetDescriptionMethodName = "GetDescription";
-        private const string DisplayAttributeGetNameMethodName = "GetName";
-
-        private static readonly Func<PropertyInfo, bool> StringTypedProperty = p => p.PropertyType == typeof(string);
-
         /// <summary>
         /// Turns an enum member into a human readable string; e.g. AnonymousUser -> Anonymous user. It also honors DescriptionAttribute data annotation
         /// </summary>
         /// <param name="input">The enum member to be humanized</param>
         public static string Humanize(this Enum input)
         {
-            var enumType = input.GetType();
-            var enumTypeInfo = enumType.GetTypeInfo();
+            var type = input.GetType();
 
-            if (IsBitFieldEnum(enumTypeInfo) && !Enum.IsDefined(enumType, input))
+            if (IsBitFieldEnum(type) && !Enum.IsDefined(type, input))
             {
-                return Enum.GetValues(enumType)
+                return Enum.GetValues(type)
                            .Cast<Enum>()
-                           .Where(e => e.CompareTo(Convert.ChangeType(Enum.ToObject(enumType, 0), enumType)) != 0)
+                           .Where(e => e.CompareTo(Convert.ChangeType(Enum.ToObject(type, 0), type)) != 0)
                            .Where(input.HasFlag)
                            .Select(e => e.Humanize())
                            .Humanize();
             }
 
             var caseName = input.ToString();
-            var memInfo = enumTypeInfo.GetDeclaredField(caseName);
+            var member = type.GetTypeInfo().GetDeclaredField(caseName);
 
-            if (memInfo != null)
+            if (member != null)
             {
-                var customDescription = GetCustomDescription(memInfo);
+                var description = GetCustomDescription(member);
 
-                if (customDescription != null)
+                if (description != null)
                 {
-                    return customDescription;
+                    return description;
                 }
             }
 
@@ -53,45 +47,31 @@ public static string Humanize(this Enum input)
         /// Checks whether the given enum is to be used as a bit field type.
         /// </summary>
         /// <returns>True if the given enum is a bit field enum, false otherwise.</returns>
-        private static bool IsBitFieldEnum(TypeInfo typeInfo)
+        private static bool IsBitFieldEnum(Type type)
         {
-            return typeInfo.GetCustomAttribute(typeof(FlagsAttribute)) != null;
+            return type.GetCustomAttribute(typeof(FlagsAttribute)) != null;
         }
 
-        // I had to add this method because PCL doesn't have DescriptionAttribute & I didn't want two versions of the code & thus the reflection
         private static string GetCustomDescription(MemberInfo memberInfo)
         {
-            var attrs = memberInfo.GetCustomAttributes(true);
-
-            foreach (var attr in attrs)
+            var displayAttribute = memberInfo.GetCustomAttribute<DisplayAttribute>();
+            if (displayAttribute != null)
             {
-                var attrType = attr.GetType();
-                if (attrType.FullName == DisplayAttributeTypeName)
+                var description = displayAttribute.GetDescription();
+                if (description != null)
                 {
-                    var methodGetDescription = attrType.GetRuntimeMethod(DisplayAttributeGetDescriptionMethodName, new Type[0]);
-                    if (methodGetDescription != null)
-                    {
-                        var executedMethod = methodGetDescription.Invoke(attr, new object[0]);
-                        if (executedMethod != null)
-                        {
-                            return executedMethod.ToString();
-                        }
-                    }
-                    var methodGetName = attrType.GetRuntimeMethod(DisplayAttributeGetNameMethodName, new Type[0]);
-                    if (methodGetName != null)
-                    {
-                        var executedMethod = methodGetName.Invoke(attr, new object[0]);
-                        if (executedMethod != null)
-                        {
-                            return executedMethod.ToString();
-                        }
-                    }
-                    return null;
+                    return description;
                 }
 
+                return displayAttribute.GetName();
+            }
+
+            foreach (var attr in memberInfo.GetCustomAttributes())
+            {
+                var attrType = attr.GetType();
                 var descriptionProperty =
                     attrType.GetRuntimeProperties()
-                        .Where(StringTypedProperty)
+                        .Where(p => p.PropertyType == typeof(string))
                         .FirstOrDefault(Configurator.EnumDescriptionPropertyLocator);
                 if (descriptionProperty != null)
                 {

src/Humanizer/Humanizer.csproj

@@ -16,6 +16,7 @@
   </PropertyGroup>  
   <ItemGroup>
     <Using Remove="System.Net.Http" />
+    <PackageReference Include="System.ComponentModel.Annotations" Version="4.3.0" Condition="'$(TargetFramework)' == 'netstandard2.0' " />
     <None Update="FluentDate\InDate.Months.tt">
       <LastGenOutput>InDate.Months.cs</LastGenOutput>
       <Generator>TextTemplatingFileGenerator</Generator>
@@ -46,5 +47,5 @@
   </ItemGroup>  
   <ItemGroup>
     <Service Include="{508349b6-6b84-4df5-91f0-309beebad82d}" />
-  </ItemGroup>  
+  </ItemGroup>
 </Project>