Use Lazy<T> for GeometryServiceProvider.Instance.

On platforms that support it, anyway.
NetTopologySuite · Apr 13, 2018 · e405106 · e405106
1 parent 8635a94
commit e405106
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Showing 2 changed files with 18 additions and 1 deletion.
diff --git a/src/GeoAPI/GeoAPI.csproj b/src/GeoAPI/GeoAPI.csproj
@@ -63,6 +63,7 @@
     <DefineConstants>$(DefineConstants);FEATURE_DEFAULT_PARAMETERS</DefineConstants>
     <DefineConstants>$(DefineConstants);FEATURE_INTERFACE_VARIANCE</DefineConstants>
     <DefineConstants>$(DefineConstants);HAS_SYSTEM_DOUBLE_TRYPARSE</DefineConstants>
+    <DefineConstants>$(DefineConstants);HAS_SYSTEM_LAZY_T</DefineConstants>
     <DefineConstants>$(DefineConstants);HAS_SYSTEM_STRING_TOUPPERINVARIANT</DefineConstants>
   </PropertyGroup>
 
@@ -82,6 +83,7 @@
     <DefineConstants>$(DefineConstants);FEATURE_DEFAULT_PARAMETERS</DefineConstants>
     <DefineConstants>$(DefineConstants);FEATURE_INTERFACE_VARIANCE</DefineConstants>
     <DefineConstants>$(DefineConstants);HAS_SYSTEM_DOUBLE_TRYPARSE</DefineConstants>
+    <DefineConstants>$(DefineConstants);HAS_SYSTEM_LAZY_T</DefineConstants>
     <DefineConstants>$(DefineConstants);HAS_SYSTEM_STRING_TOUPPERINVARIANT</DefineConstants>
   </PropertyGroup>
 
@@ -110,6 +112,10 @@
     <DefineConstants>$(DefineConstants);HAS_SYSTEM_STRING_TOUPPER_CULTUREINFO</DefineConstants>
   </PropertyGroup>
 
+  <PropertyGroup Condition=" '$(TargetFramework)' == 'net40' Or '$(TargetFramework)' == 'net40-client' Or '$(TargetFramework)' == 'net403' Or '$(TargetFramework)' == 'net403-client' Or '$(TargetFramework)' == 'net45' ">
+    <DefineConstants>$(DefineConstants);HAS_SYSTEM_LAZY_T</DefineConstants>
+  </PropertyGroup>
+
   <PropertyGroup Condition=" '$(TargetFramework)' == 'netstandard1.0' ">
     <DisableImplicitFrameworkReferences>true</DisableImplicitFrameworkReferences>
   </PropertyGroup>
@@ -119,6 +125,7 @@
     <DefineConstants>$(DefineConstants);FEATURE_INTERFACE_VARIANCE</DefineConstants>
 
     <DefineConstants>$(DefineConstants);HAS_SYSTEM_DOUBLE_TRYPARSE</DefineConstants>
+    <DefineConstants>$(DefineConstants);HAS_SYSTEM_LAZY_T</DefineConstants>
     <DefineConstants>$(DefineConstants);HAS_SYSTEM_STRING_TOUPPERINVARIANT</DefineConstants>
   </PropertyGroup>
 

diff --git a/src/GeoAPI/GeometryServiceProvider.cs b/src/GeoAPI/GeometryServiceProvider.cs
@@ -9,14 +9,23 @@ namespace GeoAPI
     /// </summary>
     public static class GeometryServiceProvider
     {
-        private static IGeometryServices _instance;
+#if HAS_SYSTEM_LAZY_T
+        private static readonly Lazy<IGeometryServices> ReflectedInstance = new Lazy<IGeometryServices>(ReflectInstance);
+#else
         private static readonly object LockObject = new object();
+#endif
+
+        private static volatile IGeometryServices _instance;
 
         /// <summary>
         /// Gets or sets the <see cref="IGeometryServices"/> instance.
         /// </summary>
         public static IGeometryServices Instance
         {
+#if HAS_SYSTEM_LAZY_T
+            get => _instance ?? ReflectedInstance.Value;
+            set => _instance = value ?? throw new ArgumentNullException(nameof(value));
+#else
             get
             {
                 lock (LockObject)
@@ -35,6 +44,7 @@ public static IGeometryServices Instance
                     _instance = value;
                 }
             }
+#endif
         }
 
 #if HAS_SYSTEM_REFLECTION_ASSEMBLY_GETEXPORTEDTYPES