From 1f67bb99ebd5a4fc55f3ebb1dfcee9bf67819925 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Habinshuti?= <haby_habbes@live.com>
Date: Thu, 30 Nov 2023 15:03:35 +0300
Subject: [PATCH] Slight performance improvement for
 `IEdmNavigationSource.EntityType()` (#2808)

* Simplify EntityType() method

* Optimize Type property in CsdlSemanticsEntitySet and Singleton
---
 .../Csdl/Semantics/CsdlSemanticsEntitySet.cs  | 12 +++++++-
 .../Csdl/Semantics/CsdlSemanticsSingleton.cs  | 12 +++++++-
 .../ExtensionMethods/ExtensionMethods.cs      | 29 +------------------
 3 files changed, 23 insertions(+), 30 deletions(-)

diff --git a/src/Microsoft.OData.Edm/Csdl/Semantics/CsdlSemanticsEntitySet.cs b/src/Microsoft.OData.Edm/Csdl/Semantics/CsdlSemanticsEntitySet.cs
index a5e0f77639..f9c66e98c9 100644
--- a/src/Microsoft.OData.Edm/Csdl/Semantics/CsdlSemanticsEntitySet.cs
+++ b/src/Microsoft.OData.Edm/Csdl/Semantics/CsdlSemanticsEntitySet.cs
@@ -19,9 +19,19 @@ public CsdlSemanticsEntitySet(CsdlSemanticsEntityContainer container, CsdlEntity
         {
         }
 
+        private IEdmType type;
+
         public override IEdmType Type
         {
-            get { return new EdmCollectionType(new EdmEntityTypeReference(this.typeCache.GetValue(this, ComputeElementTypeFunc, null), false)); }
+            get 
+            {
+                if (type == null)
+                {
+                    type = new EdmCollectionType(new EdmEntityTypeReference(this.typeCache.GetValue(this, ComputeElementTypeFunc, null), false));
+                }
+
+                return type;
+            }
         }
 
         public override EdmContainerElementKind ContainerElementKind
diff --git a/src/Microsoft.OData.Edm/Csdl/Semantics/CsdlSemanticsSingleton.cs b/src/Microsoft.OData.Edm/Csdl/Semantics/CsdlSemanticsSingleton.cs
index 04e8dfd0bc..bdb7589fbb 100644
--- a/src/Microsoft.OData.Edm/Csdl/Semantics/CsdlSemanticsSingleton.cs
+++ b/src/Microsoft.OData.Edm/Csdl/Semantics/CsdlSemanticsSingleton.cs
@@ -19,9 +19,19 @@ public CsdlSemanticsSingleton(CsdlSemanticsEntityContainer container, CsdlSingle
         {
         }
 
+        private IEdmType type;
+
         public override IEdmType Type
         {
-            get { return this.typeCache.GetValue(this, ComputeElementTypeFunc, null); }
+            get
+            { 
+                if (type == null)
+                {
+                    type = this.typeCache.GetValue(this, ComputeElementTypeFunc, null);
+                }
+
+                return type;
+            }
         }
 
         public override EdmContainerElementKind ContainerElementKind
diff --git a/src/Microsoft.OData.Edm/ExtensionMethods/ExtensionMethods.cs b/src/Microsoft.OData.Edm/ExtensionMethods/ExtensionMethods.cs
index a69c3bf04e..8c5cb2ca96 100644
--- a/src/Microsoft.OData.Edm/ExtensionMethods/ExtensionMethods.cs
+++ b/src/Microsoft.OData.Edm/ExtensionMethods/ExtensionMethods.cs
@@ -2822,34 +2822,7 @@ public static string FullNavigationSourceName(this IEdmNavigationSource navigati
         /// <returns>The entity type of the navigation source.</returns>
         public static IEdmEntityType EntityType(this IEdmNavigationSource navigationSource)
         {
-            var entitySetBase = navigationSource as IEdmEntitySetBase;
-            if (entitySetBase != null)
-            {
-                IEdmCollectionType collectionType = entitySetBase.Type as IEdmCollectionType;
-
-                if (collectionType != null)
-                {
-                    return collectionType.ElementType.Definition as IEdmEntityType;
-                }
-
-                var unknownEntitySet = entitySetBase as IEdmUnknownEntitySet;
-                if (unknownEntitySet != null)
-                {
-                    // Handle missing navigation target for nullable
-                    // singleton navigation property.
-                    return unknownEntitySet.Type as IEdmEntityType;
-                }
-
-                return null;
-            }
-
-            var singleton = navigationSource as IEdmSingleton;
-            if (singleton != null)
-            {
-                return singleton.Type as IEdmEntityType;
-            }
-
-            return null;
+            return navigationSource?.Type.AsElementType() as IEdmEntityType;
         }
 
         #endregion