Revert the related fix in 5.5.0

Author: LianwMS

OData/src/System.Web.OData/Extensions/HttpRequestMessageProperties.cs

@@ -33,7 +33,6 @@ public class HttpRequestMessageProperties
         private const string RoutingConventionsKey = "System.Web.OData.RoutingConventions";
         private const string SelectExpandClauseKey = "System.Web.OData.SelectExpandClause";
         private const string TotalCountKey = "System.Web.OData.TotalCount";
-        private const string TotalCountFuncKey = "System.Web.OData.TotalCountFunc";
 
         internal const string ODataServiceVersionHeader = "OData-Version";
         internal const string ODataMaxServiceVersionHeader = "OData-MaxVersion";
@@ -48,24 +47,6 @@ internal HttpRequestMessageProperties(HttpRequestMessage request)
             _request = request;
         }
 
-        internal Func<long> TotalCountFunc
-        {
-            get
-            {
-                object totalCountFunc;
-                if (_request.Properties.TryGetValue(TotalCountFuncKey, out totalCountFunc))
-                {
-                    return (Func<long>)totalCountFunc;
-                }
-
-                return null;
-            }
-            set
-            {
-                _request.Properties[TotalCountFuncKey] = value;
-            }
-        }
-
         /// <summary>
         /// Gets or sets the EDM model associated with the request.
         /// </summary>
@@ -165,11 +146,6 @@ public long? TotalCount
                     return (long)totalCount;
                 }
 
-                if (this.TotalCountFunc != null)
-                {
-                    return this.TotalCountFunc();
-                }
-
                 return null;
             }
             set

OData/src/System.Web.OData/OData/ExpressionHelpers.cs

@@ -13,11 +13,10 @@ namespace System.Web.OData
 {
     internal static class ExpressionHelpers
     {
-        public static Func<long> Count(IQueryable query, Type type)
+        public static long Count(IQueryable query, Type type)
         {
             MethodInfo countMethod = ExpressionHelperMethods.QueryableCountGeneric.MakeGenericMethod(type);
-            Expression<Func<long>> func = Expression.Lambda<Func<long>>(Expression.Call(null, countMethod, query.Expression));
-            return func.Compile();
+            return (long)countMethod.Invoke(null, new object[] { query });
         }
 
         public static IQueryable Skip(IQueryable query, int count, Type type, bool parameterize)

OData/src/System.Web.OData/OData/Query/CountQueryOption.cs

@@ -135,28 +135,6 @@ public void Validate(ODataValidationSettings validationSettings)
                 throw Error.NotSupported(SRResources.ApplyToOnUntypedQueryOption, "GetEntityCount");
             }
 
-            if (Value)
-            {
-                return ExpressionHelpers.Count(query, Context.ElementClrType)();
-            }
-            else
-            {
-                return null;
-            }
-        }
-
-        /// <summary>
-        /// Gets the Func of entities number that satisfy the given query if the response should include a count query option, or <c>null</c> otherwise.
-        /// </summary>
-        /// <param name="query">The query to compute the count for.</param>
-        /// <returns>The the Func of entities number that satisfy the specified query if the response should include a count query option, or <c>null</c> otherwise.</returns>
-        internal Func<long> GetEntityCountFunc(IQueryable query)
-        {
-            if (Context.ElementClrType == null)
-            {
-                throw Error.NotSupported(SRResources.ApplyToOnUntypedQueryOption, "GetEntityCount");
-            }
-
             if (Value)
             {
                 return ExpressionHelpers.Count(query, Context.ElementClrType);

OData/src/System.Web.OData/OData/Query/ODataQueryOptions.cs

@@ -261,12 +261,12 @@ public virtual IQueryable ApplyTo(IQueryable query, ODataQuerySettings querySett
 
             if (Count != null)
             {
-                if (Request.ODataProperties().TotalCountFunc == null)
+                if (Request.ODataProperties().TotalCount == null)
                 {
-                    Func<long> countFunc = Count.GetEntityCountFunc(result);
-                    if (countFunc != null)
+                    long? count = Count.GetEntityCount(result);
+                    if (count.HasValue)
                     {
-                        Request.ODataProperties().TotalCountFunc = countFunc;
+                        Request.ODataProperties().TotalCount = count.Value;
                     }
                 }
 

OData/test/System.Web.OData.Test/OData/Query/CountQueryOptionTest.cs

@@ -133,26 +133,6 @@ public void GetEntityCount_ReturnsNull_IfValueIsFalse()
             Assert.Null(countOption.GetEntityCount(_customers));
         }
 
-        [Fact]
-        public void GetEntityCountFunc_ReturnsFunc_IfValueIsTrue()
-        {
-            // Arrange
-            var countOption = new CountQueryOption("true", _context);
-
-            // Act & Assert
-            Assert.Equal(3, countOption.GetEntityCountFunc(_customers)());
-        }
-
-        [Fact]
-        public void GetEntityCountFunc_ReturnsNull_IfValueIsFalse()
-        {
-            // Arrange
-            var countOption = new CountQueryOption("false", _context);
-
-            // Act & Assert
-            Assert.Null(countOption.GetEntityCountFunc(_customers));
-        }
-
         [Fact]
         public void Property_Value_WorksWithUnTypedContext()
         {