Generate conditionals instead of switch in materializer delegate for …

…discriminator values that need custom comparison (#22470) Part of #19650
dotnet · Sep 10, 2020 · 77c16b4 · 77c16b4
1 parent 69ce8af
commit 77c16b4
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Showing 2 changed files with 21 additions and 54 deletions.
diff --git a/src/EFCore/Query/EntityShaperExpression.cs b/src/EFCore/Query/EntityShaperExpression.cs
@@ -111,40 +111,42 @@ protected virtual LambdaExpression GenerateMaterializationCondition([NotNull] IE
                             discriminatorProperty.ClrType, discriminatorProperty.GetIndex(), discriminatorProperty))
                 };
 
-                var switchCases = new SwitchCase[concreteEntityTypes.Length];
-                for (var i = 0; i < concreteEntityTypes.Length; i++)
-                {
-                    var discriminatorValue = Constant(concreteEntityTypes[i].GetDiscriminatorValue(), discriminatorProperty.ClrType);
-                    switchCases[i] = SwitchCase(Constant(concreteEntityTypes[i], typeof(IEntityType)), discriminatorValue);
-                }
-
                 var exception = Block(
                     Throw(
                         Call(
                             _createUnableToDiscriminateException, Constant(entityType),
                             Convert(discriminatorValueVariable, typeof(object)))),
                     Constant(null, typeof(IEntityType)));
 
-
                 var discriminatorComparer = discriminatorProperty.GetKeyValueComparer();
                 if (discriminatorComparer.IsDefault())
                 {
+                    var switchCases = new SwitchCase[concreteEntityTypes.Length];
+                    for (var i = 0; i < concreteEntityTypes.Length; i++)
+                    {
+                        var discriminatorValue = Constant(concreteEntityTypes[i].GetDiscriminatorValue(), discriminatorProperty.ClrType);
+                        switchCases[i] = SwitchCase(Constant(concreteEntityTypes[i], typeof(IEntityType)), discriminatorValue);
+                    }
+
                     expressions.Add(Switch(discriminatorValueVariable, exception, switchCases));
                 }
                 else
                 {
-                    var staticComparer = typeof(StaticDiscriminatorComparer<,,>).MakeGenericType(
-                        discriminatorProperty.DeclaringEntityType.ClrType,
-                        discriminatorProperty.ClrType,
-                        discriminatorProperty.GetTypeMapping().Converter.ProviderClrType);
-
-                    var comparerField = staticComparer.GetField(nameof(StaticDiscriminatorComparer<int, int, int>.Comparer));
-                    comparerField.SetValue(null, discriminatorComparer);
-
-                    var equalsMethod = staticComparer.GetMethod(nameof(StaticDiscriminatorComparer<int, int, int>.DiscriminatorEquals));
-                    expressions.Add(Switch(discriminatorValueVariable, exception, equalsMethod, switchCases));
+                    Expression conditions = exception;
+                    for (var i = concreteEntityTypes.Length - 1; i >= 0; i--)
+                    {
+                        conditions = Condition(
+                            discriminatorComparer.ExtractEqualsBody(
+                                discriminatorValueVariable,
+                                Constant(
+                                    concreteEntityTypes[i].GetDiscriminatorValue(),
+                                    discriminatorProperty.ClrType)),
+                            Constant(concreteEntityTypes[i], typeof(IEntityType)),
+                            conditions);
+                    }
+
+                    expressions.Add(conditions);
                 }
-
                 body = Block(new[] { discriminatorValueVariable }, expressions);
             }
             else

diff --git a/src/EFCore/Query/Internal/StaticDiscriminatorComparer.cs b/src/EFCore/Query/Internal/StaticDiscriminatorComparer.cs