Support comparison operations for Guid (#342)

Author: AlekseyMartynov

net/DevExtreme.AspNet.Data.Tests.Xpo/Bug339.cs

@@ -0,0 +1,38 @@
+using DevExpress.Xpo;
+using System;
+using Xunit;
+
+namespace DevExtreme.AspNet.Data.Tests.Xpo {
+
+    public class Bug339 {
+
+        [Persistent(nameof(Bug339) + "_" + nameof(DataItem))]
+        public class DataItem {
+            [Key]
+            public Guid ID { get; set; }
+        }
+
+        [Fact]
+        public void Scenario() {
+            var guid1 = "".PadLeft(32, '1');
+            var guid2 = "".PadLeft(32, '2');
+
+            UnitOfWorkHelper.Exec(uow => {
+                uow.Save(new DataItem { ID = new Guid(guid1) });
+                uow.Save(new DataItem { ID = new Guid(guid2) });
+
+                uow.CommitChanges();
+
+                var loadResult = DataSourceLoader.Load(uow.Query<DataItem>(), new SampleLoadOptions {
+                    Filter = new[] { "ID", "<", guid2 },
+                    RequireTotalCount = true
+                });
+
+                Assert.Equal(1, loadResult.totalCount);
+            });
+
+        }
+
+    }
+
+}

net/DevExtreme.AspNet.Data.Tests.Xpo/UnitOfWorkHelper.cs

@@ -21,7 +21,8 @@ public static void Exec(Action<UnitOfWork> action) {
                     dict.GetDataStoreSchema(
                         typeof(DefaultSort.DataItem),
                         typeof(RemoteGroupingStress.DataItem),
-                        typeof(Summary.DataItem)
+                        typeof(Summary.DataItem),
+                        typeof(Bug339.DataItem)
                     );
 
                     var provider = XpoDefault.GetConnectionProvider(

net/DevExtreme.AspNet.Data.Tests/FilterExpressionCompilerTests.cs

@@ -290,6 +290,33 @@ string CompileOperation(string op) {
             Assert.Equal("False", CompileOperation("<="));
         }
 
+        [Fact]
+        public void GuidComparison() {
+            // https://github.com/DevExpress/DevExtreme.AspNet.Data/issues/339
+
+            var sampleGuid = Guid.Empty.ToString();
+
+            Assert.Equal(
+                $"(obj.CompareTo({sampleGuid}) > 0)",
+                Compile<Guid>(new[] { "this", ">", sampleGuid }).Body.ToString()
+            );
+
+            Assert.Equal(
+                $"(obj.Value.CompareTo({sampleGuid}) < 0)",
+                Compile<Guid?>(new[] { "this", "<", sampleGuid }).Body.ToString()
+            );
+
+            Assert.Equal(
+                $"IIF((obj == null), False, (obj.Value.CompareTo({sampleGuid}) >= 0))",
+                Compile<Guid?>(new[] { "this", ">=", sampleGuid }, true).Body.ToString()
+            );
+
+            Assert.Equal(
+                "False",
+                Compile<Guid?>(new[] { "this", "<=", null }).Body.ToString()
+            );
+        }
+
     }
 
 }

net/DevExtreme.AspNet.Data/FilterExpressionCompiler.cs

@@ -88,15 +88,27 @@ Expression CompileBinary(ParameterExpression dataItemExpr, IList criteriaJson) {
                 if(_stringToLower && clientValue is String)
                     clientValue = ((string)clientValue).ToLower();
 
+                if((accessorExpr.Type == typeof(Guid) || accessorExpr.Type == typeof(Guid?)) && IsInequality(expressionType))
+                    return CompileGuidComparison(accessorExpr, expressionType, clientValue);
+
                 Expression valueExpr = Expression.Constant(clientValue, accessorExpr.Type);
 
                 if(accessorExpr.Type == typeof(String) && IsInequality(expressionType)) {
                     var compareMethod = typeof(String).GetMethod(nameof(String.Compare), new[] { typeof(String), typeof(String) });
-                    accessorExpr = Expression.Call(null, compareMethod, accessorExpr, valueExpr);
-                    valueExpr = Expression.Constant(0);
-                } else if(useDynamicBinding) {
-                    accessorExpr = Expression.Call(typeof(Utils).GetMethod(nameof(Utils.DynamicCompare)), accessorExpr, valueExpr);
-                    valueExpr = Expression.Constant(0);
+                    return Expression.MakeBinary(
+                        expressionType,
+                        Expression.Call(compareMethod, accessorExpr, valueExpr),
+                        Expression.Constant(0)
+                    );
+                }
+
+                if(useDynamicBinding) {
+                    var compareMethod = typeof(Utils).GetMethod(nameof(Utils.DynamicCompare));
+                    return Expression.MakeBinary(
+                        expressionType,
+                        Expression.Call(compareMethod, accessorExpr, valueExpr),
+                        Expression.Constant(0)
+                    );
                 }
 
                 return Expression.MakeBinary(expressionType, accessorExpr, valueExpr);
@@ -108,6 +120,31 @@ bool IsInequality(ExpressionType type) {
             return type == ExpressionType.LessThan || type == ExpressionType.LessThanOrEqual || type == ExpressionType.GreaterThanOrEqual || type == ExpressionType.GreaterThan;
         }
 
+        Expression CompileGuidComparison(Expression accessorExpr, ExpressionType expressionType, object clientValue) {
+            if(clientValue == null)
+                return Expression.Constant(false);
+
+            var result = Expression.MakeBinary(
+                expressionType,
+                Expression.Call(
+                    Utils.IsNullable(accessorExpr.Type) ? Expression.Property(accessorExpr, "Value") : accessorExpr,
+                    typeof(Guid).GetMethod(nameof(Guid.CompareTo), new[] { typeof(Guid) }),
+                    Expression.Constant(clientValue, typeof(Guid))
+                ),
+                Expression.Constant(0)
+            );
+
+            if(GuardNulls) {
+                return Expression.Condition(
+                    Expression.MakeBinary(ExpressionType.Equal, accessorExpr, Expression.Constant(null)),
+                    Expression.Constant(false),
+                    result
+                );
+            }
+
+            return result;
+        }
+
         Expression CompileStringFunction(Expression accessorExpr, string clientOperation, string value) {
             if(_stringToLower && value != null)
                 value = value.ToLower();