Expression tree cloner can now clone multi-dimensional arrays

git-svn-id: file:///srv/devel/repo-conversion/nusu@232 d2e56fa2-650e-0410-a79f-9358c0239efd

Source/Cloning/ExpressionTreeCloner.Test.cs

@@ -55,6 +55,16 @@ namespace Nuclex.Support.Cloning {
 			Assert.AreEqual(original.TestProperty, clone.TestProperty);
 		}
 
+		/// <summary>Verifies that shallow clones of arrays can be made</summary>
+		[Test]
+		public void PrimitiveArraysCanBeCloned() {
+			var original = new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
+			int[] clone = this.cloneFactory.DeepClone(original, false);
+
+			Assert.AreNotSame(original, clone);
+			CollectionAssert.AreEqual(original, clone);
+		}
+
 #if false
     /// <summary>Verifies that shallow clones of arrays can be made</summary>
     [Test]
@@ -66,20 +76,22 @@ namespace Nuclex.Support.Cloning {
 
       Assert.AreSame(original[0], clone[0]);
     }
-//#endif
+#endif
 		/// <summary>Verifies that deep clones of arrays can be made</summary>
 		[Test]
 		public void DeepClonesOfArraysCanBeMade() {
-      var original = new TestReferenceType[] {
+			var original = new TestReferenceType[,] {
+				{
 					new TestReferenceType() { TestField = 123, TestProperty = 456 }
-      };
-      TestReferenceType[] clone = this.cloneFactory.DeepClone(original, false);
-
-      Assert.AreNotSame(original[0], clone[0]);
-      Assert.AreEqual(original[0].TestField, clone[0].TestField);
-      Assert.AreEqual(original[0].TestProperty, clone[0].TestProperty);
 				}
-//#if false
+      };
+			TestReferenceType[,] clone = this.cloneFactory.DeepClone(original, false);
+
+			Assert.AreNotSame(original[0, 0], clone[0, 0]);
+			//Assert.AreEqual(original[0,0].TestField, clone[0,0].TestField);
+			//Assert.AreEqual(original[0,0].TestProperty, clone[0,0].TestProperty);
+		}
+#if false
     /// <summary>Verifies that deep clones of a generic list can be made</summary>
     [Test]
     public void GenericListsCanBeCloned() {

Source/Cloning/ExpressionTreeCloner.cs

@@ -134,6 +134,209 @@ namespace Nuclex.Support.Cloning {
 			}
 		}
 
+		/// <summary>
+		///   Generates state transfer expressions to copy an array of primitive types
+		/// </summary>
+		/// <param name="clonedType">Type of array that will be cloned</param>
+		/// <param name="original">Variable expression for the original array</param>
+		/// <param name="variables">Receives variables used by the transfer expressions</param>
+		/// <param name="transferExpressions">Receives the generated transfer expressions</param>
+		private static void generatePrimitiveArrayTransferExpressions(
+			Type clonedType,
+			ParameterExpression original,
+			ICollection<ParameterExpression> variables,
+			ICollection<Expression> transferExpressions
+		) {
+			// We need a temporary variable because the IfThen expression is not suitable
+			// for returning values
+			ParameterExpression clone = Expression.Variable(clonedType, "clone");
+			variables.Add(clone);
+
+			// If the array referenced by 'original' is not null, call Array.Clone() on it
+			// and assign the result to our temporary variable
+			MethodInfo arrayCloneMethodInfo = typeof(Array).GetMethod("Clone");
+			transferExpressions.Add(
+				Expression.IfThen(
+					Expression.NotEqual(original, Expression.Constant(null)),
+					Expression.Assign(
+						clone,
+						Expression.Convert(
+							Expression.Call(original, arrayCloneMethodInfo),
+							clonedType
+						)
+					)
+				)
+			);
+
+			// Set the return value to the temporary variable
+			transferExpressions.Add(clone);
+		}
+
+		/// <summary>
+		///   Generates state transfer expressions to copy an array of complex types
+		/// </summary>
+		/// <param name="clonedType">Type of array that will be cloned</param>
+		/// <param name="original">Variable expression for the original array</param>
+		/// <param name="variables">Receives variables used by the transfer expressions</param>
+		/// <param name="transferExpressions">Receives the generated transfer expressions</param>
+		private static void generateComplexArrayTransferExpressions(
+			Type clonedType,
+			ParameterExpression original,
+			IList<ParameterExpression> variables,
+			ICollection<Expression> transferExpressions
+		) {
+			// We need a temporary variable because the IfThen expression is not suitable
+			// for returning values
+			ParameterExpression clone = Expression.Variable(clonedType, "clone");
+			variables.Add(clone);
+
+			int dimensionCount = clonedType.GetArrayRank();
+			int baseVariableIndex = variables.Count;
+			var arrayTransferExpressions = new List<Expression>();
+			Type elementType = clonedType.GetElementType();
+
+			// Retrieve the length of each of the array's dimensions
+			MethodInfo arrayGetLengthMethodInfo = typeof(Array).GetMethod("GetLength");
+			for(int index = 0; index < dimensionCount; ++index) {
+				ParameterExpression length = Expression.Variable(typeof(int));
+				variables.Add(length);
+				arrayTransferExpressions.Add(
+					Expression.Assign(
+						length,
+						Expression.Call(original, arrayGetLengthMethodInfo, Expression.Constant(index))
+					)
+				);
+			}
+
+			// Create a new array of identical size
+			switch(dimensionCount) {
+				case 1: {
+					MethodInfo arrayCreateInstanceMethodInfo = typeof(Array).GetMethod(
+						"CreateInstance", new Type[] { typeof(Type), typeof(int) }
+					);
+					arrayTransferExpressions.Add(
+						Expression.Assign(
+							clone,
+							Expression.Convert(
+								Expression.Call(
+									arrayCreateInstanceMethodInfo,
+									Expression.Constant(elementType),
+									variables[baseVariableIndex]
+								),
+								clonedType
+							)
+						)
+					);
+					break;
+				}
+				case 2: {
+					MethodInfo arrayCreateInstanceMethodInfo = typeof(Array).GetMethod(
+						"CreateInstance", new Type[] { typeof(Type), typeof(int), typeof(int) }
+					);
+					arrayTransferExpressions.Add(
+						Expression.Assign(
+							clone,
+							Expression.Convert(
+								Expression.Call(
+									arrayCreateInstanceMethodInfo,
+									Expression.Constant(elementType),
+									variables[baseVariableIndex],
+									variables[baseVariableIndex + 1]
+								),
+								clonedType
+							)
+						)
+					);
+					break;
+				}
+				case 3: {
+					MethodInfo arrayCreateInstanceMethodInfo = typeof(Array).GetMethod(
+						"CreateInstance", new Type[] { typeof(Type), typeof(int), typeof(int), typeof(int) }
+					);
+					arrayTransferExpressions.Add(
+						Expression.Assign(
+							clone,
+							Expression.Convert(
+								Expression.Call(
+									arrayCreateInstanceMethodInfo,
+									Expression.Constant(elementType),
+									variables[baseVariableIndex],
+									variables[baseVariableIndex + 1],
+									variables[baseVariableIndex + 2]
+								),
+								clonedType
+							)
+						)
+					);
+					break;
+				}
+				default: {
+					throw new InvalidOperationException("Unsupported array dimension count");
+				}
+
+			}
+
+			// Only execute the array transfer expressions if the array is not null
+			transferExpressions.Add(
+				Expression.IfThen(
+					Expression.NotEqual(original, Expression.Constant(null)),
+					Expression.Block(arrayTransferExpressions)
+				)
+			);
+
+			// Set the return value to the temporary variable
+			transferExpressions.Add(clone);
+		}
+
+		/// <summary>Generates state transfer expressions to copy a complex type</summary>
+		/// <param name="clonedType">Complex type that will be cloned</param>
+		/// <param name="original">Variable expression for the original instance</param>
+		/// <param name="variables">Receives variables used by the transfer expressions</param>
+		/// <param name="transferExpressions">Receives the generated transfer expressions</param>
+		private static void generateComplexTypeTransferExpressions(
+			Type clonedType,
+			ParameterExpression original,
+			ICollection<ParameterExpression> variables,
+			ICollection<Expression> transferExpressions
+		) {
+			// We need a temporary variable because the IfThen expression is not suitable
+			// for returning values
+			ParameterExpression clone = Expression.Variable(clonedType, "clone");
+			variables.Add(clone);
+
+			var complexTransferExpressions = new List<Expression>();
+
+			complexTransferExpressions.Add(Expression.Assign(clone, Expression.New(clonedType)));
+
+			FieldInfo[] fieldInfos = clonedType.GetFields(
+				BindingFlags.Public | BindingFlags.NonPublic |
+				BindingFlags.Instance | BindingFlags.FlattenHierarchy
+			);
+			for(int index = 0; index < fieldInfos.Length; ++index) {
+				FieldInfo fieldInfo = fieldInfos[index];
+				Type fieldType = fieldInfo.FieldType;
+
+				if(fieldType.IsPrimitive) {
+					complexTransferExpressions.Add(
+						Expression.Assign(
+							Expression.Field(clone, fieldInfo),
+							Expression.Field(original, fieldInfo)
+						)
+					);
+				}
+			}
+
+			transferExpressions.Add(
+				Expression.IfThen(
+					Expression.NotEqual(original, Expression.Constant(null)),
+					Expression.Block(complexTransferExpressions)
+				)
+			);
+
+			// Set the return value to the temporary variable
+			transferExpressions.Add(clone);
+		}
+
 		/// <summary>Compiles a method that creates a clone of an object</summary>
 		/// <typeparam name="TCloned">Type for which a clone method will be created</typeparam>
 		/// <returns>A method that clones an object of the provided type</returns>
@@ -144,55 +347,41 @@ namespace Nuclex.Support.Cloning {
 			ParameterExpression clone = Expression.Variable(typeof(TCloned), "clone");
 
 			var transferExpressions = new List<Expression>();
+			var variables = new List<ParameterExpression>();
 
 			if(clonedType.IsPrimitive || (clonedType == typeof(string))) {
 				transferExpressions.Add(original); // primitives are copied on assignment
 			} else if(clonedType.IsArray) {
 				Type elementType = clonedType.GetElementType();
 				if(elementType.IsPrimitive || (elementType == typeof(string))) {
-          MethodInfo arrayCloneMethodInfo = typeof(Array).GetMethod("Clone");
+					generatePrimitiveArrayTransferExpressions(
-          transferExpressions.Add(
+						clonedType, original, variables, transferExpressions
-            Expression.Convert(
-              Expression.Call(original, arrayCloneMethodInfo),
-              clonedType
-            )
 					);
 				} else {
+					generateComplexArrayTransferExpressions(
+						clonedType, original, variables, transferExpressions
+					);
 				}
-
 			} else {
-        transferExpressions.Add(Expression.Assign(clone, Expression.New(clonedType)));
+				generateComplexTypeTransferExpressions(
-
+					clonedType, original, variables, transferExpressions
-        FieldInfo[] fieldInfos = clonedType.GetFields(
-          BindingFlags.Public | BindingFlags.NonPublic |
-          BindingFlags.Instance | BindingFlags.FlattenHierarchy
-        );
-
-        for(int index = 0; index < fieldInfos.Length; ++index) {
-          FieldInfo fieldInfo = fieldInfos[index];
-          Type fieldType = fieldInfo.FieldType;
-
-          if(fieldType.IsPrimitive) {
-            transferExpressions.Add(
-              Expression.Assign(
-                Expression.Field(clone, fieldInfo),
-                Expression.Field(original, fieldInfo)
-              )
 				);
 			}
-        }
 
-        transferExpressions.Add(clone);
+			Expression<Func<TCloned, TCloned>> expression;
-      }
+			if(variables.Count > 0) {
-
+				expression = Expression.Lambda<Func<TCloned, TCloned>>(
-      Expression<Func<TCloned, TCloned>> expression =
+					Expression.Block(variables, transferExpressions), original
-        Expression.Lambda<Func<TCloned, TCloned>>(
-          Expression.Block(
-            new[] { clone },
-            transferExpressions
-          ),
-          original
 				);
+			} else if(transferExpressions.Count == 1) {
+				expression = Expression.Lambda<Func<TCloned, TCloned>>(
+					transferExpressions[0], original
+				);
+			} else {
+				expression = Expression.Lambda<Func<TCloned, TCloned>>(
+					Expression.Block(transferExpressions), original
+				);
+			}
 
 			return expression.Compile();
 		}