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/* ****************************************************************************
*
* Copyright (c) Microsoft Corporation.
*
* This source code is subject to terms and conditions of the Apache License, Version 2.0. A
* copy of the license can be found in the License.html file at the root of this distribution. If
* you cannot locate the Apache License, Version 2.0, please send an email to
* dlr@microsoft.com. By using this source code in any fashion, you are agreeing to be bound
* by the terms of the Apache License, Version 2.0.
*
* You must not remove this notice, or any other, from this software.
*
*
* ***************************************************************************/
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.Dynamic.Utils;
using System.Runtime.CompilerServices;
#if !FEATURE_CORE_DLR
namespace Microsoft.Scripting.Ast {
#else
namespace System.Linq.Expressions {
#endif
/// <summary>
/// Represents calling a constructor and initializing one or more members of the new object.
/// </summary>
[DebuggerTypeProxy(typeof(Expression.MemberInitExpressionProxy))]
public sealed class MemberInitExpression : Expression {
private readonly NewExpression _newExpression;
private readonly ReadOnlyCollection<MemberBinding> _bindings;
internal MemberInitExpression(NewExpression newExpression, ReadOnlyCollection<MemberBinding> bindings) {
_newExpression = newExpression;
_bindings = bindings;
}
/// <summary>
/// Gets the static type of the expression that this <see cref="Expression" /> represents.
/// </summary>
/// <returns>The <see cref="Type"/> that represents the static type of the expression.</returns>
public sealed override Type Type {
get { return _newExpression.Type; }
}
/// <summary>
/// Gets a value that indicates whether the expression tree node can be reduced.
/// </summary>
public override bool CanReduce {
get {
return true;
}
}
/// <summary>
/// Returns the node type of this Expression. Extension nodes should return
/// ExpressionType.Extension when overriding this method.
/// </summary>
/// <returns>The <see cref="ExpressionType"/> of the expression.</returns>
public sealed override ExpressionType NodeType {
get { return ExpressionType.MemberInit; }
}
///<summary>Gets the expression that represents the constructor call.</summary>
///<returns>A <see cref="T:System.Linq.Expressions.NewExpression" /> that represents the constructor call.</returns>
public NewExpression NewExpression {
get { return _newExpression; }
}
///<summary>Gets the bindings that describe how to initialize the members of the newly created object.</summary>
///<returns>A <see cref="T:System.Collections.ObjectModel.ReadOnlyCollection`1" /> of <see cref="T:System.Linq.Expressions.MemberBinding" /> objects which describe how to initialize the members.</returns>
public ReadOnlyCollection<MemberBinding> Bindings {
get { return _bindings; }
}
/// <summary>
/// Dispatches to the specific visit method for this node type.
/// </summary>
protected internal override Expression Accept(ExpressionVisitor visitor) {
return visitor.VisitMemberInit(this);
}
/// <summary>
/// Reduces the <see cref="MemberInitExpression"/> to a simpler expression.
/// If CanReduce returns true, this should return a valid expression.
/// This method is allowed to return another node which itself
/// must be reduced.
/// </summary>
/// <returns>The reduced expression.</returns>
public override Expression Reduce() {
return ReduceMemberInit(_newExpression, _bindings, true);
}
internal static Expression ReduceMemberInit(Expression objExpression, ReadOnlyCollection<MemberBinding> bindings, bool keepOnStack) {
var objVar = Expression.Variable(objExpression.Type, null);
int count = bindings.Count;
var block = new Expression[count + 2];
block[0] = Expression.Assign(objVar, objExpression);
for (int i = 0; i < count; i++) {
block[i + 1] = ReduceMemberBinding(objVar, bindings[i]);
}
block[count + 1] = keepOnStack ? (Expression)objVar : Expression.Empty();
return Expression.Block(new TrueReadOnlyCollection<Expression>(block));
}
internal static Expression ReduceListInit(Expression listExpression, ReadOnlyCollection<ElementInit> initializers, bool keepOnStack) {
var listVar = Expression.Variable(listExpression.Type, null);
int count = initializers.Count;
var block = new Expression[count + 2];
block[0] = Expression.Assign(listVar, listExpression);
for (int i = 0; i < count; i++) {
ElementInit element = initializers[i];
block[i + 1] = Expression.Call(listVar, element.AddMethod, element.Arguments);
}
block[count + 1] = keepOnStack ? (Expression)listVar : Expression.Empty();
return Expression.Block(new TrueReadOnlyCollection<Expression>(block));
}
internal static Expression ReduceMemberBinding(ParameterExpression objVar, MemberBinding binding) {
MemberExpression member = Expression.MakeMemberAccess(objVar, binding.Member);
switch (binding.BindingType) {
case MemberBindingType.Assignment:
return Expression.Assign(member, ((MemberAssignment)binding).Expression);
case MemberBindingType.ListBinding:
return ReduceListInit(member, ((MemberListBinding)binding).Initializers, false);
case MemberBindingType.MemberBinding:
return ReduceMemberInit(member, ((MemberMemberBinding)binding).Bindings, false);
default: throw ContractUtils.Unreachable;
}
}
/// <summary>
/// Creates a new expression that is like this one, but using the
/// supplied children. If all of the children are the same, it will
/// return this expression.
/// </summary>
/// <param name="newExpression">The <see cref="NewExpression" /> property of the result.</param>
/// <param name="bindings">The <see cref="Bindings" /> property of the result.</param>
/// <returns>This expression if no children changed, or an expression with the updated children.</returns>
public MemberInitExpression Update(NewExpression newExpression, IEnumerable<MemberBinding> bindings) {
if (newExpression == NewExpression && bindings == Bindings) {
return this;
}
return Expression.MemberInit(newExpression, bindings);
}
}
public partial class Expression {
///<summary>Creates a <see cref="T:System.Linq.Expressions.MemberInitExpression" />.</summary>
///<returns>A <see cref="T:System.Linq.Expressions.MemberInitExpression" /> that has the <see cref="P:System.Linq.Expressions.Expression.NodeType" /> property equal to <see cref="F:System.Linq.Expressions.ExpressionType.MemberInit" /> and the <see cref="P:System.Linq.Expressions.MemberInitExpression.NewExpression" /> and <see cref="P:System.Linq.Expressions.MemberInitExpression.Bindings" /> properties set to the specified values.</returns>
///<param name="newExpression">A <see cref="T:System.Linq.Expressions.NewExpression" /> to set the <see cref="P:System.Linq.Expressions.MemberInitExpression.NewExpression" /> property equal to.</param>
///<param name="bindings">An array of <see cref="T:System.Linq.Expressions.MemberBinding" /> objects to use to populate the <see cref="P:System.Linq.Expressions.MemberInitExpression.Bindings" /> collection.</param>
///<exception cref="T:System.ArgumentNullException">
///<paramref name="newExpression" /> or <paramref name="bindings" /> is null.</exception>
///<exception cref="T:System.ArgumentException">The <see cref="P:System.Linq.Expressions.MemberBinding.Member" /> property of an element of <paramref name="bindings" /> does not represent a member of the type that <paramref name="newExpression" />.Type represents.</exception>
public static MemberInitExpression MemberInit(NewExpression newExpression, params MemberBinding[] bindings) {
return MemberInit(newExpression, (IEnumerable<MemberBinding>)bindings);
}
///<summary>Creates a <see cref="T:System.Linq.Expressions.MemberInitExpression" />.</summary>
///<returns>A <see cref="T:System.Linq.Expressions.MemberInitExpression" /> that has the <see cref="P:System.Linq.Expressions.Expression.NodeType" /> property equal to <see cref="F:System.Linq.Expressions.ExpressionType.MemberInit" /> and the <see cref="P:System.Linq.Expressions.MemberInitExpression.NewExpression" /> and <see cref="P:System.Linq.Expressions.MemberInitExpression.Bindings" /> properties set to the specified values.</returns>
///<param name="newExpression">A <see cref="T:System.Linq.Expressions.NewExpression" /> to set the <see cref="P:System.Linq.Expressions.MemberInitExpression.NewExpression" /> property equal to.</param>
///<param name="bindings">An <see cref="T:System.Collections.Generic.IEnumerable`1" /> that contains <see cref="T:System.Linq.Expressions.MemberBinding" /> objects to use to populate the <see cref="P:System.Linq.Expressions.MemberInitExpression.Bindings" /> collection.</param>
///<exception cref="T:System.ArgumentNullException">
///<paramref name="newExpression" /> or <paramref name="bindings" /> is null.</exception>
///<exception cref="T:System.ArgumentException">The <see cref="P:System.Linq.Expressions.MemberBinding.Member" /> property of an element of <paramref name="bindings" /> does not represent a member of the type that <paramref name="newExpression" />.Type represents.</exception>
public static MemberInitExpression MemberInit(NewExpression newExpression, IEnumerable<MemberBinding> bindings) {
ContractUtils.RequiresNotNull(newExpression, "newExpression");
ContractUtils.RequiresNotNull(bindings, "bindings");
var roBindings = bindings.ToReadOnly();
ValidateMemberInitArgs(newExpression.Type, roBindings);
return new MemberInitExpression(newExpression, roBindings);
}
}
}
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