/* ****************************************************************************
*
* Copyright (c) Microsoft Corporation.
*
* This source code is subject to terms and conditions of the Microsoft Public License. A
* copy of the license can be found in the License.html file at the root of this distribution. If
* you cannot locate the Microsoft Public License, 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 Microsoft Public License.
*
* 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.Reflection;
using System.Runtime.CompilerServices;
using System.Text;
#if SILVERLIGHT
using System.Core;
#endif
#if CLR2
namespace Microsoft.Scripting.Ast{
#else
namespace System.Linq.Expressions {
#endif
/// <summary>
/// Represents indexing a property or array.
/// </summary>
#if !SILVERLIGHT
[DebuggerTypeProxy(typeof(Expression.IndexExpressionProxy))]
#endif
public sealed class IndexExpression : Expression, IArgumentProvider {
private readonly Expression _instance;
private readonly PropertyInfo _indexer;
private IList<Expression> _arguments;
internal IndexExpression(
Expression instance,
PropertyInfo indexer,
IList<Expression> arguments) {
if (indexer == null) {
Debug.Assert(instance != null && instance.Type.IsArray);
Debug.Assert(instance.Type.GetArrayRank() == arguments.Count);
}
_instance = instance;
_indexer = indexer;
_arguments = arguments;
}
/// <summary>
/// Returns the node type of this <see cref="Expression" />. (Inherited from <see cref="Expression" />.)
/// </summary>
/// <returns>The <see cref="ExpressionType"/> that represents this expression.</returns>
public sealed override ExpressionType NodeType {
get { return ExpressionType.Index; }
}
/// <summary>
/// Gets the static type of the expression that this <see cref="Expression" /> represents. (Inherited from <see cref="Expression"/>.)
/// </summary>
/// <returns>The <see cref="Type"/> that represents the static type of the expression.</returns>
public sealed override Type Type {
get {
if (_indexer != null) {
return _indexer.PropertyType;
}
return _instance.Type.GetElementType();
}
}
/// <summary>
/// An object to index.
/// </summary>
public Expression Object {
get { return _instance; }
}
/// <summary>
/// Gets the <see cref="PropertyInfo"/> for the property if the expression represents an indexed property, returns null otherwise.
/// </summary>
public PropertyInfo Indexer {
get { return _indexer; }
}
/// <summary>
/// Gets the arguments to be used to index the property or array.
/// </summary>
public ReadOnlyCollection<Expression> Arguments {
get { return ReturnReadOnly(ref _arguments); }
}
/// <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="object">The <see cref="Object" /> property of the result.</param>
/// <param name="arguments">The <see cref="Arguments" /> property of the result.</param>
/// <returns>This expression if no children changed, or an expression with the updated children.</returns>
public IndexExpression Update(Expression @object, IEnumerable<Expression> arguments) {
if (@object == Object && arguments == Arguments) {
return this;
}
return Expression.MakeIndex(@object, Indexer, arguments);
}
Expression IArgumentProvider.GetArgument(int index) {
return _arguments[index];
}
int IArgumentProvider.ArgumentCount {
get {
return _arguments.Count;
}
}
/// <summary>
/// Dispatches to the specific visit method for this node type.
/// </summary>
protected internal override Expression Accept(ExpressionVisitor visitor) {
return visitor.VisitIndex(this);
}
internal Expression Rewrite(Expression instance, Expression[] arguments) {
Debug.Assert(instance != null);
Debug.Assert(arguments == null || arguments.Length == _arguments.Count);
return Expression.MakeIndex(instance, _indexer, arguments ?? _arguments);
}
}
public partial class Expression {
/// <summary>
/// Creates an <see cref="IndexExpression"/> that represents accessing an indexed property in an object.
/// </summary>
/// <param name="instance">The object to which the property belongs. Should be null if the property is static(shared).</param>
/// <param name="indexer">An <see cref="Expression"/> representing the property to index.</param>
/// <param name="arguments">An IEnumerable{Expression} contaning the arguments to be used to index the property.</param>
/// <returns>The created <see cref="IndexExpression"/>.</returns>
public static IndexExpression MakeIndex(Expression instance, PropertyInfo indexer, IEnumerable<Expression> arguments) {
if (indexer != null) {
return Property(instance, indexer, arguments);
} else {
return ArrayAccess(instance, arguments);
}
}
#region ArrayAccess
/// <summary>
/// Creates an <see cref="IndexExpression"></see> to access an array.
/// </summary>
/// <param name="array">An expression representing the array to index.</param>
/// <param name="indexes">An array containing expressions used to index the array.</param>
/// <remarks>The expression representing the array can be obtained by using the MakeMemberAccess method,
/// or through NewArrayBounds or NewArrayInit.</remarks>
/// <returns>The created <see cref="IndexExpression"/>.</returns>
public static IndexExpression ArrayAccess(Expression array, params Expression[] indexes) {
return ArrayAccess(array, (IEnumerable<Expression>)indexes);
}
/// <summary>
/// Creates an <see cref="IndexExpression"></see> to access an array.
/// </summary>
/// <param name="array">An expression representing the array to index.</param>
/// <param name="indexes">An <see cref="IEnumerable{Expression}"/> containing expressions used to index the array.</param>
/// <remarks>The expression representing the array can be obtained by using the MakeMemberAccess method,
/// or through NewArrayBounds or NewArrayInit.</remarks>
/// <returns>The created <see cref="IndexExpression"/>.</returns>
public static IndexExpression ArrayAccess(Expression array, IEnumerable<Expression> indexes) {
RequiresCanRead(array, "array");
Type arrayType = array.Type;
if (!arrayType.IsArray) {
throw Error.ArgumentMustBeArray();
}
var indexList = indexes.ToReadOnly();
if (arrayType.GetArrayRank() != indexList.Count) {
throw Error.IncorrectNumberOfIndexes();
}
foreach (Expression e in indexList) {
RequiresCanRead(e, "indexes");
if (e.Type != typeof(int)) {
throw Error.ArgumentMustBeArrayIndexType();
}
}
return new IndexExpression(array, null, indexList);
}
#endregion
#region Property
/// <summary>
/// Creates an <see cref="IndexExpression"/> representing the access to an indexed property.
/// </summary>
/// <param name="instance">The object to which the property belongs. If the property is static/shared, it must be null.</param>
/// <param name="propertyName">The name of the indexer.</param>
/// <param name="arguments">An array of <see cref="Expression"/> objects that are used to index the property.</param>
/// <returns>The created <see cref="IndexExpression"/>.</returns>
public static IndexExpression Property(Expression instance, string propertyName, params Expression[] arguments) {
RequiresCanRead(instance, "instance");
ContractUtils.RequiresNotNull(propertyName, "indexerName");
PropertyInfo pi = FindInstanceProperty(instance.Type, propertyName, arguments);
return Property(instance, pi, arguments);
}
#region methods for finding a PropertyInfo by its name
/// <summary>
/// The method finds the instance property with the specified name in a type. The property's type signature needs to be compatible with
/// the arguments if it is a indexer. If the arguments is null or empty, we get a normal property.
/// </summary>
private static PropertyInfo FindInstanceProperty(Type type, string propertyName, Expression[] arguments) {
// bind to public names first
BindingFlags flags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.IgnoreCase | BindingFlags.FlattenHierarchy;
PropertyInfo pi = FindProperty(type, propertyName, arguments, flags);
if (pi == null) {
flags = BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.IgnoreCase | BindingFlags.FlattenHierarchy;
pi = FindProperty(type, propertyName, arguments, flags);
}
if (pi == null) {
if (arguments == null || arguments.Length == 0) {
throw Error.InstancePropertyWithoutParameterNotDefinedForType(propertyName, type);
} else {
throw Error.InstancePropertyWithSpecifiedParametersNotDefinedForType(propertyName, GetArgTypesString(arguments), type);
}
}
return pi;
}
private static string GetArgTypesString(Expression[] arguments) {
StringBuilder argTypesStr = new StringBuilder();
var isFirst = true;
argTypesStr.Append("(");
foreach (var t in arguments.Select(arg => arg.Type)) {
if (!isFirst) {
argTypesStr.Append(", ");
}
argTypesStr.Append(t.Name);
isFirst = false;
}
argTypesStr.Append(")");
return argTypesStr.ToString();
}
private static PropertyInfo FindProperty(Type type, string propertyName, Expression[] arguments, BindingFlags flags) {
MemberInfo[] members = type.FindMembers(MemberTypes.Property, flags, Type.FilterNameIgnoreCase, propertyName);
if (members == null || members.Length == 0)
return null;
PropertyInfo pi;
var propertyInfos = members.Map(t => (PropertyInfo)t);
int count = FindBestProperty(propertyInfos, arguments, out pi);
if (count == 0)
return null;
if (count > 1)
throw Error.PropertyWithMoreThanOneMatch(propertyName, type);
return pi;
}
private static int FindBestProperty(IEnumerable<PropertyInfo> properties, Expression[] args, out PropertyInfo property) {
int count = 0;
property = null;
foreach (PropertyInfo pi in properties) {
if (pi != null && IsCompatible(pi, args)) {
if (property == null) {
property = pi;
count = 1;
}
else {
count++;
}
}
}
return count;
}
private static bool IsCompatible(PropertyInfo pi, Expression[] args) {
MethodInfo mi;
mi = pi.GetGetMethod(true);
ParameterInfo[] parms;
if (mi != null) {
parms = mi.GetParametersCached();
} else {
mi = pi.GetSetMethod(true);
//The setter has an additional parameter for the value to set,
//need to remove the last type to match the arguments.
parms = mi.GetParametersCached().RemoveLast();
}
if (mi == null) {
return false;
}
if (args == null) {
return parms.Length == 0;
}
if (parms.Length != args.Length)
return false;
for (int i = 0; i < args.Length; i++) {
if (args[i] == null) return false;
if (!TypeUtils.AreReferenceAssignable(parms[i].ParameterType, args[i].Type)) {
return false;
}
}
return true;
}
#endregion
/// <summary>
/// Creates an <see cref="IndexExpression"/> representing the access to an indexed property.
/// </summary>
/// <param name="instance">The object to which the property belongs. If the property is static/shared, it must be null.</param>
/// <param name="indexer">The <see cref="PropertyInfo"/> that represents the property to index.</param>
/// <param name="arguments">An array of <see cref="Expression"/> objects that are used to index the property.</param>
/// <returns>The created <see cref="IndexExpression"/>.</returns>
public static IndexExpression Property(Expression instance, PropertyInfo indexer, params Expression[] arguments) {
return Property(instance, indexer, (IEnumerable<Expression>)arguments);
}
/// <summary>
/// Creates an <see cref="IndexExpression"/> representing the access to an indexed property.
/// </summary>
/// <param name="instance">The object to which the property belongs. If the property is static/shared, it must be null.</param>
/// <param name="indexer">The <see cref="PropertyInfo"/> that represents the property to index.</param>
/// <param name="arguments">An <see cref="IEnumerable{T}"/> of <see cref="Expression"/> objects that are used to index the property.</param>
/// <returns>The created <see cref="IndexExpression"/>.</returns>
public static IndexExpression Property(Expression instance, PropertyInfo indexer, IEnumerable<Expression> arguments) {
var argList = arguments.ToReadOnly();
ValidateIndexedProperty(instance, indexer, ref argList);
return new IndexExpression(instance, indexer, argList);
}
// CTS places no restrictions on properties (see ECMA-335 8.11.3),
// so we validate that the property conforms to CLS rules here.
//
// Does reflection help us out at all? Expression.Property skips all of
// these checks, so either it needs more checks or we need less here.
private static void ValidateIndexedProperty(Expression instance, PropertyInfo property, ref ReadOnlyCollection<Expression> argList) {
// If both getter and setter specified, all their parameter types
// should match, with exception of the last setter parameter which
// should match the type returned by the get method.
// Accessor parameters cannot be ByRef.
ContractUtils.RequiresNotNull(property, "property");
if (property.PropertyType.IsByRef) throw Error.PropertyCannotHaveRefType();
if (property.PropertyType == typeof(void)) throw Error.PropertyTypeCannotBeVoid();
ParameterInfo[] getParameters = null;
MethodInfo getter = property.GetGetMethod(true);
if (getter != null) {
getParameters = getter.GetParametersCached();
ValidateAccessor(instance, getter, getParameters, ref argList);
}
MethodInfo setter = property.GetSetMethod(true);
if (setter != null) {
ParameterInfo[] setParameters = setter.GetParametersCached();
if (setParameters.Length == 0) throw Error.SetterHasNoParams();
// valueType is the type of the value passed to the setter (last parameter)
Type valueType = setParameters[setParameters.Length - 1].ParameterType;
if (valueType.IsByRef) throw Error.PropertyCannotHaveRefType();
if (setter.ReturnType != typeof(void)) throw Error.SetterMustBeVoid();
if (property.PropertyType != valueType) throw Error.PropertyTyepMustMatchSetter();
if (getter != null) {
if (getter.IsStatic ^ setter.IsStatic) throw Error.BothAccessorsMustBeStatic();
if (getParameters.Length != setParameters.Length - 1) throw Error.IndexesOfSetGetMustMatch();
for (int i = 0; i < getParameters.Length; i++) {
if (getParameters[i].ParameterType != setParameters[i].ParameterType) throw Error.IndexesOfSetGetMustMatch();
}
} else {
ValidateAccessor(instance, setter, setParameters.RemoveLast(), ref argList);
}
}
if (getter == null && setter == null) {
throw Error.PropertyDoesNotHaveAccessor(property);
}
}
private static void ValidateAccessor(Expression instance, MethodInfo method, ParameterInfo[] indexes, ref ReadOnlyCollection<Expression> arguments) {
ContractUtils.RequiresNotNull(arguments, "arguments");
ValidateMethodInfo(method);
if ((method.CallingConvention & CallingConventions.VarArgs) != 0) throw Error.AccessorsCannotHaveVarArgs();
if (method.IsStatic) {
if (instance != null) throw Error.OnlyStaticMethodsHaveNullInstance();
} else {
if (instance == null) throw Error.OnlyStaticMethodsHaveNullInstance();
RequiresCanRead(instance, "instance");
ValidateCallInstanceType(instance.Type, method);
}
ValidateAccessorArgumentTypes(method, indexes, ref arguments);
}
private static void ValidateAccessorArgumentTypes(MethodInfo method, ParameterInfo[] indexes, ref ReadOnlyCollection<Expression> arguments) {
if (indexes.Length > 0) {
if (indexes.Length != arguments.Count) {
throw Error.IncorrectNumberOfMethodCallArguments(method);
}
Expression[] newArgs = null;
for (int i = 0, n = indexes.Length; i < n; i++) {
Expression arg = arguments[i];
ParameterInfo pi = indexes[i];
RequiresCanRead(arg, "arguments");
Type pType = pi.ParameterType;
if (pType.IsByRef) throw Error.AccessorsCannotHaveByRefArgs();
TypeUtils.ValidateType(pType);
if (!TypeUtils.AreReferenceAssignable(pType, arg.Type)) {
if (TypeUtils.IsSameOrSubclass(typeof(LambdaExpression), pType) && pType.IsAssignableFrom(arg.GetType())) {
arg = Expression.Quote(arg);
} else {
throw Error.ExpressionTypeDoesNotMatchMethodParameter(arg.Type, pType, method);
}
}
if (newArgs == null && arg != arguments[i]) {
newArgs = new Expression[arguments.Count];
for (int j = 0; j < i; j++) {
newArgs[j] = arguments[j];
}
}
if (newArgs != null) {
newArgs[i] = arg;
}
}
if (newArgs != null) {
arguments = new TrueReadOnlyCollection<Expression>(newArgs);
}
} else if (arguments.Count > 0) {
throw Error.IncorrectNumberOfMethodCallArguments(method);
}
}
#endregion
}
}
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