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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.
*
*
* ***************************************************************************/
#if CLR2
using Microsoft.Scripting.Ast;
#else
using System.Linq.Expressions;
#endif
#if SILVERLIGHT
using System.Core;
#else
using System.Runtime.Remoting;
#endif
using System.Collections.Generic;
using System.Dynamic.Utils;
using System.Reflection;
namespace System.Dynamic {
/// <summary>
/// Represents the dynamic binding and a binding logic of an object participating in the dynamic binding.
/// </summary>
public class DynamicMetaObject {
private readonly Expression _expression;
private readonly BindingRestrictions _restrictions;
private readonly object _value;
private readonly bool _hasValue;
/// <summary>
/// Represents an empty array of type <see cref="DynamicMetaObject"/>. This field is read only.
/// </summary>
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Security", "CA2105:ArrayFieldsShouldNotBeReadOnly")]
public static readonly DynamicMetaObject[] EmptyMetaObjects = new DynamicMetaObject[0];
/// <summary>
/// Initializes a new instance of the <see cref="DynamicMetaObject"/> class.
/// </summary>
/// <param name="expression">The expression representing this <see cref="DynamicMetaObject"/> during the dynamic binding process.</param>
/// <param name="restrictions">The set of binding restrictions under which the binding is valid.</param>
public DynamicMetaObject(Expression expression, BindingRestrictions restrictions) {
ContractUtils.RequiresNotNull(expression, "expression");
ContractUtils.RequiresNotNull(restrictions, "restrictions");
_expression = expression;
_restrictions = restrictions;
}
/// <summary>
/// Initializes a new instance of the <see cref="DynamicMetaObject"/> class.
/// </summary>
/// <param name="expression">The expression representing this <see cref="DynamicMetaObject"/> during the dynamic binding process.</param>
/// <param name="restrictions">The set of binding restrictions under which the binding is valid.</param>
/// <param name="value">The runtime value represented by the <see cref="DynamicMetaObject"/>.</param>
public DynamicMetaObject(Expression expression, BindingRestrictions restrictions, object value)
: this(expression, restrictions) {
_value = value;
_hasValue = true;
}
/// <summary>
/// The expression representing the <see cref="DynamicMetaObject"/> during the dynamic binding process.
/// </summary>
public Expression Expression {
get {
return _expression;
}
}
/// <summary>
/// The set of binding restrictions under which the binding is valid.
/// </summary>
public BindingRestrictions Restrictions {
get {
return _restrictions;
}
}
/// <summary>
/// The runtime value represented by this <see cref="DynamicMetaObject"/>.
/// </summary>
public object Value {
get {
return _value;
}
}
/// <summary>
/// Gets a value indicating whether the <see cref="DynamicMetaObject"/> has the runtime value.
/// </summary>
public bool HasValue {
get {
return _hasValue;
}
}
/// <summary>
/// Gets the <see cref="Type"/> of the runtime value or null if the <see cref="DynamicMetaObject"/> has no value associated with it.
/// </summary>
public Type RuntimeType {
get {
if (_hasValue) {
Type ct = Expression.Type;
// valuetype at compile tyme, type cannot change.
if (ct.IsValueType) {
return ct;
}
if (_value != null) {
return _value.GetType();
} else {
return null;
}
} else {
return null;
}
}
}
/// <summary>
/// Gets the limit type of the <see cref="DynamicMetaObject"/>.
/// </summary>
/// <remarks>Represents the most specific type known about the object represented by the <see cref="DynamicMetaObject"/>. <see cref="RuntimeType"/> if runtime value is available, a type of the <see cref="Expression"/> otherwise.</remarks>
public Type LimitType {
get {
return RuntimeType ?? Expression.Type;
}
}
/// <summary>
/// Performs the binding of the dynamic conversion operation.
/// </summary>
/// <param name="binder">An instance of the <see cref="ConvertBinder"/> that represents the details of the dynamic operation.</param>
/// <returns>The new <see cref="DynamicMetaObject"/> representing the result of the binding.</returns>
public virtual DynamicMetaObject BindConvert(ConvertBinder binder) {
ContractUtils.RequiresNotNull(binder, "binder");
return binder.FallbackConvert(this);
}
/// <summary>
/// Performs the binding of the dynamic get member operation.
/// </summary>
/// <param name="binder">An instance of the <see cref="GetMemberBinder"/> that represents the details of the dynamic operation.</param>
/// <returns>The new <see cref="DynamicMetaObject"/> representing the result of the binding.</returns>
public virtual DynamicMetaObject BindGetMember(GetMemberBinder binder) {
ContractUtils.RequiresNotNull(binder, "binder");
return binder.FallbackGetMember(this);
}
/// <summary>
/// Performs the binding of the dynamic set member operation.
/// </summary>
/// <param name="binder">An instance of the <see cref="SetMemberBinder"/> that represents the details of the dynamic operation.</param>
/// <param name="value">The <see cref="DynamicMetaObject"/> representing the value for the set member operation.</param>
/// <returns>The new <see cref="DynamicMetaObject"/> representing the result of the binding.</returns>
public virtual DynamicMetaObject BindSetMember(SetMemberBinder binder, DynamicMetaObject value) {
ContractUtils.RequiresNotNull(binder, "binder");
return binder.FallbackSetMember(this, value);
}
/// <summary>
/// Performs the binding of the dynamic delete member operation.
/// </summary>
/// <param name="binder">An instance of the <see cref="DeleteMemberBinder"/> that represents the details of the dynamic operation.</param>
/// <returns>The new <see cref="DynamicMetaObject"/> representing the result of the binding.</returns>
public virtual DynamicMetaObject BindDeleteMember(DeleteMemberBinder binder) {
ContractUtils.RequiresNotNull(binder, "binder");
return binder.FallbackDeleteMember(this);
}
/// <summary>
/// Performs the binding of the dynamic get index operation.
/// </summary>
/// <param name="binder">An instance of the <see cref="GetIndexBinder"/> that represents the details of the dynamic operation.</param>
/// <param name="indexes">An array of <see cref="DynamicMetaObject"/> instances - indexes for the get index operation.</param>
/// <returns>The new <see cref="DynamicMetaObject"/> representing the result of the binding.</returns>
public virtual DynamicMetaObject BindGetIndex(GetIndexBinder binder, DynamicMetaObject[] indexes) {
ContractUtils.RequiresNotNull(binder, "binder");
return binder.FallbackGetIndex(this, indexes);
}
/// <summary>
/// Performs the binding of the dynamic set index operation.
/// </summary>
/// <param name="binder">An instance of the <see cref="SetIndexBinder"/> that represents the details of the dynamic operation.</param>
/// <param name="indexes">An array of <see cref="DynamicMetaObject"/> instances - indexes for the set index operation.</param>
/// <param name="value">The <see cref="DynamicMetaObject"/> representing the value for the set index operation.</param>
/// <returns>The new <see cref="DynamicMetaObject"/> representing the result of the binding.</returns>
public virtual DynamicMetaObject BindSetIndex(SetIndexBinder binder, DynamicMetaObject[] indexes, DynamicMetaObject value) {
ContractUtils.RequiresNotNull(binder, "binder");
return binder.FallbackSetIndex(this, indexes, value);
}
/// <summary>
/// Performs the binding of the dynamic delete index operation.
/// </summary>
/// <param name="binder">An instance of the <see cref="DeleteIndexBinder"/> that represents the details of the dynamic operation.</param>
/// <param name="indexes">An array of <see cref="DynamicMetaObject"/> instances - indexes for the delete index operation.</param>
/// <returns>The new <see cref="DynamicMetaObject"/> representing the result of the binding.</returns>
public virtual DynamicMetaObject BindDeleteIndex(DeleteIndexBinder binder, DynamicMetaObject[] indexes) {
ContractUtils.RequiresNotNull(binder, "binder");
return binder.FallbackDeleteIndex(this, indexes);
}
/// <summary>
/// Performs the binding of the dynamic invoke member operation.
/// </summary>
/// <param name="binder">An instance of the <see cref="InvokeMemberBinder"/> that represents the details of the dynamic operation.</param>
/// <param name="args">An array of <see cref="DynamicMetaObject"/> instances - arguments to the invoke member operation.</param>
/// <returns>The new <see cref="DynamicMetaObject"/> representing the result of the binding.</returns>
public virtual DynamicMetaObject BindInvokeMember(InvokeMemberBinder binder, DynamicMetaObject[] args) {
ContractUtils.RequiresNotNull(binder, "binder");
return binder.FallbackInvokeMember(this, args);
}
/// <summary>
/// Performs the binding of the dynamic invoke operation.
/// </summary>
/// <param name="binder">An instance of the <see cref="InvokeBinder"/> that represents the details of the dynamic operation.</param>
/// <param name="args">An array of <see cref="DynamicMetaObject"/> instances - arguments to the invoke operation.</param>
/// <returns>The new <see cref="DynamicMetaObject"/> representing the result of the binding.</returns>
public virtual DynamicMetaObject BindInvoke(InvokeBinder binder, DynamicMetaObject[] args) {
ContractUtils.RequiresNotNull(binder, "binder");
return binder.FallbackInvoke(this, args);
}
/// <summary>
/// Performs the binding of the dynamic create instance operation.
/// </summary>
/// <param name="binder">An instance of the <see cref="CreateInstanceBinder"/> that represents the details of the dynamic operation.</param>
/// <param name="args">An array of <see cref="DynamicMetaObject"/> instances - arguments to the create instance operation.</param>
/// <returns>The new <see cref="DynamicMetaObject"/> representing the result of the binding.</returns>
public virtual DynamicMetaObject BindCreateInstance(CreateInstanceBinder binder, DynamicMetaObject[] args) {
ContractUtils.RequiresNotNull(binder, "binder");
return binder.FallbackCreateInstance(this, args);
}
/// <summary>
/// Performs the binding of the dynamic unary operation.
/// </summary>
/// <param name="binder">An instance of the <see cref="UnaryOperationBinder"/> that represents the details of the dynamic operation.</param>
/// <returns>The new <see cref="DynamicMetaObject"/> representing the result of the binding.</returns>
public virtual DynamicMetaObject BindUnaryOperation(UnaryOperationBinder binder) {
ContractUtils.RequiresNotNull(binder, "binder");
return binder.FallbackUnaryOperation(this);
}
/// <summary>
/// Performs the binding of the dynamic binary operation.
/// </summary>
/// <param name="binder">An instance of the <see cref="BinaryOperationBinder"/> that represents the details of the dynamic operation.</param>
/// <param name="arg">An instance of the <see cref="DynamicMetaObject"/> representing the right hand side of the binary operation.</param>
/// <returns>The new <see cref="DynamicMetaObject"/> representing the result of the binding.</returns>
public virtual DynamicMetaObject BindBinaryOperation(BinaryOperationBinder binder, DynamicMetaObject arg) {
ContractUtils.RequiresNotNull(binder, "binder");
return binder.FallbackBinaryOperation(this, arg);
}
/// <summary>
/// Returns the enumeration of all dynamic member names.
/// </summary>
/// <returns>The list of dynamic member names.</returns>
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1024:UsePropertiesWhereAppropriate")]
public virtual IEnumerable<string> GetDynamicMemberNames() {
return new string[0];
}
/// <summary>
/// Returns the list of expressions represented by the <see cref="DynamicMetaObject"/> instances.
/// </summary>
/// <param name="objects">An array of <see cref="DynamicMetaObject"/> instances to extract expressions from.</param>
/// <returns>The array of expressions.</returns>
internal static Expression[] GetExpressions(DynamicMetaObject[] objects) {
ContractUtils.RequiresNotNull(objects, "objects");
Expression[] res = new Expression[objects.Length];
for (int i = 0; i < objects.Length; i++) {
DynamicMetaObject mo = objects[i];
ContractUtils.RequiresNotNull(mo, "objects");
Expression expr = mo.Expression;
ContractUtils.RequiresNotNull(expr, "objects");
res[i] = expr;
}
return res;
}
/// <summary>
/// Creates a meta-object for the specified object.
/// </summary>
/// <param name="value">The object to get a meta-object for.</param>
/// <param name="expression">The expression representing this <see cref="DynamicMetaObject"/> during the dynamic binding process.</param>
/// <returns>
/// If the given object implements <see cref="IDynamicMetaObjectProvider"/> and is not a remote object from outside the current AppDomain,
/// returns the object's specific meta-object returned by <see cref="IDynamicMetaObjectProvider.GetMetaObject"/>. Otherwise a plain new meta-object
/// with no restrictions is created and returned.
/// </returns>
public static DynamicMetaObject Create(object value, Expression expression) {
ContractUtils.RequiresNotNull(expression, "expression");
IDynamicMetaObjectProvider ido = value as IDynamicMetaObjectProvider;
#if !SILVERLIGHT
if (ido != null && !RemotingServices.IsObjectOutOfAppDomain(value)) {
#else
if (ido != null) {
#endif
var idoMetaObject = ido.GetMetaObject(expression);
if (idoMetaObject == null ||
!idoMetaObject.HasValue ||
idoMetaObject.Value == null ||
(object)idoMetaObject.Expression != (object)expression) {
throw Error.InvalidMetaObjectCreated(ido.GetType());
}
return idoMetaObject;
} else {
return new DynamicMetaObject(expression, BindingRestrictions.Empty, value);
}
}
}
}
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