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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Diagnostics.CodeAnalysis;
using System.Dynamic.Utils;
using System.Linq.Expressions;
namespace System.Dynamic
{
/// <summary>
/// Represents the create dynamic operation at the call site, providing the binding semantic and the details about the operation.
/// </summary>
[RequiresDynamicCode(Expression.CallSiteRequiresDynamicCode)]
public abstract class CreateInstanceBinder : DynamicMetaObjectBinder
{
/// <summary>
/// Initializes a new instance of the <see cref="CreateInstanceBinder" />.
/// </summary>
/// <param name="callInfo">The signature of the arguments at the call site.</param>
protected CreateInstanceBinder(CallInfo callInfo)
{
ArgumentNullException.ThrowIfNull(callInfo);
CallInfo = callInfo;
}
/// <summary>
/// The result type of the operation.
/// </summary>
public sealed override Type ReturnType => typeof(object);
/// <summary>
/// Gets the signature of the arguments at the call site.
/// </summary>
public CallInfo CallInfo { get; }
/// <summary>
/// Performs the binding of the dynamic create operation if the target dynamic object cannot bind.
/// </summary>
/// <param name="target">The target of the dynamic create operation.</param>
/// <param name="args">The arguments of the dynamic create operation.</param>
/// <returns>The <see cref="DynamicMetaObject"/> representing the result of the binding.</returns>
public DynamicMetaObject FallbackCreateInstance(DynamicMetaObject target, DynamicMetaObject[] args)
{
return FallbackCreateInstance(target, args, null);
}
/// <summary>
/// When overridden in the derived class, performs the binding of the dynamic create operation if the target dynamic object cannot bind.
/// </summary>
/// <param name="target">The target of the dynamic create operation.</param>
/// <param name="args">The arguments of the dynamic create operation.</param>
/// <param name="errorSuggestion">The binding result to use if binding fails, or null.</param>
/// <returns>The <see cref="DynamicMetaObject"/> representing the result of the binding.</returns>
public abstract DynamicMetaObject FallbackCreateInstance(DynamicMetaObject target, DynamicMetaObject[] args, DynamicMetaObject? errorSuggestion);
/// <summary>
/// Performs the binding of the dynamic create operation.
/// </summary>
/// <param name="target">The target of the dynamic create operation.</param>
/// <param name="args">An array of arguments of the dynamic create operation.</param>
/// <returns>The <see cref="DynamicMetaObject"/> representing the result of the binding.</returns>
public sealed override DynamicMetaObject Bind(DynamicMetaObject target, DynamicMetaObject[] args)
{
ArgumentNullException.ThrowIfNull(target);
ContractUtils.RequiresNotNullItems(args, nameof(args));
return target.BindCreateInstance(this, args);
}
/// <summary>
/// Always returns <c>true</c> because this is a standard <see cref="DynamicMetaObjectBinder"/>.
/// </summary>
internal sealed override bool IsStandardBinder => true;
}
}
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