// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Runtime.CompilerServices;
 
namespace System.Windows.Markup
{
    /// <summary>
    /// Can be specified on a collection type to indicate which
    /// types are used to wrap content foreign content such as
    /// strings in a strongly type Collection.
    /// </summary>
    [AttributeUsage(AttributeTargets.Class, AllowMultiple = true, Inherited = true)]
    [TypeForwardedFrom("WindowsBase, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35")]
    public sealed class ContentWrapperAttribute : Attribute
    {
        /// <summary>
        /// Declares the given type as being a content wrapper for the collection
        /// type this attribute is declared on.
        /// </summary>
        /// <param name="contentWrapper"></param>
        public ContentWrapperAttribute(Type? contentWrapper)
        {
            ContentWrapper = contentWrapper;
        }
 
        /// <summary>
        /// The type that is declared as a content wrapper for the collection type
        /// this attribute is declared on.
        /// </summary>
        public Type? ContentWrapper { get; }
 
        /// <summary>
        /// Override to ensure AttributeCollection perserves all instances
        /// </summary>
        public override object TypeId => this;
 
        /// <summary>
        /// Overrides Object.Equals to implement correct equality semantics for this
        /// attribute.
        /// </summary>
        public override bool Equals(object? obj)
        {
            return
                obj is ContentWrapperAttribute other &&
                ContentWrapper == other.ContentWrapper;
        }
 
        /// <summary>
        /// Overrides Object.GetHashCode to implement correct hashing semantics.
        /// </summary>
        public override int GetHashCode() => ContentWrapper?.GetHashCode() ?? 0;
    }
}