// 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;
 
namespace System.Runtime.CompilerServices
{
    /// <summary>
    /// Holds a reference to a value.
    /// </summary>
    /// <typeparam name="T">The type of the value that the <see cref = "StrongBox{T}"></see> references.</typeparam>
    public class StrongBox<T> : IStrongBox
    {
        /// <summary>
        /// Gets the strongly typed value associated with the <see cref = "StrongBox{T}"></see>
        /// <remarks>This is explicitly exposed as a field instead of a property to enable loading the address of the field.</remarks>
        /// </summary>
        [MaybeNull] public T Value = default!;
 
        /// <summary>
        /// Initializes a new StrongBox which can receive a value when used in a reference call.
        /// </summary>
        public StrongBox()
        {
        }
 
        /// <summary>
        /// Initializes a new <see cref = "StrongBox{T}"></see> with the specified value.
        /// </summary>
        /// <param name="value">A value that the <see cref = "StrongBox{T}"></see> will reference.</param>
        public StrongBox(T value)
        {
            Value = value;
        }
 
        object? IStrongBox.Value
        {
            get => Value;
            set => Value = (T)value!;
        }
    }
 
    /// <summary>
    /// Defines a property for accessing the value that an object references.
    /// </summary>
    public interface IStrongBox
    {
        /// <summary>
        /// Gets or sets the value the object references.
        /// </summary>
        object? Value { get; set; }
    }
}