// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
#if NET
using System.Runtime.CompilerServices;
#else
using System;
using System.Runtime.InteropServices;
#endif
 
namespace Microsoft.Build.Utilities;
 
/// <summary>
///  Type information for a type <typeparamref name="T"/>.
/// </summary>
internal static partial class TypeInfo<T>
{
    private static bool? s_hasReferences;
 
    /// <summary>
    ///  Returns <see langword="true"/> if the type <typeparamref name="T"/> is a reference type or contains references.
    /// </summary>
    public static bool IsReferenceOrContainsReferences()
    {
#if NET
        return s_hasReferences ??= RuntimeHelpers.IsReferenceOrContainsReferences<T>();
#else
        return s_hasReferences ??= HasReferences();
 
        static bool HasReferences()
        {
            if (!typeof(T).IsValueType)
            {
                return true;
            }
 
            if (typeof(T).IsPrimitive
                || typeof(T).IsEnum
                || typeof(T) == typeof(DateTime))
            {
                return false;
            }
 
            try
            {
                GCHandle handle = GCHandle.Alloc(default(T), GCHandleType.Pinned);
                handle.Free();
                return false;
            }
            catch (Exception)
            {
                // Contained a reference
                return true;
            }
        }
#endif
    }
}