// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
namespace System;
 
/// <summary>
///  Helper to allow using new patterns for throwing <see cref="ArgumentNullException"/>s.
/// </summary>
internal static class ArgumentNullExtensions
{
    extension(ArgumentNullException)
    {
        /// <summary>Throws an <see cref="ArgumentNullException"/> if <paramref name="argument"/> is null.</summary>
        /// <param name="argument">The reference type argument to validate as non-null.</param>
        /// <param name="paramName">The name of the parameter with which <paramref name="argument"/> corresponds.</param>
        public static void ThrowIfNull([NotNull] object? argument, [CallerArgumentExpression(nameof(argument))] string? paramName = null)
        {
            if (argument is null)
            {
                Throw(paramName);
            }
        }
 
        /// <summary>Throws an <see cref="ArgumentNullException"/> if <paramref name="argument"/> is null.</summary>
        /// <param name="argument">The pointer argument to validate as non-null.</param>
        /// <param name="paramName">The name of the parameter with which <paramref name="argument"/> corresponds.</param>
        public static unsafe void ThrowIfNull([NotNull] void* argument, [CallerArgumentExpression(nameof(argument))] string? paramName = null)
        {
            if (argument is null)
            {
                Throw(paramName);
            }
        }
 
        /// <summary>Throws an <see cref="ArgumentNullException"/> if <paramref name="argument"/> is null.</summary>
        /// <param name="argument">The pointer argument to validate as non-null.</param>
        /// <param name="paramName">The name of the parameter with which <paramref name="argument"/> corresponds.</param>
        public static void ThrowIfNull(IntPtr argument, [CallerArgumentExpression(nameof(argument))] string? paramName = null)
        {
            if (argument == IntPtr.Zero)
            {
                Throw(paramName);
            }
        }
    }
 
#pragma warning disable IDE0051 // Remove unused private members
    // .NET Framework analyzers don't understand that this method is only called from the extension methods above,
    // so it thinks it's unused. Suppress that warning since this method is actually used.
 
    [DoesNotReturn]
    private static void Throw(string? paramName) => throw new ArgumentNullException(paramName);
#pragma warning restore IDE0051
}