Unloadable.cs

using System;

namespace OriMod;

/// <summary>
/// Class to handle the unloading of static fields. This class should strictly only be used for static fields.
/// </summary>
internal static class Unloadable {
  /// <summary>
  /// Initialize a static field with the given value, and register an unload action to null the static field.
  /// </summary>
  /// <param name="value">Value to initialize the static field to</param>
  /// <param name="unload">Unload action to set the static field to null</param>
  /// <typeparam name="T">Class type</typeparam>
  /// <returns><paramref name="value"/></returns>
  /// <example>
  /// <code>
  /// public static int[] myArray => _myArray ??=
  ///   Unloadable.New(
  ///     new[] {1, 2, 3, 4},
  ///     () => _myArray = null
  ///   );
  /// private static int[] _myArray;
  /// </code>
  /// </example>
  public static T New<T>(T value, Action unload) where T : class {
    OnUnload += unload;
    return value;
  }

  public static void Unload() {
    OnUnload?.Invoke();
    OnUnload = null;
  }

  public static event Action OnUnload;
}