osu/osu.Game/Rulesets/Objects/HitObjectProperty.cs

53 lines
1.7 KiB
C#

// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
// See the LICENCE file in the repository root for full licence text.
#nullable disable
using JetBrains.Annotations;
using osu.Framework.Bindables;
namespace osu.Game.Rulesets.Objects
{
/// <summary>
/// Represents a wrapper containing a lazily-initialised <see cref="Bindable{T}"/>, backed by a temporary field used for <see cref="Value"/> storage until initialisation.
/// </summary>
public struct HitObjectProperty<T>
{
[CanBeNull]
private Bindable<T> backingBindable;
/// <summary>
/// A temporary field to store the current value to, prior to <see cref="Bindable"/>'s initialisation.
/// </summary>
private T backingValue;
/// <summary>
/// The underlying <see cref="Bindable{T}"/>, only initialised on first access.
/// </summary>
public Bindable<T> Bindable => backingBindable ??= new Bindable<T>(defaultValue) { Value = backingValue };
/// <summary>
/// The current value, derived from and delegated to <see cref="Bindable"/> if initialised, or a temporary field otherwise.
/// </summary>
public T Value
{
get => backingBindable != null ? backingBindable.Value : backingValue;
set
{
if (backingBindable != null)
backingBindable.Value = value;
else
backingValue = value;
}
}
private readonly T defaultValue;
public HitObjectProperty(T value = default)
{
backingValue = defaultValue = value;
backingBindable = null;
}
}
}