mirror of https://github.com/ppy/osu
45 lines
1.4 KiB
C#
45 lines
1.4 KiB
C#
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// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
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// See the LICENCE file in the repository root for full licence text.
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#nullable enable
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namespace osu.Game.Utils
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{
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/// <summary>
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/// A wrapper over a value and a boolean denoting whether the value is valid.
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/// </summary>
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/// <typeparam name="T">The type of value stored.</typeparam>
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public readonly ref struct Optional<T>
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{
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/// <summary>
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/// The stored value.
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/// </summary>
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public readonly T Value;
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/// <summary>
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/// Whether <see cref="Value"/> is valid.
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/// </summary>
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/// <remarks>
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/// If <typeparamref name="T"/> is a reference type, <c>null</c> may be valid for <see cref="Value"/>.
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/// </remarks>
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public readonly bool HasValue;
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private Optional(T value)
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{
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Value = value;
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HasValue = true;
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}
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/// <summary>
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/// Returns <see cref="Value"/> if it's valid, or a given fallback value otherwise.
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/// </summary>
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/// <remarks>
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/// Shortcase for: <c>optional.HasValue ? optional.Value : fallback</c>.
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/// </remarks>
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/// <param name="fallback">The fallback value to return if <see cref="HasValue"/> is <c>false</c>.</param>
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public T GetOr(T fallback) => HasValue ? Value : fallback;
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public static implicit operator Optional<T>(T value) => new Optional<T>(value);
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}
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}
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