osu/osu.Game/Database/Live.cs

67 lines
2.2 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.
using System;
using JetBrains.Annotations;
namespace osu.Game.Database
{
/// <summary>
/// A wrapper to provide access to database backed classes in a thread-safe manner.
/// </summary>
/// <typeparam name="T">The databased type.</typeparam>
public abstract class Live<T> : IEquatable<Live<T>>
where T : class, IHasGuidPrimaryKey
{
public Guid ID { get; }
/// <summary>
/// Perform a read operation on this live object.
/// </summary>
/// <param name="perform">The action to perform.</param>
public abstract void PerformRead([InstantHandle] Action<T> perform);
/// <summary>
/// Perform a read operation on this live object.
/// </summary>
/// <param name="perform">The action to perform.</param>
public abstract TReturn PerformRead<TReturn>([InstantHandle] Func<T, TReturn> perform);
/// <summary>
/// Perform a write operation on this live object.
/// </summary>
/// <param name="perform">The action to perform.</param>
public abstract void PerformWrite([InstantHandle] Action<T> perform);
/// <summary>
/// Whether this instance is tracking data which is managed by the database backing.
/// </summary>
public abstract bool IsManaged { get; }
/// <summary>
/// Resolve the value of this instance on the update thread.
/// </summary>
/// <remarks>
/// After resolving, the data should not be passed between threads.
/// </remarks>
public abstract T Value { get; }
protected Live(Guid id)
{
ID = id;
}
public bool Equals(Live<T>? other)
{
if (ReferenceEquals(this, other)) return true;
if (other == null) return false;
return ID == other.ID;
}
public override int GetHashCode() => HashCode.Combine(ID);
public override string ToString() => PerformRead(i => i.ToString());
}
}