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osu-lazer/osu.Game/Database/RealmLive.cs
Dean Herbert 93d7cdc509 Don't check whether the source realm was closed or not
Based on what we now know, this is not required, as long as there is
another realm context open on the same thread.
2021-10-13 15:50:06 +09:00

112 lines
3.7 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.
using System;
using System.Threading;
using Realms;
#nullable enable
namespace osu.Game.Database
{
/// <summary>
/// Provides a method of working with realm objects over longer application lifetimes.
/// </summary>
/// <typeparam name="T">The underlying object type.</typeparam>
public class RealmLive<T> : ILive<T> where T : RealmObject, IHasGuidPrimaryKey
{
public Guid ID { get; }
private readonly SynchronizationContext? fetchedContext;
private readonly int fetchedThreadId;
/// <summary>
/// The original live data used to create this instance.
/// </summary>
private readonly T data;
/// <summary>
/// Construct a new instance of live realm data.
/// </summary>
/// <param name="data">The realm data.</param>
public RealmLive(T data)
{
this.data = data;
fetchedContext = SynchronizationContext.Current;
fetchedThreadId = Thread.CurrentThread.ManagedThreadId;
ID = data.ID;
}
/// <summary>
/// Perform a read operation on this live object.
/// </summary>
/// <param name="perform">The action to perform.</param>
public void PerformRead(Action<T> perform)
{
if (originalDataValid)
{
perform(data);
return;
}
using (var realm = Realm.GetInstance(data.Realm.Config))
perform(realm.Find<T>(ID));
}
/// <summary>
/// Perform a read operation on this live object.
/// </summary>
/// <param name="perform">The action to perform.</param>
public TReturn PerformRead<TReturn>(Func<T, TReturn> perform)
{
if (typeof(RealmObjectBase).IsAssignableFrom(typeof(TReturn)))
throw new InvalidOperationException($"Realm live objects should not exit the scope of {nameof(PerformRead)}.");
if (originalDataValid)
return perform(data);
using (var realm = Realm.GetInstance(data.Realm.Config))
return perform(realm.Find<T>(ID));
}
/// <summary>
/// Perform a write operation on this live object.
/// </summary>
/// <param name="perform">The action to perform.</param>
public void PerformWrite(Action<T> perform) =>
PerformRead(t =>
{
var transaction = t.Realm.BeginWrite();
perform(t);
transaction.Commit();
});
public T Value
{
get
{
if (originalDataValid)
return data;
T retrieved;
using (var realm = Realm.GetInstance(data.Realm.Config))
retrieved = realm.Find<T>(ID);
if (!retrieved.IsValid)
throw new InvalidOperationException("Attempted to access value without an open context");
return retrieved;
}
}
private bool originalDataValid => isCorrectThread && data.IsValid;
// this matches realm's internal thread validation (see https://github.com/realm/realm-dotnet/blob/903b4d0b304f887e37e2d905384fb572a6496e70/Realm/Realm/Native/SynchronizationContextScheduler.cs#L72)
private bool isCorrectThread
=> (fetchedContext != null && SynchronizationContext.Current == fetchedContext) || fetchedThreadId == Thread.CurrentThread.ManagedThreadId;
}
}