osu/osu.Game/Database/RealmExtensions.cs

105 lines
3.9 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 Realms;
namespace osu.Game.Database
{
public static class RealmExtensions
{
/// <summary>
/// Performs a <see cref="Realm.Find{T}(System.Nullable{long})"/>.
/// If a match was not found, a <see cref="Realm.Refresh"/> is performed before trying a second time.
/// This ensures that an instance is found even if the realm requested against was not in a consistent state.
/// </summary>
/// <param name="realm">The realm to operate on.</param>
/// <param name="id">The ID of the entity to find in the realm.</param>
/// <typeparam name="T">The type of the entity to find in the realm.</typeparam>
/// <returns>
/// The retrieved entity of type <typeparamref name="T"/>.
/// Can be <see langword="null"/> if the entity is still not found by <paramref name="id"/> even after a refresh.
/// </returns>
public static T? FindWithRefresh<T>(this Realm realm, Guid id) where T : IRealmObject
{
var found = realm.Find<T>(id);
if (found == null)
{
// It may be that we access this from the update thread before a refresh has taken place.
// To ensure that behaviour matches what we'd expect (the object generally *should be* available), force
// a refresh to bring in any off-thread changes immediately.
realm.Refresh();
found = realm.Find<T>(id);
}
return found;
}
/// <summary>
/// Perform a write operation against the provided realm instance.
/// </summary>
/// <remarks>
/// This will automatically start a transaction if not already in one.
/// </remarks>
/// <param name="realm">The realm to operate on.</param>
/// <param name="function">The write operation to run.</param>
public static void Write(this Realm realm, Action<Realm> function)
{
Transaction? transaction = null;
try
{
if (!realm.IsInTransaction)
transaction = realm.BeginWrite();
function(realm);
transaction?.Commit();
}
finally
{
transaction?.Dispose();
}
}
/// <summary>
/// Perform a write operation against the provided realm instance.
/// </summary>
/// <remarks>
/// This will automatically start a transaction if not already in one.
/// </remarks>
/// <param name="realm">The realm to operate on.</param>
/// <param name="function">The write operation to run.</param>
public static T Write<T>(this Realm realm, Func<Realm, T> function)
{
Transaction? transaction = null;
try
{
if (!realm.IsInTransaction)
transaction = realm.BeginWrite();
var result = function(realm);
transaction?.Commit();
return result;
}
finally
{
transaction?.Dispose();
}
}
/// <summary>
/// Whether the provided change set has changes to the top level collection.
/// </summary>
/// <remarks>
/// Realm subscriptions fire on both collection and property changes (including *all* nested properties).
/// Quite often we only care about changes at a collection level. This can be used to guard and early-return when no such changes are in a callback.
/// </remarks>
public static bool HasCollectionChanges(this ChangeSet changes) => changes.InsertedIndices.Length > 0 || changes.DeletedIndices.Length > 0 || changes.Moves.Length > 0;
}
}