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osu-lazer/osu.Game/Beatmaps/BeatmapDifficultyCache.cs
2020-11-06 13:51:25 +09:00

347 lines
17 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.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using JetBrains.Annotations;
using osu.Framework.Allocation;
using osu.Framework.Bindables;
using osu.Framework.Lists;
using osu.Framework.Logging;
using osu.Framework.Threading;
using osu.Framework.Utils;
using osu.Game.Database;
using osu.Game.Rulesets;
using osu.Game.Rulesets.Mods;
using osu.Game.Rulesets.UI;
namespace osu.Game.Beatmaps
{
/// <summary>
/// A component which performs and acts as a central cache for difficulty calculations of beatmap/ruleset/mod combinations.
/// Currently not persisted between game sessions.
/// </summary>
public class BeatmapDifficultyCache : MemoryCachingComponent<BeatmapDifficultyCache.DifficultyCacheLookup, StarDifficulty>
{
// Too many simultaneous updates can lead to stutters. One thread seems to work fine for song select display purposes.
private readonly ThreadedTaskScheduler updateScheduler = new ThreadedTaskScheduler(1, nameof(BeatmapDifficultyCache));
// All bindables that should be updated along with the current ruleset + mods.
private readonly LockedWeakList<BindableStarDifficulty> trackedBindables = new LockedWeakList<BindableStarDifficulty>();
[Resolved]
private BeatmapManager beatmapManager { get; set; }
[Resolved]
private Bindable<RulesetInfo> currentRuleset { get; set; }
[Resolved]
private Bindable<IReadOnlyList<Mod>> currentMods { get; set; }
protected override void LoadComplete()
{
base.LoadComplete();
currentRuleset.BindValueChanged(_ => updateTrackedBindables());
currentMods.BindValueChanged(_ => updateTrackedBindables(), true);
}
/// <summary>
/// Retrieves a bindable containing the star difficulty of a <see cref="BeatmapInfo"/> that follows the currently-selected ruleset and mods.
/// </summary>
/// <param name="beatmapInfo">The <see cref="BeatmapInfo"/> to get the difficulty of.</param>
/// <param name="cancellationToken">An optional <see cref="CancellationToken"/> which stops updating the star difficulty for the given <see cref="BeatmapInfo"/>.</param>
/// <returns>A bindable that is updated to contain the star difficulty when it becomes available.</returns>
public IBindable<StarDifficulty> GetBindableDifficulty([NotNull] BeatmapInfo beatmapInfo, CancellationToken cancellationToken = default)
{
var bindable = createBindable(beatmapInfo, currentRuleset.Value, currentMods.Value, cancellationToken);
trackedBindables.Add(bindable);
return bindable;
}
/// <summary>
/// Retrieves a bindable containing the star difficulty of a <see cref="BeatmapInfo"/> with a given <see cref="RulesetInfo"/> and <see cref="Mod"/> combination.
/// </summary>
/// <remarks>
/// The bindable will not update to follow the currently-selected ruleset and mods.
/// </remarks>
/// <param name="beatmapInfo">The <see cref="BeatmapInfo"/> to get the difficulty of.</param>
/// <param name="rulesetInfo">The <see cref="RulesetInfo"/> to get the difficulty with. If <c>null</c>, the <paramref name="beatmapInfo"/>'s ruleset is used.</param>
/// <param name="mods">The <see cref="Mod"/>s to get the difficulty with. If <c>null</c>, no mods will be assumed.</param>
/// <param name="cancellationToken">An optional <see cref="CancellationToken"/> which stops updating the star difficulty for the given <see cref="BeatmapInfo"/>.</param>
/// <returns>A bindable that is updated to contain the star difficulty when it becomes available.</returns>
public IBindable<StarDifficulty> GetBindableDifficulty([NotNull] BeatmapInfo beatmapInfo, [CanBeNull] RulesetInfo rulesetInfo, [CanBeNull] IEnumerable<Mod> mods,
CancellationToken cancellationToken = default)
=> createBindable(beatmapInfo, rulesetInfo, mods, cancellationToken);
/// <summary>
/// Retrieves the difficulty of a <see cref="BeatmapInfo"/>.
/// </summary>
/// <param name="beatmapInfo">The <see cref="BeatmapInfo"/> to get the difficulty of.</param>
/// <param name="rulesetInfo">The <see cref="RulesetInfo"/> to get the difficulty with.</param>
/// <param name="mods">The <see cref="Mod"/>s to get the difficulty with.</param>
/// <param name="cancellationToken">An optional <see cref="CancellationToken"/> which stops computing the star difficulty.</param>
/// <returns>The <see cref="StarDifficulty"/>.</returns>
public async Task<StarDifficulty> GetDifficultyAsync([NotNull] BeatmapInfo beatmapInfo, [CanBeNull] RulesetInfo rulesetInfo = null, [CanBeNull] IEnumerable<Mod> mods = null,
CancellationToken cancellationToken = default)
{
if (tryGetExisting(beatmapInfo, rulesetInfo, mods, out var existing, out var key))
return existing;
return await Task.Factory.StartNew(() =>
{
// Computation may have finished in a previous task.
if (tryGetExisting(beatmapInfo, rulesetInfo, mods, out existing, out _))
return existing;
return computeDifficulty(key, beatmapInfo, rulesetInfo);
}, cancellationToken, TaskCreationOptions.HideScheduler | TaskCreationOptions.RunContinuationsAsynchronously, updateScheduler);
}
/// <summary>
/// Retrieves the difficulty of a <see cref="BeatmapInfo"/>.
/// </summary>
/// <param name="beatmapInfo">The <see cref="BeatmapInfo"/> to get the difficulty of.</param>
/// <param name="rulesetInfo">The <see cref="RulesetInfo"/> to get the difficulty with.</param>
/// <param name="mods">The <see cref="Mod"/>s to get the difficulty with.</param>
/// <returns>The <see cref="StarDifficulty"/>.</returns>
public StarDifficulty GetDifficulty([NotNull] BeatmapInfo beatmapInfo, [CanBeNull] RulesetInfo rulesetInfo = null, [CanBeNull] IEnumerable<Mod> mods = null)
{
if (tryGetExisting(beatmapInfo, rulesetInfo, mods, out var existing, out var key))
return existing;
return computeDifficulty(key, beatmapInfo, rulesetInfo);
}
/// <summary>
/// Retrieves the <see cref="DifficultyRating"/> that describes a star rating.
/// </summary>
/// <remarks>
/// For more information, see: https://osu.ppy.sh/help/wiki/Difficulties
/// </remarks>
/// <param name="starRating">The star rating.</param>
/// <returns>The <see cref="DifficultyRating"/> that best describes <paramref name="starRating"/>.</returns>
public static DifficultyRating GetDifficultyRating(double starRating)
{
if (Precision.AlmostBigger(starRating, 6.5, 0.005))
return DifficultyRating.ExpertPlus;
if (Precision.AlmostBigger(starRating, 5.3, 0.005))
return DifficultyRating.Expert;
if (Precision.AlmostBigger(starRating, 4.0, 0.005))
return DifficultyRating.Insane;
if (Precision.AlmostBigger(starRating, 2.7, 0.005))
return DifficultyRating.Hard;
if (Precision.AlmostBigger(starRating, 2.0, 0.005))
return DifficultyRating.Normal;
return DifficultyRating.Easy;
}
private CancellationTokenSource trackedUpdateCancellationSource;
private readonly List<CancellationTokenSource> linkedCancellationSources = new List<CancellationTokenSource>();
/// <summary>
/// Updates all tracked <see cref="BindableStarDifficulty"/> using the current ruleset and mods.
/// </summary>
private void updateTrackedBindables()
{
cancelTrackedBindableUpdate();
trackedUpdateCancellationSource = new CancellationTokenSource();
foreach (var b in trackedBindables)
{
var linkedSource = CancellationTokenSource.CreateLinkedTokenSource(trackedUpdateCancellationSource.Token, b.CancellationToken);
linkedCancellationSources.Add(linkedSource);
updateBindable(b, currentRuleset.Value, currentMods.Value, linkedSource.Token);
}
}
/// <summary>
/// Cancels the existing update of all tracked <see cref="BindableStarDifficulty"/> via <see cref="updateTrackedBindables"/>.
/// </summary>
private void cancelTrackedBindableUpdate()
{
trackedUpdateCancellationSource?.Cancel();
trackedUpdateCancellationSource = null;
if (linkedCancellationSources != null)
{
foreach (var c in linkedCancellationSources)
c.Dispose();
linkedCancellationSources.Clear();
}
}
/// <summary>
/// Creates a new <see cref="BindableStarDifficulty"/> and triggers an initial value update.
/// </summary>
/// <param name="beatmapInfo">The <see cref="BeatmapInfo"/> that star difficulty should correspond to.</param>
/// <param name="initialRulesetInfo">The initial <see cref="RulesetInfo"/> to get the difficulty with.</param>
/// <param name="initialMods">The initial <see cref="Mod"/>s to get the difficulty with.</param>
/// <param name="cancellationToken">An optional <see cref="CancellationToken"/> which stops updating the star difficulty for the given <see cref="BeatmapInfo"/>.</param>
/// <returns>The <see cref="BindableStarDifficulty"/>.</returns>
private BindableStarDifficulty createBindable([NotNull] BeatmapInfo beatmapInfo, [CanBeNull] RulesetInfo initialRulesetInfo, [CanBeNull] IEnumerable<Mod> initialMods,
CancellationToken cancellationToken)
{
var bindable = new BindableStarDifficulty(beatmapInfo, cancellationToken);
updateBindable(bindable, initialRulesetInfo, initialMods, cancellationToken);
return bindable;
}
/// <summary>
/// Updates the value of a <see cref="BindableStarDifficulty"/> with a given ruleset + mods.
/// </summary>
/// <param name="bindable">The <see cref="BindableStarDifficulty"/> to update.</param>
/// <param name="rulesetInfo">The <see cref="RulesetInfo"/> to update with.</param>
/// <param name="mods">The <see cref="Mod"/>s to update with.</param>
/// <param name="cancellationToken">A token that may be used to cancel this update.</param>
private void updateBindable([NotNull] BindableStarDifficulty bindable, [CanBeNull] RulesetInfo rulesetInfo, [CanBeNull] IEnumerable<Mod> mods, CancellationToken cancellationToken = default)
{
GetDifficultyAsync(bindable.Beatmap, rulesetInfo, mods, cancellationToken).ContinueWith(t =>
{
// We're on a threadpool thread, but we should exit back to the update thread so consumers can safely handle value-changed events.
Schedule(() =>
{
if (!cancellationToken.IsCancellationRequested)
bindable.Value = t.Result;
});
}, cancellationToken);
}
/// <summary>
/// Computes the difficulty defined by a <see cref="DifficultyCacheLookup"/> key, and stores it to the timed cache.
/// </summary>
/// <param name="key">The <see cref="DifficultyCacheLookup"/> that defines the computation parameters.</param>
/// <param name="beatmapInfo">The <see cref="BeatmapInfo"/> to compute the difficulty of.</param>
/// <param name="rulesetInfo">The <see cref="RulesetInfo"/> to compute the difficulty with.</param>
/// <returns>The <see cref="StarDifficulty"/>.</returns>
private StarDifficulty computeDifficulty(in DifficultyCacheLookup key, BeatmapInfo beatmapInfo, RulesetInfo rulesetInfo)
{
// In the case that the user hasn't given us a ruleset, use the beatmap's default ruleset.
rulesetInfo ??= beatmapInfo.Ruleset;
try
{
var ruleset = rulesetInfo.CreateInstance();
Debug.Assert(ruleset != null);
var calculator = ruleset.CreateDifficultyCalculator(beatmapManager.GetWorkingBeatmap(beatmapInfo));
var attributes = calculator.Calculate(key.Mods);
return Cache[key] = new StarDifficulty(attributes);
}
catch (BeatmapInvalidForRulesetException e)
{
// Conversion has failed for the given ruleset, so return the difficulty in the beatmap's default ruleset.
// Ensure the beatmap's default ruleset isn't the one already being converted to.
// This shouldn't happen as it means something went seriously wrong, but if it does an endless loop should be avoided.
if (rulesetInfo.Equals(beatmapInfo.Ruleset))
{
Logger.Error(e, $"Failed to convert {beatmapInfo.OnlineBeatmapID} to the beatmap's default ruleset ({beatmapInfo.Ruleset}).");
return Cache[key] = new StarDifficulty();
}
// Check the cache first because this is now a different ruleset than the one previously guarded against.
if (tryGetExisting(beatmapInfo, beatmapInfo.Ruleset, Array.Empty<Mod>(), out var existingDefault, out var existingDefaultKey))
return existingDefault;
return computeDifficulty(existingDefaultKey, beatmapInfo, beatmapInfo.Ruleset);
}
catch
{
return Cache[key] = new StarDifficulty();
}
}
/// <summary>
/// Attempts to retrieve an existing difficulty for the combination.
/// </summary>
/// <param name="beatmapInfo">The <see cref="BeatmapInfo"/>.</param>
/// <param name="rulesetInfo">The <see cref="RulesetInfo"/>.</param>
/// <param name="mods">The <see cref="Mod"/>s.</param>
/// <param name="existingDifficulty">The existing difficulty value, if present.</param>
/// <param name="key">The <see cref="DifficultyCacheLookup"/> key that was used to perform this lookup. This can be further used to query <see cref="computeDifficulty"/>.</param>
/// <returns>Whether an existing difficulty was found.</returns>
private bool tryGetExisting(BeatmapInfo beatmapInfo, RulesetInfo rulesetInfo, IEnumerable<Mod> mods, out StarDifficulty existingDifficulty, out DifficultyCacheLookup key)
{
// In the case that the user hasn't given us a ruleset, use the beatmap's default ruleset.
rulesetInfo ??= beatmapInfo.Ruleset;
// Difficulty can only be computed if the beatmap and ruleset are locally available.
if (beatmapInfo.ID == 0 || rulesetInfo.ID == null)
{
// If not, fall back to the existing star difficulty (e.g. from an online source).
existingDifficulty = new StarDifficulty(beatmapInfo.StarDifficulty, beatmapInfo.MaxCombo ?? 0);
key = default;
return true;
}
key = new DifficultyCacheLookup(beatmapInfo.ID, rulesetInfo.ID.Value, mods);
return Cache.TryGetValue(key, out existingDifficulty);
}
protected override void Dispose(bool isDisposing)
{
base.Dispose(isDisposing);
cancelTrackedBindableUpdate();
updateScheduler?.Dispose();
}
public readonly struct DifficultyCacheLookup : IEquatable<DifficultyCacheLookup>
{
public readonly int BeatmapId;
public readonly int RulesetId;
public readonly Mod[] Mods;
public DifficultyCacheLookup(int beatmapId, int rulesetId, IEnumerable<Mod> mods)
{
BeatmapId = beatmapId;
RulesetId = rulesetId;
Mods = mods?.OrderBy(m => m.Acronym).ToArray() ?? Array.Empty<Mod>();
}
public bool Equals(DifficultyCacheLookup other)
=> BeatmapId == other.BeatmapId
&& RulesetId == other.RulesetId
&& Mods.Select(m => m.Acronym).SequenceEqual(other.Mods.Select(m => m.Acronym));
public override int GetHashCode()
{
var hashCode = new HashCode();
hashCode.Add(BeatmapId);
hashCode.Add(RulesetId);
foreach (var mod in Mods)
hashCode.Add(mod.Acronym);
return hashCode.ToHashCode();
}
}
private class BindableStarDifficulty : Bindable<StarDifficulty>
{
public readonly BeatmapInfo Beatmap;
public readonly CancellationToken CancellationToken;
public BindableStarDifficulty(BeatmapInfo beatmap, CancellationToken cancellationToken)
{
Beatmap = beatmap;
CancellationToken = cancellationToken;
}
}
}
}