From 04fa0bff9d8c6bbb2d1b656619a103c7e17d4211 Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Wed, 7 Oct 2020 17:46:57 +0900
Subject: [PATCH] Add CanBeNull spec and xmldoc

---
 osu.Game/Rulesets/Ruleset.cs | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/osu.Game/Rulesets/Ruleset.cs b/osu.Game/Rulesets/Ruleset.cs
index ae1407fb8f..fef36ef16a 100644
--- a/osu.Game/Rulesets/Ruleset.cs
+++ b/osu.Game/Rulesets/Ruleset.cs
@@ -158,8 +158,22 @@ namespace osu.Game.Rulesets
 
         public abstract DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap);
 
+        /// <summary>
+        /// Optionally creates a <see cref="PerformanceCalculator"/> to generate performance data from the provided score.
+        /// </summary>
+        /// <param name="attributes">Difficulty attributes for the beatmap related to the provided score.</param>
+        /// <param name="score">The score to be processed.</param>
+        /// <returns>A performance calculator instance for the provided score.</returns>
+        [CanBeNull]
         public virtual PerformanceCalculator CreatePerformanceCalculator(DifficultyAttributes attributes, ScoreInfo score) => null;
 
+        /// <summary>
+        /// Optionally creates a <see cref="PerformanceCalculator"/> to generate performance data from the provided score.
+        /// </summary>
+        /// <param name="beatmap">The beatmap to use as a source for generating <see cref="DifficultyAttributes"/>.</param>
+        /// <param name="score">The score to be processed.</param>
+        /// <returns>A performance calculator instance for the provided score.</returns>
+        [CanBeNull]
         public PerformanceCalculator CreatePerformanceCalculator(WorkingBeatmap beatmap, ScoreInfo score)
         {
             var difficultyCalculator = CreateDifficultyCalculator(beatmap);