From 3daacbc2d202b3d42ac84e7242e571a045d8fa09 Mon Sep 17 00:00:00 2001
From: smoogipoo <smoogipoo@smgi.me>
Date: Fri, 17 Apr 2020 13:34:20 +0900
Subject: [PATCH] Initial inefficient refactor of hitobject enumeration

---
 osu.Game.Rulesets.Osu/UI/OrderedHitPolicy.cs | 76 ++++++++------------
 osu.Game.Rulesets.Osu/UI/OsuPlayfield.cs     |  2 +-
 2 files changed, 29 insertions(+), 49 deletions(-)

diff --git a/osu.Game.Rulesets.Osu/UI/OrderedHitPolicy.cs b/osu.Game.Rulesets.Osu/UI/OrderedHitPolicy.cs
index dfca2aff7b..171ce6fe61 100644
--- a/osu.Game.Rulesets.Osu/UI/OrderedHitPolicy.cs
+++ b/osu.Game.Rulesets.Osu/UI/OrderedHitPolicy.cs
@@ -1,9 +1,9 @@
 // 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.Collections.Generic;
 using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Objects.Drawables;
-using osu.Game.Rulesets.Osu.Objects;
 using osu.Game.Rulesets.Osu.Objects.Drawables;
 using osu.Game.Rulesets.UI;
 
@@ -37,12 +37,9 @@ namespace osu.Game.Rulesets.Osu.UI
             DrawableHitObject blockingObject = null;
 
             // Find the last hitobject which blocks future hits.
-            foreach (var obj in hitObjectContainer.AliveObjects)
+            foreach (var obj in enumerateHitObjectsUpTo(hitObject))
             {
-                if (obj == hitObject)
-                    break;
-
-                if (drawableCanBlockFutureHits(obj))
+                if (hitObjectCanBlockFutureHits(obj))
                     blockingObject = obj;
             }
 
@@ -64,64 +61,47 @@ namespace osu.Game.Rulesets.Osu.UI
         /// Handles a <see cref="HitObject"/> being hit to potentially miss all earlier <see cref="HitObject"/>s.
         /// </summary>
         /// <param name="hitObject">The <see cref="HitObject"/> that was hit.</param>
-        public void HandleHit(HitObject hitObject)
+        public void HandleHit(DrawableHitObject hitObject)
         {
             // Hitobjects which themselves don't block future hitobjects don't cause misses (e.g. slider ticks, spinners).
             if (!hitObjectCanBlockFutureHits(hitObject))
                 return;
 
-            double maximumTime = hitObject.StartTime;
-
-            // Iterate through and apply miss results to all top-level and nested hitobjects which block future hits.
-            foreach (var obj in hitObjectContainer.AliveObjects)
+            foreach (var obj in enumerateHitObjectsUpTo(hitObject))
             {
-                if (obj.Judged || obj.HitObject.StartTime >= maximumTime)
+                if (obj.Judged)
                     continue;
 
-                if (hitObjectCanBlockFutureHits(obj.HitObject))
-                    applyMiss(obj);
-
-                foreach (var nested in obj.NestedHitObjects)
-                {
-                    if (nested.Judged || nested.HitObject.StartTime >= maximumTime)
-                        continue;
-
-                    if (hitObjectCanBlockFutureHits(nested.HitObject))
-                        applyMiss(nested);
-                }
+                if (hitObjectCanBlockFutureHits(obj))
+                    ((DrawableOsuHitObject)obj).MissForcefully();
             }
-
-            static void applyMiss(DrawableHitObject obj) => ((DrawableOsuHitObject)obj).MissForcefully();
-        }
-
-        /// <summary>
-        /// Whether a <see cref="DrawableHitObject"/> blocks hits on future <see cref="DrawableHitObject"/>s until its start time is reached.
-        /// </summary>
-        /// <remarks>
-        /// This will ONLY match on top-most <see cref="DrawableHitObject"/>s.
-        /// </remarks>
-        /// <param name="hitObject">The <see cref="DrawableHitObject"/> to test.</param>
-        private static bool drawableCanBlockFutureHits(DrawableHitObject hitObject)
-        {
-            // Special considerations for slider tails aren't required since only top-most drawable hitobjects are being iterated over.
-            return hitObject is DrawableHitCircle || hitObject is DrawableSlider;
         }
 
         /// <summary>
         /// Whether a <see cref="HitObject"/> blocks hits on future <see cref="HitObject"/>s until its start time is reached.
         /// </summary>
-        /// <remarks>
-        /// This is more rigorous and may not match on top-most <see cref="HitObject"/>s as <see cref="drawableCanBlockFutureHits"/> does.
-        /// </remarks>
         /// <param name="hitObject">The <see cref="HitObject"/> to test.</param>
-        private static bool hitObjectCanBlockFutureHits(HitObject hitObject)
-        {
-            // Unlike the above we will receive slider tails, but they do not block future hits.
-            if (hitObject is SliderTailCircle)
-                return false;
+        private static bool hitObjectCanBlockFutureHits(DrawableHitObject hitObject)
+            => hitObject is DrawableHitCircle;
 
-            // All other hitcircles continue to block future hits.
-            return hitObject is HitCircle;
+        // Todo: Inefficient
+        private IEnumerable<DrawableHitObject> enumerateHitObjectsUpTo(DrawableHitObject hitObject)
+        {
+            return enumerate(hitObjectContainer.AliveObjects);
+
+            IEnumerable<DrawableHitObject> enumerate(IEnumerable<DrawableHitObject> list)
+            {
+                foreach (var obj in list)
+                {
+                    if (obj.HitObject.StartTime >= hitObject.HitObject.StartTime)
+                        yield break;
+
+                    yield return obj;
+
+                    foreach (var nested in enumerate(obj.NestedHitObjects))
+                        yield return nested;
+                }
+            }
         }
     }
 }
diff --git a/osu.Game.Rulesets.Osu/UI/OsuPlayfield.cs b/osu.Game.Rulesets.Osu/UI/OsuPlayfield.cs
index 2f222f59b4..4b1a2ce43c 100644
--- a/osu.Game.Rulesets.Osu/UI/OsuPlayfield.cs
+++ b/osu.Game.Rulesets.Osu/UI/OsuPlayfield.cs
@@ -86,7 +86,7 @@ namespace osu.Game.Rulesets.Osu.UI
         private void onNewResult(DrawableHitObject judgedObject, JudgementResult result)
         {
             // Hitobjects that block future hits should miss previous hitobjects if they're hit out-of-order.
-            hitPolicy.HandleHit(result.HitObject);
+            hitPolicy.HandleHit(judgedObject);
 
             if (!judgedObject.DisplayResult || !DisplayJudgements.Value)
                 return;