From 94076dc9be145733f08e3bb35fad9beb9544b5d1 Mon Sep 17 00:00:00 2001
From: Ske <voltasalt@gmail.com>
Date: Wed, 22 Jul 2020 01:19:23 +0200
Subject: [PATCH] Split HandlerQueue logic into Predicate/Handler

---
 PluralKit.Core/Utils/HandlerQueue.cs | 23 ++++++++---------------
 1 file changed, 8 insertions(+), 15 deletions(-)

diff --git a/PluralKit.Core/Utils/HandlerQueue.cs b/PluralKit.Core/Utils/HandlerQueue.cs
index b8347bbb..9d261c0a 100644
--- a/PluralKit.Core/Utils/HandlerQueue.cs
+++ b/PluralKit.Core/Utils/HandlerQueue.cs
@@ -12,27 +12,18 @@ namespace PluralKit.Core
         private long _seq;
         private readonly ConcurrentDictionary<long, HandlerEntry> _handlers = new ConcurrentDictionary<long, HandlerEntry>();
 
-        public HandlerEntry Add(Func<T, Task<bool>> handler)
-        {
-            var entry = new HandlerEntry {Handler = handler};
-
-            _handlers[Interlocked.Increment(ref _seq)] = entry;
-            return entry;
-        }
-
         public async Task<T> WaitFor(Func<T, bool> predicate, Duration? timeout = null, CancellationToken ct = default)
         {
             var timeoutTask = Task.Delay(timeout?.ToTimeSpan() ?? TimeSpan.FromMilliseconds(-1), ct);
             var tcs = new TaskCompletionSource<T>();
 
-            Task<bool> Handler(T e)
+            ValueTask Handler(T e)
             {
-                var matches = predicate(e);
-                if (matches) tcs.SetResult(e);
-                return Task.FromResult(matches);
+                tcs.SetResult(e);
+                return default;
             }
 
-            var entry = new HandlerEntry {Handler = Handler};
+            var entry = new HandlerEntry {Predicate = predicate, Handler = Handler};
             _handlers[Interlocked.Increment(ref _seq)] = entry;
 
             // Wait for either the event task or the timeout task
@@ -63,8 +54,9 @@ namespace PluralKit.Core
             foreach (var (_, entry) in _handlers)
             {
                 if (entry.Expiry < now) entry.Alive = false;
-                else if (entry.Alive && await entry.Handler(evt))
+                else if (entry.Alive && entry.Predicate(evt))
                 {
+                    await entry.Handler(evt);
                     entry.Alive = false;
                     return true;
                 }
@@ -75,7 +67,8 @@ namespace PluralKit.Core
 
         public class HandlerEntry
         {
-            internal Func<T, Task<bool>> Handler;
+            internal Func<T, ValueTask> Handler;
+            internal Func<T, bool> Predicate;
             internal bool Alive = true;
             internal Instant Expiry = SystemClock.Instance.GetCurrentInstant() + Duration.FromMinutes(30);