Refine PlayerLoopRunner loop

VContainer/Assets/VContainer/Runtime/Internal/FreeList.cs

@@ -0,0 +1,177 @@
+#nullable enable
+using System;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+
+namespace VContainer.Internal
+{
+    static class UnsafeHelper
+    {
+        public static ref TTo As<TFrom, TTo>(ref TFrom from)
+        {
+#if UNITY_2021_3_OR_NEWER
+            return ref global::Unity.Collections.LowLevel.Unsafe.UnsafeUtility.As<TFrom, TTo>(ref from);
+#else
+            return ref System.Runtime.CompilerServices.Unsafe.As<TFrom, TTo>(ref from);
+#endif
+        }
+    }
+
+    class FreeList<T> where T : class
+    {
+        public bool IsDisposed => lastIndex == -2;
+
+        readonly object gate = new();
+        T?[] values;
+        int lastIndex = -1;
+
+        public FreeList(int initialCapacity)
+        {
+            values = new T[initialCapacity];
+        }
+
+        public ReadOnlySpan<T?> AsSpan()
+        {
+            if (lastIndex < 0)
+            {
+                return ReadOnlySpan<T?>.Empty;
+            }
+            return values.AsSpan(0, lastIndex + 1);
+        }
+
+        public T? this[int index] => values[index];
+
+        public void Add(T item)
+        {
+            lock (gate)
+            {
+                CheckDispose();
+
+                // try find blank
+                var index = FindNullIndex(values);
+                if (index == -1)
+                {
+                    // full, 1, 4, 6,...resize(x1.5)
+                    var len = values.Length;
+                    var newValues = new T[len + len / 2];
+                    Array.Copy(values, newValues, len);
+                    values = newValues;
+                    index = len;
+                }
+
+                values[index] = item;
+                if (lastIndex < index)
+                {
+                    lastIndex = index;
+                }
+            }
+        }
+
+        public void RemoveAt(int index)
+        {
+            lock (gate)
+            {
+                if (index < values.Length)
+                {
+                    ref var v = ref values[index];
+                    if (v == null) throw new KeyNotFoundException($"key index {index} is not found.");
+
+                    v = null;
+                    if (index == lastIndex)
+                    {
+                        lastIndex = FindLastNonNullIndex(values, index);
+                    }
+                }
+            }
+        }
+
+        public bool Remove(T value)
+        {
+            lock (gate)
+            {
+                if (lastIndex < 0) return false;
+
+                var index = -1;
+                var span = values.AsSpan(0, lastIndex + 1);
+                for (var i = 0; i < span.Length; i++)
+                {
+                    if (span[i] == value)
+                    {
+                        index = i;
+                        break;
+                    }
+                }
+
+                if (index != -1)
+                {
+                    RemoveAt(index);
+                    return true;
+                }
+            }
+            return false;
+        }
+
+        public void Clear()
+        {
+            lock (gate)
+            {
+                if (lastIndex > 0)
+                {
+                    values.AsSpan(0, lastIndex + 1).Clear();
+                    lastIndex = -1;
+                }
+            }
+        }
+
+        public void Dispose()
+        {
+            lock (gate)
+            {
+                lastIndex = -2; // -2 is disposed.
+            }
+        }
+
+        void CheckDispose()
+        {
+            if (IsDisposed)
+            {
+                throw new ObjectDisposedException(GetType().FullName);
+            }
+        }
+
+        static unsafe int FindNullIndex(T?[] target)
+        {
+            ref var head = ref UnsafeHelper.As<T?, IntPtr>(ref MemoryMarshal.GetReference(target.AsSpan()));
+            fixed (void* p = &head)
+            {
+                var span = new ReadOnlySpan<IntPtr>(p, target.Length);
+
+#if NETSTANDARD2_1
+                return span.IndexOf(IntPtr.Zero);
+#else
+                for (int i = 0; i < span.Length; i++)
+                {
+                    if (span[i] == IntPtr.Zero) return i;
+                }
+                return -1;
+#endif
+            }
+        }
+
+        static unsafe int FindLastNonNullIndex(T?[] target, int lastIndex)
+        {
+            ref var head = ref UnsafeHelper.As<T?, IntPtr>(ref MemoryMarshal.GetReference(target.AsSpan()));
+            fixed (void* p = &head)
+            {
+                var span = new ReadOnlySpan<IntPtr>(p, lastIndex); // without lastIndexed value.
+
+                for (var i = span.Length - 1; i >= 0; i--)
+                {
+                    if (span[i] != IntPtr.Zero) return i;
+                }
+
+                return -1;
+            }
+        }
+    }
+}

VContainer/Assets/VContainer/Runtime/Unity/PlayerLoopRunner.cs

@@ -1,6 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Threading;
+using VContainer.Internal;
 
 namespace VContainer.Unity
 {
@@ -11,78 +9,30 @@ interface IPlayerLoopItem
 
     sealed class PlayerLoopRunner
     {
-        readonly Queue<IPlayerLoopItem> runningQueue = new Queue<IPlayerLoopItem>();
-        readonly Queue<IPlayerLoopItem> waitingQueue = new Queue<IPlayerLoopItem>();
-
-        readonly object runningGate = new object();
-        readonly object waitingGate = new object();
+        readonly FreeList<IPlayerLoopItem> runners = new FreeList<IPlayerLoopItem>(16);
 
         int running;
 
         public void Dispatch(IPlayerLoopItem item)
         {
-            if (Interlocked.CompareExchange(ref running, 1, 1) == 1)
-            {
-                lock (waitingGate)
-                {
-                    waitingQueue.Enqueue(item);
-                    return;
-                }
-            }
-
-            lock (runningGate)
-            {
-                runningQueue.Enqueue(item);
-            }
+            runners.Add(item);
         }
 
         public void Run()
         {
-            Interlocked.Exchange(ref running, 1);
-
-            lock (runningGate)
-            lock (waitingGate)
-            {
-                while (waitingQueue.Count > 0)
-                {
-                    var waitingItem = waitingQueue.Dequeue();
-                    runningQueue.Enqueue(waitingItem);
-                }
-            }
-
-            IPlayerLoopItem item;
-            lock (runningGate)
-            {
-                item = runningQueue.Count > 0 ? runningQueue.Dequeue() : null;
-            }
-
-            while (item != null)
+            var span = runners.AsSpan();
+            for (var i = 0; i < span.Length; i++)
             {
-                var continuous = false;
-                try
+                var item = span[i];
+                if (item != null)
                 {
-                    continuous = item.MoveNext();
-                }
-                catch (Exception ex)
-                {
-                    UnityEngine.Debug.LogException(ex);
-                }
-
-                if (continuous)
-                {
-                    lock (waitingGate)
+                    var continued = item.MoveNext();
+                    if (!continued)
                     {
-                        waitingQueue.Enqueue(item);
+                        runners.RemoveAt(i);
                     }
                 }
-
-                lock (runningGate)
-                {
-                    item = runningQueue.Count > 0 ? runningQueue.Dequeue() : null;
-                }
             }
-
-            Interlocked.Exchange(ref running, 0);
         }
     }
 }

VContainer/Assets/VContainer/Runtime/VContainer.asmdef

@@ -8,7 +8,7 @@
     ],
     "includePlatforms": [],
     "excludePlatforms": [],
-    "allowUnsafeCode": false,
+    "allowUnsafeCode": true,
     "overrideReferences": false,
     "precompiledReferences": [],
     "autoReferenced": true,
@@ -26,4 +26,4 @@
         }
     ],
     "noEngineReferences": false
-}
+}