import from UniRx and some modified.

Assets/UniRx.Async/Internal/PlayerLoopRunner.cs

@@ -0,0 +1,153 @@
+#if CSHARP_7_OR_LATER || (UNITY_2018_3_OR_NEWER && (NET_STANDARD_2_0 || NET_4_6))
+
+using System;
+using UnityEngine;
+
+namespace UniRx.Async.Internal
+{
+    internal sealed class PlayerLoopRunner
+    {
+        const int InitialSize = 16;
+
+        readonly object runningAndQueueLock = new object();
+        readonly object arrayLock = new object();
+        readonly Action<Exception> unhandledExceptionCallback;
+
+        int tail = 0;
+        bool running = false;
+        IPlayerLoopItem[] loopItems = new IPlayerLoopItem[InitialSize];
+        MinimumQueue<IPlayerLoopItem> waitQueue = new MinimumQueue<IPlayerLoopItem>(InitialSize);
+
+        public PlayerLoopRunner()
+        {
+            this.unhandledExceptionCallback = ex => Debug.LogException(ex);
+        }
+
+        public void AddAction(IPlayerLoopItem item)
+        {
+            lock (runningAndQueueLock)
+            {
+                if (running)
+                {
+                    waitQueue.Enqueue(item);
+                    return;
+                }
+            }
+
+            lock (arrayLock)
+            {
+                // Ensure Capacity
+                if (loopItems.Length == tail)
+                {
+                    Array.Resize(ref loopItems, checked(tail * 2));
+                }
+                loopItems[tail++] = item;
+            }
+        }
+
+        public void Run()
+        {
+            lock (runningAndQueueLock)
+            {
+                running = true;
+            }
+
+            lock (arrayLock)
+            {
+                var j = tail - 1;
+
+                // eliminate array-bound check for i
+                for (int i = 0; i < loopItems.Length; i++)
+                {
+                    var action = loopItems[i];
+                    if (action != null)
+                    {
+                        try
+                        {
+                            if (!action.MoveNext())
+                            {
+                                loopItems[i] = null;
+                            }
+                            else
+                            {
+                                continue; // next i 
+                            }
+                        }
+                        catch (Exception ex)
+                        {
+                            loopItems[i] = null;
+                            try
+                            {
+                                unhandledExceptionCallback(ex);
+                            }
+                            catch { }
+                        }
+                    }
+
+                    // find null, loop from tail
+                    while (i < j)
+                    {
+                        var fromTail = loopItems[j];
+                        if (fromTail != null)
+                        {
+                            try
+                            {
+                                if (!fromTail.MoveNext())
+                                {
+                                    loopItems[j] = null;
+                                    j--;
+                                    continue; // next j
+                                }
+                                else
+                                {
+                                    // swap
+                                    loopItems[i] = fromTail;
+                                    loopItems[j] = null;
+                                    j--;
+                                    goto NEXT_LOOP; // next i
+                                }
+                            }
+                            catch (Exception ex)
+                            {
+                                loopItems[j] = null;
+                                j--;
+                                try
+                                {
+                                    unhandledExceptionCallback(ex);
+                                }
+                                catch { }
+                                continue; // next j
+                            }
+                        }
+                        else
+                        {
+                            j--;
+                        }
+                    }
+
+                    tail = i; // loop end
+                    break; // LOOP END
+
+                    NEXT_LOOP:
+                    continue;
+                }
+
+
+                lock (runningAndQueueLock)
+                {
+                    running = false;
+                    while (waitQueue.Count != 0)
+                    {
+                        if (loopItems.Length == tail)
+                        {
+                            Array.Resize(ref loopItems, checked(tail * 2));
+                        }
+                        loopItems[tail++] = waitQueue.Dequeue();
+                    }
+                }
+            }
+        }
+    }
+}
+
+#endif