Less raw loops.

src/UniTask/Assets/Plugins/UniTask/Runtime/Internal/ArrayUtil.cs

@@ -68,6 +68,55 @@ namespace Cysharp.Threading.Tasks.Internal
                 return (buffer, index);
             }
         }
+        
+        public static void Swap<T>(IList<T> array, int indexA, int indexB)
+        {
+            var tmp = array[indexA];
+            array[indexA] = array[indexB];
+            array[indexB] = tmp;
+        }
+        
+        /// <summary>
+        /// Returns the index of the first element satisfying the <paramref name="predicate"/>.
+        /// Returns -1 if no such element exists.
+        /// </summary>
+        /// <param name="array">The array to search.</param>
+        /// <param name="predicate">The predicate use to search the array.</param>
+        /// <typeparam name="T">The type of elements in the array.</typeparam>
+        /// <returns>Index of the first element satisfying the <paramref name="predicate"/> otherwise returns -1.</returns>
+        public static int FirstIndexOf<T>(IReadOnlyList<T> array, Func<T, bool> predicate)
+        {
+            for (var i = 0; i < array.Count; ++i)
+            {
+                if (!predicate(array[i])) continue;
+                return i;
+            }
+
+            return -1;
+        }
+
+        /// <summary>
+        /// Reorders the elements in <paramref name="array"/> in such a way that all elements for which the <paramref name="predicate"/>
+        /// returns <c>true </c> precede the elements for which <paramref name="predicate"/> returns <c>false</c>.
+        /// Relative order of the elements is not preserved. 
+        /// </summary>
+        /// <param name="array">The array to partition.</param>
+        /// <param name="predicate">The predicate that determine how the elements are partitioned.</param>
+        /// <typeparam name="T">The type of the elements in the array.</typeparam>
+        /// <returns>Return the index of first element of the second group.</returns>
+        public static int Partition<T>(T[] array, Func<T, bool> predicate)
+        {
+            var pivot = FirstIndexOf(array, element => !predicate(element));
+            if (pivot == -1) return array.Length;
+            for (var i = pivot + 1; i < array.Length; ++i)
+            {
+                if (!predicate(array[i])) continue;
+                Swap(array, pivot, i);
+                ++pivot;
+            }
+
+            return pivot;
+        }
     }
 }
 

src/UniTask/Assets/Plugins/UniTask/Runtime/Internal/PlayerLoopRunner.cs

@@ -1,5 +1,4 @@
-
+using System;
-using System;
 using UnityEngine;
 
 namespace Cysharp.Threading.Tasks.Internal
@@ -131,6 +130,7 @@ namespace Cysharp.Threading.Tasks.Internal
         void PostLateUpdate() => RunCore();
         void LastPostLateUpdate() => RunCore();
 
+        
         [System.Diagnostics.DebuggerHidden]
         void RunCore()
         {
@@ -141,84 +141,28 @@ namespace Cysharp.Threading.Tasks.Internal
 
             lock (arrayLock)
             {
-                var j = tail - 1;
+                var pivot = ArrayUtil.Partition(loopItems, playerLoopItem =>
-
-                // eliminate array-bound check for i
-                for (int i = 0; i < loopItems.Length; i++)
                 {
-                    var action = loopItems[i];
+                    try
-                    if (action != null)
+                    {
+                        return playerLoopItem != null && playerLoopItem.MoveNext();
+                    }
+                    catch (Exception e)
                     {
                         try
                         {
-                            if (!action.MoveNext())
+                            unhandledExceptionCallback(e);
-                            {
+                            return false;
-                                loopItems[i] = null;
-                            }
-                            else
-                            {
-                                continue; // next i 
-                            }
                         }
-                        catch (Exception ex)
+                        catch
                         {
-                            loopItems[i] = null;
+                            return false;
-                            try
-                            {
-                                unhandledExceptionCallback(ex);
-                            }
-                            catch { }
                         }
                     }
+                });
                 
-                    // find null, loop from tail
+                for (var i = pivot; i < loopItems.Length; ++i)
-                    while (i < j)
+                    loopItems[i] = null;
-                    {
-                        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)
                 {