From ec19b928a8b4cee7e12798e2ada629611a3b4a5f Mon Sep 17 00:00:00 2001
From: Huy Nguyen <huy@pinterest.com>
Date: Tue, 6 Oct 2020 11:42:37 -0700
Subject: [PATCH] Ship ASExperimentalDispatchApply (#1924)

Closes #1850.
---
 Source/Private/ASDispatch.h  |  2 +-
 Source/Private/ASDispatch.mm | 40 +++++++++++-------------------------
 2 files changed, 13 insertions(+), 29 deletions(-)

diff --git a/Source/Private/ASDispatch.h b/Source/Private/ASDispatch.h
index caccf74de..6ef5a8c96 100644
--- a/Source/Private/ASDispatch.h
+++ b/Source/Private/ASDispatch.h
@@ -11,7 +11,7 @@
 #import <AsyncDisplayKit/ASBaseDefines.h>
 
 /**
- * Like dispatch_apply, but you can set the thread count. 0 means 2*active CPUs.
+ * Like dispatch_apply, but you can set the thread count. 0 means letting dispatch_apply determine it.
  *
  * Note: The actual number of threads may be lower than threadCount, if libdispatch
  * decides the system can't handle it. In reality this rarely happens.
diff --git a/Source/Private/ASDispatch.mm b/Source/Private/ASDispatch.mm
index 769a9185d..b82032da7 100644
--- a/Source/Private/ASDispatch.mm
+++ b/Source/Private/ASDispatch.mm
@@ -9,43 +9,27 @@
 #import <AsyncDisplayKit/ASDispatch.h>
 #import <AsyncDisplayKit/ASConfigurationInternal.h>
 
-
 // Prefer C atomics in this file because ObjC blocks can't capture C++ atomics well.
 #import <stdatomic.h>
 
-/**
- * Like dispatch_apply, but you can set the thread count. 0 means 2*active CPUs.
- *
- * Note: The actual number of threads may be lower than threadCount, if libdispatch
- * decides the system can't handle it. In reality this rarely happens.
- */
 void ASDispatchApply(size_t iterationCount, dispatch_queue_t queue, NSUInteger threadCount, NS_NOESCAPE void(^work)(size_t i)) {
   if (threadCount == 0) {
-    if (ASActivateExperimentalFeature(ASExperimentalDispatchApply)) {
-      dispatch_apply(iterationCount, queue, work);
-      return;
+    dispatch_apply(iterationCount, queue, work);
+  } else {
+    dispatch_group_t group = dispatch_group_create();
+    __block atomic_size_t counter = ATOMIC_VAR_INIT(0);
+    for (NSUInteger t = 0; t < threadCount; t++) {
+      dispatch_group_async(group, queue, ^{
+        size_t i;
+        while ((i = atomic_fetch_add(&counter, 1)) < iterationCount) {
+          work(i);
+        }
+      });
     }
-    threadCount = NSProcessInfo.processInfo.activeProcessorCount * 2;
-  }
-  dispatch_group_t group = dispatch_group_create();
-  __block atomic_size_t counter = ATOMIC_VAR_INIT(0);
-  for (NSUInteger t = 0; t < threadCount; t++) {
-    dispatch_group_async(group, queue, ^{
-      size_t i;
-      while ((i = atomic_fetch_add(&counter, 1)) < iterationCount) {
-        work(i);
-      }
-    });
+    dispatch_group_wait(group, DISPATCH_TIME_FOREVER);
   }
-  dispatch_group_wait(group, DISPATCH_TIME_FOREVER);
 };
 
-/**
- * Like dispatch_async, but you can set the thread count. 0 means 2*active CPUs.
- *
- * Note: The actual number of threads may be lower than threadCount, if libdispatch
- * decides the system can't handle it. In reality this rarely happens.
- */
 void ASDispatchAsync(size_t iterationCount, dispatch_queue_t queue, NSUInteger threadCount, NS_NOESCAPE void(^work)(size_t i)) {
   if (threadCount == 0) {
     threadCount = NSProcessInfo.processInfo.activeProcessorCount * 2;