From a7df20d1201be1859342af02bb855191c6eea674 Mon Sep 17 00:00:00 2001
From: Huy Nguyen <huy@pinterest.com>
Date: Thu, 4 Feb 2016 16:51:21 -0800
Subject: [PATCH] Update range mode selection logic in ASRangeControllerBeta

---
 AsyncDisplayKit/Details/ASLayoutRangeType.h      |  2 ++
 AsyncDisplayKit/Details/ASRangeControllerBeta.mm | 15 +++++----------
 2 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/AsyncDisplayKit/Details/ASLayoutRangeType.h b/AsyncDisplayKit/Details/ASLayoutRangeType.h
index 7be3123533..aed3d98bb9 100644
--- a/AsyncDisplayKit/Details/ASLayoutRangeType.h
+++ b/AsyncDisplayKit/Details/ASLayoutRangeType.h
@@ -29,6 +29,8 @@ typedef NS_ENUM(NSUInteger, ASLayoutRangeMode) {
   ASLayoutRangeModeCount
 };
 
+#define ASLayoutRangeModeInvalid ASLayoutRangeModeCount
+
 typedef NS_ENUM(NSInteger, ASLayoutRangeType) {
   ASLayoutRangeTypeDisplay,
   ASLayoutRangeTypeFetchData,
diff --git a/AsyncDisplayKit/Details/ASRangeControllerBeta.mm b/AsyncDisplayKit/Details/ASRangeControllerBeta.mm
index 3557e00446..82eb877917 100644
--- a/AsyncDisplayKit/Details/ASRangeControllerBeta.mm
+++ b/AsyncDisplayKit/Details/ASRangeControllerBeta.mm
@@ -41,7 +41,7 @@
   }
   
   _rangeIsValid = YES;
-  _currentRangeMode = ASLayoutRangeModeCount;
+  _currentRangeMode = ASLayoutRangeModeInvalid;
   
   return self;
 }
@@ -56,19 +56,15 @@
 #pragma mark - Core visible node range managment API
 
 + (ASLayoutRangeMode)rangeModeForInterfaceState:(ASInterfaceState)interfaceState
-                                scrollDirection:(ASScrollDirection)scrollDirection
                                currentRangeMode:(ASLayoutRangeMode)currentRangeMode
 {
   BOOL isVisible = (ASInterfaceStateIncludesVisible(interfaceState));
-  BOOL isScrolling = (scrollDirection != ASScrollDirectionNone);
-  BOOL isUsingMinimumRangeMode = (currentRangeMode == ASLayoutRangeModeMinimum);
-  // If we are already visible and scrolling, get busy!  Better get started on preloading before the user scrolls more...
-  // If we are already visible and finished displaying minimum mode, extend to full mode
-  if (isVisible && (isScrolling || isUsingMinimumRangeMode)) {
-    return ASLayoutRangeModeFull;
+  BOOL isFirstRangeUpdate = (currentRangeMode == ASLayoutRangeModeInvalid);
+  if (!isVisible || isFirstRangeUpdate) {
+    return ASLayoutRangeModeMinimum;
   }
   
-  return ASLayoutRangeModeMinimum;
+  return ASLayoutRangeModeFull;
 }
 
 - (void)visibleNodeIndexPathsDidChangeWithScrollDirection:(ASScrollDirection)scrollDirection
@@ -282,7 +278,6 @@
 {
   if (!_didRegisterForNotifications) {
     ASLayoutRangeMode nextRangeMode = [ASRangeControllerBeta rangeModeForInterfaceState:interfaceState
-                                                                        scrollDirection:_scrollDirection
                                                                        currentRangeMode:_currentRangeMode];
     if (_currentRangeMode != nextRangeMode) {
       [[NSNotificationCenter defaultCenter] addObserver:self