From bb110ca6e8c1ba1fb2fd42e2dbe33902868e6305 Mon Sep 17 00:00:00 2001
From: Michael Schneider <mischneider1@gmail.com>
Date: Fri, 8 Apr 2016 20:02:20 -0700
Subject: [PATCH] Readd ASDisplayShouldFetchBatchForContext

---
 AsyncDisplayKit/Private/ASBatchFetching.h | 20 ++++++++++++++++++++
 AsyncDisplayKit/Private/ASBatchFetching.m | 16 ++++++++++++----
 2 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/AsyncDisplayKit/Private/ASBatchFetching.h b/AsyncDisplayKit/Private/ASBatchFetching.h
index 6b0c1be595..094a2c6c5d 100644
--- a/AsyncDisplayKit/Private/ASBatchFetching.h
+++ b/AsyncDisplayKit/Private/ASBatchFetching.h
@@ -32,4 +32,24 @@ ASDISPLAYNODE_EXTERN_C_BEGIN
  */
 BOOL ASDisplayShouldFetchBatchForScrollView(UIScrollView<ASBatchFetchingScrollView> *scrollView, ASScrollDirection scrollDirection, CGPoint contentOffset);
 
+
+/**
+ @abstract Determine if batch fetching should begin based on the state of the parameters.
+ @param context The batch fetching context that contains knowledge about in-flight fetches.
+ @param scrollDirection The current scrolling direction of the scroll view.
+ @param bounds The bounds of the scrollview.
+ @param contentSize The content size of the scrollview.
+ @param targetOffset The offset that the scrollview will scroll to.
+ @param leadingScreens How many screens in the remaining distance will trigger batch fetching.
+ @return Whether or not the current state should proceed with batch fetching.
+ @discussion This method is broken into a category for unit testing purposes and should be used with the ASTableView and
+ * ASCollectionView batch fetching API.
+ */
+extern BOOL ASDisplayShouldFetchBatchForContext(ASBatchContext *context,
+                                                ASScrollDirection scrollDirection,
+                                                CGRect bounds,
+                                                CGSize contentSize,
+                                                CGPoint targetOffset,
+                                                CGFloat leadingScreens);
+
 ASDISPLAYNODE_EXTERN_C_END
diff --git a/AsyncDisplayKit/Private/ASBatchFetching.m b/AsyncDisplayKit/Private/ASBatchFetching.m
index 9158c30b84..6a8d9fc10d 100644
--- a/AsyncDisplayKit/Private/ASBatchFetching.m
+++ b/AsyncDisplayKit/Private/ASBatchFetching.m
@@ -10,7 +10,6 @@
 
 BOOL ASDisplayShouldFetchBatchForScrollView(UIScrollView<ASBatchFetchingScrollView> *scrollView, ASScrollDirection scrollDirection, CGPoint contentOffset)
 {
-
   // Don't fetch if the scroll view does not allow
   if (![scrollView canBatchFetch]) {
     return NO;
@@ -21,7 +20,16 @@ BOOL ASDisplayShouldFetchBatchForScrollView(UIScrollView<ASBatchFetchingScrollVi
   CGRect bounds = scrollView.bounds;
   CGSize contentSize = scrollView.contentSize;
   CGFloat leadingScreens = scrollView.leadingScreensForBatching;
-  
+  return ASDisplayShouldFetchBatchForContext(context, scrollDirection, bounds, contentSize, contentOffset, leadingScreens);
+}
+
+BOOL ASDisplayShouldFetchBatchForContext(ASBatchContext *context,
+                                         ASScrollDirection scrollDirection,
+                                         CGRect bounds,
+                                         CGSize contentSize,
+                                         CGPoint targetOffset,
+                                         CGFloat leadingScreens)
+{
   // Do not allow fetching if a batch is already in-flight and hasn't been completed or cancelled
   if ([context isFetching]) {
     return NO;
@@ -41,11 +49,11 @@ BOOL ASDisplayShouldFetchBatchForScrollView(UIScrollView<ASBatchFetchingScrollVi
 
   if (ASScrollDirectionContainsDown(scrollDirection)) {
     viewLength = bounds.size.height;
-    offset = contentOffset.y;
+    offset = targetOffset.y;
     contentLength = contentSize.height;
   } else { // horizontal / right
     viewLength = bounds.size.width;
-    offset = contentOffset.x;
+    offset = targetOffset.x;
     contentLength = contentSize.width;
   }