From 4f9c61a37f088eed5b037ffbb79a47fe58c96989 Mon Sep 17 00:00:00 2001
From: Maxime Ollivier <maxo@instagram.com>
Date: Tue, 30 Apr 2019 10:44:00 -0700
Subject: [PATCH] clean up IGListExperimentBackgroundDiffingSerial

Summary: * Cleaning up experiment

Reviewed By: lorixx

Differential Revision: D15134137

fbshipit-source-id: a3f5a6d7b4a5f3897608c4e32ad4c4e6e4e720e5
---
 Source/Common/IGListExperiments.h              |  2 --
 Source/IGListAdapterUpdater.m                  | 11 +----------
 Source/Internal/IGListAdapterUpdaterInternal.h |  2 --
 3 files changed, 1 insertion(+), 14 deletions(-)

diff --git a/Source/Common/IGListExperiments.h b/Source/Common/IGListExperiments.h
index 0f243327..30048f33 100644
--- a/Source/Common/IGListExperiments.h
+++ b/Source/Common/IGListExperiments.h
@@ -26,8 +26,6 @@ typedef NS_OPTIONS (NSInteger, IGListExperiment) {
     IGListExperimentGetCollectionViewAtUpdate = 1 << 7,
     /// Test skipping layout when UICollectionView isn't visible
     IGListExperimentSkipLayout = 1 << 8,
-    /// Test updater diffing performed on a serial background queue.
-    IGListExperimentBackgroundDiffingSerial = 1 << 9,
 };
 
 /**
diff --git a/Source/IGListAdapterUpdater.m b/Source/IGListAdapterUpdater.m
index 21a8b3f8..71eb84e0 100644
--- a/Source/IGListAdapterUpdater.m
+++ b/Source/IGListAdapterUpdater.m
@@ -265,17 +265,8 @@ willPerformBatchUpdatesWithCollectionView:collectionView
         }
     };
 
-    dispatch_queue_t asyncQueue = nil;
     if (IGListExperimentEnabled(experiments, IGListExperimentBackgroundDiffing)) {
-        asyncQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
-    } else if (IGListExperimentEnabled(experiments, IGListExperimentBackgroundDiffingSerial)) {
-        if (_backgroundUpdateQueue == nil) {
-            _backgroundUpdateQueue = dispatch_queue_create("io.github.instagram.IGListKit.backgroundupdatequeue", DISPATCH_QUEUE_SERIAL);
-        }
-        asyncQueue = _backgroundUpdateQueue;
-    }
-    if (asyncQueue) {
-        dispatch_async(asyncQueue, ^{
+        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
             IGListIndexSetResult *result = performDiff();
             dispatch_async(dispatch_get_main_queue(), ^{
                 performUpdate(result);
diff --git a/Source/Internal/IGListAdapterUpdaterInternal.h b/Source/Internal/IGListAdapterUpdaterInternal.h
index 40c8ef52..b794608b 100644
--- a/Source/Internal/IGListAdapterUpdaterInternal.h
+++ b/Source/Internal/IGListAdapterUpdaterInternal.h
@@ -41,8 +41,6 @@ FOUNDATION_EXTERN void convertReloadToDeleteInsert(NSMutableIndexSet *reloads,
 @property (nonatomic, assign) IGListBatchUpdateState state;
 @property (nonatomic, strong, nullable) IGListBatchUpdateData *applyingUpdateData;
 
-@property (nonatomic, strong) dispatch_queue_t backgroundUpdateQueue;
-
 - (void)performReloadDataWithCollectionViewBlock:(IGListCollectionViewBlock)collectionViewBlock;
 - (void)performBatchUpdatesWithCollectionViewBlock:(IGListCollectionViewBlock)collectionViewBlock;
 - (void)cleanStateBeforeUpdates;