From 9e3856fd99ee150e4e51741e9f1d3df970a8d3a1 Mon Sep 17 00:00:00 2001
From: Valentin Shergin <shergin@fb.com>
Date: Fri, 10 May 2019 15:31:00 -0700
Subject: [PATCH] Fabric: Fixed threading issues in RCTSurfacePresenter

Summary: RCTComponentViewRegistry is not a thread-safe class and must be accessed only from the main thread.

Reviewed By: JoshuaGross

Differential Revision: D15296475

fbshipit-source-id: 67192abd6290191f3b8119972efc41cec48a793a
---
 React/Fabric/RCTSurfacePresenter.mm | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/React/Fabric/RCTSurfacePresenter.mm b/React/Fabric/RCTSurfacePresenter.mm
index 15a0f40ad8e..1bf3ae3d93a 100644
--- a/React/Fabric/RCTSurfacePresenter.mm
+++ b/React/Fabric/RCTSurfacePresenter.mm
@@ -250,8 +250,11 @@ using namespace facebook::react;
 
 - (void)_startSurface:(RCTFabricSurface *)surface
 {
-  [_mountingManager.componentViewRegistry dequeueComponentViewWithComponentHandle:RootShadowNode::Handle()
-                                                                              tag:surface.rootTag];
+  RCTMountingManager *mountingManager = _mountingManager;
+  RCTExecuteOnMainQueue(^{
+    [mountingManager.componentViewRegistry dequeueComponentViewWithComponentHandle:RootShadowNode::Handle()
+                                                                               tag:surface.rootTag];
+  });
 
   LayoutContext layoutContext = {
     .pointScaleFactor = RCTScreenScale()
@@ -273,11 +276,14 @@ using namespace facebook::react;
 {
   [self._scheduler stopSurfaceWithSurfaceId:surface.rootTag];
 
-  UIView<RCTComponentViewProtocol> *rootView =
-    [_mountingManager.componentViewRegistry componentViewByTag:surface.rootTag];
-  [_mountingManager.componentViewRegistry enqueueComponentViewWithComponentHandle:RootShadowNode::Handle()
-                                                                              tag:surface.rootTag
-                                                                    componentView:rootView];
+  RCTMountingManager *mountingManager = _mountingManager;
+  RCTExecuteOnMainQueue(^{
+    UIView<RCTComponentViewProtocol> *rootView =
+        [mountingManager.componentViewRegistry componentViewByTag:surface.rootTag];
+    [mountingManager.componentViewRegistry enqueueComponentViewWithComponentHandle:RootShadowNode::Handle()
+                                                                               tag:surface.rootTag
+                                                                     componentView:rootView];
+  });
 
   [surface _unsetStage:(RCTSurfaceStagePrepared | RCTSurfaceStageMounted)];
 }