From 53ce7b218366cadf181b4f13f135367c5a837ce4 Mon Sep 17 00:00:00 2001
From: Emily Janzer <janzer@fb.com>
Date: Fri, 24 Jan 2020 15:13:20 -0800
Subject: [PATCH] Add @UiThread annotation to methods that update
 DisplayMetrics

Summary:
It seems like DisplayMetricsHolder doesn't have any thread safety policy, but in practice it only updates DisplayMetrics from the main thread. Let's formalize that by adding some annotations to that effect.

Changelog: [Internal]

Reviewed By: mdvacca

Differential Revision: D19417331

fbshipit-source-id: f1d464f228776197fd0df2978c9e8edbaab67850
---
 .../facebook/react/uimanager/DisplayMetricsHolder.java    | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/ReactAndroid/src/main/java/com/facebook/react/uimanager/DisplayMetricsHolder.java b/ReactAndroid/src/main/java/com/facebook/react/uimanager/DisplayMetricsHolder.java
index ab6d1739b0..fa93a240a7 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/uimanager/DisplayMetricsHolder.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/uimanager/DisplayMetricsHolder.java
@@ -13,7 +13,9 @@ import android.util.DisplayMetrics;
 import android.view.Display;
 import android.view.WindowManager;
 import androidx.annotation.Nullable;
+import androidx.annotation.UiThread;
 import com.facebook.infer.annotation.Assertions;
+import com.facebook.react.bridge.UiThreadUtil;
 import com.facebook.react.bridge.WritableNativeMap;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
@@ -37,7 +39,9 @@ public class DisplayMetricsHolder {
    * @deprecated Use {@link #setScreenDisplayMetrics(DisplayMetrics)} instead. See comment above as
    *     to why this is not correct to use.
    */
+  @UiThread
   public static void setWindowDisplayMetrics(DisplayMetrics displayMetrics) {
+    UiThreadUtil.assertOnUiThread();
     sWindowDisplayMetrics = displayMetrics;
   }
 
@@ -48,7 +52,9 @@ public class DisplayMetricsHolder {
     initDisplayMetrics(context);
   }
 
+  @UiThread
   public static void initDisplayMetrics(Context context) {
+    UiThreadUtil.assertOnUiThread();
     DisplayMetrics displayMetrics = context.getResources().getDisplayMetrics();
     DisplayMetricsHolder.setWindowDisplayMetrics(displayMetrics);
 
@@ -95,7 +101,9 @@ public class DisplayMetricsHolder {
     return sWindowDisplayMetrics;
   }
 
+  @UiThread
   public static void setScreenDisplayMetrics(DisplayMetrics screenDisplayMetrics) {
+    UiThreadUtil.assertOnUiThread();
     sScreenDisplayMetrics = screenDisplayMetrics;
   }