From b9396cd74419dd4165fb051605076d19b1c18905 Mon Sep 17 00:00:00 2001
From: Andy Street <andrews@fb.com>
Date: Thu, 7 Apr 2016 13:10:56 -0700
Subject: [PATCH] Synchronize ProgressBar constructors

Summary: If a ProgressBar is created on the shadow thread (for measurement) at the same time one is created on the UI thread, we hit a race condition which sometimes results in a crash (##java.lang.NullPointerException: Null pointer exception during instruction 'invoke-static {v5}, android.animation.AnimatorSet$Node android.animation.AnimatorSet$Node.access$200(android.animation.AnimatorSet$Node) // method@153'##). This diff synchronizes the ctors.

Reviewed By: foghina

Differential Revision: D3151037

fb-gh-sync-id: 8ed96d6debdc1a5fa2f9bd037bfb75def25be3e8
fbshipit-source-id: 8ed96d6debdc1a5fa2f9bd037bfb75def25be3e8
---
 .../progressbar/ProgressBarContainerView.java    |  2 +-
 .../views/progressbar/ProgressBarShadowNode.java |  2 +-
 .../progressbar/ReactProgressBarViewManager.java | 16 ++++++++++++++++
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/ReactAndroid/src/main/java/com/facebook/react/views/progressbar/ProgressBarContainerView.java b/ReactAndroid/src/main/java/com/facebook/react/views/progressbar/ProgressBarContainerView.java
index 233981506..d71b66922 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/views/progressbar/ProgressBarContainerView.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/views/progressbar/ProgressBarContainerView.java
@@ -31,7 +31,7 @@ import com.facebook.react.bridge.JSApplicationIllegalArgumentException;
 
   public void setStyle(@Nullable String styleName) {
     int style = ReactProgressBarViewManager.getStyleFromString(styleName);
-    mProgressBar = new ProgressBar(getContext(), null, style);
+    mProgressBar = ReactProgressBarViewManager.createProgressBar(getContext(), style);
     mProgressBar.setMax(MAX_PROGRESS);
     removeAllViews();
     addView(
diff --git a/ReactAndroid/src/main/java/com/facebook/react/views/progressbar/ProgressBarShadowNode.java b/ReactAndroid/src/main/java/com/facebook/react/views/progressbar/ProgressBarShadowNode.java
index ee272724b..ce85293fb 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/views/progressbar/ProgressBarShadowNode.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/views/progressbar/ProgressBarShadowNode.java
@@ -61,7 +61,7 @@ public class ProgressBarShadowNode extends LayoutShadowNode implements CSSNode.M
       MeasureOutput measureOutput) {
     final int style = ReactProgressBarViewManager.getStyleFromString(getStyle());
     if (!mMeasured.contains(style)) {
-      ProgressBar progressBar = new ProgressBar(getThemedContext(), null, style);
+      ProgressBar progressBar = ReactProgressBarViewManager.createProgressBar(getThemedContext(), style);
       final int spec = View.MeasureSpec.makeMeasureSpec(
           ViewGroup.LayoutParams.WRAP_CONTENT,
           View.MeasureSpec.UNSPECIFIED);
diff --git a/ReactAndroid/src/main/java/com/facebook/react/views/progressbar/ReactProgressBarViewManager.java b/ReactAndroid/src/main/java/com/facebook/react/views/progressbar/ReactProgressBarViewManager.java
index 82601cedd..38454282e 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/views/progressbar/ReactProgressBarViewManager.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/views/progressbar/ReactProgressBarViewManager.java
@@ -11,6 +11,9 @@ package com.facebook.react.views.progressbar;
 
 import javax.annotation.Nullable;
 
+import android.content.Context;
+import android.widget.ProgressBar;
+
 import com.facebook.react.bridge.JSApplicationIllegalArgumentException;
 import com.facebook.react.uimanager.BaseViewManager;
 import com.facebook.react.uimanager.annotations.ReactProp;
@@ -33,6 +36,19 @@ public class ReactProgressBarViewManager extends
   /* package */ static final String REACT_CLASS = "AndroidProgressBar";
   /* package */ static final String DEFAULT_STYLE = "Normal";
 
+  private static Object sProgressBarCtorLock = new Object();
+
+  /**
+   * We create ProgressBars on both the UI and shadow threads. There is a race condition in the
+   * ProgressBar constructor that may cause crashes when two ProgressBars are constructed at the
+   * same time on two different threads. This static ctor wrapper protects against that.
+   */
+  public static ProgressBar createProgressBar(Context context, int style) {
+    synchronized (sProgressBarCtorLock) {
+      return new ProgressBar(context, null, style);
+    }
+  }
+
   @Override
   public String getName() {
     return REACT_CLASS;