From e8a9c64ae8f72bc732ef9d73bd684df1c09e11b6 Mon Sep 17 00:00:00 2001
From: Miranda Kephart <mkephart@google.com>
Date: Mon, 30 Aug 2021 16:04:58 +0000
Subject: [PATCH] Fix race condition causing screenshot view to be added to
 window twice

In some cases, invoking multiple screenshots in quick succession causes
an error as the decor view is added to the window twice. This change
blocks attempting to attach the window between telling the window
manager to add the decor view and getting the callback that it has
been added.

Bug: 190249438
Fix: 190249438
Test: manual
Change-Id: I2bc3a1322651ab312e75bb9e9426909db368d84e
---
 .../android/systemui/screenshot/ScreenshotController.java  | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/packages/SystemUI/src/com/android/systemui/screenshot/ScreenshotController.java b/packages/SystemUI/src/com/android/systemui/screenshot/ScreenshotController.java
index 3fbdc23f55d0e..8def475c192c0 100644
--- a/packages/SystemUI/src/com/android/systemui/screenshot/ScreenshotController.java
+++ b/packages/SystemUI/src/com/android/systemui/screenshot/ScreenshotController.java
@@ -33,6 +33,7 @@ import static java.util.Objects.requireNonNull;
 
 import android.animation.Animator;
 import android.animation.AnimatorListenerAdapter;
+import android.annotation.MainThread;
 import android.annotation.Nullable;
 import android.app.ActivityManager;
 import android.app.ActivityOptions;
@@ -261,6 +262,7 @@ public class ScreenshotController {
     private Bitmap mScreenBitmap;
     private SaveImageInBackgroundTask mSaveInBgTask;
     private boolean mScreenshotTakenInPortrait;
+    private boolean mBlockAttach;
 
     private Animator mScreenshotAnimation;
     private RequestCallback mCurrentRequestCallback;
@@ -731,6 +733,7 @@ public class ScreenshotController {
                     new ViewTreeObserver.OnWindowAttachListener() {
                         @Override
                         public void onWindowAttached() {
+                            mBlockAttach = false;
                             decorView.getViewTreeObserver().removeOnWindowAttachListener(this);
                             action.run();
                         }
@@ -747,14 +750,16 @@ public class ScreenshotController {
         mWindow.setContentView(contentView);
     }
 
+    @MainThread
     private void attachWindow() {
         View decorView = mWindow.getDecorView();
-        if (decorView.isAttachedToWindow()) {
+        if (decorView.isAttachedToWindow() || mBlockAttach) {
             return;
         }
         if (DEBUG_WINDOW) {
             Log.d(TAG, "attachWindow");
         }
+        mBlockAttach = true;
         mWindowManager.addView(decorView, mWindowLayoutParams);
         decorView.requestApplyInsets();
     }