From c58ce9a8677338937aa4b2f18840ea1e26d06b20 Mon Sep 17 00:00:00 2001
From: mincheli <mincheli@google.com>
Date: Thu, 10 Sep 2020 17:42:35 +0800
Subject: [PATCH] Prevents the broadcastReceiver unregistered when it's not
 registerd

WindowMagnificationManager monitors the screen state.
And when requestConnection(false) is called before
requestConnection(true), the broadcastReceiver would be unregistered
even it is not registered yet. And it may lead to crash.

Bug: 167804868
Test: atest WindowMagnificationManagerTest
Change-Id: Ib61b00afe79d21a5e944affe8c5492aef90f0399
---
 .../WindowMagnificationManager.java              | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/services/accessibility/java/com/android/server/accessibility/magnification/WindowMagnificationManager.java b/services/accessibility/java/com/android/server/accessibility/magnification/WindowMagnificationManager.java
index d3d56d7f857d5..9cbd78bf44823 100644
--- a/services/accessibility/java/com/android/server/accessibility/magnification/WindowMagnificationManager.java
+++ b/services/accessibility/java/com/android/server/accessibility/magnification/WindowMagnificationManager.java
@@ -68,6 +68,7 @@ public class WindowMagnificationManager implements
     private SparseArray<WindowMagnifier> mWindowMagnifiers = new SparseArray<>();
     private int mUserId;
 
+    private boolean mReceiverRegistered = false;
     @VisibleForTesting
     protected final BroadcastReceiver mScreenStateReceiver = new BroadcastReceiver() {
         @Override
@@ -150,10 +151,16 @@ public class WindowMagnificationManager implements
             }
             if (connect) {
                 final IntentFilter intentFilter = new IntentFilter(Intent.ACTION_SCREEN_OFF);
-                mContext.registerReceiver(mScreenStateReceiver, intentFilter);
+                if (!mReceiverRegistered) {
+                    mContext.registerReceiver(mScreenStateReceiver, intentFilter);
+                    mReceiverRegistered = true;
+                }
             } else {
                 disableAllWindowMagnifiers();
-                mContext.unregisterReceiver(mScreenStateReceiver);
+                if (mReceiverRegistered) {
+                    mContext.unregisterReceiver(mScreenStateReceiver);
+                    mReceiverRegistered = false;
+                }
             }
         }
 
@@ -240,6 +247,9 @@ public class WindowMagnificationManager implements
     void enableWindowMagnification(int displayId, float scale, float centerX, float centerY,
             @Nullable Runnable endCallback) {
         synchronized (mLock) {
+            if (mConnectionWrapper == null) {
+                return;
+            }
             WindowMagnifier magnifier = mWindowMagnifiers.get(displayId);
             if (magnifier == null) {
                 magnifier = createWindowMagnifier(displayId);
@@ -269,7 +279,7 @@ public class WindowMagnificationManager implements
     void disableWindowMagnification(int displayId, boolean clear, Runnable endCallback) {
         synchronized (mLock) {
             WindowMagnifier magnifier = mWindowMagnifiers.get(displayId);
-            if (magnifier == null) {
+            if (magnifier == null || mConnectionWrapper == null) {
                 return;
             }
             magnifier.disableWindowMagnificationInternal(endCallback);