From 48dbc393b48f7b2cf27b66e0b16da57ffaba4e7a Mon Sep 17 00:00:00 2001
From: Ruslan Tkhakokhov <rthakohov@google.com>
Date: Fri, 12 May 2023 01:01:51 +0000
Subject: [PATCH] Allow BackupManagerMonitorWrapper to wrap null values

Check the underlying monitor value is not null before proxying the call
in the onEvent() method.

Bug: 282075312
Test: atest BackupManagerMonitorWrapperTest
Change-Id: Iece25d81bc9ec765244898589222491c16ca629a
---
 .../backup/BackupManagerMonitorWrapper.java   | 15 ++++-
 .../BackupManagerMonitorWrapperTest.java      | 66 +++++++++++++++++++
 2 files changed, 79 insertions(+), 2 deletions(-)
 create mode 100644 core/tests/coretests/src/android/app/backup/BackupManagerMonitorWrapperTest.java

diff --git a/core/java/android/app/backup/BackupManagerMonitorWrapper.java b/core/java/android/app/backup/BackupManagerMonitorWrapper.java
index 0b189958ef0ad..39bfb1bd7a55e 100644
--- a/core/java/android/app/backup/BackupManagerMonitorWrapper.java
+++ b/core/java/android/app/backup/BackupManagerMonitorWrapper.java
@@ -16,9 +16,12 @@
 
 package android.app.backup;
 
+import android.annotation.Nullable;
 import android.os.Bundle;
 import android.os.RemoteException;
 
+import com.android.internal.annotations.VisibleForTesting;
+
 /**
  * Wrapper around {@link BackupManagerMonitor} that helps with IPC between the caller of backup
  * APIs and the backup service.
@@ -26,16 +29,24 @@ import android.os.RemoteException;
  * The caller implements {@link BackupManagerMonitor} and passes it into framework APIs that run on
  * the caller's process. Those framework APIs will then wrap it around this class when doing the
  * actual IPC.
+ *
+ * @hide
  */
-class BackupManagerMonitorWrapper extends IBackupManagerMonitor.Stub {
+@VisibleForTesting
+public class BackupManagerMonitorWrapper extends IBackupManagerMonitor.Stub {
+    @Nullable
     private final BackupManagerMonitor mMonitor;
 
-    BackupManagerMonitorWrapper(BackupManagerMonitor monitor) {
+    public BackupManagerMonitorWrapper(@Nullable BackupManagerMonitor monitor) {
         mMonitor = monitor;
     }
 
     @Override
     public void onEvent(final Bundle event) throws RemoteException {
+        if (mMonitor == null) {
+            // It's valid for the underlying monitor to be null, so just return.
+            return;
+        }
         mMonitor.onEvent(event);
     }
 }
diff --git a/core/tests/coretests/src/android/app/backup/BackupManagerMonitorWrapperTest.java b/core/tests/coretests/src/android/app/backup/BackupManagerMonitorWrapperTest.java
new file mode 100644
index 0000000000000..1f5e0cf52d5c8
--- /dev/null
+++ b/core/tests/coretests/src/android/app/backup/BackupManagerMonitorWrapperTest.java
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.app.backup;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+import android.os.Bundle;
+import android.platform.test.annotations.Presubmit;
+
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+@Presubmit
+@RunWith(AndroidJUnit4.class)
+public class BackupManagerMonitorWrapperTest {
+    @Mock
+    private BackupManagerMonitor mMonitor;
+    private BackupManagerMonitorWrapper mMonitorWrapper;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+    }
+
+    @Test
+    public void testOnEvent_propagatesToMonitor() throws Exception {
+        mMonitorWrapper = new BackupManagerMonitorWrapper(mMonitor);
+        Bundle eventBundle = new Bundle();
+
+        mMonitorWrapper.onEvent(eventBundle);
+
+        verify(mMonitor, times(/* wantedNumberOfInvocations */ 1)).onEvent(eq(eventBundle));
+    }
+
+    @Test
+    public void testOnEvent_nullMonitor_eventIsIgnored() throws Exception {
+        mMonitorWrapper = new BackupManagerMonitorWrapper(/* monitor */ null);
+
+        mMonitorWrapper.onEvent(new Bundle());
+
+        verify(mMonitor, never()).onEvent(any());
+    }
+}