Fix ModernAsyncTask to handle exceptions in doInBackground
When cancelling, the exception will be eaten by FutureTask, but
onCancelled would end up never being called due to the exception
causing the code to skip calling postResult.
b/30304893
Change-Id: I548da6c033135fba99192276a99578bdce080b64
diff --git a/compat/java/android/support/v4/content/ModernAsyncTask.java b/compat/java/android/support/v4/content/ModernAsyncTask.java
index 7d9f0c3..34724db 100644
--- a/compat/java/android/support/v4/content/ModernAsyncTask.java
+++ b/compat/java/android/support/v4/content/ModernAsyncTask.java
@@ -30,6 +30,7 @@
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
+import android.os.Binder;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
@@ -125,9 +126,16 @@
@Override
public Result call() throws Exception {
mTaskInvoked.set(true);
-
- Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
- return postResult(doInBackground(mParams));
+ Result result = null;
+ try {
+ Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
+ //noinspection unchecked
+ result = doInBackground(mParams);
+ Binder.flushPendingCommands();
+ } finally {
+ postResult(result);
+ }
+ return result;
}
};
diff --git a/compat/tests/java/android/support/v4/content/ModernAsyncTaskTest.java b/compat/tests/java/android/support/v4/content/ModernAsyncTaskTest.java
new file mode 100644
index 0000000..2905df0
--- /dev/null
+++ b/compat/tests/java/android/support/v4/content/ModernAsyncTaskTest.java
@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2016 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.support.v4.content;
+
+import android.support.test.InstrumentationRegistry;
+import android.support.test.runner.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import static org.junit.Assert.*;
+
+@RunWith(AndroidJUnit4.class)
+public class ModernAsyncTaskTest {
+
+ ModernAsyncTask mModernAsyncTask;
+
+ /**
+ * Test to ensure that onCancelled is always called, even if doInBackground throws an exception.
+ *
+ * @throws Throwable
+ */
+ @Test
+ public void testCancellationWithException() throws Throwable {
+ final CountDownLatch readyToCancel = new CountDownLatch(1);
+ final CountDownLatch readyToThrow = new CountDownLatch(1);
+ final CountDownLatch calledOnCancelled = new CountDownLatch(1);
+ InstrumentationRegistry.getInstrumentation().runOnMainSync(new Runnable() {
+ @Override
+ public void run() {
+ mModernAsyncTask = new ModernAsyncTask() {
+ @Override
+ protected Object doInBackground(Object[] params) {
+ readyToCancel.countDown();
+ try {
+ readyToThrow.await();
+ } catch (InterruptedException e) {}
+ // This exception is expected to be caught and ignored
+ throw new RuntimeException();
+ }
+
+ @Override
+ protected void onCancelled(Object o) {
+ calledOnCancelled.countDown();
+ }
+ };
+ }
+ });
+
+ mModernAsyncTask.execute();
+ if (!readyToCancel.await(5, TimeUnit.SECONDS)) {
+ fail("Test failure: doInBackground did not run in time.");
+ }
+ mModernAsyncTask.cancel(false);
+ readyToThrow.countDown();
+ if (!calledOnCancelled.await(5, TimeUnit.SECONDS)) {
+ fail("onCancelled not called!");
+ }
+ }
+}