Resolving race condition while writing recent taskids am: fd0bd4f39d am: c9e7c49def (888a4596) · Commits · e / os / android_frameworks_base

services/core/java/com/android/server/am/TaskPersister.java

+48 −39

Original line number	Diff line number	Diff line
		@@ -87,6 +87,8 @@ public class TaskPersister {
		private final RecentTasks mRecentTasks;
		private final SparseArray<SparseBooleanArray> mTaskIdsInFile = new SparseArray<>();
		private final File mTaskIdsDir;
		// To lock file operations in TaskPersister
		private final Object mIoLock = new Object();

		/**
		* Value determines write delay mode as follows: < 0 We are Flushing. No delays between writes
		@@ -195,6 +197,7 @@ public class TaskPersister {
		return mTaskIdsInFile.get(userId).clone();
		}
		final SparseBooleanArray persistedTaskIds = new SparseBooleanArray();
		synchronized (mIoLock) {
		BufferedReader reader = null;
		String line;
		try {
		@@ -212,20 +215,19 @@ public class TaskPersister {
		} finally {
		IoUtils.closeQuietly(reader);
		}
		}
		mTaskIdsInFile.put(userId, persistedTaskIds);
		return persistedTaskIds.clone();
		}


		@VisibleForTesting
		void maybeWritePersistedTaskIdsForUser(@NonNull SparseBooleanArray taskIds, int userId) {
		void writePersistedTaskIdsForUser(@NonNull SparseBooleanArray taskIds, int userId) {
		if (userId < 0) {
		return;
		}
		SparseBooleanArray persistedIdsInFile = mTaskIdsInFile.get(userId);
		if (persistedIdsInFile != null && persistedIdsInFile.equals(taskIds)) {
		return;
		}
		final File persistedTaskIdsFile = getUserPersistedTaskIdsFile(userId);
		synchronized (mIoLock) {
		BufferedWriter writer = null;
		try {
		writer = new BufferedWriter(new FileWriter(persistedTaskIdsFile));
		@@ -240,7 +242,7 @@ public class TaskPersister {
		} finally {
		IoUtils.closeQuietly(writer);
		}
		mTaskIdsInFile.put(userId, taskIds.clone());
		}
		}

		void unloadUserDataFromMemory(int userId) {
		@@ -543,16 +545,23 @@ public class TaskPersister {
		}

		private void writeTaskIdsFiles() {
		int candidateUserIds[];
		SparseArray<SparseBooleanArray> changedTaskIdsPerUser = new SparseArray<>();
		synchronized (mService) {
		candidateUserIds = mRecentTasks.usersWithRecentsLoadedLocked();
		for (int userId : mRecentTasks.usersWithRecentsLoadedLocked()) {
		SparseBooleanArray taskIdsToSave = mRecentTasks.mPersistedTaskIds.get(userId);
		SparseBooleanArray persistedIdsInFile = mTaskIdsInFile.get(userId);
		if (persistedIdsInFile != null && persistedIdsInFile.equals(taskIdsToSave)) {
		continue;
		} else {
		SparseBooleanArray taskIdsToSaveCopy = taskIdsToSave.clone();
		mTaskIdsInFile.put(userId, taskIdsToSaveCopy);
		changedTaskIdsPerUser.put(userId, taskIdsToSaveCopy);
		}
		}
		SparseBooleanArray taskIdsToSave;
		for (int userId : candidateUserIds) {
		synchronized (mService) {
		taskIdsToSave = mRecentTasks.mPersistedTaskIds.get(userId).clone();
		}
		maybeWritePersistedTaskIdsForUser(taskIdsToSave, userId);
		for (int i = 0; i < changedTaskIdsPerUser.size(); i++) {
		writePersistedTaskIdsForUser(changedTaskIdsPerUser.valueAt(i),
		changedTaskIdsPerUser.keyAt(i));
		}
		}

services/tests/servicestests/src/com/android/server/am/TaskPersisterTest.java

+1 −1

Original line number	Diff line number	Diff line
		@@ -62,7 +62,7 @@ public class TaskPersisterTest extends AndroidTestCase {
		for (int i = 0; i < 100; i++) {
		taskIdsOnFile.put(getRandomTaskIdForUser(testUserId), true);
		}
		mTaskPersister.maybeWritePersistedTaskIdsForUser(taskIdsOnFile, testUserId);
		mTaskPersister.writePersistedTaskIdsForUser(taskIdsOnFile, testUserId);
		SparseBooleanArray newTaskIdsOnFile = mTaskPersister
		.loadPersistedTaskIdsForUser(testUserId);
		assertTrue("TaskIds written differ from TaskIds read back from file",