Frameworks: Move SharedPreferencesImpl to Future (70b600d4) · Commits · e / os / android_frameworks_base

core/java/android/app/SharedPreferencesImpl.java

+74 −54

Original line number	Diff line number	Diff line
		@@ -50,6 +50,11 @@ import java.util.Map;
		import java.util.Set;
		import java.util.WeakHashMap;
		import java.util.concurrent.CountDownLatch;
		import java.util.concurrent.ExecutionException;
		import java.util.concurrent.Future;
		import java.util.concurrent.FutureTask;
		import java.util.concurrent.TimeUnit;
		import java.util.concurrent.TimeoutException;

		final class SharedPreferencesImpl implements SharedPreferences {
		private static final String TAG = "SharedPreferencesImpl";
		@@ -69,15 +74,11 @@ final class SharedPreferencesImpl implements SharedPreferences {
		private final Object mLock = new Object();
		private final Object mWritingToDiskLock = new Object();

		@GuardedBy("mLock")
		private Map<String, Object> mMap;
		private Future<Map<String, Object>> mMap;

		@GuardedBy("mLock")
		private int mDiskWritesInFlight = 0;

		@GuardedBy("mLock")
		private boolean mLoaded = false;

		@GuardedBy("mLock")
		private StructTimespec mStatTimestamp;

		@@ -105,27 +106,18 @@ final class SharedPreferencesImpl implements SharedPreferences {
		mFile = file;
		mBackupFile = makeBackupFile(file);
		mMode = mode;
		mLoaded = false;
		mMap = null;
		startLoadFromDisk();
		}

		private void startLoadFromDisk() {
		synchronized (mLock) {
		mLoaded = false;
		}
		new Thread("SharedPreferencesImpl-load") {
		public void run() {
		loadFromDisk();
		}
		}.start();
		FutureTask<Map<String, Object>> futureTask = new FutureTask<>(() -> loadFromDisk());
		mMap = futureTask;
		new Thread(futureTask, "SharedPreferencesImpl-load").start();
		}

		private void loadFromDisk() {
		private Map<String, Object> loadFromDisk() {
		synchronized (mLock) {
		if (mLoaded) {
		return;
		}
		if (mBackupFile.exists()) {
		mFile.delete();
		mBackupFile.renameTo(mFile);
		@@ -158,16 +150,14 @@ final class SharedPreferencesImpl implements SharedPreferences {
		}

		synchronized (mLock) {
		mLoaded = true;
		if (map != null) {
		mMap = map;
		mStatTimestamp = stat.st_mtim;
		mStatSize = stat.st_size;
		} else {
		mMap = new HashMap<>();
		map = new HashMap<>();
		}
		mLock.notifyAll();
		}
		return map;
		}

		static File makeBackupFile(File prefsFile) {
		@@ -226,36 +216,37 @@ final class SharedPreferencesImpl implements SharedPreferences {
		}
		}

		private void awaitLoadedLocked() {
		if (!mLoaded) {
		private @GuardedBy("mLock") Map<String, Object> getLoaded() {
		try {
		return mMap.get();
		} catch (InterruptedException \| ExecutionException e) {
		throw new IllegalStateException(e);
		}
		}
		private @GuardedBy("mLock") Map<String, Object> getLoadedWithBlockGuard() {
		if (!mMap.isDone()) {
		// Raise an explicit StrictMode onReadFromDisk for this
		// thread, since the real read will be in a different
		// thread and otherwise ignored by StrictMode.
		BlockGuard.getThreadPolicy().onReadFromDisk();
		}
		while (!mLoaded) {
		try {
		mLock.wait();
		} catch (InterruptedException unused) {
		}
		}
		return getLoaded();
		}

		@Override
		public Map<String, ?> getAll() {
		Map<String, Object> map = getLoadedWithBlockGuard();
		synchronized (mLock) {
		awaitLoadedLocked();
		//noinspection unchecked
		return new HashMap<String, Object>(mMap);
		return new HashMap<String, Object>(map);
		}
		}

		@Override
		@Nullable
		public String getString(String key, @Nullable String defValue) {
		Map<String, Object> map = getLoadedWithBlockGuard();
		synchronized (mLock) {
		awaitLoadedLocked();
		String v = (String)mMap.get(key);
		String v = (String) map.get(key);
		return v != null ? v : defValue;
		}
		}
		@@ -263,66 +254,65 @@ final class SharedPreferencesImpl implements SharedPreferences {
		@Override
		@Nullable
		public Set<String> getStringSet(String key, @Nullable Set<String> defValues) {
		Map<String, Object> map = getLoadedWithBlockGuard();
		synchronized (mLock) {
		awaitLoadedLocked();
		Set<String> v = (Set<String>) mMap.get(key);
		@SuppressWarnings("unchecked")
		Set<String> v = (Set<String>) map.get(key);
		return v != null ? v : defValues;
		}
		}

		@Override
		public int getInt(String key, int defValue) {
		Map<String, Object> map = getLoadedWithBlockGuard();
		synchronized (mLock) {
		awaitLoadedLocked();
		Integer v = (Integer)mMap.get(key);
		Integer v = (Integer) map.get(key);
		return v != null ? v : defValue;
		}
		}
		@Override
		public long getLong(String key, long defValue) {
		Map<String, Object> map = getLoadedWithBlockGuard();
		synchronized (mLock) {
		awaitLoadedLocked();
		Long v = (Long)mMap.get(key);
		Long v = (Long) map.get(key);
		return v != null ? v : defValue;
		}
		}
		@Override
		public float getFloat(String key, float defValue) {
		Map<String, Object> map = getLoadedWithBlockGuard();
		synchronized (mLock) {
		awaitLoadedLocked();
		Float v = (Float)mMap.get(key);
		Float v = (Float) map.get(key);
		return v != null ? v : defValue;
		}
		}
		@Override
		public boolean getBoolean(String key, boolean defValue) {
		Map<String, Object> map = getLoadedWithBlockGuard();
		synchronized (mLock) {
		awaitLoadedLocked();
		Boolean v = (Boolean)mMap.get(key);
		Boolean v = (Boolean) map.get(key);
		return v != null ? v : defValue;
		}
		}

		@Override
		public boolean contains(String key) {
		Map<String, Object> map = getLoadedWithBlockGuard();
		synchronized (mLock) {
		awaitLoadedLocked();
		return mMap.containsKey(key);
		return map.containsKey(key);
		}
		}

		@Override
		public Editor edit() {
		// TODO: remove the need to call awaitLoadedLocked() when
		// TODO: remove the need to call getLoaded() when
		// requesting an editor. will require some work on the
		// Editor, but then we should be able to do:
		//
		// context.getSharedPreferences(..).edit().putString(..).apply()
		//
		// ... all without blocking.
		synchronized (mLock) {
		awaitLoadedLocked();
		}
		getLoadedWithBlockGuard();

		return new EditorImpl();
		}
		@@ -476,13 +466,43 @@ final class SharedPreferencesImpl implements SharedPreferences {
		// a memory commit comes in when we're already
		// writing to disk.
		if (mDiskWritesInFlight > 0) {
		// We can't modify our mMap as a currently
		// We can't modify our map as a currently
		// in-flight write owns it. Clone it before
		// modifying it.
		// noinspection unchecked
		mMap = new HashMap<String, Object>(mMap);
		mMap = new Future<Map<String, Object>>() {
		private Map<String, Object> mCopiedMap =
		new HashMap<String, Object>(getLoaded());

		@Override
		public boolean cancel(boolean mayInterruptIfRunning) {
		return false;
		}

		@Override
		public boolean isCancelled() {
		return false;
		}

		@Override
		public boolean isDone() {
		return true;
		}

		@Override
		public Map<String, Object> get()
		throws InterruptedException, ExecutionException {
		return mCopiedMap;
		}

		@Override
		public Map<String, Object> get(long timeout, TimeUnit unit)
		throws InterruptedException, ExecutionException, TimeoutException {
		return mCopiedMap;
		}
		};
		}
		mapToWriteToDisk = mMap;
		mapToWriteToDisk = getLoaded();
		mDiskWritesInFlight++;

		boolean hasListeners = mListeners.size() > 0;