Merge "Fix RootScanner to execute scan at least once before cancelling it." into nyc-dev (e5b499bc) · Commits · e / os / android_frameworks_base

packages/MtpDocumentsProvider/src/com/android/mtp/MtpDocumentsProvider.java

+1 −0

Original line number	Diff line number	Diff line
		@@ -404,6 +404,7 @@ public class MtpDocumentsProvider extends DocumentsProvider {
		for (final int id : keySet) {
		closeDeviceInternal(id);
		}
		mRootScanner.pause();
		} catch (InterruptedException\|IOException e) {
		// It should fail unit tests by throwing runtime exception.
		throw new RuntimeException(e);

packages/MtpDocumentsProvider/src/com/android/mtp/RootScanner.java

+21 −11

Original line number	Diff line number	Diff line
		@@ -26,7 +26,6 @@ import java.io.FileNotFoundException;
		import java.util.concurrent.CountDownLatch;
		import java.util.concurrent.ExecutorService;
		import java.util.concurrent.Executors;
		import java.util.concurrent.FutureTask;
		import java.util.concurrent.TimeUnit;

		final class RootScanner {
		@@ -56,7 +55,7 @@ final class RootScanner {
		final MtpDatabase mDatabase;

		ExecutorService mExecutor;
		FutureTask<Void> mCurrentTask;
		private UpdateRootsRunnable mCurrentTask;

		RootScanner(
		ContentResolver resolver,
		@@ -84,13 +83,12 @@ final class RootScanner {
		mExecutor = Executors.newSingleThreadExecutor();
		}
		if (mCurrentTask != null) {
		// Cancel previous task.
		mCurrentTask.cancel(true);
		// Stop previous task.
		mCurrentTask.stop();
		}
		final UpdateRootsRunnable runnable = new UpdateRootsRunnable();
		mCurrentTask = new FutureTask<Void>(runnable, null);
		mExecutor.submit(mCurrentTask);
		return runnable.mFirstScanCompleted;
		mCurrentTask = new UpdateRootsRunnable();
		mExecutor.execute(mCurrentTask);
		return mCurrentTask.mFirstScanCompleted;
		}

		/**
		@@ -112,13 +110,21 @@ final class RootScanner {
		* Runnable to scan roots and update the database information.
		*/
		private final class UpdateRootsRunnable implements Runnable {
		/**
		* Count down latch that specifies the runnable is stopped.
		*/
		final CountDownLatch mStopped = new CountDownLatch(1);

		/**
		* Count down latch that specifies the first scan is completed.
		*/
		final CountDownLatch mFirstScanCompleted = new CountDownLatch(1);

		@Override
		public void run() {
		Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
		int pollingCount = 0;
		while (true) {
		while (mStopped.getCount() > 0) {
		boolean changed = false;

		// Update devices.
		@@ -171,12 +177,16 @@ final class RootScanner {
		// Use SHORT_POLLING_PERIOD for the first SHORT_POLLING_TIMES because it is
		// more likely to add new root just after the device is added.
		// TODO: Use short interval only for a device that is just added.
		Thread.sleep(pollingCount > SHORT_POLLING_TIMES ?
		LONG_POLLING_INTERVAL : SHORT_POLLING_INTERVAL);
		mStopped.await(pollingCount > SHORT_POLLING_TIMES ?
		LONG_POLLING_INTERVAL : SHORT_POLLING_INTERVAL, TimeUnit.MILLISECONDS);
		} catch (InterruptedException exp) {
		break;
		}
		}
		}

		void stop() {
		mStopped.countDown();
		}
		}
		}