Fix MonotonicClock persistence (0c0996b5) · Commits · e / os / android_frameworks_base

core/java/com/android/internal/os/MonotonicClock.java

+26 −16

Original line number	Diff line number	Diff line
		@@ -17,11 +17,11 @@
		package com.android.internal.os;

		import android.annotation.NonNull;
		import android.annotation.Nullable;
		import android.util.AtomicFile;
		import android.util.Log;
		import android.util.Xml;

		import com.android.internal.annotations.VisibleForTesting;
		import com.android.modules.utils.TypedXmlPullParser;
		import com.android.modules.utils.TypedXmlSerializer;

		@@ -49,21 +49,28 @@ public class MonotonicClock {

		private final AtomicFile mFile;
		private final Clock mClock;
		private long mTimeshift;
		private final long mTimeshift;

		public static final long UNDEFINED = -1;

		public MonotonicClock(File file) {
		mFile = new AtomicFile(file);
		mClock = Clock.SYSTEM_CLOCK;
		read();
		this (file, Clock.SYSTEM_CLOCK.elapsedRealtime(), Clock.SYSTEM_CLOCK);
		}

		public MonotonicClock(long monotonicTime, @NonNull Clock clock) {
		this(null, monotonicTime, clock);
		}

		public MonotonicClock(@Nullable File file, long monotonicTime, @NonNull Clock clock) {
		mClock = clock;
		if (file != null) {
		mFile = new AtomicFile(file);
		mTimeshift = read(monotonicTime - mClock.elapsedRealtime());
		} else {
		mFile = null;
		mTimeshift = monotonicTime - mClock.elapsedRealtime();
		}
		}

		/**
		* Returns time in milliseconds, based on SystemClock.elapsedTime, adjusted so that
		@@ -81,15 +88,16 @@ public class MonotonicClock {
		return mTimeshift + elapsedRealtimeMs;
		}

		private void read() {
		private long read(long defaultTimeshift) {
		if (!mFile.exists()) {
		return;
		return defaultTimeshift;
		}

		try {
		readXml(new ByteArrayInputStream(mFile.readFully()), Xml.newBinaryPullParser());
		return readXml(new ByteArrayInputStream(mFile.readFully()), Xml.newBinaryPullParser());
		} catch (IOException e) {
		Log.e(TAG, "Cannot load monotonic clock from " + mFile.getBaseFile(), e);
		return defaultTimeshift;
		}
		}

		@@ -102,18 +110,21 @@ public class MonotonicClock {
		return;
		}

		try (FileOutputStream out = mFile.startWrite()) {
		FileOutputStream out = null;
		try {
		out = mFile.startWrite();
		writeXml(out, Xml.newBinarySerializer());
		mFile.finishWrite(out);
		} catch (IOException e) {
		Log.e(TAG, "Cannot write monotonic clock to " + mFile.getBaseFile(), e);
		mFile.failWrite(out);
		}
		}

		/**
		* Parses an XML file containing the persistent state of the monotonic clock.
		*/
		@VisibleForTesting
		public void readXml(InputStream inputStream, TypedXmlPullParser parser) throws IOException {
		private long readXml(InputStream inputStream, TypedXmlPullParser parser) throws IOException {
		long savedTimeshift = 0;
		try {
		parser.setInput(inputStream, StandardCharsets.UTF_8.name());
		@@ -128,14 +139,13 @@ public class MonotonicClock {
		} catch (XmlPullParserException e) {
		throw new IOException(e);
		}
		mTimeshift = savedTimeshift - mClock.elapsedRealtime();
		return savedTimeshift - mClock.elapsedRealtime();
		}

		/**
		* Creates an XML file containing the persistent state of the monotonic clock.
		*/
		@VisibleForTesting
		public void writeXml(OutputStream out, TypedXmlSerializer serializer) throws IOException {
		private void writeXml(OutputStream out, TypedXmlSerializer serializer) throws IOException {
		serializer.setOutput(out, StandardCharsets.UTF_8.name());
		serializer.startDocument(null, true);
		serializer.startTag(null, XML_TAG_MONOTONIC_TIME);

core/tests/coretests/src/com/android/internal/os/MonotonicClockTest.java

+38 −10

Original line number	Diff line number	Diff line
		@@ -18,39 +18,67 @@ package com.android.internal.os;

		import static com.google.common.truth.Truth.assertThat;

		import android.util.Xml;

		import androidx.test.filters.SmallTest;
		import androidx.test.runner.AndroidJUnit4;

		import org.junit.Before;
		import org.junit.Test;
		import org.junit.runner.RunWith;

		import java.io.ByteArrayInputStream;
		import java.io.ByteArrayOutputStream;
		import java.io.File;
		import java.io.FileWriter;
		import java.io.IOException;
		import java.nio.file.Files;

		@RunWith(AndroidJUnit4.class)
		@SmallTest
		public class MonotonicClockTest {
		private final MockClock mClock = new MockClock();
		private File mFile;

		@Before
		public void setup() throws IOException {
		File systemDir = Files.createTempDirectory("MonotonicClockTest").toFile();
		mFile = new File(systemDir, "test_monotonic_clock.xml");
		if (mFile.exists()) {
		assertThat(mFile.delete()).isTrue();
		}
		}

		@Test
		public void persistence() throws IOException {
		MonotonicClock monotonicClock = new MonotonicClock(1000, mClock);
		MonotonicClock monotonicClock = new MonotonicClock(mFile, 1000, mClock);
		mClock.realtime = 234;

		assertThat(monotonicClock.monotonicTime()).isEqualTo(1234);

		ByteArrayOutputStream out = new ByteArrayOutputStream();
		monotonicClock.writeXml(out, Xml.newBinarySerializer());
		monotonicClock.write();

		mClock.realtime = 42;
		MonotonicClock newMonotonicClock = new MonotonicClock(0, mClock);
		ByteArrayInputStream in = new ByteArrayInputStream(out.toByteArray());
		newMonotonicClock.readXml(in, Xml.newBinaryPullParser());
		MonotonicClock newMonotonicClock = new MonotonicClock(mFile, 0, mClock);

		mClock.realtime = 2000;
		assertThat(newMonotonicClock.monotonicTime()).isEqualTo(1234 - 42 + 2000);
		}

		@Test
		public void constructor() {
		MonotonicClock monotonicClock = new MonotonicClock(null, 1000, mClock);
		mClock.realtime = 234;

		assertThat(monotonicClock.monotonicTime()).isEqualTo(1234);
		}

		@Test
		public void corruptedFile() throws IOException {
		// Create an invalid binary XML file to cause IOException: "Unexpected magic number"
		try (FileWriter w = new FileWriter(mFile)) {
		w.write("garbage");
		}

		MonotonicClock monotonicClock = new MonotonicClock(mFile, 1000, mClock);
		mClock.realtime = 234;

		assertThat(monotonicClock.monotonicTime()).isEqualTo(1234);
		}
		}