diff --git a/services/core/java/com/android/server/vcn/util/PersistableBundleUtils.java b/services/core/java/com/android/server/vcn/util/PersistableBundleUtils.java index 73054ce046239..7d276c7976769 100644 --- a/services/core/java/com/android/server/vcn/util/PersistableBundleUtils.java +++ b/services/core/java/com/android/server/vcn/util/PersistableBundleUtils.java @@ -17,15 +17,31 @@ package com.android.server.vcn.util; import android.annotation.NonNull; +import android.annotation.Nullable; +import android.os.ParcelUuid; import android.os.PersistableBundle; +import java.io.File; +import java.io.FileInputStream; +import java.io.FileOutputStream; +import java.io.IOException; import java.util.ArrayList; +import java.util.LinkedHashMap; import java.util.List; +import java.util.Map; +import java.util.Map.Entry; +import java.util.Objects; +import java.util.concurrent.locks.ReadWriteLock; +import java.util.concurrent.locks.ReentrantReadWriteLock; /** @hide */ public class PersistableBundleUtils { private static final String LIST_KEY_FORMAT = "LIST_ITEM_%d"; - private static final String LIST_LENGTH_KEY = "LIST_LENGTH"; + private static final String COLLECTION_SIZE_KEY = "COLLECTION_LENGTH"; + private static final String MAP_KEY_FORMAT = "MAP_KEY_%d"; + private static final String MAP_VALUE_FORMAT = "MAP_VALUE_%d"; + + private static final String PARCEL_UUID_KEY = "PARCEL_UUID"; /** * Functional interface to convert an object of the specified type to a PersistableBundle. @@ -56,6 +72,33 @@ public class PersistableBundleUtils { T fromPersistableBundle(PersistableBundle in); } + /** + * Converts a ParcelUuid to a PersistableBundle. + * + *

To avoid key collisions, NO additional key/value pairs should be added to the returned + * PersistableBundle object. + * + * @param uuid a ParcelUuid instance to persist + * @return the PersistableBundle instance + */ + public static PersistableBundle fromParcelUuid(ParcelUuid uuid) { + final PersistableBundle result = new PersistableBundle(); + + result.putString(PARCEL_UUID_KEY, uuid.toString()); + + return result; + } + + /** + * Converts from a PersistableBundle to a ParcelUuid. + * + * @param bundle the PersistableBundle containing the ParcelUuid + * @return the ParcelUuid instance + */ + public static ParcelUuid toParcelUuid(PersistableBundle bundle) { + return ParcelUuid.fromString(bundle.getString(PARCEL_UUID_KEY)); + } + /** * Converts from a list of Persistable objects to a single PersistableBundle. * @@ -72,7 +115,7 @@ public class PersistableBundleUtils { @NonNull List in, @NonNull Serializer serializer) { final PersistableBundle result = new PersistableBundle(); - result.putInt(LIST_LENGTH_KEY, in.size()); + result.putInt(COLLECTION_SIZE_KEY, in.size()); for (int i = 0; i < in.size(); i++) { final String key = String.format(LIST_KEY_FORMAT, i); result.putPersistableBundle(key, serializer.toPersistableBundle(in.get(i))); @@ -91,7 +134,7 @@ public class PersistableBundleUtils { @NonNull public static List toList( @NonNull PersistableBundle in, @NonNull Deserializer deserializer) { - final int listLength = in.getInt(LIST_LENGTH_KEY); + final int listLength = in.getInt(COLLECTION_SIZE_KEY); final ArrayList result = new ArrayList<>(listLength); for (int i = 0; i < listLength; i++) { @@ -102,4 +145,141 @@ public class PersistableBundleUtils { } return result; } + + /** + * Converts from a Map of Persistable objects to a single PersistableBundle. + * + *

To avoid key collisions, NO additional key/value pairs should be added to the returned + * PersistableBundle object. + * + * @param the type of the map-key to convert to the PersistableBundle + * @param the type of the map-value to convert to the PersistableBundle + * @param in the Map of objects implementing the {@link Persistable} interface + * @param keySerializer an implementation of the {@link Serializer} functional interface that + * converts a map-key of type T to a PersistableBundle + * @param valueSerializer an implementation of the {@link Serializer} functional interface that + * converts a map-value of type E to a PersistableBundle + */ + @NonNull + public static PersistableBundle fromMap( + @NonNull Map in, + @NonNull Serializer keySerializer, + @NonNull Serializer valueSerializer) { + final PersistableBundle result = new PersistableBundle(); + + result.putInt(COLLECTION_SIZE_KEY, in.size()); + int i = 0; + for (Entry entry : in.entrySet()) { + final String keyKey = String.format(MAP_KEY_FORMAT, i); + final String valueKey = String.format(MAP_VALUE_FORMAT, i); + result.putPersistableBundle(keyKey, keySerializer.toPersistableBundle(entry.getKey())); + result.putPersistableBundle( + valueKey, valueSerializer.toPersistableBundle(entry.getValue())); + + i++; + } + + return result; + } + + /** + * Converts from a PersistableBundle to a Map of objects. + * + *

In an attempt to preserve ordering, the returned map will be a LinkedHashMap. However, the + * guarantees on the ordering can only ever be as strong as the map that was serialized in + * {@link fromMap()}. If the initial map that was serialized had no ordering guarantees, the + * deserialized map similarly may be of a non-deterministic order. + * + * @param the type of the map-key to convert from a PersistableBundle + * @param the type of the map-value to convert from a PersistableBundle + * @param in the PersistableBundle containing the persisted Map + * @param keyDeserializer an implementation of the {@link Deserializer} functional interface + * that builds the relevant type of map-key. + * @param valueDeserializer an implementation of the {@link Deserializer} functional interface + * that builds the relevant type of map-value. + * @return An instance of the parsed map as a LinkedHashMap (in an attempt to preserve + * ordering). + */ + @NonNull + public static LinkedHashMap toMap( + @NonNull PersistableBundle in, + @NonNull Deserializer keyDeserializer, + @NonNull Deserializer valueDeserializer) { + final int mapSize = in.getInt(COLLECTION_SIZE_KEY); + final LinkedHashMap result = new LinkedHashMap<>(mapSize); + + for (int i = 0; i < mapSize; i++) { + final String keyKey = String.format(MAP_KEY_FORMAT, i); + final String valueKey = String.format(MAP_VALUE_FORMAT, i); + final PersistableBundle keyBundle = in.getPersistableBundle(keyKey); + final PersistableBundle valueBundle = in.getPersistableBundle(valueKey); + + final K key = keyDeserializer.fromPersistableBundle(keyBundle); + final V value = valueDeserializer.fromPersistableBundle(valueBundle); + result.put(key, value); + } + return result; + } + + /** + * Ensures safe reading and writing of {@link PersistableBundle}s to and from disk. + * + *

This class will enforce exclusion between reads and writes using the standard semantics of + * a ReadWriteLock. Specifically, concurrent readers ARE allowed, but reads/writes from/to the + * file are mutually exclusive. In other words, for an unbounded number n, the acceptable states + * are n readers, OR 1 writer (but not both). + */ + public static class LockingReadWriteHelper { + private final ReadWriteLock mDiskLock = new ReentrantReadWriteLock(); + private final String mPath; + + public LockingReadWriteHelper(@NonNull String path) { + mPath = Objects.requireNonNull(path, "fileName was null"); + } + + /** + * Reads the {@link PersistableBundle} from the disk. + * + * @return the PersistableBundle, if the file existed, or null otherwise + */ + @Nullable + public PersistableBundle readFromDisk() throws IOException { + try { + mDiskLock.readLock().lock(); + final File file = new File(mPath); + if (!file.exists()) { + return null; + } + + try (FileInputStream fis = new FileInputStream(file)) { + return PersistableBundle.readFromStream(fis); + } + } finally { + mDiskLock.readLock().unlock(); + } + } + + /** + * Writes a {@link PersistableBundle} to disk. + * + * @param bundle the {@link PersistableBundle} to write to disk + */ + public void writeToDisk(@NonNull PersistableBundle bundle) throws IOException { + Objects.requireNonNull(bundle, "bundle was null"); + + try { + mDiskLock.writeLock().lock(); + final File file = new File(mPath); + if (!file.exists()) { + file.getParentFile().mkdirs(); + } + + try (FileOutputStream fos = new FileOutputStream(file)) { + bundle.writeToStream(fos); + } + } finally { + mDiskLock.writeLock().unlock(); + } + } + } } diff --git a/tests/vcn/java/com/android/server/vcn/util/PersistableBundleUtilsTest.java b/tests/vcn/java/com/android/server/vcn/util/PersistableBundleUtilsTest.java index f78eeb69b5eb6..07d3049ab6edf 100644 --- a/tests/vcn/java/com/android/server/vcn/util/PersistableBundleUtilsTest.java +++ b/tests/vcn/java/com/android/server/vcn/util/PersistableBundleUtilsTest.java @@ -28,6 +28,7 @@ import org.junit.runner.RunWith; import java.util.ArrayList; import java.util.Arrays; +import java.util.LinkedHashMap; import java.util.List; import java.util.Objects; @@ -40,6 +41,43 @@ public class PersistableBundleUtilsTest { private static final int NUM_COLLECTION_ENTRIES = 10; + private static class TestKey { + private static final String TEST_INTEGER_KEY = + "mTestInteger"; // Purposely colliding with keys of test class to ensure namespacing + private final int mTestInteger; + + TestKey(int testInteger) { + mTestInteger = testInteger; + } + + TestKey(PersistableBundle in) { + mTestInteger = in.getInt(TEST_INTEGER_KEY); + } + + public PersistableBundle toPersistableBundle() { + final PersistableBundle result = new PersistableBundle(); + + result.putInt(TEST_INTEGER_KEY, mTestInteger); + + return result; + } + + @Override + public int hashCode() { + return Objects.hash(mTestInteger); + } + + @Override + public boolean equals(Object o) { + if (!(o instanceof TestKey)) { + return false; + } + + final TestKey other = (TestKey) o; + return mTestInteger == other.mTestInteger; + } + } + private static class TestClass { private static final String TEST_INTEGER_KEY = "mTestInteger"; private final int mTestInteger; @@ -113,7 +151,7 @@ public class PersistableBundleUtilsTest { } @Test - public void testConversionLossless() throws Exception { + public void testListConversionLossless() throws Exception { final List sourceList = new ArrayList<>(); for (int i = 0; i < NUM_COLLECTION_ENTRIES; i++) { final PersistableBundle innerBundle = new PersistableBundle(); @@ -128,4 +166,27 @@ public class PersistableBundleUtilsTest { assertEquals(sourceList, resultList); } + + @Test + public void testMapConversionLossless() throws Exception { + final LinkedHashMap sourceMap = new LinkedHashMap<>(); + for (int i = 0; i < NUM_COLLECTION_ENTRIES; i++) { + final TestKey key = new TestKey(i * i); + + final PersistableBundle innerBundle = new PersistableBundle(); + innerBundle.putInt(TEST_KEY, i); + final TestClass value = + new TestClass(i, TEST_INT_ARRAY, TEST_STRING_PREFIX + i, innerBundle); + + sourceMap.put(key, value); + } + + final PersistableBundle bundled = + PersistableBundleUtils.fromMap( + sourceMap, TestKey::toPersistableBundle, TestClass::toPersistableBundle); + final LinkedHashMap resultList = + PersistableBundleUtils.toMap(bundled, TestKey::new, TestClass::new); + + assertEquals(sourceMap, resultList); + } }