[DataStore] Support backup data with compression (6cc3696a) · Commits · e / os / android_frameworks_base

packages/SettingsLib/DataStore/Android.bp

+1 −0

Original line number	Diff line number	Diff line
		@@ -14,4 +14,5 @@ android_library {
		"androidx.core_core-ktx",
		"guava",
		],
		kotlincflags: ["-Xjvm-default=all"],
		}

packages/SettingsLib/DataStore/src/com/android/settingslib/datastore/BackupCodec.kt

0 → 100644

+98 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2024 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		package com.android.settingslib.datastore

		import androidx.annotation.IntDef
		import java.io.InputStream
		import java.io.OutputStream
		import java.util.zip.Deflater
		import java.util.zip.DeflaterOutputStream
		import java.util.zip.InflaterInputStream

		/** Unique id of the codec. */
		@Target(AnnotationTarget.TYPE)
		@IntDef(
		BackupCodecId.NO_OP.toInt(),
		BackupCodecId.ZIP.toInt(),
		)
		@Retention(AnnotationRetention.SOURCE)
		annotation class BackupCodecId {
		companion object {
		/** Unknown reason of the change. */
		const val NO_OP: Byte = 0
		/** Data is updated. */
		const val ZIP: Byte = 1
		}
		}

		/** How to encode/decode the backup data. */
		interface BackupCodec {
		/** Unique id of the codec. */
		val id: @BackupCodecId Byte

		/** Name of the codec. */
		val name: String

		/** Encodes the backup data. */
		fun encode(outputStream: OutputStream): OutputStream

		/** Decodes the backup data. */
		fun decode(inputStream: InputStream): InputStream

		companion object {
		@JvmStatic
		fun fromId(id: @BackupCodecId Byte): BackupCodec =
		when (id) {
		BackupCodecId.NO_OP -> BackupNoOpCodec()
		BackupCodecId.ZIP -> BackupZipCodec.BEST_COMPRESSION
		else -> throw IllegalArgumentException("Unknown codec id $id")
		}
		}
		}

		/** Codec without any additional encoding/decoding. */
		class BackupNoOpCodec : BackupCodec {
		override val id
		get() = BackupCodecId.NO_OP

		override val name
		get() = "N/A"

		override fun encode(outputStream: OutputStream) = outputStream

		override fun decode(inputStream: InputStream) = inputStream
		}

		/** Codec with ZIP compression. */
		class BackupZipCodec(
		private val compressionLevel: Int,
		override val name: String,
		) : BackupCodec {
		override val id
		get() = BackupCodecId.ZIP

		override fun encode(outputStream: OutputStream) =
		DeflaterOutputStream(outputStream, Deflater(compressionLevel))

		override fun decode(inputStream: InputStream) = InflaterInputStream(inputStream)

		companion object {
		val DEFAULT_COMPRESSION = BackupZipCodec(Deflater.DEFAULT_COMPRESSION, "ZipDefault")
		val BEST_COMPRESSION = BackupZipCodec(Deflater.BEST_COMPRESSION, "ZipBestCompression")
		val BEST_SPEED = BackupZipCodec(Deflater.BEST_SPEED, "ZipBestSpeed")
		}
		}

packages/SettingsLib/DataStore/src/com/android/settingslib/datastore/BackupRestoreEntity.kt

+7 −0

Original line number	Diff line number	Diff line
		@@ -35,6 +35,13 @@ interface BackupRestoreEntity {
		*/
		val key: String

		/**
		* Codec used to encode/decode the backup data.
		*
		* When it is null, the [BackupRestoreStorage.defaultCodec] will be used.
		*/
		fun codec(): BackupCodec? = null

		/**
		* Backs up the entity.
		*

packages/SettingsLib/DataStore/src/com/android/settingslib/datastore/BackupRestoreFileArchiver.kt

+22 −5

Original line number	Diff line number	Diff line
		@@ -41,6 +41,11 @@ internal class BackupRestoreFileArchiver(
		override fun createBackupRestoreEntities(): List<BackupRestoreEntity> =
		fileStorages.map { it.toBackupRestoreEntity() }

		override fun wrapBackupOutputStream(codec: BackupCodec, outputStream: OutputStream) =
		outputStream

		override fun wrapRestoreInputStream(codec: BackupCodec, inputStream: InputStream) = inputStream

		override fun restoreEntity(data: BackupDataInputStream) {
		val key = data.key
		val fileStorage = fileStorages.firstOrNull { it.storageFilePath == key }
		@@ -56,11 +61,19 @@ internal class BackupRestoreFileArchiver(
		File(context.dataDirCompat, key)
		}
		Log.i(LOG_TAG, "[$name] Restore ${data.size()} bytes for $key to $file")
		val inputStream = LimitedNoCloseInputStream(data)
		try {
		val codec = BackupCodec.fromId(inputStream.read().toByte())
		if (fileStorage != null && fileStorage.defaultCodec().id != codec.id) {
		Log.i(
		LOG_TAG,
		"[$name] $key different codec: ${codec.id}, ${fileStorage.defaultCodec().id}"
		)
		}
		file.parentFile?.mkdirs() // ensure parent folders are created
		val wrappedInputStream = wrapRestoreInputStream(data)
		file.outputStream().use { wrappedInputStream.copyTo(it) }
		Log.i(LOG_TAG, "[$name] $key restored")
		val wrappedInputStream = codec.decode(inputStream)
		val bytesCopied = file.outputStream().use { wrappedInputStream.copyTo(it) }
		Log.i(LOG_TAG, "[$name] $key restore $bytesCopied bytes with ${codec.name}")
		fileStorage?.onRestoreFinished(file)
		} catch (e: Exception) {
		Log.e(LOG_TAG, "[$name] Fail to restore $key", e)
		@@ -90,8 +103,12 @@ private fun BackupRestoreFileStorage.toBackupRestoreEntity() =
		Log.i(LOG_TAG, "[$name] $key not exist")
		return EntityBackupResult.DELETE
		}
		val wrappedOutputStream = wrapBackupOutputStream(outputStream)
		file.inputStream().use { it.copyTo(wrappedOutputStream) }
		val codec = codec() ?: defaultCodec()
		// MUST close to flush the data
		wrapBackupOutputStream(codec, outputStream).use { stream ->
		val bytesCopied = file.inputStream().use { it.copyTo(stream) }
		Log.i(LOG_TAG, "[$name] $key backup $bytesCopied bytes with ${codec.name}")
		}
		onBackupFinished(file)
		return EntityBackupResult.UPDATE
		}

packages/SettingsLib/DataStore/src/com/android/settingslib/datastore/BackupRestoreStorage.kt

+24 −6

Original line number	Diff line number	Diff line
		@@ -50,6 +50,9 @@ abstract class BackupRestoreStorage : BackupHelper {
		/** Entities to back up and restore. */
		abstract fun createBackupRestoreEntities(): List<BackupRestoreEntity>

		/** Default codec used to encode/decode the entity data. */
		open fun defaultCodec(): BackupCodec = BackupZipCodec.BEST_COMPRESSION

		override fun performBackup(
		oldState: ParcelFileDescriptor?,
		data: BackupDataOutput,
		@@ -64,9 +67,10 @@ abstract class BackupRestoreStorage : BackupHelper {
		for (entity in entities) {
		val key = entity.key
		val outputStream = ByteArrayOutputStream()
		val codec = entity.codec() ?: defaultCodec()
		val result =
		try {
		entity.backup(backupContext, wrapBackupOutputStream(outputStream))
		entity.backup(backupContext, wrapBackupOutputStream(codec, outputStream))
		} catch (exception: Exception) {
		Log.e(LOG_TAG, "[$name] Fail to backup entity $key", exception)
		continue
		@@ -94,8 +98,10 @@ abstract class BackupRestoreStorage : BackupHelper {
		/** Returns if backup is enabled. */
		open fun enableBackup(backupContext: BackupContext): Boolean = true

		fun wrapBackupOutputStream(outputStream: OutputStream): OutputStream {
		return outputStream
		open fun wrapBackupOutputStream(codec: BackupCodec, outputStream: OutputStream): OutputStream {
		// write a codec id header for safe restore
		outputStream.write(codec.id.toInt())
		return codec.encode(outputStream)
		}

		override fun restoreEntity(data: BackupDataInputStream) {
		@@ -111,8 +117,12 @@ abstract class BackupRestoreStorage : BackupHelper {
		}
		Log.i(LOG_TAG, "[$name] Restore $key: ${data.size()} bytes")
		val restoreContext = RestoreContext(key)
		val codec = entity.codec() ?: defaultCodec()
		try {
		entity.restore(restoreContext, wrapRestoreInputStream(data))
		entity.restore(
		restoreContext,
		wrapRestoreInputStream(codec, LimitedNoCloseInputStream(data))
		)
		} catch (exception: Exception) {
		Log.e(LOG_TAG, "[$name] Fail to restore entity $key", exception)
		}
		@@ -121,8 +131,16 @@ abstract class BackupRestoreStorage : BackupHelper {
		/** Returns if restore is enabled. */
		open fun enableRestore(): Boolean = true

		fun wrapRestoreInputStream(inputStream: BackupDataInputStream): InputStream {
		return LimitedNoCloseInputStream(inputStream)
		open fun wrapRestoreInputStream(
		codec: BackupCodec,
		inputStream: InputStream,
		): InputStream {
		// read the codec id first to check if it is expected codec
		val id = inputStream.read()
		val expectedId = codec.id.toInt()
		if (id == expectedId) return codec.decode(inputStream)
		Log.i(LOG_TAG, "Expect codec id $expectedId but got $id")
		return BackupCodec.fromId(id.toByte()).decode(inputStream)
		}

		override fun writeNewStateDescription(newState: ParcelFileDescriptor) {}