[DataStore] Support backup data state computation (3455f82a) · Commits · e / os / android_frameworks_base

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

+6 −18

Original line number	Diff line number	Diff line
		@@ -20,7 +20,6 @@ import android.app.backup.BackupAgent
		import android.app.backup.BackupDataOutput
		import android.app.backup.BackupHelper
		import android.os.Build
		import android.os.ParcelFileDescriptor
		import androidx.annotation.RequiresApi

		/**
		@@ -31,23 +30,8 @@ import androidx.annotation.RequiresApi
		*/
		class BackupContext
		internal constructor(
		/**
		* An open, read-only file descriptor pointing to the last backup state provided by the
		* application. May be null, in which case no prior state is being provided and the application
		* should perform a full backup.
		*
		* TODO: the state should support marshall/unmarshall for incremental back up.
		*/
		val oldState: ParcelFileDescriptor?,

		/** An open, read/write BackupDataOutput pointing to the backup data destination. */
		private val data: BackupDataOutput,

		/**
		* An open, read/write file descriptor pointing to an empty file. The application should record
		* the final backup.
		*/
		val newState: ParcelFileDescriptor,
		) {
		/**
		* The quota in bytes for the application's current backup operation.
		@@ -68,5 +52,9 @@ internal constructor(
		@RequiresApi(Build.VERSION_CODES.P) get() = data.transportFlags
		}

		/** Context for restore. */
		class RestoreContext(val key: String)
		/**
		* Context for restore.
		*
		* @param key Entity key
		*/
		class RestoreContext internal constructor(val key: String)

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

+9 −5

Original line number	Diff line number	Diff line
		@@ -18,11 +18,11 @@ package com.android.settingslib.datastore

		import android.app.backup.BackupDataInputStream
		import android.content.Context
		import android.os.ParcelFileDescriptor
		import android.util.Log
		import java.io.File
		import java.io.InputStream
		import java.io.OutputStream
		import java.util.zip.CheckedInputStream

		/**
		* File archiver to handle backup and restore for all the [BackupRestoreFileStorage] subclasses.
		@@ -62,8 +62,10 @@ internal class BackupRestoreFileArchiver(
		}
		Log.i(LOG_TAG, "[$name] Restore ${data.size()} bytes for $key to $file")
		val inputStream = LimitedNoCloseInputStream(data)
		checksum.reset()
		val checkedInputStream = CheckedInputStream(inputStream, checksum)
		try {
		val codec = BackupCodec.fromId(inputStream.read().toByte())
		val codec = BackupCodec.fromId(checkedInputStream.read().toByte())
		if (fileStorage != null && fileStorage.defaultCodec().id != codec.id) {
		Log.i(
		LOG_TAG,
		@@ -71,17 +73,19 @@ internal class BackupRestoreFileArchiver(
		)
		}
		file.parentFile?.mkdirs() // ensure parent folders are created
		val wrappedInputStream = codec.decode(inputStream)
		val wrappedInputStream = codec.decode(checkedInputStream)
		val bytesCopied = file.outputStream().use { wrappedInputStream.copyTo(it) }
		Log.i(LOG_TAG, "[$name] $key restore $bytesCopied bytes with ${codec.name}")
		fileStorage?.onRestoreFinished(file)
		entityStates[key] = checksum.value
		} catch (e: Exception) {
		Log.e(LOG_TAG, "[$name] Fail to restore $key", e)
		}
		}

		override fun writeNewStateDescription(newState: ParcelFileDescriptor) =
		fileStorages.forEach { it.writeNewStateDescription(newState) }
		override fun onRestoreFinished() {
		fileStorages.forEach { it.onRestoreFinished() }
		}
		}

		private fun BackupRestoreFileStorage.toBackupRestoreEntity() =

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

+110 −12

Original line number	Diff line number	Diff line
		@@ -22,11 +22,20 @@ import android.app.backup.BackupDataOutput
		import android.app.backup.BackupHelper
		import android.os.ParcelFileDescriptor
		import android.util.Log
		import androidx.collection.MutableScatterMap
		import com.google.common.io.ByteStreams
		import java.io.ByteArrayOutputStream
		import java.io.DataInputStream
		import java.io.DataOutputStream
		import java.io.EOFException
		import java.io.FileInputStream
		import java.io.FileOutputStream
		import java.io.FilterInputStream
		import java.io.InputStream
		import java.io.OutputStream
		import java.util.zip.CRC32
		import java.util.zip.CheckedInputStream
		import java.util.zip.CheckedOutputStream

		internal const val LOG_TAG = "BackupRestoreStorage"

		@@ -47,6 +56,20 @@ abstract class BackupRestoreStorage : BackupHelper {

		private val entities: List<BackupRestoreEntity> by lazy { createBackupRestoreEntities() }

		/**
		* Checksum of the data.
		*
		* Always call [java.util.zip.Checksum.reset] before using it.
		*/
		protected val checksum = CRC32()

		/**
		* Entity states represented by checksum.
		*
		* Map key is the entity key, map value is the checksum of backup data.
		*/
		protected val entityStates = MutableScatterMap<String, Long>()

		/** Entities to back up and restore. */
		abstract fun createBackupRestoreEntities(): List<BackupRestoreEntity>

		@@ -58,7 +81,8 @@ abstract class BackupRestoreStorage : BackupHelper {
		data: BackupDataOutput,
		newState: ParcelFileDescriptor,
		) {
		val backupContext = BackupContext(oldState, data, newState)
		oldState.readEntityStates(entityStates)
		val backupContext = BackupContext(data)
		if (!enableBackup(backupContext)) {
		Log.i(LOG_TAG, "[$name] Backup disabled")
		return
		@@ -67,34 +91,50 @@ abstract class BackupRestoreStorage : BackupHelper {
		for (entity in entities) {
		val key = entity.key
		val outputStream = ByteArrayOutputStream()
		checksum.reset()
		val checkedOutputStream = CheckedOutputStream(outputStream, checksum)
		val codec = entity.codec() ?: defaultCodec()
		val result =
		try {
		entity.backup(backupContext, wrapBackupOutputStream(codec, outputStream))
		entity.backup(backupContext, wrapBackupOutputStream(codec, checkedOutputStream))
		} catch (exception: Exception) {
		Log.e(LOG_TAG, "[$name] Fail to backup entity $key", exception)
		continue
		}
		when (result) {
		EntityBackupResult.UPDATE -> {
		if (updateEntityState(key)) {
		val payload = outputStream.toByteArray()
		val size = payload.size
		data.writeEntityHeader(key, size)
		data.writeEntityData(payload, size)
		Log.i(LOG_TAG, "[$name] Backup entity $key: $size bytes")
		} else {
		Log.i(
		LOG_TAG,
		"[$name] Backup entity $key unchanged: ${outputStream.size()} bytes"
		)
		}
		}
		EntityBackupResult.INTACT -> {
		Log.i(LOG_TAG, "[$name] Backup entity $key intact")
		}
		EntityBackupResult.DELETE -> {
		entityStates.remove(key)
		data.writeEntityHeader(key, -1)
		Log.i(LOG_TAG, "[$name] Backup entity $key deleted")
		}
		}
		}
		newState.writeEntityStates(entityStates)
		Log.i(LOG_TAG, "[$name] Backup end")
		}

		private fun updateEntityState(key: String): Boolean {
		val value = checksum.value
		return entityStates.put(key, value) != value
		}

		/** Returns if backup is enabled. */
		open fun enableBackup(backupContext: BackupContext): Boolean = true

		@@ -118,11 +158,12 @@ abstract class BackupRestoreStorage : BackupHelper {
		Log.i(LOG_TAG, "[$name] Restore $key: ${data.size()} bytes")
		val restoreContext = RestoreContext(key)
		val codec = entity.codec() ?: defaultCodec()
		val inputStream = LimitedNoCloseInputStream(data)
		checksum.reset()
		val checkedInputStream = CheckedInputStream(inputStream, checksum)
		try {
		entity.restore(
		restoreContext,
		wrapRestoreInputStream(codec, LimitedNoCloseInputStream(data))
		)
		entity.restore(restoreContext, wrapRestoreInputStream(codec, checkedInputStream))
		entityStates[key] = checksum.value
		} catch (exception: Exception) {
		Log.e(LOG_TAG, "[$name] Fail to restore entity $key", exception)
		}
		@@ -143,7 +184,64 @@ abstract class BackupRestoreStorage : BackupHelper {
		return BackupCodec.fromId(id.toByte()).decode(inputStream)
		}

		override fun writeNewStateDescription(newState: ParcelFileDescriptor) {}
		final override fun writeNewStateDescription(newState: ParcelFileDescriptor) {
		newState.writeEntityStates(entityStates)
		onRestoreFinished()
		}

		/** Callbacks when restore finished. */
		open fun onRestoreFinished() {}

		private fun ParcelFileDescriptor?.readEntityStates(state: MutableScatterMap<String, Long>) {
		state.clear()
		if (this == null) return
		// do not close the streams
		val fileInputStream = FileInputStream(fileDescriptor)
		val dataInputStream = DataInputStream(fileInputStream)
		try {
		val version = dataInputStream.readByte()
		if (version != STATE_VERSION) {
		Log.w(
		LOG_TAG,
		"[$name] Unexpected state version, read:$version, expected:$STATE_VERSION"
		)
		return
		}
		var count = dataInputStream.readInt()
		while (count-- > 0) {
		val key = dataInputStream.readUTF()
		val checksum = dataInputStream.readLong()
		state[key] = checksum
		}
		} catch (exception: Exception) {
		if (exception is EOFException) {
		Log.d(LOG_TAG, "[$name] Hit EOF when read state file")
		} else {
		Log.e(LOG_TAG, "[$name] Fail to read state file", exception)
		}
		state.clear()
		}
		}

		private fun ParcelFileDescriptor.writeEntityStates(state: MutableScatterMap<String, Long>) {
		// do not close the streams
		val fileOutputStream = FileOutputStream(fileDescriptor)
		val dataOutputStream = DataOutputStream(fileOutputStream)
		try {
		dataOutputStream.writeByte(STATE_VERSION.toInt())
		dataOutputStream.writeInt(state.size)
		state.forEach { key, value ->
		dataOutputStream.writeUTF(key)
		dataOutputStream.writeLong(value)
		}
		} catch (exception: Exception) {
		Log.e(LOG_TAG, "[$name] Fail to write state file", exception)
		}
		}

		companion object {
		private const val STATE_VERSION: Byte = 0
		}
		}

		/**