If the transport does not supply any user-facing configuration UI, it should * return {@code null} from this method. * * @return An Intent that can be passed to Context.startActivity() in order to * launch the transport's configuration UI. This method will return {@code null} * if the transport does not offer any user-facing configuration UI. */ public Intent configurationIntent() { return null; } /** * On demand, supply a one-line string that can be shown to the user that * describes the current backend destination. For example, a transport that * can potentially associate backup data with arbitrary user accounts should * include the name of the currently-active account here. * * @return A string describing the destination to which the transport is currently * sending data. This method should not return null. */ public String currentDestinationString() { throw new UnsupportedOperationException( "Transport currentDestinationString() not implemented"); } /** * Ask the transport for an Intent that can be used to launch a more detailed * secondary data management activity. For example, the configuration intent might * be one for allowing the user to select which account they wish to associate * their backups with, and the management intent might be one which presents a * UI for managing the data on the backend. * *
In the Settings UI, the configuration intent will typically be invoked * when the user taps on the preferences item labeled with the current * destination string, and the management intent will be placed in an overflow * menu labelled with the management label string. * *
If the transport does not supply any user-facing data management * UI, then it should return {@code null} from this method. * * @return An intent that can be passed to Context.startActivity() in order to * launch the transport's data-management UI. This method will return * {@code null} if the transport does not offer any user-facing data * management UI. */ public Intent dataManagementIntent() { return null; } /** * On demand, supply a short string that can be shown to the user as the label * on an overflow menu item used to invoked the data management UI. * * @return A string to be used as the label for the transport's data management * affordance. If the transport supplies a data management intent, this * method must not return {@code null}. */ public String dataManagementLabel() { throw new UnsupportedOperationException( "Transport dataManagementLabel() not implemented"); } /** * Ask the transport where, on local device storage, to keep backup state blobs. * This is per-transport so that mock transports used for testing can coexist with * "live" backup services without interfering with the live bookkeeping. The * returned string should be a name that is expected to be unambiguous among all * available backup transports; the name of the class implementing the transport * is a good choice. * * @return A unique name, suitable for use as a file or directory name, that the * Backup Manager could use to disambiguate state files associated with * different backup transports. */ public String transportDirName() { throw new UnsupportedOperationException( "Transport transportDirName() not implemented"); } // ------------------------------------------------------------------------------------ // Device-level operations common to both key/value and full-data storage /** * Initialize the server side storage for this device, erasing all stored data. * The transport may send the request immediately, or may buffer it. After * this is called, {@link #finishBackup} will be called to ensure the request * is sent and received successfully. * * @return One of {@link BackupTransport#TRANSPORT_OK} (OK so far) or * {@link BackupTransport#TRANSPORT_ERROR} (on network error or other failure). */ public int initializeDevice() { return BackupTransport.TRANSPORT_ERROR; } /** * Erase the given application's data from the backup destination. This clears * out the given package's data from the current backup set, making it as though * the app had never yet been backed up. After this is called, {@link finishBackup} * must be called to ensure that the operation is recorded successfully. * * @return the same error codes as {@link #performBackup}. */ public int clearBackupData(PackageInfo packageInfo) { return BackupTransport.TRANSPORT_ERROR; } /** * Finish sending application data to the backup destination. This must be * called after {@link #performBackup}, {@link #performFullBackup}, or {@link clearBackupData} * to ensure that all data is sent and the operation properly finalized. Only when this * method returns true can a backup be assumed to have succeeded. * * @return the same error codes as {@link #performBackup} or {@link #performFullBackup}. */ public int finishBackup() { return BackupTransport.TRANSPORT_ERROR; } // ------------------------------------------------------------------------------------ // Key/value incremental backup support interfaces /** * Verify that this is a suitable time for a key/value backup pass. This should return zero * if a backup is reasonable right now, some positive value otherwise. This method * will be called outside of the {@link #performBackup}/{@link #finishBackup} pair. * *
If this is not a suitable time for a backup, the transport should return a * backoff delay, in milliseconds, after which the Backup Manager should try again. * * @return Zero if this is a suitable time for a backup pass, or a positive time delay * in milliseconds to suggest deferring the backup pass for a while. */ public long requestBackupTime() { return 0; } /** * Send one application's key/value data update to the backup destination. The * transport may send the data immediately, or may buffer it. After this is called, * {@link #finishBackup} will be called to ensure the data is sent and recorded successfully. * * @param packageInfo The identity of the application whose data is being backed up. * This specifically includes the signature list for the package. * @param data The data stream that resulted from invoking the application's * BackupService.doBackup() method. This may be a pipe rather than a file on * persistent media, so it may not be seekable. * @param wipeAllFirst When true, all backed-up data for the current device/account * must be erased prior to the storage of the data provided here. The purpose of this * is to provide a guarantee that no stale data exists in the restore set when the * device begins providing incremental backups. * @return one of {@link BackupTransport#TRANSPORT_OK} (OK so far), * {@link BackupTransport#TRANSPORT_ERROR} (on network error or other failure), or * {@link BackupTransport#TRANSPORT_NOT_INITIALIZED} (if the backend dataset has * become lost due to inactivity purge or some other reason and needs re-initializing) */ public int performBackup(PackageInfo packageInfo, ParcelFileDescriptor inFd) { return BackupTransport.TRANSPORT_ERROR; } // ------------------------------------------------------------------------------------ // Key/value dataset restore interfaces /** * Get the set of all backups currently available over this transport. * * @return Descriptions of the set of restore images available for this device, * or null if an error occurred (the attempt should be rescheduled). **/ public RestoreSet[] getAvailableRestoreSets() { return null; } /** * Get the identifying token of the backup set currently being stored from * this device. This is used in the case of applications wishing to restore * their last-known-good data. * * @return A token that can be passed to {@link #startRestore}, or 0 if there * is no backup set available corresponding to the current device state. */ public long getCurrentRestoreSet() { return 0; } /** * Start restoring application data from backup. After calling this function, * alternate calls to {@link #nextRestorePackage} and {@link #nextRestoreData} * to walk through the actual application data. * * @param token A backup token as returned by {@link #getAvailableRestoreSets} * or {@link #getCurrentRestoreSet}. * @param packages List of applications to restore (if data is available). * Application data will be restored in the order given. * @return One of {@link BackupTransport#TRANSPORT_OK} (OK so far, call * {@link #nextRestorePackage}) or {@link BackupTransport#TRANSPORT_ERROR} * (an error occurred, the restore should be aborted and rescheduled). */ public int startRestore(long token, PackageInfo[] packages) { return BackupTransport.TRANSPORT_ERROR; } /** * Get the package name of the next application with data in the backup store, plus * a description of the structure of the restored archive: either TYPE_KEY_VALUE for * an original-API key/value dataset, or TYPE_FULL_STREAM for a tarball-type archive stream. * *
If the package name in the returned RestoreDescription object is the singleton * {@link RestoreDescription#NO_MORE_PACKAGES}, it indicates that no further data is available * in the current restore session: all packages described in startRestore() have been * processed. * *
If this method returns {@code null}, it means that a transport-level error has * occurred and the entire restore operation should be abandoned. * *
The OS may call {@link #nextRestorePackage()} multiple times * before calling either {@link #getRestoreData(ParcelFileDescriptor) getRestoreData()} * or {@link #getNextFullRestoreDataChunk(ParcelFileDescriptor) getNextFullRestoreDataChunk()}. * It does this when it has determined that it needs to skip restore of one or more * packages. The transport should not actually transfer any restore data for * the given package in response to {@link #nextRestorePackage()}, but rather wait * for an explicit request before doing so. * * @return A RestoreDescription object containing the name of one of the packages * supplied to {@link #startRestore} plus an indicator of the data type of that * restore data; or {@link RestoreDescription#NO_MORE_PACKAGES} to indicate that * no more packages can be restored in this session; or {@code null} to indicate * a transport-level error. */ public RestoreDescription nextRestorePackage() { return null; } /** * Get the data for the application returned by {@link #nextRestorePackage}, if that * method reported {@link RestoreDescription#TYPE_KEY_VALUE} as its delivery type. * If the package has only TYPE_FULL_STREAM data, then this method will return an * error. * * @param data An open, writable file into which the key/value backup data should be stored. * @return the same error codes as {@link #startRestore}. */ public int getRestoreData(ParcelFileDescriptor outFd) { return BackupTransport.TRANSPORT_ERROR; } /** * End a restore session (aborting any in-process data transfer as necessary), * freeing any resources and connections used during the restore process. */ public void finishRestore() { throw new UnsupportedOperationException( "Transport finishRestore() not implemented"); } // ------------------------------------------------------------------------------------ // Full backup interfaces /** * Verify that this is a suitable time for a full-data backup pass. This should return zero * if a backup is reasonable right now, some positive value otherwise. This method * will be called outside of the {@link #performFullBackup}/{@link #finishBackup} pair. * *
If this is not a suitable time for a backup, the transport should return a * backoff delay, in milliseconds, after which the Backup Manager should try again. * * @return Zero if this is a suitable time for a backup pass, or a positive time delay * in milliseconds to suggest deferring the backup pass for a while. * * @see #requestBackupTime() */ public long requestFullBackupTime() { return 0; } /** * Begin the process of sending an application's full-data archive to the backend. * The description of the package whose data will be delivered is provided, as well as * the socket file descriptor on which the transport will receive the data itself. * *
If the package is not eligible for backup, the transport should return * {@link BackupTransport#TRANSPORT_PACKAGE_REJECTED}. In this case the system will * simply proceed with the next candidate if any, or finish the full backup operation * if all apps have been processed. * *
After the transport returns {@link BackupTransport#TRANSPORT_OK} from this * method, the OS will proceed to call {@link #sendBackupData()} one or more times * to deliver the application's data as a streamed tarball. The transport should not * read() from the socket except as instructed to via the {@link #sendBackupData(int)} * method. * *
After all data has been delivered to the transport, the system will call * {@link #finishBackup()}. At this point the transport should commit the data to * its datastore, if appropriate, and close the socket that had been provided in * {@link #performFullBackup(PackageInfo, ParcelFileDescriptor)}. * *
If the transport returns TRANSPORT_OK from this method, then the * OS will always provide a matching call to {@link #finishBackup()} even if sending * data via {@link #sendBackupData(int)} failed at some point. * * @param targetPackage The package whose data is to follow. * @param socket The socket file descriptor through which the data will be provided. * If the transport returns {@link #TRANSPORT_PACKAGE_REJECTED} here, it must still * close this file descriptor now; otherwise it should be cached for use during * succeeding calls to {@link #sendBackupData(int)}, and closed in response to * {@link #finishBackup()}. * @return TRANSPORT_PACKAGE_REJECTED to indicate that the stated application is not * to be backed up; TRANSPORT_OK to indicate that the OS may proceed with delivering * backup data; TRANSPORT_ERROR to indicate a fatal error condition that precludes * performing a backup at this time. */ public int performFullBackup(PackageInfo targetPackage, ParcelFileDescriptor socket) { return BackupTransport.TRANSPORT_PACKAGE_REJECTED; } /** * Tells the transport to read {@code numBytes} bytes of data from the socket file * descriptor provided in the {@link #performFullBackup(PackageInfo, ParcelFileDescriptor)} * call, and deliver those bytes to the datastore. * * @param numBytes The number of bytes of tarball data available to be read from the * socket. * @return TRANSPORT_OK on successful processing of the data; TRANSPORT_ERROR to * indicate a fatal error situation. If an error is returned, the system will * call finishBackup() and stop attempting backups until after a backoff and retry * interval. */ public int sendBackupData(int numBytes) { return BackupTransport.TRANSPORT_ERROR; } /** * Tells the transport to cancel the currently-ongoing full backup operation. This * will happen between {@link #performFullBackup()} and {@link #finishBackup()} * if the OS needs to abort the backup operation for any reason, such as a crash in * the application undergoing backup. * *
When it receives this call, the transport should discard any partial archive * that it has stored so far. If possible it should also roll back to the previous * known-good archive in its datastore. * *
If the transport receives this callback, it will not receive a * call to {@link #finishBackup()}. It needs to tear down any ongoing backup state * here. */ public void cancelFullBackup() { throw new UnsupportedOperationException( "Transport cancelFullBackup() not implemented"); } // ------------------------------------------------------------------------------------ // Full restore interfaces /** * Ask the transport to provide data for the "current" package being restored. This * is the package that was just reported by {@link #nextRestorePackage()} as having * {@link RestoreDescription#TYPE_FULL_STREAM} data. * * The transport writes some data to the socket supplied to this call, and returns * the number of bytes written. The system will then read that many bytes and * stream them to the application's agent for restore, then will call this method again * to receive the next chunk of the archive. This sequence will be repeated until the * transport returns zero indicating that all of the package's data has been delivered * (or returns a negative value indicating some sort of hard error condition at the * transport level). * *
After this method returns zero, the system will then call * {@link #getNextFullRestorePackage()} to begin the restore process for the next * application, and the sequence begins again. * *
The transport should always close this socket when returning from this method. * Do not cache this socket across multiple calls or you may leak file descriptors. * * @param socket The file descriptor that the transport will use for delivering the * streamed archive. The transport must close this socket in all cases when returning * from this method. * @return {@link #NO_MORE_DATA} when no more data for the current package is available. * A positive value indicates the presence of that many bytes to be delivered to the app. * A value of zero indicates that no data was deliverable at this time, but the restore * is still running and the caller should retry. {@link #TRANSPORT_PACKAGE_REJECTED} * means that the current package's restore operation should be aborted, but that * the transport itself is still in a good state and so a multiple-package restore * sequence can still be continued. Any other negative return value is treated as a * fatal error condition that aborts all further restore operations on the current dataset. */ public int getNextFullRestoreDataChunk(ParcelFileDescriptor socket) { return 0; } /** * If the OS encounters an error while processing {@link RestoreDescription#TYPE_FULL_STREAM} * data for restore, it will invoke this method to tell the transport that it should * abandon the data download for the current package. The OS will then either call * {@link #nextRestorePackage()} again to move on to restoring the next package in the * set being iterated over, or will call {@link #finishRestore()} to shut down the restore * operation. * * @return {@link #TRANSPORT_OK} if the transport was successful in shutting down the * current stream cleanly, or {@link #TRANSPORT_ERROR} to indicate a serious * transport-level failure. If the transport reports an error here, the entire restore * operation will immediately be finished with no further attempts to restore app data. */ public int abortFullRestore() { return BackupTransport.TRANSPORT_OK; } /** * Bridge between the actual IBackupTransport implementation and the stable API. If the * binder interface needs to change, we use this layer to translate so that we can * (if appropriate) decouple those framework-side changes from the BackupTransport * implementations. */ class TransportImpl extends IBackupTransport.Stub { @Override public String name() throws RemoteException { return BackupTransport.this.name(); } @Override public Intent configurationIntent() throws RemoteException { return BackupTransport.this.configurationIntent(); } @Override public String currentDestinationString() throws RemoteException { return BackupTransport.this.currentDestinationString(); } @Override public Intent dataManagementIntent() { return BackupTransport.this.dataManagementIntent(); } @Override public String dataManagementLabel() { return BackupTransport.this.dataManagementLabel(); } @Override public String transportDirName() throws RemoteException { return BackupTransport.this.transportDirName(); } @Override public long requestBackupTime() throws RemoteException { return BackupTransport.this.requestBackupTime(); } @Override public int initializeDevice() throws RemoteException { return BackupTransport.this.initializeDevice(); } @Override public int performBackup(PackageInfo packageInfo, ParcelFileDescriptor inFd) throws RemoteException { return BackupTransport.this.performBackup(packageInfo, inFd); } @Override public int clearBackupData(PackageInfo packageInfo) throws RemoteException { return BackupTransport.this.clearBackupData(packageInfo); } @Override public int finishBackup() throws RemoteException { return BackupTransport.this.finishBackup(); } @Override public RestoreSet[] getAvailableRestoreSets() throws RemoteException { return BackupTransport.this.getAvailableRestoreSets(); } @Override public long getCurrentRestoreSet() throws RemoteException { return BackupTransport.this.getCurrentRestoreSet(); } @Override public int startRestore(long token, PackageInfo[] packages) throws RemoteException { return BackupTransport.this.startRestore(token, packages); } @Override public RestoreDescription nextRestorePackage() throws RemoteException { return BackupTransport.this.nextRestorePackage(); } @Override public int getRestoreData(ParcelFileDescriptor outFd) throws RemoteException { return BackupTransport.this.getRestoreData(outFd); } @Override public void finishRestore() throws RemoteException { BackupTransport.this.finishRestore(); } @Override public long requestFullBackupTime() throws RemoteException { return BackupTransport.this.requestFullBackupTime(); } @Override public int performFullBackup(PackageInfo targetPackage, ParcelFileDescriptor socket) throws RemoteException { return BackupTransport.this.performFullBackup(targetPackage, socket); } @Override public int sendBackupData(int numBytes) throws RemoteException { return BackupTransport.this.sendBackupData(numBytes); } @Override public void cancelFullBackup() throws RemoteException { BackupTransport.this.cancelFullBackup(); } @Override public int getNextFullRestoreDataChunk(ParcelFileDescriptor socket) { return BackupTransport.this.getNextFullRestoreDataChunk(socket); } @Override public int abortFullRestore() { return BackupTransport.this.abortFullRestore(); } } }