Provide stable concrete wrapper for backup transport API

This initial version is a simple pass-through of the existing
IBackupTransport AIDL definition.

Change-Id: I0f6c9ffc7101f82127ab61ba6cba9f5003af6a0c

1 files changed, 334 insertions, 0 deletions

diff --git a/core/java/android/app/backup/BackupTransport.java b/core/java/android/app/backup/BackupTransport.java
new file mode 100644
index 0000000..da5cb10
--- /dev/null
+++ b/core/java/android/app/backup/BackupTransport.java
@@ -0,0 +1,334 @@
+/*
+ * Copyright (C) 2014 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 android.app.backup;
+
+import android.content.Intent;
+import android.content.pm.PackageInfo;
+import android.os.IBinder;
+import android.os.ParcelFileDescriptor;
+import android.os.RemoteException;
+
+import com.android.internal.backup.BackupConstants;
+import com.android.internal.backup.IBackupTransport;
+
+/**
+ * Concrete class that provides a stable-API bridge between IBackupTransport
+ * and its implementations.
+ *
+ * @hide
+ */
+public class BackupTransport {
+    IBackupTransport mBinderImpl = new TransportImpl();
+    /** @hide */
+    public IBinder getBinder() {
+        return mBinderImpl.asBinder();
+    }
+
+    // ------------------------------------------------------------------------------------
+    // Transport self-description and general configuration interfaces
+    //
+
+    /**
+     * Ask the transport for the name under which it should be registered.  This will
+     * typically be its host service's component name, but need not be.
+     */
+    public String name() {
+        throw new UnsupportedOperationException("Transport name() not implemented");
+    }
+
+    /**
+     * Ask the transport for an Intent that can be used to launch any internal
+     * configuration Activity that it wishes to present.  For example, the transport
+     * may offer a UI for allowing the user to supply login credentials for the
+     * transport's off-device backend.
+     *
+     * If the transport does not supply any user-facing configuration UI, it should
+     * return 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 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 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");
+    }
+
+    // ------------------------------------------------------------------------------------
+    // Key/value incremental backup support interfaces
+
+    /**
+     * Verify that this is a suitable time for a 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.
+     *
+     * <p>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;
+    }
+
+    /**
+     * 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 BackupConstants#TRANSPORT_OK} (OK so far) or
+     *   {@link BackupConstants#TRANSPORT_ERROR} (on network error or other failure).
+     */
+    public int initializeDevice() {
+        return BackupConstants.TRANSPORT_ERROR;
+    }
+
+    /**
+     * 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, <i>all</i> 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 BackupConstants#TRANSPORT_OK} (OK so far),
+     *  {@link BackupConstants#TRANSPORT_ERROR} (on network error or other failure), or
+     *  {@link BackupConstants#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 BackupConstants.TRANSPORT_ERROR;
+    }
+
+    /**
+     * Erase the give 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 BackupConstants.TRANSPORT_ERROR;
+    }
+
+    /**
+     * Finish sending application data to the backup destination.  This must be
+     * called after {@link #performBackup} or {@link clearBackupData} to ensure that
+     * all data is sent.  Only when this method returns true can a backup be assumed
+     * to have succeeded.
+     *
+     * @return the same error codes as {@link #performBackup}.
+     */
+    public int finishBackup() {
+        return BackupConstants.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 BackupConstants#TRANSPORT_OK} (OK so far, call
+     *   {@link #nextRestorePackage}) or {@link BackupConstants#TRANSPORT_ERROR}
+     *   (an error occurred, the restore should be aborted and rescheduled).
+     */
+    public int startRestore(long token, PackageInfo[] packages) {
+        return BackupConstants.TRANSPORT_ERROR;
+    }
+
+    /**
+     * Get the package name of the next application with data in the backup store.
+     *
+     * @return The name of one of the packages supplied to {@link #startRestore},
+     *   or "" (the empty string) if no more backup data is available,
+     *   or null if an error occurred (the restore should be aborted and rescheduled).
+     */
+    public String nextRestorePackage() {
+        return null;
+    }
+
+    /**
+     * Get the data for the application returned by {@link #nextRestorePackage}.
+     * @param data An open, writable file into which the backup data should be stored.
+     * @return the same error codes as {@link #startRestore}.
+     */
+    public int getRestoreData(ParcelFileDescriptor outFd) {
+        return BackupConstants.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");
+    }
+
+    /**
+     * 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 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 String 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();
+        }
+    }
+}