Make IBackupTransport AIDL async

Make the transport AIDL async and introduce a callback AIDL for passing
back results. A follow-up CL will implement the client-side portion of
the callback class and update BackupTransportClient to use it.

Bug: 202716271
Test: m -j
Change-Id: I79cb376bd2a805bf2739470a3f538207ae6bd9a0

3 files changed, 323 insertions, 155 deletions

diff --git a/core/java/android/app/backup/BackupTransport.java b/core/java/android/app/backup/BackupTransport.java
index 567eb4a68a1d..9bb048d7a75f 100644
--- a/core/java/android/app/backup/BackupTransport.java
+++ b/core/java/android/app/backup/BackupTransport.java
@@ -25,6 +25,11 @@ import android.os.ParcelFileDescriptor;
 import android.os.RemoteException;
 
 import com.android.internal.backup.IBackupTransport;
+import com.android.internal.backup.ITransportStatusCallback;
+import com.android.internal.infra.AndroidFuture;
+
+import java.util.Arrays;
+import java.util.List;
 
 /**
  * Concrete class that provides a stable-API bridge between IBackupTransport
@@ -659,141 +664,185 @@ public class BackupTransport {
     class TransportImpl extends IBackupTransport.Stub {
 
         @Override
-        public String name() throws RemoteException {
-            return BackupTransport.this.name();
+        public void name(AndroidFuture<String> resultFuture) throws RemoteException {
+            String result = BackupTransport.this.name();
+            resultFuture.complete(result);
         }
 
         @Override
-        public Intent configurationIntent() throws RemoteException {
-            return BackupTransport.this.configurationIntent();
+        public void configurationIntent(AndroidFuture<Intent> resultFuture)
+                throws RemoteException {
+            Intent result = BackupTransport.this.configurationIntent();
+            resultFuture.complete(result);
         }
 
         @Override
-        public String currentDestinationString() throws RemoteException {
-            return BackupTransport.this.currentDestinationString();
+        public void currentDestinationString(AndroidFuture<String> resultFuture)
+                throws RemoteException {
+            String result = BackupTransport.this.currentDestinationString();
+            resultFuture.complete(result);
         }
 
         @Override
-        public Intent dataManagementIntent() {
-            return BackupTransport.this.dataManagementIntent();
+        public void dataManagementIntent(AndroidFuture<Intent> resultFuture)
+                throws RemoteException {
+            Intent result = BackupTransport.this.dataManagementIntent();
+            resultFuture.complete(result);
         }
 
         @Override
-        public CharSequence dataManagementIntentLabel() {
-            return BackupTransport.this.dataManagementIntentLabel();
+        public void dataManagementIntentLabel(AndroidFuture<CharSequence> resultFuture)
+                throws RemoteException {
+            CharSequence result = BackupTransport.this.dataManagementIntentLabel();
+            resultFuture.complete(result);
         }
 
         @Override
-        public String transportDirName() throws RemoteException {
-            return BackupTransport.this.transportDirName();
+        public void transportDirName(AndroidFuture<String> resultFuture) throws RemoteException {
+            String result = BackupTransport.this.transportDirName();
+            resultFuture.complete(result);
         }
 
         @Override
-        public long requestBackupTime() throws RemoteException {
-            return BackupTransport.this.requestBackupTime();
+        public void requestBackupTime(AndroidFuture<Long> resultFuture) throws RemoteException {
+            long result = BackupTransport.this.requestBackupTime();
+            resultFuture.complete(result);
         }
 
         @Override
-        public int initializeDevice() throws RemoteException {
-            return BackupTransport.this.initializeDevice();
+        public void initializeDevice(ITransportStatusCallback callback) throws RemoteException {
+            int result = BackupTransport.this.initializeDevice();
+            callback.onOperationCompleteWithStatus(result);
         }
 
         @Override
-        public int performBackup(PackageInfo packageInfo, ParcelFileDescriptor inFd, int flags)
-                throws RemoteException {
-            return BackupTransport.this.performBackup(packageInfo, inFd, flags);
+        public void performBackup(PackageInfo packageInfo, ParcelFileDescriptor inFd, int flags,
+                ITransportStatusCallback callback) throws RemoteException {
+            int result = BackupTransport.this.performBackup(packageInfo, inFd, flags);
+            callback.onOperationCompleteWithStatus(result);
         }
 
         @Override
-        public int clearBackupData(PackageInfo packageInfo) throws RemoteException {
-            return BackupTransport.this.clearBackupData(packageInfo);
+        public void clearBackupData(PackageInfo packageInfo, ITransportStatusCallback callback)
+                throws RemoteException {
+            int result = BackupTransport.this.clearBackupData(packageInfo);
+            callback.onOperationCompleteWithStatus(result);
         }
 
         @Override
-        public int finishBackup() throws RemoteException {
-            return BackupTransport.this.finishBackup();
+        public void finishBackup(ITransportStatusCallback callback) throws RemoteException {
+            int result = BackupTransport.this.finishBackup();
+            callback.onOperationCompleteWithStatus(result);
         }
 
         @Override
-        public RestoreSet[] getAvailableRestoreSets() throws RemoteException {
-            return BackupTransport.this.getAvailableRestoreSets();
+        public void getAvailableRestoreSets(AndroidFuture<List<RestoreSet>> resultFuture)
+                throws RemoteException {
+            RestoreSet[] result = BackupTransport.this.getAvailableRestoreSets();
+            resultFuture.complete(Arrays.asList(result));
         }
 
         @Override
-        public long getCurrentRestoreSet() throws RemoteException {
-            return BackupTransport.this.getCurrentRestoreSet();
+        public void getCurrentRestoreSet(AndroidFuture<Long> resultFuture)
+                throws RemoteException {
+            long result = BackupTransport.this.getCurrentRestoreSet();
+            resultFuture.complete(result);
         }
 
         @Override
-        public int startRestore(long token, PackageInfo[] packages) throws RemoteException {
-            return BackupTransport.this.startRestore(token, packages);
+        public void startRestore(long token, PackageInfo[] packages,
+                ITransportStatusCallback callback)  throws RemoteException {
+            int result = BackupTransport.this.startRestore(token, packages);
+            callback.onOperationCompleteWithStatus(result);
         }
 
         @Override
-        public RestoreDescription nextRestorePackage() throws RemoteException {
-            return BackupTransport.this.nextRestorePackage();
+        public void nextRestorePackage(AndroidFuture<RestoreDescription> resultFuture)
+                throws RemoteException {
+            RestoreDescription result = BackupTransport.this.nextRestorePackage();
+            resultFuture.complete(result);
         }
 
         @Override
-        public int getRestoreData(ParcelFileDescriptor outFd) throws RemoteException {
-            return BackupTransport.this.getRestoreData(outFd);
+        public void getRestoreData(ParcelFileDescriptor outFd,
+                ITransportStatusCallback callback) throws RemoteException {
+            int result = BackupTransport.this.getRestoreData(outFd);
+            callback.onOperationCompleteWithStatus(result);
         }
 
         @Override
-        public void finishRestore() throws RemoteException {
+        public void finishRestore(ITransportStatusCallback callback)
+                throws RemoteException {
             BackupTransport.this.finishRestore();
+            callback.onOperationComplete();
         }
 
         @Override
-        public long requestFullBackupTime() throws RemoteException {
-            return BackupTransport.this.requestFullBackupTime();
+        public void requestFullBackupTime(AndroidFuture<Long> resultFuture)
+                throws RemoteException {
+            long result = BackupTransport.this.requestFullBackupTime();
+            resultFuture.complete(result);
         }
 
         @Override
-        public int performFullBackup(PackageInfo targetPackage, ParcelFileDescriptor socket,
-                int flags) throws RemoteException {
-            return BackupTransport.this.performFullBackup(targetPackage, socket, flags);
+        public void performFullBackup(PackageInfo targetPackage, ParcelFileDescriptor socket,
+                int flags, ITransportStatusCallback callback) throws RemoteException {
+            int result = BackupTransport.this.performFullBackup(targetPackage, socket, flags);
+            callback.onOperationCompleteWithStatus(result);
         }
 
         @Override
-        public int checkFullBackupSize(long size) {
-            return BackupTransport.this.checkFullBackupSize(size);
+        public void checkFullBackupSize(long size, ITransportStatusCallback callback)
+                throws RemoteException {
+            int result = BackupTransport.this.checkFullBackupSize(size);
+            callback.onOperationCompleteWithStatus(result);
         }
 
         @Override
-        public int sendBackupData(int numBytes) throws RemoteException {
-            return BackupTransport.this.sendBackupData(numBytes);
+        public void sendBackupData(int numBytes, ITransportStatusCallback callback)
+                throws RemoteException {
+            int result = BackupTransport.this.sendBackupData(numBytes);
+            callback.onOperationCompleteWithStatus(result);
         }
 
         @Override
-        public void cancelFullBackup() throws RemoteException {
+        public void cancelFullBackup(ITransportStatusCallback callback) throws RemoteException {
             BackupTransport.this.cancelFullBackup();
+            callback.onOperationComplete();
         }
 
         @Override
-        public boolean isAppEligibleForBackup(PackageInfo targetPackage, boolean isFullBackup)
-                throws RemoteException {
-            return BackupTransport.this.isAppEligibleForBackup(targetPackage, isFullBackup);
+        public void isAppEligibleForBackup(PackageInfo targetPackage, boolean isFullBackup,
+                AndroidFuture<Boolean> resultFuture) throws RemoteException {
+            boolean result = BackupTransport.this.isAppEligibleForBackup(targetPackage,
+                    isFullBackup);
+            resultFuture.complete(result);
         }
 
         @Override
-        public long getBackupQuota(String packageName, boolean isFullBackup) {
-            return BackupTransport.this.getBackupQuota(packageName, isFullBackup);
+        public void getBackupQuota(String packageName, boolean isFullBackup,
+                AndroidFuture<Long> resultFuture) throws RemoteException {
+            long result = BackupTransport.this.getBackupQuota(packageName, isFullBackup);
+            resultFuture.complete(result);
         }
 
         @Override
-        public int getTransportFlags() {
-            return BackupTransport.this.getTransportFlags();
+        public void getTransportFlags(AndroidFuture<Integer> resultFuture) throws RemoteException {
+            int result = BackupTransport.this.getTransportFlags();
+            resultFuture.complete(result);
         }
 
         @Override
-        public int getNextFullRestoreDataChunk(ParcelFileDescriptor socket) {
-            return BackupTransport.this.getNextFullRestoreDataChunk(socket);
+        public void getNextFullRestoreDataChunk(ParcelFileDescriptor socket,
+                ITransportStatusCallback callback) throws RemoteException {
+            int result = BackupTransport.this.getNextFullRestoreDataChunk(socket);
+            callback.onOperationCompleteWithStatus(result);
         }
 
         @Override
-        public int abortFullRestore() {
-            return BackupTransport.this.abortFullRestore();
+        public void abortFullRestore(ITransportStatusCallback callback) throws RemoteException {
+            int result = BackupTransport.this.abortFullRestore();
+            callback.onOperationCompleteWithStatus(result);
         }
     }
 }
diff --git a/core/java/com/android/internal/backup/IBackupTransport.aidl b/core/java/com/android/internal/backup/IBackupTransport.aidl
index c9baf004d798..f09e176beea0 100644
--- a/core/java/com/android/internal/backup/IBackupTransport.aidl
+++ b/core/java/com/android/internal/backup/IBackupTransport.aidl
@@ -22,39 +22,46 @@ import android.content.Intent;
 import android.content.pm.PackageInfo;
 import android.os.ParcelFileDescriptor;
 
+import com.android.internal.backup.ITransportStatusCallback;
+import com.android.internal.infra.AndroidFuture;
+
 /** {@hide} */
-interface IBackupTransport {
+oneway interface IBackupTransport {
     /**
-     * Ask the transport for the name under which it should be registered.  This will
+     * Ask the transport for the String name under which it should be registered.  This will
      * typically be its host service's component name, but need not be.
+     *
+     * @param resultFuture an {@link AndroidFuture} that is completed with the {@code String} name
+     * of the transport.
+     */
+    void name(in AndroidFuture<String> result);
+
+    /**
+     * 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.
+     *
+     * @param resultFuture an {@link AndroidFuture} that is completed with an {@code Intent} that
+     *        can be passed to Context.startActivity() in order to launch the transport's
+     *        configuration UI.  This future will complete with null if the transport does not
+     *        offer any user-facing configuration UI.
+     */
+    void configurationIntent(in AndroidFuture<Intent> resultFuture);
+
+    /**
+     * Ask the transport for 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.
+     *
+     * @param resultFuture an {@link AndroidFuture} that is completed with a {@code String}
+     *        describing the destination to which the transport is currently sending data.
      */
-    String name();
-
-	/**
-	 * 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.
-	 */
-	Intent configurationIntent();
-
-	/**
-	 * 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.
-	 */
-	String currentDestinationString();
+    void currentDestinationString(in AndroidFuture<String> resultFuture);
 
     /**
      * Ask the transport for an Intent that can be used to launch a more detailed
@@ -71,22 +78,23 @@ interface IBackupTransport {
      * <p>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.
+     * @param resultFuture an {@link AndroidFuture} that is completed with an {@code Intent} that
+     *        can be passed to Context.startActivity() in order to launch the transport's
+     *        data-management UI. The callback will supply {@code null} if the transport does not
+     *        offer any user-facing data management UI.
      */
-    Intent dataManagementIntent();
+    void dataManagementIntent(in AndroidFuture<Intent> resultFuture);
 
     /**
-     * On demand, supply a short {@link CharSequence} that can be shown to the user as the label on
-     * an overflow menu item used to invoke the data management UI.
+     * Ask the transport for a short {@link CharSequence} that can be shown to the user as the label
+     * on an overflow menu item used to invoke the data management UI.
      *
-     * @return A {@link CharSequence} 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}.
+     * @param resultFuture an {@link AndroidFuture} that is completed with a {@code CharSequence}
+     *        to be used as the label for the transport's data management affordance.  If the
+     *        transport supplies a data management Intent via {@link #dataManagementIntent},
+     *        this method must not return {@code null}.
      */
-    CharSequence dataManagementIntentLabel();
+    void dataManagementIntentLabel(in AndroidFuture<CharSequence> resultFuture);
 
     /**
      * Ask the transport where, on local device storage, to keep backup state blobs.
@@ -96,11 +104,11 @@ interface IBackupTransport {
      * available backup transports; the name of the class implementing the transport
      * is a good choice.  This MUST be constant.
      *
-     * @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.
+     * @param resultFuture an {@link AndroidFuture} that is completed with a unique {@code String}
+     *        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.
      */
-    String transportDirName();
+    void transportDirName(in AndroidFuture<String> resultFuture);
 
     /**
      * Verify that this is a suitable time for a backup pass.  This should return zero
@@ -110,10 +118,11 @@ interface IBackupTransport {
      * <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.
+     * @param resultFuture an {@link AndroidFuture} that is completed with {@code int}: 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.
      */
-    long requestBackupTime();
+    void requestBackupTime(in AndroidFuture<long> resultFuture);
 
     /**
      * Initialize the server side storage for this device, erasing all stored data.
@@ -121,10 +130,11 @@ interface IBackupTransport {
      * this is called, {@link #finishBackup} must 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).
+     * @param callback a callback that is completed with a {@code int} which is one
+     *        of {@link BackupConstants#TRANSPORT_OK} (OK so far) or
+     *        {@link BackupConstants#TRANSPORT_ERROR} (on network error or other failure).
      */
-    int initializeDevice();
+    void initializeDevice(in ITransportStatusCallback callback);
 
     /**
      * Send one application's data to the backup destination.  The transport may send
@@ -137,12 +147,14 @@ interface IBackupTransport {
      *   BackupService.doBackup() method.  This may be a pipe rather than a file on
      *   persistent media, so it may not be seekable.
      * @param flags Some of {@link BackupTransport#FLAG_USER_INITIATED}.
-     * @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 inactive expiry or some other reason and needs re-initializing)
+     * @param callback a callback that is completed with a {@code int} which is 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 inactive expiry or some other reason and
+     *  needs re-initializing).
      */
-    int performBackup(in PackageInfo packageInfo, in ParcelFileDescriptor inFd, int flags);
+    void performBackup(in PackageInfo packageInfo, in ParcelFileDescriptor inFd, int flags,
+            in ITransportStatusCallback callback);
 
     /**
      * Erase the give application's data from the backup destination.  This clears
@@ -150,9 +162,10 @@ interface IBackupTransport {
      * 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}.
+     * @param callback a callback that is completed with the same error codes as
+     *        {@link #performBackup}.
      */
-    int clearBackupData(in PackageInfo packageInfo);
+    void clearBackupData(in PackageInfo packageInfo, in ITransportStatusCallback callback);
 
     /**
      * Finish sending application data to the backup destination.  This must be
@@ -160,27 +173,30 @@ interface IBackupTransport {
      * 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}.
+     * @param callback a callback that is completed with the same error codes as
+     *        {@link #performBackup}.
      */
-    int finishBackup();
+    void finishBackup(in ITransportStatusCallback callback);
 
     /**
      * 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).
+     * @param resultFuture an {@link AndroidFuture} that is completed with {@code List<RestoreSet>}:
+     *        the descriptions of a set of restore images available for this device, or null if an
+     *        error occurred (the attempt should be rescheduled).
      **/
-    RestoreSet[] getAvailableRestoreSets();
+    void getAvailableRestoreSets(in AndroidFuture<List<RestoreSet>> resultFuture);
 
     /**
      * 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.
+     * @param resultFuture an {@link AndroidFuture} that is completed with a {@code long}: a token
+     *        that can be passed to {@link #startRestore}, or 0 if there is no backup set available
+     *        corresponding to the current device state.
      */
-    long getCurrentRestoreSet();
+    void getCurrentRestoreSet(in AndroidFuture<long> resultFuture);
 
     /**
      * Start restoring application data from backup.  After calling this function,
@@ -191,11 +207,12 @@ interface IBackupTransport {
      *   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).
+     * @param callback a callback that is completed with 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).
      */
-    int startRestore(long token, in PackageInfo[] packages);
+    void startRestore(long token, in PackageInfo[] packages, in ITransportStatusCallback callback);
 
     /**
      * Get the package name of the next application with data in the backup store, plus
@@ -210,34 +227,95 @@ interface IBackupTransport {
      * <p>If this method returns {@code null}, it means that a transport-level error has
      * occurred and the entire restore operation should be abandoned.
      *
-     * @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.
+     * @param resultFuture an {@link AndroidFuture} that is completed with a
+     *   {@link 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.
      */
-    RestoreDescription nextRestorePackage();
+    void nextRestorePackage(in AndroidFuture<RestoreDescription> resultFuture);
 
     /**
      * 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}.
+     *
+     * @param callback a callback that is completed with the same error codes as
+     *        {@link #startRestore}.
      */
-    int getRestoreData(in ParcelFileDescriptor outFd);
+    void getRestoreData(in ParcelFileDescriptor outFd, in ITransportStatusCallback callback);
 
     /**
      * End a restore session (aborting any in-process data transfer as necessary),
      * freeing any resources and connections used during the restore process.
+     *
+     * @param callback a callback to signal that restore has been finished on transport side.
      */
-    void finishRestore();
+    void finishRestore(in ITransportStatusCallback callback);
 
     // full backup stuff
 
-    long requestFullBackupTime();
-    int performFullBackup(in PackageInfo targetPackage, in ParcelFileDescriptor socket, int flags);
-    int checkFullBackupSize(long size);
-    int sendBackupData(int numBytes);
-    void cancelFullBackup();
+    /**
+     * Verify that this is a suitable time for a full-data backup pass.
+     *
+     * @param resultFuture an {@link AndroidFuture} that is completed with {@code long}: 0 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.
+     */
+    void requestFullBackupTime(in AndroidFuture<long> resultFuture);
+
+    /**
+     * Begin the process of sending an application's full-data archive to the backend.
+     *
+     * @param targetPackage The package whose data is to follow.
+     * @param socket The socket file descriptor through which the data will be provided.
+     * @param flags {@link BackupTransport#FLAG_USER_INITIATED} or 0.
+     * @param callback callback to return a {@code int} which is one of:
+     *        {@link BackupTransport#TRANSPORT_PACKAGE_REJECTED} to indicate that the stated
+     *        application is not to be backed up; {@link BackupTransport#TRANSPORT_OK} to indicate
+     *        that the OS may proceed with delivering backup data;
+     *        {@link BackupTransport#TRANSPORT_ERROR to indicate a fatal error condition that
+     *        precludes performing a backup at this time.
+     */
+    void performFullBackup(in PackageInfo targetPackage, in ParcelFileDescriptor socket, int flags,
+            in ITransportStatusCallback callback);
+
+    /**
+     * Called after {@link #performFullBackup} to make sure that the transport is willing to
+     * handle a full-data backup operation of the specified size on the current package.
+     *
+     * @param size The estimated size of the full-data payload for this app.  This includes
+     *         manifest and archive format overhead, but is not guaranteed to be precise.
+     * @param callback a callback that is completed with a {@code int} which is
+     *        one of: {@link BackupTransport#TRANSPORT_OK} if the platform is to proceed with the
+     *        full-data {@link BackupTransport#TRANSPORT_PACKAGE_REJECTED} if the proposed payload
+     *        size is backup, too large for the transport to handle, or
+     *        {@link BackupTransport#TRANSPORT_ERROR} to indicate a fatal error condition that
+     *        means the platform cannot perform a backup at this time.
+     */
+    void checkFullBackupSize(long size, in ITransportStatusCallback callback);
+
+    /**
+     * 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.
+     * @param callback a callback that is completed with a {@code int} which is
+     *        one of: {@link BackupTransport#TRANSPORT_OK} on successful processing of the data,
+     *        {@link BackupTransport#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.
+     */
+    void sendBackupData(int numBytes, in ITransportStatusCallback callback);
+
+    /**
+     * Tells the transport to cancel the currently-ongoing full backup operation.
+     *
+     * @param callback a callback to indicate that transport has cancelled the operation,
+     *        does not return any value (see {@link ITransportCallback#onVoidReceived}).
+     */
+    void cancelFullBackup(in ITransportStatusCallback callback);
 
     /**
      * Ask the transport whether this app is eligible for backup.
@@ -245,9 +323,11 @@ interface IBackupTransport {
      * @param targetPackage The identity of the application.
      * @param isFullBackup If set, transport should check if app is eligible for full data backup,
      *   otherwise to check if eligible for key-value backup.
-     * @return Whether this app is eligible for backup.
+     * @param resultFuture an {@link AndroidFuture} that is completed with a {@code boolean}
+     *        indicating whether this app is eligible for backup.
      */
-    boolean isAppEligibleForBackup(in PackageInfo targetPackage, boolean isFullBackup);
+    void isAppEligibleForBackup(in PackageInfo targetPackage, boolean isFullBackup,
+            in AndroidFuture<boolean> resultFuture);
 
     /**
      * Ask the transport about current quota for backup size of the package.
@@ -255,9 +335,11 @@ interface IBackupTransport {
      * @param packageName ID of package to provide the quota.
      * @param isFullBackup If set, transport should return limit for full data backup, otherwise
      *                     for key-value backup.
-     * @return Current limit on full data backup size in bytes.
+     * @param resultFuture an {@link AndroidFuture} that is completed with a {@code long}: current
+     *        limit on full data backup size in bytes.
      */
-    long getBackupQuota(String packageName, boolean isFullBackup);
+    void getBackupQuota(String packageName, boolean isFullBackup,
+            in AndroidFuture<long> resultFuture);
 
     // full restore stuff
 
@@ -284,13 +366,14 @@ interface IBackupTransport {
      * @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 0 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.  Any negative
-     *    return value is treated as equivalent to {@link BackupTransport#TRANSPORT_ERROR},
-     *    indicating a fatal error condition that precludes further restore operations
-     *    on the current dataset.
+     * @param callback a callback that is completed with an {@code int}: 0 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.  Any negative return value is
+     *    treated as equivalent to {@link BackupTransport#TRANSPORT_ERROR}, indicating a fatal error
+     *    condition that precludes further restore operations on the current dataset.
      */
-    int getNextFullRestoreDataChunk(in ParcelFileDescriptor socket);
+    void getNextFullRestoreDataChunk(in ParcelFileDescriptor socket,
+            in ITransportStatusCallback callback);
 
     /**
      * If the OS encounters an error while processing {@link RestoreDescription#TYPE_FULL_STREAM}
@@ -300,19 +383,21 @@ interface IBackupTransport {
      * 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.
+     * @param callback a callback that is completed with {@code int}, which is
+     *    one of: {@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.
      */
-    int abortFullRestore();
+    void abortFullRestore(in ITransportStatusCallback callback);
 
     /**
-     * Returns flags with additional information about the transport, which is accessible to the
+     * @param resultFuture an {@link AndroidFuture} that is completed with an {@code int}: flags
+     * with additional information about the transport, which is accessible to the
      * {@link android.app.backup.BackupAgent}. This allows the agent to decide what to backup or
      * restore based on properties of the transport.
      *
      * <p>For supported flags see {@link android.app.backup.BackupAgent}.
      */
-    int getTransportFlags();
+    void getTransportFlags(in AndroidFuture<int> resultFuture);
 }
diff --git a/core/java/com/android/internal/backup/ITransportStatusCallback.aidl b/core/java/com/android/internal/backup/ITransportStatusCallback.aidl
new file mode 100644
index 000000000000..a731480b4c6f
--- /dev/null
+++ b/core/java/com/android/internal/backup/ITransportStatusCallback.aidl
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2021 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.internal.backup;
+
+/**
+* A callback class for {@link IBackupTransport}
+*
+* {@hide}
+*/
+oneway interface ITransportStatusCallback {
+    /**
+    * Callback for methods that complete with an {@code int} status.
+    */
+    void onOperationCompleteWithStatus(int status);
+
+    /**
+    * Callback for methods that complete without a value.
+    */
+    void onOperationComplete();
+}