Add rough-draft restore API set to IBackupTransport

* getAvailableBackups returns the list of backup sets available for restore

* getAppSet() returns the set of apps available from a given backup set

* getRestoreData() streams the full backup data for a given application
(within a given backup set) into a FD; that data will be handed to the
app's backup agent for processing.

core/java/com/android/internal/backup/AdbTransport.java

@@ -1,6 +1,7 @@
 package com.android.internal.backup;
 
 import android.content.pm.PackageInfo;
+import android.os.Bundle;
 import android.os.ParcelFileDescriptor;
 import android.os.RemoteException;
 
@@ -27,4 +28,24 @@ public class AdbTransport extends IBackupTransport.Stub {
         // TODO Auto-generated method stub
         return 0;
     }
+
+    // Restore handling
+    public Bundle getAvailableBackups() throws android.os.RemoteException {
+        // !!! TODO: real implementation
+        Bundle b = new Bundle();
+        b.putIntArray("tokens", new int[0]);
+        b.putStringArray("names", new String[0]);
+        return b;
+    }
+
+    public PackageInfo[] getAppSet(int token) throws android.os.RemoteException {
+        // !!! TODO: real implementation
+        return new PackageInfo[0];
+    }
+
+    public int getRestoreData(int token, PackageInfo packageInfo, ParcelFileDescriptor data)
+            throws android.os.RemoteException {
+        // !!! TODO: real implementation
+        return 0;
+    }
 }

core/java/com/android/internal/backup/GoogleTransport.java

@@ -1,6 +1,7 @@
 package com.android.internal.backup;
 
 import android.content.pm.PackageInfo;
+import android.os.Bundle;
 import android.os.ParcelFileDescriptor;
 import android.os.RemoteException;
 
@@ -26,4 +27,23 @@ public class GoogleTransport extends IBackupTransport.Stub {
         return 0;
     }
 
+    // Restore handling
+    public Bundle getAvailableBackups() throws android.os.RemoteException {
+        // !!! TODO: real implementation
+        Bundle b = new Bundle();
+        b.putIntArray("tokens", new int[0]);
+        b.putStringArray("names", new String[0]);
+        return b;
+    }
+
+    public PackageInfo[] getAppSet(int token) throws android.os.RemoteException {
+        // !!! TODO: real implementation
+        return new PackageInfo[0];
+    }
+
+    public int getRestoreData(int token, PackageInfo packageInfo, ParcelFileDescriptor data)
+            throws android.os.RemoteException {
+        // !!! TODO: real implementation
+        return 0;
+    }
 }

core/java/com/android/internal/backup/IBackupTransport.aidl

@@ -17,6 +17,7 @@
 package com.android.internal.backup;
 
 import android.content.pm.PackageInfo;
+import android.os.Bundle;
 import android.os.ParcelFileDescriptor;
 
 /** {@hide} */
@@ -51,8 +52,8 @@ interface IBackupTransport {
     /**
      * Send one application's data to the backup destination.
      *
-     * @param package The identity of the application whose data is being backed up.  This
+     * @param packageInfo The identity of the application whose data is being backed up.
-     *   specifically includes the signature list for the package.
+     *   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.
@@ -60,6 +61,40 @@ interface IBackupTransport {
      */
     int performBackup(in PackageInfo packageInfo, in ParcelFileDescriptor data);
 
+    /**
+     * Get the set of backups currently available over this transport.
+     *
+     * @return backups A bundle containing two elements:  an int array under the key
+     *   "tokens" whose entries are a transport-private identifier for each backup set;
+     *   and a String array under the key "names" whose entries are the user-meaningful
+     *   names corresponding to the backup sets at each index in the tokens array.
+     **/
+    Bundle getAvailableBackups();
+
+    /**
+     * Get the set of applications from a given backup image.
+     *
+     * @param token A backup token as returned by {@link availableBackups}.
+     * @return An array of PackageInfo objects describing all of the applications
+     *   available for restore from the given backup set.  This should include the list
+     *   of signatures for each package so that the Backup Manager can filter using that
+     *   information.
+     */
+    PackageInfo[] getAppSet(int token);
+
+    /**
+     * Retrieve one application's data from the backup destination.
+     *
+     * @param token The backup record from which a restore is being requested.
+     * @param packageInfo The identity of the application whose data is being restored.
+     *   This must include the signature list for the package; it is up to the transport
+     *   to verify that the requested app's signatures match the saved backup record
+     *   because the transport cannot necessarily trust the client device.
+     * @param data An open, writeable file into which the backup image should be stored.
+     * @return Zero on success; a nonzero error code on failure.
+     */
+    int getRestoreData(int token, in PackageInfo packageInfo, in ParcelFileDescriptor data);
+
     /**
      * Terminate the backup session, closing files, freeing memory, and cleaning up whatever
      * other state the transport required.