Make full backup API available to apps

New methods for full backup/restore have been added to BackupAgent
(still hidden): onFullBackup() and onRestoreFile().  The former is the
entry point for a full app backup to adb/socket/etc: the app then writes
all of its files, entire, to the output.  During restore, the latter
new callback is invoked, once for each file being restored.

The full backup/restore interface does not use the previously-defined
BackupDataInput / BackupDataOutput classes, because those classes
provide an API designed for incremental key/value data structuring.
Instead, a new FullBackupDataOutput class has been introduced, through
which we restrict apps' abilities to write data during a full backup
operation to *only* writing entire on-disk files via a new BackupAgent
method called fullBackupFile().

"FullBackupAgent" exists now solely as a concrete shell class that
can be instantiated in the case of apps that do not have their own
BackupAgent implementations.

Along with the API change, responsibility for backing up the .apk
file and OBB container has been moved into the framework rather than
have the application side of the transaction do it.

Change-Id: I12849b06b1a6e4c44d080587c1e9828a52b70dae

2 files changed, 56 insertions, 54 deletions

diff --git a/packages/SettingsProvider/AndroidManifest.xml b/packages/SettingsProvider/AndroidManifest.xml
index e5f52e2..dd0d064 100644
--- a/packages/SettingsProvider/AndroidManifest.xml
+++ b/packages/SettingsProvider/AndroidManifest.xml
@@ -6,7 +6,6 @@
                  android:label="@string/app_label"
                  android:process="system"
                  android:backupAgent="SettingsBackupAgent"
-                 android:fullBackupAgent="SettingsBackupAgent"
                  android:killAfterRestore="false"
                  android:icon="@drawable/ic_launcher_settings">
                  
diff --git a/packages/SettingsProvider/src/com/android/providers/settings/SettingsBackupAgent.java b/packages/SettingsProvider/src/com/android/providers/settings/SettingsBackupAgent.java
index 9469601..3a7a6e1 100644
--- a/packages/SettingsProvider/src/com/android/providers/settings/SettingsBackupAgent.java
+++ b/packages/SettingsProvider/src/com/android/providers/settings/SettingsBackupAgent.java
@@ -36,7 +36,7 @@ import java.util.zip.CRC32;
 import android.app.backup.BackupDataInput;
 import android.app.backup.BackupDataOutput;
 import android.app.backup.BackupAgentHelper;
-import android.app.backup.FullBackup;
+import android.app.backup.FullBackupDataOutput;
 import android.content.ContentValues;
 import android.content.Context;
 import android.database.Cursor;
@@ -132,58 +132,22 @@ public class SettingsBackupAgent extends BackupAgentHelper {
         byte[] wifiSupplicantData = getWifiSupplicant(FILE_WIFI_SUPPLICANT);
         byte[] wifiConfigData = getFileData(mWifiConfigFile);
 
-        // This same agent class is used for both full and incremental backups.  A full
-        // backup is flagged by a 'null' oldState argument.  In the case of a full backup,
-        // the output is structured as tarfile contents.
-        if (oldState != null) {
-            long[] stateChecksums = readOldChecksums(oldState);
-
-            stateChecksums[STATE_SYSTEM] =
-                writeIfChanged(stateChecksums[STATE_SYSTEM], KEY_SYSTEM, systemSettingsData, data);
-            stateChecksums[STATE_SECURE] =
-                writeIfChanged(stateChecksums[STATE_SECURE], KEY_SECURE, secureSettingsData, data);
-            stateChecksums[STATE_LOCALE] =
-                writeIfChanged(stateChecksums[STATE_LOCALE], KEY_LOCALE, locale, data);
-            stateChecksums[STATE_WIFI_SUPPLICANT] =
-                writeIfChanged(stateChecksums[STATE_WIFI_SUPPLICANT], KEY_WIFI_SUPPLICANT,
-                        wifiSupplicantData, data);
-            stateChecksums[STATE_WIFI_CONFIG] =
-                writeIfChanged(stateChecksums[STATE_WIFI_CONFIG], KEY_WIFI_CONFIG, wifiConfigData,
-                        data);
-
-            writeNewChecksums(stateChecksums, newState);
-        } else {
-            // Write the data to the staging file, then emit that as our tarfile
-            // representation of the backed-up settings.
-            String root = getFilesDir().getAbsolutePath();
-            File stage = new File(root, STAGE_FILE);
-            try {
-                FileOutputStream filestream = new FileOutputStream(stage);
-                BufferedOutputStream bufstream = new BufferedOutputStream(filestream);
-                DataOutputStream out = new DataOutputStream(bufstream);
-
-                out.writeInt(FULL_BACKUP_VERSION);
-
-                out.writeInt(systemSettingsData.length);
-                out.write(systemSettingsData);
-                out.writeInt(secureSettingsData.length);
-                out.write(secureSettingsData);
-                out.writeInt(locale.length);
-                out.write(locale);
-                out.writeInt(wifiSupplicantData.length);
-                out.write(wifiSupplicantData);
-                out.writeInt(wifiConfigData.length);
-                out.write(wifiConfigData);
-
-                out.flush();    // also flushes downstream
-
-                // now we're set to emit the tar stream
-                FullBackup.backupToTar(getPackageName(), FullBackup.DATA_TREE_TOKEN, null,
-                        root, stage.getAbsolutePath(), data);
-            } finally {
-                stage.delete();
-            }
-        }
+        long[] stateChecksums = readOldChecksums(oldState);
+
+        stateChecksums[STATE_SYSTEM] =
+            writeIfChanged(stateChecksums[STATE_SYSTEM], KEY_SYSTEM, systemSettingsData, data);
+        stateChecksums[STATE_SECURE] =
+            writeIfChanged(stateChecksums[STATE_SECURE], KEY_SECURE, secureSettingsData, data);
+        stateChecksums[STATE_LOCALE] =
+            writeIfChanged(stateChecksums[STATE_LOCALE], KEY_LOCALE, locale, data);
+        stateChecksums[STATE_WIFI_SUPPLICANT] =
+            writeIfChanged(stateChecksums[STATE_WIFI_SUPPLICANT], KEY_WIFI_SUPPLICANT,
+                    wifiSupplicantData, data);
+        stateChecksums[STATE_WIFI_CONFIG] =
+            writeIfChanged(stateChecksums[STATE_WIFI_CONFIG], KEY_WIFI_CONFIG, wifiConfigData,
+                    data);
+
+        writeNewChecksums(stateChecksums, newState);
     }
 
     @Override
@@ -221,6 +185,45 @@ public class SettingsBackupAgent extends BackupAgentHelper {
     }
 
     @Override
+    public void onFullBackup(FullBackupDataOutput data)  throws IOException {
+        byte[] systemSettingsData = getSystemSettings();
+        byte[] secureSettingsData = getSecureSettings();
+        byte[] locale = mSettingsHelper.getLocaleData();
+        byte[] wifiSupplicantData = getWifiSupplicant(FILE_WIFI_SUPPLICANT);
+        byte[] wifiConfigData = getFileData(mWifiConfigFile);
+
+        // Write the data to the staging file, then emit that as our tarfile
+        // representation of the backed-up settings.
+        String root = getFilesDir().getAbsolutePath();
+        File stage = new File(root, STAGE_FILE);
+        try {
+            FileOutputStream filestream = new FileOutputStream(stage);
+            BufferedOutputStream bufstream = new BufferedOutputStream(filestream);
+            DataOutputStream out = new DataOutputStream(bufstream);
+
+            out.writeInt(FULL_BACKUP_VERSION);
+
+            out.writeInt(systemSettingsData.length);
+            out.write(systemSettingsData);
+            out.writeInt(secureSettingsData.length);
+            out.write(secureSettingsData);
+            out.writeInt(locale.length);
+            out.write(locale);
+            out.writeInt(wifiSupplicantData.length);
+            out.write(wifiSupplicantData);
+            out.writeInt(wifiConfigData.length);
+            out.write(wifiConfigData);
+
+            out.flush();    // also flushes downstream
+
+            // now we're set to emit the tar stream
+            fullBackupFile(stage, data);
+        } finally {
+            stage.delete();
+        }
+    }
+
+    @Override
     public void onRestoreFile(ParcelFileDescriptor data, long size,
             int type, String domain, String relpath, long mode, long mtime)
             throws IOException {