/*
 * Copyright (C) 2009 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.backup;

import android.content.Context;
import android.os.ParcelFileDescriptor;
import android.util.Log;

import java.io.FileDescriptor;

/** @hide */
public class FileBackupHelper {
    private static final String TAG = "FileBackupHelper";

    /**
     * Based on oldState, determine which of the files from the application's data directory
     * need to be backed up, write them to the data stream, and fill in newState with the
     * state as it exists now.
     */
    public static void performBackup(Context context,
            ParcelFileDescriptor oldState, BackupDataOutput data,
            ParcelFileDescriptor newState, String[] files) {
        String basePath = context.getFilesDir().getAbsolutePath();
        performBackup_checked(basePath, oldState, data, newState, files);
    }

    /**
     * Check the parameters so the native code doens't have to throw all the exceptions
     * since it's easier to do that from java.
     */
    static void performBackup_checked(String basePath,
            ParcelFileDescriptor oldState, BackupDataOutput data,
            ParcelFileDescriptor newState, String[] files) {
        if (files.length == 0) {
            return;
        }
        if (basePath == null) {
            throw new NullPointerException();
        }
        // oldStateFd can be null
        FileDescriptor oldStateFd = oldState != null ? oldState.getFileDescriptor() : null;
        FileDescriptor newStateFd = newState.getFileDescriptor();
        if (newStateFd == null) {
            throw new NullPointerException();
        }

        int err = performBackup_native(basePath, oldStateFd, data.mBackupWriter, newStateFd, files);

        if (err != 0) {
            throw new RuntimeException("Backup failed"); // TODO: more here
        }
    }

    native private static int performBackup_native(String basePath, FileDescriptor oldState,
            int data, FileDescriptor newState, String[] files);
}