Java tutorial
/* * Copyright (C) 2012 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.providers.contacts.debug; import com.android.providers.contacts.util.Hex; import com.google.common.io.Closeables; import android.content.Context; import android.net.Uri; import android.util.Log; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.security.SecureRandom; import java.util.zip.Deflater; import java.util.zip.ZipEntry; import java.util.zip.ZipOutputStream; /** * Compress all files under the app data dir into a single zip file. * * Make sure not to output dump filenames anywhere, including logcat. */ public class DataExporter { private static String TAG = "DataExporter"; public static final String ZIP_MIME_TYPE = "application/zip"; public static final String DUMP_FILE_DIRECTORY_NAME = "dumpedfiles"; public static final String OUT_FILE_SUFFIX = "-contacts-db.zip"; /** * Compress all files under the app data dir into a single zip file, and return the content:// * URI to the file, which can be read via {@link DumpFileProvider}. */ public static Uri exportData(Context context) throws IOException { final String fileName = generateRandomName() + OUT_FILE_SUFFIX; final File outFile = getOutputFile(context, fileName); // Remove all existing ones. removeDumpFiles(context); Log.i(TAG, "Dump started..."); ensureOutputDirectory(context); final ZipOutputStream os = new ZipOutputStream(new FileOutputStream(outFile)); os.setLevel(Deflater.BEST_COMPRESSION); try { addDirectory(context, os, context.getFilesDir().getParentFile(), "contacts-files"); } finally { Closeables.closeQuietly(os); } Log.i(TAG, "Dump finished."); return DumpFileProvider.AUTHORITY_URI.buildUpon().appendPath(fileName).build(); } /** @return long random string for a file name */ private static String generateRandomName() { final SecureRandom rng = new SecureRandom(); final byte[] random = new byte[256 / 8]; rng.nextBytes(random); return Hex.encodeHex(random, true); } private static File getOutputDirectory(Context context) { return new File(context.getCacheDir(), DUMP_FILE_DIRECTORY_NAME); } private static void ensureOutputDirectory(Context context) { final File directory = getOutputDirectory(context); if (!directory.exists()) { directory.mkdir(); } } public static File getOutputFile(Context context, String fileName) { return new File(getOutputDirectory(context), fileName); } public static boolean dumpFileExists(Context context) { return getOutputDirectory(context).exists(); } public static void removeDumpFiles(Context context) { removeFileOrDirectory(getOutputDirectory(context)); } private static void removeFileOrDirectory(File file) { if (!file.exists()) return; if (file.isFile()) { Log.i(TAG, "Removing " + file); file.delete(); return; } if (file.isDirectory()) { for (File child : file.listFiles()) { removeFileOrDirectory(child); } Log.i(TAG, "Removing " + file); file.delete(); } } /** * Add all files under {@code current} to {@code os} zip stream */ private static void addDirectory(Context context, ZipOutputStream os, File current, String storedPath) throws IOException { for (File child : current.listFiles()) { final String childStoredPath = storedPath + "/" + child.getName(); if (child.isDirectory()) { // Don't need the cache directory, which also contains the dump files. if (child.equals(context.getCacheDir())) { continue; } // This check is redundant as the output directory should be in the cache dir, // but just in case... if (child.getName().equals(DUMP_FILE_DIRECTORY_NAME)) { continue; } addDirectory(context, os, child, childStoredPath); } else if (child.isFile()) { addFile(os, child, childStoredPath); } else { // Shouldn't happen; skip. } } } /** * Add a single file {@code current} to {@code os} zip stream using the file name * {@code storedPath}. */ private static void addFile(ZipOutputStream os, File current, String storedPath) throws IOException { Log.i(TAG, "Adding " + current.getAbsolutePath() + " ..."); final InputStream is = new FileInputStream(current); os.putNextEntry(new ZipEntry(storedPath)); final byte[] buf = new byte[32 * 1024]; int totalLen = 0; while (true) { int len = is.read(buf); if (len <= 0) { break; } os.write(buf, 0, len); totalLen += len; } os.closeEntry(); Log.i(TAG, "Added " + current.getAbsolutePath() + " as " + storedPath + " (" + totalLen + " bytes)"); } }