Utils.java

/*
 *
 *  *    Copyright (C) 2019 Amit Shekhar
 *  *    Copyright (C) 2011 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.amitshekhar.utils;

import android.content.res.AssetManager;
import android.text.TextUtils;

import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.Map;

/**
 * Created by amitshekhar on 06/02/17.
 */

public class Utils {

    private static final String TAG = "Utils";

    private Utils() {
        // This class in not publicly instantiable
    }

    public static String detectMimeType(String fileName) {
        if (TextUtils.isEmpty(fileName)) {
            return null;
        } else if (fileName.endsWith(".html")) {
            return "text/html";
        } else if (fileName.endsWith(".js")) {
            return "application/javascript";
        } else if (fileName.endsWith(".css")) {
            return "text/css";
        } else {
            return "application/octet-stream";
        }
    }

    public static byte[] loadContent(String fileName, AssetManager assetManager) throws IOException {
        InputStream input = null;
        try {
            ByteArrayOutputStream output = new ByteArrayOutputStream();
            input = assetManager.open(fileName);
            byte[] buffer = new byte[1024];
            int size;
            while (-1 != (size = input.read(buffer))) {
                output.write(buffer, 0, size);
            }
            output.flush();
            return output.toByteArray();
        } catch (FileNotFoundException e) {
            return null;
        } finally {
            try {
                if (null != input) {
                    input.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    public static byte[] getDatabase(String selectedDatabase, Map<String, File> databaseFiles) {
        if (TextUtils.isEmpty(selectedDatabase) || !databaseFiles.containsKey(selectedDatabase)) {
            return null;
        }

        byte[] byteArray = new byte[0];
        File file = databaseFiles.get(selectedDatabase);

        try (InputStream is = new FileInputStream(file);
             ByteArrayOutputStream bos = new ByteArrayOutputStream()) {
            byte[] b = new byte[(int) file.length()];
            int bytesRead;

            while ((bytesRead = is.read(b)) != -1) {
                bos.write(b, 0, bytesRead);
            }

            byteArray = bos.toByteArray();
        } catch (Exception e) {
            e.printStackTrace();
        }

        return byteArray;
    }

    public static boolean isDbEncrypted(String database, Map<String, File> databaseFiles) {
        if (TextUtils.isEmpty(database) || !databaseFiles.containsKey(database)) {
            return false;
        }
        File file = databaseFiles.get(database);
        try (DataInputStream is = new DataInputStream(new FileInputStream(file))) {
            byte[] b = new byte[16];
            is.readFully(b);
            String string = new String(b);
            return !"SQLite format 3\000".equals(string);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return false;
    }
}