Hypatia/app/src/main/java/us/spotco/malwarescanner/Database.java

package us.spotco.malwarescanner;

import android.content.Context;
import android.os.AsyncTask;
import android.widget.TextView;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Scanner;

public class Database {

    private static Context context = null;
    private static TextView log = null;
    private static File databasePath = null;

    public static ArrayList<SignatureDatabase> signatureDatabases = new ArrayList<SignatureDatabase>();

    public static HashMap<String, String> signaturesMD5 = new HashMap<String, String>();
    public static HashMap<String, String> signaturesSHA1 = new HashMap<String, String>();
    public static HashMap<String, String> signaturesSHA256 = new HashMap<String, String>();

    public Database(Context context, TextView log) {
        this.context = context;
        this.log = log;
        this.databasePath = new File(context.getFilesDir() + "/signatures/");
        this.databasePath.mkdir();

        signatureDatabases.add(new SignatureDatabase("https://spotco.us/clamav-main.hdb", "clamav-main.hdb"));
        signatureDatabases.add(new SignatureDatabase("https://spotco.us/clamav-main.hsb", "clamav-main.hsb"));
        signatureDatabases.add(new SignatureDatabase("http://clamav.bofhland.org/bofhland_malware_attach.hdb", "bofhland_malware_attach.hdb"));
        signatureDatabases.add(new SignatureDatabase("http://cdn.malware.expert/malware.expert.hdb", "malware.expert.hdb"));
        signatureDatabases.add(new SignatureDatabase("http://cdn.rfxn.com/downloads/rfxn.hdb", "rfxn.hdb"));
    }

    public static boolean doesDatabaseExist() {
        return databasePath.listFiles().length > 0;
    }

    public static void updateDatabase(ArrayList<SignatureDatabase> signatureDatabases) {
        for (SignatureDatabase signatureDatabase : signatureDatabases) {
            new Downloader().execute(signatureDatabase.getUrl(), databasePath + "/" + signatureDatabase.getName());
        }
    }

    public static void loadDatabase(ArrayList<SignatureDatabase> signatureDatabases) {
        signaturesMD5 = new HashMap<String, String>();
        signaturesSHA1 = new HashMap<String, String>();
        signaturesSHA256 = new HashMap<String, String>();
        System.gc();
        for (SignatureDatabase database : signatureDatabases) {
            File databaseLocation = new File(databasePath + "/" + database.getName());
            if (databaseLocation.exists()) {
                if (database.getName().contains(".hdb")) {//.hdb format: md5, size, name
                    try {
                        Scanner scanner = new Scanner(databaseLocation);
                        while (scanner.hasNextLine()) {
                            String[] line = scanner.nextLine().split(":");
                            signaturesMD5.put(line[0], line[2]);
                        }
                        scanner.close();
                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    }
                } else if (database.getName().contains(".hsb")) {//.hsb format: sha256, size, name
                    try {
                        Scanner scanner = new Scanner(databaseLocation);
                        while (scanner.hasNextLine()) {
                            String[] line = scanner.nextLine().split(":");
                            if (line[0].length() == 32) {
                                signaturesSHA1.put(line[0], line[2]);
                            } else {
                                signaturesSHA256.put(line[0], line[2]);
                            }
                        }
                        scanner.close();
                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
        System.gc();
    }

    public static String checkInDatabase(String hash) {
        if (hash.length() == 32) {
            if (signaturesMD5.containsKey(hash)) {
                return signaturesMD5.get(hash);
            }
            if (signaturesSHA1.containsKey(hash)) {
                return signaturesSHA1.get(hash);
            }
        } else if (hash.length() == 64) {
            if (signaturesSHA256.containsKey(hash)) {
                return signaturesSHA256.get(hash);
            }
        }
        return null;
    }

    public static class Downloader extends AsyncTask<String, String, String> {

        @Override
        protected String doInBackground(String... strings) {
            String url = strings[0];
            File out = new File(strings[1]);
            try {
                HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();
                connection.setConnectTimeout(45000);
                connection.setReadTimeout(45000);
                connection.addRequestProperty("User-Agent", "Theia: Open Source Android Malware Scanner - Database Updater");
                if (out.exists()) {
                    connection.setIfModifiedSince(out.lastModified());
                }
                connection.connect();
                int res = connection.getResponseCode();
                if (res != 304) {
                    if (res == 200) {
                        if (out.exists()) {
                            out.delete();
                        }
                        FileOutputStream fileOutputStream = new FileOutputStream(out);

                        final byte data[] = new byte[1024];
                        int count;
                        while ((count = connection.getInputStream().read(data, 0, 1024)) != -1) {
                            fileOutputStream.write(data, 0, count);
                        }

                        fileOutputStream.close();
                        publishProgress("Successfully downloaded " + url + "\n");
                    } else {
                        publishProgress("File not downloaded " + res + "\n");
                    }
                } else {
                    publishProgress("File not changed " + url + "\n");
                }
                connection.disconnect();
            } catch (Exception e) {
                e.printStackTrace();
                publishProgress("Failed to download file from " + url + "\n");
            }

            return null;
        }

        @Override
        protected void onProgressUpdate(String... progress) {
            log.append(progress[0] + "\n");
        }

        @Override
        protected void onPostExecute(String result) {

        }
    }
}