001/*
002 * SonarQube, open source software quality management tool.
003 * Copyright (C) 2008-2014 SonarSource
004 * mailto:contact AT sonarsource DOT com
005 *
006 * SonarQube is free software; you can redistribute it and/or
007 * modify it under the terms of the GNU Lesser General Public
008 * License as published by the Free Software Foundation; either
009 * version 3 of the License, or (at your option) any later version.
010 *
011 * SonarQube is distributed in the hope that it will be useful,
012 * but WITHOUT ANY WARRANTY; without even the implied warranty of
013 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014 * Lesser General Public License for more details.
015 *
016 * You should have received a copy of the GNU Lesser General Public License
017 * along with this program; if not, write to the Free Software Foundation,
018 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
019 */
020package org.sonar.home.cache;
021
022import org.apache.commons.io.IOUtils;
023
024import java.io.File;
025import java.io.FileInputStream;
026import java.io.IOException;
027import java.io.InputStream;
028import java.math.BigInteger;
029import java.security.MessageDigest;
030
031/**
032 * Hashes used to store files in the cache directory.
033 *
034 * @since 3.5
035 */
036public class FileHashes {
037
038  private static final int STREAM_BUFFER_LENGTH = 1024;
039
040  public String of(File file) {
041    try {
042      return of(new FileInputStream(file));
043    } catch (IOException e) {
044      throw new IllegalStateException("Fail to compute hash of: " + file.getAbsolutePath(), e);
045    }
046  }
047
048  /**
049   * Computes the hash of given stream. The stream is closed by this method.
050   */
051  public String of(InputStream input) {
052    try {
053      MessageDigest digest = MessageDigest.getInstance("MD5");
054      byte[] hash = digest(input, digest);
055      return toHex(hash);
056
057    } catch (Exception e) {
058      throw new IllegalStateException("Fail to compute hash", e);
059
060    } finally {
061      IOUtils.closeQuietly(input);
062    }
063  }
064
065  private byte[] digest(InputStream input, MessageDigest digest) throws IOException {
066    final byte[] buffer = new byte[STREAM_BUFFER_LENGTH];
067    int read = input.read(buffer, 0, STREAM_BUFFER_LENGTH);
068    while (read > -1) {
069      digest.update(buffer, 0, read);
070      read = input.read(buffer, 0, STREAM_BUFFER_LENGTH);
071    }
072    return digest.digest();
073  }
074
075  static String toHex(byte[] bytes) {
076    BigInteger bi = new BigInteger(1, bytes);
077    return String.format("%0" + (bytes.length << 1) + "x", bi);
078  }
079}