| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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 org.apache.tools.ant.types.selectors.modifiedselector; |
| |
| |
| import java.io.File; |
| import java.io.FileInputStream; |
| import java.security.DigestInputStream; |
| import java.security.MessageDigest; |
| import java.security.NoSuchAlgorithmException; |
| import java.security.NoSuchProviderException; |
| import org.apache.tools.ant.BuildException; |
| |
| |
| /** |
| * Computes a 'hashvalue' for the content of file using |
| * java.security.MessageDigest. |
| * Use of this algorithm doesn't require any additional nested <param>s. |
| * Supported <param>s are: |
| * <table> |
| * <tr> |
| * <th>name</th><th>values</th><th>description</th><th>required</th> |
| * </tr> |
| * <tr> |
| * <td> algorithm.algorithm </td> |
| * <td> MD5 | SHA (default provider) </td> |
| * <td> name of the algorithm the provider should use </td> |
| * <td> no, defaults to MD5 </td> |
| * </tr> |
| * <tr> |
| * <td> algorithm.provider </td> |
| * <td> </td> |
| * <td> name of the provider to use </td> |
| * <td> no, defaults to <i>null</i> </td> |
| * </tr> |
| * </table> |
| * |
| * @version 2004-07-08 |
| * @since Ant 1.6 |
| */ |
| public class DigestAlgorithm implements Algorithm { |
| |
| private static final int BYTE_MASK = 0xFF; |
| private static final int BUFFER_SIZE = 8192; |
| |
| // ----- member variables ----- |
| |
| |
| /** |
| * MessageDigest algorithm to be used. |
| */ |
| private String algorithm = "MD5"; |
| |
| /** |
| * MessageDigest Algorithm provider |
| */ |
| private String provider = null; |
| |
| /** |
| * Message Digest instance |
| */ |
| private MessageDigest messageDigest = null; |
| |
| /** |
| * Size of the read buffer to use. |
| */ |
| private int readBufferSize = BUFFER_SIZE; |
| |
| |
| // ----- Algorithm-Configuration ----- |
| |
| |
| /** |
| * Specifies the algorithm to be used to compute the checksum. |
| * Defaults to "MD5". Other popular algorithms like "SHA" may be used as well. |
| * @param algorithm the digest algorithm to use |
| */ |
| public void setAlgorithm(String algorithm) { |
| this.algorithm = algorithm; |
| } |
| |
| |
| /** |
| * Sets the MessageDigest algorithm provider to be used |
| * to calculate the checksum. |
| * @param provider provider to use |
| */ |
| public void setProvider(String provider) { |
| this.provider = provider; |
| } |
| |
| |
| /** Initialize the security message digest. */ |
| public void initMessageDigest() { |
| if (messageDigest != null) { |
| return; |
| } |
| |
| if ((provider != null) && !"".equals(provider) && !"null".equals(provider)) { |
| try { |
| messageDigest = MessageDigest.getInstance(algorithm, provider); |
| } catch (NoSuchAlgorithmException noalgo) { |
| throw new BuildException(noalgo); |
| } catch (NoSuchProviderException noprovider) { |
| throw new BuildException(noprovider); |
| } |
| } else { |
| try { |
| messageDigest = MessageDigest.getInstance(algorithm); |
| } catch (NoSuchAlgorithmException noalgo) { |
| throw new BuildException(noalgo); |
| } |
| } |
| } |
| |
| |
| // ----- Logic ----- |
| |
| |
| /** |
| * This algorithm supports only MD5 and SHA. |
| * @return <i>true</i> if all is ok, otherwise <i>false</i>. |
| */ |
| public boolean isValid() { |
| return "SHA".equalsIgnoreCase(algorithm) || "MD5".equalsIgnoreCase(algorithm); |
| } |
| |
| |
| /** |
| * Computes a value for a file content with the specified digest algorithm. |
| * @param file File object for which the value should be evaluated. |
| * @return The value for that file |
| */ |
| // implementation adapted from ...taskdefs.Checksum, thanks to Magesh for hint |
| public String getValue(File file) { |
| initMessageDigest(); |
| String checksum = null; |
| try { |
| if (!file.canRead()) { |
| return null; |
| } |
| FileInputStream fis = null; |
| |
| byte[] buf = new byte[readBufferSize]; |
| try { |
| messageDigest.reset(); |
| fis = new FileInputStream(file); |
| DigestInputStream dis = new DigestInputStream(fis, |
| messageDigest); |
| while (dis.read(buf, 0, readBufferSize) != -1) { |
| // do nothing |
| } |
| dis.close(); |
| fis.close(); |
| fis = null; |
| byte[] fileDigest = messageDigest.digest(); |
| StringBuffer checksumSb = new StringBuffer(); |
| for (int i = 0; i < fileDigest.length; i++) { |
| String hexStr |
| = Integer.toHexString(BYTE_MASK & fileDigest[i]); |
| if (hexStr.length() < 2) { |
| checksumSb.append("0"); |
| } |
| checksumSb.append(hexStr); |
| } |
| checksum = checksumSb.toString(); |
| } catch (Exception e) { |
| return null; |
| } |
| } catch (Exception e) { |
| return null; |
| } |
| return checksum; |
| } |
| |
| |
| /** |
| * Override Object.toString(). |
| * @return some information about this algorithm. |
| */ |
| public String toString() { |
| StringBuffer buf = new StringBuffer(); |
| buf.append("<DigestAlgorithm:"); |
| buf.append("algorithm=").append(algorithm); |
| buf.append(";provider=").append(provider); |
| buf.append(">"); |
| return buf.toString(); |
| } |
| } |