- /*
- * Copyright 2003-2004 The Apache Software Foundation
- *
- * 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 org.apache.tools.ant.types.selectors.modifiedselector;
-
-
- import java.io.File;
- import java.io.FileInputStream;
- import java.io.FileOutputStream;
- 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 2003-09-13
- * @since Ant 1.6
- */
- public class DigestAlgorithm implements Algorithm {
-
-
- // ----- 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 = 8 * 1024;
-
-
- // ----- 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 doesn't need any configuration.
- * Therefore it's always valid.
- * @return <i>true</i> if all is ok, otherwise <i>false</i>.
- */
- public boolean isValid() {
- return true;
- }
-
-
- /**
- * 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;
- FileOutputStream fos = 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(0x00ff & 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();
- }
- }