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Diffstat (limited to 'framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/types/selectors/modifiedselector/DigestAlgorithm.java')
| -rw-r--r-- | framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/types/selectors/modifiedselector/DigestAlgorithm.java | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/types/selectors/modifiedselector/DigestAlgorithm.java b/framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/types/selectors/modifiedselector/DigestAlgorithm.java new file mode 100644 index 00000000..085b4fe7 --- /dev/null +++ b/framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/types/selectors/modifiedselector/DigestAlgorithm.java @@ -0,0 +1,208 @@ +/* + * 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 java.util.Locale; + +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 != null + ? algorithm.toUpperCase(Locale.ENGLISH) : null; + } + + + /** + * 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".equals(algorithm) || "MD5".equals(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() { + StringBuilder buf = new StringBuilder(); + buf.append("<DigestAlgorithm:"); + buf.append("algorithm=").append(algorithm); + buf.append(";provider=").append(provider); + buf.append(">"); + return buf.toString(); + } +} |