[CODEC-212] Create a minimal Digest command line utility: org.apache.commons.codec.digest.Digest.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/codec/trunk@1743780 13f79535-47bb-0310-9956-ffa450edef68

Author: garydgregory

src/changes/changes.xml

@@ -47,6 +47,7 @@ The <action> type attribute can be add,update,fix,remove.
       <action dev="ggregory" type="fix" issue="CODEC-207" due-to="Gary Gregory">Charsets Javadoc breaks build when using Java 8</action>         
       <action dev="ggregory" type="fix" issue="CODEC-199" due-to="Yossi Tamari">Bug in HW rule in Soundex</action>         
       <action dev="ggregory" type="fix" issue="CODEC-209" due-to="Gary Gregory">Javadoc for SHA-224 DigestUtils methods should mention Java 1.8.0 restriction instead of 1.4.0.</action>         
+      <action dev="ggregory" type="add" issue="CODEC-212" due-to="Gary Gregory">Create a minimal Digest command line utility: org.apache.commons.codec.digest.Digest</action>         
       <action dev="ggregory" type="add" issue="CODEC-211" due-to="Gary Gregory">Create enum MessageDigestAlgorithm and deprecate class MessageDigestAlgorithms</action>         
       <action dev="ggregory" type="add" issue="CODEC-210" due-to="Gary Gregory">Add DigestUtils.getDigest(String, MessageDigest)</action>         
       <action dev="ggregory" type="add" issue="CODEC-208" due-to="Gary Gregory">Make some DigestUtils APIs public</action>         

src/main/java/org/apache/commons/codec/digest/Digest.java

@@ -0,0 +1,120 @@
+/*
+ * 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.commons.codec.digest;
+
+import java.io.File;
+import java.io.IOException;
+import java.security.MessageDigest;
+
+import org.apache.commons.codec.binary.Hex;
+
+/**
+ * A minimal command line to run digest over files.
+ *
+ * @see #main(String[])
+ */
+public class Digest {
+
+    /**
+     * Runs the digest algorithm in {@code args[0]} on the file in {@code args[1]}. If there is no {@code args[1]}, use
+     * standard input.
+     * 
+     * <p>
+     * The algorithm can also be {@code ALL} or {@code *} to output one line for each known algorithm.
+     * </p>
+     * 
+     * @param args
+     *            {@code args[0]} is one of {@link MessageDigestAlgorithm} name, {@link MessageDigest} name, {@code ALL}
+     *            , or {@code *}. {@code args[1]} is a FILE.
+     * @throws IOException
+     */
+    public static void main(String[] args) throws IOException {
+        new Digest(args).run();
+    }
+
+    private final String algorithm;
+    private final String[] args;
+    private final String source;
+
+    private Digest(final String[] args) {
+        if (args == null) {
+            throw new IllegalArgumentException("args");
+        }
+        if (args.length == 0) {
+            throw new IllegalArgumentException(
+                    String.format("Usage: java %s [algorithm] [FILE|DIRECTORY]", Digest.class.getName()));
+        }
+        this.args = args;
+        algorithm = args[0];
+        source = args.length == 1 ? null : args[1];
+    }
+
+    private void println(String prefix, final byte[] digest) {
+        final String sourceDesc = source == null ? "-" : source;
+        System.out.println(prefix + Hex.encodeHexString(digest) + " " + sourceDesc);
+    }
+
+    private void run() throws IOException {
+        if (algorithm.equalsIgnoreCase("ALL") || algorithm.equals("*")) {
+            run(MessageDigestAlgorithm.values());
+            return;
+        }
+        final MessageDigest messageDigest = DigestUtils.getDigest(algorithm, null);
+        if (messageDigest != null) {
+            run("", messageDigest);
+        } else {
+            run("", MessageDigestAlgorithm.valueOf(algorithm).getMessageDigest());
+        }
+    }
+
+    private void run(MessageDigestAlgorithm[] digestAlgorithms) throws IOException {
+        for (int i = 0; i < digestAlgorithms.length; i++) {
+            final MessageDigestAlgorithm messageDigestAlgorithm = digestAlgorithms[i];
+            if (messageDigestAlgorithm.isAvailable()) {
+                run(messageDigestAlgorithm.getAlgorithm() + " ", messageDigestAlgorithm);
+            }
+        }
+    }
+
+    private void run(String prefix, final MessageDigest messageDigest) throws IOException {
+        if (source == null) {
+            println(prefix, DigestUtils.digest(messageDigest, System.in));
+            return;
+        }
+        final File file = new File(source);
+        if (file.isFile()) {
+            println(prefix, DigestUtils.digest(messageDigest, file));
+        } else if (file.isDirectory()) {
+            run(prefix, messageDigest, file.listFiles());
+        }
+    }
+
+    private void run(String prefix, MessageDigest messageDigest, File[] files) throws IOException {
+        for (int i = 0; i < files.length; i++) {
+            println(prefix, DigestUtils.digest(messageDigest, files[i]));
+        }
+    }
+
+    private void run(String prefix, final MessageDigestAlgorithm messageDigestAlgorithm) throws IOException {
+        run(prefix, messageDigestAlgorithm.getMessageDigest());
+    }
+
+    @Override
+    public String toString() {
+        return String.format("%s[%s]", super.toString(), args);
+    }
+}