added optional appended salt for checksum calculation

pom.xml

@@ -1,21 +1,16 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!--
-
     checksum-maven-plugin - http://checksum-maven-plugin.nicoulaj.net
     Copyright © 2010-2017 checksum-maven-plugin contributors
-
     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.
-
 -->
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
@@ -82,6 +77,8 @@
     <maven-min-supported.version>3.0.4</maven-min-supported.version>
     <bouncycastle.version>1.59</bouncycastle.version>
     <plexus-utils.version>3.0.24</plexus-utils.version>
+    <apache-commons-io.version>1.3.2</apache-commons-io.version>
+    <apache-commons-lang.version>3.7</apache-commons-lang.version>
 
     <!-- Build settings -->
     <debug>false</debug>
@@ -126,6 +123,16 @@
         <artifactId>plexus-utils</artifactId>
         <version>${plexus-utils.version}</version>
       </dependency>
+      <dependency>
+        <groupId>org.apache.commons</groupId>
+        <artifactId>commons-io</artifactId>
+        <version>${apache-commons-io.version}</version>
+      </dependency>
+      <dependency>
+        <groupId>org.apache.commons</groupId>
+        <artifactId>commons-lang3</artifactId>
+        <version>${apache-commons-lang.version}</version>
+      </dependency>
     </dependencies>
   </dependencyManagement>
 
@@ -150,6 +157,14 @@
       <groupId>org.bouncycastle</groupId>
       <artifactId>bcprov-jdk15on</artifactId>
     </dependency>
+    <dependency>
+      <groupId>org.apache.commons</groupId>
+      <artifactId>commons-io</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>org.apache.commons</groupId>
+      <artifactId>commons-lang3</artifactId>
+    </dependency>
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>
@@ -271,11 +286,11 @@
       <plugin>
         <groupId>org.jacoco</groupId>
         <artifactId>jacoco-maven-plugin</artifactId>
-          <configuration>
-            <excludes>
-              <exclude>**/HelpMojo.class</exclude>
-            </excludes>
-          </configuration>
+        <configuration>
+          <excludes>
+            <exclude>**/HelpMojo.class</exclude>
+          </excludes>
+        </configuration>
         <executions>
           <execution>
             <id>setup-coverage-unit-tests</id>

src/main/java/net/nicoulaj/maven/plugins/checksum/digest/CRC32FileDigester.java

@@ -16,12 +16,16 @@
  */
 package net.nicoulaj.maven.plugins.checksum.digest;
 
+import java.io.ByteArrayInputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.io.InputStream;
 import java.util.zip.CRC32;
 import java.util.zip.CheckedInputStream;
+import org.apache.commons.io.IOUtils;
+import org.apache.commons.lang3.ArrayUtils;
 
 /**
  * Implementation of {@link FileDigester} for the CRC32 algorithm.
@@ -31,8 +35,8 @@
  * @since 1.0
  */
 public class CRC32FileDigester
-    extends AbstractFileDigester
-{
+    extends AbstractFileDigester {
+
     /**
      * The identifier of the algorithm supported by this implementation.
      */
@@ -41,42 +45,40 @@ public class CRC32FileDigester
     /**
      * Build a new instance of {@link CRC32FileDigester}.
      */
-    public CRC32FileDigester()
-    {
-        super( ALGORITHM );
+    public CRC32FileDigester() {
+        super(ALGORITHM);
     }
 
     /**
      * {@inheritDoc}
      */
-    public String calculate( File file )
-        throws DigesterException
-    {
+    public String calculate(File file, String salt)
+        throws DigesterException {
         CheckedInputStream cis;
-        try
-        {
-            cis = new CheckedInputStream( new FileInputStream( file ), new CRC32() );
-        }
-        catch ( FileNotFoundException e )
-        {
-            throw new DigesterException( "Unable to read " + file.getPath() + ": " + e.getMessage() );
+        try {
+            byte[] bytes = IOUtils.toByteArray(new FileInputStream(file));
+            if(!(null == salt)){
+                if(!salt.isEmpty()){
+                    bytes = ArrayUtils.addAll(bytes, salt.getBytes());
+                }
+            }
+            InputStream bais = new ByteArrayInputStream(bytes);
+            cis = new CheckedInputStream(bais, new CRC32());
+        } catch (IOException e) {
+            throw new DigesterException("Unable to read " + file.getPath() + ": " + e.getMessage());
         }
 
         byte[] buf = new byte[STREAMING_BUFFER_SIZE];
-        try
-        {
-            while ( cis.read( buf ) >= 0 )
-            {
+        try {
+            while (cis.read(buf) >= 0) {
                 continue;
             }
-        }
-        catch ( IOException e )
-        {
+        } catch (IOException e) {
             throw new DigesterException(
                 "Unable to calculate the " + getAlgorithm() + " hashcode for " + file.getPath() + ": "
-                    + e.getMessage() );
+                    + e.getMessage());
         }
 
-        return Long.toString( cis.getChecksum().getValue() );
+        return Long.toString(cis.getChecksum().getValue());
     }
 }

src/main/java/net/nicoulaj/maven/plugins/checksum/digest/CksumFileDigester.java

@@ -45,8 +45,14 @@ public CksumFileDigester()
 	}
 
 	@Override
-	public String calculate(File file) throws DigesterException
+	public String calculate(File file, String salt) throws DigesterException
 	{
+	    if(!(null == salt)){
+	        if(!salt.isEmpty()){
+                throw new DigesterException( "Adding a salt is currently not supported for algorithm Cksum!" );
+            }
+        }
+
 		int value = 0;
 		long length = 0L;
 		BufferedInputStream fis;

src/main/java/net/nicoulaj/maven/plugins/checksum/digest/FileDigester.java

@@ -52,6 +52,6 @@ public interface FileDigester
      * @return the current checksum.
      * @throws DigesterException if there was a problem computing the hashcode.
      */
-    String calculate( File file )
+    String calculate( File file, String salt )
         throws DigesterException;
 }

src/main/java/net/nicoulaj/maven/plugins/checksum/digest/MessageDigestFileDigester.java

@@ -55,7 +55,7 @@ protected MessageDigestFileDigester( String algorithm )
     /**
      * {@inheritDoc}
      */
-    public String calculate( File file )
+    public String calculate( File file, String salt )
         throws DigesterException
     {
         // Try to open the file.
@@ -84,7 +84,12 @@ public String calculate( File file )
                 messageDigest.update( buffer, 0, size );
                 size = fis.read( buffer, 0, STREAMING_BUFFER_SIZE );
             }
-
+            // Add salt at the end of file
+            if(!(null == salt)){
+                if(!salt.isEmpty()){
+                    messageDigest.update(salt.getBytes());
+                }
+            }
             result = new String( Hex.encode( messageDigest.digest() ) );
         }
         catch ( IOException e )

src/main/java/net/nicoulaj/maven/plugins/checksum/execution/AbstractExecution.java

@@ -67,6 +67,8 @@ public abstract class AbstractExecution
      */
     protected boolean failIfNoTargets = true;
 
+    protected String salt;
+
     /**
      * {@inheritDoc}
      */
@@ -248,6 +250,14 @@ public void setFailIfNoTargets(boolean failIfNoTargets) {
         this.failIfNoTargets = failIfNoTargets;
     }
 
+    public String getSalt() {
+        return salt;
+    }
+
+    public void setSalt(String salt) {
+        this.salt = salt;
+    }
+
     /**
      * {@inheritDoc}
      */

src/main/java/net/nicoulaj/maven/plugins/checksum/execution/Execution.java

@@ -178,6 +178,18 @@ public interface Execution
      */
     void setFailIfNoTargets(boolean failIfNoTargets);
 
+    /**
+     * Gets the specified checksum salt
+     * @return the Salt set before
+     */
+    String getSalt();
+
+    /**
+     * Sets a Salt to append to files during checksum creation
+     * @param salt
+     */
+    void setSalt(String salt);
+
     /**
      * Check that an execution can be run with the {@link #run()} method.
      *

src/main/java/net/nicoulaj/maven/plugins/checksum/execution/FailOnErrorExecution.java

@@ -69,7 +69,7 @@ public void run()
                 {
                     // Calculate the hash for the file/algo
                     FileDigester digester = DigesterFactory.getInstance().getFileDigester( algorithm );
-                    String hash = digester.calculate( file.getFile() );
+                    String hash = digester.calculate( file.getFile(), getSalt() );
 
                     // Write it to each target defined
                     for ( ExecutionTarget target : getTargets() )

src/main/java/net/nicoulaj/maven/plugins/checksum/execution/NeverFailExecution.java

@@ -99,7 +99,7 @@ public void run()
                 {
                     // Calculate the hash for the file/algo
                     FileDigester digester = DigesterFactory.getInstance().getFileDigester( algorithm );
-                    String hash = digester.calculate( file.getFile() );
+                    String hash = digester.calculate( file.getFile(), getSalt() );
 
                     // Write it to each target defined
                     for ( ExecutionTarget target : getTargets() )

src/main/java/net/nicoulaj/maven/plugins/checksum/mojo/AbstractChecksumMojo.java

@@ -152,6 +152,12 @@ abstract class AbstractChecksumMojo
     @Parameter( defaultValue = "" )
     protected String relativeSubPath = "";
 
+    /**
+     * Salt to append at the end of files before checksums are created
+     */
+    @Parameter(property = "salt")
+    protected String salt = "";
+
     /**
      * Constructor.
      *
@@ -179,6 +185,7 @@ public void execute()
         execution.setFailIfNoFiles(failIfNoFiles);
         execution.setFailIfNoAlgorithms(failIfNoAlgorithms);
         execution.setFailIfNoTargets(failIfNoTargets);
+        execution.setSalt(salt);
         if ( !quiet )
         {
             execution.addTarget( new MavenLogTarget( getLog() ) );

src/test/java/net/nicoulaj/maven/plugins/checksum/test/unit/Constants.java

@@ -40,4 +40,9 @@ public class Constants
      * Path of the sample files hashcodes directory.
      */
     public static final String SAMPLE_FILES_HASHCODES_PATH = RESOURCES_PATH + File.separator + "hashcodes";
+
+    /**
+     * Path of the sample files for salt checking
+     */
+    public static final String SAMPLE_FILES_SALT_PATH = RESOURCES_PATH + File.separator + "salt";
 }

src/test/java/net/nicoulaj/maven/plugins/checksum/test/unit/digest/CksumFileDigesterTest.java

@@ -34,7 +34,7 @@ public void testEmptyFileCksum() throws Exception {
         File empty_file = File.createTempFile("empty_file", null);
 
         CksumFileDigester cksumDigester=new CksumFileDigester();
-        String cksumEmpty = cksumDigester.calculate(empty_file);
+        String cksumEmpty = cksumDigester.calculate(empty_file, "");
 
         Assert.assertEquals("4294967295", cksumEmpty);
 

src/test/java/net/nicoulaj/maven/plugins/checksum/test/unit/digest/DigestersTest.java

@@ -116,7 +116,7 @@ public void testFilenameExtensionDefined()
      *
      * @throws DigesterException if there was a problem while calculating the checksum.
      * @throws IOException       if there was a problem reading the file containing the pre-calculated checksum.
-     * @see net.nicoulaj.maven.plugins.checksum.digest.FileDigester#calculate(java.io.File)
+     * @see net.nicoulaj.maven.plugins.checksum.digest.FileDigester#calculate(java.io.File, String)
      */
     @Test
     public void testCalculate()
@@ -127,7 +127,7 @@ public void testCalculate()
         {
             String referenceFile = Constants.SAMPLE_FILES_HASHCODES_PATH + File.separator + testFile.getName()
                 + digester.getFileExtension();
-            String calculatedHash = digester.calculate( testFile );
+            String calculatedHash = digester.calculate( testFile, "" );
             if (GENERATE_REFS)
                 FileUtils.fileWrite(referenceFile, calculatedHash);
             String correctHash = FileUtils.fileRead(referenceFile);
@@ -141,13 +141,29 @@ public void testCalculate()
      * Check an exception is thrown when attempting to calculate the checksum of a file that does not exist.
      *
      * @throws DigesterException should always happen.
-     * @see net.nicoulaj.maven.plugins.checksum.digest.FileDigester#calculate(java.io.File)
+     * @see net.nicoulaj.maven.plugins.checksum.digest.FileDigester#calculate(java.io.File, String)
      */
     @Test
     public void testCalculateExceptionThrownOnFileNotFound()
         throws DigesterException
     {
         exception.expect( DigesterException.class );
-        digester.calculate( new File( "some/path/that/does/not/exist" ) );
+        digester.calculate( new File( "some/path/that/does/not/exist" ), "" );
+    }
+
+    /**
+     * Tests the patched salt functionality
+     */
+    @Test
+    public void testWithSalt() throws IOException, NoSuchAlgorithmException, DigesterException {
+
+        File testFile = new File(Constants.SAMPLE_FILES_SALT_PATH + File.separator + "salt-target.txt");
+        String referenceHash = FileUtils.fileRead(Constants.SAMPLE_FILES_SALT_PATH + File.separator + "salt-target.txt.sha256");
+        DigesterFactory factory = DigesterFactory.getInstance();
+        FileDigester sha256 = factory.getFileDigester("sha256");
+        String calculatedHashWithSalt = sha256.calculate(testFile, "KITTYCAT");
+        String calculatedHashWithWrongSalt = sha256.calculate(testFile, "KITTYCATS");
+        Assert.assertEquals(calculatedHashWithSalt, referenceHash);
+        Assert.assertNotEquals(calculatedHashWithWrongSalt, referenceHash);
     }
 }

src/test/resources/salt/salt-target.txt

@@ -0,0 +1 @@
+This is sample file for calculation with the salt KITTYCAT.

src/test/resources/salt/salt-target.txt.sha256

@@ -0,0 +1 @@
+ae30210ed29a0192980efea77894ca8dc1c5a975f07a4844f869ede0463bf029