maven-scm-providers/maven-scm-providers-git/maven-scm-provider-git-commons/src/main/java/org/apache/maven/scm/provider/git/command/diff/GitDiffConsumer.java

package org.apache.maven.scm.provider.git.command.diff;

/*
 * 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.
 */

import org.apache.maven.scm.ScmFile;
import org.apache.maven.scm.ScmFileStatus;
import org.apache.maven.scm.log.ScmLogger;
import org.apache.regexp.RE;
import org.apache.regexp.RESyntaxException;
import org.codehaus.plexus.util.cli.StreamConsumer;

import java.io.File;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @author <a href="mailto:brett@apache.org">Brett Porter</a>
 * @author <a href="mailto:struberg@yahoo.de">Mark Struberg</a>
 */
public class GitDiffConsumer
    implements StreamConsumer
{
	// diff --git a/readme.txt b/readme.txt
	// index fea1611..9e131cf 100644
	// --- a/readme.txt
	// +++ b/readme.txt
	// @@ -1 +1 @@
	// -/readme.txt
	// \ No newline at end of file
	// +new version of /readme.txt


	/**
	 * patern matches the index line of the diff comparison
	 * paren.1 matches the first file
	 * paren.2 matches the 2nd file
	 */
    private final static String DIFF_FILES_PATTERN = "^diff --git\\sa/(.*)\\sb/(.*)";

    private final static String START_REVISION_TOKEN = "---";

    private final static String END_REVISION_TOKEN = "+++";

    private final static String ADDED_LINE_TOKEN = "+";

    private final static String REMOVED_LINE_TOKEN = "-";

    private final static String UNCHANGED_LINE_TOKEN = " ";

    private final static String CHANGE_SEPARATOR_TOKEN = "@@";

    private final static String NO_NEWLINE_TOKEN = "\\ No newline at end of file";

    private final static String INDEX_LINE_TOKEN = "index ";

    private final static String NEW_FILE_MODE_TOKEN = "new file mode ";
    
    private final static String DELETED_FILE_MODE_TOKEN = "deleted file mode ";
       
    private ScmLogger logger;

    private String currentFile;

    private StringBuffer currentDifference;

    private List changedFiles = new ArrayList();

    private Map differences = new HashMap();

    private StringBuffer patch = new StringBuffer();

    /**
     * @see #DIFF_FILES_PATTERN
     */
    private RE filesRegexp;

    // ----------------------------------------------------------------------
    //
    // ----------------------------------------------------------------------

    public GitDiffConsumer( ScmLogger logger, File workingDirectory )
    {
        this.logger = logger;
        try
        {
        	filesRegexp = new RE( DIFF_FILES_PATTERN );
        }
        catch ( RESyntaxException ex )
        {
            throw new RuntimeException(
                "INTERNAL ERROR: Could not create regexp to parse git log file. This shouldn't happen. Something is probably wrong with the oro installation.",
                ex );
        }        

    }

    // ----------------------------------------------------------------------
    // StreamConsumer Implementation
    // ----------------------------------------------------------------------

    public void consumeLine( String line )
    {
        if ( filesRegexp.match(line) )
        {
            // start a new file
            currentFile = filesRegexp.getParen(1);

            changedFiles.add( new ScmFile( currentFile, ScmFileStatus.MODIFIED ) );

            currentDifference = new StringBuffer();

            differences.put( currentFile, currentDifference );

            patch.append( line ).append( "\n" );

            return;
        }

        if ( currentFile == null )
        {
            logger.warn( "Unparseable line: '" + line + "'" );
            patch.append( line ).append( "\n" );
            return;
        }
        else if ( line.startsWith( INDEX_LINE_TOKEN ) )
        {
            // skip, though could parse to verify start revision and end revision
            patch.append( line ).append( "\n" );
        }
        else if ( line.startsWith( NEW_FILE_MODE_TOKEN ) || 
        		  line.startsWith( DELETED_FILE_MODE_TOKEN ))
        {
            // skip, though could parse to verify file mode
            patch.append( line ).append( "\n" );
        }
        else if ( line.startsWith( START_REVISION_TOKEN ) )
        {
            // skip, though could parse to verify filename, start revision
            patch.append( line ).append( "\n" );
        }
        else if ( line.startsWith( END_REVISION_TOKEN ) )
        {
            // skip, though could parse to verify filename, end revision
            patch.append( line ).append( "\n" );
        }
        else if ( line.startsWith( ADDED_LINE_TOKEN ) || line.startsWith( REMOVED_LINE_TOKEN ) ||
            line.startsWith( UNCHANGED_LINE_TOKEN ) || line.startsWith( CHANGE_SEPARATOR_TOKEN ) ||
            line.equals( NO_NEWLINE_TOKEN ) )
        {
            // add to buffer
            currentDifference.append( line ).append( "\n" );
            patch.append( line ).append( "\n" );
        }
        else
        {
            // TODO: handle property differences

            logger.warn( "Unparseable line: '" + line + "'" );
            patch.append( line ).append( "\n" );
            // skip to next file
            currentFile = null;
            currentDifference = null;
        }
    }

    public List getChangedFiles()
    {
        return changedFiles;
    }

    public Map getDifferences()
    {
        return differences;
    }

    public String getPatch()
    {
        return patch.toString();
    }

}