maven-scm-providers/maven-scm-provider-svn/src/main/java/org/apache/maven/scm/provider/svn/command/changelog/SvnChangeLogConsumer.java

package org.apache.maven.scm.provider.svn.command.changelog;

/*
 * Copyright 2003-2005 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.
 */

import org.apache.maven.scm.ChangeSet;
import org.apache.maven.scm.ChangeFile;
import org.apache.regexp.RE;
import org.apache.regexp.RESyntaxException;
import org.codehaus.plexus.util.cli.StreamConsumer;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

/**
 * @author <a href="mailto:evenisse@apache.org">Emmanuel Venisse</a>
 * @version $Id$
 */
public class SvnChangeLogConsumer
    implements StreamConsumer
{
    /** Date formatter for svn timestamp (after a little massaging) */
    private static final SimpleDateFormat SVN_TIMESTAMP = new SimpleDateFormat( "yyyy-MM-dd HH:mm:ss zzzzzzzzz" );

    /** State machine constant: expecting header */
    private static final int GET_HEADER = 1;

    /** State machine constant: expecting file information */
    private static final int GET_FILE = 2;

    /** State machine constant: expecting comments */
    private static final int GET_COMMENT = 3;

    /** A file line begins with a space character */
    private static final String FILE_BEGIN_TOKEN = " ";

    /** The file section ends with a blank line */
    private static final String FILE_END_TOKEN = "";

    /** The filename starts after 5 characters */
    private static final int FILE_START_INDEX = 5;

    /** The comment section ends with a dashed line */
    private static final String COMMENT_END_TOKEN = "------------------------------------"
                                                    + "------------------------------------";

    /** The pattern used to match svn header lines */
    private static final String pattern = "^rev (\\d+):\\s+" + // revision number
                                          "(\\w+)\\s+\\|\\s+" + // author username
                                          "(\\d+-\\d+-\\d+ " + // date 2002-08-24
                                          "\\d+:\\d+:\\d+) " + // time 16:01:00
                                          "([\\-+])(\\d\\d)(\\d\\d)"; // gmt offset -0400

    private static final String pattern2 = "^r(\\d+)\\s+\\|\\s+" +          // revision number
                                          "(\\(\\S+\\s+\\S+\\)|\\S+)\\s+\\|\\s+" + // author username
                                          "(\\d+-\\d+-\\d+ " +             // date 2002-08-24
                                          "\\d+:\\d+:\\d+) " +             // time 16:01:00
                                          "([\\-+])(\\d\\d)(\\d\\d)";      // gmt offset -0400 

    /** Current status of the parser */
    private int status = GET_HEADER;

    /** List of change log entries */
    private List entries = new ArrayList();

    /** The current log entry being processed by the parser */
    private ChangeSet currentChange;

    /** The current revision of the entry being processed by the parser */
    private String currentRevision;

    /** The current comment of the entry being processed by the parser */
    private StringBuffer currentComment;

    /** The regular expression used to match header lines */
    private RE headerRegexp;

    private RE headerRegexp2;

    /**
     * Default constructor.
     */
    public SvnChangeLogConsumer()
    {
        try
        {
            headerRegexp = new RE( pattern );
            headerRegexp2 = new RE( pattern2 );
        }
        catch ( RESyntaxException ex )
        {
            throw new RuntimeException(
                                        "INTERNAL ERROR: Could not create regexp to parse svn log file. This shouldn't happen. Something is probably wrong with the oro installation.",
                                        ex );
        }
    }

    public List getModifications()
    {
        return entries;
    }

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

    public void consumeLine( String line )
    {
        switch ( status )
        {
            case GET_HEADER:
                processGetHeader( line );
                break;
            case GET_FILE:
                processGetFile( line );
                break;
            case GET_COMMENT:
                processGetComment( line );
                break;
            default:
                throw new IllegalStateException( "Unknown state: " + status );
        }
    }

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

    /**
     * Process the current input line in the GET_HEADER state.  The
     * author, date, and the revision of the entry are gathered.  Note,
     * Subversion does not have per-file revisions, instead, the entire
     * repository is given a single revision number, which is used for
     * the revision number of each file.
     *
     * @param line A line of text from the svn log output
     */
    private void processGetHeader( String line )
    {
        if ( !headerRegexp.match( line ) )
        {
            if ( !headerRegexp2.match( line ) )
            {
                return;
            }
            else
            {
                headerRegexp = headerRegexp2;
            }
        }

        currentRevision = headerRegexp.getParen( 1 );

        currentChange = new ChangeSet();

        currentChange.setAuthor( headerRegexp.getParen( 2 ) );

        currentChange.setDate( parseDate() );

        status = GET_FILE;
    }

    /**
     * Process the current input line in the GET_FILE state.  This state
     * adds each file entry line to the current change log entry.  Note,
     * the revision number for the entire entry is used for the revision
     * number of each file.
     *
     * @param line A line of text from the svn log output
     */
    private void processGetFile( String line )
    {
        if ( line.startsWith( FILE_BEGIN_TOKEN ) )
        {
            // Skip the status flags and just get the name of the file
            String name = line.substring( FILE_START_INDEX );
            currentChange.addFile( new ChangeFile( name, currentRevision ) );

            status = GET_FILE;
        }
        else if ( line.equals( FILE_END_TOKEN ) )
        {
            // Create a buffer for the collection of the comment now
            // that we are leaving the GET_FILE state.
            currentComment = new StringBuffer();

            status = GET_COMMENT;
        }
    }

    /**
     * Process the current input line in the GET_COMMENT state.  This
     * state gathers all of the comments that are part of a log entry.
     *
     * @param line a line of text from the svn log output
     */
    private void processGetComment( String line )
    {
        if ( line.equals( COMMENT_END_TOKEN ) )
        {
            currentChange.setComment( currentComment.toString() );

            entries.add( currentChange );

            status = GET_HEADER;
        }
        else
        {
            currentComment.append( line ).append( '\n' );
        }
    }

    /**
     * Converts the date timestamp from the svn output into a date
     * object.
     *
     * @return A date representing the timestamp of the log entry.
     */
    private Date parseDate()
    {
        try
        {
            StringBuffer date = new StringBuffer().append( headerRegexp.getParen( 3 ) ).append( " GMT" )
                .append( headerRegexp.getParen( 4 ) ).append( headerRegexp.getParen( 5 ) ).append( ':' )
                .append( headerRegexp.getParen( 6 ) );

            return SVN_TIMESTAMP.parse( date.toString() );
        }
        catch ( ParseException e )
        {
            return null;
        }
    }
}