source: main/trunk/ant-tasks/src/org/greenstone/anttasks/DeleteChunkFromFile.java@ 22480

/*
 *    RegexSearchReplace.java
 *    A task to delete from a given starting nugget to a given ending nugget or the end of the file
 *
 *    Copyright (C) 2005 New Zealand Digital Library, http://www.nzdl.org
 *
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
package org.greenstone.anttasks;

import org.apache.tools.ant.*;
import org.apache.tools.ant.taskdefs.*;
import java.util.*;
import java.io.*;
import java.util.regex.*;


public class DeleteChunkFromFile extends Task {

    private File file = null;
    private Pattern startTag = null;
    private Pattern endTag = null;
    private boolean leaveTags = false;

    public static void main( String[] args ) {

        DeleteChunkFromFile dcff = new DeleteChunkFromFile();
        dcff.setFile(new File (args[0]));
        dcff.setStartTag(args[1]);
        dcff.setEndTag(args[2]);

        dcff.execute();

    }

    public void execute() {

        if ( file == null ) {
            throw new BuildException( "Error - No file specified !!" );
        }

        if ( startTag == null ) {
            throw new BuildException( "Error - No startTag specified !!" );
        }
        
        System.out.println( "File: " + file );
        System.out.println( "StartTag: " + startTag );
        System.out.println( "EndTag: " + endTag );
        System.out.println( "LeaveTags: " + leaveTags );

        int noReplaces = 0;

        //create the output stream
        BufferedWriter out = null;
        File temp = null;
        try {
            //create temp file.
            temp = File.createTempFile("dcff", ".tmp");

            //delete temp file when program exits.
            temp.deleteOnExit();

            //writer to temp file
            out = new BufferedWriter( new OutputStreamWriter(new FileOutputStream(temp), "UTF8") );

        } catch (IOException e) {
            throw new BuildException( "Error - Couldn't create or open the temp file" );
        }


        //create the input stream
        BufferedReader in = null;
        try {
            in = new BufferedReader( new InputStreamReader(new FileInputStream(file), "UTF8") );
        } catch ( Exception e ) {
            throw new BuildException( "Error - Couldn't open the specified file" );
        }

        //pass the file through, searching and replacing
        String line;
        boolean hasMoreLines = true;
        boolean lookingForStartTag = true;
        String toDefer = null;

        while ( hasMoreLines ) {

            //get the next line - either from the file of the leftovers from the last loop around
            if ( toDefer != null ) {
                line = toDefer;
                toDefer = null;
            } else {
                try {
                    line = in.readLine();
                } catch ( Exception e ) {
                    throw new BuildException( "Error - Couldn't read from the specified file" );
                }
            }

            if ( line == null ) {
                hasMoreLines = false;
            } else {

                String toWrite = null;
                boolean endLine = false;
                if ( lookingForStartTag ) {
                    Matcher m = startTag.matcher(line);
                    if ( m.find() ) {
                        lookingForStartTag = false;
                        toWrite = line.substring(0,leaveTags?m.end():m.start());
                        toDefer = line.substring(m.end());
                    } else {
                        toWrite = line;
                        endLine = true;
                    }
                } else if ( endTag != null ) {
                    Matcher m = endTag.matcher(line);
                    if ( m.find() ) {
                        lookingForStartTag = true;
                        toDefer = line.substring(leaveTags?m.start():m.end());
                    }
                }

                if ( toWrite != null ) {
                    try {
                        out.write(toWrite);
                        if ( endLine ) {
                            out.newLine();
                        }
                    } catch ( Exception e ) {
                        throw new BuildException( "Error - Couldn't write to the temp file" );
                    }
                }
            }
        }
            

        try {
            //close them both up
            in.close();
            out.close();
        } catch ( Exception e ) {
            throw new BuildException( "Error - Couldn't close a file" );
        }


        //copy the new file (temp) over the original
        InputStream i;
        OutputStream o;
        try {
            i = new FileInputStream(temp);
            o = new FileOutputStream(file);

        } catch ( Exception e ) {
            throw new BuildException( "Error - Couldn't open the temp file" );
        }

        try {
    
            // Transfer bytes from in to out
            byte[] buf = new byte[1024];
            int len;
            while ((len = i.read(buf)) > 0) {
               o.write(buf, 0, len);
            }

            //close them up
            i.close();
            o.close();
        } catch ( Exception e ) {
            throw new BuildException( "Error - Couldn't write to the specified file" );
        }

        System.out.println( "Finished" );
    }

   
    public void setFile(File file) {
        this.file = file;
    }

    public void setStartTag(String st) {
        try {
            this.startTag = Pattern.compile(st);
        } catch ( PatternSyntaxException pse ) {
            throw new BuildException( "Invalid start tag!!" );
        }
    }

    public void setEndTag(String et) {
        try {
            this.endTag = Pattern.compile(et);
        } catch ( PatternSyntaxException pse ) {
            throw new BuildException( "Invalid start tag!!" );
        }
    }

    public void setLeaveTags( boolean lt ) {
        this.leaveTags = lt;
    }


}