CommandLineUtil.java

// Copyright (c) 2003-2008 by Leif Frenzel. All rights reserved.
// This code is made available under the terms of the Eclipse Public License,
// version 1.0 (EPL). See http://www.eclipse.org/legal/epl-v10.html
package net.sf.eclipsefp.haskell.util;

import java.util.ArrayList;
import java.util.List;


/** <p>parses command line arguments out of one big string into
  * a list.</p>
  *
  * @author Leif Frenzel
  */
public class CommandLineUtil {

  private static final char ARG_DELIMITER = ' ';
  private static final char ARG_DBL_QUOTE = '"';

  /** <p>renders the passed array into one command line string.</p> */
  public static String renderCommandLine( final String[] commandLine ) {
    StringBuilder buf = new StringBuilder(100);
    if(commandLine!=null && commandLine.length > 0 ) {
      for (String s:commandLine){
        addArg(buf,s);
      }
    }
    return buf.toString();
  }

  /** <p>renders the passed list into one command line string.</p> */
  public static String renderCommandLine( final List<String> commandLine ) {
    StringBuilder buf = new StringBuilder(100);
    if(commandLine!=null &&  commandLine.size() > 0 ) {
      for (String s:commandLine){
        addArg(buf,s);
      }
    }
    return buf.toString();
  }

  private static void addArg(final StringBuilder sb,final String arg){
    if (arg!=null && arg.trim().length()>0){
      if (sb.length()>0){
        sb.append(' ');
      }
       sb.append(quoteArg(arg));
    }
  }

  private static String quoteArg(final String arg){
    if (arg.indexOf(' ' )>-1 || arg.indexOf( '\t' )>-1  || arg.indexOf( '"' )>-1){
      if (arg.charAt( 0 )!='"' && (arg.charAt( arg.length()-1 )!='"')){
        StringBuilder sb=new StringBuilder();
        sb.append("\""); //$NON-NLS-1$
        sb.append(arg.replace( "\"", "\"\"" )); //$NON-NLS-1$ //$NON-NLS-2$
        sb.append("\""); //$NON-NLS-1$
        return sb.toString();
      }
    }

    return arg;
  }

  /** <p>parses the argument text into an array of individual arguments using
    * the space character as the delimiter.</p>
    *
    * <p>An individual argument containing spaces must have a double quote (")
    * at the start and end. Two double quotes together is taken to mean an
    * embedded double quote in the argument text.</p>
    */
  public static String[] parse( final String content ) {
    String[] result = new String[ 0 ];
    if( content != null && content.length() > 0 ) {
      List<String> alResult = new ArrayList<>();
      boolean inQuotes = false;
      int start = 0;
      int end = content.length();
      StringBuffer buffer = new StringBuffer( end );

      while( start < end ) {
        char ch = content.charAt( start );
        start++;

        switch( ch ) {
          case ARG_DELIMITER :
            if( inQuotes ) {
              buffer.append( ch );
            } else {
              if( buffer.length() > 0 ) {
                alResult.add( buffer.toString() );
                buffer.setLength( 0 );
              }
            }
            break;

          case ARG_DBL_QUOTE :
            if( start < end ) {
              if( content.charAt( start ) == ARG_DBL_QUOTE ) {
                // Two quotes together represents one quote
                buffer.append( ch );
                start++;
              } else {
                inQuotes = !inQuotes;
              }
            } else {
              // A lone quote at the end, just drop it.
              inQuotes = false;
            }
            break;

          default :
            buffer.append( ch );
            break;
        }
      }

      if( buffer.length() > 0 ) {
        alResult.add( buffer.toString() );
      }

      result = new String[ alResult.size() ];
      alResult.toArray( result );
    }
    return result;
  }
}