code: /*
   * Copyright (c) 2003 The Visigoth Software Society. All rights
   * reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. The end-user documentation included with the redistribution, if
   *    any, must include the following acknowledgement:
   *       "This product includes software developed by the
   *        Visigoth Software Society (http://www.visigoths.org/)."
   *    Alternately, this acknowledgement may appear in the software
   *    itself, if and wherever such third-party acknowledgements
   *    normally appear.
   *
   * 4. Neither the name "FreeMarker", "Visigoth", nor any of the names
   *    of the project contributors may be used to endorse or promote
   *    products derived from this software without prior written
   *    permission. For written permission, please contact
   *    visigoths@visigoths.org.
   *
   * 5. Products derived from this software may not be called
   *    "FreeMarker" or "Visigoth" nor may "FreeMarker" or "Visigoth"
   *    appear in their names without prior written permission of the
   *    Visigoth Software Society.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED.  IN NO EVENT SHALL THE VISIGOTH SOFTWARE SOCIETY OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Visigoth Software Society. For more
   * information on the Visigoth Software Society, please see
   * http://www.visigoths.org/
   */
  
  package freemarker.eclipse.editors;
  
  import java.util.Vector;
  
  import org.eclipse.jface.text.rules.ICharacterScanner;
  import org.eclipse.jface.text.rules.IRule;
  import org.eclipse.jface.text.rules.IToken;
  import org.eclipse.jface.text.rules.MultiLineRule;
  import org.eclipse.jface.text.rules.RuleBasedScanner;
  import org.eclipse.jface.text.rules.Token;
  import org.eclipse.jface.text.rules.WhitespaceRule;
  
  /**
   * The XML tag scanner. This class handles the lexical scanning
   * of the XML tag partitions, separating out FreeMarker constructs
   * into their own tokens (with their own colors).
   *
   * @version $Id: version $
   * @author <a href="mailto:stephan@chaquotay.net">Stephan Mueller</a>
   * @author <a href="mailto:per&#64;percederberg.net">Per Cederberg</a>
   */
  @SuppressWarnings({"rawtypes", "unchecked"})
  public class XmlScanner extends RuleBasedScanner {
  
      /**
       * The stack of initiated character sequences. When a quote or a
       * FreeMarker directive is encountered, the starting character
       * sequence is added to the stack. The stack can then be used to
       * check for a matching end sequence. It is also used to ensure
       * proper nesting of attributes and directives.
       */
      private Vector stack = new Vector();
  
      /**
       * Creates a new XML tag scanner.
       *
       * @param manager        the color manager to use
       */
      public XmlScanner(ITokenManager manager) {
          Vector   rules = new Vector();
          IRule[]  result;
          IToken    comment;
          IToken    directive;
          IToken    interpolation;
          IToken    string;
  
          // Retrieve tokens
          string = manager.getStringToken();
          comment = manager.getCommentToken();
          directive = manager.getDirectiveToken();
          interpolation = manager.getInterpolationToken();
  
          // Add rules for FreeMarker constructs
          rules.add(new MultiLineRule("<#--", "-->", comment));
          rules.add(new XmlDirectiveRule(directive));
          rules.add(new InterpolationRule(interpolation));
  
          // Add rule for XML attributes
          rules.add(new XmlAttributeRule(string));
  
          // Add generic whitespace rule.
          rules.add(new WhitespaceRule(new WhitespaceDetector()));
  
          // Set scanner rules
          result = new IRule[rules.size()];
          rules.copyInto(result);
          setRules(result);
      }
  
      /**
       * Returns the top character sequence in the stack.
       *
       * @return the top character sequence in the stack, or
       *         null if the stack is empty
       */
      protected String topSequence() {
          if (stack.isEmpty()) {
              return null;
          } else {
              return (String) stack.lastElement();
          }
      }
  
      /**
       * Adds a new character sequence to the top of the stack.
       *
       * @param str            the character sequence to add
       */
      protected void pushSequence(String str) {
          stack.add(str);
      }
  
      /**
       * Removes the top character sequence from the stack.
       */
      protected void popSequence() {
          if (stack.size() > 0) {
              stack.remove(stack.size() - 1);
          }
      }
  
      /**
       * A simple XML attribute value rule. This rule is used to match
       * XML attribute values. It interrupts and resumes matching for
       * FreeMarker directives and interpolations.
       *
       * @version $Id: version $
       * @author <a href="mailto:stephan@chaquotay.net">Stephan Mueller</a>
       * @author <a href="mailto:per&#64;percederberg.net">Per Cederberg</a>
       */
      protected class XmlAttributeRule implements IRule {
  
          /**
           * The token to return for this rule.
           */
          private final IToken token;
  
          /**
           * Creates a new XML attribute rule.
           *
           * @param token          the token to use for this rule
           */
          public XmlAttributeRule(IToken token) {
              this.token = token;
          }
  
          /**
           * Checks if character is an XML quote character.
           *
           * @param c              the character to check
           *
           * @return true if the character is a quote character, or
           *         false otherwise
           */
          private boolean isQuoteChar(char c) {
              return c == '"' || c == '\'';
          }
  
          /*
           * @see org.eclipse.jface.text.rules.IRule#evaluate(org.eclipse.jface.text.rules.ICharacterScanner)
           */
          public IToken evaluate(ICharacterScanner scanner) {
              String  start;
              int     c;
  
              // Check for quote start (if not already read)
              start = topSequence();
              if (start == null || !isQuoteChar(start.charAt(0))) {
                  c = scanner.read();
                  if (c == EOF || !isQuoteChar((char) c)) {
                      scanner.unread();
                      return Token.UNDEFINED;
                  }
                  pushSequence(String.valueOf((char) c));
                  start = topSequence();
              }
  
              // Read until quote end, interpolation or (user-)directive
              do {
                  c = scanner.read();
                  if (c == '$' || c == '#') {
                      c = scanner.read();
                      scanner.unread();
                      if (c == '{') {
                          scanner.unread();
                          return token;
                      }
                      c = '$';
                  } else if (c == '<') {
                      c = scanner.read();
                      if (c == '/') {
                          c = scanner.read();
                          scanner.unread();
                      }
                      scanner.unread();
                      if (c == '#' || c == '@') {
                          scanner.unread();
                          return token;
                      }
                      c = '<';
                  }
              } while (c != EOF && c != start.charAt(0));
  
              // Remove from stack and return result
              popSequence();
              return token;
          }
      }
  
      /**
       * A simple FreeMarker directive rule. This rule is used to match
       * FreeMarker directives withing XML partitions. It interrupts
       * and resumes matching for FreeMarker comments.
       *
       * @version $Id: version $
       * @author <a href="mailto:per&#64;percederberg.net">Per Cederberg</a>
       */
      protected class XmlDirectiveRule implements IRule {
  
          /**
           * The token to return for this rule.
           */
          private final IToken token;
  
          /**
           * Creates a new XML attribute rule.
           *
           * @param token          the token to use for this rule
           */
          public XmlDirectiveRule(IToken token) {
              this.token = token;
          }
  
          /*
           * @see org.eclipse.jface.text.rules.IRule#evaluate(org.eclipse.jface.text.rules.ICharacterScanner)
           */
          public IToken evaluate(ICharacterScanner scanner) {
              String  start;
              int     parens = 0;
              int     c;
  
              // Check for directive start (if not already read)
              start = topSequence();
              if (start == null || !start.equals("<#")) {
                  if (!FreemarkerTools.readDirectiveStart(scanner)) {
                      return Token.UNDEFINED;
                  }
                  pushSequence("<#");
              }
  
              // Read until directive end or comment
              do {
                  c = scanner.read();
                  if (c == '<') {
                      scanner.unread();
                      if (FreemarkerTools.readCommentStart(scanner)) {
                          scanner.unread();
                          scanner.unread();
                          scanner.unread();
                          scanner.unread();
                          return token;
                      }
                      c = scanner.read();
                  } else if (c == '"') {
                      FreemarkerTools.readQuoteEnd(scanner);
                  } else if (c == '(') {
                      parens++;
                  } else if (c == ')') {
                      parens--;
                  }
              } while (c != EOF && (c != '>' || parens > 0));
  
              // Remove from stack and return result
              popSequence();
              return token;
          }
      }
  }
  