/* * HtmlScrubber.java -- cleans up HTML document tree.   * Copyright (C) 1999 Quiotix Corporation.   * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License, version 2, as  * published by the Free Software Foundation.   * * 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 (http://www.gnu.org/copyleft/gpl.txt) * for more details. */package com.quiotix.html.parser;import java.io.*;import java.util.*;/**  * HtmlScrubber is a Visitor which walks an HtmlDocument and cleans it up. * It can change tags and tag attributes to uppercase or lowercase, strip * out unnecessary quotes from attribute values, and strip trailing spaces * before a newline. * * @author Brian Goetz, Quiotix * Additional contributions by: Thorsten Weber */public class HtmlScrubber extends HtmlVisitor {  public static final int TAGS_UPCASE     = 1;  public static final int TAGS_DOWNCASE   = 2;  public static final int ATTR_UPCASE     = 4;  public static final int ATTR_DOWNCASE   = 8;  public static final int STRIP_QUOTES    = 16;  public static final int TRIM_SPACES     = 32;  public static final int DEFAULT_OPTIONS =     TAGS_DOWNCASE | ATTR_DOWNCASE | STRIP_QUOTES;  protected int flags;  protected HtmlDocument.HtmlElement previousElement;  protected boolean inPreBlock;  /** Create an HtmlScrubber with the default options (downcase tags and   * tag attributes, strip out unnecessary quotes.)    */  public HtmlScrubber() {    this(DEFAULT_OPTIONS);  };  /** Create an HtmlScrubber with the desired set of options.   * @param flags A bitmask representing the desired scrubbing options   */  public HtmlScrubber(int flags) {    this.flags = flags;  };  private static boolean safeToUnquote(String qs) {    int l, upperCount=0, lowerCount=0, idCount=0;            for (int i=1; i < qs.length()-1; i++) {      char c = qs.charAt(i);      if (Character.isUnicodeIdentifierPart(c))        ++idCount;      if (Character.isUpperCase(c))        ++upperCount;      else if (Character.isLowerCase(c))        ++lowerCount;    };    return (qs.length()-2 > 0            && (qs.length()-2 == idCount                 && (upperCount == 0 || lowerCount == 0)));  };  public void start() {    previousElement = null;    inPreBlock = false;  };  public void visit(HtmlDocument.Tag t) {    if ((flags & TAGS_UPCASE) != 0)       t.tagName = t.tagName.toUpperCase();    else if ((flags & TAGS_DOWNCASE) != 0)       t.tagName = t.tagName.toLowerCase();    for (Enumeration ae=t.attributeList.attributes.elements();         ae.hasMoreElements(); ) {      HtmlDocument.Attribute a = (HtmlDocument.Attribute) ae.nextElement();       if ((flags & ATTR_UPCASE) != 0)         a.name = a.name.toUpperCase();      else if ((flags & ATTR_DOWNCASE) != 0)         a.name = a.name.toLowerCase();      if (((flags & STRIP_QUOTES) != 0)           && a.hasValue          && ((a.value.charAt(0) == '\''                && a.value.charAt(a.value.length()-1) == '\'')              || (a.value.charAt(0) == '\"'                   && a.value.charAt(a.value.length()-1) == '\"'))          && safeToUnquote(a.value)) {        a.value = a.value.substring(1, a.value.length()-1);      };    };    previousElement = t;  }  public void visit(HtmlDocument.EndTag t) {    if ((flags & TAGS_UPCASE) != 0)       t.tagName = t.tagName.toUpperCase();    else if ((flags & TAGS_DOWNCASE) != 0)       t.tagName = t.tagName.toLowerCase();    previousElement = t;  }  public void visit(HtmlDocument.Text t)        {     if (((flags & TRIM_SPACES) != 0)         && !inPreBlock        && (previousElement instanceof HtmlDocument.Newline            || previousElement instanceof HtmlDocument.Tag            || previousElement instanceof HtmlDocument.EndTag            || previousElement instanceof HtmlDocument.Comment)) {      int i;       for (i=0; i<t.text.length(); i++)         if (t.text.charAt(i) != ' '             && t.text.charAt(i) != '\t')          break;      if (i > 0)         t.text = t.text.substring(i);    };    previousElement = t;   }  public void visit(HtmlDocument.Comment c)     { previousElement = c; }  public void visit(HtmlDocument.Newline n)     { previousElement = n; }  public void visit(HtmlDocument.Annotation a)  { previousElement = a; }  public void visit(HtmlDocument.TagBlock bl) {    if (bl.startTag.tagName.equalsIgnoreCase("PRE")        || bl.startTag.tagName.equalsIgnoreCase("SCRIPT")        || bl.startTag.tagName.equalsIgnoreCase("STYLE")) {      inPreBlock = true;      super.visit(bl);      inPreBlock = false;    }    else      super.visit(bl);  }}