HtmlFormat.cs :  » Bloggers » BlogEngine.NET » CodeFormatter » C# / CSharp Open Source

#region Copyright  2001-2003 Jean-Claude Manoli [jc@manoli.net]
/*
 * This software is provided 'as-is', without any express or implied warranty.
 * In no event will the author(s) be held liable for any damages arising from
 * the use of this software.
 * 
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 * 
 *   1. The origin of this software must not be misrepresented; you must not
 *      claim that you wrote the original software. If you use this software
 *      in a product, an acknowledgment in the product documentation would be
 *      appreciated but is not required.
 * 
 *   2. Altered source versions must be plainly marked as such, and must not
 *      be misrepresented as being the original software.
 * 
 *   3. This notice may not be removed or altered from any source distribution.
 */ 
#endregion

using System;
using System.IO;
using System.Text;
using System.Text.RegularExpressions;

namespace CodeFormatter{
  /// <summary>
  /// Generates color-coded HTML 4.01 from HTML/XML/ASPX source code.
  /// </summary>
  /// <remarks>
  /// <para>
  /// This implementation assumes that code inside &lt;script&gt; blocks 
  /// is JavaScript, and code inside &lt;% %&gt; blocks is C#.</para>
  /// <para>
  /// The default tab width is set to 2 characters in this class.</para>
  /// </remarks>
  public class HtmlFormat : SourceFormat
  {
    private CSharpFormat csf; //to format embedded C# code
    private JavaScriptFormat jsf; //to format client-side JavaScript code
    private Regex attribRegex;

    /// <summary/>
    public HtmlFormat()
    {
      const string regJavaScript = @"(?<=&lt;script(?:\s.*?)?&gt;).+?(?=&lt;/script&gt;)";
      const string regComment = @"&lt;!--.*?--&gt;";
      const string regAspTag = @"&lt;%@.*?%&gt;|&lt;%|%&gt;";
      const string regAspCode = @"(?<=&lt;%).*?(?=%&gt;)";
      const string regTagDelimiter = @"(?:&lt;/?!?\??(?!%)|(?<!%)/?&gt;)+";
      const string regTagName = @"(?<=&lt;/?!?\??(?!%))[\w\.:-]+(?=.*&gt;)";
      const string regAttributes = @"(?<=&lt;(?!%)/?!?\??[\w:-]+).*?(?=(?<!%)/?&gt;)";
      const string regEntity = @"&amp;\w+;";
      const string regAttributeMatch = @"(=?"".*?""|=?'.*?')|([\w:-]+)";
      
      //the regex object will handle all the replacements in one pass
      string regAll = "(" + regJavaScript + ")|(" + regComment + ")|(" 
        + regAspTag + ")|(" + regAspCode + ")|(" 
        + regTagDelimiter + ")|(" + regTagName + ")|("
        + regAttributes + ")|(" + regEntity + ")";

      CodeRegex = new Regex(regAll, RegexOptions.IgnoreCase | RegexOptions.Singleline);
      attribRegex = new Regex(regAttributeMatch, RegexOptions.Singleline);

      csf = new CSharpFormat();
      jsf = new JavaScriptFormat();
    }

    /// <summary>
    /// Called to evaluate the HTML fragment corresponding to each 
    /// attribute's name/value in the code.
    /// </summary>
    /// <param name="match">The <see cref="Match"/> resulting from a 
    /// single regular expression match.</param>
    /// <returns>A string containing the HTML code fragment.</returns>
    private string AttributeMatchEval(Match match)
    {
      if(match.Groups[1].Success) //attribute value
        return "<span class=\"kwrd\">" + match.ToString() + "</span>";

      if(match.Groups[2].Success) //attribute name
        return "<span class=\"attr\">" + match.ToString() + "</span>";

      return match.ToString();
    }

    /// <summary>
    /// Called to evaluate the HTML fragment corresponding to each 
    /// matching token in the code.
    /// </summary>
    /// <param name="match">The <see cref="Match"/> resulting from a 
    /// single regular expression match.</param>
    /// <returns>A string containing the HTML code fragment.</returns>
    protected override string MatchEval(Match match)
    {
      if(match.Groups[1].Success) //JavaScript code
      {
        string s = match.ToString();
        return jsf.FormatSubCode(match.ToString());
      }
      if(match.Groups[2].Success) //comment
      {
        StringReader reader = new StringReader(match.ToString());
        string line;
        StringBuilder sb = new StringBuilder();
        while ((line = reader.ReadLine()) != null)
        {
          if(sb.Length > 0)
          {
            sb.Append("\n");
          }
          sb.Append("<span class=\"rem\">");
          sb.Append(line);
          sb.Append("</span>");
        }
        return sb.ToString();
      }
      if(match.Groups[3].Success) //asp tag
      {
        return "<span class=\"asp\">" + match.ToString() + "</span>";
      }
      if(match.Groups[4].Success) //asp C# code
      {
        return csf.FormatSubCode(match.ToString());
      }
      if(match.Groups[5].Success) //tag delimiter
      {
        return "<span class=\"kwrd\">" + match.ToString() + "</span>";
      }
      if(match.Groups[6].Success) //html tagname
      {
        return "<span class=\"html\">" + match.ToString() + "</span>";
      }
      if(match.Groups[7].Success) //attributes
      {
        return attribRegex.Replace(match.ToString(), 
          new MatchEvaluator(this.AttributeMatchEval));
      }
      if(match.Groups[8].Success) //entity
      {
        return "<span class=\"attr\">" + match.ToString() + "</span>";
      }
      return match.ToString();
    }
  }
}