mono/mcs/class/System.Web/System.Web.Compilation/AspParser.cs

//
// System.Web.Compilation.AspParser
//
// Authors:
//	Gonzalo Paniagua Javier ([email protected])
//
// (C) 2002,2003 Ximian, Inc (http://www.ximian.com)
//
using System;
using System.Collections;
using System.IO;
using System.Text;

namespace System.Web.Compilation
{
	delegate void ParseErrorHandler (ILocation location, string message);
	delegate void TextParsedHandler (ILocation location, string text);
	delegate void TagParsedHandler (ILocation location, TagType tagtype, string id, TagAttributes attributes);

	class AspParser : ILocation
	{
		AspTokenizer tokenizer;
		int beginLine, endLine;
		int beginColumn, endColumn;
		int beginPosition, endPosition;
		string filename;
		string fileText;
		string verbatimID;

		public AspParser (string filename, TextReader input)
		{
			this.filename = filename;
			fileText = input.ReadToEnd ();
			StringReader reader = new StringReader (fileText);
			tokenizer = new AspTokenizer (reader);
		}

		public int BeginLine {
			get { return beginLine; }
		}

		public int BeginColumn {
			get { return beginColumn; }
		}

		public int EndLine {
			get { return endLine; }
		}

		public int EndColumn {
			get { return endColumn; }
		}

		public string PlainText {
			get {
				if (beginPosition >= endPosition)
					return null;

				return fileText.Substring (beginPosition, endPosition - beginPosition);
			}
		}

		public string Filename {
			get { return filename; }
		}

		public string VerbatimID {
			set {
				tokenizer.Verbatim = true;
				verbatimID = value.ToUpper ();
			}
		}
		
		bool Eat (int expected_token)
		{
			if (tokenizer.get_token () != expected_token) {
				tokenizer.put_back ();
				return false;
			}

			endLine = tokenizer.EndLine;
			endColumn = tokenizer.EndColumn;
			return true;
		}

		void BeginElement ()
		{
			beginLine = tokenizer.BeginLine;
			beginColumn = tokenizer.BeginColumn;
			beginPosition = tokenizer.Position - 1;
		}

		void EndElement ()
		{
			endLine = tokenizer.EndLine;
			endColumn = tokenizer.EndColumn;
			endPosition = tokenizer.Position;
		}

		public void Parse ()
		{
			int token;
			string id;
			TagAttributes attributes;
			TagType tagtype;
			StringBuilder text =  new StringBuilder ();

			while ((token = tokenizer.get_token ()) != Token.EOF) {
				BeginElement ();

				if (tokenizer.Verbatim){
					string end_verbatim = "</" + verbatimID + ">";
					string verbatim_text = GetVerbatim (token, end_verbatim);

					if (verbatim_text == null)
						OnError ("Unexpected EOF processing " + verbatimID);

					tokenizer.Verbatim = false;

					EndElement ();
					endPosition -= end_verbatim.Length;
					OnTextParsed (verbatim_text);
					beginPosition = endPosition;
					endPosition += end_verbatim.Length;
					OnTagParsed (TagType.Close, verbatimID, null);
					continue;
				}
				
				if (token == '<') {
					GetTag (out tagtype, out id, out attributes);
					EndElement ();
					if (tagtype == TagType.ServerComment)
						continue;

					if (tagtype == TagType.Text)
						OnTextParsed (id);
					else
						OnTagParsed (tagtype, id, attributes);

					continue;
				}

				text.Length = 0;
				do {
					text.Append (tokenizer.Value);
					token = tokenizer.get_token ();
				} while (token != '<' && token != Token.EOF);

				tokenizer.put_back ();
				EndElement ();
				OnTextParsed (text.ToString ());
			}
		}

		void GetTag (out TagType tagtype, out string id, out TagAttributes attributes)
		{
			int token = tokenizer.get_token ();

			tagtype = TagType.ServerComment;
			id = null;
			attributes = null;
			switch (token){
			case '%':
				GetServerTag (out tagtype, out id, out attributes);
				break;
			case '/':
				if (!Eat (Token.IDENTIFIER))
					OnError ("expecting TAGNAME");

				id = tokenizer.Value;
				if (!Eat ('>'))
					OnError ("expecting '>'");

				tagtype = TagType.Close;
				break;
			case '!':
				bool double_dash = Eat (Token.DOUBLEDASH);
				if (double_dash)
					tokenizer.put_back ();

				tokenizer.Verbatim = true;
				string end = double_dash ? "-->" : ">";
				string comment = GetVerbatim (tokenizer.get_token (), end);
				tokenizer.Verbatim = false;
				if (comment == null)
					OnError ("Unfinished HTML comment/DTD");

				tagtype = TagType.Text;
				id = "<!" + comment + end;
				break;
			case Token.IDENTIFIER:
				id = tokenizer.Value;
				attributes = GetAttributes ();
				tagtype = TagType.Tag;
				if (Eat ('/') && Eat ('>'))
					tagtype = TagType.SelfClosing;
				else if (!Eat ('>'))
					OnError ("expecting '>'");

				break;
			default:
				tagtype = TagType.Text;
				id = "<" + tokenizer.Value;
				break;
			}
		}

		TagAttributes GetAttributes ()
		{
			int token;
			TagAttributes attributes;
			string id;

			attributes = new TagAttributes ();
			while ((token = tokenizer.get_token ())  != Token.EOF){
				if (token != Token.IDENTIFIER)
					break;
				id = tokenizer.Value;
				if (Eat ('=')){
					if (Eat (Token.ATTVALUE)){
						attributes.Add (id, tokenizer.Value);
					} else {
						//TODO: support data binding syntax without quotes
						OnError ("expected ATTVALUE");
						return null;
					}
					
				} else {
					attributes.Add (id, null);
				}
			}

			tokenizer.put_back ();
			if (attributes.Count == 0)
				return null;

			return attributes;
		}

		string GetVerbatim (int token, string end)
		{
			StringBuilder vb_text = new StringBuilder ();
			int i = 0;

			if (tokenizer.Value.Length > 1){
				// May be we have a put_back token that is not a single character
				vb_text.Append (tokenizer.Value);
				token = tokenizer.get_token ();
			}

			while (token != Token.EOF){
				if (Char.ToUpper ((char) token) == end [i]){
					if (++i >= end.Length)
						break;
					token = tokenizer.get_token ();
					continue;
				} else if (i > 0) {
					for (int j = 0; j < i; j++)
						vb_text.Append (end [j]);
					i = 0;
				}

				vb_text.Append ((char) token);
				token = tokenizer.get_token ();
			} 

			return RemoveComments (vb_text.ToString ());
		}

		string RemoveComments (string text)
		{
			int end;
			int start = text.IndexOf ("<%--");

			while (start != -1) {
				end = text.IndexOf ("--%>");
				if (end == -1 || end <= start + 1)
					break;

				text = text.Remove (start, end - start + 4);
				start = text.IndexOf ("<%--");
			}

			return text;
		}

		void GetServerTag (out TagType tagtype, out string id, out TagAttributes attributes)
		{
			string inside_tags;

			if (Eat ('@')){
				tagtype = TagType.Directive;
				id = "";
				if (Eat (Token.DIRECTIVE))
					id = tokenizer.Value;

				attributes = GetAttributes ();
				if (!Eat ('%') || !Eat ('>'))
					OnError ("expecting '%>'");

				return;
			}
			
			if (Eat (Token.DOUBLEDASH)) {
				tokenizer.Verbatim = true;
				inside_tags = GetVerbatim (tokenizer.get_token (), "--%>");
				tokenizer.Verbatim = false;
				id = null;
				attributes = null;
				tagtype = TagType.ServerComment;
				return;
			}

			bool varname;
			bool databinding;
			varname = Eat ('=');
			databinding = !varname && Eat ('#');

			tokenizer.Verbatim = true;
			inside_tags = GetVerbatim (tokenizer.get_token (), "%>");
			tokenizer.Verbatim = false;
			id = inside_tags;
			attributes = null;
			tagtype = (databinding ? TagType.DataBinding :
				  (varname ? TagType.CodeRenderExpression : TagType.CodeRender));
		}

		public event ParseErrorHandler Error;
		public event TagParsedHandler TagParsed;
		public event TextParsedHandler TextParsed;

		void OnError (string msg)
		{
			if (Error != null)
				Error (this, msg);
		}

		void OnTagParsed (TagType tagtype, string id, TagAttributes attributes)
		{
			if (TagParsed != null)
				TagParsed (this, tagtype, id, attributes);
		}

		void OnTextParsed (string text)
		{
			if (TextParsed != null)
				TextParsed (this, text);
		}
	}

}