/*
 * $Header: /home/cvs/jakarta-tomcat/src/share/org/apache/jasper/compiler/Mark.java,v 1.6 2004/02/23 06:22:36 billbarker Exp $
 * $Revision: 1.6 $
 * $Date: 2004/02/23 06:22:36 $
 *
 *
 *  Copyright 1999-2004 The Apache Software Foundation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package org.apache.jasper.compiler;

import java.util.Stack;

/**
 * Mark represents a point in the JSP input. 
 *
 * @author Anil K. Vijendran
 */
public final class Mark {
    int cursor, line, col;	// position within current stream
    int fileid;			// fileid of current stream
    String fileName;            // name of the current file
    String baseDir;		// directory of file for current stream
    char[] stream = null;	// current stream
    Stack includeStack = null;	// stack of stream and stream state of streams
				//   that have included current stream
    String encoding = null;	// encoding of current file
    private JspReader reader;	// reader that owns this mark 
				//   (so we can look up fileid's)


    /**
     * Keep track of parser before parsing an included file.
     * This class keeps track of the parser before we switch to parsing an
     * included file. In other words, it's the parser's continuation to be
     * reinstalled after the included file parsing is done.
     */
    class IncludeState {
	int cursor, line, col;
	int fileid;
	String fileName;
	String baseDir;
	String encoding;
	char[] stream = null;

	IncludeState(int inCursor, int inLine, int inCol, int inFileid, 
		     String name, String inBaseDir, String inEncoding,
		     char[] inStream) 
	{
	    cursor = inCursor;
	    line = inLine;
	    col = inCol;
	    fileid = inFileid;
	    fileName = name;
	    baseDir = inBaseDir;
	    encoding = inEncoding;
	    stream = inStream;
	}
    }


    /**
    * Creates a new mark
    * @param inReader JspReader this mark belongs to
    * @param inStream current stream for this mark
    * @param inFileid id of requested jsp file
    * @param inEncoding encoding of current file
    * @param inBaseDir base directory of requested jsp file
    */
    Mark(JspReader reader, char[] inStream, int fileid, String name,
	 String inBaseDir, String inEncoding) 
    {
	this.reader = reader;
	this.stream = inStream;
	this.cursor = this.line = this.col = 0;
	this.fileid = fileid;
	this.fileName = name;
	this.baseDir = inBaseDir;
	this.encoding = inEncoding;
	this.includeStack = new Stack();
    }
	
    Mark(Mark other) {
	this.reader = other.reader;
	this.stream = other.stream;
	this.fileid = other.fileid;
	this.fileName = other.fileName;
	this.cursor = other.cursor;
	this.line = other.line;
	this.col = other.col;
	this.baseDir = other.baseDir;
	this.encoding = other.encoding;

	// clone includeStack without cloning contents
	includeStack = new Stack();
	for ( int i=0; i < other.includeStack.size(); i++ ) {
  	    includeStack.addElement( other.includeStack.elementAt(i) );
	}
    }
	    
    /** Sets this mark's state to a new stream.
     * It will store the current stream in it's includeStack.
     * @param inStream new stream for mark
     * @param inFileid id of new file from which stream comes from
     * @param inBaseDir directory of file
	 * @param inEncoding encoding of new file
     */
    public void pushStream(char[] inStream, int inFileid, String name,
			   String inBaseDir, String inEncoding) 
    {

	// store current state in stack
	includeStack.push(new IncludeState(cursor, line, col, fileid, fileName, baseDir, 
					   encoding, stream) );

	// set new variables
	cursor = 0;
	line = 0;
	col = 0;
	fileid = inFileid;
	fileName = name;
	baseDir = inBaseDir;
	encoding = inEncoding;
	stream = inStream;
    }



    /** Restores this mark's state to a previously stored stream.
     */
    public boolean popStream() {
	// make sure we have something to pop
	if ( includeStack.size() <= 0 ) return false;

	// get previous state in stack
	IncludeState state = (IncludeState) includeStack.pop( );

	// set new variables
	cursor = state.cursor;
	line = state.line;
	col = state.col;
	fileid = state.fileid;
	fileName = state.fileName;
	baseDir = state.baseDir;
	stream = state.stream;
	return true;
    }



    public String toString() {
	return getFile()+"("+line+","+col+")";
    }

    public String getFile() {
        return this.fileName;
    }
    
    public String toShortString() {
        return "("+line+","+col+")";
    }

    public boolean equals(Object other) {
	if (other instanceof Mark) {
	    Mark m = (Mark) other;
	    return this.reader == m.reader && this.fileid == m.fileid 
		&& this.cursor == m.cursor && this.line == m.line 
		&& this.col == m.col;
	} 
	return false;
    }
}