//==========================================================================
//  SAXPARSER.H - part of
//                     OMNeT++/OMNEST
//            Discrete System Simulation in C++
//
//==========================================================================

/*--------------------------------------------------------------*
  Copyright (C) 2002-2017 Andras Varga
  Copyright (C) 2006-2017 OpenSim Ltd.

  This file is distributed WITHOUT ANY WARRANTY. See the file
  `license' for details on this and other legal matters.
*--------------------------------------------------------------*/



#ifndef __OMNETPP_NEDXML_SAXPARSER_H
#define __OMNETPP_NEDXML_SAXPARSER_H

#include <cstdio>
#include "nedxmldefs.h"

namespace omnetpp {
namespace nedxml {

class SAXParser;


/**
 * @brief Base class for SAX event handlers needed by SAXParser.
 * This is a simplified SAX handler interface.
 *
 * All event handlers provided by this class are empty, one must
 * subclass SAXHandler and redefine the event handler to make them
 * do something useful.
 *
 * @ingroup XMLParser
 */
class NEDXML_API SAXHandler
{
    friend class SAXParser;
  protected:
    SAXParser *parser;

    // internal: called from SAXParser::setHandler()
    virtual void setParser(SAXParser *p) {parser=p;}

  public:
    /**
     * Constructor
     */
    SAXHandler() {parser=nullptr;}

    /**
     * Destructor
     */
    virtual ~SAXHandler() {}

    /**
     * Called by the parser on SAX StartElement events.
     */
    virtual void startElement(const char *name, const char **atts)  {}

    /**
     * Called by the parser on SAX EndElement events.
     */
    virtual void endElement(const char *name)  {}

    /**
     * Called by the parser on SAX CharacterData events.
     */
    virtual void characterData(const char *s, int len)  {}

    /**
     * Called by the parser on SAX ProcessingInstruction events.
     */
    virtual void processingInstruction(const char *target, const char *data)  {}

    /**
     * Called by the parser on SAX Comment events.
     */
    virtual void comment(const char *data)  {}

    /**
     * Called by the parser on SAX CDataStart events.
     */
    virtual void startCdataSection()  {}

    /**
     * Called by the parser on SAX CDataEnd events.
     */
    virtual void endCdataSection()  {}
};


/**
 * @brief Wraps XML SAX parsers.
 *
 * Expat and LibXML are supported at the moment, decided at compile-time.
 * DTD validation is supported with LibXML.
 *
 * One must provide a SAXHandler for this class to be useful.
 *
 * @ingroup XMLParser
 */
class NEDXML_API SAXParser
{
  protected:
    char errorText[512];
    SAXHandler *saxHandler;
    void *currentParser;

  protected:
    // allows for a common implementation of parse() and parseContent()
    bool doParse(const char *filename, const char *content);

  public:
    /**
     * Constructor
     */
    SAXParser();

    /**
     * Install a SAX handler into the parser.
     */
    void setHandler(SAXHandler *sh);

    /**
     * Parse XML input read from the given file. Methods of the SAX handler
     * will be called as the parser processes the file. Returns false if
     * there was an error; in that case use getErrorMessage() to learn the
     * cause of the error.
     */
    bool parse(const char *filename);

    /**
     * Parse the given string as XML content. Methods of the SAX handler
     * will be called as the parser processes the file. Returns false if
     * there was an error; in that case use getErrorMessage() to learn the
     * cause of the error.
     */
    bool parseContent(const char *content);

    /**
     * Returns the current line number in the input. Can be called from SAX handler code.
     */
    int getCurrentLineNumber();

    /**
     * Can be called after parse() returned false. Returns the error description.
     */
    const char *getErrorMessage()  {return errorText;}
};

} // namespace nedxml
}  // namespace omnetpp


#endif