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/*
* AbstractXMLParser.h
* Dasher
*
* Created by Alan Lawrence on 17/03/2011.
* Copyright 2011 Cavendish Laboratory. All rights reserved.
*
*/
#ifndef __ABSTRACT_XML_PARSER_H__
#define __ABSTRACT_XML_PARSER_H__
#include "../Common/Common.h"
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "Messages.h"
#include <string>
#include <expat.h>
#include <iostream>
class AbstractParser {
public:
AbstractParser(CMessageDisplay *pMsgs) : m_pMsgs(pMsgs) { }
///Utility method: constructs an ifstream to read from the specified file,
/// then calls Parse(string&,istream&,bool) with the description 'file://strPath'
virtual bool ParseFile(const std::string &strPath, bool bUser);
/// \param strDesc string to display to user to identify the source of this data,
/// if there is an error. (Suggest: use a url, e.g. file://...)
/// \param bUser if True, the file is from a user location (editable), false if from a
/// system one. (Some subclasses treat the data differently according to which of these
/// it is from.)
virtual bool Parse(const std::string &strDesc, std::istream &in, bool bUser) = 0;
protected:
///The MessageDisplay to use to inform the user. Subclasses should use this
/// too for any (e.g. semantic) errors they may detect.
CMessageDisplay * const m_pMsgs;
};
///Basic wrapper over (Expat) XML Parser, handling file IO and wrapping C++
/// virtual methods over C callbacks. Subclasses must implement methods to
/// handle actual tags.
class AbstractXMLParser : public AbstractParser {
public:
///Parse (the whole) file - done in chunks to avoid loading the whole thing into memory.
/// Any errors _besides_ file-not-found, will be passed to m_pMsgs as modal messages.
virtual bool Parse(const std::string &strDesc, std::istream &in, bool bUser);
protected:
///Create an AbstractXMLParser which will use the specified MessageDisplay to
/// inform the user of any errors.
AbstractXMLParser(CMessageDisplay *pMsgs);
///Subclasses may call to get the description of the current file
const std::string &GetDesc() {return m_strDesc;}
///Subclasses may call to determine if the current file is from a user location
bool isUser();
///Subclass should override to handle a start tag
virtual void XmlStartHandler(const XML_Char *name, const XML_Char **atts)=0;
///Subclass should override to handle an end tag
virtual void XmlEndHandler(const XML_Char *name)=0;
///Subclass may override to handle character data; the default implementation does nothing.
///\param str pointer to string data, note is NOT null-terminated
///\param len number of bytes to read from pointer
virtual void XmlCData(const XML_Char *str, int len);
///Utility function provided for subclasses wishing to perform XML _output_.
// & to & < to < and > to > and if (Attribute) ' to ' and " to "
/// \param Input string to escape, will be updated in-place.
void XML_Escape(std::string &Input, bool Attribute);
private:
/// The actual callbacks passed to the expat library.
/// These just convert the void* we passed to the library back into
/// an instance pointer, to get a C++ class to work with a plain C library.
static void XML_StartElement(void *userData, const XML_Char * name, const XML_Char ** atts);
static void XML_EndElement(void *userData, const XML_Char * name);
static void XML_CharacterData(void *userData, const XML_Char * s, int len);
bool m_bUser;
std::string m_strDesc;
};
#endif
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