XMLTagHandler.h

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/**********************************************************************
 
  Audacity: A Digital Audio Editor
 
  XMLTagHandler.h
 
  Dominic Mazzoni
  Vaughan Johnson
  Dmitry Vedenko
 
  The XMLTagHandler class is an interface which should be implemented by
  classes which wish to be able to load and save themselves
  using XML files.
 
  The XMLValueChecker class implements static bool methods for checking
  input values from XML files.
 
**********************************************************************/
#ifndef __AUDACITY_XML_TAG_HANDLER__
#define __AUDACITY_XML_TAG_HANDLER__
 
#include <string_view>
#include <vector>
 
#include "XMLWriter.h"
#include "XMLAttributeValueView.h"
 
 
class XML_API XMLValueChecker
{
public:
   static bool IsGoodFileName(const FilePath & strFileName, const FilePath & strDirName = {});
   static bool IsGoodFileString(const FilePath &str);
   static bool IsGoodSubdirName(const FilePath & strSubdirName, const FilePath & strDirName = {});
   static bool IsGoodPathName(const FilePath & strPathName);
   static bool IsGoodPathString(const FilePath &str);
};
 
using Attribute = std::pair<std::string_view, XMLAttributeValueView>;
using AttributesList = std::vector<Attribute>;
 
class XML_API XMLTagHandler /* not final */ {
 public:
   XMLTagHandler(){};
   virtual ~XMLTagHandler(){};
   //
   // Methods to override
   //
 
   // This method will be called on your class if your class has
   // been registered to handle this particular tag.  Parse the
   // tag and the attribute-value pairs (null-terminated), and
   // return true on success, and false on failure.  If you return
   // false, you will not get any calls about children.
   virtual bool HandleXMLTag(const std::string_view& tag, const AttributesList& attrs) = 0;
 
   // This method will be called when a closing tag is encountered.
   // It is optional to override this method.
   virtual void HandleXMLEndTag(const std::string_view& WXUNUSED(tag)) {}
 
   // This method will be called when element content has been
   // encountered.
   // It is optional to override this method.
   virtual void HandleXMLContent(const std::string_view& WXUNUSED(content)) {}
 
   // If the XML document has children of your tag, this method
   // should be called.  Typically you should construct a NEW
   // object for the child, insert it into your own local data
   // structures, and then return it.  If you do not wish to
   // handle this child, return NULL and it will be ignored.
   virtual XMLTagHandler *HandleXMLChild(const std::string_view& tag) = 0;
 
   // These functions receive data from expat.  They do charset
   // conversion and then pass the data to the handlers above.
   void ReadXMLEndTag(const char *tag);
   void ReadXMLContent(const char *s, int len);
   XMLTagHandler *ReadXMLChild(const char *tag);
};
 
#endif // define __AUDACITY_XML_TAG_HANDLER__