XMLHelpers.h

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// This file is part of the "NcML Module" project, a BES module designed
// to allow NcML files to be used to be used as a wrapper to add
// AIS to existing datasets of any format.
//
// Copyright (c) 2009 OPeNDAP, Inc.
// Author: Michael Johnson  <m.johnson@opendap.org>
//
// For more information, please also see the main website: http://opendap.org/
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
//
// Please see the files COPYING and COPYRIGHT for more information on the GLPL.
//
// You can contact OPeNDAP, Inc. at PO Box 112, Saunderstown, RI. 02874-0112.
#ifndef __NCML_MODULE__XML_HELPERS_H__
#define __NCML_MODULE__XML_HELPERS_H__

/*
 * This file contains a bunch of quick and dirty classes used to pass and store XML
 * attribute tables and namespace tables.
 *
 * class XMLUtil: conversions from xmlChar to string, mostly.
 * class XMLAttribute: holds namespace-augmented into on XML attribute.
 * class XMLAttributeMap: a container of XMLAttribute that allows lookups, etc.
 * class XMLNamespace: holds {prefix, uri} info for a namespace
 * class XMLNamespaceMap: a container of XMLNamespace's, typically from a single element.
 * class XMLNamespaceStack: container which is a stack of XMLNamespaceMap's to
 *                          allow a SAX lexical scoping operation to be done.
 */

#include <exception>
#include <libxml/xmlstring.h>
#include <string>
#include <vector>

namespace ncml_module
{

using std::string;
using std::vector;

struct XMLUtil
{
  static string xmlCharToString(const xmlChar* pChars);
  static void xmlCharToString(string& stringToFill, const xmlChar* pChars);
  static string xmlCharToStringFromIterators(const xmlChar* startPtr, const xmlChar* endPtr);
};

struct XMLAttribute
{
  XMLAttribute(const string& localName="", const string& value="", const string& prefix="", const string& nsURI="");

  XMLAttribute(const xmlChar** chunkOfFivePointers);
  XMLAttribute(const XMLAttribute& proto);
  XMLAttribute& operator=(const XMLAttribute& rhs);

  void fromSAX2NamespaceAttributes(const xmlChar** chunkOfFivePointers);

  string getQName() const;

  string getAsXMLString() const;

  static string getQName(const string& prefix, const string& localname);

  string localname;
  string prefix;
  string nsURI;
  string value;
};

class XMLAttributeMap
{
public:
  XMLAttributeMap();
  ~XMLAttributeMap();

  typedef vector<XMLAttribute>::const_iterator const_iterator;
  typedef vector<XMLAttribute>::iterator iterator;

  XMLAttributeMap::const_iterator begin() const;
  XMLAttributeMap::const_iterator end() const;

  bool empty() const;

  void clear();

  void addAttribute(const XMLAttribute& attribute);

  const string/*& jhrg 4/16/14*/getValueForLocalNameOrDefault(const string& localname, const string& defVal="") const;


  const XMLAttribute* getAttributeByLocalName(const string& localname) const;
  const XMLAttribute* getAttributeByQName(const string& qname) const;
  const XMLAttribute* getAttributeByQName(const string& prefix, const string& localname) const;

  string getAllAttributesAsString() const;

private: // helpers

  XMLAttributeMap::iterator findByQName(const string& qname);

private: // data rep
  // We don't expect many, vector is fast to search and contiguous in memory for few items.
  vector<XMLAttribute> _attributes;
};

struct XMLNamespace
{
  XMLNamespace(const string& prefix="", const string& uri="");
  XMLNamespace(const XMLNamespace& proto);
  XMLNamespace& operator=(const XMLNamespace& rhs);

  void fromSAX2Namespace(const xmlChar** namespaces);

  string getAsAttributeString() const;

  string prefix;
  string uri;
};

class XMLNamespaceMap
{
public:
  XMLNamespaceMap();
  ~XMLNamespaceMap();
  XMLNamespaceMap(const XMLNamespaceMap& proto);
  XMLNamespaceMap& operator=(const XMLNamespaceMap& rhs);

  void fromSAX2Namespaces(const xmlChar** pNamespaces, int numNamespaces);

  string getAllNamespacesAsAttributeString() const;

  typedef vector<XMLNamespace>::const_iterator const_iterator;

  XMLNamespaceMap::const_iterator begin() const;
  XMLNamespaceMap::const_iterator end() const;

  XMLNamespaceMap::const_iterator find(const string& prefix) const;

  bool isInMap(const string& prefix) const;

  void addNamespace(const XMLNamespace& ns);

  void clear();
  bool empty() const;

private: // helpers

  typedef vector<XMLNamespace>::iterator iterator;

  XMLNamespaceMap::iterator findNonConst(const string& prefix);

private:
  vector<XMLNamespace> _namespaces;
};

class XMLNamespaceStack
{
public:
  XMLNamespaceStack();
  ~XMLNamespaceStack();
  XMLNamespaceStack(const XMLNamespaceStack& proto);
  XMLNamespaceStack& operator=(const XMLNamespaceStack& rhs);

  void push(const XMLNamespaceMap& nsMap);
  void pop();
  const XMLNamespaceMap& top() const;

  bool empty() const;
  void clear();

  // Change the direction since we use the vector as a stack.
  typedef vector<XMLNamespaceMap>::const_reverse_iterator const_iterator;

  XMLNamespaceStack::const_iterator begin() const;
  XMLNamespaceStack::const_iterator end() const;

  void getFlattenedNamespacesUsingLexicalScoping(XMLNamespaceMap& nsFlattened) const;

private: // helpers

  static void addMissingNamespaces(XMLNamespaceMap& intoMap, const XMLNamespaceMap& fromMap);

private: // data rep
  // Vector for easy scanning.
  vector<XMLNamespaceMap> _stack;
};

} // namespace ncml_module
#endif // __NCML_MODULE__XML_HELPERS_H__