Xml.h

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#ifndef ZYPP_BASE_XML_H
#define ZYPP_BASE_XML_H
 
#include <iosfwd>
#include <string>
#include <vector>
#include <list>
#include <set>
#include <map>
 
#include <zypp-core/base/Easy.h>
#include <zypp-core/base/String.h>
#include <zypp-core/parser/xml/XmlEscape.h>

namespace zypp
{
  namespace xmlout
  {
    using xml::escape;
    using xml::unescape;

    template <class Tp>
    std::string asXmlNodeAttr( const Tp & val_r )
    { return asString( val_r ); }

    struct NodeAttr : public std::pair<std::string,std::string>
    {
      using Pair = std::pair<std::string, std::string>;
 
      template <typename Tp>
      NodeAttr( std::string key_r, const Tp & val_r )
      : Pair( std::move(key_r), asXmlNodeAttr(val_r) )
      {}
 
      NodeAttr( std::string key_r, std::string val_r )
      : Pair( std::move(key_r), std::move(val_r) )
      {}
    };


    struct Node
    {
      NON_COPYABLE_BUT_MOVE( Node );
      using Attr = NodeAttr;
 
      struct OptionalContentType {}; 
      static constexpr OptionalContentType optionalContent = OptionalContentType();

      Node( std::ostream & out_r, std::string name_r, const std::initializer_list<Attr> & attrs_r = {} )
      : _out( out_r ), _name( std::move(name_r) ), _hasContent( true )
      { printStart( attrs_r ); }

      Node( std::ostream & out_r, std::string name_r, Attr attr_r )
        : Node( out_r, std::move(name_r), { std::move(attr_r) } )
      {}

      Node( std::ostream & out_r, std::string name_r, OptionalContentType, const std::initializer_list<Attr> & attrs_r = {} )
      : _out( out_r ), _name( std::move(name_r) ), _hasContent( false )
      { printStart( attrs_r ); }

      Node( std::ostream & out_r, std::string name_r, OptionalContentType, Attr attr_r )
      : Node( out_r, std::move(name_r), optionalContent, { std::move(attr_r) } )
      {}

      ~Node()
      {
        if ( isComment() )
          _out.get()  << "-->";
        else
        {
          if ( _hasContent )
            _out.get()  << "</" << _name << ">";
          else
            _out.get()  << "/>";
        }
      }

      struct HasContentException{};

      Node & addAttr( const std::initializer_list<Attr> & attrs_r = {} )
      {
        if ( _hasContent )
          throw HasContentException();
        printAttr( attrs_r );
        return *this;
      }

      Node & addAttr( const Attr & attr_r )
      { return addAttr( { attr_r } ); }
 

      std::ostream & operator*()
      {
        if ( ! _hasContent )
        {
          _hasContent = true;
          if ( isComment() )
            _out.get()  << "|";
          else
            _out.get()  << ">";
        }
        return _out;
      }
 
    private:
      void printStart( const std::initializer_list<Attr> & attrs_r )
      {
        if ( _name.empty() || _name[0] == '!' )
        {
          _out.get()  << "<!--" << _name;
          _name.clear();   // a comment
        }
        else
          _out.get()  << "<" << _name;
 
        printAttr( attrs_r );
 
        if ( !isComment() && _hasContent )
          _out.get()  << ">";
      }
 
      void printAttr( const std::initializer_list<Attr> & attrs_r )
      {
        for ( const auto & pair : attrs_r )
          _out.get() << " " << pair.first << "=\"" << xml::escape( pair.second ) << "\"";
      }
 
      bool isComment() const
      { return _name.empty();  }
 
    private:
      // use a reference wrapper, otherwise the defaulted move operator is deleted
      std::reference_wrapper<std::ostream> _out;
      std::string _name;
      bool _hasContent;
    };


    inline std::ostream & node( std::ostream & out_r, const std::string & name_r, const std::initializer_list<Node::Attr> & attrs_r = {} )
    {
      Node( out_r, name_r, Node::optionalContent, attrs_r );
      return out_r;
    }

    inline std::ostream & node( std::ostream & out_r, const std::string & name_r, Node::Attr attr_r )
    { return node( out_r, name_r, { std::move(attr_r) } ); }
 
  } // namespace xmlout


  template <class Tp>
  inline std::ostream & dumpAsXmlOn( std::ostream & str, const Tp & obj, const std::string & name_r )
  {
    xmlout::Node guard( str, name_r, xmlout::Node::optionalContent );
    const std::string & content( asString( obj ) );
    if ( ! content.empty() ) *guard << xml::escape( content );
    return str;
  }

  //
} // namespace zypp
#endif // ZYPP_BASE_XML_H