logstream.h

// -*- mode: c++;
#ifndef logstream_h
#define logstream_h

#include "streamlog/prefix.h"

#include <iostream>
#include <map>

namespace streamlog{

  class prefix_base ;
  class logbuffer ;
  class logscope ;


  class logstream {

    friend class logscope ;
    friend class logbuffer ;


    typedef std::map< std::string,  unsigned > LevelMap ;

  public :

    logstream() ; 

    ~logstream() ;

    void init( std::ostream& os , const std::string name ) ;

    template<class T>
    inline bool write() {
      
      // dont' call chek_level if T::active == false
      return (  T::active   &&    check_level<T>()  ) ;
    }

    template<class T>
    inline bool would_write() {
      
      return (  T::active   &&  T::level >= _level ) ;
    }

    std::ostream& operator()() ;

    template <class T>
    void addLevelName() {

      _map[ T::name() ] = T::level ;
    }


    // interface for friend classes: scope and logbuffer

  protected:

    void setLevel( unsigned level ) { _level = level ; } 

    unsigned setLevel( const std::string& levelName )  ; 

    prefix_base* prefix() { return _prefix ; }

    template<class T>
    bool check_level() {
      
      if( T::level >= _level ){
        _active = true ;
        _prefix->_levelName = T::name() ;
      }
      return _active ;
    }


  private:

    class nullstream :  public std::ostream {
    public:
      nullstream() : std::ios( 0 ), std::ostream( 0 ) {} ;
    } ;
  

    nullstream* _ns ;    // the nullstream
    std::ostream* _os ; // wrapper for actual ostream
    unsigned _level ;   // current log level 
    bool _active ;      // boolean helper 
    logbuffer* _lb ;        // log buffer adds prefix to everu log message
    prefix_base* _prefix ;  // prefix formatter
    LevelMap _map ;         // string map of level names
    
  } ;

  extern logstream out ;

}
#endif