log.cc

//------------------------------------------------------------------------------
// This file is part of the OpenStructure project <www.openstructure.org>
//
// Copyright (C) 2008-2010 by the OpenStructure authors
//
// 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 3.0 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
//------------------------------------------------------------------------------
#include <iostream>
#include <fstream>


#include <ost/log.hh>

namespace ost {

Logger& Log = Logger::Instance();

namespace {

  class DevNull: public std::streambuf {
  protected:
    virtual int_type overflow(int_type c) {return c;}
    virtual std::streamsize xsputn(const char* s, std::streamsize num) {return num;}
  };

} // anon ns


Logger& Logger::Instance()
{
  static Logger inst;
  return inst;
}

Logger::Logger():
  level_(0),
  level_stack_(),
  null_(new DevNull()),
  stream_(0),
  ostream_stack_()
{
  ostream_stack_.push(new std::ostream(std::cerr.rdbuf()));
  stream_.rdbuf(ostream_stack_.top()->rdbuf());
}

Logger::Logger(const Logger&):
  level_(0),
  level_stack_(),
  null_(0),
  stream_(0),
  ostream_stack_()
{
  ostream_stack_.push(new std::ostream(std::cerr.rdbuf()));
  stream_.rdbuf(ostream_stack_.top()->rdbuf());
}

Logger& Logger::operator=(const Logger&)
{
  return *this;
}

void Logger::PushVerbosityLevel(int l)
{
  level_stack_.push(l);
  level_=l;
}

void Logger::PopVerbosityLevel()
{
  if(!level_stack_.empty()) {
    level_stack_.pop();
  }
  if(level_stack_.empty()) {
    level_=1;
  } else {
    level_=level_stack_.top();
  }
}

std::ostream& Logger::operator()(enum LogLevel l)
{
  if(l<=level_) {
    return stream_;
  }
  return null_;
}

void Logger::PushFile(const String& fn)
{
  ostream_stack_.push(new std::ofstream(fn.c_str()));
  stream_.rdbuf(ostream_stack_.top()->rdbuf());
}

void Logger::PopFile()
{
  if(ostream_stack_.size()>1) {
    delete ostream_stack_.top();
    ostream_stack_.pop();
    stream_.rdbuf(ostream_stack_.top()->rdbuf());
  }
}


} // ns