mrw-cxx/mrw/autostacktracelog4cxx.cpp

/** @file

    $Id$

    $Date$
    $Author$

    @copy © Marc Wäckerlin
    @license LGPL, see file <a href="license.html">COPYING</a>

    $Log$
    Revision 1.2  2004/08/28 16:21:25  marc
    mrw-c++-0.92 (mrw)
    - new file: version.cpp
    - new file header for all sources
    - work around warning in mrw::auto<T>
    - possibility to compile without log4cxx
    - work around bugs in demangle.h and libiberty.h
    - corrections in documentation
    - added simple tracing mechanism
    - more warnings
    - small corrections in Auto<>::Free and a new test for it
    - possibility to compile without stack trace

*/
#include <mrw/stacktrace.hpp>
#include <mrw/exception.hpp>
#include <exception>
#include <log4cxx/logger.h>

namespace mrw {

  /** @addtogroup StackTrace */
  //@{

  /** @addtogroup AutoTrace

      @section trclog4cxx Trace using the log4cxx Library

      If you link to the library @c libmrwexclog4cxx using a linker
      option such as: @c -lmrwexclog4cxx, then an unexpected handler
      is registered, that traces a fatal error using the log4cxx
      library. You don't need to change a single line in your code!

      The log4cxx library is located at:
       - http://logging.apache.org/log4cxx

      @note The configurator is not installed automatically. If you
      want to trace e.g. on the console, you have to call @c
      log4cxx::BasicConfigurator::configure(); as first statement in
      your @c main().
  */
  //@{

  /** @brief unexpected handler, that traces using log4cxx

      The unexpected handler is installed automatically when you link
      to @c -lmrwexclog4cxx. The implementation of this unexpected
      handler is as follows:

      @code
  void unexpected_log4cxx() {
    log4cxx::LoggerPtr logger = log4cxx::Logger::getLogger(_T("libmrw"));
    logger->fatal("Unexpected Exception", __FILE__, __LINE__);
    StackTrace::createSymtable();
    std::string st((std::string)StackTrace());
    try {
      throw;
    } catch (const mrw::exception& x) {
      logger->fatal(std::string("Reason:\n")+x.what()
                    +"\nStack:+\n"+x.stacktrace());
    } catch (const std::exception& x) {
      logger->fatal(std::string("Reason:\n")+x.what()
                    +"\nStack:\n"+st);
    } catch (...) {
      logger->fatal(std::string("Reason: **** not available ****")
                   +"\nStack:\n"+st);
    }
    throw std::bad_exception();
  }
      @endcode

  */
  void unexpected_log4cxx() {
    log4cxx::LoggerPtr logger = log4cxx::Logger::getLogger(_T("libmrw"));
    logger->fatal("Unexpected Exception", __FILE__, __LINE__);
    StackTrace::createSymtable();
    std::string st((std::string)StackTrace());
    try {
      throw;
    } catch (const mrw::exception& x) {
      logger->fatal(std::string("Reason:\n")+x.what()
                    +"\nStack:+\n"+x.stacktrace());
    } catch (const std::exception& x) {
      logger->fatal(std::string("Reason:\n")+x.what()
                    +"\nStack:\n"+st);
    } catch (...) {
      logger->fatal(std::string("Reason: **** not available ****")
                   +"\nStack:\n"+st);
    }
    throw std::bad_exception();
  }

  //@}
  //@}

  class AutoStackTrace {
    public:
    AutoStackTrace() {
      std::set_unexpected(&mrw::unexpected_log4cxx);
    }
  };

  // initialize stack traces (load symbols)
  static AutoStackTrace _autoStackTrace;

}