log_base.h

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#ifndef LOG_BASE_CLASS
#define LOG_BASE_CLASS

/*****************************************************************************\
*                                                                             *
*  Name   : log_base                                                          *
*  Author : Chris Koeritz                                                     *
*                                                                             *
*******************************************************************************
* Copyright (c) 1996-$now By Author.  This program is free software; you can  *
* redistribute it and/or modify it under the terms of the GNU General Public  *
* License as published by the Free Software Foundation; either version 2 of   *
* the License or (at your option) any later version.  This is online at:      *
*     http://www.fsf.org/copyleft/gpl.html                                    *
* Please send any updates to: fred@gruntose.com                               *
\*****************************************************************************/

#include "object_base.h"
#include "program_wide_logger.h"
#include "utility.h"


class log_base : public virtual object_base
{
public:
  log_base();  

  log_base(const log_base &to_copy);  

  virtual ~log_base();  

  log_base &operator =(const log_base &to_copy); 


  enum KNOWN_FILTERS {
    // these two filters are predefined and their meaning cannot be changed.
    ALWAYS_PRINT = common::ALWAYS_PRINT,  
    NEVER_PRINT = common::NEVER_PRINT  
  };

  virtual void add_filter(int new_filter);

  virtual void remove_filter(int old_filter);

  virtual bool member(int filter_to_check);

  virtual void clear_filters();

  virtual int_set filter_set();


  enum line_ending {
    LF_AT_END = -15,  
    CRLF_AT_END,  
    NO_ENDING  
  };

  virtual line_ending eol();
  virtual void eol(line_ending to_set);

  virtual istring get_ending();
  virtual void get_ending(istring &to_end);

  // the real core of the log_base is the log() method, which all derived
  // classes MUST provide.

  virtual outcome log(const istring &info, int filter = ALWAYS_PRINT) = 0;

  outcome log(const char *info, int filter = ALWAYS_PRINT);
  inline log_base &operator <<(const istring &info) { log(info); return *this; }
  inline log_base &operator <<(const char *info) { log(info); return *this; }

  // helpful methods for dealing with line endings.

  static const char *string_for_ending(line_ending ending);
  static line_ending pick_ending_for_platform();
  static const char *platform_ending();

  // nitty-gritty special functions...

  void stuff_filter_set(const int_set &new_set);

private:
  mutex *_lock;  
  int_set *_filter_set;  
  line_ending _ending;  
};


// these macros can assist in logging.  they rely on the base class for
// logging services.  note that it is often convenient to customize these
// to yield a simpler macro name per project, such as PRINT or LOG.


#define FILTER_LOG(the_logger, to_log, filter) { \
  if (the_logger.member(filter)) { \
    the_logger.log(to_log, filter); \
  } \
}

#define EMERGENCY_LOG(the_logger, to_log) \
  FILTER_LOG(the_logger, to_log, log_base::ALWAYS_PRINT)

#define STAMPED_FILTER_LOG(the_logger, to_log, filter) { \
  if (the_logger.member(filter)) { \
    istring temp_log = to_log; \
    if (temp_log.length()) \
      temp_log.insert(0, utility::timestamp(true, true)); \
    the_logger.log(temp_log, filter); \
  } \
}
#define STAMPED_EMERGENCY_LOG(the_logger, to_log) \
  STAMPED_FILTER_LOG(the_logger, to_log, log_base::ALWAYS_PRINT)

/* These add a class and function name to the log entry. */
#define CLASS_FILTER_LOG(the_logger, to_log, filter) { \
  update_current_stack_frame_line_number(__LINE__); \
  if (the_logger.member(filter)) { \
    istring temp_log = to_log; \
    if (temp_log.length()) { \
      temp_log.insert(0, utility::timestamp(true, true)); \
      BASE_FUNCTION(func); \
      temp_log += " ["; \
      temp_log += function_name; \
      temp_log += "]"; \
    } \
    the_logger.log(temp_log, filter); \
  } \
  update_current_stack_frame_line_number(__LINE__); \
}
#define CLASS_EMERGENCY_LOG(the_logger, to_log) \
  CLASS_FILTER_LOG(the_logger, to_log, log_base::ALWAYS_PRINT)


#define INSTANCE_FILTER_LOG(the_logger, to_log, filter) { \
  update_current_stack_frame_line_number(__LINE__); \
  if (the_logger.member(filter)) { \
    istring temp_log = to_log; \
    if (temp_log.length()) { \
      temp_log.insert(0, utility::timestamp(true, true)); \
      BASE_INSTANCE_FUNCTION(func); \
      temp_log += " ["; \
      temp_log += function_name; \
      temp_log += "]"; \
    } \
    the_logger.log(temp_log, filter); \
    update_current_stack_frame_line_number(__LINE__); \
  } \
}
#define INSTANCE_EMERGENCY_LOG(the_logger, to_log) \
  INSTANCE_FILTER_LOG(the_logger, to_log, log_base::ALWAYS_PRINT)

#endif

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