src/support/DebugStream.h

   1 // -*- C++ -*-
   2
   3 // Created by Lars Gullik Bjønnes
   4 // Copyright 1999 Lars Gullik Bjønnes (larsbj@lyx.org)
   5 // Released under the Gnu General Public License
   6
   7 // Implemented and tested on g++ 2.7.2.3
   8
   9 // Primarily developed for use in the LyX Project http://www.lyx.org/
  10 // but should be adaptable to any project.
  11
  12 #ifndef DEBUGSTREAM_H
  13 #define DEBUGSTREAM_H
  14
  15 #include "LOstream.h"
  16
  17 #ifdef TEST_DEBUGSTREAM
  18 #include <string>
  19 struct Debug {
  20         ///
  21         enum type {
  22                 ///
  23                 NONE = 0,
  24                 ///
  25                 INFO       = (1 << 0),   // 1
  26                 ///
  27                 WARN       = (1 << 1),   // 2
  28                 ///
  29                 CRIT       = (1 << 2)   // 4
  30         };
  31         ///
  32         static const type ANY = type(INFO | WARN | CRIT);
  33
  34         /** A function to convert symbolic string names on debug levels
  35             to their numerical value.
  36         */
  37         static Debug::type value(std::string const & val) {
  38                 if (val == "NONE") return Debug::NONE;
  39                 if (val == "INFO") return Debug::INFO;
  40                 if (val == "WARN") return Debug::WARN;
  41                 if (val == "CRIT") return Debug::CRIT;
  42                 return Debug::NONE;
  43         }
  44
  45 };
  46 #endif
  47
  48 /** DebugStream is a ostream intended for debug output. It has also support
  49     for a logfile. Debug output is output to cerr and if the logfile is set,
  50     to the logfile.
  51
  52     Example of Usage:
  53     DebugStream debug;
  54     debug.level(Debug::INFO);
  55     debug.debug(Debug::WARN) << "WARN\n";
  56     debug[Debug::INFO] << "INFO\n";
  57     debug << "Always\n";
  58
  59     Will output:
  60     INFO
  61     Always
  62
  63     If you want to have debug output from time critical code you should
  64     use this construct:
  65     if (debug.debugging(Debug::INFO)) {
  66          debug << "...debug output...\n";
  67     }
  68
  69     To give debug info even if no debug (NONE) is requested:
  70     debug << "... always output ...\n";
  71
  72     To give debug output regardless of what debug level is set (!NONE):
  73     debug.debug() << "...on debug output...\n";
  74     debug[Debug::ANY] << "...on debug output...\n";
  75
  76     To give debug output when a specific debug level is set (INFO):
  77     debug.debug(Debug::INFO) << "...info...\n";
  78     debug[Debug::INFO] << "...info...\n";
  79
  80     To give debug output when either on of debug levels is set (INFO or CRIT):
  81     debug.debug(Debug::type(Debug::INFO | Debug::CRIT)) << "...info/crit...\n";
  82     debug[Debug::type(Debug::INFO | Debug::CRIT)] << "...info/crit...\n";
  83
  84 */
  85 class DebugStream : public ostream {
  86 public:
  87         /// Constructor, sets the debug level to t.
  88         DebugStream(Debug::type t = Debug::NONE);
  89
  90         /// Constructor, sets the log file to f, and the debug level to t.
  91         DebugStream(char const * f, Debug::type t = Debug::NONE);
  92
  93         ///
  94         virtual ~DebugStream();
  95
  96         /// Sets the debug level to t.
  97         void level(Debug::type t) {
  98                 dt = Debug::type(t & Debug::ANY);
  99         }
 100
 101         /// Returns the current debug level.
 102         Debug::type level() const {
 103                 return dt;
 104         }
 105
 106         /// Adds t to the current debug level.
 107         void addLevel(Debug::type t) {
 108                 dt = Debug::type(dt | t);
 109         }
 110
 111         /// Deletes t from the current debug level.
 112         void delLevel(Debug::type t) {
 113                 dt = Debug::type(dt & ~t);
 114         }
 115
 116         /// Sets the debugstreams' logfile to f.
 117         void logFile(char const * f);
 118
 119         /// Returns true if t is part of the current debug level.
 120         bool debugging(Debug::type t = Debug::ANY) const
 121         {
 122                 if (dt & t) return true;
 123                 return false;
 124         }
 125
 126
 127         /** Returns the no-op stream if t is not part of the
 128             current debug level otherwise the real debug stream
 129             is used.
 130         */
 131         ostream & debug(Debug::type t = Debug::ANY) {
 132                 if (dt & t) return *this;
 133                 return nullstream;
 134         }
 135
 136
 137         /** This is an operator to give a more convenient use:
 138             dbgstream[Debug::INFO] << "Info!\n";
 139         */
 140         ostream & operator[](Debug::type t) {
 141                 return debug(t);
 142         }
 143 private:
 144         /// The current debug level
 145         Debug::type dt;
 146         /// The no-op stream.
 147         ostream nullstream;
 148         struct debugstream_internal;
 149         debugstream_internal * internal;
 150 };
 151
 152 #endif