src/util/Log.h

   1 #ifndef REMOTE_UTIL_LOG_H
   2 #define REMOTE_UTIL_LOG_H
   3
   4 #include "remote.h"
   5
   6 namespace remote { namespace util {
   7
   8 class Log {
   9         public:
  10                 /** Log level specifiers
  11                  *
  12                  * The following log levels can be used to specify the default
  13                  * log level when opening a log. They are listed in the order
  14                  * of priority starting with the most important. When
  15                  * specifying the log level, messages with higher priorities
  16                  * are automatically included, e.g. Log::INFO will include
  17                  * Log::ERROR and Log::FATAL.
  18                  *
  19                  * The specifiers all maps internally to syslog priorities as
  20                  * defined in <syslog.h>.
  21                  */
  22                 enum {
  23                         FATAL = LOG_EMERG,
  24                         ERROR = LOG_ERR,
  25                         WARN  = LOG_WARNING,
  26                         INFO  = LOG_INFO,
  27                         DEBUG = LOG_DEBUG,
  28                 };
  29
  30                 /** Syslog specifier
  31                  *
  32                  * May be passed when opening a log, to specify that
  33                  * syslog should be used. E.g.:
  34                  *
  35                  *      Log::open("remote-mch", Log::INFO, Log::SYSLOG);
  36                  */
  37                 static const FILE *SYSLOG;
  38
  39                 /** Setup logging
  40                  *
  41                  * Configures the various logging options and prepares
  42                  * for future calls to redirect messages to the
  43                  * requested place.
  44                  *
  45                  * The log file is an ordinary file handle. It should be
  46                  * a file opened in append mode. To use syslog, pass NULL.
  47                  * The default is to use stdout.
  48                  *
  49                  * @param ident         A unique log identifier
  50                  * @param level         The default log level, messages
  51                  *                      with log level of lower importance
  52                  *                      than this will be discarded.
  53                  * @param file          The log file handle.
  54                  */
  55                 static void open(const char *ident, int level = Log::INFO,
  56                                  const FILE *file = stdout);
  57
  58                 /** Fatal error message
  59                  *
  60                  * An emergency condition occurred rendering the system
  61                  * unusable.
  62                  */
  63                 static void fatal(const char *format, ...);
  64
  65                 /** Error message
  66                  *
  67                  * An error condition occurred.
  68                  */
  69                 static void error(const char *format, ...);
  70
  71                 /** Warning message
  72                  *
  73                  * An warning condition occurred.
  74                  */
  75                 static void warn(const char *format, ...);
  76
  77                 /** Informational message
  78                  *
  79                  * A normal and non-significant condition occurred.
  80                  */
  81                 static void info(const char *format, ...);
  82
  83                 /** Debug message
  84                  *
  85                  * For logging occurrences relevant during debuging.
  86                  */
  87                 static void debug(const char *format, ...);
  88
  89         private:
  90                 static void put(int priority, const char *format, va_list params);
  91                 static const char *ident;
  92                 static const FILE *file;
  93                 static int level;
  94
  95                 static inline bool use_syslog()
  96                 {
  97                         return Log::file == SYSLOG;
  98                 }
  99
 100                 /* This might be a bad hardcoded way to discard messages of
 101                  * less importance. However, the BSD syslog.h file used by
 102                  * glibc states that EMERG < ERR < WARNING < INFO < DEBUG. */
 103                 static inline bool ignore(int priority)
 104                 {
 105                         return priority > Log::level;
 106                 }
 107 };
 108
 109 }}
 110
 111 #endif