Logging

Logging support. More...

Collaboration diagram for Logging:

Classes
class	Logger
	Base logger class. More...
class	Log
	Wraps a set of static functions for easy global logging access. More...
class	StdoutLogger
	Simple logger that writes to stdout. More...
class	FileLogger
	Simple logger that writes to a file. More...

Usage Information

Logging support.

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Class Documentation

class Logger

Base logger class.

There are two types of logging levels that are used by this class. First there is the filter level. Any log message that is assigned a level higher than the current filter level is discarded. Secondly there is the current output level. Log messages that do not have their own level use the current output level to determine if they should be shown or not.

The two methods setFilterLevel() and setOutputLevel() set the filter and default output logging levels, respectively. There are corresponding getter methods as well. Both the filter and output levels are initialized to INFO during object construction.

Most use of the logger classes is expected to be through the Log class. It provides static logging methods that call through to a global singleton logger instance. There is also a Log::SetOutputLevel utility class that makes it extremely easiy to temporarily change the default output logging level.

Of all the overloaded log() methods in this class, none of them are really expected to be reimplemented by subclasses. Instead, there is the single protected _log() method that takes a simple string pointer. The other log methods all wind up calling _log(), so it provides a single point to override. In fact, _log() is pure virtual, so subclasses must implement it.

See also

Log

There are two types of logging levels that are used by this class. First there is the filter level. Any log message that is assigned a level higher than the current filter level is discarded. Secondly there is the current output level. Log messages that do not have their own level use the current output level to determine if they should be shown or not.

The two methods setFilterLevel() and setOutputLevel() set the filter and default output logging levels, respectively. There are corresponding getter methods as well. Both the filter and output levels are initialized to kInfo during object construction.

Most use of the logger classes is expected to be through the Log class. It provides static logging methods that call through to a global singleton logger instance. There is also a Log::SetOutputLevel utility class that makes it extremely easiy to temporarily change the default output logging level.

Of all the overloaded log() methods in this class, none of them are really expected to be reimplemented by subclasses. Instead, there is the single protected _log() method that takes a simple string pointer. The other log methods all wind up calling _log(), so it provides a single point to override. In fact, _log() is pure virtual, so subclasses must implement it.

See also

Log

Inheritance diagram for Logger:

Public Types
enum	log_level_t {   URGENT = 0,   ERROR,   WARNING,   INFO,   INFO2,   DEBUG,   DEBUG2,   kUrgent = 0,   kJson,   kError,   kWarning,   kInfo,   kInfo2,   kDebug,   kDebug2,   kInfo1 = kInfo,   kDebug1 = kDebug }
	Logging levels. More...
enum	log_level_t {   URGENT = 0,   ERROR,   WARNING,   INFO,   INFO2,   DEBUG,   DEBUG2,   kUrgent = 0,   kJson,   kError,   kWarning,   kInfo,   kInfo2,   kDebug,   kDebug2,   kInfo1 = kInfo,   kDebug1 = kDebug }
	Logging levels. More...
Public Member Functions
	Logger ()
	Default constructor.
virtual	~Logger ()
	Destructor.
	Logger ()
	Default constructor.
virtual	~Logger ()
	Destructor.
Logging levels
void	setFilterLevel (log_level_t level)
	Changes the logging level to level.
log_level_t	getFilterLevel () const
	Returns the current logging filter level.
void	setOutputLevel (log_level_t level)
	Changes the logging output level to level.
log_level_t	getOutputLevel () const
	Returns the current logging output level.
void	setFilterLevel (log_level_t level)
	Changes the logging level to level.
log_level_t	getFilterLevel () const
	Returns the current logging filter level.
void	setOutputLevel (log_level_t level)
	Changes the logging output level to level.
log_level_t	getOutputLevel () const
	Returns the current logging output level.
Logging
virtual void	log (const char *fmt,...)
	Log with format.
virtual void	log (const std::string &msg)
	Log a string object.
virtual void	log (log_level_t level, const char *fmt,...)
	Log with format at a specific output level.
virtual void	log (log_level_t level, const std::string &msg)
	Log a string output at a specific output level.
virtual void	log (const char *fmt, va_list args)
	Log with format using an argument list.
virtual void	log (log_level_t level, const char *fmt, va_list args)
	Log with format using an argument with a specific output level. More...
virtual void	log (const char *fmt,...)
	Log with format.
virtual void	log (const std::string &msg)
	Log a string object.
virtual void	log (log_level_t level, const char *fmt,...)
	Log with format at a specific output level.
virtual void	log (log_level_t level, const std::string &msg)
	Log a string output at a specific output level.
virtual void	log (const char *fmt, va_list args)
	Log with format using an argument list.
virtual void	log (log_level_t level, const char *fmt, va_list args)
	Log with format using an argument with a specific output level.
Protected Member Functions
virtual void	_log (const char *msg)=0
	The base pure virtual logging function implemented by subclasses.
virtual void	_log (const char *msg)=0
	The base pure virtual logging function implemented by subclasses.
Protected Attributes
log_level_t	m_filter
	The current logging filter level.
log_level_t	m_level
	The current log output level.

Member Enumeration Documentation

enum Logger::log_level_t

Logging levels.

Enumerator
URGENT	The lowest level, for messages that must always be logged.
ERROR	For fatal error messages.
WARNING	For non-fatal warning messages.
INFO	The normal log level, for status messages.
INFO2	For verbose status messages.
DEBUG	For internal reporting.
DEBUG2	Highest log level; verbose debug logging.
kUrgent	The lowest level, for messages that must always be logged.
kJson	For machine language output only.
kError	For fatal error messages.
kWarning	For non-fatal warning messages.
kInfo	The normal log level, for status messages.
kInfo2	For verbose status messages.
kDebug	For internal reporting.
kDebug2	Highest log level; verbose debug logging.
kInfo1	Alias for kInfo.
kDebug1	Alias for kDebug.

enum Logger::log_level_t

Logging levels.

Enumerator
URGENT	The lowest level, for messages that must always be logged.
ERROR	For fatal error messages.
WARNING	For non-fatal warning messages.
INFO	The normal log level, for status messages.
INFO2	For verbose status messages.
DEBUG	For internal reporting.
DEBUG2	Highest log level; verbose debug logging.
kUrgent	The lowest level, for messages that must always be logged.
kJson	For machine language output only.
kError	For fatal error messages.
kWarning	For non-fatal warning messages.
kInfo	The normal log level, for status messages.
kInfo2	For verbose status messages.
kDebug	For internal reporting.
kDebug2	Highest log level; verbose debug logging.
kInfo1	Alias for kInfo.
kDebug1	Alias for kDebug.

Member Function Documentation

void Logger::log ( log_level_t  level, const char *  fmt, va_list  args  )

virtual

Log with format using an argument with a specific output level.

Allocates a temporary 1KB buffer which is used to hold the formatted string.

class Log

Wraps a set of static functions for easy global logging access.

This class has a set of static methods that make it easy to access a global logger instance without having to worry about extern symbols. It does this by keeping a static member variable pointing at the singleton logger instance, which is set with the setLogger() static method.

There is also an inner utility class called SetOutputLevel that uses C++ scoping rules to temporarily change the output logging level. When the SetOutputLevel instance falls out of scope the output level is restored to the previous value.

Collaboration diagram for Log:

Static Public Member Functions
Singleton logger access
static Logger *	getLogger ()
	Returns the current global logger singleton.
static void	setLogger (Logger *logger)
	Sets the global logger singleton instance.
static Logger *	getLogger ()
	Returns the current global logger singleton.
static void	setLogger (Logger *logger)
	Sets the global logger singleton instance.
Logging
static void	log (const char *fmt,...)
	Log with format.
static void	log (const std::string &msg)
	Log a string object.
static void	log (Logger::log_level_t level, const char *fmt,...)
	Log with format at a specific output level.
static void	log (Logger::log_level_t level, const std::string &msg)
	Log a string output at a specific output level.
static void	log (const char *fmt,...)
	Log with format.
static void	log (const std::string &msg)
	Log a string object.
static void	log (Logger::log_level_t level, const char *fmt,...)
	Log with format at a specific output level.
static void	log (Logger::log_level_t level, const std::string &msg)
	Log a string output at a specific output level.
Logging level helpers
These static methods log a message with an implicit log level.
static void	urgent (const char *fmt,...)
	Log a message with Logger::kUrgent level.
static void	json (const char *fmt,...)
	Log a message with Logger::kJson level.
static void	error (const char *fmt,...)
	Log a message with Logger::kError level.
static void	warning (const char *fmt,...)
	Log a message with Logger::kWarning level.
static void	info (const char *fmt,...)
	Log a message with Logger::kInfo level.
static void	info2 (const char *fmt,...)
	Log a message with Logger::kInfo2 level.
static void	debug (const char *fmt,...)
	Log a message with Logger::kDebug level.
static void	debug2 (const char *fmt,...)
	Log a message with Logger::kDebug2 level.
Static Protected Attributes
static Logger *	s_logger = NULL
	The single global logger instance.

class StdoutLogger

Simple logger that writes to stdout.

Inheritance diagram for StdoutLogger:

Collaboration diagram for StdoutLogger:

Protected Member Functions
virtual void	_log (const char *msg)
	Logs the message to stdout.
virtual void	_log (const char *msg)
	Logs the message to stdout.

Additional Inherited Members
Public Types inherited from Logger
enum	log_level_t {   URGENT = 0,   ERROR,   WARNING,   INFO,   INFO2,   DEBUG,   DEBUG2,   kUrgent = 0,   kJson,   kError,   kWarning,   kInfo,   kInfo2,   kDebug,   kDebug2,   kInfo1 = kInfo,   kDebug1 = kDebug }
	Logging levels. More...
enum	log_level_t {   URGENT = 0,   ERROR,   WARNING,   INFO,   INFO2,   DEBUG,   DEBUG2,   kUrgent = 0,   kJson,   kError,   kWarning,   kInfo,   kInfo2,   kDebug,   kDebug2,   kInfo1 = kInfo,   kDebug1 = kDebug }
	Logging levels. More...
Public Member Functions inherited from Logger
	Logger ()
	Default constructor.
virtual	~Logger ()
	Destructor.
	Logger ()
	Default constructor.
virtual	~Logger ()
	Destructor.
void	setFilterLevel (log_level_t level)
	Changes the logging level to level.
log_level_t	getFilterLevel () const
	Returns the current logging filter level.
void	setOutputLevel (log_level_t level)
	Changes the logging output level to level.
log_level_t	getOutputLevel () const
	Returns the current logging output level.
void	setFilterLevel (log_level_t level)
	Changes the logging level to level.
log_level_t	getFilterLevel () const
	Returns the current logging filter level.
void	setOutputLevel (log_level_t level)
	Changes the logging output level to level.
log_level_t	getOutputLevel () const
	Returns the current logging output level.
virtual void	log (const char *fmt,...)
	Log with format.
virtual void	log (const std::string &msg)
	Log a string object.
virtual void	log (log_level_t level, const char *fmt,...)
	Log with format at a specific output level.
virtual void	log (log_level_t level, const std::string &msg)
	Log a string output at a specific output level.
virtual void	log (const char *fmt, va_list args)
	Log with format using an argument list.
virtual void	log (log_level_t level, const char *fmt, va_list args)
	Log with format using an argument with a specific output level. More...
virtual void	log (const char *fmt,...)
	Log with format.
virtual void	log (const std::string &msg)
	Log a string object.
virtual void	log (log_level_t level, const char *fmt,...)
	Log with format at a specific output level.
virtual void	log (log_level_t level, const std::string &msg)
	Log a string output at a specific output level.
virtual void	log (const char *fmt, va_list args)
	Log with format using an argument list.
virtual void	log (log_level_t level, const char *fmt, va_list args)
	Log with format using an argument with a specific output level.
Protected Attributes inherited from Logger
log_level_t	m_filter
	The current logging filter level.
log_level_t	m_level
	The current log output level.

class FileLogger

Simple logger that writes to a file.

Inheritance diagram for FileLogger:

Collaboration diagram for FileLogger:

Public Member Functions
	FileLogger (const char *file_path)
Public Member Functions inherited from Logger
	Logger ()
	Default constructor.
virtual	~Logger ()
	Destructor.
	Logger ()
	Default constructor.
virtual	~Logger ()
	Destructor.
void	setFilterLevel (log_level_t level)
	Changes the logging level to level.
log_level_t	getFilterLevel () const
	Returns the current logging filter level.
void	setOutputLevel (log_level_t level)
	Changes the logging output level to level.
log_level_t	getOutputLevel () const
	Returns the current logging output level.
void	setFilterLevel (log_level_t level)
	Changes the logging level to level.
log_level_t	getFilterLevel () const
	Returns the current logging filter level.
void	setOutputLevel (log_level_t level)
	Changes the logging output level to level.
log_level_t	getOutputLevel () const
	Returns the current logging output level.
virtual void	log (const char *fmt,...)
	Log with format.
virtual void	log (const std::string &msg)
	Log a string object.
virtual void	log (log_level_t level, const char *fmt,...)
	Log with format at a specific output level.
virtual void	log (log_level_t level, const std::string &msg)
	Log a string output at a specific output level.
virtual void	log (const char *fmt, va_list args)
	Log with format using an argument list.
virtual void	log (log_level_t level, const char *fmt, va_list args)
	Log with format using an argument with a specific output level. More...
virtual void	log (const char *fmt,...)
	Log with format.
virtual void	log (const std::string &msg)
	Log a string object.
virtual void	log (log_level_t level, const char *fmt,...)
	Log with format at a specific output level.
virtual void	log (log_level_t level, const std::string &msg)
	Log a string output at a specific output level.
virtual void	log (const char *fmt, va_list args)
	Log with format using an argument list.
virtual void	log (log_level_t level, const char *fmt, va_list args)
	Log with format using an argument with a specific output level.
Protected Member Functions
virtual void	_log (const char *msg)
	Logs the message to the file.
Protected Attributes
const std::string	m_file_path
	The name of the file, including the path, to log to.
std::ofstream	m_logFile
	The name of the file, including the path, to log to.
Protected Attributes inherited from Logger
log_level_t	m_filter
	The current logging filter level.
log_level_t	m_level
	The current log output level.

Additional Inherited Members
Public Types inherited from Logger
enum	log_level_t {   URGENT = 0,   ERROR,   WARNING,   INFO,   INFO2,   DEBUG,   DEBUG2,   kUrgent = 0,   kJson,   kError,   kWarning,   kInfo,   kInfo2,   kDebug,   kDebug2,   kInfo1 = kInfo,   kDebug1 = kDebug }
	Logging levels. More...
enum	log_level_t {   URGENT = 0,   ERROR,   WARNING,   INFO,   INFO2,   DEBUG,   DEBUG2,   kUrgent = 0,   kJson,   kError,   kWarning,   kInfo,   kInfo2,   kDebug,   kDebug2,   kInfo1 = kInfo,   kDebug1 = kDebug }
	Logging levels. More...