ErrorVeneer Class Reference

Base class for ErrorHandlers that forward messages. More...

#include <error.hh>

Inheritance diagram for ErrorVeneer:

Public Member Functions
	ErrorVeneer (ErrorHandler *errh)
	Construct an ErrorVeneer.
String	vformat (const char *fmt, va_list val)
	Format an error string.
String	decorate (const String &str)
	Decorate an error message.
void *	emit (const String &str, void *user_data, bool more)
	Output an error message line.
void	account (int level)
	Account for an error message at level level.
Public Member Functions inherited from ErrorHandler
	ErrorHandler ()
	Construct an ErrorHandler.
void	debug (const char *fmt,...)
	Print a debug message (level el_debug).
void	message (const char *fmt,...)
	Print an informational message (level el_info).
int	warning (const char *fmt,...)
	Print a warning message (level el_warning).
int	error (const char *fmt,...)
	Print an error message (level el_error).
int	fatal (const char *fmt,...)
	Print a fatal error message (level el_fatal).
void	ldebug (const String &landmark, const char *fmt,...)
	Print a debug message with a landmark annotation.
void	lmessage (const String &landmark, const char *fmt,...)
	Print an informational message with a landmark annotation.
int	lwarning (const String &landmark, const char *fmt,...)
	Print a warning message with a landmark annotation.
int	lerror (const String &landmark, const char *fmt,...)
	Print an error message with a landmark annotation.
int	lfatal (const String &landmark, const char *fmt,...)
	Print a fatal error message with a landmark annotation.
int	xmessage (const String &str)
	Print an annotated error message.
int	xmessage (const String &anno, const String &str)
	Print an error message, adding annotations.
int	xmessage (const String &anno, const char *fmt, va_list val)
	Format and print an error message, adding annotations.
int	xmessage (const String &landmark, const String &anno, const String &str)
	Print an error message, adding landmark and other annotations.
int	xmessage (const String &landmark, const String &anno, const char *fmt, va_list val)
	Format and print an error message, adding landmark and other annotations.
int	nerrors () const
	Return the number of errors reported via this handler.
String	format (const char *fmt,...)
	Format an error string.
virtual void	clear ()
	Clear accumulated error state.

Additional Inherited Members
Public Types inherited from ErrorHandler
enum	Level {   el_abort = -999 , el_fatal = -1 , el_emergency = 0 , el_alert = 1 ,   el_critical = 2 , el_error = 3 , el_warning = 4 , el_notice = 5 ,   el_info = 6 , el_debug = 7 }
	Error level constants. More...
enum	ConversionFlags {   cf_zero_pad = 1 , cf_plus_positive = 2 , cf_space_positive = 4 , cf_left_just = 8 ,   cf_alternate_form = 16 , cf_singlequote = 32 , cf_uppercase = 64 , cf_signed = 128 ,   cf_negative = 256 , cf_utf8 = 1024 }
typedef String(*	ConversionFunction) (int flags, VA_LIST_REF_T)
Static Public Member Functions inherited from ErrorHandler
static ErrorHandler *	static_initialize (ErrorHandler *errh)
	Initialize the ErrorHandler implementation.
static void	static_cleanup ()
	Tear down the ErrorHandler implementation.
static ErrorHandler *	default_handler ()
	Return the default ErrorHandler.
static void	set_default_handler (ErrorHandler *errh)
	Set the default ErrorHandler to errh.
static ErrorHandler *	silent_handler ()
	Return the global silent ErrorHandler.
static String	xformat (int default_flags, const char *fmt,...)
	Format an error string.
static String	vxformat (int default_flags, const char *fmt, va_list val)
static String	xformat (const char *fmt,...)
static String	vxformat (const char *fmt, va_list val)
static String	make_anno (const char *name, const String &value)
	Create an error annotation.
static String	combine_anno (const String &str, const String &anno)
	Apply annotations from anno to every line in str.
static const char *	parse_anno (const String &str, const char *begin, const char *end,...) ERRH_SENTINEL
	Parse error annotations from a string.
static const char *	skip_anno (const char *begin, const char *end)
	Skip a string's error annotations.
static String	make_landmark_anno (const String &x)
	Return a landmark annotation equal to x.
static String	clean_landmark (const String &landmark, bool colon=false)
	Clean the landmark.
static Conversion *	add_conversion (const String &name, ConversionFunction func)
static int	remove_conversion (Conversion *conversion)
Static Public Attributes inherited from ErrorHandler
static const char	e_abort [] = "<-999>"
	Error level indicators.
static const char	e_fatal [] = "<-1>"
static const char	e_emergency [] = "<0>"
static const char	e_alert [] = "<1>"
static const char	e_critical [] = "<2>"
static const char	e_error [] = "<3>"
static const char	e_warning [] = "<4>"
static const char	e_warning_annotated [] = "<4>warning: "
static const char	e_notice [] = "<5>"
static const char	e_info [] = "<6>"
static const char	e_debug [] = "<7>"
static const int	ok_result = 0
static const int	error_result = -EINVAL

Detailed Description

Base class for ErrorHandlers that forward messages.

ErrorHandlers can stack. Stacking ErrorHandlers simplify modify a message and then pass the result to a base ErrorHandler, which does the actual printing. The ErrorVeneer base class simplifies the implementation of stacking ErrorHandlers. It provides versions of ErrorHandler's format(), decorate(), emit(), and account() methods that forward to the underlying handler. Note that the clear() method is not automatically forwarded.

Constructor & Destructor Documentation

ErrorVeneer()

ErrorVeneer::ErrorVeneer ( ErrorHandler *  errh )

inline

Construct an ErrorVeneer.

Parameters

errh	base ErrorHandler

If errh is 0, then the ErrorVeneer acts like a SilentErrorHandler.

Member Function Documentation

vformat()

String ErrorVeneer::vformat ( const char *  fmt, va_list  val  )

virtual

Format an error string.

Parameters

fmt	format string
val	argument list

Warning

ErrorHandler users don't need to call this function directly; it is called implicitly by the error()/xmessage() functions.

This virtual function is called to format an error message. The default implementation returns the result of vxformat(fmt, val).

Reimplemented from ErrorHandler.

decorate()

String ErrorVeneer::decorate ( const String &  str )

virtual

Decorate an error message.

Parameters

str	error message, possibly with annotations

Returns

decorated error message

Warning

ErrorHandler users don't need to call this function directly; it is called implicitly by the error()/xmessage() functions.

This virtual function is called to decorate an error message before it is emitted. The input str is an error message string, possibly annotated. The default implementation returns str unchanged. Other ErrorHandlers might add context lines (ContextErrorHandler), prefixes (PrefixErrorHandler), or a default landmark (LandmarkErrorHandler).

Reimplemented from ErrorHandler.

Reimplemented in PrefixErrorHandler, and LandmarkErrorHandler.

emit()

void * ErrorVeneer::emit ( const String &  str, void *  user_data, bool  more  )

virtual

Output an error message line.

Parameters

str	error message line, possibly with annotations
user_data	callback data, 0 for first line in a message
more	true iff this is the last line in the current message

Returns

user_data to be passed to emit() for the next line

Warning

ErrorHandler users don't need to call this function directly; it is called implicitly by the error()/xmessage() functions.

After calling decorate(), ErrorHandler splits the message into individual lines and calls emit() once per line. ErrorHandler subclasses should output the error lines as appropriate; for example, FileErrorHandler outputs the error message to a file.

str does not contain a newline, but may contain annotations, including a landmark annotation. Most ErrorHandlers use parse_anno() to extract the landmark annotation, clean it with clean_landmark(), and print it ahead of the error message proper.

ErrorHandler can handle multi-line error messages. However, the emit() function takes a line at a time; this is more useful in practice for most error message printers. The user_data and more arguments can help an ErrorHandler combine the lines of a multi-line error message. user_data is null for the first line; for second and subsequent lines, ErrorHandler passes the result of the last line's emit() call. more is true iff this is the last line in the current message.

The default emit() implementation does nothing.

Reimplemented from ErrorHandler.

account()

void ErrorVeneer::account ( int  level )

virtual

Account for an error message at level level.

Parameters

level

minimum error level in the message

Warning

ErrorHandler users don't need to call this function directly; it is called implicitly by the error()/xmessage() functions.

After calling emit() for the lines of an error message, ErrorHandler calls account(), passing the minimum (worst) error level of any message line (or 1000 if no line had a level). The default implementation updates the nerrors() counter. Some other ErrorHandlers add account() behavior that, for example, exits after printing messages at el_fatal level or below.

Reimplemented from ErrorHandler.

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The documentation for this class was generated from the following files:

• include/click/error.hh
• lib/error.cc