MLogFileWriter Class Reference

Log file writer, one that writes information to a file. More...

Inheritance diagram for MLogFileWriter:

Public Member Functions
	MLogFileWriter ()
	Constructor that creates an uninitialized log file object.
	MLogFileWriter (const MStdString &fileName, unsigned maxFileSizeKB=0)
	Constructor that creates a writable log file with the given file name. More...
virtual	~MLogFileWriter ()
	Object destructor, close the log file.
unsigned	GetMaxFileSizeKB () const
	Get the maximum file size in kilobytes, or zero if the maximum file size is not set. More...
void	SetMaxFileSizeKB (unsigned size)
	Set the maximum file size in kilobytes, or zero if the maximum file size shall not be watched. More...
void	Open (const MStdString &fileName, unsigned maxFileSizeKB=0)
	Open the file for writing, or create a new one with the given name. More...
virtual void	Close ()
	Close the file, if it was open.
void	Clear ()
	Clear the contents of the file, if open, and start the log over from the beginning of the file. More...
void	WriteMessage (const char *data, size_t dataSize)
	Write the whole message to the log file.
void	WriteMessage (const MLogFile::PacketHeader &header, const char *data)
	Send the message with the prepared header. More...
void	WriteMessage (unsigned code, const char *message, unsigned length)
	Send the message with the specified code. More...
void	WriteMultipleMessages (const MByteString &messages)
	Send several messages formatted as a buffer containing packets. More...
Public Member Functions inherited from MLogFile
virtual	~MLogFile ()
	Object destructor, close the log file.
bool	IsOpen () const
	Tells if the file is open. More...
const MStdString &	GetFileName () const
	Get the file name, as set for logging. More...
const MStdString &	GetOpenWarnings () const
	Get the warning message which might arise during opening a file and checking its contents. More...
void	SetListener (MMonitorFile *listener)
	Sets the listener object to start handling events. More...
bool	GetObfuscate () const
void	SetObfuscate (bool yes)

Additional Inherited Members
Public Types inherited from MLogFile
enum	{   PAGE_HEADER_SIGNATURE = 0xA2EBBAED,   PAGE_OBFUSCATED_HEADER_SIGNATURE = 0xA2EBBAEC,   PAGE_TOTAL_SIZE = 0x1000,   PAGE_HEADER_SIZE = 16,   PAGE_FOOTER_SIZE = 4,   PAGE_BODY_SIZE = PAGE_TOTAL_SIZE - PAGE_HEADER_SIZE - PAGE_FOOTER_SIZE,   PACKET_HEADER_SIZE = 10,   NUMBER_OF_PAGES_LIMIT = 0xFFFF }
Protected Member Functions inherited from MLogFile
	MLogFile ()
	Constructor that creates an uninitialized log file object.

Detailed Description

Log file writer, one that writes information to a file.

It can be used separately from MMonitorFile to read and produce the log with the possible circular buffer behavior.

Constructor & Destructor Documentation

MLogFileWriter::MLogFileWriter ( const MStdString &  fileName, unsigned  maxFileSizeKB = 0  )

inlineexplicit

Constructor that creates a writable log file with the given file name.

The value of maxFileSizeKB is taken into account to possibly limit the file size.

Precondition

File, if given, shall be a valid file name, or an exception is thrown. Write access to a file is attempted. If anything fails there is an exception.

Member Function Documentation

void MLogFileWriter::Clear

(

)

Clear the contents of the file, if open, and start the log over from the beginning of the file.

It is not an error to clear the file which is not open.

Precondition

The file, if open, has to be open for writing, and the necessary write operations shall be successful, or the error is thrown.

unsigned MLogFileWriter::GetMaxFileSizeKB ( ) const

inline

Get the maximum file size in kilobytes, or zero if the maximum file size is not set.

Zero, there is no imposed restriction on the file size, is the default. Once the maximum size is achieved, the old data will start to disappear from the file as new data is added.

void MLogFileWriter::Open	(	const MStdString &	fileName,
		unsigned	maxFileSizeKB = 0
	)

Open the file for writing, or create a new one with the given name.

The value of maxFileSizeKB is taken into account to possibly limit the file size.

Precondition

File, if given, shall be a valid file name, the open procedure has to be achievable by the operating system, or an exception is thrown.

void MLogFileWriter::SetMaxFileSizeKB

(

unsigned

size

)

Set the maximum file size in kilobytes, or zero if the maximum file size shall not be watched.

Zero, there is no imposed restriction on the file size, is the default. Once the maximum size is achieved, the old data will start to disappear from the file as new data is added.

If a file exists prior the call, but its size is bigger than the imposing restriction, the file will be truncated (which can possibly take a significant amount of time).

Precondition

The size shall either be zero, no size restriction, or it shall be in range 16 to approximately 32,000 kilobytes (which corresponds to 32 megabytes), or a range expression takes place.

void MLogFileWriter::WriteMessage	(	const MLogFile::PacketHeader &	header,
		const char *	data
	)

Send the message with the prepared header.

Precondition

Header shall be valid, length corresponds to the given data pointer. Also, any file write-related exception can be thrown.

void MLogFileWriter::WriteMessage	(	unsigned	code,
		const char *	message,
		unsigned	length
	)

Send the message with the specified code.

Precondition

Code is valid and message has a valid format. The check is done in the debugging version that the code fits in range 0 to 0xFFFF. Also, any file write-related exception can be thrown.

void MLogFileWriter::WriteMultipleMessages

(

const MByteString &

messages

)

Send several messages formatted as a buffer containing packets.

Precondition

Messages have a valid format, no part of a message can be written with this service, only a number of complete messages. There is a debug check for a format error. Also, any file write-related exception can be thrown.