A simple implementation of a Logger that writes to a file. More...

Inheritance diagram for FileLogger:

Public Member Functions

 FileLogger (const File &fileToWriteTo, const String &welcomeMessage, const int64 maxInitialFileSizeBytes=128 *1024)
 Creates a FileLogger for a given file. More...
 
 ~FileLogger ()
 Destructor. More...
 
const FilegetLogFile () const noexcept
 Returns the file that this logger is writing to. More...
 
void logMessage (const String &)
 This is overloaded by subclasses to implement custom logging behaviour. More...
 
- Public Member Functions inherited from Logger
virtual ~Logger ()
 Destructor. More...
 

Static Public Member Functions

static FileLoggercreateDefaultAppLogger (const String &logFileSubDirectoryName, const String &logFileName, const String &welcomeMessage, const int64 maxInitialFileSizeBytes=128 *1024)
 Helper function to create a log file in the correct place for this platform. More...
 
static FileLoggercreateDateStampedLogger (const String &logFileSubDirectoryName, const String &logFileNameRoot, const String &logFileNameSuffix, const String &welcomeMessage)
 Helper function to create a log file in the correct place for this platform. More...
 
static File getSystemLogFileFolder ()
 Returns an OS-specific folder where log-files should be stored. More...
 
static void trimFileSize (const File &file, int64 maxFileSize)
 This is a utility function which removes lines from the start of a text file to make sure that its total size is below the given size. More...
 
- Static Public Member Functions inherited from Logger
static void JUCE_CALLTYPE setCurrentLogger (Logger *newLogger) noexcept
 Sets the current logging class to use. More...
 
static Logger *JUCE_CALLTYPE getCurrentLogger () noexcept
 Returns the current logger, or nullptr if no custom logger has been set. More...
 
static void JUCE_CALLTYPE writeToLog (const String &message)
 Writes a string to the current logger. More...
 
static void JUCE_CALLTYPE outputDebugString (const String &text)
 Writes a message to the standard error stream. More...
 

Additional Inherited Members

- Protected Member Functions inherited from Logger
 Logger ()
 

Detailed Description

A simple implementation of a Logger that writes to a file.

See also
Logger

Constructor & Destructor Documentation

◆ FileLogger()

FileLogger::FileLogger ( const File fileToWriteTo,
const String welcomeMessage,
const int64  maxInitialFileSizeBytes = 128 *1024 
)

Creates a FileLogger for a given file.

Parameters
fileToWriteTothe file that to use - new messages will be appended to the file. If the file doesn't exist, it will be created, along with any parent directories that are needed.
welcomeMessagewhen opened, the logger will write a header to the log, along with the current date and time, and this welcome message
maxInitialFileSizeBytesif this is zero or greater, then if the file already exists but is larger than this number of bytes, then the start of the file will be truncated to keep the size down. This prevents a log file getting ridiculously large over time. The file will be truncated at a new-line boundary. If this value is less than zero, no size limit will be imposed; if it's zero, the file will always be deleted. Note that the size is only checked once when this object is created - any logging that is done later will be appended without any checking

◆ ~FileLogger()

FileLogger::~FileLogger ( )

Destructor.

Member Function Documentation

◆ getLogFile()

const File& FileLogger::getLogFile ( ) const
noexcept

Returns the file that this logger is writing to.

References JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR, and Logger::logMessage().

◆ createDefaultAppLogger()

static FileLogger* FileLogger::createDefaultAppLogger ( const String logFileSubDirectoryName,
const String logFileName,
const String welcomeMessage,
const int64  maxInitialFileSizeBytes = 128 *1024 
)
static

Helper function to create a log file in the correct place for this platform.

The method might return nullptr if the file can't be created for some reason.

Parameters
logFileSubDirectoryNamethe name of the subdirectory to create inside the logs folder (as returned by getSystemLogFileFolder). It's best to use something like the name of your application here.
logFileNamethe name of the file to create, e.g. "MyAppLog.txt".
welcomeMessagea message that will be written to the log when it's opened.
maxInitialFileSizeBytes(see the FileLogger constructor for more info on this)

◆ createDateStampedLogger()

static FileLogger* FileLogger::createDateStampedLogger ( const String logFileSubDirectoryName,
const String logFileNameRoot,
const String logFileNameSuffix,
const String welcomeMessage 
)
static

Helper function to create a log file in the correct place for this platform.

The filename used is based on the root and suffix strings provided, along with a time and date string, meaning that a new, empty log file will be always be created rather than appending to an exising one.

The method might return nullptr if the file can't be created for some reason.

Parameters
logFileSubDirectoryNamethe name of the subdirectory to create inside the logs folder (as returned by getSystemLogFileFolder). It's best to use something like the name of your application here.
logFileNameRootthe start of the filename to use, e.g. "MyAppLog_". This will have a timestamp and the logFileNameSuffix appended to it
logFileNameSuffixthe file suffix to use, e.g. ".txt"
welcomeMessagea message that will be written to the log when it's opened.

◆ getSystemLogFileFolder()

static File FileLogger::getSystemLogFileFolder ( )
static

Returns an OS-specific folder where log-files should be stored.

On Windows this will return a logger with a path such as: c:\Documents and Settings\username\Application Data\[logFileSubDirectoryName]\[logFileName]

On the Mac it'll create something like: ~/Library/Logs/[logFileSubDirectoryName]/[logFileName]

See also
createDefaultAppLogger

◆ logMessage()

void FileLogger::logMessage ( const String message)
virtual

This is overloaded by subclasses to implement custom logging behaviour.

See also
setCurrentLogger

Implements Logger.

◆ trimFileSize()

static void FileLogger::trimFileSize ( const File file,
int64  maxFileSize 
)
static

This is a utility function which removes lines from the start of a text file to make sure that its total size is below the given size.


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