Inheritance diagram for os::File:

Classes
class	Private

Public Types
enum	{ DEFAULT_BUFFER_SIZE =32768 }

Public Member Functions
	File ()
	Default constructor. More...

	File (const String &cPath, int nOpenMode=O_RDONLY)
	Construct a file from a regular path. More...

	File (const Directory &cDir, const String &cName, int nOpenMode=O_RDONLY)
	Open a file addressed as a name inside a specified directory. More...

	File (const FileReference &cRef, int nOpenMode=O_RDONLY)
	Open a file referred to by a os::FileReference. More...

	File (const FSNode &cNode)
	Construct a file from a FSNode. More...

	File (int nFD)
	Construct a file object from a open filedescriptor. More...

	File (const File &cFile)
	Copy constructor. More...

virtual	~File ()

virtual status_t	FDChanged (int nNewFD, const struct stat &sStat)

virtual off_t	GetSize (bool bUpdateCache=true) const

virtual ssize_t	Read (void *pBuffer, ssize_t nSize)

virtual ssize_t	Write (const void *pBuffer, ssize_t nSize)

virtual ssize_t	ReadPos (off_t nPos, void *pBuffer, ssize_t nSize)

virtual ssize_t	WritePos (off_t nPos, const void *pBuffer, ssize_t nSize)

virtual off_t	Seek (off_t nPos, int nMode)
	Move the file pointer. More...

status_t	SetBufferSize (int nSize)
	Set the size of the files caching buffer. More...

int	GetBufferSize () const
	Obtain the files buffer size. More...

status_t	Flush ()
	Write unwritten data to the underlying file. More...

Public Member Functions inherited from os::SeekableIO
virtual	~SeekableIO ()

Public Member Functions inherited from os::StreamableIO
virtual	~StreamableIO ()

Public Member Functions inherited from os::FSNode
	FSNode ()
	Default contructor. More...

	FSNode (const String &cPath, int nOpenMode=O_RDONLY)
	Construct a FSNode from a file path. More...

	FSNode (const Directory &cDir, const String &cName, int nOpenMode=O_RDONLY)
	Construct a FSNode from directory and a name inside that directory. More...

	FSNode (const FileReference &cRef, int nOpenMode=O_RDONLY)
	Construct a FSNode from a file reference. More...

	FSNode (int nFD)
	Construct a FSNode from a file descriptor. More...

	FSNode (const FSNode &cNode)
	Copy contructor. More...

virtual	~FSNode ()
	Destructor. More...

virtual status_t	SetTo (const String &cPath, int nOpenMode=O_RDONLY)
	Open a node using a path. More...

virtual status_t	SetTo (const Directory &cDir, const String &cPath, int nOpenMode=O_RDONLY)
	Open a node using a dir/path pair. More...

virtual status_t	SetTo (const FileReference &cRef, int nOpenMode=O_RDONLY)
	Open the node referred to by the given os::FileReference. More...

virtual status_t	SetTo (int nFD)
	Make the FSNode represent an already open file. More...

virtual status_t	SetTo (const FSNode &cNode)
	Copy another FSNode. More...

virtual void	Unset ()
	Reset the FSNode. More...

virtual bool	IsValid () const
	Check if the node has been properly initialized. More...

virtual status_t	GetStat (struct stat *psStat, bool bUpdateCache=true) const

virtual ino_t	GetInode () const

virtual dev_t	GetDev () const

virtual int	GetMode (bool bUpdateCache=false) const

virtual time_t	GetCTime (bool bUpdateCache=true) const

virtual time_t	GetMTime (bool bUpdateCache=true) const

virtual time_t	GetATime (bool bUpdateCache=true) const

bool	IsDir () const

bool	IsLink () const

bool	IsFile () const

bool	IsCharDev () const

bool	IsBlockDev () const

bool	IsFIFO () const

virtual status_t	GetNextAttrName (String *pcName)
	Read the node's attribute directory. More...

virtual status_t	RewindAttrdir ()
	Reset the attribute directory iterator. More...

virtual ssize_t	WriteAttr (const String &cAttrName, int nFlags, int nType, const void *pBuffer, off_t nPos, size_t nLen)
	Add/update an attribute. More...

virtual ssize_t	ReadAttr (const String &cAttrName, int nType, void *pBuffer, off_t nPos, size_t nLen)
	Read the data held by an attribute. More...

virtual status_t	RemoveAttr (const String &cName)
	Remove an attribute from an FS node. More...

virtual status_t	StatAttr (const String &cName, struct::attr_info *psBuffer)
	Get extended info about an attribute. More...

virtual int	GetFileDescriptor () const

Detailed Description

Description:

See Also

Author: Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

Member Enumeration Documentation

anonymous enum

Enumerator
DEFAULT_BUFFER_SIZE

Constructor & Destructor Documentation

File::File ( )

Description:: Initialize the instance to a known but invalid state. The instance must be successfully initialized with one of the SetTo() members before it can be used.

Author: Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

File::File	(	const String &	cPath,
		int	nOpenMode = `O_RDONLY`
	)

Description:: Open the file pointed to by cPath. The node must be a regular file or a symlink pointing at a regular file. Anything else will cause and errno_exception(EINVAL) exception to be thrown.

Parameters

cPath The file to open. The path can eigther be absolute (starting with "/") or relative to the current working directory.

nOpenMode

 Flags controling how the file should be opened. The value
 should be one of the O_RDONLY, O_WRONLY, or O_RDWR. In addition
 the following flags can be bitwise or'd in to further control
 the operation:

 - O_TRUNC  trunate the size to 0.
 - O_APPEND automatically move the file-pointer to the end
            of the file before each write (only valid for files)
 - O_NONBLOCK       open the file in non-blocking mode. This is only
            relevant for named pipes and PTY's.
 - O_NOCTTY Don't make the file controlling TTY even if \p cPath
            points to a PTY.

Author: Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

References os::FSNode::GetMode().

File::File	(	const Directory &	cDir,
		const String &	cPath,
		int	nOpenMode = `O_RDONLY`
	)

Description:: Look at File( const std::string& cPath, int nOpenMode ) for a more detailed description.

Parameters

cDir	The directory to use as a base for `cPath`
cPath	Path relative to `cPath`.
nOpenMode	Flags controlling how to open the file. See File( const std::string& cPath, int nOpenMode ) for a full description.

See Also: File( const std::string& cPath, int nOpenMode )

Author: Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

References os::FSNode::GetMode().

File::File	(	const FileReference &	cRef,
		int	nOpenMode = `O_RDONLY`
	)

Description:: Look at File( const std::string& cPath, int nOpenMode ) for a more detailed description.

Parameters

cRef	Reference to the file to open.
nOpenMode	Flags controlling how to open the file. See File( const std::string& cPath, int nOpenMode ) for a full description.

See Also: File( const std::string& cPath, int nOpenMode )

Author: Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

References os::FSNode::GetMode().

File::File ( const FSNode & cNode )

Description:: This constructor can be used to "downcast" an os::FSNode to a os::File. The FSNode must represent a regular file, pipe, or PTY. Attempts to convert symlinks and directories will cause an errno_exception(EINVAL) exception to be thrown.

Parameters

cNode The FSNode to downcast.

Author: Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

References os::FSNode::GetMode().

File::File ( int nFD )

Description:: Construct a file object from a open filedescriptor.

Note: The file descriptor will be close when the object is deleted.

Warning:

Parameters

\return

Error codes:

Since: 0.3.7

See Also

Author: Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

References os::FSNode::GetMode().

File::File ( const File & cFile )

Description:: This constructor will make an independent copy of cFile. The copy and original will have their own file pointers and they will have their own attribute directory iterators (see note).

Note:: The attribute directory iterator will not be cloned so when FSNode::GetNextAttrName() is called for the first time it will return the first attribute name even if the iterator was not located at the beginning of the originals attribute directory.

Parameters

cFile The file object to copy.

Author: Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

References os::File::Private::m_nBufferSize, and os::File::Private::m_nPosition.

File::~File ( )

virtual

References Flush(), os::File::Private::m_bDirty, and os::File::Private::m_pBuffer.

Member Function Documentation

status_t File::FDChanged	(	int	nNewFD,
		const struct stat &	sStat
	)

virtual

Reimplemented from os::FSNode.

References Flush(), os::FSNode::IsValid(), os::File::Private::m_bDirty, and os::File::Private::m_nValidBufSize.

status_t File::Flush ( void )

Note:: Flush() will be called automatically by the destructor if there is unwritten data in the buffer.

Returns: On success 0 will be returned. On failure -1 will be returned and a error code will be stored in the global variable "errno".

Author: Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

References os::FSNode::GetFileDescriptor(), os::File::Private::m_bDirty, os::File::Private::m_cMutex, os::File::Private::m_nBufPos, os::File::Private::m_nValidBufSize, and os::File::Private::m_pBuffer.

Referenced by FDChanged(), os::RegistrarManager::RegisterTypeIconFromRes(), SetBufferSize(), WritePos(), and ~File().

int File::GetBufferSize ( ) const

Returns: The files buffer size in bytes. A value of 0 means the file is unbuffered.

See Also: SetBufferSize()

Author: Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

References os::File::Private::m_nBufferSize.

off_t File::GetSize ( bool bUpdateCache = true ) const

virtual

Reimplemented from os::FSNode.

References os::FSNode::GetSize(), os::File::Private::m_cMutex, os::File::Private::m_nBufPos, and os::File::Private::m_nValidBufSize.

Referenced by Seek().

ssize_t File::Read	(	void *	pBuffer,
		ssize_t	nSize
	)

virtual

Implements os::StreamableIO.

References os::File::Private::m_cMutex, os::File::Private::m_nPosition, and ReadPos().

ssize_t File::ReadPos	(	off_t	nPos,
		void *	pBuffer,
		ssize_t	nSize
	)

virtual

Implements os::SeekableIO.

References os::FSNode::GetFileDescriptor(), os::File::Private::m_cMutex, os::File::Private::m_nBufferSize, os::File::Private::m_nBufPos, os::File::Private::m_nValidBufSize, and os::File::Private::m_pBuffer.

Referenced by Read().

off_t File::Seek	(	off_t	nPos,
		int	nMode
	)

virtual

Description:

Note:

Warning:

Parameters

\return

Error codes:

See Also

Author: Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

Implements os::SeekableIO.

References GetSize(), os::File::Private::m_cMutex, and os::File::Private::m_nPosition.

status_t File::SetBufferSize ( int nBufferSize )

Description:: By default the os::File class use a 32KB internal memory buffer to cache resently read/written data. Normally you the buffer can greatly increase the performance since it reduce the number of kernel-calls when doing multiple small reads or writes on the file. There is cases however where it is beneficial to increase the buffer size or even to disabling buffering entirely.

If you read/write large chunks of data at the time the buffer might impose more overhead than gain and it could be a good idea to disable the buffering entirely by setting the buffer size to 0. When for example streaming video the amount of data read are probably going to be much larger than the buffer anyway and each byte is only read once by the application and if the application read the file in reasonably sized chunks the extra copy imposed by reading the data into the internal buffer and then copy it to the callers buffer will only decrease the performance.

Parameters

nBufferSize The buffer size in bytes. If the size is set to 0 the file will be unbuffered and each call to Read()/Write() and ReadPos()/WritePos() will translate directly to kernel calls.

Returns: On success 0 is returned. If there was not enough memory for the new buffer -1 will be returned and the global variable "errno" will be set to ENOMEM.