#include <FileHandle.h>

Inheritance diagram for FileHandle:

Public Member Functions
virtual ssize_t	read (void *buffer, size_t size)=0
	Read the contents of a file into a buffer. More...

virtual ssize_t	write (const void *buffer, size_t size)=0
	Write the contents of a buffer to a file. More...

virtual off_t	seek (off_t offset, int whence=SEEK_SET)=0
	Move the file position to a given offset from from a given location. More...

virtual int	close ()=0
	Close a file. More...

virtual int	sync ()
	Flush any buffers associated with the file. More...

virtual int	isatty ()
	Check if the file in an interactive terminal device. More...

virtual off_t	tell ()
	Get the file position of the file. More...

virtual void	rewind ()
	Rewind the file position to the beginning of the file. More...

virtual off_t	size ()
	Get the size of the file. More...

virtual int	truncate (off_t length)
	Truncate or extend a file. More...

virtual int	set_blocking (bool blocking)
	Set blocking or nonblocking mode of the file operation like read/write. More...

virtual bool	is_blocking () const
	Check current blocking or nonblocking mode for file operations. More...

virtual int	enable_input (bool enabled)
	Enable or disable input. More...

virtual int	enable_output (bool enabled)
	Enable or disable output. More...

virtual short	poll (short events) const
	Check for poll event flags You can use or ignore the input parameter. More...

bool	writable () const
	Definition depends on the subclass implementing FileHandle. More...

bool	readable () const
	Definition depends on the subclass implementing FileHandle. More...

virtual void	sigio (Callback< void()> func)
	Register a callback on state change of the file. More...

Detailed Description

Class FileHandle.

An abstract interface that represents operations on a file-like object. The core functions are read, write and seek, but only a subset of these operations can be provided.

Note: to create a file,

See also: File

Note: Synchronization level: Set by subclass

Definition at line 46 of file FileHandle.h.

Member Function Documentation

◆ read()

virtual ssize_t read	(	void *	buffer,
		size_t	size
	)

pure virtual

Read the contents of a file into a buffer.

Devices acting as FileHandles should follow POSIX semantics:

if no data is available, and nonblocking set, return -EAGAIN
if no data is available, and blocking set, wait until some data is available
If any data is available, call returns immediately

Parameters

buffer	The buffer to read in to
size	The number of bytes to read

Returns: The number of bytes read, 0 at end of file, negative error on failure

Implemented in LocalFileHandle, Stream, BufferedSerial, File, SerialWireOutput, and UnbufferedSerial.

◆ write()

virtual ssize_t write	(	const void *	buffer,
		size_t	size
	)

pure virtual

Write the contents of a buffer to a file.

Devices acting as FileHandles should follow POSIX semantics:

if blocking, block until all data is written
if no data can be written, and nonblocking set, return -EAGAIN
if some data can be written, and nonblocking set, write partial

Parameters

buffer	The buffer to write from
size	The number of bytes to write

Returns: The number of bytes written, negative error on failure

Implemented in LocalFileHandle, Stream, BufferedSerial, File, SerialWireOutput, and UnbufferedSerial.

◆ seek()

virtual off_t seek	(	off_t	offset,
		int	whence = `SEEK_SET`
	)

pure virtual

Move the file position to a given offset from from a given location.

Parameters

offset	The offset from whence to move to
whence	The start of where to seek SEEK_SET to start from beginning of file, SEEK_CUR to start from current position in file, SEEK_END to start from end of file

Returns: The new offset of the file, negative error code on failure

Implemented in Stream, BufferedSerial, File, SerialWireOutput, UnbufferedSerial, and LocalFileHandle.

◆ close()

virtual int close ( )

pure virtual

Close a file.

Returns: 0 on success, negative error code on failure

Implemented in LocalFileHandle, Stream, File, BufferedSerial, SerialWireOutput, and UnbufferedSerial.

◆ sync()

virtual int sync ( )

virtual

Flush any buffers associated with the file.

Returns: 0 on success, negative error code on failure

Reimplemented in LocalFileHandle, Stream, File, and BufferedSerial.

Definition at line 99 of file FileHandle.h.

◆ isatty()

virtual int isatty ( )

virtual

Check if the file in an interactive terminal device.

Returns: True if the file is a terminal; False if the file is not a terminal; Negative error code on failure

Reimplemented in LocalFileHandle, Stream, File, BufferedSerial, SerialWireOutput, and UnbufferedSerial.

Definition at line 110 of file FileHandle.h.

◆ tell()

virtual off_t tell ( )

virtual

Get the file position of the file.

Note: This is equivalent to seek(0, SEEK_CUR)

Returns: The current offset in the file, negative error code on failure

Reimplemented in Stream, and File.

Definition at line 121 of file FileHandle.h.

◆ rewind()

virtual void rewind ( )

virtual

Rewind the file position to the beginning of the file.

Note: This is equivalent to seek(0, SEEK_SET)

Reimplemented in Stream, and File.

Definition at line 130 of file FileHandle.h.

◆ size()

virtual off_t size ( )

virtual

Get the size of the file.

Returns: Size of the file in bytes

Reimplemented in LocalFileHandle, Stream, File, SerialWireOutput, and UnbufferedSerial.

◆ truncate()

virtual int truncate ( off_t length )

virtual

Truncate or extend a file.

The file's length is set to the specified value. The seek pointer is not changed. If the file is extended, the extended area appears as if it were zero-filled.

Parameters

length The requested new length for the file

Returns: Zero on success, negative error code on failure

Reimplemented in File.

Definition at line 151 of file FileHandle.h.

◆ set_blocking()

virtual int set_blocking ( bool blocking )

virtual

Set blocking or nonblocking mode of the file operation like read/write.

Definition depends on the subclass implementing FileHandle. The default is blocking.

Parameters

blocking true for blocking mode, false for nonblocking mode.

Returns: 0 on success; Negative error code on failure

Reimplemented in BufferedSerial.

Definition at line 165 of file FileHandle.h.

◆ is_blocking()

virtual bool is_blocking ( ) const

virtual

Check current blocking or nonblocking mode for file operations.

Returns: true for blocking mode, false for nonblocking mode.

Reimplemented in BufferedSerial.

Definition at line 174 of file FileHandle.h.

◆ enable_input()

virtual int enable_input ( bool enabled )

virtual

Enable or disable input.

Control enabling of device for input. This is primarily intended for temporary power-saving; the overall ability of the device to operate for input and/or output may be fixed at creation time, but this call can allow input to be temporarily disabled to permit power saving without losing device state.

Parameters

enabled true to enable input, false to disable.

Returns: 0 on success; Negative error code on failure

Reimplemented in BufferedSerial, and UnbufferedSerial.

Definition at line 192 of file FileHandle.h.

◆ enable_output()

virtual int enable_output ( bool enabled )

virtual

Enable or disable output.

Control enabling of device for output. This is primarily intended for temporary power-saving; the overall ability of the device to operate for input and/or output may be fixed at creation time, but this call can allow output to be temporarily disabled to permit power saving without losing device state.

Parameters

enabled true to enable output, false to disable.

Returns: 0 on success; Negative error code on failure

Reimplemented in BufferedSerial, and UnbufferedSerial.

Definition at line 210 of file FileHandle.h.

◆ poll()

virtual short poll ( short events ) const

virtual

Check for poll event flags You can use or ignore the input parameter.

You can return all events or check just the events listed in events. Call is nonblocking - returns instantaneous state of events. Whenever an event occurs, the derived class should call the sigio() callback).

Parameters

events bitmask of poll events we're interested in - POLLIN/POLLOUT etc.

Returns: bitmask of poll events that have occurred.

Reimplemented in BufferedSerial, and UnbufferedSerial.

Definition at line 225 of file FileHandle.h.

◆ writable()

bool writable ( ) const

Definition depends on the subclass implementing FileHandle.

For example, if the FileHandle is of type Stream, writable() could return true when there is ample buffer space available for write() calls.

Returns: true if the FileHandle is writable.

Definition at line 237 of file FileHandle.h.

◆ readable()

bool readable ( ) const

Definition depends on the subclass implementing FileHandle.

For example, if the FileHandle is of type Stream, readable() could return true when there is something available to read.

Returns: true when there is something available to read.

Definition at line 248 of file FileHandle.h.

◆ sigio()

virtual void sigio ( Callback< void()> func )

virtual

Register a callback on state change of the file.

The specified callback will be called on state changes such as when the file can be written to or read from.

The callback may be called in an interrupt context and should not perform expensive operations.

Note! This is not intended as an attach-like asynchronous API, but rather as a building block for constructing such functionality.

The exact timing of when the registered function is called is not guaranteed and is susceptible to change. It should be used as a cue to make read/write/poll calls to find the current state.

Parameters

func	Function to call on state change

Reimplemented in BufferedSerial.

Definition at line 270 of file FileHandle.h.

Public Member Functions

Detailed Description

Member Function Documentation

◆ read()

◆ write()

◆ seek()

◆ close()

◆ sync()

◆ isatty()

◆ tell()

◆ rewind()

◆ size()

◆ truncate()

◆ set_blocking()

◆ is_blocking()

◆ enable_input()

◆ enable_output()

◆ poll()

◆ writable()

◆ readable()

◆ sigio()