#include <FileHandle.h>

Inherited by DirectSerial, File, FileLike, LocalFileHandle, SerialWireOutput, UARTSerial, UnbufferedSerial, and Sink.

Public Member Functions
virtual ssize_t	read (void *buffer, size_t size)=0
	Read the contents of a file into a buffer.
virtual ssize_t	write (const void *buffer, size_t size)=0
	Write the contents of a buffer to a file.
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.
virtual int	close ()=0
	Close a file.
virtual int	sync ()
	Flush any buffers associated with the file.
virtual int	isatty ()
	Check if the file in an interactive terminal device.
virtual off_t	tell ()
	Get the file position of the file.
virtual void	rewind ()
	Rewind the file position to the beginning of the file.
virtual off_t	size ()
	Get the size of the file.
virtual int	truncate (off_t length)
	Truncate or extend a file.
	MBED_DEPRECATED_SINCE ("mbed-os-5.4","Replaced by FileHandle::seek") virtual off_t lseek(off_t offset
	Move the file position to a given offset from a given location.
	MBED_DEPRECATED_SINCE ("mbed-os-5.4","Replaced by FileHandle::sync") virtual int fsync()
	Flush any buffers associated with the FileHandle, ensuring it is up to date on disk.
	MBED_DEPRECATED_SINCE ("mbed-os-5.4","Replaced by FileHandle::size") virtual off_t flen()
	Find the length of the file.
virtual int	set_blocking (bool blocking)
	Set blocking or nonblocking mode of the file operation like read/write.
virtual bool	is_blocking () const
	Check current blocking or nonblocking mode for file operations.
virtual int	enable_input (bool enabled)
	Enable or disable input.
virtual int	enable_output (bool enabled)
	Enable or disable output.
virtual short	poll (short events) const
	Check for poll event flags You can use or ignore the input parameter.
bool	writable () const
	Definition depends on the subclass implementing FileHandle.
bool	readable () const
	Definition depends on the subclass implementing FileHandle.
virtual void	sigio (Callback< void()> func)
	Register a callback on state change of the file.
Private Member Functions
	MBED_DEPRECATED ("Invalid copy construction of a NonCopyable resource.") NonCopyable(const NonCopyable &)
	NonCopyable copy constructor.
	MBED_DEPRECATED ("Invalid copy assignment of a NonCopyable resource.") NonCopyable &operator
	NonCopyable copy assignment operator.

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

virtual int close ( ) [pure virtual]

Close a file.

Returns:: 0 on success, negative error code on failure

Implemented in UARTSerial, UnbufferedSerial, File, and Stream.

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 UARTSerial.

Definition at line 236 of file FileHandle.h.

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 UARTSerial.

Definition at line 254 of file FileHandle.h.

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 UARTSerial.

Definition at line 218 of file FileHandle.h.

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 UARTSerial, UnbufferedSerial, File, and Stream.

Definition at line 110 of file FileHandle.h.

MBED_DEPRECATED_SINCE	(	"mbed-os-5.4"	,
		"Replaced by FileHandle::seek"
	)

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

Parameters:

offset	The offset from whence to move to
whence	SEEK_SET for the start of the file, SEEK_CUR for the current file position, or SEEK_END for the end of the file.

Returns:: new file position on success, -1 on failure or unsupported

MBED_DEPRECATED_SINCE	(	"mbed-os-5.4"	,
		"Replaced by FileHandle::sync"
	)

Flush any buffers associated with the FileHandle, ensuring it is up to date on disk.

Returns:: 0 on success or un-needed, -1 on error

Definition at line 182 of file FileHandle.h.

MBED_DEPRECATED_SINCE	(	"mbed-os-5.4"	,
		"Replaced by FileHandle::size"
	)

Find the length of the file.

Returns:: Length of the file

Definition at line 194 of file FileHandle.h.

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 UARTSerial, and UnbufferedSerial.

Definition at line 269 of file FileHandle.h.

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 UARTSerial, UnbufferedSerial, File, and Stream.

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 292 of file FileHandle.h.

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 File, and Stream.

Definition at line 130 of file FileHandle.h.

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 UARTSerial, UnbufferedSerial, File, and Stream.

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 UARTSerial.

Definition at line 209 of file FileHandle.h.

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 UARTSerial.

Definition at line 314 of file FileHandle.h.

off_t size ( ) [virtual]

Get the size of the file.

Returns:: Size of the file in bytes

Reimplemented in UnbufferedSerial, File, and Stream.

Definition at line 21 of file FileHandle.cpp.

virtual int sync ( ) [virtual]

Flush any buffers associated with the file.

Returns:: 0 on success, negative error code on failure

Reimplemented in UARTSerial, File, and Stream.

Definition at line 99 of file FileHandle.h.

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 File, and Stream.

Definition at line 121 of file FileHandle.h.

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.

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 281 of file FileHandle.h.

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 UARTSerial, UnbufferedSerial, File, and Stream.

Type:	Library
Created:	17 Dec 2019
Imports:	79
Forks:	0
Commits:	2
Dependents:	2
Dependencies:	0
Followers:	1

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