SC::FileDescriptor Struct Reference

Open, read and write to/from a file descriptor (like a file or pipe). More...

#include <File.h>

Inheritance diagram for SC::FileDescriptor:

Public Types
enum	SeekMode {   SeekStart ,   SeekEnd ,   SeekCurrent }
	How the offset to FileDescriptor::seek is defined. More...

Public Member Functions
Result	openForWriteToDevNull ()
	Opens a file descriptor handle for writing to /dev/null or equivalent on current OS.
Result	open (StringSpan path, FileOpen mode)
	Opens a file descriptor handle from a file system path.
Result	setBlocking (bool blocking)
	Set blocking mode (read / write waiting for I/O).
Result	setInheritable (bool inheritable)
	Set inheritable flag (visibility to child processes).
Result	isInheritable (bool &hasValue) const
	Queries the inheritable state of this descriptor.
Result	read (Span< char > data, Span< char > &actuallyRead, uint64_t offset)
	Reads bytes at offset into user supplied span.
Result	read (Span< uint8_t > data, Span< uint8_t > &actuallyRead, uint64_t offset)
	Reads bytes at offset into user supplied span.
Result	read (Span< char > data, Span< char > &actuallyRead)
	Reads bytes from current position (FileDescriptor::seek) into user supplied Span.
Result	read (Span< uint8_t > data, Span< uint8_t > &actuallyRead)
	Reads bytes from current position (FileDescriptor::seek) into user supplied Span.
template<typename T >
Result	readUntilEOF (T &destination)
	Reads into a given dynamic buffer until End of File (EOF) is signaled.
Result	write (Span< const char > data, uint64_t offset)
	Writes bytes at offset from start of the file descriptor.
Result	write (Span< const uint8_t > data, uint64_t offset)
	Writes bytes at offset from start of the file descriptor.
Result	write (Span< const char > data)
	Writes bytes from current position (FileDescriptor::seek) of the file descriptor.
Result	write (Span< const uint8_t > data)
	Writes bytes from current position (FileDescriptor::seek) of the file descriptor.
Result	seek (SeekMode seekMode, uint64_t offset)
	Changes the current position in the file descriptor, if seekable.
Result	currentPosition (size_t &position) const
	Gets current descriptor position (if seekable)
Result	sizeInBytes (size_t &sizeInBytes) const
	Gets total file size in bytes (if seekable)
	UniqueHandle ()=default
	UniqueHandle (const UniqueHandle &v)=delete
	UniqueHandle (UniqueHandle &&v)
	UniqueHandle (const Handle &externalHandle)

Friends
struct	File

Detailed Description

Open, read and write to/from a file descriptor (like a file or pipe).

Member Enumeration Documentation

SeekMode

enum SC::FileDescriptor::SeekMode

How the offset to FileDescriptor::seek is defined.

Enumerator
SeekStart	Offset to FileDescriptor::seek is to be applied from start of descriptor.
SeekEnd	Offset to FileDescriptor::seek is to be applied (backwards) from end of descriptor.
SeekCurrent	Offset to FileDescriptor::seek is to be applied from current descriptor position.

Member Function Documentation

currentPosition()

Result SC::FileDescriptor::currentPosition

(

size_t &

position

)

const

Gets current descriptor position (if seekable)

Parameters

position

(output) current position of file descriptor

Returns

Valid result if seek succeeds

isInheritable()

Result SC::FileDescriptor::isInheritable

(

bool &

hasValue

)

const

Queries the inheritable state of this descriptor.

Parameters

hasValue

will be set to true if the file descriptor has inheritable file set

Returns

Valid Result if the inheritable flag has been queried successfully

open()

Result SC::FileDescriptor::open	(	StringSpan	path,
		FileOpen	mode )

Opens a file descriptor handle from a file system path.

Parameters

path	The absolute path to file. It MUST be encoded in ASCII,UTF-8/16 on Windows, ASCII,UTF-8 on POSIX.
mode	The mode used to open file (read-only, write-append etc.)

Returns

Valid Result if file is opened successfully

openForWriteToDevNull()

Result SC::FileDescriptor::openForWriteToDevNull

(

)

Opens a file descriptor handle for writing to /dev/null or equivalent on current OS.

Returns

true if file has been opened successfully

read() [1/4]

Result SC::FileDescriptor::read	(	Span< char >	data,
		Span< char > &	actuallyRead )

Reads bytes from current position (FileDescriptor::seek) into user supplied Span.

Parameters

data	Span of bytes where data should be written to
actuallyRead	A sub-span of data of the actually read bytes. A zero sized span means EOF.

Returns

Valid result if read succeeded

read() [2/4]

Result SC::FileDescriptor::read	(	Span< char >	data,
		Span< char > &	actuallyRead,
		uint64_t	offset )

Reads bytes at offset into user supplied span.

Parameters

data	Span of bytes where data should be written to
actuallyRead	A sub-span of data of the actually read bytes. A zero sized span means EOF.
offset	Offset from begin of the file descriptor where read should be started

Returns

Valid result if read succeeded

read() [3/4]

Result SC::FileDescriptor::read	(	Span< uint8_t >	data,
		Span< uint8_t > &	actuallyRead )

Reads bytes from current position (FileDescriptor::seek) into user supplied Span.

Parameters

data	Span of bytes where data should be written to
actuallyRead	A sub-span of data of the actually read bytes. A zero sized span means EOF.

Returns

Valid result if read succeeded

read() [4/4]

Result SC::FileDescriptor::read	(	Span< uint8_t >	data,
		Span< uint8_t > &	actuallyRead,
		uint64_t	offset )

Reads bytes at offset into user supplied span.

Parameters

data	Span of bytes where data should be written to
actuallyRead	A sub-span of data of the actually read bytes. A zero sized span means EOF.
offset	Offset from begin of the file descriptor where read should be started

Returns

Valid result if read succeeded

readUntilEOF()

template<typename T >

Result SC::FileDescriptor::readUntilEOF ( T & destination )

inline

Reads into a given dynamic buffer until End of File (EOF) is signaled.

It works also for non-seekable file descriptors (stdout / in / err).

Template Parameters

T	Type of the destination buffer implementing IGrowableBuffer interface (String, SmallString, Buffer)

Parameters

destination

A destination buffer to write to (it will be resized as needed)

Returns

Valid result if read succeeded until EOF

seek()

Result SC::FileDescriptor::seek	(	SeekMode	seekMode,
		uint64_t	offset )

Changes the current position in the file descriptor, if seekable.

Parameters

seekMode	How the offset is defined (from start, end, current)
offset	An offset to be applied according to seekMode to this descriptor

Returns

Valid result if seek succeeds

setBlocking()

Result SC::FileDescriptor::setBlocking

(

bool

blocking

)

Set blocking mode (read / write waiting for I/O).

Can be set also during open with OpenOptions.

Parameters

blocking

true to set file to blocking mode

Returns

true if blocking mode has been changed successfully

setInheritable()

Result SC::FileDescriptor::setInheritable

(

bool

inheritable

)

Set inheritable flag (visibility to child processes).

Can be set also during open with OpenOptions.

Parameters

inheritable

true to set file to blocking mode

Returns

true if blocking mode has been changed successfully

sizeInBytes()

Result SC::FileDescriptor::sizeInBytes

(

size_t &

sizeInBytes

)

const

Gets total file size in bytes (if seekable)

Parameters

sizeInBytes

(output) total size of file

Returns

Valid result if seek succeeds

write() [1/4]

Result SC::FileDescriptor::write

(

Span< const char >

data

)

Writes bytes from current position (FileDescriptor::seek) of the file descriptor.

Parameters

data	Span of bytes containing the data to write

Returns

Valid result if write succeeded

write() [2/4]

Result SC::FileDescriptor::write	(	Span< const char >	data,
		uint64_t	offset )

Writes bytes at offset from start of the file descriptor.

Parameters

data	Span of bytes containing the data to write
offset	Offset from begin of file descriptor to start writing

Returns

Valid result if write succeeded

write() [3/4]

Result SC::FileDescriptor::write

(

Span< const uint8_t >

data

)

Writes bytes from current position (FileDescriptor::seek) of the file descriptor.

Parameters

data	Span of bytes containing the data to write

Returns

Valid result if write succeeded

write() [4/4]

Result SC::FileDescriptor::write	(	Span< const uint8_t >	data,
		uint64_t	offset )

Writes bytes at offset from start of the file descriptor.

Parameters

data	Span of bytes containing the data to write
offset	Offset from begin of file descriptor to start writing

Returns

Valid result if write succeeded

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

• File.h