fs::blocking::FileDescriptor Class Reference

#include <userver/fs/blocking/file_descriptor.hpp>

Detailed Description

A file descriptor wrapper.

The file is closed in the destructor

Note

The operations on the file are blocking and not thread-safe

Definition at line 27 of file file_descriptor.hpp.

Public Member Functions
	FileDescriptor ()
	Default constructor.
	FileDescriptor (FileDescriptor &&other) noexcept
FileDescriptor &	operator= (FileDescriptor &&other) noexcept
bool	IsOpen () const noexcept
	Checks if the file is open.
void	Close () &&
	Closes the file manually.
int	GetNative () const noexcept
	Returns the native file handle.
int	Release () &&
	Passes the ownership of the file descriptor to the caller.
void	Write (std::string_view contents)
	Writes data to the file.
void	Write (std::span< const struct iovec > contents)
	Writes data to the file, has no IOV_MAX limits on contents.size().
std::size_t	Read (char *buffer, std::size_t max_size)
	Reads data from the file at current offset.
void	Seek (std::size_t offset_in_bytes)
	Sets the file read/write offset from the beginning of the file.
void	FSync ()
	Makes sure the written data is actually stored on disk.
std::size_t	GetSize () const
	Fetches the file size.

Static Public Member Functions
static FileDescriptor	Open (utils::zstring_view path, OpenMode flags, boost::filesystem::perms perms=boost::filesystem::perms::owner_read|boost::filesystem::perms::owner_write)
	Open a file using ::open.
static FileDescriptor	OpenDirectory (utils::zstring_view path)
	Open a directory node.
static FileDescriptor	AdoptFd (int fd) noexcept
	Use the file descriptor directly.
static FileDescriptor	DupFd (int fd) noexcept
	Duplicate the file descriptor.

Constructor & Destructor Documentation

FileDescriptor()

fs::blocking::FileDescriptor::FileDescriptor

(

)

Default constructor.

Note

The file descriptor is not open

Member Function Documentation

Close()

void fs::blocking::FileDescriptor::Close

(

)

&&

Closes the file manually.

Exceptions

std::runtime_error

FSync()

void fs::blocking::FileDescriptor::FSync

(

)

Makes sure the written data is actually stored on disk.

Exceptions

std::runtime_error

GetSize()

std::size_t fs::blocking::FileDescriptor::GetSize

(

)

const

Fetches the file size.

Exceptions

std::runtime_error

IsOpen()

bool fs::blocking::FileDescriptor::IsOpen ( ) const

noexcept

Checks if the file is open.

Note

Operations can only be performed on an open FileDescriptor.

Open()

FileDescriptor fs::blocking::FileDescriptor::Open ( utils::zstring_view path, OpenMode flags, boost::filesystem::perms perms = boost::filesystem::perms::owner_read|boost::filesystem::perms::owner_write )

static

Open a file using ::open.

Exceptions

std::runtime_error

OpenDirectory()

FileDescriptor fs::blocking::FileDescriptor::OpenDirectory ( utils::zstring_view path )

static

Open a directory node.

Note

The only valid operation for such a FileDescriptor is FSync.

Exceptions

std::runtime_error

Read()

std::size_t fs::blocking::FileDescriptor::Read	(	char *	buffer,
		std::size_t	max_size )

Reads data from the file at current offset.

Returns

The amount of bytes actually acquired, which can be equal to max_size, or less on end-of-file

Exceptions

std::runtime_error

Seek()

void fs::blocking::FileDescriptor::Seek

(

std::size_t

offset_in_bytes

)

Sets the file read/write offset from the beginning of the file.

Exceptions

std::runtime_error

Write() [1/2]

void fs::blocking::FileDescriptor::Write

(

std::span< const struct iovec >

contents

)

Writes data to the file, has no IOV_MAX limits on contents.size().

Warning

Unless FSync is called, there is no guarantee the data is stored on disk safely.

Exceptions

std::runtime_error

Write() [2/2]

void fs::blocking::FileDescriptor::Write

(

std::string_view

contents

)

Writes data to the file.

Warning

Unless FSync is called, there is no guarantee the data is stored on disk safely.

Exceptions

std::runtime_error

Friends And Related Symbol Documentation

TempFile

friend class TempFile

friend

Definition at line 100 of file file_descriptor.hpp.

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

• userver/fs/blocking/file_descriptor.hpp