fs::blocking::FileDescriptor Class Reference

Table of Contents

• Public Member Functions
• Static Public Member Functions
• Friends
• Detailed Description
• Member Function Documentation
• Close()
• FSync()
• GetSize()
• IsOpen()
• Open()
• OpenDirectory()
• Read()
• Seek()
• Write()
• Friends And Related Symbol Documentation
• TempFile

A file descriptor wrapper. More...

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

Public Member Functions
	FileDescriptor (FileDescriptor &&other) noexcept
FileDescriptor &	operator= (FileDescriptor &&other) noexcept
bool	IsOpen () const
	Checks if the file is open.
void	Close () &&
	Closes the file manually.
int	GetNative () const
	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.
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 (const std::string &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 (const std::string &path)
	Open a directory node.
static FileDescriptor	AdoptFd (int fd) noexcept
	Use the file descriptor directly.

Friends
class	TempFile

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 22 of file file_descriptor.hpp.

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

Checks if the file is open.

Note

Operations can only be performed on an open FileDescriptor.

Open()

static FileDescriptor fs::blocking::FileDescriptor::Open ( const std::string &  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()

static FileDescriptor fs::blocking::FileDescriptor::OpenDirectory ( const std::string &  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()

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 85 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