Common operations on file descriptors. More...

#include <sys.h>

Inheritance diagram for wreport::sys::FileDescriptor:

Public Member Functions
	FileDescriptor (FileDescriptor &&o)

	FileDescriptor (int fd)

	FileDescriptor (const FileDescriptor &o)=default

FileDescriptor &	operator= (const FileDescriptor &o)=default

virtual void	throw_error (const char *desc)
	Throw an exception based on errno and the given message. More...

virtual void	throw_runtime_error (const char *desc)
	Throw a runtime_error unrelated from errno. More...

bool	is_open () const
	Check if the file descriptor is open (that is, if it is not -1)

void	close ()
	Close the file descriptor, setting its value to -1. More...

void	fstat (struct stat &st)

void	fchmod (mode_t mode)

void	futimens (const struct ::timespec ts[2])

void	fsync ()

void	fdatasync ()

int	dup ()

size_t	read (void *buf, size_t count)

bool	read_all_or_retry (void *buf, size_t count)
	Read `count` bytes into bufr, retrying partial reads, stopping at EOF. More...

void	read_all_or_throw (void *buf, size_t count)
	Read all the data into buf, throwing runtime_error in case of a partial read.

size_t	write (const void *buf, size_t count)

template<typename Container >
size_t	write (const Container &c)

void	write_all_or_retry (const void *buf, size_t count)
	Write all the data in buf, retrying partial writes.

template<typename Container >
void	write_all_or_retry (const Container &c)

void	write_all_or_throw (const void *buf, size_t count)
	Write all the data in buf, throwing runtime_error in case of a partial write.

template<typename Container >
void	write_all_or_throw (const Container &c)

off_t	lseek (off_t offset, int whence=SEEK_SET)

size_t	pread (void *buf, size_t count, off_t offset)

size_t	pwrite (const void *buf, size_t count, off_t offset)

template<typename Container >
size_t	pwrite (const Container &c, off_t offset)

void	ftruncate (off_t length)

MMap	mmap (size_t length, int prot, int flags, off_t offset=0)

bool	ofd_setlk (struct ::flock &)
	Open file description locks F_OFD_SETLK operation. More...

bool	ofd_setlkw (struct ::flock &, bool retry_on_signal=true)
	Open file description locks F_OFD_SETLKW operation. More...

bool	ofd_getlk (struct ::flock &)
	Open file description locks F_OFD_GETLK operation. More...

void	sendfile (FileDescriptor &out_fd, off_t offset, size_t count)
	Call sendfile with this file as in_fd, falling back on write if it is not available. More...

int	getfl ()
	Get open flags for the file.

void	setfl (int flags)
	Set open flags for the file.

	operator int () const

Protected Attributes
int	fd = -1

Detailed Description

Common operations on file descriptors.

Except when documented otherwise, methods of this class are just thin wrappers around the libc functions with the same name, that check error results and throw exceptions if the functions failed.

Implementing what to do on construction and destruction is left to the subclassers: at the FileDescriptor level, the destructor does nothing and leaves the file descriptor open.

Member Function Documentation

◆ close()

void wreport::sys::FileDescriptor::close ( )

Close the file descriptor, setting its value to -1.

Does nothing if the file descriptor is already closed

◆ ofd_getlk()

bool wreport::sys::FileDescriptor::ofd_getlk ( struct ::flock & )

Open file description locks F_OFD_GETLK operation.

Returns true if the lock would have been obtainable, false if not.

◆ ofd_setlk()

bool wreport::sys::FileDescriptor::ofd_setlk ( struct ::flock & )

Open file description locks F_OFD_SETLK operation.

Returns true if the lock was obtained, false if acquiring the lock failed.

◆ ofd_setlkw()

bool wreport::sys::FileDescriptor::ofd_setlkw	(	struct ::flock &	,
		bool	retry_on_signal = `true`
	)

Open file description locks F_OFD_SETLKW operation.

Returns true if the lock was obtained, false if a signal was received while waiting for the lock.

If retry_on_signal is true, acquiring the lock is automatically retried in case of signals, and the function always returns true.

◆ read_all_or_retry()

bool wreport::sys::FileDescriptor::read_all_or_retry	(	void *	buf,
		size_t	count
	)

Read count bytes into bufr, retrying partial reads, stopping at EOF.

Return true if count bytes have been read, false in case of eof, and raise an exception in case EOF was found after reading between 0 and count-1 bytes.

◆ sendfile()

void wreport::sys::FileDescriptor::sendfile	(	FileDescriptor &	out_fd,
		off_t	offset,
		size_t	count
	)

Call sendfile with this file as in_fd, falling back on write if it is not available.

Perform retry if data was partially written.

◆ throw_error()

virtual void wreport::sys::FileDescriptor::throw_error ( const char * desc )

virtual

Throw an exception based on errno and the given message.

This can be overridden by subclasses that may have more information about the file descriptor, so that they can generate more descriptive messages.

Reimplemented in wreport::sys::NamedFileDescriptor.

◆ throw_runtime_error()

virtual void wreport::sys::FileDescriptor::throw_runtime_error ( const char * desc )