wreport::sys Namespace Reference

Operating system functions. More...

Data Structures
struct	Clock
	Access to clock_gettime. More...
class	File
	File in the file system. More...
class	FileDescriptor
	Common operations on file descriptors. More...
struct	ManagedNamedFileDescriptor
	File descriptor that gets automatically closed in the object destructor. More...
class	MMap
	Wraps a mmapped memory area, unmapping it on destruction. More...
class	NamedFileDescriptor
	File descriptor with a name. More...
struct	OverrideEnvironment
	Override an environment variable for the duration of this object. More...
struct	OverrideRlimit
	Override a soft resource limit during the lifetime of the object. More...
struct	Path
	Wrap a path on the file system opened with O_PATH. More...
class	PreserveFileTimes
	RAII mechanism to save restore file times at the end of some file operations. More...
class	TempBuffer
	RAII local memory buffer. More...
class	Tempdir
	Open a temporary directory. More...
class	Tempfile
	Open a temporary file. More...

Functions
std::filesystem::path	with_suffix (const std::filesystem::path &path, const std::string &suffix)
	Return the path with suffix appended to its filename.
std::unique_ptr< struct stat >	stat (const char *pathname)
	stat() the given file and return the struct stat with the results.
std::unique_ptr< struct stat >	stat (const std::string &pathname)
	stat() the given file and return the struct stat with the results.
std::unique_ptr< struct stat >	stat (const std::filesystem::path &path)
	stat() the given file and return the struct stat with the results.
void	stat (const char *pathname, struct stat &st)
	stat() the given file filling in the given structure.
void	stat (const std::string &pathname, struct stat &st)
	stat() the given file filling in the given structure.
void	stat (const std::filesystem::path &path, struct stat &st)
	stat() the given file filling in the given structure.
bool	isdir (const std::string &pathname)
	Returns true if the given pathname is a directory, else false.
bool	isblk (const std::string &pathname)
	Same as isdir but checks for block devices.
bool	ischr (const std::string &pathname)
	Same as isdir but checks for character devices.
bool	isfifo (const std::string &pathname)
	Same as isdir but checks for FIFOs.
bool	islnk (const std::string &pathname)
	Same as isdir but checks for symbolic links.
bool	isreg (const std::string &pathname)
	Same as isdir but checks for regular files.
bool	issock (const std::string &pathname)
	Same as isdir but checks for sockets.
time_t	timestamp (const std::filesystem::path &file)
	File mtime.
time_t	timestamp (const std::filesystem::path &file, time_t def)
	File mtime (or def if the file does not exist)
size_t	size (const std::filesystem::path &file)
	File size.
size_t	size (const std::filesystem::path &file, size_t def)
	File size (or def if the file does not exist)
ino_t	inode (const std::filesystem::path &file)
	File inode number.
ino_t	inode (const std::filesystem::path &file, ino_t def)
	File inode number (or 0 if the file does not exist)
bool	access (const std::filesystem::path &s, int m)
	access() a filename
bool	exists (const std::string &s)
	Same as access(s, F_OK);.
std::string	getcwd ()
	Get the absolute path of the current working directory.
void	chdir (const std::string &dir)
	Change working directory.
void	chroot (const std::filesystem::path &dir)
	Change root directory.
mode_t	umask (mode_t mask)
	Change umask (always succeeds and returns the previous umask)
std::filesystem::path	abspath (const std::filesystem::path &path)
	Get the absolute path of a file.
std::string	abspath (const std::string &pathname)
std::filesystem::path	abspath (const char *path)
std::string	read_file (const std::filesystem::path &file)
	Read whole file into memory. Throws exceptions on failure.
std::string	read_file (const std::string &file)
std::string	read_file (const char *file)
void	write_file (const std::filesystem::path &file, const std::string &data, mode_t mode=0777)
	Write data to file, replacing existing contents if it already exists.
void	write_file (const std::string &file, const std::string &data, mode_t mode=0777)
void	write_file (const char *file, const std::string &data, mode_t mode=0777)
void	write_file (const std::filesystem::path &file, const void *data, size_t size, mode_t mode=0777)
	Write data to file, replacing existing contents if it already exists.
void	write_file (const std::string &file, const void *data, size_t size, mode_t mode=0777)
void	write_file (const char *file, const void *data, size_t size, mode_t mode=0777)
void	write_file_atomically (const std::filesystem::path &file, const std::string &data, mode_t mode=0777)
	Write data to file, replacing existing contents if it already exists.
void	write_file_atomically (const std::string &file, const std::string &data, mode_t mode=0777)
void	write_file_atomically (const char *file, const std::string &data, mode_t mode=0777)
void	write_file_atomically (const std::filesystem::path &file, const void *data, size_t size, mode_t mode=0777)
	Write data to file, replacing existing contents if it already exists.
void	write_file_atomically (const std::string &file, const void *data, size_t size, mode_t mode=0777)
bool	unlink_ifexists (const char *file)
	Delete a file if it exists.
bool	unlink_ifexists (const std::string &file)
bool	unlink_ifexists (const std::filesystem::path &file)
bool	rename_ifexists (const std::filesystem::path &src, const std::filesystem::path &dst)
	Move src to dst, without raising exception if src does not exist.
bool	mkdir_ifmissing (const std::filesystem::path &path)
	Create the given directory, if it does not already exists.
bool	makedirs (const std::filesystem::path &path)
	Create all the component of the given directory, including the directory itself.
std::filesystem::path	which (const std::string &name)
	Compute the absolute path of an executable.
void	unlink (const std::filesystem::path &pathname)
	Delete the file using unlink()
void	rmdir (const std::filesystem::path &pathname)
	Remove the directory using rmdir(2)
void	rmtree (const std::filesystem::path &pathname)
	Delete the directory pathname and all its contents.
bool	rmtree_ifexists (const std::filesystem::path &pathname)
	Delete the directory pathname and all its contents.
bool	rmtree_ifexists (const std::string &pathname)
bool	rmtree_ifexists (const char *pathname)
void	rename (const std::string &src_pathname, const std::string &dst_pathname)
	Rename src_pathname into dst_pathname.
void	touch (const std::filesystem::path &pathname, time_t ts)
	Set mtime and atime for the file.
bool	touch_ifexists (const std::filesystem::path &pathname, time_t ts)
	Set mtime and atime for the file.
void	clock_gettime (::clockid_t clk_id, ::timespec &ts)
	Call clock_gettime, raising an exception if it fails.
unsigned long long	timesec_elapsed (const ::timespec &begin, const ::timespec &until)
	Return the time elapsed between two timesec structures, in nanoseconds.
void	getrlimit (int resource, ::rlimit &rlim)
	rlimit wrappers
void	setrlimit (int resource, const ::rlimit &rlim)
	Call setrlimit, raising an exception if it fails.
void	breakpoint ()
	Set a breakpoint at this code location.

Detailed Description

Operating system functions.

Author

Enrico Zini enric.nosp@m.o@en.nosp@m.ricoz.nosp@m.ini..nosp@m.org

Copyright (C) 2007–2018 Enrico Zini enric.nosp@m.o@de.nosp@m.bian..nosp@m.org

Function Documentation

getrlimit()

void wreport::sys::getrlimit	(	int	resource,
		::rlimit &	rlim )

rlimit wrappers

Call getrlimit, raising an exception if it fails

isdir()

bool wreport::sys::isdir

(

const std::string &

pathname

)

Returns true if the given pathname is a directory, else false.

It also returns false if the pathname does not exist.

makedirs()

bool wreport::sys::makedirs

(

const std::filesystem::path &

path

)

Create all the component of the given directory, including the directory itself.

Returns

true if the directory was created, false if it already existed.

mkdir_ifmissing()

bool wreport::sys::mkdir_ifmissing

(

const std::filesystem::path &

path

)

Create the given directory, if it does not already exists.

It will throw an exception if the given pathname already exists but is not a directory.

Returns

true if the directory was created, false if it already existed.

rename()

void wreport::sys::rename	(	const std::string &	src_pathname,
		const std::string &	dst_pathname )

Rename src_pathname into dst_pathname.

This is just a wrapper to the rename(2) system call: source and destination must be on the same file system.

rename_ifexists()

bool wreport::sys::rename_ifexists	(	const std::filesystem::path &	src,
		const std::filesystem::path &	dst )

Move src to dst, without raising exception if src does not exist.

Returns

true if the file was renamed, false if it did not exist

rmtree_ifexists()

bool wreport::sys::rmtree_ifexists

(

const std::filesystem::path &

pathname

)

Delete the directory pathname and all its contents.

If the directory does not exist, it returns false, else true.

stat() [1/6]

std::unique_ptr< struct stat > wreport::sys::stat

(

const char *

pathname

)

stat() the given file and return the struct stat with the results.

If the file does not exist, return NULL. Raises exceptions in case of errors.

Referenced by wreport::sys::FileDescriptor::close(), wreport::sys::Path::fstatat_ifexists(), wreport::sys::Path::lstatat(), wreport::sys::Path::lstatat_ifexists(), wreport::sys::Path::openat_ifexists(), stat(), stat(), and stat().

stat() [2/6]

void wreport::sys::stat	(	const char *	pathname,
		struct stat &	st )

stat() the given file filling in the given structure.

Raises exceptions in case of errors, including if the file does not exist.

References stat().

stat() [3/6]

std::unique_ptr< struct stat > wreport::sys::stat

(

const std::filesystem::path &

path

)

stat() the given file and return the struct stat with the results.

If the file does not exist, return NULL. Raises exceptions in case of errors.

stat() [4/6]

void wreport::sys::stat	(	const std::filesystem::path &	path,
		struct stat &	st )

stat() the given file filling in the given structure.

Raises exceptions in case of errors, including if the file does not exist.

References stat().

stat() [5/6]

std::unique_ptr< struct stat > wreport::sys::stat

(

const std::string &

pathname

)

stat() the given file and return the struct stat with the results.

If the file does not exist, return NULL. Raises exceptions in case of errors.

stat() [6/6]

void wreport::sys::stat	(	const std::string &	pathname,
		struct stat &	st )

stat() the given file filling in the given structure.

Raises exceptions in case of errors, including if the file does not exist.

References stat().

touch()

void wreport::sys::touch	(	const std::filesystem::path &	pathname,
		time_t	ts )

Set mtime and atime for the file.

Throws an error if the file does not exist.

touch_ifexists()

bool wreport::sys::touch_ifexists	(	const std::filesystem::path &	pathname,
		time_t	ts )

Set mtime and atime for the file.

Returns false if the file does not exist.

unlink_ifexists()

bool wreport::sys::unlink_ifexists

(

const char *

file

)

Delete a file if it exists.

If it does not exist, do nothing.

Returns

true if the file was deleted, false if it did not exist

which()

std::filesystem::path wreport::sys::which

(

const std::string &

name

)

Compute the absolute path of an executable.

If name is specified as a partial path, it ensures it is made absolute. If name is not specified as a path, it looks for the executable in $PATH and return its absolute pathname.

with_suffix()

std::filesystem::path wreport::sys::with_suffix	(	const std::filesystem::path &	path,
		const std::string &	suffix )

Return the path with suffix appended to its filename.

path needs to have a filename, otherwise the function will throw std::invalid_argument

write_file() [1/2]

void wreport::sys::write_file	(	const std::filesystem::path &	file,
		const std::string &	data,
		mode_t	mode = 0777 )

Write data to file, replacing existing contents if it already exists.

New files are created with the given permission mode, honoring umask. Permissions of existing files do not change.

write_file() [2/2]

void wreport::sys::write_file	(	const std::filesystem::path &	file,
		const void *	data,
		size_t	size,
		mode_t	mode = 0777 )

Write data to file, replacing existing contents if it already exists.

New files are created with the given permission mode, honoring umask. Permissions of existing files do not change.

References size().

write_file_atomically() [1/2]

void wreport::sys::write_file_atomically	(	const std::filesystem::path &	file,
		const std::string &	data,
		mode_t	mode = 0777 )

Write data to file, replacing existing contents if it already exists.

Files are created with the given permission mode, honoring umask. If the file already exists, its mode is ignored.

Data is written to a temporary file, then moved to its final destination, to ensure an atomic operation.

write_file_atomically() [2/2]

void wreport::sys::write_file_atomically	(	const std::filesystem::path &	file,
		const void *	data,
		size_t	size,
		mode_t	mode = 0777 )

Write data to file, replacing existing contents if it already exists.

Files are created with the given permission mode, honoring umask. If the file already exists, its mode is ignored.

Data is written to a temporary file, then moved to its final destination, to ensure an atomic operation.

References size().