Namespaces
namespace	System
Classes
class	File
	A File object is just a wrapper around a file descriptor; it represents either an open file, an open directory, or an empty placeholder. More...
class	FileContents
	Provides random access to a file. More...
Functions
void	allocate (const File &file, uint64_t offset, uint64_t bytes)
	Allocate a contiguous range of a file, padding with zeros if necessary.
File	dup (const File &file)
	Clones a file descriptor.
void	fsync (const File &file)
	Flush changes to a File to its underlying storage device.
void	fdatasync (const File &file)
	Flush changes to a File to its underlying storage device, except for atime/mtime.
void	flock (const File &file, int operation)
	Apply or remove an advisory lock on a file or directory.
std::string	tryFlock (const File &file, int operation)
	Apply or remove an advisory lock on a file or directory.
uint64_t	getSize (const File &file)
	Returns the size of the file in bytes.
std::vector< std::string >	lsHelper (DIR *dir, const std::string &path)
std::vector< std::string >	ls (const std::string &path)
	List the contents of a directory by path.
std::vector< std::string >	ls (const File &dir)
	List the contents of an open directory.
File	openDir (const std::string &path)
	Open a directory, creating it if it doesn't exist.
File	openDir (const File &dir, const std::string &child)
	Open a directory relative to an already open directory, creating it if it doesn't exist.
File	openFile (const File &dir, const std::string &child, int flags)
	Open a file.
File	tryOpenFile (const File &dir, const std::string &child, int flags)
	Open a file.
void	remove (const std::string &path)
	Remove the file or directory at path.
void	removeFile (const File &dir, const std::string &path)
	Remove the file relative to an open directory.
void	rename (const File &oldDir, const std::string &oldChild, const File &newDir, const std::string &newChild)
	Rename a file.
void	syncDir (const std::string &path)
	Open a directory, fsync it, and close it.
void	truncate (const File &file, uint64_t bytes)
	Shrink or grow a file to the specified length, padding with zeros if necessary.
std::string	mkdtemp ()
	Return a path to a temporary directory.
ssize_t	write (int fildes, const void *data, uint64_t dataLen)
	A wrapper around write that retries interrupted calls.
ssize_t	write (int fildes, std::initializer_list< std::pair< const void *, uint64_t >> data)
	A wrapper around write that retries interrupted calls.
Variables
bool	skipFsync
	Set to true in some unit tests to skip fsync() and fdatasync(), which can speeds up some tests significantly.

Function Documentation

void LogCabin::Storage::FilesystemUtil::allocate	(	const File &	file,
		uint64_t	offset,
		uint64_t	bytes
	)

Allocate a contiguous range of a file, padding with zeros if necessary.

See man 3 posix_fallocate. Does not fsync the file.

Definition at line 94 of file FilesystemUtil.cc.

File LogCabin::Storage::FilesystemUtil::dup ( const File & file )

Clones a file descriptor.

See man 2 dup.

Parameters:

file	An open file descriptor.

Returns:: A copy of 'file' with a new file descriptor.

Definition at line 106 of file FilesystemUtil.cc.

void LogCabin::Storage::FilesystemUtil::fsync ( const File & file )

Flush changes to a File to its underlying storage device.

See skipFsync.

Parameters:

file	An open file descriptor.

Definition at line 117 of file FilesystemUtil.cc.

void LogCabin::Storage::FilesystemUtil::fdatasync ( const File & file )

Flush changes to a File to its underlying storage device, except for atime/mtime.

See fdatasync man page.

Parameters:

file	An open file descriptor. See skipFsync.

Definition at line 128 of file FilesystemUtil.cc.

void LogCabin::Storage::FilesystemUtil::flock	(	const File &	file,
		int	operation
	)

Apply or remove an advisory lock on a file or directory.

See man 2 flock. PANICs if any errors are encountered, even EWOULDBLOCK (see tryFlock).

Definition at line 140 of file FilesystemUtil.cc.

std::string LogCabin::Storage::FilesystemUtil::tryFlock	(	const File &	file,
		int	operation
	)

Apply or remove an advisory lock on a file or directory.

See man 2 flock.

Parameters:

file	File or directory to lock.
operation	LOCK_SH, LOCK_EX, or LOCK_UN, usually ORed with LOCK_NB.

Returns:: If successful, returns the empty string. If the operation would have blocked, returns a non-empty string with detailed information.

Definition at line 148 of file FilesystemUtil.cc.

uint64_t LogCabin::Storage::FilesystemUtil::getSize ( const File & file )

Returns the size of the file in bytes.

Definition at line 169 of file FilesystemUtil.cc.

std::vector<std::string> LogCabin::Storage::FilesystemUtil::lsHelper	(	DIR *	dir,
		const std::string &	path
	)

Definition at line 180 of file FilesystemUtil.cc.

std::vector< std::string > LogCabin::Storage::FilesystemUtil::ls ( const std::string & path )

List the contents of a directory by path.

Panics if the 'path' is not a directory.

Parameters:

path	The path to the directory whose contents to list.

Returns:: The names of the directory entries in the order returned by readdir. The caller will often want to prepend 'path' and a slash to these to form a path.

Definition at line 217 of file FilesystemUtil.cc.

std::vector< std::string > LogCabin::Storage::FilesystemUtil::ls ( const File & dir )

List the contents of an open directory.

Panics if 'dir' is not a directory.

Parameters:

dir	An open file descriptor to the directory whose contents to list.

Returns:: The names of the directory entries in the order returned by readdir.

Definition at line 223 of file FilesystemUtil.cc.

File LogCabin::Storage::FilesystemUtil::openDir ( const std::string & path )

Open a directory, creating it if it doesn't exist.

Definition at line 229 of file FilesystemUtil.cc.

File LogCabin::Storage::FilesystemUtil::openDir	(	const File &	dir,
		const std::string &	child
	)

Open a directory relative to an already open directory, creating it if it doesn't exist.

Definition at line 253 of file FilesystemUtil.cc.

File LogCabin::Storage::FilesystemUtil::openFile	(	const File &	dir,
		const std::string &	child,
		int	flags
	)

Open a file.

See man 2 openat.

Panics if the file could not be opened; see tryOpenFile() if this isn't what you want.

Definition at line 277 of file FilesystemUtil.cc.

File LogCabin::Storage::FilesystemUtil::tryOpenFile	(	const File &	dir,
		const std::string &	child,
		int	flags
	)

Open a file.

See man 2 openat.

Returns a default-constructed File object if the file could not be opened due to EEXIST or ENOENT; see openFile() if this isn't what you want.

Definition at line 289 of file FilesystemUtil.cc.

void LogCabin::Storage::FilesystemUtil::remove ( const std::string & path )

Remove the file or directory at path.

If path is a directory, its contents will also be removed. If path does not exist, this returns without an error. This operation is not atomic but is idempotent.

Definition at line 303 of file FilesystemUtil.cc.

void LogCabin::Storage::FilesystemUtil::removeFile	(	const File &	dir,
		const std::string &	path
	)

Remove the file relative to an open directory.

If path does not exist, this returns without an error. This does not fsync the directory.

Parameters:

dir	An open file descriptor to the directory containing path.
path	The path of the file to remove, relative to dirFd. This must be a file; it may not be a directory.

Definition at line 322 of file FilesystemUtil.cc.

void LogCabin::Storage::FilesystemUtil::rename	(	const File &	oldDir,
		const std::string &	oldChild,
		const File &	newDir,
		const std::string &	newChild
	)

Rename a file.

See man 2 renameat. This does not fsync the directories.

Definition at line 334 of file FilesystemUtil.cc.

void LogCabin::Storage::FilesystemUtil::syncDir ( const std::string & path )

Open a directory, fsync it, and close it.

This is useful to fsync a directory after creating a file or directory within it. See skipFsync.

Definition at line 349 of file FilesystemUtil.cc.

void LogCabin::Storage::FilesystemUtil::truncate	(	const File &	file,
		uint64_t	bytes
	)

Shrink or grow a file to the specified length, padding with zeros if necessary.

See man 2 ftruncate. Does not fsync the file.

Definition at line 369 of file FilesystemUtil.cc.

std::string LogCabin::Storage::FilesystemUtil::mkdtemp ( )

Return a path to a temporary directory.

Definition at line 379 of file FilesystemUtil.cc.

ssize_t LogCabin::Storage::FilesystemUtil::write	(	int	fildes,
		const void *	data,
		uint64_t	dataLen
	)

A wrapper around write that retries interrupted calls.

Parameters:

fildes	The file handle on which to write data.
data	A pointer to the data to write.
dataLen	The number of bytes of 'data' to write.

Returns:: Either -1 with errno set, or the number of bytes requested to write. This wrapper will never return -1 with errno set to EINTR.

Definition at line 396 of file FilesystemUtil.cc.

ssize_t LogCabin::Storage::FilesystemUtil::write	(	int	fildes,
		std::initializer_list< std::pair< const void *, uint64_t >>	data
	)

A wrapper around write that retries interrupted calls.

Parameters:

fildes	The file handle on which to write data.
data	An I/O vector of data to write (pointer, length pairs).

Returns:: Either -1 with errno set, or the number of bytes requested to write. This wrapper will never return -1 with errno set to EINTR.

Definition at line 402 of file FilesystemUtil.cc.

Variable Documentation

bool LogCabin::Storage::FilesystemUtil::skipFsync

Set to true in some unit tests to skip fsync() and fdatasync(), which can speeds up some tests significantly.

Definition at line 36 of file FilesystemUtil.cc.

Namespaces

Classes

Functions

Variables

Function Documentation

Variable Documentation