Get information about, and manipulate symbolic links. More...

#include <SymLink.h>

Inheritance diagram for casacore::SymLink:

Public Member Functions
	SymLink ()
	The default constructor creates a SymLink with path ".". More...

	SymLink (const Path &name)
	Create a SymLink with the given path. More...

	SymLink (const String &name)

	SymLink (const File &name)

	SymLink (const SymLink &that)
	Copy constructor (copy semantics). More...

	~SymLink ()

SymLink &	operator= (const SymLink &that)
	Assignment (copy semantics). More...

void	create (const Path &target, Bool overwrite=True)
	Make a symbolic link to a file given by target. More...

void	create (const String &target, Bool overwrite=True)

void	copy (const Path &target, Bool overwrite=True) const
	Copy the symlink to the target path using the system command cp. More...

void	copy (const String &target, Bool overwrite=True) const

void	move (const Path &target, Bool overwrite=True)
	Move the symlink to the target path using the system command mv. More...

void	move (const String &target, Bool overwrite=True)

void	remove ()
	Remove a symbolic link. More...

Path	readSymLink () const
	Read value of a symbolic link and return it as a Path. More...

Path	followSymLink () const
	As readSymLink, but the entire symlink chain is followed when the symlinks points to other symlinks. More...

Public Member Functions inherited from casacore::File
	File ()
	Construct a File object whose Path is set to the current working directory. More...

	File (const Path &path)
	Construct a File object whose Path is set to the given Path. More...

	File (const String &path)

	File (const File &that)
	Copy constructor (copy semantics). More...

virtual	~File ()

File &	operator= (const File &that)
	Assignment (copy semantics). More...

const Path &	path () const
	Returns the pathname of the file. More...

Bool	isRegular (Bool followSymLink=True) const
	Check if the file is a regular file. More...

Bool	isDirectory (Bool followSymLink=True) const
	Check if the file is a directory. More...

Bool	isSymLink () const
	Check if the file is a symbolic link. More...

Bool	isPipe () const
	Check if the file is a pipe. More...

Bool	isCharacterSpecial () const
	Check if the file is a character special file. More...

Bool	isBlockSpecial () const
	Check if the file is a block special file. More...

Bool	isSocket () const
	Check if the file is a socket. More...

Bool	exists () const
	Check if the file exists. More...

Bool	isReadable () const
	Check if the file is readable. More...

Bool	isWritable () const
	Check if the file is writable. More...

Bool	isExecutable () const
	Check if the file is executable. More...

Bool	canCreate () const
	Check if a file can be created. More...

long	userID () const
	Return the userID of the file. More...

long	groupID () const
	Return the groupID of the file. More...

virtual Int64	size () const
	Return the size of the file. More...

uInt	readPermissions () const
	Return the permissions as a decimal value. More...

void	setPermissions (uInt permissions)
	Set permission with perm. More...

void	touch (uInt time)
	Update access time and modification time of a file. More...

void	touch ()
	Update access time and modification time of a file. More...

uInt	accessTime () const
	Time related fucnctions: Return the time when the file was last accessed in seconds since 00:00:00 GMT Jan 1, 1970. More...

String	accessTimeString () const
	Return the time when the file was last accessed as a 26-characters String of the form: Thu Feb 3 13:40:11 1994. More...

uInt	modifyTime () const
	Return the time when the file was last modified in seconds since 00:00:00 GMT Jan 1, 1970. More...

String	modifyTimeString () const
	Return the time when the file was last modified as a 26-characters String of the form: Thu Feb 3 13:40:11 1994. More...

uInt	statusChangeTime () const
	Return the time when the file status was last changed in seconds since 00:00:00 GMT Jan 1, 1970. More...

String	statusChangeTimeString () const
	return the time when the file status was last changed as a 26-characters String of the form: Thu Feb 3 13:40:11 1994 More...

FileWriteStatus	getWriteStatus () const
	get write status of the file. More...

String	getFSType () const
	Return the filesystem type. More...

Private Member Functions
void	checkPath () const
	Check if the path of the file is valid. More...

String	getSymLink () const
	Get the value of the symlink. More...

Additional Inherited Members
Public Types inherited from casacore::File
enum	FileWriteStatus { OVERWRITABLE, NOT_OVERWRITABLE, CREATABLE, NOT_CREATABLE }

Static Public Member Functions inherited from casacore::File
static Path	newUniqueName (const String &directory, const String &prefix)
	Create a new unique path name in the specified directory, with the specified prefix and random trailing characters: More...

static Path	newUniqueName (const String &directory)
	Create a new unique filename without a prefix. More...

Protected Member Functions inherited from casacore::File
void	removeSymLinks ()
	This function is used by RegularFile and Directory to remove all the links which, when followed, ultimately resolve to a Directory or a RegularFile. More...

void	checkTarget (Path &targetName, Bool overwrite, Bool forDirectory=False) const
	Check if the new path for a copy or move is valid. More...

Detailed Description

Get information about, and manipulate symbolic links.

Review Status

Reviewed By:: UNKNOWN
Date Reviewed:: before2004/08/25

Intended use:

Public interface

Prerequisite

Basic knowledge of the UNIX file system
File

Etymology

The class SymLink handles SYMbolic LINKs in the file system.

Synopsis

SymLink provides functions to manipulate and to get information about symbolic links. The functions for getting information (like ownership, dates) about symbolic links are inherited from the File class.
The class SymLink itself provides functions to create, remove, copy, and move symbolic links. There is a function readSymLink which reads a link and then returns a path and there is a function followSymLink which reads a link recursively. If the link eventually refers to itself (a loop), an exception will be thrown.

Example

SymLink symLink1("isLink");
SymLink symLink2("isLink2");
SymLink symLinkA("A");
SymLink symLinkB("B");
symLink1.create("~", True);    // Create a symbolic link to the home
// directory. When it exists it will be
// overwritten.
symLink2.create("isLink", False); // Create a symbolic link to 
// isLink. When it exists it will not
// be overwritten.
symLinkA.create(Path("B"));    // Create a recursive link
symLinkB.create(Path("A"));    // Create a recursive link
cout << symLink1.readSymLink() << endl;  // The homedirectory is printed
cout << symLink2.readSymLink() << endl;  // isLink is printed
cout << symLink2.followSymLink() << endl;// The homedirectory is printed
cout << symLinkA.readSymLink() << endl;  // B is printed
cout << symLinkA.followSymLink() << endl;// An exception is thrown (loop)

Motivation

Provide functions for manipulating and getting information about symbolic links.

Definition at line 100 of file SymLink.h.

Constructor & Destructor Documentation

casacore::SymLink::SymLink ( )

The default constructor creates a SymLink with path ".".

casacore::SymLink::SymLink ( const Path & name )

Create a SymLink with the given path.

An exception is thrown if the path exist and is no symbolic link or if it does not exist, but cannot be created.

casacore::SymLink::SymLink ( const String & name )

casacore::SymLink::SymLink ( const File & name )

casacore::SymLink::SymLink ( const SymLink & that )

Copy constructor (copy semantics).

casacore::SymLink::~SymLink ( )

Member Function Documentation

void casacore::SymLink::checkPath ( ) const

private

Check if the path of the file is valid.

Also resolve possible symlinks.

void casacore::SymLink::copy	(	const Path &	target,
		Bool	overwrite = `True`
	)		const

Copy the symlink to the target path using the system command cp.

The target path can be a directory or a file (as in cp). An exception is thrown if:
- the target directory is not writable
- or the target file already exists and overwrite==False
- or the target file already exists and is not writable

Referenced by copy().

void casacore::SymLink::copy	(	const String &	target,
		Bool	overwrite = `True`
	)		const

inline

Definition at line 192 of file SymLink.h.

References copy().

void casacore::SymLink::create	(	const Path &	target,
		Bool	overwrite = `True`
	)

Make a symbolic link to a file given by target.

An exception will be thrown if:
-target already exists and is no symlink
-or target already exists and overwrite==False

Referenced by create().

void casacore::SymLink::create	(	const String &	target,
		Bool	overwrite = `True`
	)

inline

Definition at line 188 of file SymLink.h.

References create().

Path casacore::SymLink::followSymLink ( ) const

As readSymLink, but the entire symlink chain is followed when the symlinks points to other symlinks.

An exception is thrown if this results in a loop (that is, if more than 25 links are encountered).

String casacore::SymLink::getSymLink ( ) const

private

Get the value of the symlink.

void casacore::SymLink::move	(	const Path &	target,
		Bool	overwrite = `True`
	)

Move the symlink to the target path using the system command mv.

The target path can be a directory or a file (as in mv). An exception is thrown if:
- the target directory is not writable
- or the target file already exists and overwrite==False
- or the target file already exists and is not writable

Referenced by move().

void casacore::SymLink::move	(	const String &	target,
		Bool	overwrite = `True`
	)

inline

Definition at line 196 of file SymLink.h.

References move().

SymLink& casacore::SymLink::operator= ( const SymLink & that )

Assignment (copy semantics).

Path casacore::SymLink::readSymLink ( ) const

Read value of a symbolic link and return it as a Path.

If the symlink does not exist, an exception will be thrown. When the symlink points to a file with a relative name, the resulting file name gets prepended by the dirname of the symlink, which is similar to the way a shell handles symlinks. E.g.

ls > subdir/a
ln -s a subdir/b
more subdir/b

The more command shows the results of subdir/a.

void casacore::SymLink::remove ( )

Remove a symbolic link.

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

casa/OS/SymLink.h

Public Member Functions

Private Member Functions

Additional Inherited Members

Detailed Description

Review Status

Intended use:

Prerequisite

Etymology

Synopsis

Example

Motivation

Constructor & Destructor Documentation

Member Function Documentation