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SymLink.h
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//# SymLink.h: Get information about, and manipulate symbolic links
//# Copyright (C) 1996
//# Associated Universities, Inc. Washington DC, USA.
//#
//# This library is free software; you can redistribute it and/or modify it
//# under the terms of the GNU Library General Public License as published by
//# the Free Software Foundation; either version 2 of the License, or (at your
//# option) any later version.
//#
//# This library is distributed in the hope that it will be useful, but WITHOUT
//# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
//# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
//# License for more details.
//#
//# You should have received a copy of the GNU Library General Public License
//# along with this library; if not, write to the Free Software Foundation,
//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
//#
//# Correspondence concerning AIPS++ should be addressed as follows:
//# Internet email: casa-feedback@nrao.edu.
//# Postal address: AIPS++ Project Office
//# National Radio Astronomy Observatory
//# 520 Edgemont Road
//# Charlottesville, VA 22903-2475 USA
#ifndef CASA_SYMLINK_H
#define CASA_SYMLINK_H
//# Includes
#include <casacore/casa/aips.h>
#include <casacore/casa/OS/Path.h>
#include <casacore/casa/OS/File.h>
namespace casacore { //# NAMESPACE CASACORE - BEGIN
// <summary>
// Get information about, and manipulate symbolic links
// </summary>
// <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="" demos="">
// </reviewed>
// <use visibility=export>
// <prerequisite>
// <li> Basic knowledge of the UNIX file system
// <li> <linkto class=File>File</linkto>
// </prerequisite>
// <etymology>
// The class SymLink handles SYMbolic LINKs in the file system.
// </etymology>
// <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
// <linkto class=File>File</linkto> class.
// <br>
// 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.
// </synopsis>
// <example>
// <srcblock>
// 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)
// </srcblock>
// </example>
// <motivation>
// Provide functions for manipulating and getting information
// about symbolic links.
// </motivation>
class SymLink: public File
{
public:
// The default constructor creates a SymLink with path ".".
SymLink();
// 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.
// <group>
SymLink (const Path& name);
SymLink (const String& name);
SymLink (const File& name);
// </group>
// Copy constructor (copy semantics).
SymLink (const SymLink& that);
~SymLink();
// Assignment (copy semantics).
SymLink& operator= (const SymLink& that);
// Make a symbolic link to a file given by target.
// An exception will be thrown if:
// <br>-target already exists and is no symlink
// <br>-or target already exists and overwrite==False
// <group>
void create (const Path& target, Bool overwrite = True);
void create (const String& target, Bool overwrite = True);
// </group>
// 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:
// <br>- the target directory is not writable
// <br>- or the target file already exists and overwrite==False
// <br>- or the target file already exists and is not writable
// <group>
void copy (const Path& target, Bool overwrite = True) const;
void copy (const String& target, Bool overwrite = True) const;
// </group>
// 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:
// <br>- the target directory is not writable
// <br>- or the target file already exists and overwrite==False
// <br>- or the target file already exists and is not writable
// <group>
void move (const Path& target, Bool overwrite = True);
void move (const String& target, Bool overwrite = True);
// </group>
// Remove a symbolic link.
void remove();
// 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.
// <srcblock>
// ls > subdir/a
// ln -s a subdir/b
// more subdir/b
// </srcblock>
// The more command shows the results of subdir/a.
Path readSymLink() 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).
Path followSymLink() const;
private:
// Check if the path of the file is valid.
// Also resolve possible symlinks.
void checkPath() const;
// Get the value of the symlink.
String getSymLink() const;
};
inline void SymLink::create (const String& target, Bool overwrite)
{
create (Path(target), overwrite);
}
inline void SymLink::copy (const String& target, Bool overwrite) const
{
copy (Path(target), overwrite);
}
inline void SymLink::move (const String& target, Bool overwrite)
{
move (Path(target), overwrite);
}
} //# NAMESPACE CASACORE - END
#endif
casacore::File::File
File()
Construct a File object whose Path is set to the current working directory.
casacore::Path
Definition Path.h:124
casacore::String
String: the storage and methods of handling collections of characters.
Definition String.h:223
casacore::SymLink::~SymLink
~SymLink()
casacore::SymLink::getSymLink
String getSymLink() const
Get the value of the symlink.
casacore::SymLink::create
void create(const Path &target, Bool overwrite=True)
Make a symbolic link to a file given by target.
casacore::SymLink::remove
void remove()
Remove a symbolic link.
casacore::SymLink::SymLink
SymLink(const Path &name)
Create a SymLink with the given path.
casacore::SymLink::SymLink
SymLink(const SymLink &that)
Copy constructor (copy semantics).
casacore::SymLink::copy
void copy(const Path &target, Bool overwrite=True) const
Copy the symlink to the target path using the system command cp.
casacore::SymLink::SymLink
SymLink(const File &name)
casacore::SymLink::SymLink
SymLink()
The default constructor creates a SymLink with path ".".
casacore::SymLink::checkPath
void checkPath() const
Check if the path of the file is valid.
casacore::SymLink::readSymLink
Path readSymLink() const
Read value of a symbolic link and return it as a Path.
casacore::SymLink::operator=
SymLink & operator=(const SymLink &that)
Assignment (copy semantics).
casacore::SymLink::move
void move(const Path &target, Bool overwrite=True)
Move the symlink to the target path using the system command mv.
casacore::SymLink::SymLink
SymLink(const String &name)
casacore::SymLink::followSymLink
Path followSymLink() const
As readSymLink, but the entire symlink chain is followed when the symlinks points to other symlinks.
casacore
this file contains all the compiler specific defines
Definition mainpage.dox:28
casacore::name
String name() const
Return the name of the field.
Definition RecordField.h:163
casacore::Bool
bool Bool
Define the standard types used by Casacore.
Definition aipstype.h:40
casacore::True
const Bool True
Definition aipstype.h:41