/IronPython_Main/Runtime/Tests/LinqDlrTests/testenv/perl/lib/Cwd.pm

package Cwd;

require 5.000;



=head1 NAME



Cwd - get pathname of current working directory



=head1 SYNOPSIS



    use Cwd;

    $dir = cwd;



    use Cwd;

    $dir = getcwd;



    use Cwd;

    $dir = fastcwd;



    use Cwd;

    $dir = fastgetcwd;



    use Cwd 'chdir';

    chdir "/tmp";

    print $ENV{'PWD'};



    use Cwd 'abs_path';	    # aka realpath()

    print abs_path($ENV{'PWD'});



    use Cwd 'fast_abs_path';

    print fast_abs_path($ENV{'PWD'});



=head1 DESCRIPTION



This module provides functions for determining the pathname of the

current working directory.  By default, it exports the functions

cwd(), getcwd(), fastcwd(), and fastgetcwd() into the caller's

namespace.  Each of these functions are called without arguments and

return the absolute path of the current working directory.  It is

recommended that cwd (or another *cwd() function) be used in I<all>

code to ensure portability.



The cwd() is the most natural and safe form for the current

architecture. For most systems it is identical to `pwd` (but without

the trailing line terminator).



The getcwd() function re-implements the getcwd(3) (or getwd(3)) functions

in Perl.



The fastcwd() function looks the same as getcwd(), but runs faster.

It's also more dangerous because it might conceivably chdir() you out

of a directory that it can't chdir() you back into.  If fastcwd

encounters a problem it will return undef but will probably leave you

in a different directory.  For a measure of extra security, if

everything appears to have worked, the fastcwd() function will check

that it leaves you in the same directory that it started in. If it has

changed it will C<die> with the message "Unstable directory path,

current directory changed unexpectedly". That should never happen.



The fastgetcwd() function is provided as a synonym for cwd().



The abs_path() function takes a single argument and returns the

absolute pathname for that argument.  It uses the same algorithm as

getcwd().  (Actually, getcwd() is abs_path("."))  Symbolic links and

relative-path components ("." and "..") are resolved to return the

canonical pathname, just like realpath(3).  This function is also

callable as realpath().



The fast_abs_path() function looks the same as abs_path() but runs

faster and, like fastcwd(), is more dangerous.



If you ask to override your chdir() built-in function, then your PWD

environment variable will be kept up to date.  (See

L<perlsub/Overriding Builtin Functions>.) Note that it will only be

kept up to date if all packages which use chdir import it from Cwd.



=cut



use strict;



use Carp;



our $VERSION = '2.04';



use base qw/ Exporter /;

our @EXPORT = qw(cwd getcwd fastcwd fastgetcwd);

our @EXPORT_OK = qw(chdir abs_path fast_abs_path realpath fast_realpath);





# The 'natural and safe form' for UNIX (pwd may be setuid root)



sub _backtick_pwd {

    my $cwd = `pwd`;

    # `pwd` may fail e.g. if the disk is full

    chomp($cwd) if defined $cwd;

    $cwd;

}



# Since some ports may predefine cwd internally (e.g., NT)

# we take care not to override an existing definition for cwd().



unless(defined &cwd) {

    # The pwd command is not available in some chroot(2)'ed environments

    if($^O eq 'MacOS' || grep { -x "$_/pwd" } split(':', $ENV{PATH})) {

	*cwd = \&_backtick_pwd;

    }

    else {

	*cwd = \&getcwd;

    }

}



# set a reasonable (and very safe) default for fastgetcwd, in case it

# isn't redefined later (20001212 rspier)

*fastgetcwd = \&cwd;



# By Brandon S. Allbery

#

# Usage: $cwd = getcwd();



sub getcwd

{

    abs_path('.');

}



# By John Bazik

#

# Usage: $cwd = &fastcwd;

#

# This is a faster version of getcwd.  It's also more dangerous because

# you might chdir out of a directory that you can't chdir back into.

    

sub fastcwd {

    my($odev, $oino, $cdev, $cino, $tdev, $tino);

    my(@path, $path);

    local(*DIR);



    my($orig_cdev, $orig_cino) = stat('.');

    ($cdev, $cino) = ($orig_cdev, $orig_cino);

    for (;;) {

	my $direntry;

	($odev, $oino) = ($cdev, $cino);

	CORE::chdir('..') || return undef;

	($cdev, $cino) = stat('.');

	last if $odev == $cdev && $oino == $cino;

	opendir(DIR, '.') || return undef;

	for (;;) {

	    $direntry = readdir(DIR);

	    last unless defined $direntry;

	    next if $direntry eq '.';

	    next if $direntry eq '..';



	    ($tdev, $tino) = lstat($direntry);

	    last unless $tdev != $odev || $tino != $oino;

	}

	closedir(DIR);

	return undef unless defined $direntry; # should never happen

	unshift(@path, $direntry);

    }

    $path = '/' . join('/', @path);

    if ($^O eq 'apollo') { $path = "/".$path; }

    # At this point $path may be tainted (if tainting) and chdir would fail.

    # To be more useful we untaint it then check that we landed where we started.

    $path = $1 if $path =~ /^(.*)\z/s;	# untaint

    CORE::chdir($path) || return undef;

    ($cdev, $cino) = stat('.');

    die "Unstable directory path, current directory changed unexpectedly"

	if $cdev != $orig_cdev || $cino != $orig_cino;

    $path;

}





# Keeps track of current working directory in PWD environment var

# Usage:

#	use Cwd 'chdir';

#	chdir $newdir;



my $chdir_init = 0;



sub chdir_init {

    if ($ENV{'PWD'} and $^O ne 'os2' and $^O ne 'dos' and $^O ne 'MSWin32') {

	my($dd,$di) = stat('.');

	my($pd,$pi) = stat($ENV{'PWD'});

	if (!defined $dd or !defined $pd or $di != $pi or $dd != $pd) {

	    $ENV{'PWD'} = cwd();

	}

    }

    else {

	my $wd = cwd();

	$wd = Win32::GetFullPathName($wd) if $^O eq 'MSWin32';

	$ENV{'PWD'} = $wd;

    }

    # Strip an automounter prefix (where /tmp_mnt/foo/bar == /foo/bar)

    if ($^O ne 'MSWin32' and $ENV{'PWD'} =~ m|(/[^/]+(/[^/]+/[^/]+))(.*)|s) {

	my($pd,$pi) = stat($2);

	my($dd,$di) = stat($1);

	if (defined $pd and defined $dd and $di == $pi and $dd == $pd) {

	    $ENV{'PWD'}="$2$3";

	}

    }

    $chdir_init = 1;

}



sub chdir {

    my $newdir = @_ ? shift : '';	# allow for no arg (chdir to HOME dir)

    $newdir =~ s|///*|/|g unless $^O eq 'MSWin32';

    chdir_init() unless $chdir_init;

    my $newpwd;

    if ($^O eq 'MSWin32') {

	# get the full path name *before* the chdir()

	$newpwd = Win32::GetFullPathName($newdir);

    }



    return 0 unless CORE::chdir $newdir;



    if ($^O eq 'VMS') {

	return $ENV{'PWD'} = $ENV{'DEFAULT'}

    }

    elsif ($^O eq 'MacOS') {

	return $ENV{'PWD'} = cwd();

    }

    elsif ($^O eq 'MSWin32') {

	$ENV{'PWD'} = $newpwd;

	return 1;

    }



    if ($newdir =~ m#^/#s) {

	$ENV{'PWD'} = $newdir;

    } else {

	my @curdir = split(m#/#,$ENV{'PWD'});

	@curdir = ('') unless @curdir;

	my $component;

	foreach $component (split(m#/#, $newdir)) {

	    next if $component eq '.';

	    pop(@curdir),next if $component eq '..';

	    push(@curdir,$component);

	}

	$ENV{'PWD'} = join('/',@curdir) || '/';

    }

    1;

}



# Taken from Cwd.pm It is really getcwd with an optional

# parameter instead of '.'

#



sub abs_path

{

    my $start = @_ ? shift : '.';

    my($dotdots, $cwd, @pst, @cst, $dir, @tst);



    unless (@cst = stat( $start ))

    {

	carp "stat($start): $!";

	return '';

    }

    $cwd = '';

    $dotdots = $start;

    do

    {

	$dotdots .= '/..';

	@pst = @cst;

	unless (opendir(PARENT, $dotdots))

	{

	    carp "opendir($dotdots): $!";

	    return '';

	}

	unless (@cst = stat($dotdots))

	{

	    carp "stat($dotdots): $!";

	    closedir(PARENT);

	    return '';

	}

	if ($pst[0] == $cst[0] && $pst[1] == $cst[1])

	{

	    $dir = undef;

	}

	else

	{

	    do

	    {

		unless (defined ($dir = readdir(PARENT)))

	        {

		    carp "readdir($dotdots): $!";

		    closedir(PARENT);

		    return '';

		}

		$tst[0] = $pst[0]+1 unless (@tst = lstat("$dotdots/$dir"))

	    }

	    while ($dir eq '.' || $dir eq '..' || $tst[0] != $pst[0] ||

		   $tst[1] != $pst[1]);

	}

	$cwd = (defined $dir ? "$dir" : "" ) . "/$cwd" ;

	closedir(PARENT);

    } while (defined $dir);

    chop($cwd) unless $cwd eq '/'; # drop the trailing /

    $cwd;

}



# added function alias for those of us more

# used to the libc function.  --tchrist 27-Jan-00

*realpath = \&abs_path;



sub fast_abs_path {

    my $cwd = getcwd();

    my $path = @_ ? shift : '.';

    CORE::chdir($path) || croak "Cannot chdir to $path:$!";

    my $realpath = getcwd();

    CORE::chdir($cwd)  || croak "Cannot chdir back to $cwd:$!";

    $realpath;

}



# added function alias to follow principle of least surprise

# based on previous aliasing.  --tchrist 27-Jan-00

*fast_realpath = \&fast_abs_path;





# --- PORTING SECTION ---



# VMS: $ENV{'DEFAULT'} points to default directory at all times

# 06-Mar-1996  Charles Bailey  bailey@newman.upenn.edu

# Note: Use of Cwd::chdir() causes the logical name PWD to be defined

#   in the process logical name table as the default device and directory

#   seen by Perl. This may not be the same as the default device

#   and directory seen by DCL after Perl exits, since the effects

#   the CRTL chdir() function persist only until Perl exits.



sub _vms_cwd {

    return $ENV{'DEFAULT'};

}



sub _vms_abs_path {

    return $ENV{'DEFAULT'} unless @_;

    my $path = VMS::Filespec::pathify($_[0]);

    croak("Invalid path name $_[0]") unless defined $path;

    return VMS::Filespec::rmsexpand($path);

}



sub _os2_cwd {

    $ENV{'PWD'} = `cmd /c cd`;

    chop $ENV{'PWD'};

    $ENV{'PWD'} =~ s:\\:/:g ;

    return $ENV{'PWD'};

}



sub _win32_cwd {

    $ENV{'PWD'} = Win32::GetCwd();

    $ENV{'PWD'} =~ s:\\:/:g ;

    return $ENV{'PWD'};

}



*_NT_cwd = \&_win32_cwd if (!defined &_NT_cwd && 

                            defined &Win32::GetCwd);



*_NT_cwd = \&_os2_cwd unless defined &_NT_cwd;



sub _dos_cwd {

    if (!defined &Dos::GetCwd) {

        $ENV{'PWD'} = `command /c cd`;

        chop $ENV{'PWD'};

        $ENV{'PWD'} =~ s:\\:/:g ;

    } else {

        $ENV{'PWD'} = Dos::GetCwd();

    }

    return $ENV{'PWD'};

}



sub _qnx_cwd {

    $ENV{'PWD'} = `/usr/bin/fullpath -t`;

    chop $ENV{'PWD'};

    return $ENV{'PWD'};

}



sub _qnx_abs_path {

    my $path = @_ ? shift : '.';

    my $realpath=`/usr/bin/fullpath -t $path`;

    chop $realpath;

    return $realpath;

}



sub _epoc_cwd {

    $ENV{'PWD'} = EPOC::getcwd();

    return $ENV{'PWD'};

}



{

    no warnings;	# assignments trigger 'subroutine redefined' warning



    if ($^O eq 'VMS') {

        *cwd		= \&_vms_cwd;

        *getcwd		= \&_vms_cwd;

        *fastcwd	= \&_vms_cwd;

        *fastgetcwd	= \&_vms_cwd;

        *abs_path	= \&_vms_abs_path;

        *fast_abs_path	= \&_vms_abs_path;

    }

    elsif ($^O eq 'NT' or $^O eq 'MSWin32') {

        # We assume that &_NT_cwd is defined as an XSUB or in the core.

        *cwd		= \&_NT_cwd;

        *getcwd		= \&_NT_cwd;

        *fastcwd	= \&_NT_cwd;

        *fastgetcwd	= \&_NT_cwd;

        *abs_path	= \&fast_abs_path;

    }

    elsif ($^O eq 'os2') {

        # sys_cwd may keep the builtin command

        *cwd		= defined &sys_cwd ? \&sys_cwd : \&_os2_cwd;

        *getcwd		= \&cwd;

        *fastgetcwd	= \&cwd;

        *fastcwd	= \&cwd;

        *abs_path	= \&fast_abs_path;

    }

    elsif ($^O eq 'dos') {

        *cwd		= \&_dos_cwd;

        *getcwd		= \&_dos_cwd;

        *fastgetcwd	= \&_dos_cwd;

        *fastcwd	= \&_dos_cwd;

        *abs_path	= \&fast_abs_path;

    }

    elsif ($^O eq 'qnx') {

        *cwd		= \&_qnx_cwd;

        *getcwd		= \&_qnx_cwd;

        *fastgetcwd	= \&_qnx_cwd;

        *fastcwd	= \&_qnx_cwd;

        *abs_path	= \&_qnx_abs_path;

        *fast_abs_path	= \&_qnx_abs_path;

    }

    elsif ($^O eq 'cygwin') {

        *getcwd	= \&cwd;

        *fastgetcwd	= \&cwd;

        *fastcwd	= \&cwd;

        *abs_path	= \&fast_abs_path;

    }

    elsif ($^O eq 'epoc') {

        *cwd            = \&_epoc_cwd;

        *getcwd	        = \&_epoc_cwd;

        *fastgetcwd	= \&_epoc_cwd;

        *fastcwd	= \&_epoc_cwd;

        *abs_path	= \&fast_abs_path;

    }

    elsif ($^O eq 'MacOS') {

    	*getcwd     = \&cwd;

    	*fastgetcwd = \&cwd;

    	*fastcwd    = \&cwd;

    	*abs_path   = \&fast_abs_path;

    }

}



# package main; eval join('',<DATA>) || die $@;	# quick test



1;



__END__

BEGIN { import Cwd qw(:DEFAULT chdir); }

print join("\n", cwd, getcwd, fastcwd, "");

chdir('..');

print join("\n", cwd, getcwd, fastcwd, "");

print "$ENV{PWD}\n";