[p5sagit/p5-mst-13.2.git] / lib / Cwd.pm

package Cwd;
require 5.6.0;

=head1 NAME

Cwd - get pathname of current working directory

=head1 SYNOPSIS

    use Cwd;
    my $dir = getcwd;

    use Cwd 'abs_path';
    my $abs_path = abs_path($file);

=head1 DESCRIPTION

This module provides functions for determining the pathname of the
current working directory.  It is recommended that getcwd (or another
*cwd() function) be used in I<all> code to ensure portability.

By default, it exports the functions cwd(), getcwd(), fastcwd(), and
fastgetcwd() into the caller's namespace.  


=head2 getcwd and friends

Each of these functions are called without arguments and return the
absolute path of the current working directory.

=over 4

=item getcwd

    my $cwd = getcwd();

Returns the current working directory.

Re-implements the getcwd(3) (or getwd(3)) functions in Perl.

=item cwd

    my $cwd = cwd();

The cwd() is the most natural form for the current architecture. For
most systems it is identical to `pwd` (but without the trailing line
terminator).

Unfortunately, cwd() tends to break if called under taint mode.

=item fastcwd

    my $cwd = fastcwd();

A more dangerous version of getcwd(), but potentially faster.

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.

=item fastgetcwd

  my $cwd = fastgetcwd();

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

=back


=head2 abs_path and friends

These functions are exported only on request.  They each take a single
argument and return the absolute pathname for it.

=over 4

=item abs_path

  my $abs_path = abs_path($file);

Uses the same algorithm as getcwd().  Symbolic links and relative-path
components ("." and "..") are resolved to return the canonical
pathname, just like realpath(3).

=item realpath

  my $abs_path = realpath($file);

A synonym for abs_path().

=item fast_abs_path

  my $abs_path = abs_path($file);

A more dangerous, but potentially faster version of abs_path.

=back

=head2 $ENV{PWD}

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

  use Cwd qw(chdir);

then your PWD environment variable will be kept up to date.  Note that
it will only be kept up to date if all packages which use chdir import
it from Cwd.


=head1 NOTES

=over 4

=item *

Since the path seperators are different on some operating systems ('/'
on Unix, ':' on MacPerl, etc...) we recommend you use the File::Spec
modules wherever portability is a concern.

=begin _private

=item *

Actually, on Mac OS, the C<getcwd()>, C<fastgetcwd()> and C<fastcwd()>
functions  are all aliases for the C<cwd()> function, which, on Mac OS,
calls `pwd`. Likewise, the C<abs_path()> function is an alias for
C<fast_abs_path()>.

=end _private

=back

=head1 SEE ALSO

L<File::chdir>

=cut

use strict;

use Carp;

our $VERSION = '2.06';

use base qw/ Exporter /;
our @EXPORT = qw(cwd getcwd fastcwd fastgetcwd);
our @EXPORT_OK = qw(chdir abs_path fast_abs_path realpath fast_realpath);

# sys_cwd may keep the builtin command

# All the functionality of this module may provided by builtins,
# there is no sense to process the rest of the file.
# The best choice may be to have this in BEGIN, but how to return from BEGIN?

if ($^O eq 'os2' && defined &sys_cwd && defined &sys_abspath) {
    local $^W = 0;
    *cwd		= \&sys_cwd;
    *getcwd		= \&cwd;
    *fastgetcwd		= \&cwd;
    *fastcwd		= \&cwd;
    *abs_path		= \&sys_abspath;
    *fast_abs_path	= \&abs_path;
    *realpath		= \&abs_path;
    *fast_realpath	= \&abs_path;
    return 1;
}

eval {
    require XSLoader;
    XSLoader::load('Cwd');
};


# Find the pwd command in the expected locations.  We assume these
# are safe.  This prevents _backtick_pwd() consulting $ENV{PATH}
# so everything works under taint mode.
my $pwd_cmd;
foreach my $try (qw(/bin/pwd /usr/bin/pwd)) {
    if( -x $try ) {
        $pwd_cmd = $try;
        last;
    }
}
$pwd_cmd ||= 'pwd';

# The 'natural and safe form' for UNIX (pwd may be setuid root)
sub _backtick_pwd {
    my $cwd = `$pwd_cmd`;
    # `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('.');
}

# 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;
}

# 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();
    require File::Spec;
    my $path = @_ ? shift : File::Spec->curdir;
    CORE::chdir($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 =~ m/^(?:qnx|nto)$/ ) {
        *cwd		= \&_qnx_cwd;
        *getcwd		= \&_qnx_cwd;
        *fastgetcwd	= \&_qnx_cwd;
        *fastcwd	= \&_qnx_cwd;
        *abs_path	= \&_qnx_abs_path;
        *fast_abs_path	= \&_qnx_abs_path;
    }
    elsif ($^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";
Commit	Line	Data
a0d0e21e	1	package Cwd;
4d6b4052	2	require 5.6.0;
a0d0e21e	3
f06db76b	4	=head1 NAME
f06db76b	5
902bacac	6	Cwd - get pathname of current working directory
f06db76b	7
	8	=head1 SYNOPSIS
	9
4633a7c4	10	use Cwd;
04929354	11	my $dir = getcwd;
4633a7c4	12
04929354	13	use Cwd 'abs_path';
04929354	14	my $abs_path = abs_path($file);
f06db76b	15
04929354	16	=head1 DESCRIPTION
902bacac	17
04929354	18	This module provides functions for determining the pathname of the
	19	current working directory. It is recommended that getcwd (or another
	20	*cwd() function) be used in I<all> code to ensure portability.
f06db76b	21
04929354	22	By default, it exports the functions cwd(), getcwd(), fastcwd(), and
04929354	23	fastgetcwd() into the caller's namespace.
f06db76b	24
20408e3c	25
04929354	26	=head2 getcwd and friends
20408e3c	27
04929354	28	Each of these functions are called without arguments and return the
04929354	29	absolute path of the current working directory.
f06db76b	30
04929354	31	=over 4
	32
	33	=item getcwd
	34
	35	my $cwd = getcwd();
	36
	37	Returns the current working directory.
	38
	39	Re-implements the getcwd(3) (or getwd(3)) functions in Perl.
	40
	41	=item cwd
	42
	43	my $cwd = cwd();
	44
	45	The cwd() is the most natural form for the current architecture. For
	46	most systems it is identical to `pwd` (but without the trailing line
	47	terminator).
	48
	49	Unfortunately, cwd() tends to break if called under taint mode.
	50
	51	=item fastcwd
	52
	53	my $cwd = fastcwd();
	54
	55	A more dangerous version of getcwd(), but potentially faster.
	56
	57	It might conceivably chdir() you out of a directory that it can't
	58	chdir() you back into. If fastcwd encounters a problem it will return
	59	undef but will probably leave you in a different directory. For a
	60	measure of extra security, if everything appears to have worked, the
	61	fastcwd() function will check that it leaves you in the same directory
	62	that it started in. If it has changed it will C<die> with the message
	63	"Unstable directory path, current directory changed
	64	unexpectedly". That should never happen.
	65
	66	=item fastgetcwd
	67
	68	my $cwd = fastgetcwd();
f06db76b	69
902bacac	70	The fastgetcwd() function is provided as a synonym for cwd().
fb73857a	71
04929354	72	=back
04929354	73
902bacac	74
04929354	75	=head2 abs_path and friends
	76
	77	These functions are exported only on request. They each take a single
	78	argument and return the absolute pathname for it.
	79
	80	=over 4
	81
	82	=item abs_path
	83
	84	my $abs_path = abs_path($file);
	85
	86	Uses the same algorithm as getcwd(). Symbolic links and relative-path
	87	components ("." and "..") are resolved to return the canonical
	88	pathname, just like realpath(3).
	89
	90	=item realpath
	91
	92	my $abs_path = realpath($file);
	93
	94	A synonym for abs_path().
	95
	96	=item fast_abs_path
	97
	98	my $abs_path = abs_path($file);
	99
	100	A more dangerous, but potentially faster version of abs_path.
	101
	102	=back
	103
	104	=head2 $ENV{PWD}
	105
	106	If you ask to override your chdir() built-in function,
	107
	108	use Cwd qw(chdir);
	109
	110	then your PWD environment variable will be kept up to date. Note that
	111	it will only be kept up to date if all packages which use chdir import
	112	it from Cwd.
4633a7c4	113
4633a7c4	114
4d6b4052	115	=head1 NOTES
	116
	117	=over 4
	118
	119	=item *
	120
04929354	121	Since the path seperators are different on some operating systems ('/'
	122	on Unix, ':' on MacPerl, etc...) we recommend you use the File::Spec
	123	modules wherever portability is a concern.
	124
	125	=begin _private
	126
	127	=item *
4d6b4052	128
	129	Actually, on Mac OS, the C<getcwd()>, C<fastgetcwd()> and C<fastcwd()>
	130	functions are all aliases for the C<cwd()> function, which, on Mac OS,
	131	calls `pwd`. Likewise, the C<abs_path()> function is an alias for
	132	C<fast_abs_path()>.
	133
04929354	134	=end _private
04929354	135
4d6b4052	136	=back
4d6b4052	137
04929354	138	=head1 SEE ALSO
	139
	140	L<File::chdir>
	141
f06db76b	142	=cut
f06db76b	143
b060a406	144	use strict;
96e4d5b1	145
	146	use Carp;
	147
04929354	148	our $VERSION = '2.06';
96e4d5b1	149
b060a406	150	use base qw/ Exporter /;
	151	our @EXPORT = qw(cwd getcwd fastcwd fastgetcwd);
	152	our @EXPORT_OK = qw(chdir abs_path fast_abs_path realpath fast_realpath);
a0d0e21e	153
f5f423e4	154	# sys_cwd may keep the builtin command
	155
	156	# All the functionality of this module may provided by builtins,
	157	# there is no sense to process the rest of the file.
	158	# The best choice may be to have this in BEGIN, but how to return from BEGIN?
	159
	160	if ($^O eq 'os2' && defined &sys_cwd && defined &sys_abspath) {
	161	local $^W = 0;
	162	*cwd = \&sys_cwd;
	163	*getcwd = \&cwd;
	164	*fastgetcwd = \&cwd;
	165	*fastcwd = \&cwd;
	166	*abs_path = \&sys_abspath;
	167	*fast_abs_path = \&abs_path;
	168	*realpath = \&abs_path;
	169	*fast_realpath = \&abs_path;
	170	return 1;
	171	}
	172
f22d8e4b	173	eval {
	174	require XSLoader;
	175	XSLoader::load('Cwd');
	176	};
4633a7c4	177
96e4d5b1	178
3547aa9a	179	# Find the pwd command in the expected locations. We assume these
	180	# are safe. This prevents _backtick_pwd() consulting $ENV{PATH}
	181	# so everything works under taint mode.
	182	my $pwd_cmd;
	183	foreach my $try (qw(/bin/pwd /usr/bin/pwd)) {
	184	if( -x $try ) {
	185	$pwd_cmd = $try;
	186	last;
	187	}
	188	}
	189	$pwd_cmd \|\|= 'pwd';
	190
	191	# The 'natural and safe form' for UNIX (pwd may be setuid root)
8b88ae92	192	sub _backtick_pwd {
3547aa9a	193	my $cwd = `$pwd_cmd`;
7e03f963	194	# `pwd` may fail e.g. if the disk is full
7e03f963	195	chomp($cwd) if defined $cwd;
4633a7c4	196	$cwd;
8b88ae92	197	}
4633a7c4	198
	199	# Since some ports may predefine cwd internally (e.g., NT)
	200	# we take care not to override an existing definition for cwd().
	201
ea54c8bd	202	unless(defined &cwd) {
ea54c8bd	203	# The pwd command is not available in some chroot(2)'ed environments
4aecb5b5	204	if($^O eq 'MacOS' \|\| grep { -x "$_/pwd" } split(':', $ENV{PATH})) {
ea54c8bd	205	*cwd = \&_backtick_pwd;
	206	}
	207	else {
	208	*cwd = \&getcwd;
	209	}
	210	}
a0d0e21e	211
1f4f94f5	212	# set a reasonable (and very safe) default for fastgetcwd, in case it
	213	# isn't redefined later (20001212 rspier)
	214	*fastgetcwd = \&cwd;
748a9306	215
a0d0e21e	216	# By Brandon S. Allbery
	217	#
	218	# Usage: $cwd = getcwd();
	219
	220	sub getcwd
	221	{
07569ed3	222	abs_path('.');
a0d0e21e	223	}
a0d0e21e	224
4633a7c4	225	# Keeps track of current working directory in PWD environment var
a0d0e21e	226	# Usage:
	227	# use Cwd 'chdir';
	228	# chdir $newdir;
	229
4633a7c4	230	my $chdir_init = 0;
a0d0e21e	231
4633a7c4	232	sub chdir_init {
3b8e3443	233	if ($ENV{'PWD'} and $^O ne 'os2' and $^O ne 'dos' and $^O ne 'MSWin32') {
a0d0e21e	234	my($dd,$di) = stat('.');
	235	my($pd,$pi) = stat($ENV{'PWD'});
	236	if (!defined $dd or !defined $pd or $di != $pi or $dd != $pd) {
4633a7c4	237	$ENV{'PWD'} = cwd();
a0d0e21e	238	}
	239	}
	240	else {
3b8e3443	241	my $wd = cwd();
	242	$wd = Win32::GetFullPathName($wd) if $^O eq 'MSWin32';
	243	$ENV{'PWD'} = $wd;
a0d0e21e	244	}
4633a7c4	245	# Strip an automounter prefix (where /tmp_mnt/foo/bar == /foo/bar)
3b8e3443	246	if ($^O ne 'MSWin32' and $ENV{'PWD'} =~ m\|(/[^/]+(/[^/]+/[^/]+))(.*)\|s) {
a0d0e21e	247	my($pd,$pi) = stat($2);
	248	my($dd,$di) = stat($1);
	249	if (defined $pd and defined $dd and $di == $pi and $dd == $pd) {
	250	$ENV{'PWD'}="$2$3";
	251	}
	252	}
	253	$chdir_init = 1;
	254	}
	255
	256	sub chdir {
22978713	257	my $newdir = @_ ? shift : ''; # allow for no arg (chdir to HOME dir)
3b8e3443	258	$newdir =~ s\|///*\|/\|g unless $^O eq 'MSWin32';
a0d0e21e	259	chdir_init() unless $chdir_init;
4ffa1610	260	my $newpwd;
	261	if ($^O eq 'MSWin32') {
	262	# get the full path name before the chdir()
	263	$newpwd = Win32::GetFullPathName($newdir);
	264	}
	265
4633a7c4	266	return 0 unless CORE::chdir $newdir;
4ffa1610	267
3b8e3443	268	if ($^O eq 'VMS') {
	269	return $ENV{'PWD'} = $ENV{'DEFAULT'}
	270	}
4aecb5b5	271	elsif ($^O eq 'MacOS') {
	272	return $ENV{'PWD'} = cwd();
	273	}
3b8e3443	274	elsif ($^O eq 'MSWin32') {
4ffa1610	275	$ENV{'PWD'} = $newpwd;
3b8e3443	276	return 1;
3b8e3443	277	}
748a9306	278
392d8ab8	279	if ($newdir =~ m#^/#s) {
a0d0e21e	280	$ENV{'PWD'} = $newdir;
4633a7c4	281	} else {
	282	my @curdir = split(m#/#,$ENV{'PWD'});
	283	@curdir = ('') unless @curdir;
	284	my $component;
a0d0e21e	285	foreach $component (split(m#/#, $newdir)) {
	286	next if $component eq '.';
	287	pop(@curdir),next if $component eq '..';
	288	push(@curdir,$component);
	289	}
	290	$ENV{'PWD'} = join('/',@curdir) \|\| '/';
	291	}
4633a7c4	292	1;
a0d0e21e	293	}
a0d0e21e	294
e4c51978	295	# added function alias for those of us more
	296	# used to the libc function. --tchrist 27-Jan-00
	297	*realpath = \&abs_path;
	298
96e4d5b1	299	sub fast_abs_path {
96e4d5b1	300	my $cwd = getcwd();
4d6b4052	301	require File::Spec;
4d6b4052	302	my $path = @_ ? shift : File::Spec->curdir;
e79e61e4	303	CORE::chdir($path) \|\| croak "Cannot chdir to $path:$!";
96e4d5b1	304	my $realpath = getcwd();
e79e61e4	305	CORE::chdir($cwd) \|\| croak "Cannot chdir back to $cwd:$!";
96e4d5b1	306	$realpath;
8b88ae92	307	}
8b88ae92	308
e4c51978	309	# added function alias to follow principle of least surprise
	310	# based on previous aliasing. --tchrist 27-Jan-00
	311	*fast_realpath = \&fast_abs_path;
	312
4633a7c4	313
	314	# --- PORTING SECTION ---
	315
	316	# VMS: $ENV{'DEFAULT'} points to default directory at all times
bd3fa61c	317	# 06-Mar-1996 Charles Bailey bailey@newman.upenn.edu
c6538b72	318	# Note: Use of Cwd::chdir() causes the logical name PWD to be defined
8b88ae92	319	# in the process logical name table as the default device and directory
8b88ae92	320	# seen by Perl. This may not be the same as the default device
4633a7c4	321	# and directory seen by DCL after Perl exits, since the effects
4633a7c4	322	# the CRTL chdir() function persist only until Perl exits.
4633a7c4	323
4633a7c4	324	sub _vms_cwd {
96e4d5b1	325	return $ENV{'DEFAULT'};
	326	}
	327
	328	sub _vms_abs_path {
	329	return $ENV{'DEFAULT'} unless @_;
	330	my $path = VMS::Filespec::pathify($_[0]);
	331	croak("Invalid path name $_[0]") unless defined $path;
	332	return VMS::Filespec::rmsexpand($path);
4633a7c4	333	}
68dc0745	334
4633a7c4	335	sub _os2_cwd {
	336	$ENV{'PWD'} = `cmd /c cd`;
	337	chop $ENV{'PWD'};
	338	$ENV{'PWD'} =~ s:\\:/:g ;
	339	return $ENV{'PWD'};
	340	}
	341
96e4d5b1	342	sub _win32_cwd {
2d7a9237	343	$ENV{'PWD'} = Win32::GetCwd();
96e4d5b1	344	$ENV{'PWD'} =~ s:\\:/:g ;
	345	return $ENV{'PWD'};
	346	}
	347
	348	*_NT_cwd = \&_win32_cwd if (!defined &_NT_cwd &&
2d7a9237	349	defined &Win32::GetCwd);
96e4d5b1	350
96e4d5b1	351	*_NT_cwd = \&_os2_cwd unless defined &_NT_cwd;
68dc0745	352
39e571d4	353	sub _dos_cwd {
	354	if (!defined &Dos::GetCwd) {
	355	$ENV{'PWD'} = `command /c cd`;
	356	chop $ENV{'PWD'};
	357	$ENV{'PWD'} =~ s:\\:/:g ;
	358	} else {
	359	$ENV{'PWD'} = Dos::GetCwd();
	360	}
55497cff	361	return $ENV{'PWD'};
	362	}
	363
7fbf1995	364	sub _qnx_cwd {
	365	$ENV{'PWD'} = `/usr/bin/fullpath -t`;
	366	chop $ENV{'PWD'};
	367	return $ENV{'PWD'};
	368	}
	369
	370	sub _qnx_abs_path {
fa921dc6	371	my $path = @_ ? shift : '.';
7fbf1995	372	my $realpath=`/usr/bin/fullpath -t $path`;
	373	chop $realpath;
	374	return $realpath;
	375	}
	376
ed79a026	377	sub _epoc_cwd {
	378	$ENV{'PWD'} = EPOC::getcwd();
	379	return $ENV{'PWD'};
	380	}
	381
ac1ad7f0	382	{
db376a24	383	no warnings; # assignments trigger 'subroutine redefined' warning
4633a7c4	384
ac1ad7f0	385	if ($^O eq 'VMS') {
96e4d5b1	386	*cwd = \&_vms_cwd;
	387	*getcwd = \&_vms_cwd;
	388	*fastcwd = \&_vms_cwd;
	389	*fastgetcwd = \&_vms_cwd;
	390	*abs_path = \&_vms_abs_path;
	391	*fast_abs_path = \&_vms_abs_path;
ac1ad7f0	392	}
	393	elsif ($^O eq 'NT' or $^O eq 'MSWin32') {
	394	# We assume that &_NT_cwd is defined as an XSUB or in the core.
96e4d5b1	395	*cwd = \&_NT_cwd;
	396	*getcwd = \&_NT_cwd;
	397	*fastcwd = \&_NT_cwd;
	398	*fastgetcwd = \&_NT_cwd;
	399	*abs_path = \&fast_abs_path;
ac1ad7f0	400	}
	401	elsif ($^O eq 'os2') {
	402	# sys_cwd may keep the builtin command
96e4d5b1	403	*cwd = defined &sys_cwd ? \&sys_cwd : \&_os2_cwd;
	404	*getcwd = \&cwd;
	405	*fastgetcwd = \&cwd;
	406	*fastcwd = \&cwd;
	407	*abs_path = \&fast_abs_path;
ac1ad7f0	408	}
39e571d4	409	elsif ($^O eq 'dos') {
	410	*cwd = \&_dos_cwd;
	411	*getcwd = \&_dos_cwd;
	412	*fastgetcwd = \&_dos_cwd;
	413	*fastcwd = \&_dos_cwd;
96e4d5b1	414	*abs_path = \&fast_abs_path;
ac1ad7f0	415	}
7438b6ad	416	elsif ($^O =~ m/^(?:qnx\|nto)$/ ) {
7fbf1995	417	*cwd = \&_qnx_cwd;
	418	*getcwd = \&_qnx_cwd;
	419	*fastgetcwd = \&_qnx_cwd;
	420	*fastcwd = \&_qnx_cwd;
	421	*abs_path = \&_qnx_abs_path;
	422	*fast_abs_path = \&_qnx_abs_path;
	423	}
4fabb596	424	elsif ($^O eq 'cygwin') {
1cab015a	425	*getcwd = \&cwd;
	426	*fastgetcwd = \&cwd;
	427	*fastcwd = \&cwd;
	428	*abs_path = \&fast_abs_path;
	429	}
ed79a026	430	elsif ($^O eq 'epoc') {
fa6a1c44	431	*cwd = \&_epoc_cwd;
fa6a1c44	432	*getcwd = \&_epoc_cwd;
ed79a026	433	*fastgetcwd = \&_epoc_cwd;
	434	*fastcwd = \&_epoc_cwd;
	435	*abs_path = \&fast_abs_path;
	436	}
4aecb5b5	437	elsif ($^O eq 'MacOS') {
	438	*getcwd = \&cwd;
	439	*fastgetcwd = \&cwd;
	440	*fastcwd = \&cwd;
	441	*abs_path = \&fast_abs_path;
	442	}
55497cff	443	}
4633a7c4	444
	445	# package main; eval join('',<DATA>) \|\| die $@; # quick test
	446
a0d0e21e	447	1;
a0d0e21e	448
4633a7c4	449	__END__
	450	BEGIN { import Cwd qw(:DEFAULT chdir); }
	451	print join("\n", cwd, getcwd, fastcwd, "");
	452	chdir('..');
	453	print join("\n", cwd, getcwd, fastcwd, "");
	454	print "$ENV{PWD}\n";