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package Cwd;
require 5.000;
require Exporter;
use Config;
=head1 NAME
getcwd - get pathname of current working directory
=head1 SYNOPSIS
require Cwd;
$dir = Cwd::getcwd();
use Cwd;
$dir = getcwd();
use Cwd 'chdir';
chdir "/tmp";
print $ENV{'PWD'};
=head1 DESCRIPTION
The getcwd() function re-implements the getcwd(3) (or getwd(3)) functions
in Perl. 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>.)
The fastgetcwd() function looks the same as getcwd(), but runs faster.
It's also more dangerous because you might conceivably chdir() out of a
directory that you can't chdir() back into.
=cut
@ISA = qw(Exporter);
@EXPORT = qw(getcwd fastcwd);
@EXPORT_OK = qw(chdir);
# VMS: $ENV{'DEFAULT'} points to default directory at all times
# 08-Dec-1994 Charles Bailey bailey@genetics.upenn.edu
# Note: Use of Cwd::getcwd() or Cwd::chdir() (but not Cwd::fastcwd())
# 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.
# By Brandon S. Allbery
#
# Usage: $cwd = getcwd();
sub getcwd
{
if($Config{'osname'} eq 'VMS') { return $ENV{'PWD'} = $ENV{'DEFAULT'} }
my($dotdots, $cwd, @pst, @cst, $dir, @tst);
unless (@cst = stat('.'))
{
warn "stat(.): $!";
return '';
}
$cwd = '';
$dotdots = '';
do
{
$dotdots .= '/' if $dotdots;
$dotdots .= '..';
@pst = @cst;
unless (opendir(PARENT, $dotdots))
{
warn "opendir($dotdots): $!";
return '';
}
unless (@cst = stat($dotdots))
{
warn "stat($dotdots): $!";
closedir(PARENT);
return '';
}
if ($pst[0] == $cst[0] && $pst[1] == $cst[1])
{
$dir = '';
}
else
{
do
{
unless (defined ($dir = readdir(PARENT)))
{
warn "readdir($dotdots): $!";
closedir(PARENT);
return '';
}
unless (@tst = lstat("$dotdots/$dir"))
{
warn "lstat($dotdots/$dir): $!";
closedir(PARENT);
return '';
}
}
while ($dir eq '.' || $dir eq '..' || $tst[0] != $pst[0] ||
$tst[1] != $pst[1]);
}
$cwd = "$dir/$cwd";
closedir(PARENT);
} while ($dir);
chop($cwd); # drop the trailing /
$cwd;
}
# By John Bazik
#
# Usage: $cwd = &fastcwd;
#
# This is a faster version of getcwd. It's also more dangerous because
# you might chdir out of a directory that you can't chdir back into.
sub fastcwd {
if($Config{'osname'} eq 'VMS') { return $ENV{'DEFAULT'} }
my($odev, $oino, $cdev, $cino, $tdev, $tino);
my(@path, $path);
local(*DIR);
($cdev, $cino) = stat('.');
for (;;) {
my $direntry;
($odev, $oino) = ($cdev, $cino);
chdir('..');
($cdev, $cino) = stat('.');
last if $odev == $cdev && $oino == $cino;
opendir(DIR, '.');
for (;;) {
$direntry = readdir(DIR);
next if $direntry eq '.';
next if $direntry eq '..';
last unless defined $direntry;
($tdev, $tino) = lstat($direntry);
last unless $tdev != $odev || $tino != $oino;
}
closedir(DIR);
unshift(@path, $direntry);
}
chdir($path = '/' . join('/', @path));
$path;
}
# keeps track of current working directory in PWD environment var
#
# $RCSfile: pwd.pl,v $$Revision: 4.1 $$Date: 92/08/07 18:24:11 $
#
# $Log: pwd.pl,v $
#
# Usage:
# use Cwd 'chdir';
# chdir $newdir;
$chdir_init = 0;
sub chdir_init{
if ($ENV{'PWD'}) {
my($dd,$di) = stat('.');
my($pd,$pi) = stat($ENV{'PWD'});
if (!defined $dd or !defined $pd or $di != $pi or $dd != $pd) {
chop($ENV{'PWD'} = `pwd`);
}
}
else {
chop($ENV{'PWD'} = `pwd`);
}
if ($ENV{'PWD'} =~ m|(/[^/]+(/[^/]+/[^/]+))(.*)|) {
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;
$newdir =~ s|/{2,}|/|g;
chdir_init() unless $chdir_init;
return 0 unless (CORE::chdir $newdir);
if ($Config{'osname'} eq 'VMS') { return $ENV{PWD} = $ENV{DEFAULT} }
if ($newdir =~ m#^/#) {
$ENV{'PWD'} = $newdir;
}else{
my(@curdir) = split(m#/#,$ENV{'PWD'});
@curdir = '' unless @curdir;
foreach $component (split(m#/#, $newdir)) {
next if $component eq '.';
pop(@curdir),next if $component eq '..';
push(@curdir,$component);
}
$ENV{'PWD'} = join('/',@curdir) || '/';
}
}
1;
|
