PC World 2003 March/PCWorld_2003-03_cd.bin/Software/Topware/activeperl/ActivePerl/Perl/lib/File/Path.pm

Perl POD Document | 2002-06-19 | 7.4 KB | 268 lines

package File::Path;

=head1 NAME

File::Path - create or remove directory trees

=head1 SYNOPSIS

    use File::Path;

    mkpath(['/foo/bar/baz', 'blurfl/quux'], 1, 0711);
    rmtree(['foo/bar/baz', 'blurfl/quux'], 1, 1);

=head1 DESCRIPTION

The C<mkpath> function provides a convenient way to create directories, even
if your C<mkdir> kernel call won't create more than one level of directory at
a time.  C<mkpath> takes three arguments:

=over 4

=item *

the name of the path to create, or a reference
to a list of paths to create,

=item *

a boolean value, which if TRUE will cause C<mkpath>
to print the name of each directory as it is created
(defaults to FALSE), and

=item *

the numeric mode to use when creating the directories
(defaults to 0777)

=back

It returns a list of all directories (including intermediates, determined
using the Unix '/' separator) created.

If a system error prevents a directory from being created, then the
C<mkpath> function throws a fatal error with C<Carp::croak>. This error
can be trapped with an C<eval> block:

  eval { mkpath($dir) };
  if ($@) {
    print "Couldn't create $dir: $@";
  }

Similarly, the C<rmtree> function provides a convenient way to delete a
subtree from the directory structure, much like the Unix command C<rm -r>.
C<rmtree> takes three arguments:

=over 4

=item *

the root of the subtree to delete, or a reference to
a list of roots.  All of the files and directories
below each root, as well as the roots themselves,
will be deleted.

=item *

a boolean value, which if TRUE will cause C<rmtree> to
print a message each time it examines a file, giving the
name of the file, and indicating whether it's using C<rmdir>
or C<unlink> to remove it, or that it's skipping it.
(defaults to FALSE)

=item *

a boolean value, which if TRUE will cause C<rmtree> to
skip any files to which you do not have delete access
(if running under VMS) or write access (if running
under another OS).  This will change in the future when
a criterion for 'delete permission' under OSs other
than VMS is settled.  (defaults to FALSE)

=back

It returns the number of files successfully deleted.  Symlinks are
simply deleted and not followed.

B<NOTE:> If the third parameter is not TRUE, C<rmtree> is B<unsecure>
in the face of failure or interruption.  Files and directories which
were not deleted may be left with permissions reset to allow world
read and write access.  Note also that the occurrence of errors in
rmtree can be determined I<only> by trapping diagnostic messages
using C<$SIG{__WARN__}>; it is not apparent from the return value.
Therefore, you must be extremely careful about using C<rmtree($foo,$bar,0>
in situations where security is an issue.

=head1 AUTHORS

Tim Bunce <F<[e-mail]>> and
Charles Bailey <F<[e-mail]>>

=cut

use 5.006;
use Carp;
use File::Basename ();
use Exporter ();
use strict;
use warnings;

our $VERSION = "1.05";
our @ISA = qw( Exporter );
our @EXPORT = qw( mkpath rmtree );

my $Is_VMS = $^O eq 'VMS';
my $Is_MacOS = $^O eq 'MacOS';

# These OSes complain if you want to remove a file that you have no
# write permission to:
my $force_writeable = ($^O eq 'os2' || $^O eq 'dos' || $^O eq 'MSWin32' ||
               $^O eq 'amigaos' || $^O eq 'MacOS' || $^O eq 'epoc');

sub mkpath {
    my($paths, $verbose, $mode) = @_;
    # $paths   -- either a path string or ref to list of paths
    # $verbose -- optional print "mkdir $path" for each directory created
    # $mode    -- optional permissions, defaults to 0777
    local($")=$Is_MacOS ? ":" : "/";
    $mode = 0777 unless defined($mode);
    $paths = [$paths] unless ref $paths;
    my(@created,$path);
    foreach $path (@$paths) {
    $path .= '/' if $^O eq 'os2' and $path =~ /^\w:\z/s; # feature of CRT
    # Logic wants Unix paths, so go with the flow.
    if ($Is_VMS) {
        next if $path eq '/';
        $path = VMS::Filespec::unixify($path);
        if ($path =~ m:^(/[^/]+)/?\z:) {
            $path = $1.'/000000';
        }
    }
    next if -d $path;
    my $parent = File::Basename::dirname($path);
    unless (-d $parent or $path eq $parent) {
        push(@created,mkpath($parent, $verbose, $mode));
     }
    print "mkdir $path\n" if $verbose;
    unless (mkdir($path,$mode)) {
        my $e = $!;
        # allow for another process to have created it meanwhile
        croak "mkdir $path: $e" unless -d $path;
    }
    push(@created, $path);
    }
    @created;
}

sub rmtree {
    my($roots, $verbose, $safe) = @_;
    my(@files);
    my($count) = 0;
    $verbose ||= 0;
    $safe ||= 0;

    if ( defined($roots) && length($roots) ) {
      $roots = [$roots] unless ref $roots;
    }
    else {
      carp "No root path(s) specified\n";
      return 0;
    }

    my($root);
    foreach $root (@{$roots}) {
        if ($Is_MacOS) {
        $root = ":$root" if $root !~ /:/;
        $root =~ s#([^:])\z#$1:#;
    } else {
        $root =~ s#/\z##;
    }
    (undef, undef, my $rp) = lstat $root or next;
    $rp &= 07777;    # don't forget setuid, setgid, sticky bits
    if ( -d _ ) {
        # notabene: 0777 is for making readable in the first place,
        # it's also intended to change it to writable in case we have
        # to recurse in which case we are better than rm -rf for
        # subtrees with strange permissions
        chmod(0777, ($Is_VMS ? VMS::Filespec::fileify($root) : $root))
          or carp "Can't make directory $root read+writeable: $!"
        unless $safe;

        if (opendir my $d, $root) {
        no strict 'refs';
        if (!defined ${"\cTAINT"} or ${"\cTAINT"}) {
            # Blindly untaint dir names
            @files = map { /^(.*)$/s ; $1 } readdir $d;
        } else {
            @files = readdir $d;
        }
        closedir $d;
        }
        else {
            carp "Can't read $root: $!";
        @files = ();
        }

        # Deleting large numbers of files from VMS Files-11 filesystems
        # is faster if done in reverse ASCIIbetical order
        @files = reverse @files if $Is_VMS;
        ($root = VMS::Filespec::unixify($root)) =~ s#\.dir\z## if $Is_VMS;
        if ($Is_MacOS) {
        @files = map("$root$_", @files);
        } else {
        @files = map("$root/$_", grep $_!~/^\.{1,2}\z/s,@files);
        }
        $count += rmtree(\@files,$verbose,$safe);
        if ($safe &&
        ($Is_VMS ? !&VMS::Filespec::candelete($root) : !-w $root)) {
        print "skipped $root\n" if $verbose;
        next;
        }
        chmod 0777, $root
          or carp "Can't make directory $root writeable: $!"
        if $force_writeable;
        print "rmdir $root\n" if $verbose;
        if (rmdir $root) {
        ++$count;
        }
        else {
        carp "Can't remove directory $root: $!";
        chmod($rp, ($Is_VMS ? VMS::Filespec::fileify($root) : $root))
            or carp("and can't restore permissions to "
                    . sprintf("0%o",$rp) . "\n");
        }
    }
    else {
        if ($safe &&
        ($Is_VMS ? !&VMS::Filespec::candelete($root)
                 : !(-l $root || -w $root)))
        {
        print "skipped $root\n" if $verbose;
        next;
        }
        chmod 0666, $root
          or carp "Can't make file $root writeable: $!"
        if $force_writeable;
        print "unlink $root\n" if $verbose;
        # delete all versions under VMS
        for (;;) {
        unless (unlink $root) {
            carp "Can't unlink file $root: $!";
            if ($force_writeable) {
            chmod $rp, $root
                or carp("and can't restore permissions to "
                        . sprintf("0%o",$rp) . "\n");
            }
            last;
        }
        ++$count;
        last unless $Is_VMS && lstat $root;
        }
    }
    }

    $count;
}

1;