mac.pm

source of perl for linux application,

If the path has a leading ":", it's a relative path. Otherwise, it's an
absolute path, unless the path doesn't contain any colons, i.e. it's a name
like "a". In this particular case, the path is considered to be relative
(i.e. it is considered to be a filename). Use ":" in the appropriate place
in the path if you want to distinguish unambiguously. As a special case,
the filename '' is always considered to be absolute. Note that with version
1.2 of File::Spec::Mac, this does no longer consult the local filesystem.

E.g.

    File::Spec->file_name_is_absolute("a");             # false (relative)
    File::Spec->file_name_is_absolute(":a:b:");         # false (relative)
    File::Spec->file_name_is_absolute("MacintoshHD:");  # true (absolute)
    File::Spec->file_name_is_absolute("");              # true (absolute)


=cut

sub file_name_is_absolute {
    my ($self,$file) = @_;
    if ($file =~ /:/) {
	return (! ($file =~ m/^:/s) );
    } elsif ( $file eq '' ) {
        return 1 ;
    } else {
	return 0; # i.e. a file like "a"
    }
}

=item path

Returns the null list for the MacPerl application, since the concept is
usually meaningless under Mac OS. But if you're using the MacPerl tool under
MPW, it gives back $ENV{Commands} suitably split, as is done in
:lib:ExtUtils:MM_Mac.pm.

=cut

sub path {
#
#  The concept is meaningless under the MacPerl application.
#  Under MPW, it has a meaning.
#
    return unless exists $ENV{Commands};
    return split(/,/, $ENV{Commands});
}

=item splitpath

    ($volume,$directories,$file) = File::Spec->splitpath( $path );
    ($volume,$directories,$file) = File::Spec->splitpath( $path, $no_file );

Splits a path into volume, directory, and filename portions.

On Mac OS, assumes that the last part of the path is a filename unless
$no_file is true or a trailing separator ":" is present.

The volume portion is always returned with a trailing ":". The directory portion
is always returned with a leading (to denote a relative path) and a trailing ":"
(to denote a directory). The file portion is always returned I<without> a leading ":".
Empty portions are returned as empty string ''.

The results can be passed to C<catpath()> to get back a path equivalent to
(usually identical to) the original path.


=cut

sub splitpath {
    my ($self,$path, $nofile) = @_;
    my ($volume,$directory,$file);

    if ( $nofile ) {
        ( $volume, $directory ) = $path =~ m|^((?:[^:]+:)?)(.*)|s;
    }
    else {
        $path =~
            m|^( (?: [^:]+: )? )
               ( (?: .*: )? )
               ( .* )
             |xs;
        $volume    = $1;
        $directory = $2;
        $file      = $3;
    }

    $volume = '' unless defined($volume);
	$directory = ":$directory" if ( $volume && $directory ); # take care of "HD::dir"
    if ($directory) {
        # Make sure non-empty directories begin and end in ':'
        $directory .= ':' unless (substr($directory,-1) eq ':');
        $directory = ":$directory" unless (substr($directory,0,1) eq ':');
    } else {
	$directory = '';
    }
    $file = '' unless defined($file);

    return ($volume,$directory,$file);
}


=item splitdir

The opposite of C<catdir()>.

    @dirs = File::Spec->splitdir( $directories );

$directories should be only the directory portion of the path on systems
that have the concept of a volume or that have path syntax that differentiates
files from directories. Consider using C<splitpath()> otherwise.

Unlike just splitting the directories on the separator, empty directory names
(C<"">) can be returned. Since C<catdir()> on Mac OS always appends a trailing
colon to distinguish a directory path from a file path, a single trailing colon
will be ignored, i.e. there's no empty directory name after it.

Hence, on Mac OS, both

    File::Spec->splitdir( ":a:b::c:" );    and
    File::Spec->splitdir( ":a:b::c" );

yield:

    ( "a", "b", "::", "c")

while

    File::Spec->splitdir( ":a:b::c::" );

yields:

    ( "a", "b", "::", "c", "::")


=cut

sub splitdir {
	my ($self, $path) = @_;
	my @result = ();
	my ($head, $sep, $tail, $volume, $directories);

	return ('') if ( (!defined($path)) || ($path eq '') );
	return (':') if ($path eq ':');

	( $volume, $sep, $directories ) = $path =~ m|^((?:[^:]+:)?)(:*)(.*)|s;

	# deprecated, but handle it correctly
	if ($volume) {
		push (@result, $volume);
		$sep .= ':';
	}

	while ($sep || $directories) {
		if (length($sep) > 1) {
			my $updir_count = length($sep) - 1;
			for (my $i=0; $i<$updir_count; $i++) {
				# push '::' updir_count times;
				# simulate Unix '..' updirs
				push (@result, '::');
			}
		}
		$sep = '';
		if ($directories) {
			( $head, $sep, $tail ) = $directories =~ m|^((?:[^:]+)?)(:*)(.*)|s;
			push (@result, $head);
			$directories = $tail;
		}
	}
	return @result;
}


=item catpath

    $path = File::Spec->catpath($volume,$directory,$file);

Takes volume, directory and file portions and returns an entire path. On Mac OS,
$volume, $directory and $file are concatenated.  A ':' is inserted if need be. You
may pass an empty string for each portion. If all portions are empty, the empty
string is returned. If $volume is empty, the result will be a relative path,
beginning with a ':'. If $volume and $directory are empty, a leading ":" (if any)
is removed form $file and the remainder is returned. If $file is empty, the
resulting path will have a trailing ':'.


=cut

sub catpath {
    my ($self,$volume,$directory,$file) = @_;

    if ( (! $volume) && (! $directory) ) {
	$file =~ s/^:// if $file;
	return $file ;
    }

    # We look for a volume in $volume, then in $directory, but not both

    my ($dir_volume, $dir_dirs) = $self->splitpath($directory, 1);

    $volume = $dir_volume unless length $volume;
    my $path = $volume; # may be ''
    $path .= ':' unless (substr($path, -1) eq ':'); # ensure trailing ':'

    if ($directory) {
	$directory = $dir_dirs if $volume;
	$directory =~ s/^://; # remove leading ':' if any
	$path .= $directory;
	$path .= ':' unless (substr($path, -1) eq ':'); # ensure trailing ':'
    }

    if ($file) {
	$file =~ s/^://; # remove leading ':' if any
	$path .= $file;
    }

    return $path;
}

=item abs2rel

Takes a destination path and an optional base path and returns a relative path
from the base path to the destination path:

    $rel_path = File::Spec->abs2rel( $path ) ;
    $rel_path = File::Spec->abs2rel( $path, $base ) ;

Note that both paths are assumed to have a notation that distinguishes a
directory path (with trailing ':') from a file path (without trailing ':').

If $base is not present or '', then the current working directory is used.
If $base is relative, then it is converted to absolute form using C<rel2abs()>.
This means that it is taken to be relative to the current working directory.

If $path and $base appear to be on two different volumes, we will not
attempt to resolve the two paths, and we will instead simply return
$path.  Note that previous versions of this module ignored the volume
of $base, which resulted in garbage results part of the time.

If $base doesn't have a trailing colon, the last element of $base is
assumed to be a filename.  This filename is ignored.  Otherwise all path
components are assumed to be directories.

If $path is relative, it is converted to absolute form using C<rel2abs()>.
This means that it is taken to be relative to the current working directory.

Based on code written by Shigio Yamaguchi.


=cut

# maybe this should be done in canonpath() ?
sub _resolve_updirs {
	my $path = shift @_;
	my $proceed;

	# resolve any updirs, e.g. "HD:tmp::file" -> "HD:file"
	do {
		$proceed = ($path =~ s/^(.*):[^:]+::(.*?)\z/$1:$2/);
	} while ($proceed);

	return $path;
}


sub abs2rel {
    my($self,$path,$base) = @_;

    # Clean up $path
    if ( ! $self->file_name_is_absolute( $path ) ) {
        $path = $self->rel2abs( $path ) ;
    }

    # Figure out the effective $base and clean it up.
    if ( !defined( $base ) || $base eq '' ) {
	$base = $self->_cwd();
    }
    elsif ( ! $self->file_name_is_absolute( $base ) ) {
        $base = $self->rel2abs( $base ) ;
	$base = _resolve_updirs( $base ); # resolve updirs in $base
    }
    else {
	$base = _resolve_updirs( $base );
    }

    # Split up paths - ignore $base's file
    my ( $path_vol, $path_dirs, $path_file ) =  $self->splitpath( $path );
    my ( $base_vol, $base_dirs )             =  $self->splitpath( $base );

    return $path unless lc( $path_vol ) eq lc( $base_vol );

    # Now, remove all leading components that are the same
    my @pathchunks = $self->splitdir( $path_dirs );
    my @basechunks = $self->splitdir( $base_dirs );
	
    while ( @pathchunks &&
	    @basechunks &&
	    lc( $pathchunks[0] ) eq lc( $basechunks[0] ) ) {
        shift @pathchunks ;
        shift @basechunks ;
    }

    # @pathchunks now has the directories to descend in to.
    # ensure relative path, even if @pathchunks is empty
    $path_dirs = $self->catdir( ':', @pathchunks );

    # @basechunks now contains the number of directories to climb out of.
    $base_dirs = (':' x @basechunks) . ':' ;

    return $self->catpath( '', $self->catdir( $base_dirs, $path_dirs ), $path_file ) ;
}

=item rel2abs

Converts a relative path to an absolute path:

    $abs_path = File::Spec->rel2abs( $path ) ;
    $abs_path = File::Spec->rel2abs( $path, $base ) ;

Note that both paths are assumed to have a notation that distinguishes a
directory path (with trailing ':') from a file path (without trailing ':').

If $base is not present or '', then $base is set to the current working
directory. If $base is relative, then it is converted to absolute form
using C<rel2abs()>. This means that it is taken to be relative to the
current working directory.

If $base doesn't have a trailing colon, the last element of $base is
assumed to be a filename.  This filename is ignored.  Otherwise all path
components are assumed to be directories.

If $path is already absolute, it is returned and $base is ignored.

Based on code written by Shigio Yamaguchi.

=cut

sub rel2abs {
    my ($self,$path,$base) = @_;

    if ( ! $self->file_name_is_absolute($path) ) {
        # Figure out the effective $base and clean it up.
        if ( !defined( $base ) || $base eq '' ) {
	    $base = $self->_cwd();
        }
        elsif ( ! $self->file_name_is_absolute($base) ) {
            $base = $self->rel2abs($base) ;
        }

	# Split up paths

	# igonore $path's volume
        my ( $path_dirs, $path_file ) = ($self->splitpath($path))[1,2] ;

        # ignore $base's file part
	my ( $base_vol, $base_dirs ) = $self->splitpath($base) ;

	# Glom them together
	$path_dirs = ':' if ($path_dirs eq '');
	$base_dirs =~ s/:$//; # remove trailing ':', if any
	$base_dirs = $base_dirs . $path_dirs;

        $path = $self->catpath( $base_vol, $base_dirs, $path_file );
    }
    return $path;
}


=back

=head1 AUTHORS

See the authors list in I<File::Spec>. Mac OS support by Paul Schinder
<[e-mail]> and Thomas Wegner <[e-mail]>.

=head1 COPYRIGHT

Copyright (c) 2004 by the Perl 5 Porters.  All rights reserved.

This program is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.

=head1 SEE ALSO

See L<File::Spec> and L<File::Spec::Unix>.  This package overrides the
implementation of these methods, not the semantics.

=cut

1;