X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FFile%2FSpec%2FMac.pm;h=81016b309098e09c45350ac869146bd878c48734;hb=605986241de3d828e4de2beec37dc9ecc5aaa260;hp=2b0f5c896b4aa9be8701e0ba9a72c333acb757e9;hpb=b4408b2550ef78122084a50276f0f56ab8d9db27;p=p5sagit%2Fp5-mst-13.2.git

diff --git a/lib/File/Spec/Mac.pm b/lib/File/Spec/Mac.pm
index 2b0f5c8..81016b3 100644
--- a/lib/File/Spec/Mac.pm
+++ b/lib/File/Spec/Mac.pm
@@ -1,13 +1,24 @@
 package File::Spec::Mac;
 
 use strict;
-use vars qw(@ISA);
+use vars qw(@ISA $VERSION);
 require File::Spec::Unix;
+
+$VERSION = '1.4';
+
 @ISA = qw(File::Spec::Unix);
 
+my $macfiles;
+if ($^O eq 'MacOS') {
+	$macfiles = eval { require Mac::Files };
+}
+
+sub case_tolerant { 1 }
+
+
 =head1 NAME
 
-File::Spec::Mac - File::Spec for MacOS
+File::Spec::Mac - File::Spec for Mac OS (Classic)
 
 =head1 SYNOPSIS
 
@@ -23,7 +34,7 @@ Methods for manipulating file specifications.
 
 =item canonpath
 
-On MacOS, there's nothing to be done.  Returns what it's given.
+On Mac OS, there's nothing to be done. Returns what it's given.
 
 =cut
 
@@ -32,81 +43,273 @@ sub canonpath {
     return $path;
 }
 
-=item catdir
+=item catdir()
+
+Concatenate two or more directory names to form a path separated by colons
+(":") ending with a directory. Resulting paths are B<relative> by default,
+but can be forced to be absolute (but avoid this, see below). Automatically
+puts a trailing ":" on the end of the complete path, because that's what's
+done in MacPerl's environment and helps to distinguish a file path from a
+directory path.
+
+B<IMPORTANT NOTE:> Beginning with version 1.3 of this module, the resulting
+path is relative by default and I<not> absolute. This descision was made due
+to portability reasons. Since C<File::Spec-E<gt>catdir()> returns relative paths
+on all other operating systems, it will now also follow this convention on Mac
+OS. Note that this may break some existing scripts.
+
+The intended purpose of this routine is to concatenate I<directory names>.
+But because of the nature of Macintosh paths, some additional possibilities
+are allowed to make using this routine give reasonable results for some
+common situations. In other words, you are also allowed to concatenate
+I<paths> instead of directory names (strictly speaking, a string like ":a"
+is a path, but not a name, since it contains a punctuation character ":").
+
+So, beside calls like
+
+    catdir("a") = ":a:"
+    catdir("a","b") = ":a:b:"
+    catdir() = ""                    (special case)
+
+calls like the following
+
+    catdir(":a:") = ":a:"
+    catdir(":a","b") = ":a:b:"
+    catdir(":a:","b") = ":a:b:"
+    catdir(":a:",":b:") = ":a:b:"
+    catdir(":") = ":"
+
+are allowed.
+
+Here are the rules that are used in C<catdir()>; note that we try to be as
+compatible as possible to Unix:
+
+=over 2
+
+=item 1.
+
+The resulting path is relative by default, i.e. the resulting path will have a
+leading colon.
+
+=item 2.
+
+A trailing colon is added automatically to the resulting path, to denote a
+directory.
+
+=item 3.
+
+Generally, each argument has one leading ":" and one trailing ":"
+removed (if any). They are then joined together by a ":". Special
+treatment applies for arguments denoting updir paths like "::lib:",
+see (4), or arguments consisting solely of colons ("colon paths"),
+see (5).
+
+=item 4.
+
+When an updir path like ":::lib::" is passed as argument, the number
+of directories to climb up is handled correctly, not removing leading
+or trailing colons when necessary. E.g.
+
+    catdir(":::a","::b","c")    = ":::a::b:c:"
+    catdir(":::a::","::b","c")  = ":::a:::b:c:"
+
+=item 5.
+
+Adding a colon ":" or empty string "" to a path at I<any> position
+doesn't alter the path, i.e. these arguments are ignored. (When a ""
+is passed as the first argument, it has a special meaning, see
+(6)). This way, a colon ":" is handled like a "." (curdir) on Unix,
+while an empty string "" is generally ignored (see
+C<Unix-E<gt>canonpath()> ). Likewise, a "::" is handled like a ".."
+(updir), and a ":::" is handled like a "../.." etc.  E.g.
+
+    catdir("a",":",":","b")   = ":a:b:"
+    catdir("a",":","::",":b") = ":a::b:"
+
+=item 6.
 
-Concatenate two or more directory names to form a complete path ending with 
-a directory.  Put a trailing : on the end of the complete path if there 
-isn't one, because that's what's done in MacPerl's environment.
+If the first argument is an empty string "" or is a volume name, i.e. matches
+the pattern /^[^:]+:/, the resulting path is B<absolute>.
 
-The fundamental requirement of this routine is that
+=item 7.
 
-	  File::Spec->catdir(split(":",$path)) eq $path
+Passing an empty string "" as the first argument to C<catdir()> is
+like passingC<File::Spec-E<gt>rootdir()> as the first argument, i.e.
 
-But because of the nature of Macintosh paths, some additional 
-possibilities are allowed to make using this routine give reasonable results 
-for some common situations.  Here are the rules that are used.  Each 
-argument has its trailing ":" removed.  Each argument, except the first,
-has its leading ":" removed.  They are then joined together by a ":".
+    catdir("","a","b")          is the same as
 
-So
+    catdir(rootdir(),"a","b").
 
-	  File::Spec->catdir("a","b") = "a:b:"
-	  File::Spec->catdir("a:",":b") = "a:b:"
-	  File::Spec->catdir("a:","b") = "a:b:"
-	  File::Spec->catdir("a",":b") = "a:b"
-	  File::Spec->catdir("a","","b") = "a::b"
+This is true on Unix, where C<catdir("","a","b")> yields "/a/b" and
+C<rootdir()> is "/". Note that C<rootdir()> on Mac OS is the startup
+volume, which is the closest in concept to Unix' "/". This should help
+to run existing scripts originally written for Unix.
 
-etc.
+=item 8.
 
-To get a relative path (one beginning with :), begin the first argument with :
-or put a "" as the first argument.
+For absolute paths, some cleanup is done, to ensure that the volume
+name isn't immediately followed by updirs. This is invalid, because
+this would go beyond "root". Generally, these cases are handled like
+their Unix counterparts:
 
-If you don't want to worry about these rules, never allow a ":" on the ends 
-of any of the arguments except at the beginning of the first.
+ Unix:
+    Unix->catdir("","")                 =  "/"
+    Unix->catdir("",".")                =  "/"
+    Unix->catdir("","..")               =  "/"              # can't go beyond root
+    Unix->catdir("",".","..","..","a")  =  "/a"
+ Mac:
+    Mac->catdir("","")                  =  rootdir()         # (e.g. "HD:")
+    Mac->catdir("",":")                 =  rootdir()
+    Mac->catdir("","::")                =  rootdir()         # can't go beyond root
+    Mac->catdir("",":","::","::","a")   =  rootdir() . "a:"  # (e.g. "HD:a:")
 
-Under MacPerl, there is an additional ambiguity.  Does the user intend that
+However, this approach is limited to the first arguments following
+"root" (again, see C<Unix-E<gt>canonpath()> ). If there are more
+arguments that move up the directory tree, an invalid path going
+beyond root can be created.
 
-	  File::Spec->catfile("LWP","Protocol","http.pm")
+=back
+
+As you've seen, you can force C<catdir()> to create an absolute path
+by passing either an empty string or a path that begins with a volume
+name as the first argument. However, you are strongly encouraged not
+to do so, since this is done only for backward compatibility. Newer
+versions of File::Spec come with a method called C<catpath()> (see
+below), that is designed to offer a portable solution for the creation
+of absolute paths.  It takes volume, directory and file portions and
+returns an entire path. While C<catdir()> is still suitable for the
+concatenation of I<directory names>, you are encouraged to use
+C<catpath()> to concatenate I<volume names> and I<directory
+paths>. E.g.
+
+    $dir      = File::Spec->catdir("tmp","sources");
+    $abs_path = File::Spec->catpath("MacintoshHD:", $dir,"");
+
+yields
 
-be relative or absolute?  There's no way of telling except by checking for the
-existence of LWP: or :LWP, and even there he may mean a dismounted volume or
-a relative path in a different directory (like in @INC).   So those checks
-aren't done here. This routine will treat this as absolute.
+    "MacintoshHD:tmp:sources:" .
 
 =cut
 
 sub catdir {
-    shift;
-    my @args = @_;
-    my $result = shift @args;
-    $result =~ s/:\Z(?!\n)//;
-    foreach (@args) {
-	s/:\Z(?!\n)//;
-	s/^://s;
-	$result .= ":$_";
-    }
-    return "$result:";
+	my $self = shift;
+	return '' unless @_;
+	my @args = @_;
+	my $first_arg;
+	my $relative;
+
+	# take care of the first argument
+
+	if ($args[0] eq '')  { # absolute path, rootdir
+		shift @args;
+		$relative = 0;
+		$first_arg = $self->rootdir;
+
+	} elsif ($args[0] =~ /^[^:]+:/) { # absolute path, volume name
+		$relative = 0;
+		$first_arg = shift @args;
+		# add a trailing ':' if need be (may be it's a path like HD:dir)
+		$first_arg = "$first_arg:" unless ($first_arg =~ /:\Z(?!\n)/);
+
+	} else { # relative path
+		$relative = 1;
+		if ( $args[0] =~ /^::+\Z(?!\n)/ ) {
+			# updir colon path ('::', ':::' etc.), don't shift
+			$first_arg = ':';
+		} elsif ($args[0] eq ':') {
+			$first_arg = shift @args;
+		} else {
+			# add a trailing ':' if need be
+			$first_arg = shift @args;
+			$first_arg = "$first_arg:" unless ($first_arg =~ /:\Z(?!\n)/);
+		}
+	}
+
+	# For all other arguments,
+	# (a) ignore arguments that equal ':' or '',
+	# (b) handle updir paths specially:
+	#     '::' 			-> concatenate '::'
+	#     '::' . '::' 	-> concatenate ':::' etc.
+	# (c) add a trailing ':' if need be
+
+	my $result = $first_arg;
+	while (@args) {
+		my $arg = shift @args;
+		unless (($arg eq '') || ($arg eq ':')) {
+			if ($arg =~ /^::+\Z(?!\n)/ ) { # updir colon path like ':::'
+				my $updir_count = length($arg) - 1;
+				while ((@args) && ($args[0] =~ /^::+\Z(?!\n)/) ) { # while updir colon path
+					$arg = shift @args;
+					$updir_count += (length($arg) - 1);
+				}
+				$arg = (':' x $updir_count);
+			} else {
+				$arg =~ s/^://s; # remove a leading ':' if any
+				$arg = "$arg:" unless ($arg =~ /:\Z(?!\n)/); # ensure trailing ':'
+			}
+			$result .= $arg;
+		}#unless
+	}
+
+	if ( ($relative) && ($result !~ /^:/) ) {
+		# add a leading colon if need be
+		$result = ":$result";
+	}
+
+	unless ($relative) {
+		# remove updirs immediately following the volume name
+		$result =~ s/([^:]+:)(:*)(.*)\Z(?!\n)/$1$3/;
+	}
+
+	return $result;
 }
 
 =item catfile
 
 Concatenate one or more directory names and a filename to form a
-complete path ending with a filename.  Since this uses catdir, the
-same caveats apply.  Note that the leading : is removed from the filename,
-so that 
+complete path ending with a filename. Resulting paths are B<relative>
+by default, but can be forced to be absolute (but avoid this).
+
+B<IMPORTANT NOTE:> Beginning with version 1.3 of this module, the
+resulting path is relative by default and I<not> absolute. This
+descision was made due to portability reasons. Since
+C<File::Spec-E<gt>catfile()> returns relative paths on all other
+operating systems, it will now also follow this convention on Mac OS.
+Note that this may break some existing scripts.
+
+The last argument is always considered to be the file portion. Since
+C<catfile()> uses C<catdir()> (see above) for the concatenation of the
+directory portions (if any), the following with regard to relative and
+absolute paths is true:
+
+    catfile("")     = ""
+    catfile("file") = "file"
 
-	  File::Spec->catfile($ENV{HOME},"file");
+but
 
-and
+    catfile("","")        = rootdir()         # (e.g. "HD:")
+    catfile("","file")    = rootdir() . file  # (e.g. "HD:file")
+    catfile("HD:","file") = "HD:file"
 
-	  File::Spec->catfile($ENV{HOME},":file");
+This means that C<catdir()> is called only when there are two or more
+arguments, as one might expect.
 
-give the same answer, as one might expect.
+Note that the leading ":" is removed from the filename, so that
+
+    catfile("a","b","file")  = ":a:b:file"    and
+
+    catfile("a","b",":file") = ":a:b:file"
+
+give the same answer.
+
+To concatenate I<volume names>, I<directory paths> and I<filenames>,
+you are encouraged to use C<catpath()> (see below).
 
 =cut
 
 sub catfile {
     my $self = shift;
+    return '' unless @_;
     my $file = pop @_;
     return $file unless @_;
     my $dir = $self->catdir(@_);
@@ -116,7 +319,7 @@ sub catfile {
 
 =item curdir
 
-Returns a string representing the current directory.
+Returns a string representing the current directory. On Mac OS, this is ":".
 
 =cut
 
@@ -126,7 +329,7 @@ sub curdir {
 
 =item devnull
 
-Returns a string representing the null device.
+Returns a string representing the null device. On Mac OS, this is "Dev:Null".
 
 =cut
 
@@ -138,42 +341,44 @@ sub devnull {
 
 Returns a string representing the root directory.  Under MacPerl,
 returns the name of the startup volume, since that's the closest in
-concept, although other volumes aren't rooted there.
+concept, although other volumes aren't rooted there. The name has a
+trailing ":", because that's the correct specification for a volume
+name on Mac OS.
+
+If Mac::Files could not be loaded, the empty string is returned.
 
 =cut
 
 sub rootdir {
 #
-#  There's no real root directory on MacOS.  The name of the startup
+#  There's no real root directory on Mac OS. The name of the startup
 #  volume is returned, since that's the closest in concept.
 #
-    require Mac::Files;
-    my $system =  Mac::Files::FindFolder(&Mac::Files::kOnSystemDisk,
-					 &Mac::Files::kSystemFolderType);
+    return '' unless $macfiles;
+    my $system = Mac::Files::FindFolder(&Mac::Files::kOnSystemDisk,
+	&Mac::Files::kSystemFolderType);
     $system =~ s/:.*\Z(?!\n)/:/s;
     return $system;
 }
 
 =item tmpdir
 
-Returns a string representation of the first existing directory
-from the following list or '' if none exist:
-
-    $ENV{TMPDIR}
+Returns the contents of $ENV{TMPDIR}, if that directory exits or the
+current working directory otherwise. Under MacPerl, $ENV{TMPDIR} will
+contain a path like "MacintoshHD:Temporary Items:", which is a hidden
+directory on your startup volume.
 
 =cut
 
 my $tmpdir;
 sub tmpdir {
     return $tmpdir if defined $tmpdir;
-    $tmpdir = $ENV{TMPDIR} if -d $ENV{TMPDIR};
-    $tmpdir = '' unless defined $tmpdir;
-    return $tmpdir;
+    $tmpdir = $_[0]->_tmpdir( $ENV{TMPDIR} );
 }
 
 =item updir
 
-Returns a string representing the parent directory.
+Returns a string representing the parent directory. On Mac OS, this is "::".
 
 =cut
 
@@ -183,28 +388,41 @@ sub updir {
 
 =item file_name_is_absolute
 
-Takes as argument a path and returns true, if it is an absolute path.  In 
-the case where a name can be either relative or absolute (for example, a 
-folder named "HD" in the current working directory on a drive named "HD"), 
-relative wins.  Use ":" in the appropriate place in the path if you want to
-distinguish unambiguously.
+Takes as argument a path and returns true, if it is an absolute path.
+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);
+	return (! ($file =~ m/^:/s) );
+    } elsif ( $file eq '' ) {
+        return 1 ;
     } else {
-	return (! -e ":$file");
+	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 MacOS. But if you're using the MacPerl tool under 
-MPW, it gives back $ENV{Commands} suitably split, as is done in 
+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
@@ -220,92 +438,221 @@ sub path {
 
 =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) = ('','','');
+    my ($volume,$directory,$file);
 
     if ( $nofile ) {
-        ( $volume, $directory ) = $path =~ m@((?:[^:]+(?::|\Z(?!\n)))?)(.*)@s;
+        ( $volume, $directory ) = $path =~ m|^((?:[^:]+:)?)(.*)|s;
     }
     else {
-        $path =~ 
-            m@^( (?: [^:]+: )? ) 
-                ( (?: .*: )? )
-                ( .* )
-             @xs;
+        $path =~
+            m|^( (?: [^:]+: )? )
+               ( (?: .*: )? )
+               ( .* )
+             |xs;
         $volume    = $1;
         $directory = $2;
         $file      = $3;
     }
 
-    # Make sure non-empty volumes and directories end in ':'
-    $volume    .= ':' if $volume    =~ m@[^:]\Z(?!\n)@ ;
-    $directory .= ':' if $directory =~ m@[^:]\Z(?!\n)@ ;
+    $volume = '' unless defined($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 ($self,$directories) = @_ ;
-    #
-    # split() likes to forget about trailing null fields, so here we
-    # check to be sure that there will not be any before handling the
-    # simple case.
-    #
-    if ( $directories !~ m@:\Z(?!\n)@ ) {
-        return split( m@:@, $directories );
-    }
-    else {
-        #
-        # since there was a trailing separator, add a file name to the end, 
-        # then do the split, then replace it with ''.
-        #
-        my( @directories )= split( m@:@, "${directories}dummy" ) ;
-        $directories[ $#directories ]= '' ;
-        return @directories ;
-    }
+	my ($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 $self = shift ;
+    my ($self,$volume,$directory,$file) = @_;
 
-    my $result = shift ;
-    $result =~ s@^([^/])@/$1@s ;
+    if ( (! $volume) && (! $directory) ) {
+	$file =~ s/^:// if $file;
+	return $file ;
+    }
 
-    my $segment ;
-    for $segment ( @_ ) {
-        if ( $result =~ m@[^/]\Z(?!\n)@ && $segment =~ m@^[^/]@s ) {
-            $result .= "/$segment" ;
-        }
-        elsif ( $result =~ m@/\Z(?!\n)@ && $segment =~ m@^/@s ) {
-            $result  =~ s@/+\Z(?!\n)@/@;
-            $segment =~ s@^/+@@s;
-            $result  .= "$segment" ;
-        }
-        else {
-            $result  .= $segment ;
-        }
+    # 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 ':'
     }
 
-    return $result ;
+    if ($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) = @_;
 
@@ -316,81 +663,117 @@ sub abs2rel {
 
     # Figure out the effective $base and clean it up.
     if ( !defined( $base ) || $base eq '' ) {
-        $base = cwd() ;
+	$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 );
     }
 
-    # Now, remove all leading components that are the same
-    my @pathchunks = $self->splitdir( $path );
-    my @basechunks = $self->splitdir( $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 );
 
-    while (@pathchunks && @basechunks && $pathchunks[0] eq $basechunks[0]) {
+    # 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 ;
     }
 
-    $path = join( ':', @pathchunks );
+    # @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 = ':' x @basechunks ;
+    $base_dirs = (':' x @basechunks) . ':' ;
 
-    return "$base:$path" ;
+    return $self->catpath( '', $self->catdir( $base_dirs, $path_dirs ), $path_file ) ;
 }
 
 =item rel2abs
 
-Converts a relative path to an absolute path. 
+Converts a relative path to an absolute path:
 
-    $abs_path = File::Spec->rel2abs( $destination ) ;
-    $abs_path = File::Spec->rel2abs( $destination, $base ) ;
+    $abs_path = File::Spec->rel2abs( $path ) ;
+    $abs_path = File::Spec->rel2abs( $path, $base ) ;
 
-If $base is not present or '', then L<cwd()> is used. If $base is relative, 
-then it is converted to absolute form using L</rel2abs()>. This means that it
-is taken to be relative to L<cwd()>.
+Note that both paths are assumed to have a notation that distinguishes a
+directory path (with trailing ':') from a file path (without trailing ':').
 
-On systems with the concept of a volume, this assumes that both paths 
-are on the $base volume, and ignores the $destination volume. 
+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.
 
-On systems that have a grammar that indicates filenames, this ignores the 
-$base filename as well. Otherwise all path components are assumed to be
-directories.
+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 absolute, it is cleaned up and returned using L</canonpath()>.
+If $path is already absolute, it is returned and $base is ignored.
 
 Based on code written by Shigio Yamaguchi.
 
-No checks against the filesystem are made. 
-
 =cut
 
-sub rel2abs($;$;) {
-    my ($self,$path,$base ) = @_;
+sub rel2abs {
+    my ($self,$path,$base) = @_;
 
-    if ( ! $self->file_name_is_absolute( $path ) ) {
+    if ( ! $self->file_name_is_absolute($path) ) {
+        # Figure out the effective $base and clean it up.
         if ( !defined( $base ) || $base eq '' ) {
-            $base = cwd() ;
-        }
-        elsif ( ! $self->file_name_is_absolute( $base ) ) {
-            $base = $self->rel2abs( $base ) ;
+	    $base = $self->_cwd();
         }
-        else {
-            $base = $self->canonpath( $base ) ;
+        elsif ( ! $self->file_name_is_absolute($base) ) {
+            $base = $self->rel2abs($base) ;
         }
 
-        $path = $self->canonpath("$base$path") ;
-    }
+	# 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;
 
-    return $path ;
+        $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
+<schinder@pobox.com> and Thomas Wegner <wegner_thomas@yahoo.com>.
+
+=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
 
-L<File::Spec>
+See L<File::Spec> and L<File::Spec::Unix>.  This package overrides the
+implementation of these methods, not the semantics.
 
 =cut