NAME¶
File::Spec::Mac - File::Spec for Mac OS (Classic)
SYNOPSIS¶
require File::Spec::Mac; # Done internally by File::Spec if needed
DESCRIPTION¶
Methods for manipulating file specifications.
METHODS¶
- canonpath
- On Mac OS, there's nothing to be done. Returns what it's given.
- catdir()
- Concatenate two or more directory names to form a path separated by colons
(":") ending with a directory. Resulting paths are
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.
IMPORTANT NOTE: Beginning with version 1.3 of this module, the
resulting path is relative by default and not absolute. This
decision was made due to portability reasons. Since
"File::Spec->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 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 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 "catdir()"; note that we try
to be as compatible as possible to Unix:
- 1.
- The resulting path is relative by default, i.e. the resulting path will
have a leading colon.
- 2.
- A trailing colon is added automatically to the resulting path, to denote a
directory.
- 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).
- 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:"
- 5.
- Adding a colon ":" or empty string "" to a path at
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 "Unix->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:"
- 6.
- If the first argument is an empty string "" or is a volume name,
i.e. matches the pattern /^[^:]+:/, the resulting path is
absolute.
- 7.
- Passing an empty string "" as the first argument to
"catdir()" is like passing"File::Spec->rootdir()"
as the first argument, i.e.
catdir("","a","b") is the same as
catdir(rootdir(),"a","b").
This is true on Unix, where
"catdir("","a","b")" yields
"/a/b" and "rootdir()" is "/". Note that
"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.
- 8.
- 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:
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:")
However, this approach is limited to the first arguments following
"root" (again, see "Unix->canonpath()" ). If there
are more arguments that move up the directory tree, an invalid path going
beyond root can be created.
As you've seen, you can force "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 "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
"catdir()" is still suitable for the concatenation of
directory
names, you are encouraged to use "catpath()" to concatenate
volume names and
directory paths. E.g.
$dir = File::Spec->catdir("tmp","sources");
$abs_path = File::Spec->catpath("MacintoshHD:", $dir,"");
yields
"MacintoshHD:tmp:sources:" .
- catfile
- Concatenate one or more directory names and a filename to form a complete
path ending with a filename. Resulting paths are relative by
default, but can be forced to be absolute (but avoid this).
IMPORTANT NOTE: Beginning with version 1.3 of this module, the
resulting path is relative by default and not absolute. This
decision was made due to portability reasons. Since
"File::Spec->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
"catfile()" uses "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"
but
catfile("","") = rootdir() # (e.g. "HD:")
catfile("","file") = rootdir() . file # (e.g. "HD:file")
catfile("HD:","file") = "HD:file"
This means that "catdir()" is called only when there are two or
more arguments, 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 volume names, directory paths and
filenames, you are encouraged to use "catpath()" (see
below).
- curdir
- Returns a string representing the current directory. On Mac OS, this is
":".
- devnull
- Returns a string representing the null device. On Mac OS, this is
"Dev:Null".
- rootdir
- 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. 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.
- 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.
- updir
- Returns a string representing the parent directory. On Mac OS, this is
"::".
- file_name_is_absolute
- 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)
- 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 $ENV{Commands} suitably split, as is done in
:lib:ExtUtils:MM_Mac.pm.
- splitpath
-
($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 without a leading ":". Empty
portions are returned as empty string ''.
The results can be passed to "catpath()" to get back a path
equivalent to (usually identical to) the original path.
- splitdir
- The opposite of "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
"splitpath()" otherwise.
Unlike just splitting the directories on the separator, empty directory
names ("") can be returned. Since "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", "::")
- 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 ':'.
- 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
"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
"rel2abs()". This means that it is taken to be relative to the
current working directory.
Based on code written by Shigio Yamaguchi.
- 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 "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.
AUTHORS¶
See the authors list in
File::Spec. Mac OS support by Paul Schinder
<schinder@pobox.com> and Thomas Wegner <wegner_thomas@yahoo.com>.
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.
SEE ALSO¶
See File::Spec and File::Spec::Unix. This package overrides the implementation
of these methods, not the semantics.