Path::Class::Dir(3) User Contributed Perl Documentation Path::Class::Dir(3)NAMEPath::Class::Dir - Objects representing directories
VERSION
version 0.25
SYNOPSIS
use Path::Class qw(dir); # Export a short constructor
my $dir = dir('foo', 'bar'); # Path::Class::Dir object
my $dir = Path::Class::Dir->new('foo', 'bar'); # Same thing
# Stringifies to 'foo/bar' on Unix, 'foo\bar' on Windows, etc.
print "dir: $dir\n";
if ($dir->is_absolute) { ... }
if ($dir->is_relative) { ... }
my $v = $dir->volume; # Could be 'C:' on Windows, empty string
# on Unix, 'Macintosh HD:' on Mac OS
$dir->cleanup; # Perform logical cleanup of pathname
$dir->resolve; # Perform physical cleanup of pathname
my $file = $dir->file('file.txt'); # A file in this directory
my $subdir = $dir->subdir('george'); # A subdirectory
my $parent = $dir->parent; # The parent directory, 'foo'
my $abs = $dir->absolute; # Transform to absolute path
my $rel = $abs->relative; # Transform to relative path
my $rel = $abs->relative('/foo'); # Relative to /foo
print $dir->as_foreign('Mac'); # :foo:bar:
print $dir->as_foreign('Win32'); # foo\bar
# Iterate with IO::Dir methods:
my $handle = $dir->open;
while (my $file = $handle->read) {
$file = $dir->file($file); # Turn into Path::Class::File object
...
}
# Iterate with Path::Class methods:
while (my $file = $dir->next) {
# $file is a Path::Class::File or Path::Class::Dir object
...
}
DESCRIPTION
The "Path::Class::Dir" class contains functionality for manipulating
directory names in a cross-platform way.
METHODS
$dir = Path::Class::Dir->new( <dir1>, <dir2>, ... )
$dir = dir( <dir1>, <dir2>, ... )
Creates a new "Path::Class::Dir" object and returns it. The
arguments specify names of directories which will be joined to
create a single directory object. A volume may also be specified
as the first argument, or as part of the first argument. You can
use platform-neutral syntax:
my $dir = dir( 'foo', 'bar', 'baz' );
or platform-native syntax:
my $dir = dir( 'foo/bar/baz' );
or a mixture of the two:
my $dir = dir( 'foo/bar', 'baz' );
All three of the above examples create relative paths. To create
an absolute path, either use the platform native syntax for doing
so:
my $dir = dir( '/var/tmp' );
or use an empty string as the first argument:
my $dir = dir( '', 'var', 'tmp' );
If the second form seems awkward, that's somewhat intentional -
paths like "/var/tmp" or "\Windows" aren't cross-platform concepts
in the first place (many non-Unix platforms don't have a notion of
a "root directory"), so they probably shouldn't appear in your code
if you're trying to be cross-platform. The first form is perfectly
natural, because paths like this may come from config files, user
input, or whatever.
As a special case, since it doesn't otherwise mean anything useful
and it's convenient to define this way, "Path::Class::Dir->new()"
(or "dir()") refers to the current directory
("File::Spec->curdir"). To get the current directory as an
absolute path, do "dir()->absolute".
Finally, as another special case "dir(undef)" will return undef,
since that's usually an accident on the part of the caller, and
returning the root directory would be a nasty surprise just asking
for trouble a few lines later.
$dir->stringify
This method is called internally when a "Path::Class::Dir" object
is used in a string context, so the following are equivalent:
$string = $dir->stringify;
$string = "$dir";
$dir->volume
Returns the volume (e.g. "C:" on Windows, "Macintosh HD:" on Mac
OS, etc.) of the directory object, if any. Otherwise, returns the
empty string.
$dir->is_dir
Returns a boolean value indicating whether this object represents a
directory. Not surprisingly, "Path::Class::File" objects always
return false, and "Path::Class::Dir" objects always return true.
$dir->is_absolute
Returns true or false depending on whether the directory refers to
an absolute path specifier (like "/usr/local" or "\Windows").
$dir->is_relative
Returns true or false depending on whether the directory refers to
a relative path specifier (like "lib/foo" or "./dir").
$dir->cleanup
Performs a logical cleanup of the file path. For instance:
my $dir = dir('/foo//baz/./foo')->cleanup;
# $dir now represents '/foo/baz/foo';
$dir->resolve
Performs a physical cleanup of the file path. For instance:
my $dir = dir('/foo//baz/../foo')->resolve;
# $dir now represents '/foo/foo', assuming no symlinks
This actually consults the filesystem to verify the validity of the
path.
$file = $dir->file( <dir1>, <dir2>, ..., <file> )
Returns a "Path::Class::File" object representing an entry in $dir
or one of its subdirectories. Internally, this just calls
"Path::Class::File->new( @_ )".
$subdir = $dir->subdir( <dir1>, <dir2>, ... )
Returns a new "Path::Class::Dir" object representing a subdirectory
of $dir.
$parent = $dir->parent
Returns the parent directory of $dir. Note that this is the
logical parent, not necessarily the physical parent. It really
means we just chop off entries from the end of the directory list
until we cain't chop no more. If the directory is relative, we
start using the relative forms of parent directories.
The following code demonstrates the behavior on absolute and
relative directories:
$dir = dir('/foo/bar');
for (1..6) {
print "Absolute: $dir\n";
$dir = $dir->parent;
}
$dir = dir('foo/bar');
for (1..6) {
print "Relative: $dir\n";
$dir = $dir->parent;
}
########### Output on Unix ################
Absolute: /foo/bar
Absolute: /foo
Absolute: /
Absolute: /
Absolute: /
Absolute: /
Relative: foo/bar
Relative: foo
Relative: .
Relative: ..
Relative: ../..
Relative: ../../..
@list = $dir->children
Returns a list of "Path::Class::File" and/or "Path::Class::Dir"
objects listed in this directory, or in scalar context the number
of such objects. Obviously, it is necessary for $dir to exist and
be readable in order to find its children.
Note that the children are returned as subdirectories of $dir, i.e.
the children of foo will be foo/bar and foo/baz, not bar and baz.
Ordinarily "children()" will not include the self and parent
entries "." and ".." (or their equivalents on non-Unix systems),
because that's like I'm-my-own-grandpa business. If you do want
all directory entries including these special ones, pass a true
value for the "all" parameter:
@c = $dir->children(); # Just the children
@c = $dir->children(all => 1); # All entries
In addition, there's a "no_hidden" parameter that will exclude all
normally "hidden" entries - on Unix this means excluding all
entries that begin with a dot ("."):
@c = $dir->children(no_hidden => 1); # Just normally-visible entries
$abs = $dir->absolute
Returns a "Path::Class::Dir" object representing $dir as an
absolute path. An optional argument, given as either a string or a
"Path::Class::Dir" object, specifies the directory to use as the
base of relativity - otherwise the current working directory will
be used.
$rel = $dir->relative
Returns a "Path::Class::Dir" object representing $dir as a relative
path. An optional argument, given as either a string or a
"Path::Class::Dir" object, specifies the directory to use as the
base of relativity - otherwise the current working directory will
be used.
$boolean = $dir->subsumes($other)
Returns true if this directory spec subsumes the other spec, and
false otherwise. Think of "subsumes" as "contains", but we only
look at the specs, not whether $dir actually contains $other on the
filesystem.
The $other argument may be a "Path::Class::Dir" object, a
"Path::Class::File" object, or a string. In the latter case, we
assume it's a directory.
# Examples:
dir('foo/bar' )->subsumes(dir('foo/bar/baz')) # True
dir('/foo/bar')->subsumes(dir('/foo/bar/baz')) # True
dir('foo/bar' )->subsumes(dir('bar/baz')) # False
dir('/foo/bar')->subsumes(dir('foo/bar')) # False
$boolean = $dir->contains($other)
Returns true if this directory actually contains $other on the
filesystem. $other doesn't have to be a direct child of $dir, it
just has to be subsumed.
$foreign = $dir->as_foreign($type)
Returns a "Path::Class::Dir" object representing $dir as it would
be specified on a system of type $type. Known types include
"Unix", "Win32", "Mac", "VMS", and "OS2", i.e. anything for which
there is a subclass of "File::Spec".
Any generated objects (subdirectories, files, parents, etc.) will
also retain this type.
$foreign = Path::Class::Dir->new_foreign($type, @args)
Returns a "Path::Class::Dir" object representing $dir as it would
be specified on a system of type $type. Known types include
"Unix", "Win32", "Mac", "VMS", and "OS2", i.e. anything for which
there is a subclass of "File::Spec".
The arguments in @args are the same as they would be specified in
"new()".
@list = $dir->dir_list([OFFSET, [LENGTH]])
Returns the list of strings internally representing this directory
structure. Each successive member of the list is understood to be
an entry in its predecessor's directory list. By contract,
"Path::Class->new( $dir->dir_list )" should be equivalent to $dir.
The semantics of this method are similar to Perl's "splice" or
"substr" functions; they return "LENGTH" elements starting at
"OFFSET". If "LENGTH" is omitted, returns all the elements
starting at "OFFSET" up to the end of the list. If "LENGTH" is
negative, returns the elements from "OFFSET" onward except for
"-LENGTH" elements at the end. If "OFFSET" is negative, it counts
backward "OFFSET" elements from the end of the list. If "OFFSET"
and "LENGTH" are both omitted, the entire list is returned.
In a scalar context, "dir_list()" with no arguments returns the
number of entries in the directory list; "dir_list(OFFSET)" returns
the single element at that offset; "dir_list(OFFSET, LENGTH)"
returns the final element that would have been returned in a list
context.
$fh = $dir->open()
Passes $dir to "IO::Dir->open" and returns the result as an
"IO::Dir" object. If the opening fails, "undef" is returned and $!
is set.
$dir->mkpath($verbose, $mode)
Passes all arguments, including $dir, to "File::Path::mkpath()" and
returns the result (a list of all directories created).
$dir->rmtree($verbose, $cautious)
Passes all arguments, including $dir, to "File::Path::rmtree()" and
returns the result (the number of files successfully deleted).
$dir->remove()
Removes the directory, which must be empty. Returns a boolean
value indicating whether or not the directory was successfully
removed. This method is mainly provided for consistency with
"Path::Class::File"'s "remove()" method.
$dir->tempfile(...)
An interface to "File::Temp"'s "tempfile()" function. Just like
that function, if you call this in a scalar context, the return
value is the filehandle and the file is "unlink"ed as soon as
possible (which is immediately on Unix-like platforms). If called
in a list context, the return values are the filehandle and the
filename.
The given directory is passed as the "DIR" parameter.
Here's an example of pretty good usage which doesn't allow race
conditions, won't leave yucky tempfiles around on your filesystem,
etc.:
my $fh = $dir->tempfile;
print $fh "Here's some data...\n";
seek($fh, 0, 0);
while (<$fh>) { do something... }
Or in combination with a "fork":
my $fh = $dir->tempfile;
print $fh "Here's some more data...\n";
seek($fh, 0, 0);
if ($pid=fork()) {
wait;
} else {
something($_) while <$fh>;
}
$dir_or_file = $dir->next()
A convenient way to iterate through directory contents. The first
time "next()" is called, it will "open()" the directory and read
the first item from it, returning the result as a
"Path::Class::Dir" or "Path::Class::File" object (depending, of
course, on its actual type). Each subsequent call to "next()" will
simply iterate over the directory's contents, until there are no
more items in the directory, and then the undefined value is
returned. For example, to iterate over all the regular files in a
directory:
while (my $file = $dir->next) {
next unless -f $file;
my $fh = $file->open('r') or die "Can't read $file: $!";
...
}
If an error occurs when opening the directory (for instance, it
doesn't exist or isn't readable), "next()" will throw an exception
with the value of $!.
$dir->traverse( sub { ... }, @args )
Calls the given callback for the root, passing it a continuation
function which, when called, will call this recursively on each of
its children. The callback function should be of the form:
sub {
my ($child, $cont, @args) = @_;
# ...
}
For instance, to calculate the number of files in a directory, you
can do this:
my $nfiles = $dir->traverse(sub {
my ($child, $cont) = @_;
return sum($cont->(), ($child->is_dir ? 0 : 1));
});
or to calculate the maximum depth of a directory:
my $depth = $dir->traverse(sub {
my ($child, $cont, $depth) = @_;
return max($cont->($depth + 1), $depth);
}, 0);
You can also choose not to call the callback in certain situations:
$dir->traverse(sub {
my ($child, $cont) = @_;
return if -l $child; # don't follow symlinks
# do something with $child
return $cont->();
});
$dir->recurse( callback => sub {...} )
Iterates through this directory and all of its children, and all of
its children's children, etc., calling the "callback" subroutine
for each entry. This is a lot like what the "File::Find" module
does, and of course "File::Find" will work fine on "Path::Class"
objects, but the advantage of the "recurse()" method is that it
will also feed your callback routine "Path::Class" objects rather
than just pathname strings.
The "recurse()" method requires a "callback" parameter specifying
the subroutine to invoke for each entry. It will be passed the
"Path::Class" object as its first argument.
"recurse()" also accepts two boolean parameters, "depthfirst" and
"preorder" that control the order of recursion. The default is a
preorder, breadth-first search, i.e. "depthfirst => 0, preorder =>
1". At the time of this writing, all combinations of these two
parameters are supported except "depthfirst => 0, preorder => 0".
$st = $file->stat()
Invokes "File::stat::stat()" on this directory and returns a
"File::stat" object representing the result.
$st = $file->lstat()
Same as "stat()", but if $file is a symbolic link, "lstat()" stats
the link instead of the directory the link points to.
$class = $file->file_class()
Returns the class which should be used to create file objects.
Generally overridden whenever this class is subclassed.
AUTHOR
Ken Williams, kwilliams@cpan.org
SEE ALSO
Path::Class, Path::Class::File, File::Spec
perl v5.14.2 2012-02-16 Path::Class::Dir(3)
