Path::Class::File::Stat(3pm) User Contributed Perl Documentation Path::Class::File::Stat(3pm)NAME
Path::Class::File::Stat - cache and compare stat() calls on a Path::Class::File object
SYNOPSIS
use Path::Class::File::Stat;
my $file = Path::Class::File::Stat->new('path','to','file');
# $file has all the magic of Path::Class::File
# sometime later
if ($file->changed)
{
# do something provocative
}
DESCRIPTION
Path::Class::File::Stat is a simple extension of Path::Class::File. Path::Class::File::Stat is useful in long-running programs (as under
mod_perl) where you might have a file handle opened and want to check if the underlying file has changed.
METHODS
Path::Class::File::Stat extends Path::Class::File objects in the following ways.
use_md5
Calling this method will attempt to load Digest::MD5 and use that instead of stat() for creating file signatures. This is similar to how
File::Modified works.
changed
Returns the previously cached File::stat object if the file's device number and inode number have changed, or if the modification time or
size has changed.
Returns 0 (false) otherwise.
While File::Modified uses a MD5 signature of the stat() of a file to determine if the file has changed, changed() uses a simpler (and
probably more naive) algorithm. If you need a more sophisticated way of determining if a file has changed, use the restat() method and
compare the cached File::stat object it returns with the current File::stat object.
Example of your own changed() logic:
my $oldstat = $file->restat;
my $newstat = $file->stat;
# compare $oldstat and $newstat any way you like
Or just use File::Modified instead.
restat
Re-cache the File::stat object in the Path::Class::File::Stat object. Returns the previously cached File::stat object.
The changed() method calls this method internally if changed() is going to return true.
SEE ALSO
Path::Class, Path::Class::File, File::Signature, File::Modified
AUTHOR
Peter Karman, <karman@cpan.org>
COPYRIGHT AND LICENSE
Copyright (C) 2006 by Peter Karman
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
perl v5.14.2 2012-01-28 Path::Class::File::Stat(3pm)
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Path::Class(3pm) User Contributed Perl Documentation Path::Class(3pm)NAME
Path::Class - Cross-platform path specification manipulation
VERSION
version 0.26
SYNOPSIS
use Path::Class;
my $dir = dir('foo', 'bar'); # Path::Class::Dir object
my $file = file('bob', 'file.txt'); # Path::Class::File object
# Stringifies to 'foo/bar' on Unix, 'fooar' on Windows, etc.
print "dir: $dir
";
# Stringifies to 'bob/file.txt' on Unix, 'bobfile.txt' on Windows
print "file: $file
";
my $subdir = $dir->subdir('baz'); # foo/bar/baz
my $parent = $subdir->parent; # foo/bar
my $parent2 = $parent->parent; # foo
my $dir2 = $file->dir; # bob
# Work with foreign paths
use Path::Class qw(foreign_file foreign_dir);
my $file = foreign_file('Mac', ':foo:file.txt');
print $file->dir; # :foo:
print $file->as_foreign('Win32'); # foofile.txt
# Interact with the underlying filesystem:
# $dir_handle is an IO::Dir object
my $dir_handle = $dir->open or die "Can't read $dir: $!";
# $file_handle is an IO::File object
my $file_handle = $file->open($mode) or die "Can't read $file: $!";
DESCRIPTION
"Path::Class" is a module for manipulation of file and directory specifications (strings describing their locations, like
'/home/ken/foo.txt' or 'C:WindowsFoo.txt') in a cross-platform manner. It supports pretty much every platform Perl runs on, including
Unix, Windows, Mac, VMS, Epoc, Cygwin, OS/2, and NetWare.
The well-known module "File::Spec" also provides this service, but it's sort of awkward to use well, so people sometimes avoid it, or use
it in a way that won't actually work properly on platforms significantly different than the ones they've tested their code on.
In fact, "Path::Class" uses "File::Spec" internally, wrapping all the unsightly details so you can concentrate on your application code.
Whereas "File::Spec" provides functions for some common path manipulations, "Path::Class" provides an object-oriented model of the world of
path specifications and their underlying semantics. "File::Spec" doesn't create any objects, and its classes represent the different ways
in which paths must be manipulated on various platforms (not a very intuitive concept). "Path::Class" creates objects representing files
and directories, and provides methods that relate them to each other. For instance, the following "File::Spec" code:
my $absolute = File::Spec->file_name_is_absolute(
File::Spec->catfile( @dirs, $file )
);
can be written using "Path::Class" as
my $absolute = Path::Class::File->new( @dirs, $file )->is_absolute;
or even as
my $absolute = file( @dirs, $file )->is_absolute;
Similar readability improvements should happen all over the place when using "Path::Class".
Using "Path::Class" can help solve real problems in your code too - for instance, how many people actually take the "volume" (like "C:" on
Windows) into account when writing "File::Spec"-using code? I thought not. But if you use "Path::Class", your file and directory objects
will know what volumes they refer to and do the right thing.
The guts of the "Path::Class" code live in the "Path::Class::File" and "Path::Class::Dir" modules, so please see those modules'
documentation for more details about how to use them.
EXPORT
The following functions are exported by default.
file
A synonym for "Path::Class::File->new".
dir A synonym for "Path::Class::Dir->new".
If you would like to prevent their export, you may explicitly pass an empty list to perl's "use", i.e. "use Path::Class ()".
The following are exported only on demand.
foreign_file
A synonym for "Path::Class::File->new_foreign".
foreign_dir
A synonym for "Path::Class::Dir->new_foreign".
Notes on Cross-Platform Compatibility
Although it is much easier to write cross-platform-friendly code with this module than with "File::Spec", there are still some issues to be
aware of.
o On some platforms, notably VMS and some older versions of DOS (I think), all filenames must have an extension. Thus if you create a
file called foo/bar and then ask for a list of files in the directory foo, you may find a file called bar. instead of the bar you were
expecting. Thus it might be a good idea to use an extension in the first place.
AUTHOR
Ken Williams, KWILLIAMS@cpan.org
COPYRIGHT
Copyright (c) Ken Williams. All rights reserved.
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
SEE ALSO
Path::Class::Dir, Path::Class::File, File::Spec
perl v5.14.2 2012-06-15 Path::Class(3pm)