Path::Class::File::Stat(3) test whether the file beneath a Path::Class::File object has changed


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


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.


Path::Class::File::Stat extends Path::Class::File objects in the following ways.


Calling this method will attempt to load Digest::MD5 and use that in addition to stat() for creating file signatures. This is similar to how File::Modified works.


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, or if use_md5() is on, the MD5 signature of the file's contents 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.


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.


Peter Karman, <[email protected]>


Copyright (C) 2006, 2013 by Peter Karman

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