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#  You may distribute under the terms of either the GNU General Public License
#  or the Artistic License (the same terms as Perl itself)
#
#  (C) Paul Evans, 2012-2015 -- leonerd@leonerd.org.uk

package IO::Async::File;

use strict;
use warnings;

our $VERSION = '0.70';

use base qw( IO::Async::Timer::Periodic );

use Carp;
use File::stat;

# No point watching blksize or blocks
my @STATS = qw( dev ino mode nlink uid gid rdev size atime mtime ctime );

=head1 NAME

C<IO::Async::File> - watch a file for changes

=head1 SYNOPSIS

 use IO::Async::File;

 use IO::Async::Loop;
 my $loop = IO::Async::Loop->new;

 my $file = IO::Async::File->new(
    filename => "config.ini",
    on_mtime_changed => sub {
       my ( $self ) = @_;
       print STDERR "Config file has changed\n";
       reload_config( $self->handle );
    }
 );

 $loop->add( $file );

 $loop->run;

=head1 DESCRIPTION

This subclass of L<IO::Async::Notifier> watches an open filehandle or named
filesystem entity for changes in its C<stat()> fields. It invokes various
events when the values of these fields change. It is most often used to watch
a file for size changes; for this task see also L<IO::Async::FileStream>.

While called "File", it is not required that the watched filehandle be a
regular file. It is possible to watch anything that C<stat(2)> may be called
on, such as directories or other filesystem entities.

=cut

=head1 EVENTS

The following events are invoked, either using subclass methods or CODE
references in parameters.

=head2 on_dev_changed $new_dev, $old_dev

=head2 on_ino_changed $new_ino, $old_ino

=head2 ...

=head2 on_ctime_changed $new_ctime, $old_ctime

Invoked when each of the individual C<stat()> fields have changed. All the
C<stat()> fields are supported apart from C<blocks> and C<blksize>. Each is
passed the new and old values of the field.

=head2 on_devino_changed $new_stat, $old_stat

Invoked when either of the C<dev> or C<ino> fields have changed. It is passed
two L<File::stat> instances containing the complete old and new C<stat()>
fields. This can be used to observe when a named file is renamed; it will not