File Coverage

blib/lib/File/Tail/Inotify2.pm

Criterion	Covered	Total	%
statement	61	64	95.3
branch	13	18	72.2
condition	6	15	40.0
subroutine	15	16	93.7
pod	2	2	100.0
total	97	115	84.3

package File::Tail::Inotify2;

use 5.008008;
use strict;
use warnings;
use Linux::Inotify2;
use File::Basename qw(dirname);
use Fcntl qw(SEEK_SET SEEK_END);
use Carp ();

our $VERSION = '1.00';

use constant {
    FMASK => IN_MODIFY | IN_MOVE_SELF,
    DMASK => IN_CREATE | IN_MOVED_FROM,
};

sub new {
    my $class = shift;
    my %args  = (
        file    => undef,
        on_read => undef,
        @_,
    );

    for (qw(file on_read)) {
        Carp::croak "Mandatory parameter $_ was missing."
            unless $args{$_};
    }

    unless ( ref $args{on_read} && ref $args{on_read} eq 'CODE' ) {
        Carp::croak "on_read must be CODE";
    }

    my $inotify = Linux::Inotify2->new
        or Carp::croak "Cannot create Inotify2 object: $!";

    my $self = bless {
        file    => $args{file},
        on_read => $args{on_read},
        curpos  => 0,
        in_move => 0,
        inotify => $inotify,
        },
        ref $class || $class;

    $self->_set_watcher;

    return $self;
}

sub poll {
    my $self = shift;
    1 while $self->{inotify}->poll || $self->{in_move};
}

sub _set_watcher {
    my $self = shift;
    $self->_set_file_watcher;
    $self->_set_dir_watcher;
}

sub _set_file_watcher {
    my $self = shift;
    my $size = (stat $self->{file})[7];
    $self->{curpos} = $size;
    $self->{inotify}->watch( $self->{file}, FMASK, $self->_in_modify );
}

sub _in_modify {
    my $self = shift;
    return sub {
        my $event = shift;
        if ( $event->IN_MODIFY ) {
            open my $fh, '<', $event->fullname
                or Carp::croak "Cannot open " . $event->fullname . ": $!";
            seek $fh, $self->{curpos}, SEEK_SET;

            while (<$fh>) {
                $self->{on_read}->($_);
            }

            $self->{curpos} = tell $fh;
            close $fh
                or Carp::croak "Cannot close " . $event->fullname . ": $!";
        }
        if ( $event->IN_MOVE_SELF ) {
            $event->w->cancel;
        }
    };
}

sub _set_dir_watcher {
    my $self = shift;
    $self->{inotify}->watch(
        dirname( $self->{file} ),
        DMASK,
        sub {
            my $event = shift;
            if ( $event->IN_MOVED_FROM && $event->fullname eq $self->{file} ) {
                $self->{in_move} = 1;
            }
            if ( $event->IN_CREATE && $event->fullname eq $self->{file} ) {
                $self->{curpos} = (stat $event->fullname)[7];
                $self->_set_file_watcher;
                $self->{in_move} = 0;
            }
        }
    );
}

1;
__END__