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|
#-*- perl -*-
#
# Copyright (C) 2000,2001,2002,2003 Ken'ichi Fukamachi
#
# $FML: SimpleLock.pm,v 1.17 2003/01/11 15:14:23 fukachan Exp $
#
package File::SimpleLock;
use vars qw(%LockedFileHandle %FileIsLocked @ISA $Error);
use strict;
use Carp;
use ErrorStatus qw(error_set error error_clear);
#
# XXX-TODO: merge this module into IO::Adapter.
#
=head1 NAME
File::SimpleLock - simple lock by flock(2)
=head1 SYNOPSIS
use File::SimpleLock;
my $lockobj = new File::SimpleLock;
$lockobj->lock( { file => $lock_file } ) || croak "fail to lock";
... do someting under locking ...
$lockobj->unlock( { file => $lock_file } ) || croak "fail to unlock";
=head1 DESCRIPTION
File::SimpleLock module provides simple lock using flock(2).
=head1 METHODS
=head2 C<lock($args)>
flock(2) for $args->{ file };
=head2 C<unlock($args)>
unlock flock(2) for $args->{ file };
=cut
use Fcntl qw(:DEFAULT :flock);
# Descriptions: standard constructor.
# Arguments: OBJ($self)
# Side Effects: none
# Return Value: OBJ
sub new
{
my ($self) = @_;
my ($type) = ref($self) || $self;
my $me = {};
return bless $me, $type;
}
# Descriptions: lock
# Arguments: OBJ($self) HASH_REF($args)
# Side Effects: none
# Return Value: 1 or 0
sub lock
{
my ($self, $args) = @_;
my $file = $args->{ file };
$self->_simple_flock($file);
}
# Descriptions: unlock
# Arguments: OBJ($self) HASH_REF($args)
# Side Effects: none
# Return Value: 1 or 0
sub unlock
{
my ($self, $args) = @_;
my $file = $args->{ file };
$self->_simple_funlock($file);
}
# Descriptions: try flock(2) for $file
# Arguments: OBJ($self) STR($file)
# Side Effects: flock for $file
# Return Value: 1 or 0
sub _simple_flock
{
my ($self, $file) = @_;
use FileHandle;
my $fh = new FileHandle ">> $file";
if (defined $fh) {
$LockedFileHandle{ $file } = $fh;
my $r = 0; # return value
eval q{
$r = flock($fh, &LOCK_EX);
};
$self->error_set($@) if $@;
if ($r) {
$FileIsLocked{ $file } = 1;
return 1;
}
}
else {
$self->error_set("cannot open $file");
}
return 0;
}
# Descriptions: try unlock by flock(2) for $file
# Arguments: OBJ($self) STR($file)
# Side Effects: flock for $file
# Return Value: 1 or 0
sub _simple_funlock
{
my ($self, $file) = @_;
return 0 unless $FileIsLocked{ $file };
return 0 unless $LockedFileHandle{ $file };
my $fh = $LockedFileHandle{ $file };
my $r = 0; # return value
eval q{
$r = flock($fh, &LOCK_UN);
};
$self->error_set($@) if $@;
if ($r) {
delete $FileIsLocked{ $file };
delete $LockedFileHandle{ $file };
return 1;
}
return 0;
}
=head1 SEE ALSO
L<FileHandle>,
L<ErrorStatus>,
=head1 CODING STYLE
See C<http://www.fml.org/software/FNF/> on fml coding style guide.
=head1 AUTHOR
Ken'ichi Fukamachi <F<fukachan@fml.org>>
=head1 COPYRIGHT
Copyright (C) 2000,2001,2002,2003 Ken'ichi Fukamachi
All rights reserved. This program is free software; you can
redistribute it and/or modify it under the same terms as Perl itself.
=head1 HISTORY
File::SimpleLock first appeared in fml8 mailing list driver package.
See C<http://www.fml.org/> for more details.
=cut
1;
|
