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#-*- perl -*-
#
# Copyright (C) 2001,2002 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.
#
# $FML: Rotate.pm,v 1.12 2002/09/22 14:56:57 fukachan Exp $
#
package File::Rotate;
use strict;
use vars qw(@ISA @EXPORT @EXPORT_OK);
use Carp;
BEGIN {}
END {}
=head1 NAME
File::Rotate - file rotatation utilities
=head1 SYNOPSIS
$obj = new File::Rotate {
max_size => 10000,
num_backlog => 4,
};
$obj->rotate( \@target_files );
=head1 DESCRIPTION
Utility functions for file rotate operations.
It turns over the given C<file> by some condition.
Typical condition is given as the number of files or how old they are.
C<rotation> renames and rearranges files like this:
rm file.4
mv file.3 file.4
mv file.2 file.3
mv file.1 file.2
mv file.0 file.1
mv file file.0
In old age, shell script does this but
in modern unix,
some programs such as /usr/bin/newsyslog (MIT athena project) do.
=head1 METHODS
=head2 new($args)
ordinary constructor. $args accpets the following parameters.
parameter default value
------------------------
max_size 300*1024
num_backlog 4
=cut
# Descriptions: constructor
# forward new() request to superclass (IO::File)
# Arguments: OBJ($self) HASH_REF($args)
# Side Effects: none
# Return Value: OBJ
sub new
{
my ($self, $args) = shift;
my ($type) = ref($self) || $self;
my $me = {};
if ( ref($args->{ file_list }) eq 'ARRAY' ) {
$me->{ _file_list } = $args->{ file_list };
}
$me->{ _max_size } = $args->{ max_size } || 300*1024;
$me->{ _num_backlog } = $args->{ num_backlog } || 4;
return bless $me, $type;
}
=head2 C<is_time_to_rotate()>
C<stat()> the file correspoinding to the object and
determine whether the time to do comes or not.
=cut
# Descriptions: determine the time to rotate
# Arguments: OBJ($self)
# Side Effects: none
# Return Value: 1 (time comes!) or 0
sub is_time_to_rotate
{
my ($self) = @_;
my ($file, $size, $max) = $self->_get_param();
use File::stat;
my $st = stat($file);
return 1 if $st->size > $size;
return 0;
}
=head2 C<rotate()>
rename files to rotate it.
rm file.4
mv file.3 file.4
mv file.2 file.3
mv file.1 file.2
mv file.0 file.1
mv file file.0
=cut
# Descriptions: rotate filenames
# Arguments: OBJ($self)
# Side Effects: filename rotations
# unlink the oldest file
# Return Value: none
sub rotate
{
my ($self) = @_;
my ($file, $size, $max) = $self->_get_param();
# remove oldest file
my $maxfile = $file.".".$max;
if (-f $maxfile) { unlink $maxfile;}
# mv var/log/file.3 -> var/log/file.4 ...;
do {
my $old = "$file.".($max - 1 > 0 ? $max - 1 : 0);
my $new = "$file.".($max);
print STDERR "rename($old, $new)" if -f $old;
-f $old && rename($old, $new);
$max--;
} while ($max > 0);
}
# Descriptions: extract parameters in $self
# Arguments: OBJ($self)
# Side Effects: none
# Return Value: ARRAY(file, max_size, num_backlog)
sub _get_param
{
my ($self) = @_;
(${*$self}{_file}, ${*$self}{_max_size}, ${*$self}{_num_backlog});
}
=head2 C<error()>
return the error message if exists.
=cut
# Descriptions: return error message
# Arguments: OBJ($self)
# XXX $self is blessed file handle.
# Side Effects: none
# Return Value: STR(error message)
sub error
{
my ($self) = @_;
my $fh = $self;
${ *$fh }{ _error };
}
=head1 CODING STYLE
See C<http://www.fml.org/software/FNF/> on fml coding style guide.
=head1 AUTHOR
Ken'ichi Fukamachi
=head1 COPYRIGHT
Copyright (C) 2001,2002 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::Rotate first appeared in fml8 mailing list driver package.
See C<http://www.fml.org/> for more details.
=cut
1;
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