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package VCP::RefCountedFile;
=head1 NAME
VCP::RefCountedFile - An object that deletes a named file when nothing refers to it any more.
=head1 SYNOPSIS
use VCP::RefCountedFile;
{
my $fn = VCP::RefCountedFile->new( "/path/to/name" );
print $fn;
} ## "name" is deleted here.
=head1 DESCRIPTION
An object that mimics a string, but which refers to a file and deletes the
file when the last reference to the file via such objects disappears.
=cut
$VERSION = 1;
use strict ;
use Carp ;
use overload (
'""' => \&as_string,
'cmp' => sub {
"$_[0]" cmp "$_[1]"
},
);
use VCP::Debug ':debug' ;
use VCP::Logger qw( pr );
use VCP::Utils 'empty' ;
sub new {
my $class = ref $_[0] ? ref shift : shift;
my $self = bless \my( $value ), $class;
$self->set( @_ ) if @_;
return $self;
}
sub as_string {
my $self = shift;
return $$self;
}
my %ref_counts;
## Each file gets a ref count. This hash maintains that ref_count.
sub set {
my $self = shift;
my ( $value ) = @_;
if ( !empty( $$self ) ) {
my $fn = "$$self"; ## for simplicity
if (
$ref_counts{$fn}
&& --$ref_counts{$fn} < 1
&& -e $fn
) {
if ( debugging ) {
my @details ;
my $i = 2 ;
do { @details = caller($i++) } until $details[0] ne __PACKAGE__ ;
debug "$self unlinking '$fn' in " . join( '|', @details[0,1,2,3]) ;
}
unlink $fn or pr "$! unlinking $fn\n"
}
}
$$self = $value;
++$ref_counts{$$self} unless empty $$self;
}
END {
if ( debugging && ! $ENV{VCPNODELETE} ) {
for ( sort keys %ref_counts ) {
if ( -e $_ ) {
pr "$_ not deleted" ;
}
}
}
}
sub DESTROY {
return if $ENV{VCPNODELETE};
my $self = shift ;
$self->set( undef );
}
=head1 SUBCLASSING
This class is a bless scalar.
=head1 COPYRIGHT
Copyright 2000, Perforce Software, Inc. All Rights Reserved.
This module and the VCP package are licensed according to the terms given in
the file LICENSE accompanying this distribution, a copy of which is included in
L<vcp>.
=head1 AUTHOR
Barrie Slaymaker <barries@slaysys.com>
=cut
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