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=head1 NAME

Cache::File::Entry - An entry in the file based implementation of Cache

=head1 SYNOPSIS

  See 'Cache::Entry' for a synopsis.

=head1 DESCRIPTION

This module implements a version of Cache::Entry for the Cache::File variant
of Cache.  It should not be created or used directly, please see
'Cache::File' or 'Cache::Entry' instead.

=cut
package Cache::File::Entry;

require 5.006;
use strict;
use warnings;
use Cache::File;
use File::Spec;
use File::Path;
use File::Temp qw(tempfile);
use Fcntl qw(LOCK_EX LOCK_SH LOCK_NB);
use File::NFSLock;
use Symbol ();
use Carp;

use base qw(Cache::Entry);
use fields qw(dir path lockdetails);

our $VERSION = '2.11';

# hash of locks held my the process, keyed on path.  This is useful for
# catching potential deadlocks and warning the user, and for implementing
# LOCK_NONE (which still needs to do some synchronization).  Each entry will
# be an hash of { lock, type, count, lock, lockfh, linkcount }.  The
# filehandle and link count is for checking when the lock has been released by
# another process.
my %PROCESS_LOCKS;


sub new {
    my Cache::File::Entry $self = shift;

    $self = fields::new($self) unless ref $self;
    $self->SUPER::new(@_);

    # get file path and store full path and containing directory
    my ($dir, $file) = $self->{cache}->cache_file_path($self->{key});

    $self->{dir} = $dir;
    $self->{path} = File::Spec->catfile($dir, $file);

    return $self;
}

sub exists {
    my Cache::File::Entry $self = shift;

    # ensure pending expiries are removed
    $self->{cache}->purge();

    return -e $self->{path};
}

sub _set {
    my Cache::File::Entry $self = shift;
    my ($data, $expiry) = @_;

    $self->_make_path() or return;

    my ($fh, $filename) = tempfile('.XXXXXXXX', DIR => $self->{dir});
    binmode $fh;
    print $fh $data;
    close($fh);

    my $time = time();
    my $cache = $self->{cache};
    my $key = $self->{key};

    # lock indexes
    $cache->lock();

    my $exists = -e $self->{path};
    my $orig_size;

    unless ($exists) {
        # we're creating the entry
        $cache->create_entry($key, $time);
        $cache->change_count(1);
        $orig_size = 0;
    }
    # only remove current size if there is no active write handle
    elsif ($self->_trylock(LOCK_SH)) {
        $orig_size = $self->size();