Net::FTP::Versioning - Extends Net::FTP get() and put() methods to add versioning support to them

	use Net::FTP::Versioning;

	# Start your ftp connection as you do when using Net::FTP.
	$ftp = Net::FTP::Versioning->new("some.host.name", Debug => 0)
		or die "Cannot connect to some.host.name: $@";
	$ftp->login("anonymous",'-anonymous@')
		or die "Cannot login ", $ftp->message;
	$ftp->cwd("/pub")
		or die "Cannot change working directory ", $ftp->message;

	# Now, get the remote file but activate versioning support
	# so your local file (if it exists) will be rotated until
	# $NROTATIONS instead of being silently overwritten
	$NROTATIONS = 2;
	$ftp->get("that.file", versions => $NROTATIONS)
		or die "get failed ", $ftp->message;

	# Also, print the transfer time in seconds
	print "File transfered in: ", $ftp->transferTime(), "seconds.\n";

	$ftp->quit;

package Net::FTP::Versioning;
use strict;
require 5.001;
use Net::FTP;
use vars qw(@ISA $VERSION);
use Carp;
@ISA = ("Net::FTP");
$VERSION = "0.01";

sub new {
    my $classname  = shift;
    my $self       = $classname->SUPER::new(@_);
    $self->_init(@_);
    return $self;
}
sub _init {
    my $self = shift;
    ${*$self}->{net_ftp_versioning_transfertime} = undef;
}
sub _setTransferTime { # returns: nothing
	my $self = shift;
	${*$self}->{net_ftp_versioning_transfertime} = shift;
}
sub transferTime { # returns: Integer: the transfer time in seconds
	my $self = shift;
	my $seconds = ${*$self}->{net_ftp_versioning_transfertime};
	return ($seconds);
}
# put ( LOCAL_FILE [, REMOTE_FILE][, versions => N ] )
sub put {  # returns: what Net::FTP->put() returns
	my $self = shift;
	# checking if versionning is enabled
	my $versions = 0;
	my $end = $#_;	# last element's index of @_
	if (@_ >= 3 && $_[$end - 1] eq 'versions' ) { # versionning is enabled
		$versions = pop (@_);
		pop (@_); # to remove the "versions" element
		# defining the remote filename. the piece of code bellow
		# was cut-and-pasted from Net::FTP module.
		my($local,$remote) = @_;
		my $localfd = ref($local) || ref(\$local) eq "GLOB";
		unless(defined $remote){
	 		croak 'Must specify remote filename with stream input'
	        	if $localfd;
			require File::Basename;
	  		$remote = File::Basename::basename($local);
	 	}
	 	croak("Bad remote filename '$remote'\n")
        	if $remote =~ /[\r\n]/s;
        # end of cut-and-pasting
        
	 	# If $versions != 0, we set $remote to rotation in the remote
	 	# server. It only will be rotated if already exists a file with 
	 	# the same name as $remote.
	 	if ( $versions != 0 ) {
			$self->_rotate_file("remote", $remote, $versions);
		}
	}
    # Let's make the file transfer gathering the transfer time
    my ($t0,	# time before the transfer
		$t1		# time after the transfer
    );
    my $result = undef; # will store what Net::FTP->put() returns
    $t0 = time;
	$result = $self->SUPER::put(@_);
	$t1 = time;
	$self->_setTransferTime($t1 - $t0);
	return $result;
}
# get ( REMOTE_FILE [, LOCAL_FILE [, WHERE]][, versions => N])
sub get { # returns: what Net::FTP->get() returns
	my $self = shift;
	# checking if versionning is enabled
	my $versions = 0;
	my $end = $#_;	# last element's index of @_
	if (@_ >= 3 && $_[$end - 1] eq 'versions' ) { # versionning is enabled
		$versions = pop (@_);
		pop (@_); # to remove the "versions" element
		# defining the local filename as is done in Net::FTP module.
		my($remote, $local) = @_;
		my $localfd = ref($local) || ref(\$local) eq "GLOB";
		croak "Can't enable versioning if the local_file is a filehandle\n."
			if $localfd;
		($local = $remote) =~ s#^.*/## unless(defined $local);
 		croak("Bad remote filename '$remote'\n")
			if $remote =~ /[\r\n]/s;
		
	 	# If $versions != 0, we set $local to rotation in the localhost.
	 	# It only will be rotated if already exists a file with 
	 	# the same name as $remote.
	 	if ( $versions != 0 ) {
			$self->_rotate_file("local", $local, $versions);
		}
	}
    # Let's make the file transfer gathering the transfer time
    my ($t0,	# time before the transfer
		$t1		# time after the transfer
    );
    my $result = undef; # will store what Net::FTP->put() returns
    $t0 = time;
	$result = $self->SUPER::get(@_);
	$t1 = time;
	$self->_setTransferTime($t1 - $t0);
	return $result;
}

# rotates a filename. the file can be 'local' or 'remote'.
# _rotate_file (
#	'local' | 'remote', $filename,
#	$number_of_versions [, $counter]
# )
sub _rotate_file { # returns: nothing
	my $i;		# counter. on the first run it must be = 0
	$i = ( @_ == 5 ? pop (@_) : 0 );
	my ($self, $where, $file, $nversions) = @_;
	# Anonymous Subroutines ########################
	# All the anonymous subroutines bellow are available only inside 
	# _rotate_file() and they relly on $where and $self
	# variables set inside _rotate_file()
	my $exist = sub { # tells if the file exists
		my $file = shift;
		if ($where eq 'local') {
			return ( -f $file );
		} else { # remote file
			return $self->size($file);
		}
	};
	my $del = sub { # removes the file
		my $file = shift;
		if ($where eq 'local') {
			unlink ($file);
		} else { # remote file
			$self->delete($file);
		}
	};
	my $move = sub { # rename the file
		my ($oldName, $newName) = @_;
		if ($where eq 'local') {
			rename ($oldName, $newName);
		} else {
			$self->rename($oldName, $newName);
		}
	};
	# Here goes the rotation code    
	my ($oldName, $newName);
	if ( $i == 0 && &$exist($file) ) {
		$oldName = $file;
	} elsif ( &$exist("$file.$i") ) {
		$oldName = "$file.$i";
	}
	if ($oldName) {
		$newName = "$file." . ++$i;
		$self->_rotate_file($where, $file, $nversions, $i) unless ($i == $nversions);
		&$del($newName) if &$exist ($newName);
		&$move($oldName, $newName);
	}
}
sub DESTROY {
    my $self = shift;
    $self->close();
} 
1;
__END__
# Below is stub documentation for your module. You'd better edit it!