Some background: I'm writing a DBI driver (pure perl) for a proprietary system. The transport layer to the "database" is over http, and there is a whole perl object framework for interacting with the database. I've got it working pretty nicely, but I need to implement an "interrupt" functionality that communicates back to the server in the case where the client is terminated either by a SIGTERM, SIGINT or by an alarm/timeout.

The framework supports this interrupt functionality, but it must know what request it needs to interrupt, meaning that the $SIG{INT}/$SIG{TERM} subroutine needs to know which DBI statement handle is active at the time, and act accordingly.

My initial thought was to do something like this: 

# This is $sth->execute
sub execute {
    my $sth = shift;
    ....
    my $req = BigHairyDatabaseInteraction->new(...);
    local $SIG{INT} = sub { $req->handleInterrupt };
 
    $req->execute;
    # When $req->excute comes back the entire query
    # has been processed, and all the rows are in $req.
    ...
}

[download]
Initial testing appear to show that this works, but I'm worried that by using a closure like this $req will never get destroyed due to dangling references. I haven't really used closures before, so my experience in that area is rather limited.

Does the above technique seem reasonable, or would you suggest other techniques to achieve the same result?

Thanks!

Michael

In reply to Closures, object destruction and memory leaks by mpeppler

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