Mail::Milter::Wrapper - Perl extension for wrappering milter objects

       Todd Vierling, <tv@duh.org> <tv@pobox.com>

       Mail::Milter::Wrapper wraps another milter, allowing for interception of the passed arguments and/or
       return code of the contained milter.

       new(MILTER, CODEREF[, CALLBACK ...])
           Creates a Mail::Milter::Wrapper object.

           MILTER  is the milter to wrap, which may be a plain hash reference or an instance of a hashref object
           such as "Mail::Milter::Object".  CODEREF is the wrapper subroutine.   CALLBACKs,  if  specified,  are
           named callbacks which are needed by the wrapper, even if the contained milter does not use them.

           The wrapper subroutine will be called with the following arguments, in this order:

            * reference to the wrapper
            * name of callback
            * subroutine reference to call into the wrapped milter
            * arguments for the callback (>= 0)

           This  subroutine should ALWAYS pass the "close" callback through to the contained milter.  Failure to
           do so may corrupt the contained milter's state information and cause memory leaks.

           As an example, a simple subroutine which just passes the callback through might be written as:

               sub callback_wrapper {
                   shift; # don't need $this
                   my $cbname = shift;
                   my $callback_sub = shift;

                   &$callback_sub(@_);
               }

       Mail::Milter::Wrapper - Perl extension for wrappering milter objects

       Mail::Milter, Sendmail::Milter

perl v5.36.0                                       2023-01-22                         Mail::Milter::Wrapper(3pm)

           use Mail::Milter::Wrapper;

           my $milter = ...;
           my $wrapper = new Mail::Milter::Wrapper($milter, \&foo);

           use Sendmail::Milter;
           ...
           Sendmail::Milter::register('foo', $wrapper, SMFI_CURR_ACTS);