Re: linear processing of MIME documents with content-disposition headers
Here's how I envision it working:
The mail reader reads each body part in order. "hidden" body parts
are not displayed, but are decoded and stored in files for later use.
When a later body part "requires" an earlier "hidden" body part,
the "hidden" body part is made available to the display module
for the body part that "requires" it (perhaps via an open file
descriptor, passing its filename in the environment, whatever.)
If the end of the mail message (or message/rfc822 body part) is
reached and no body part has "required" the "hidden" body part,
the mail reader will display the "hidden" body part separately
(or offer to do so).
I'm not sure what I would do with the "owner" bit.
This works as long as "hidden" body parts are required to preceed
the parts that reference them.
One problem with multipart/related is that there is no way to
have multiple "container" parts (say RTF and HTML) that each
reference several "hidden" parts. I would like to be able to
have multiple "container" parts under a multipart/alternative,
be able to reference "hidden" parts. This is because I don't
expect to see a standard "container" emerge anytime soon.