Here's a file. Go ahead, use stat(), and try to calculate the size of the
message with an extra CR tacked on at the end of each line.
Once this information is calculated, is it cached anywhere so that the
next mailbox access can use it without re-reading the file?
It's not and this is certainly a valid suggestion.
If it's re-reading each message, it would seem a dramatic speed
improvement could be obtained by caching the size for later use, perhaps
by renaming the file, while still remaining RFC 1939-compliant. I know
that Maildir++ stores the size of the message in the name as
"xxxx,S=nnnnn", but it unfortunately stores the size as reported by
stat(), and not the CRLF octet size.
I still believe people should simply not create 100MB POP3 mailboxes. POP3
is simply the wrong tool for handling so much mail.