up to now, Chat-Group-Member-Added and -Removed commands
result in a complete recreation of the memberlist
by collecting all addresses from the From: and To: headers.
this easily results in missed and accidentally removed members,
esp. when several people at the same time scan a qr code to join a group.
this commit changes the behavior of adding members by
not removing members on the Chat-Group-Member-Added command.
instead the existing memberlist is conjuncted
with the memberlist seen in the message.
only adding the member from the Chat-Group-Member-Added
seems not to be sufficient - imaging a group of Alice and Bob:
- Alice adds Claire
- Bob adds Dave _before_ seeing that Alice added Claire
- Dave would never get the information that Claire is in the group
wrt Chat-Group-Member-Removed: this command
does no longer recreate the memberlist but just remove _exactly_ the member
mentioned in the header. there are situations, where a just removed member
will be readded by out-of-order-messages, however, compared to missed
members, this is seems to be acceptable - also as this is more visible
and easier to fix (just remove the member again).
might be that, in practise, this is not a big issue. while adding members
is typically done in masses on bootstraping a group,
this is typically not true for removing members.
This return value was very complicated to understand. Some failure
returns were returned as Err and some as Ok with no consistency, but
resulting in the same behaviour.
This refactor makes the handle_securejoin_handshake the sole place
responsible for maintaining the state of the secure join
process (context.bob) and also in charge of terminating the ongoing
process. This is none of receive_imf's business.
The remaining returns are now cleanly classified in application-errors
and protocol errors:
Applications errors result in an Err and mean there is a bug or
something else serious went wrong, like database access suddenly
failed or so. In this case receive_imf is still responsible for
clearing the state and resetting ongoing-process. It may be possible
this should still be moved back to securejoin.rs so that recieve_imf
doesn't need to know anything about this either.
Protocol errors are not failures for receive_imf, it just means the
received message didn't follow the protocol. Receive_imf in this case
is told to ignore the message: that is hide it but not delete it.
Other Ok returns also only say what needs to happen to the message:
- It's fully processed and needs no further processing, instead should
be removed
- It should still be processed as a normal received message.
This changes some behaviour: if the chat creation/lookup for the
contact fails this is treated as an application error. Previously
this was silently ignored and send_msg() would be called with a 0
chat_id without checking the response. This resulted in the protocol
quitely being blocked.
This all shhould now make it easier to resultify more of the functions
called by this function, instead of having to deal with very
complicated application logic hidden in the return code.
The struct really represents a parsed MIME message and is not used as
a parser itself. After the from_bytes() call (which should arguably
use the FromStr trait instead) the struct is fully populated.
we change the name on the wire as the old Chat-Group-Image header
could not be used on random mails, it was the marker for a "Changed" message,
if we would keep this names, things will fail for exising installations
as messages are dropped and a "Group image changed" message is shown instead.
