Mimeparser.was_encrypted() checks if the message is an Autocrypt encrypted
message. It already means the message has a valid signature.
This commit documents a few functions to make it clear that signatures
stored in Mimeparser must be valid and must always come from encrypted
messages.
Also one unwrap() is eliminated in encrypted_and_signed(). It is possible
to further simplify encrypted_and_signed() by skipping the was_encrypted()
check, because the function only returns true if there is a matching
signature, but it is helpful for debugging to distinguish between
non-Autocrypt messages and messages whose fingerprint does not match.
Add a mutex to prevent a race condition when a "your pw is wrong" warning is sent, resulting in multiple messeges being sent.
Do not mute the device chat but "only" send MsgsChanged event when no
notification shall be shown.
More logging.
Parallel processing of messages results in bugs such as messages sent by
a new member being processed before the message that adds this member to
the chat, even when it has lower UID. In this case, messages are shown as
"[Unknown sender for this chat. See 'info' for more details.]", while
there is a message "Member ... added" right before, because writing the
information about new member to the database takes longer then reading
old index from the database.
With this change, API user does not need to look at the timestamp of
the next message to display the day marker, but can get the timestamp
directly from the marker. This way there is no database query and no
risk of error as a result of database being busy or message being deleted.
instead of applying all config_defaults unconditionally
after the first configure, a config_defaults for a given key
is now applied when this key has never been set before.
this way, you can set some keys before calling configure()
and also, later versions can add new defaults for new keys
(that would require another call to configure() then, however)
