Let the thread load new messages. This may happen when user switches
the setting to delete messages on the server on and there are a lot of
messages to delete.
This prevents generation of a large number of jobs when IMAP deletion
setting is enabled for the first time. Writing jobs to the database
locks it for readers and may cause UI freezing, because chatlist and
messages can't be read until all jobs are written.
Note that on failure job will be written to the database, to make sure
it is postponed instead of being retried immediately.
Job::new() can be used to create jobs in-memory
Job.update() is replaced with Job.save() which can create new database
entries and consumes Job to avoid the need to update job ID after saving
it to the database.
This moves the loading of the keys from the database to the trait and
thus with types differing between public and secret keys. This
fetches the Config::ConfiguredAddr (configured_addr) directly from the
database in the SQL to simplify the API and consistency instead of
making this the responsiblity of all callers to get this right.
Since anyone invoking these methods also wants to be sure the keys
exist, move key generation here as well. This already simplifies some
code in contact.rs and will eventually replace all manual checks for
existing keys.
To make errors more manageable this gives EmailAddress it's own error
type and adds some conversions for it. Otherwise the general error
type leaks to far. The EmailAddress type also gets its ToSql trait impl
to be able to save it to the database directly.
If precheck_imf fails to check if message with the same rfc724_mid
already exists, the same message may be downloaded twice. Instead,
abort the whole operation and retry later.
For hidden messages, blobs are not deleted during housekeeping. To
actually free the space used by media files, messages should be moved to
trash instead of being hidden.
Some mobile email clients, such as apple mail, attach or inline images
after description, just like Delta Chat. It is better to display them
instead of ignoring.
