The QNAM may continue to outlive both.
Rename Credentials::getQNAM() to createQNAM() while we're at it - it's
used to make a new QNAM that will subsequently be owned by the Account
object.
See d01065b9a1 for rationale.
Relates to
d40c56eda5147cf798a6
This moves the responsibility of asking the user or not for
credentials from the Credentials classes back to the AccountState.
fetch() now only extract credentials from the keychain, reports
the result to the AccountState which then decides if askFromUser()
should be called or not. The result is once more reported to the
AccounState.
This also replaces the HttpCredentials::queryPassword virtual
which now lets HttpCredentialsGui and HttpCredentialsText do it
the way that they prefer.
The original problem is that showing a popup not originated
from the main settings window while it's focused won't be
shown in front to the user.
This try not to highjack the user's attention of the user
by showing a notification when checking the connection for
valid credentials, and require the user to sign in through
the UI. There are still issues with showing that popup from
the tray icon, but the user will most likely be looking for
the popup in that case. The new sign in button directly in
the settings account works properly.
* Use a shared pointer to Account everywhere to ensure
the instance stays alive long enough for a sync to terminate
* Folder is now tied to an AccountState
* SyncEngine and OwncloudPropagator tie to an Account and use that
for all jobs they run
Issue: Since the setup wizard currently always replaces the
account, it will always wipe all folder definitions, even when
the actual changes to the account were minor.
