Reset cache if version becomes active

[Leo-Besancon]

• document all added functions
• try in sandbox /simulation/labnet
  • if part of node-launch, checked using the resync_check flag
• unit tests on the added/changed features
  • make tests compile
  • make tests pass
• add logs allowing easy debugging in case the changes caused problems
• if the API has changed, update the API specification

[modship]

why it is now Option ?

[Leo-Besancon]

In order to destroy the DB to reset it, I needed a way to drop the current DB, which is not possible without the Option as I can't fully drop the HDCache.
The only alternative I thought was to iterate through the DB to remove elements, but this may be a heavy operation.

[damip]

the only other solution I see (without using Option) is

        unsafe {
            std::ptr::drop_in_place(&mut self.db);
            std::ptr::write(&mut self.db, create_new_db());
        }

but not great because unsafe

[sydhds]

Maye we can use the unsafe snippet here but check with Miri first if the code looks ok and sound?
If you want I can have a look at it?

[sydhds]

Maye we can use the unsafe snippet here but check with Miri first if the code looks ok and sound?
If you want I can have a look at it?