Before we yield a block for scanning, we save all of the contained script
public keys. Then, when we want the address credited for creating an output,
we read the script public key of the spent output from the database.
Fixes#559.
I don't love this. I wanted to simply add this function to `processor/key-gen`,
but then anyone who wants a view key needs to pull in Bulletproofs which is a
mess of code. They'd also be subject to an AGPL licensed library.
This is so small it should be a primitive elsewhere, yet there is no primitives
library eligible. Maybe serai-client since that has the code to make
transactions to Serai (and will have this as a dependency)? Except then the
processor has to import serai-client when this rewrite removed it as a
dependency.
We'd report the amount originally received, minus 2x the cost to aggregate,
regardless the amount successfully forwarded. We should've reduced to the
amount successfully forwarded, if it was smaller, in case the cost to
forward exceeded the aggregation cost.
The main benefit is whatever scheduler is in use, we now have a single API to
receive TXs to sign (which is of value to the TX signer crate we'll inevitably
build).
`acknowledge_batch` can only be run if we know what the Batch should be. If we
don't know what the Batch should be, we have to block until we do.
Specifically, we need the block number associated with the Batch.
Instead of blocking over the Scanner API, the Scanner API now solely queues
actions. A new task intakes those actions once we can. This ensures we can
intake the entire Substrate chain, even if our daemon for the external network
is stalled at its genesis block.
All of this for the block number alone seems ridiculous. To go from the block
hash in the Batch to the block number without this task, we'd at least need the
index task to be up to date (still requiring blocking or an API returning
ephemeral errors).
