This commit revamps the previous WalletController interface, edging it
closer to a more complete version.
Additionally, this commit also introduces two new interfaces:
BlockchainIO, and Singer along with a new factor driver struct, the
WalletDriver.
This BlockChainIO abstracts read-only access to the blockchain, while
the Singer interface abstracts the signing of inputs from the base
wallet paving the way to hardware wallets, air-gapped signing, etc.
Finally, in order to provide an easy method for selecting a particular
concrete implementation of a WalletController interface, the concept of
registering “WalletDriver”s has been introduced. A wallet driver is
essentially the encapsulation of a factory function capable of create a
new instance of a Wallet Controller.
This commit refactors the code within lnwallet interacting with the
ChainNotifier to accept, and call against the implementation rather
than a single concrete implementation.
LightningWallet no longer creates it’s own BtcdNotifier implementation
doing construction, now instead accepting a pre-started `ChainNotifier`
interface. All imports have been updated to reflect the new naming
scheme.
This method has been added in order to allow lnd to collect eligible
unspent witness programs outputs from the wallet controller for use as
inputs to the funding transaction.
Additionally, the change address functions now also specify whether the
generated change address should be payable to a witness program or not.
The WalletController will serve as a layer of separation between “base”
Bitcoin wallet logic, and the higher level Lightning Network logic. As
a result LightningWallet will no behave as an overly wallet, relying on
the lower wallet for basic services such as new address, signing etc.
Within this higher level lies the awareness of channel types, chain
monitoring, HTLCs, and so on.
