This commit was previously split into the following parts to ease
review:
- 2d746f68: replace imports
- 4008f0fd: use ecdsa.Signature
- 849e33d1: remove btcec.S256()
- b8f6ebbd: use v2 library correctly
- fa80bca9: bump go modules
With go 1.17 a change to the build flags was implemented:
https://go.googlesource.com/proposal/+/master/design/draft-gobuild.md
The formatter now automatically adds the forward-compatible build tag
format and the linter checks for them, so we need to include them in our
code.
Depends on btcsuite/btcwallet#757.
Pulls in the updated version of btcwallet and walletdb that have the DB
interface enhanced by their own View() and Update() methods with the
reset callback/closure supported out of the box. That way the global
package-level View() and Update() functions now become pure redirects.
We would establish the connection to the chain backend and start getting
block notifications before we had started the concurrent queues, which
would lead to the OnBlockConnected call being blocked, and a deadlock
(since GetBestBlock would never return).
Instead we make sure to start the queues before establishing the
connection, consuming the notifications right away.
In this commit, we extend the BtcdNotifier to support registering
scripts for spends notifications. Once the script has been detected as
spent within the chain, a spend notification will be dispatched through
the Spend channel of the SpendEvent returned upon registration.
For scripts that have been spent in the past, the rescan logic has been
modified to match on the script rather than the outpoint. This is done
by encoding the script as an address.
For scripts that are unspent, a request to the backend will be sent to
alert the BtcdNotifier of when the script was spent by a transaction. To
make this request we encode the script as an address, as this is what
the backend uses to detect the spend. The transaction will then be
proxied through the txUpdates concurrent queue, which will hand it off
to the underlying txNotifier and dispatch spend notifications to the
relevant clients.
Along the way, we also address an issue where we'd miss detecting that
an outpoint/script has been spent in the future due to not receiving a
historical dispatch request from the underlying txNotifier. To fix this,
we ensure that we always request the backend to notify us of the spend
once it detects it at tip, regardless of whether a historical rescan was
detected or not.
In this commit, we extend the BtcdNotifier to support registering
scripts for confirmation notifications. Once the script has been
detected as confirmed within the chain, a confirmation notification will
be dispatched to through the Confirmed channel of the ConfirmationEvent
returned upon registration.
For scripts that have confirmed in the past, the `historicalConfDetails`
method has been modified to skip the txindex and go straight to scanning
the chain manually if confirmation request is for a script. When
scanning the chain, we'll determine whether the script has been
confirmed by locating the script in an output of a confirmed
transaction.
For scripts that have yet to confirm, they will be properly tracked
within the TxNotifier.
In this commit, we add the current chain parameters to the BtcdNotifier.
This will be used in a future commit in order to convert outputs scripts
into addresses. This is needed since the btcd backend uses these
addresses to detect whether the script encoded within it was spent by a
transaction in the chain.
In this commit, we modify all existing historical rescans for
ChainNotifier backends to scan backwards rather than forwards. If we
know that a transaction has been confirmed, or outpoint spent, the it's
likely that the event has recently transpired assuming we've been
offline for a short period of time. Therefore, if we scan backwards
rather than forwards, then we can save potentially hundreds or thousands
of block fetches if the event recently happened close to the tip of the
chain.
We bound this search at the genesis block, to ensure we don't underflow
the uint32 used throughout the package in the main loop.
In this commit, we alter the different ChainNotifier implementations to
dispatch confirmation and spend notifications after blocks. We do this
to ensure the external consistency of our registered clients.
In this commit, we modify the logic within RegisterSpendNtfn for the
BtcdNotifier to account for the recent changes made to the TxNotifier.
Since it is now able to handle spend notification registration and
dispatch, we can bypass all the current logic within the
BtcdNotifier and interact directly with the TxNotifier instead.
The most notable change is that now we'll only attempt a historical
rescan if the TxNotifier tells us so.
In this commit, we address a bug where it's possible that we still
attempt to manually scan for a transaction to determine whether it's
been included in the chain even after successfully checking the txindex
and not finding it there. Now, we'll short-circuit this process by
exiting early if the txindex lookup was successful but the transaction
in question was not found. Otherwise, we'll fall back to the manual
scan.
