This adds a fee calculation strategy abstraction that can be used to
dynamically compute fees so that the total fees required may be taken
taken into account during note selection, and also removes automatic
change creation from the transaction builder.
Change outputs must now be directly created by the caller by the caller.
This is a necessary prerequisite for permitting fees to adjust based
upon the contents of the transaction being constructed.
The initial implementation of the fee strategy simply uses the current
default fee.
Previously, `shield_transparent_funds` was only shielding funds
associated with the legacy default transparent address. This meant
that transparent funds sent to unified addresses could not reliably
be shielded, as a unified address will frequently be constructed
using a diversifier index greater than zero.
This modifies the `get_transparent_receivers` method to return address
metadata containing the account ID and diversifier index used to derive
each address along with the receiver.
In 47a0d0d2b7 `WalletWriteTransparent` was
merged into `WalletWrite`, including its associated type `UtxoRef`.
However, `shield_transparent_funds` placed a bound on this associated
type that was not moved to `WalletWrite`. This left the generic
parameter `U` unconstrained, which didn't cause a local failure because
the method has no local tests, but was immediately apparent when trying
to use the method in the mobile SDKs.
This modifies `decrypt_and_store_transaction` to check for inputs
to a transaction being decrypted that correspond to utxos known
to our wallet. For each such UTXO found, it is marked spent.
These traits introduce a problem, in that constraints on a method cannot
be conditionally required based upon the presence or absence of a
feature flag. Instead, we make the methods previously introduced by
the removed traits present in all cases on the `WalletRead` and
`WalletWrite` traits, but ensure that their implementations return
an error if the caller attempts to use them in a wallet that has not
been configured with support for transparent inputs functionality.
Due to how the wallets retrieved unspent transparent outputs from the
light wallet server, the account associated with a particular UTXO may
not be known by the light wallet. Instead of requiring the caller to
perform a separate lookup and match the address of the received UTXO
with a known account, it's simpler to perform this lookup internally at
the time of insertion or update.
In order to make this operation more efficient, the `addresses_table`
migration is modified to add a column to cache the transparent receiver
so that it may be used in the joins in the UTXO insert and update
operations.
The currently deprecated implementations of `insert_sent_utxo`,
`insert_sent_note`, `put_sent_utxo` and `put_sent_note` all store to the
same `sent_notes` table internally. Since there's no immediate plan to
change this arrangement, it's better to have a single pair of internal
`insert_sent_output` and `put_sent_output` methods instead.
As of zcash/librustzcash#633, `SaplingDomain::IncomingViewingKey` now
allocates memory internally, and this memory persists as long as the
`BatchRunner` is alive. Now that we have decoupled the measurement of
heap usage for batch tasks from their internals, we can add bounds to
all of the generic parameters of `Batch` to enable correctly measuring
their actual heap usage.
We also add `DynamicUsage` impls for a bunch of `zcash_primitives` types
that will be used with `BatchRunner` (or its equivalent implementation
in `zcashd`) by callers.
This enables the heap usage measurements to be conditionally enabled by
the `BatchRunner` user. Importantly, when heap usage measurements are
not enabled, the `DynamicUsage` bound on `Batch` is not required.
This refactor also fixes a bug in the prior implementation. We were
counting the heap usage of a task when it started to run, but the item
may have been in the `rayon` work-stealing queues for a non-negligible
period before then. We now count the heap usage immediately before
spawning the task into the `rayon` thread pool.
Previously we were sending an `Option<DecryptedNote>` from each `Batch`
back to its parent `BatchRunner`. However, this requires allocating
sufficient space in the channel to handle the case where every output
can be decrypted. In general this will not be the case, and we can
instead signal "nothing decrypted" by just dropping the channel sender.
This reduces the post-batch-scanning memory usage of `BatchRunner` from
being linear in the number of on-chain outputs, to being linear in the
number of outputs for the wallet.
Ported from zcash/zcash@f7f6c2070d.
str4d
Kris Nuttycombe
Sean Bowe
Kris Nuttycombe
Daira Hopwood