In the process of making the internals of `scan_block_with_runner`
reusable across Sapling and Orchard, it became evident that key
identifier abstraction along the lines of #1175 is needed more
generally. This commit refactors the use of ZIP 32 account identifiers
and key scopes to better separate scanning concerns from ZIP 32 key
derivation. In the process, this removes a fair amount of unnecessary
polymorphism from `zcash_client_backend::wallet::WalletTx` and related
types.
This PR was extracted from https://github.com/zcash/librustzcash/pull/1175
in order to make the changes to `zcash_client_backend` usable without
the additional generalizations to `zcash_client_sqlite` made by that PR.
Co-authored-by: Andrew Arnott <andrewarnott@live.com>
In the event that the pool to which change should be sent cannot
automatically be determined based upon the inputs and outputs of a
transaction, it is up to the caller to specify where change should
be sent.
It needn't return the account id that was given as an input, and it shouldn't return an 11-byte diversifier index when a 31-bit child index is more appropriate.
This change makes it easier for third parties to make use of the Unified
key infrastructure without incurring a dependency upon the rest of the
`zcash_client_backend` interfaces.
This modifies the `compute_balance` method to operate in a
bundle-oriented fashion, which simplifies the API and makes it easier to
elide Orchard functionality in the case that the `orchard` feature is
not enabled.
This unification allows us to better isolate transparent-input dependent
functionality. Previously, `TransparentInputSource` could not be placed
under a feature flag because the interface was needed for proposal
deserialization; by instead making the transparent input source methods
flag-dependent, we can correctly produce an error when proposal
deserializaiton attempts to select transparent inputs and the feature
flag is off.
We plan to also introduce a similar flag to gate access to Sapling
functionality. Since introduction of Orchard functionality is still
nascent, it's the correct time to introduce this isolation, before
there's more functionality that needs to be isolated in this fashion.
`ReceivedNote` now allows Orchard notes to be represented as received
notes. As part of this change, received notes now track whether they
were received using internally- or externally-scoped viewing keys.
This eliminates the need to trial-regenerate notes using the wallet's
IVKs to determine scope at spend time.
Public methods for mutation of these fields have been provided that
perform checking for overflow of the valid monetary range as part
of their operation.
Kris Nuttycombe
Jack Grigg
Kris Nuttycombe
Andrew Arnott