Prior to this change, it's necessary to implement the entirety of the
`WalletRead` trait in order to be able to use the input selection
functionality provided by `zcash_client_backend::data_api::input_selection`.
This change factors out the minimal operations required for transaction
proposal construction to better reflect the principle of least authority
and make the input selection code reusable in more contexts.
In order to minimize the operations of the newly-created `InputSource`
and `ShieldingSource` traits, this change also removes the
`min_confirmations` field from transaction proposals, in favor of
storing explicit target and anchor heights. This has the effect of
limiting the lifetime of transaction proposals to `PRUNING_DEPTH -
min_confirmations` blocks.
This fixes an API issue whereby it was possible to execute a `Proposal`
with a different value of `min_confirmations` than that with which the
`Proposal` was constructed.
`StandardFeeRule` is an enumeration of the standard fees that have
existed in the history of Zcash zips. It is provided to simplify
transition to new fee strategies; legacy elements of this enumeration
are introduced already-deprecated.
The existing API limited change outputs to having only a single memo
repeated across each change output. This change makes it so that each
proposed change output can have its own associated memo, and leaves it
up to the input selector to determine how requested change memos are
associated with change outputs.
In order to use `uint64` for amounts that must be nonnegative in the
`proposal.proto` file, it is useful to update fee and change computation
to use `NonNegativeAmount` where possible.
When scanning, a wallet only needs to update balance and transaction
information shown to users when the scan has resulted in a change to
wallet state. This modifies `scan_cached_blocks` to return the range of
block heights actually scanned, along with the counts of notes spent and
received by the wallet in that range.
Fixes#918
The intent of this API is to provide a single API which returns in a
single call:
* per-account balances, including pending values
* wallet sync progress
Fixes#865Fixes#900
This also removes the zcash_client_sqlite-specific database
initialization procedures in favor of a standardized approach using the
methods available via the data access API.
The `zcash_client_backend::proto::service::compact_tx_streamer_client`
is now the only module controlled by that feature flag, exposing the
service types for use by parsers.
Prior to the scan-before-sync changes, the wallet was able to assume
that the maximum scanned block height at the time of the spend was
within a few blocks of the chain tip. However, under linear scanning
after the spend-before-sync changes this invariant no longer holds,
resulting in a situation where in linear sync conditions the wallet
could attempt to create transactions with already-past expiry heights.
This change separates the notion of "chain tip" from "max scanned
height", relying upon the `scan_queue` table to maintain the wallet's
view of the consensus chain height and using information from the
`blocks` table only in situations where the latest and/or earliest
scanned height is required.
As part of this change, the `WalletRead` interface is also modified to
disambiguate these concepts.
Previously this was not clearly specified, and the implementations in
`zcash_client_sqlite` behaved similarly to when `from_height = None`.
Closeszcash/librustzcash#892.
In general, it is preferable to use globally relevant identifiers where
possible. This PR removes the `WalletRead::TxRef` associated type in
favor of using `TxId` directly for the transaction identifier, and
restricts the use of the `NoteRef` type to those scenarios where the
result of one query is intended to be used directly as the input to
another query.
Closes#834
This implements a priority queue backed by the wallet database for scan
range ordering. The scan queue is updated on each call to `put_blocks`
or to `update_chain_tip`.
Instead of calling `put_block` for each block scanned,
`scan_cached_blocks` will now defer the block writes until the scan of a
batch is complete and will perform the block writes and note commitment
tree updates all within a single transaction.
This should ordinarily be fine in terms of memory consumption, because
the block data being saved is pruned to only that spend an output
information that is related to transactions in the wallet, which will
normally be sparse enough that the block range size that is appropriate
for a given platform to run within a batch scanner adequately bounds the
memory consumption of this pruned representation.
There are cases where we wish to return informaiton that is relevant to
a specific shielded protocol and `Transparent` is an invalid case. This
is a minor preparatory refactoring that makes this distinction
expressible.
Kris Nuttycombe
Jack Grigg
Matthew Watt
sasha
Matthew Watt
Kris Nuttycombe