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.
In preparation for out-of-order range-based scanning, it is necessary
to ensure that the size of the Sapling note commitment tree is carried
along through the scan process and that stored blocks are always
persisted with the updated note commitment tree size.
Local chain validation will be performed internal to
`scan_cached_blocks`, and as handling of chain reorgs will need to
change to support out-of-order scanning, the `validate_chain` method
will be superfluous. It is removed in advance of other changes in order
to avoid updating it to reflect the forthcoming changes.
We move thes fields out into a separate BlockMetadata struct to ensure
that future additions to block metadata are structurally separated from
future additions to block data.
`rusqlite` includes a mechanism for creating prepared statements that
automatically caches them and reuses the caches when possible. This
means that it's unnecessary for us to do our own caching, and also
offers a minor performance improvement in that we don't need to eagerly
prepare statements that we may not execute in the lifetime of a given
`WalletDb` object. It also improves code locality, because the prepared
statements are now adjacent in the code to the parameter assignment
blocks that correspond to those statements.
This also updates a number of `put_x` methods to use sqlite upsert
functionality via the `ON CONFLICT` clause, instead of having to perform
separate inserts and updates.
Memos may be absent for both sent and received notes in cases where only
compact block information has been used to populate the wallet database.
This fixes a potential crash in the case that we attempt to decode a
SQLite `NULL` as a byte array.
Fixes#384
(cherry picked from commit d99b4d4d6e)
Memos may be absent for both sent and received notes in cases where only
compact block information has been used to populate the wallet database.
This fixes a potential crash in the case that we attempt to decode a
SQLite `NULL` as a byte array. It does, however, introduce a slight
semantic confusion that will need to be considered in the case of future
updates where a note may not have an associated memo; at present, the
only reason we might not have the memo is that we might not have
retrieved the full transaction information from the chain, but in the
future there might be other possible reasons for this absence.
Fixes#384
This removes the `CommitmentTree`, `IncrementalWitness`, and
`MerklePath` types in favor of equivalent versions available
from the `incrementalmerkletree` crate.
This is in preparation for extraction into the `incrementalmerkletree`
crate, which is not Sapling-specific and therefore cannot hard-code
the depths of these data structures.
This better reflects the semantics of wallet behavior. Also, this
adds a `zcash_client_backend::WalletRead::get_min_unspent_height`
method that replaces the deprecated & removed (and misleadingly
named) `get_rewind_height` method.
This change also settles on `account_value_delta` as the name of the
column in `v_transactions` that describes the transaction's effect on
the value of the associated account.
This removes the path-based dependencies on the `zcash_note_encryption`
crate in favor of using versioned dependencies locally. This better
reflects the future state in which `zcash_note_encryption` is factored
out of the workspace and maintained in a separate repository.
The `halo2_proofs/multicore` flag must be disabled when running wasm
builds; this ensures that we do not accidentally include it as a
transitive dependency when building with `--no-default-features`.
Jack Grigg
Kris Nuttycombe
Kris Nuttycombe
Nate Wilcox
Daira Emma Hopwood
Hazel OHearn