The Android and Rust code have previously managed joint custody of the derived data database. With more complex migrations now required, we need to make the Android side read-only. To achieve that, the Android side will remove Room and instead rely on more primitive SQLite APIs for read-only access.
As part of implementing this change, database management throughout the SDK is being refactored.
There will be multiple representations of the data:
- Database representation (and some Entity representations in the places that Room hasn’t been removed yet). These representations are not as type safe and don’t match Kotlin best practices in all cases.
- Once #615 is implemented there will also be network representations
- Type safe models, which often appear in the public API The Database and Network representations will be converted to and from the type safe model representation.
We need the transparent account privkey in order to be able to derive
the secret key for any leaf transparent address under the ZIP 316
diversified address tree.
UnifiedViewingKey had a bug that made it incompatible with ZIP 316.
For compatibility with the current `zcash/librustzcash` revision we use
a temporary fake UFVK encoding that stores sufficient information to use
the current APIs, and a superset of the actual ZIP 316 FVK information.
- Replace int with type safe BlockHeight(Long) object
- Fix down casting bug, as BlockHeight is uint32 but Java only supports int32 or int64
- Rename WalletBirthday to Checkpoint and hide from the public API
While there are a lot of changes, the most significant are:
- Update the main entrypoint of the SDK to use a suspending function and eliminate lazy initialization. This also resolves#310
- Changing Dao methods to `suspend`, allowing Room to implicitly manage the threading model under the hood
- Explicitly set the executor thread for the `CompactBlockDb` and `DerivedDataDb`, which is the same thread used when calling into the Rust native library. Room will then use this thread for `suspend` fun calls into it
- With the above set, remove unnecessary hops to Dispatchers.IO which is a thread pool
- Eliminate lazy initialization in `PagedTransactionRepository` to make it easier to reason about the threading model and resolve#355 where the database was being touched from the UI thread
Note that `PendingTransactionsDb` is not opted into this single-threaded approach, because that database is not shared with the Rust code
To quickly get this implemented, some calls in the demo-app have been wrapped in `runBlocking {}`. This is not ideal and will be addressed in followup issues.
Simplifies running the SDK test suite versus darkside tests (which require special environment setup).
Note that the darkside tests are still broken. This is not a regression, as they were broken before. This is an intermediate step towards fixing those tests.