Allow custom SqlDriver to support multi-platform encryption

[izakvdhoven]

Use case

I need to be able to encrypt the normalised cache on non-Android targets (specifically iOS).

SqlDelight supports configuring a SqlDriver for encryption:

val configuration = DatabaseConfiguration(
    encryptionConfig = DatabaseConfiguration.Encryption("MyCacheEncryptionKey"),
    ...
)

val driver: SqlDriver = NativeSqliteDriver(configuration)

Describe the solution you'd like

I would like for the SqlNormalizedCacheFactory constructor to be made public, to allow supplying a customised SqlDriver when instantiating SqlNormalizedCacheFactory.

I understand that the constructor is internal to allow SqlDelight to remain an implementation detail, but this hides functionality already supported by the dependency.

Perhaps an overloaded constructor that allows passing an api-agnostic encryption config (eg, SqlNormalisedCacheEncryptionConfig) would solve the problem without leaking the SqlDelight dependency?

[martinbonnin]

It might be ok to expose SQLDelight transitively. After all, we're doing it for Okio and OkHttp already so it would be somewhat consistent.

The only thing that makes this code complicated is the expect/actual declaration. It's currently possible to create a SQLiteNormalizedCache from commonMain code by passing a name but in your case, I guess the code that creates the drivers is platform specific anyway so there's no need for a expect constructor(driver: SqlDriver), right?

[izakvdhoven]

the code that creates the drivers is platform specific anyway so there's no need for a expect constructor(driver: SqlDriver), right?

Correct.

SqlNormalizedCacheFactory already has a default constructor (not expect-actual) defined in androidMain, appleMain and jvmMain

actual class SqlNormalizedCacheFactory internal constructor(
    private val driver: SqlDriver,
) : NormalizedCacheFactory() {

Simply making this default constructor public should solve my problem without incurring additional overhead elsewhere.

[martinbonnin]

Want to open a PR about this? (you'll most likely have to run ./gradlew apiDump to update the public API).

[izakvdhoven]

Happy to take a stab at it.

Thanks!

[martinbonnin]

Fixed with #4806