GRDB Support

[stevensJourney]

Overview

This builds off the amazing work of powersync-ja/powersync-kotlin#230. The linked PR adds support for creating a PowerSyncDatabase by supplying a custom SQLiteConnectionPool which manages SQLite connections.

Some small additions and wip tests were added to the Kotlin implementation here

This PR adds Swift bindings to the Kotlin PR and then adds a PowerSyncGRDB Product to our SPM package. This product adapts a GRDB DatabasePool to a SQLiteConnectionPool accepted by the PowerSync SDK.

This makes use of the fact that GRDB exposes the raw C SQLite pointer for it's connections. We then use this pointer with the newly introduced native Database kotlin implementation.

The PowerSyncGRDB product provides a means to generate a GRDB Configuration. This configuration is used when creating the GRDB DatabasePool. We supply implementation for the configuration to load our PowerSync Rust core extension.

APIs are still a WIP
Consumers can create a Pool with:

var config = Configuration()

try config.configurePowerSync(
    schema: schema
)

let documentsDir = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
let dbURL = documentsDir.appendingPathComponent("test.sqlite")
let pool = try DatabasePool(
    path: dbURL.path,
    configuration: config
)

Consumers can then pass this pool when creating the PowerSyncDatabase.

let powerSync = openPowerSyncWithGRDB(
    pool: grdb,
    schema: schema,
    identifier: "mydatabase.sqlite"
)

Using the DatabasePool in the PowerSync SDK results in the same locking mechanisms being used between instances of the PowerSyncDatabase and DatabasePool. Consumers should be safe to alternate between both clients.

try await powerSync.execute(
    "INSERT INTO users(id, name, count) VALUES(uuid(), 'steven', 1)"
)

let initialUsers = try await powerSync.getAll(
    "SELECT * FROM users"
) { cursor in
    try cursor.getString(name: "name")
}
print("initial users \(initialUsers)")

// Now use a GRDB query
struct Users: Codable, Identifiable, FetchableRecord, PersistableRecord {
    var id: String
    var name: String
    var count: Int

    enum Columns {
        static let name = Column(CodingKeys.name)
        static let count = Column(CodingKeys.count)
    }
}

let grdbUsers = try await pool.read { db in
    try Users.fetchAll(db)
}

Demo

A new GRDB demo application has been added to the demos folder. This demo uses GRDB queries in Views.

grdbdemo.mp4

TODOs:

• Implement LeaseAll to lease all GRDB connections if possible
  • Documented that updating the Schema, after init, is not currently supported
• Update notifications
• Test latest version of GRDB with support for SQLite view mutations

[simolus3]

This looks really nice, I'm very happy with the GRDB implementation. Glad that all the effort to move to CSQLite is finally paying off :D

I only have a few minor comments, the implementation overall looks good to me.