indexer/com.midnight.kuira.core.indexer.sync/SyncStateManager

SyncStateManager

class SyncStateManager(context: Context)

Manages subscription sync state for resuming after app restarts.

Purpose:

Persist last processed transaction ID per address
Enable subscription resumption (don't replay all history on restart)
Track sync progress

Storage:

Uses DataStore (shared preferences alternative)
Key format: "last_tx_id_{address}"
Value: Last processed transaction ID (Int)

Resume Flow:

App starts
Get last processed ID: getLastProcessedTransactionId(address)
Subscribe from that ID: subscribeToUnshieldedTransactions(address, lastId)
Process updates
Save progress: saveLastProcessedTransactionId(address, newId)

Example:

// On app start
val lastId = syncStateManager.getLastProcessedTransactionId(address)
// lastId = 42 (from previous session)

// Subscribe from last ID (skip already processed txs)
indexerClient.subscribeToUnshieldedTransactions(address, fromTransactionId = lastId)
    .collect { update ->
        utxoManager.processUpdate(update)

        if (update is Progress) {
            syncStateManager.saveLastProcessedTransactionId(address, update.highestTransactionId)
        }
    }

Constructors

SyncStateManager

constructor(context: Context)

Types

Companion

object Companion

Functions

clearAllSyncState

suspend fun clearAllSyncState()

Clear all sync state (for all addresses).

clearSyncState

suspend fun clearSyncState(address: String)

Clear sync state for an address.

getLastProcessedTransactionId

suspend fun getLastProcessedTransactionId(address: String): Int?

Get last processed transaction ID for an address.

getPinnedChainCheckpoint

suspend fun getPinnedChainCheckpoint(address: String): ChainCheckpoint?

The CHECKPOINT block the persisted caches were built against — a per-chain-instance identity for detecting a chain RESET. It is a block ABOVE genesis (height + hash): a localnet booting from a fixed chain spec reproduces the same GENESIS hash across a reset, so genesis can't be the discriminator, but any higher block carries a per-instance timestamp and so a per-instance hash. com.midnight.kuira.core.indexer.sync.ChainResetGuard re-looks-up this height on each sync; a missing block (shorter fresh chain) or a changed hash means a reset.

observeLastProcessedTransactionId

fun observeLastProcessedTransactionId(address: String): Flow<Int?>

Observe last processed transaction ID for an address.

saveLastProcessedTransactionId

suspend fun saveLastProcessedTransactionId(address: String, transactionId: Int)

Save last processed transaction ID for an address.

setPinnedChainCheckpoint

suspend fun setPinnedChainCheckpoint(address: String, checkpoint: ChainCheckpoint)

Pin checkpoint as the chain-instance identity the caches for address were built against.