Fantom-foundation/go-lachesis

package gossip

import (
    "github.com/ethereum/go-ethereum/ethdb"

    "github.com/Fantom-foundation/go-lachesis/utils/migration"
)

func isEmptyDB(db ethdb.Iteratee) bool {
    it := db.NewIterator(nil, nil)
    defer it.Release()
    return !it.Next()
}

func (s *Store) Migrate() error {
    versions := migration.NewKvdbIDStore(s.table.Version)
    if isEmptyDB(s.mainDb) && isEmptyDB(s.async.mainDb) {
        // short circuit if empty DB
        versions.SetID(s.migrations().ID())
        return nil
    }
    return s.migrations().Exec(versions)
}

func (s *Store) migrations() *migration.Migration {
    return migration.
        Begin("lachesis-gossip-store").
        Next("remove async data from sync DBs",
            func() error {
                s.rmPrefix(s.table.PackInfos, "serverPool")
                s.rmPrefix(s.mainDb, "Z")
                return nil
            }).
        Next("remove legacy genesis field",
            s.app.MigrateEraseGenesisField).
        Next("multi-delegations",
            s.app.MigrateMultiDelegations).
        Next("adjustable offline pruning time",
            s.app.MigrateAdjustableOfflinePeriod).
        Next("adjustable minimum gas price",
            s.app.MigrateAdjustableMinGasPrice)
}