[NOD-1507] Implement model.DBTransaction (#997)

domain/consensus/database/dbmanager.go

@@ -27,7 +27,11 @@ func (dbw *dbManager) Cursor(bucket model.DBBucket) (model.DBCursor, error) {
 }
 
 func (dbw *dbManager) Begin() (model.DBTransaction, error) {
-	panic("unimplemented")
+	transaction, err := dbw.db.Begin()
+	if err != nil {
+		return nil, err
+	}
+	return newDBTransaction(transaction), nil
 }
 
 // New returns wraps the given database as an instance of model.DBManager

domain/consensus/database/transaction.go

@@ -0,0 +1,34 @@
+package database
+
+import (
+	"github.com/kaspanet/kaspad/domain/consensus/model"
+	"github.com/kaspanet/kaspad/infrastructure/db/database"
+)
+
+type dbTransaction struct {
+	transaction database.Transaction
+}
+
+func (d dbTransaction) Put(key model.DBKey, value []byte) error {
+	return d.transaction.Put(dbKeyToDatabaseKey(key), value)
+}
+
+func (d dbTransaction) Delete(key model.DBKey) error {
+	return d.transaction.Delete(dbKeyToDatabaseKey(key))
+}
+
+func (d dbTransaction) Rollback() error {
+	return d.transaction.Rollback()
+}
+
+func (d dbTransaction) Commit() error {
+	return d.Commit()
+}
+
+func (d dbTransaction) RollbackUnlessClosed() error {
+	return d.RollbackUnlessClosed()
+}
+
+func newDBTransaction(transaction database.Transaction) model.DBTransaction {
+	return &dbTransaction{transaction: transaction}
+}