core/rawdb: separate raw database access to own package (#16666)

core/rawdb/interfaces.go

@@ -0,0 +1,33 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package rawdb
+
+// DatabaseReader wraps the Has and Get method of a backing data store.
+type DatabaseReader interface {
+	Has(key []byte) (bool, error)
+	Get(key []byte) ([]byte, error)
+}
+
+// DatabaseWriter wraps the Put method of a backing data store.
+type DatabaseWriter interface {
+	Put(key []byte, value []byte) error
+}
+
+// DatabaseDeleter wraps the Delete method of a backing data store.
+type DatabaseDeleter interface {
+	Delete(key []byte) error
+}