node: customizable protocol and service stacks

node/utils.go

@@ -0,0 +1,33 @@
+// Copyright 2015 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 node
+
+import (
+	"path/filepath"
+
+	"github.com/ethereum/go-ethereum/ethdb"
+)
+
+// openDatabase opens an existing database with the given name from within the
+// specified data directory, creating one if none exists. If the data directory
+// is empty, an ephemeral memory database is returned.
+func openDatabase(dataDir string, name string, cache int) (ethdb.Database, error) {
+	if dataDir == "" {
+		return ethdb.NewMemDatabase()
+	}
+	return ethdb.NewLDBDatabase(filepath.Join(dataDir, name), cache)
+}