dir: add new blobserver/dir package to do localdisk or diskpacked

Change-Id: I27a2d6b7a00e34490b9da264280c5b10f81c30ec

pkg/blobserver/dir/dir.go

@@ -0,0 +1,42 @@
+/*
+Copyright 2014 The Camlistore Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package dir implements the blobserver Storage interface for a directory,
+// detecting whether the directory is file-per-blob (localdisk) or diskpacked.
+// If neither, it initializes diskpacked.
+package dir
+
+import (
+	"camlistore.org/pkg/blobserver"
+	"camlistore.org/pkg/blobserver/diskpacked"
+	"camlistore.org/pkg/blobserver/localdisk"
+)
+
+// New returns a new blobserver Storage implementation, storing blobs in the provided dir.
+// If dir has an index.kv file, a diskpacked implementation is returnd.
+func New(dir string) (blobserver.Storage, error) {
+	if v, err := diskpacked.IsDir(dir); err != nil {
+		return nil, err
+	} else if v {
+		return diskpacked.New(dir)
+	}
+	if v, err := localdisk.IsDir(dir); err != nil {
+		return nil, err
+	} else if v {
+		return localdisk.New(dir)
+	}
+	return diskpacked.New(dir)
+}