XL: bring in new storage API. (#1780)

Fixes #1771

storage-interface.go

@@ -0,0 +1,34 @@
+/*
+ * Minio Cloud Storage, (C) 2016 Minio, Inc.
+ *
+ * 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 main
+
+// StorageAPI interface.
+type StorageAPI interface {
+	// Volume operations.
+	MakeVol(volume string) (err error)
+	ListVols() (vols []VolInfo, err error)
+	StatVol(volume string) (vol VolInfo, err error)
+	DeleteVol(volume string) (err error)
+
+	// File operations.
+	ListDir(volume, dirPath string) ([]string, error)
+	ReadFile(volume string, path string, offset int64, buf []byte) (n int64, err error)
+	AppendFile(volume string, path string, buf []byte) (n int64, err error)
+	RenameFile(srcVolume, srcPath, dstVolume, dstPath string) error
+	StatFile(volume string, path string) (file FileInfo, err error)
+	DeleteFile(volume string, path string) (err error)
+}