refact(csi): use common lib-csi imports (#263)

Signed-off-by: shubham <shubham.bajpai@mayadata.io>

vendor/github.com/openebs/lib-csi/pkg/common/helpers/helpers.go

@@ -0,0 +1,45 @@
+/*
+Copyright 2020 The OpenEBS 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 helpers
+
+import (
+	"strings"
+)
+
+// GetCaseInsensitiveMap coercs the map's keys to lower case, which only works
+// when unicode char is in ASCII subset. May overwrite key-value pairs on
+// different permutations of key case as in Key and key. DON'T force values to the
+// lower case unconditionally, because values for keys such as mountpoint or
+// keylocation are case-sensitive.
+// Note that although keys such as 'comPREssion' are accepted and processed,
+// even if they are technically invalid, updates to rectify such typing will be
+// prohibited as a forbidden update.
+func GetCaseInsensitiveMap(dict *map[string]string) map[string]string {
+	insensitiveDict := map[string]string{}
+
+	for k, v := range *dict {
+		insensitiveDict[strings.ToLower(k)] = v
+	}
+	return insensitiveDict
+}
+
+// GetInsensitiveParameter handles special case ofGetCaseInsensitiveMap looking up one
+// key-value pair only
+func GetInsensitiveParameter(dict *map[string]string, key string) string {
+	insensitiveDict := GetCaseInsensitiveMap(dict)
+	return insensitiveDict[strings.ToLower(key)]
+}