improve IAM module

Signed-off-by: hongming <talonwan@yunify.com>

vendor/sigs.k8s.io/structured-merge-diff/fieldpath/pathelementmap.go

@@ -0,0 +1,85 @@
+/*
+Copyright 2018 The Kubernetes 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 fieldpath
+
+import (
+	"sort"
+
+	"sigs.k8s.io/structured-merge-diff/value"
+)
+
+// PathElementValueMap is a map from PathElement to value.Value.
+//
+// TODO(apelisse): We have multiple very similar implementation of this
+// for PathElementSet and SetNodeMap, so we could probably share the
+// code.
+type PathElementValueMap struct {
+	members sortedPathElementValues
+}
+
+func MakePathElementValueMap(size int) PathElementValueMap {
+	return PathElementValueMap{
+		members: make(sortedPathElementValues, 0, size),
+	}
+}
+
+type pathElementValue struct {
+	PathElement PathElement
+	Value       value.Value
+}
+
+type sortedPathElementValues []pathElementValue
+
+// Implement the sort interface; this would permit bulk creation, which would
+// be faster than doing it one at a time via Insert.
+func (spev sortedPathElementValues) Len() int { return len(spev) }
+func (spev sortedPathElementValues) Less(i, j int) bool {
+	return spev[i].PathElement.Less(spev[j].PathElement)
+}
+func (spev sortedPathElementValues) Swap(i, j int) { spev[i], spev[j] = spev[j], spev[i] }
+
+// Insert adds the pathelement and associated value in the map.
+func (s *PathElementValueMap) Insert(pe PathElement, v value.Value) {
+	loc := sort.Search(len(s.members), func(i int) bool {
+		return !s.members[i].PathElement.Less(pe)
+	})
+	if loc == len(s.members) {
+		s.members = append(s.members, pathElementValue{pe, v})
+		return
+	}
+	if s.members[loc].PathElement.Equals(pe) {
+		return
+	}
+	s.members = append(s.members, pathElementValue{})
+	copy(s.members[loc+1:], s.members[loc:])
+	s.members[loc] = pathElementValue{pe, v}
+}
+
+// Get retrieves the value associated with the given PathElement from the map.
+// (nil, false) is returned if there is no such PathElement.
+func (s *PathElementValueMap) Get(pe PathElement) (value.Value, bool) {
+	loc := sort.Search(len(s.members), func(i int) bool {
+		return !s.members[i].PathElement.Less(pe)
+	})
+	if loc == len(s.members) {
+		return value.Value{}, false
+	}
+	if s.members[loc].PathElement.Equals(pe) {
+		return s.members[loc].Value, true
+	}
+	return value.Value{}, false
+}