vendor update for CSI 0.3.0

vendor/google.golang.org/grpc/stickiness_linkedmap.go

@@ -0,0 +1,97 @@
+/*
+ *
+ * Copyright 2018 gRPC 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 grpc
+
+import (
+	"container/list"
+)
+
+type linkedMapKVPair struct {
+	key   string
+	value *stickyStoreEntry
+}
+
+// linkedMap is an implementation of a map that supports removing the oldest
+// entry.
+//
+// linkedMap is NOT thread safe.
+//
+// It's for use of stickiness only!
+type linkedMap struct {
+	m map[string]*list.Element
+	l *list.List // Head of the list is the oldest element.
+}
+
+// newLinkedMap returns a new LinkedMap.
+func newLinkedMap() *linkedMap {
+	return &linkedMap{
+		m: make(map[string]*list.Element),
+		l: list.New(),
+	}
+}
+
+// put adds entry (key, value) to the map. Existing key will be overridden.
+func (m *linkedMap) put(key string, value *stickyStoreEntry) {
+	if oldE, ok := m.m[key]; ok {
+		// Remove existing entry.
+		m.l.Remove(oldE)
+	}
+	e := m.l.PushBack(&linkedMapKVPair{key: key, value: value})
+	m.m[key] = e
+}
+
+// get returns the value of the given key.
+func (m *linkedMap) get(key string) (*stickyStoreEntry, bool) {
+	e, ok := m.m[key]
+	if !ok {
+		return nil, false
+	}
+	m.l.MoveToBack(e)
+	return e.Value.(*linkedMapKVPair).value, true
+}
+
+// remove removes key from the map, and returns the value. The map is not
+// modified if key is not in the map.
+func (m *linkedMap) remove(key string) (*stickyStoreEntry, bool) {
+	e, ok := m.m[key]
+	if !ok {
+		return nil, false
+	}
+	delete(m.m, key)
+	m.l.Remove(e)
+	return e.Value.(*linkedMapKVPair).value, true
+}
+
+// len returns the len of the map.
+func (m *linkedMap) len() int {
+	return len(m.m)
+}
+
+// clear removes all elements from the map.
+func (m *linkedMap) clear() {
+	m.m = make(map[string]*list.Element)
+	m.l = list.New()
+}
+
+// removeOldest removes the oldest key from the map.
+func (m *linkedMap) removeOldest() {
+	e := m.l.Front()
+	m.l.Remove(e)
+	delete(m.m, e.Value.(*linkedMapKVPair).key)
+}