98 lines
2.3 KiB
Go
98 lines
2.3 KiB
Go
/*
|
|
*
|
|
* 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)
|
|
}
|