minio/vendor/google.golang.org/grpc/stickiness_linkedmap.go
Nitish Tiwari 2aa18cafc6 Update federation target to etcd/clientv3 (#6119)
With CoreDNS now supporting etcdv3 as the DNS backend, we
can update our federation target to etcdv3. Users will now be
able to use etcdv3 server as the federation backbone.

Minio will update bucket data to etcdv3 and CoreDNS can pick
that data up and serve it as bucket style DNS path.
2018-07-12 14:12:40 -07:00

97 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)
}