middleware/client: make client middleware use StringStore and remove ClientStore

Fixes #158

server/store/memory/client_store.go

@@ -1,60 +0,0 @@
-// Copyright 2016 The Chihaya Authors. All rights reserved.
-// Use of this source code is governed by the BSD 2-Clause license,
-// which can be found in the LICENSE file.
-
-package memory
-
-import (
-	"sync"
-
-	"github.com/chihaya/chihaya"
-	"github.com/chihaya/chihaya/pkg/clientid"
-	"github.com/chihaya/chihaya/server/store"
-)
-
-func init() {
-	store.RegisterClientStoreDriver("memory", &clientStoreDriver{})
-}
-
-type clientStoreDriver struct{}
-
-func (d *clientStoreDriver) New(_ *store.DriverConfig) (store.ClientStore, error) {
-	return &clientStore{
-		clientIDs: make(map[string]struct{}),
-	}, nil
-}
-
-type clientStore struct {
-	clientIDs map[string]struct{}
-	sync.RWMutex
-}
-
-var _ store.ClientStore = &clientStore{}
-
-func (s *clientStore) CreateClient(clientID string) error {
-	s.Lock()
-	defer s.Unlock()
-
-	s.clientIDs[clientID] = struct{}{}
-
-	return nil
-}
-
-func (s *clientStore) FindClient(peerID chihaya.PeerID) (bool, error) {
-	clientID := clientid.New(string(peerID))
-	s.RLock()
-	defer s.RUnlock()
-
-	_, ok := s.clientIDs[clientID]
-
-	return ok, nil
-}
-
-func (s *clientStore) DeleteClient(clientID string) error {
-	s.Lock()
-	defer s.Unlock()
-
-	delete(s.clientIDs, clientID)
-
-	return nil
-}