start refactoring

utils/shutdown/shutdown.go

@@ -0,0 +1,62 @@
+// Copyright 2017 fatedier, fatedier@gmail.com
+//
+// 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 shutdown
+
+import (
+	"sync"
+)
+
+type Shutdown struct {
+	doing  bool
+	ending bool
+	start  chan struct{}
+	down   chan struct{}
+	mu     sync.Mutex
+}
+
+func New() *Shutdown {
+	return &Shutdown{
+		doing:  false,
+		ending: false,
+		start:  make(chan struct{}),
+		down:   make(chan struct{}),
+	}
+}
+
+func (s *Shutdown) Start() {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if !s.doing {
+		s.doing = true
+		close(s.start)
+	}
+}
+
+func (s *Shutdown) WaitStart() {
+	<-s.start
+}
+
+func (s *Shutdown) Done() {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if !s.ending {
+		s.ending = true
+		close(s.down)
+	}
+}
+
+func (s *Shutdown) WaitDown() {
+	<-s.down
+}