vendor files

vendor/k8s.io/kubernetes/pkg/util/keymutex/keymutex.go

@@ -0,0 +1,83 @@
+/*
+Copyright 2015 The Kubernetes 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 keymutex
+
+import (
+	"fmt"
+	"sync"
+
+	"github.com/golang/glog"
+)
+
+// KeyMutex is a thread-safe interface for acquiring locks on arbitrary strings.
+type KeyMutex interface {
+	// Acquires a lock associated with the specified ID, creates the lock if one doesn't already exist.
+	LockKey(id string)
+
+	// Releases the lock associated with the specified ID.
+	// Returns an error if the specified ID doesn't exist.
+	UnlockKey(id string) error
+}
+
+// Returns a new instance of a key mutex.
+func NewKeyMutex() KeyMutex {
+	return &keyMutex{
+		mutexMap: make(map[string]*sync.Mutex),
+	}
+}
+
+type keyMutex struct {
+	sync.RWMutex
+	mutexMap map[string]*sync.Mutex
+}
+
+// Acquires a lock associated with the specified ID (creates the lock if one doesn't already exist).
+func (km *keyMutex) LockKey(id string) {
+	glog.V(5).Infof("LockKey(...) called for id %q\r\n", id)
+	mutex := km.getOrCreateLock(id)
+	mutex.Lock()
+	glog.V(5).Infof("LockKey(...) for id %q completed.\r\n", id)
+}
+
+// Releases the lock associated with the specified ID.
+// Returns an error if the specified ID doesn't exist.
+func (km *keyMutex) UnlockKey(id string) error {
+	glog.V(5).Infof("UnlockKey(...) called for id %q\r\n", id)
+	km.RLock()
+	defer km.RUnlock()
+	mutex, exists := km.mutexMap[id]
+	if !exists {
+		return fmt.Errorf("id %q not found", id)
+	}
+	glog.V(5).Infof("UnlockKey(...) for id. Mutex found, trying to unlock it. %q\r\n", id)
+
+	mutex.Unlock()
+	glog.V(5).Infof("UnlockKey(...) for id %q completed.\r\n", id)
+	return nil
+}
+
+// Returns lock associated with the specified ID, or creates the lock if one doesn't already exist.
+func (km *keyMutex) getOrCreateLock(id string) *sync.Mutex {
+	km.Lock()
+	defer km.Unlock()
+
+	if _, exists := km.mutexMap[id]; !exists {
+		km.mutexMap[id] = &sync.Mutex{}
+	}
+
+	return km.mutexMap[id]
+}