vendor files

vendor/k8s.io/kubernetes/pkg/controller/lookup_cache.go

@@ -0,0 +1,92 @@
+/*
+Copyright 2016 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 controller
+
+import (
+	"hash/fnv"
+	"sync"
+
+	"github.com/golang/groupcache/lru"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	hashutil "k8s.io/kubernetes/pkg/util/hash"
+)
+
+type objectWithMeta interface {
+	metav1.Object
+}
+
+// keyFunc returns the key of an object, which is used to look up in the cache for it's matching object.
+// Since we match objects by namespace and Labels/Selector, so if two objects have the same namespace and labels,
+// they will have the same key.
+func keyFunc(obj objectWithMeta) uint64 {
+	hash := fnv.New32a()
+	hashutil.DeepHashObject(hash, &equivalenceLabelObj{
+		namespace: obj.GetNamespace(),
+		labels:    obj.GetLabels(),
+	})
+	return uint64(hash.Sum32())
+}
+
+type equivalenceLabelObj struct {
+	namespace string
+	labels    map[string]string
+}
+
+// MatchingCache save label and selector matching relationship
+type MatchingCache struct {
+	mutex sync.RWMutex
+	cache *lru.Cache
+}
+
+// NewMatchingCache return a NewMatchingCache, which save label and selector matching relationship.
+func NewMatchingCache(maxCacheEntries int) *MatchingCache {
+	return &MatchingCache{
+		cache: lru.New(maxCacheEntries),
+	}
+}
+
+// Add will add matching information to the cache.
+func (c *MatchingCache) Add(labelObj objectWithMeta, selectorObj objectWithMeta) {
+	key := keyFunc(labelObj)
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+	c.cache.Add(key, selectorObj)
+}
+
+// GetMatchingObject lookup the matching object for a given object.
+// Note: the cache information may be invalid since the controller may be deleted or updated,
+// we need check in the external request to ensure the cache data is not dirty.
+func (c *MatchingCache) GetMatchingObject(labelObj objectWithMeta) (controller interface{}, exists bool) {
+	key := keyFunc(labelObj)
+	// NOTE: we use Lock() instead of RLock() here because lru's Get() method also modifies state(
+	// it need update the least recently usage information). So we can not call it concurrently.
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+	return c.cache.Get(key)
+}
+
+// Update update the cached matching information.
+func (c *MatchingCache) Update(labelObj objectWithMeta, selectorObj objectWithMeta) {
+	c.Add(labelObj, selectorObj)
+}
+
+// InvalidateAll invalidate the whole cache.
+func (c *MatchingCache) InvalidateAll() {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+	c.cache = lru.New(c.cache.MaxEntries)
+}