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vendor/k8s.io/apimachinery/pkg/util/cache/cache.go

@@ -0,0 +1,83 @@
+/*
+Copyright 2014 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 cache
+
+import (
+	"sync"
+)
+
+const (
+	shardsCount int = 32
+)
+
+type Cache []*cacheShard
+
+func NewCache(maxSize int) Cache {
+	if maxSize < shardsCount {
+		maxSize = shardsCount
+	}
+	cache := make(Cache, shardsCount)
+	for i := 0; i < shardsCount; i++ {
+		cache[i] = &cacheShard{
+			items:   make(map[uint64]interface{}),
+			maxSize: maxSize / shardsCount,
+		}
+	}
+	return cache
+}
+
+func (c Cache) getShard(index uint64) *cacheShard {
+	return c[index%uint64(shardsCount)]
+}
+
+// Returns true if object already existed, false otherwise.
+func (c *Cache) Add(index uint64, obj interface{}) bool {
+	return c.getShard(index).add(index, obj)
+}
+
+func (c *Cache) Get(index uint64) (obj interface{}, found bool) {
+	return c.getShard(index).get(index)
+}
+
+type cacheShard struct {
+	items map[uint64]interface{}
+	sync.RWMutex
+	maxSize int
+}
+
+// Returns true if object already existed, false otherwise.
+func (s *cacheShard) add(index uint64, obj interface{}) bool {
+	s.Lock()
+	defer s.Unlock()
+	_, isOverwrite := s.items[index]
+	if !isOverwrite && len(s.items) >= s.maxSize {
+		var randomKey uint64
+		for randomKey = range s.items {
+			break
+		}
+		delete(s.items, randomKey)
+	}
+	s.items[index] = obj
+	return isOverwrite
+}
+
+func (s *cacheShard) get(index uint64) (obj interface{}, found bool) {
+	s.RLock()
+	defer s.RUnlock()
+	obj, found = s.items[index]
+	return
+}

vendor/k8s.io/apimachinery/pkg/util/cache/lruexpirecache.go

@@ -0,0 +1,102 @@
+/*
+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 cache
+
+import (
+	"sync"
+	"time"
+
+	"github.com/hashicorp/golang-lru"
+)
+
+// Clock defines an interface for obtaining the current time
+type Clock interface {
+	Now() time.Time
+}
+
+// realClock implements the Clock interface by calling time.Now()
+type realClock struct{}
+
+func (realClock) Now() time.Time { return time.Now() }
+
+// LRUExpireCache is a cache that ensures the mostly recently accessed keys are returned with
+// a ttl beyond which keys are forcibly expired.
+type LRUExpireCache struct {
+	// clock is used to obtain the current time
+	clock Clock
+
+	cache *lru.Cache
+	lock  sync.Mutex
+}
+
+// NewLRUExpireCache creates an expiring cache with the given size
+func NewLRUExpireCache(maxSize int) *LRUExpireCache {
+	return NewLRUExpireCacheWithClock(maxSize, realClock{})
+}
+
+// NewLRUExpireCacheWithClock creates an expiring cache with the given size, using the specified clock to obtain the current time.
+func NewLRUExpireCacheWithClock(maxSize int, clock Clock) *LRUExpireCache {
+	cache, err := lru.New(maxSize)
+	if err != nil {
+		// if called with an invalid size
+		panic(err)
+	}
+	return &LRUExpireCache{clock: clock, cache: cache}
+}
+
+type cacheEntry struct {
+	value      interface{}
+	expireTime time.Time
+}
+
+// Add adds the value to the cache at key with the specified maximum duration.
+func (c *LRUExpireCache) Add(key interface{}, value interface{}, ttl time.Duration) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.cache.Add(key, &cacheEntry{value, c.clock.Now().Add(ttl)})
+}
+
+// Get returns the value at the specified key from the cache if it exists and is not
+// expired, or returns false.
+func (c *LRUExpireCache) Get(key interface{}) (interface{}, bool) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	e, ok := c.cache.Get(key)
+	if !ok {
+		return nil, false
+	}
+	if c.clock.Now().After(e.(*cacheEntry).expireTime) {
+		c.cache.Remove(key)
+		return nil, false
+	}
+	return e.(*cacheEntry).value, true
+}
+
+// Remove removes the specified key from the cache if it exists
+func (c *LRUExpireCache) Remove(key interface{}) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.cache.Remove(key)
+}
+
+// Keys returns all the keys in the cache, even if they are expired. Subsequent calls to
+// get may return not found. It returns all keys from oldest to newest.
+func (c *LRUExpireCache) Keys() []interface{} {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	return c.cache.Keys()
+}