Xray-core/common/cache/lru.go

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package cache
import (
"container/list"
"sync"
)
// Lru simple, fast lru cache implementation
type Lru interface {
Get(key interface{}) (value interface{}, ok bool)
GetKeyFromValue(value interface{}) (key interface{}, ok bool)
PeekKeyFromValue(value interface{}) (key interface{}, ok bool) // Peek means check but NOT bring to top
Put(key, value interface{})
}
type lru struct {
capacity int
doubleLinkedlist *list.List
keyToElement *sync.Map
valueToElement *sync.Map
mu *sync.Mutex
}
type lruElement struct {
key interface{}
value interface{}
}
2022-01-13 04:51:47 +02:00
// NewLru initializes a lru cache
func NewLru(cap int) Lru {
return &lru{
capacity: cap,
doubleLinkedlist: list.New(),
keyToElement: new(sync.Map),
valueToElement: new(sync.Map),
mu: new(sync.Mutex),
}
}
func (l *lru) Get(key interface{}) (value interface{}, ok bool) {
l.mu.Lock()
defer l.mu.Unlock()
if v, ok := l.keyToElement.Load(key); ok {
element := v.(*list.Element)
l.doubleLinkedlist.MoveToFront(element)
return element.Value.(*lruElement).value, true
}
return nil, false
}
func (l *lru) GetKeyFromValue(value interface{}) (key interface{}, ok bool) {
l.mu.Lock()
defer l.mu.Unlock()
if k, ok := l.valueToElement.Load(value); ok {
element := k.(*list.Element)
l.doubleLinkedlist.MoveToFront(element)
return element.Value.(*lruElement).key, true
}
return nil, false
}
func (l *lru) PeekKeyFromValue(value interface{}) (key interface{}, ok bool) {
if k, ok := l.valueToElement.Load(value); ok {
element := k.(*list.Element)
return element.Value.(*lruElement).key, true
}
return nil, false
}
func (l *lru) Put(key, value interface{}) {
l.mu.Lock()
e := &lruElement{key, value}
if v, ok := l.keyToElement.Load(key); ok {
element := v.(*list.Element)
element.Value = e
l.doubleLinkedlist.MoveToFront(element)
} else {
element := l.doubleLinkedlist.PushFront(e)
l.keyToElement.Store(key, element)
l.valueToElement.Store(value, element)
if l.doubleLinkedlist.Len() > l.capacity {
toBeRemove := l.doubleLinkedlist.Back()
l.doubleLinkedlist.Remove(toBeRemove)
l.keyToElement.Delete(toBeRemove.Value.(*lruElement).key)
l.valueToElement.Delete(toBeRemove.Value.(*lruElement).value)
}
}
l.mu.Unlock()
}