73 lines
1.2 KiB
Go
73 lines
1.2 KiB
Go
package nixmsg
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import "container/list"
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type lruEntry struct {
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key string
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val any
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}
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// lruCache 固定容量 LRU，删除时同步移除链表节点。
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type lruCache struct {
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cap int
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ll *list.List
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m map[string]*list.Element
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}
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func newLRU(cap int) *lruCache {
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if cap <= 0 {
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cap = 10000
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}
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return &lruCache{
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cap: cap,
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ll: list.New(),
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m: make(map[string]*list.Element),
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}
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}
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func (c *lruCache) Get(key string) (any, bool) {
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el, ok := c.m[key]
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if !ok {
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return nil, false
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}
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c.ll.MoveToFront(el)
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return el.Value.(*lruEntry).val, true
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}
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func (c *lruCache) Put(key string, val any) {
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if el, ok := c.m[key]; ok {
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el.Value.(*lruEntry).val = val
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c.ll.MoveToFront(el)
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return
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}
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el := c.ll.PushFront(&lruEntry{key: key, val: val})
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c.m[key] = el
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for c.ll.Len() > c.cap {
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back := c.ll.Back()
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if back == nil {
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break
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}
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ent := back.Value.(*lruEntry)
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c.ll.Remove(back)
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delete(c.m, ent.key)
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}
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}
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func (c *lruCache) Delete(key string) {
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el, ok := c.m[key]
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if !ok {
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return
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}
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c.ll.Remove(el)
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delete(c.m, key)
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}
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func (c *lruCache) Len() int {
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return c.ll.Len()
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}
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func (c *lruCache) Has(key string) bool {
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_, ok := c.m[key]
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return ok
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}
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