mirror of https://github.com/mpolden/echoip
59 lines
946 B
Go
59 lines
946 B
Go
package http
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import (
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"container/list"
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"hash/fnv"
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"net"
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"sync"
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)
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type Cache struct {
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capacity int
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mu sync.RWMutex
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entries map[uint64]Response
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keys *list.List
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}
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func NewCache(capacity int) *Cache {
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if capacity < 0 {
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capacity = 0
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}
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keys := list.New()
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return &Cache{
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capacity: capacity,
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entries: make(map[uint64]Response),
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keys: keys,
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}
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}
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func key(ip net.IP) uint64 {
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h := fnv.New64a()
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h.Write(ip)
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return h.Sum64()
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}
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func (c *Cache) Set(ip net.IP, resp Response) {
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if c.capacity == 0 {
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return
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}
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k := key(ip)
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c.mu.Lock()
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defer c.mu.Unlock()
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if len(c.entries) == c.capacity {
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// At capacity. Remove the oldest entry
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oldest := c.keys.Front()
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delete(c.entries, oldest.Value.(uint64))
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c.keys.Remove(oldest)
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}
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c.entries[k] = resp
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c.keys.PushBack(k)
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}
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func (c *Cache) Get(ip net.IP) (Response, bool) {
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k := key(ip)
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c.mu.RLock()
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defer c.mu.RUnlock()
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r, ok := c.entries[k]
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return r, ok
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}
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