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48 lines
1.2 KiB
48 lines
1.2 KiB
// package cache implements a really primitive cache that associates expiring
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// values with string keys. This cache never clears itself out.
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package main
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import (
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"sync"
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"time"
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)
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// Cache is a cache for binary data
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type Cache struct {
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entries map[string]*entry
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mutex sync.RWMutex
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}
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// entry is an entry in a Cache
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type entry struct {
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data interface{}
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expiration time.Time
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}
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// NewCache creates a new Cache
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func NewCache() *Cache {
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return &Cache{entries: make(map[string]*entry)}
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}
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// Get returns the currently cached value for the given key, as long as it
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// hasn't expired. If the key was never set, or has expired, found will be
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// false.
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func (cache *Cache) Get(key string) (val interface{}, found bool) {
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cache.mutex.RLock()
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defer cache.mutex.RUnlock()
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entry := cache.entries[key]
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if entry == nil {
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return nil, false
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} else if entry.expiration.Before(time.Now()) {
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return nil, false
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} else {
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return entry.data, true
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}
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}
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// Set sets a value in the cache with an expiration of now + ttl.
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func (cache *Cache) Set(key string, data interface{}, ttl time.Duration) {
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cache.mutex.Lock()
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defer cache.mutex.Unlock()
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cache.entries[key] = &entry{data, time.Now().Add(ttl)}
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}
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