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@ -34,6 +34,7 @@ package lru |
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import ( |
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"container/list" |
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"sync" |
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) |
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// Cache is an LRU cache. It is not safe for concurrent access.
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@ -48,6 +49,7 @@ type Cache struct { |
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ll *list.List |
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cache map[interface{}]*list.Element |
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lock *sync.RWMutex |
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} |
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// A Key may be any value that is comparable. See http://golang.org/ref/spec#Comparison_operators
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@ -66,11 +68,14 @@ func New(maxEntries int) *Cache { |
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MaxEntries: maxEntries, |
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ll: list.New(), |
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cache: make(map[interface{}]*list.Element), |
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lock: &sync.RWMutex{}, |
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} |
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} |
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// Add adds a value to the cache.
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func (c *Cache) Add(key Key, value interface{}) { |
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c.lock.Lock() |
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defer c.lock.Unlock() |
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if c.cache == nil { |
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c.cache = make(map[interface{}]*list.Element) |
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c.ll = list.New() |
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@ -89,6 +94,8 @@ func (c *Cache) Add(key Key, value interface{}) { |
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// Get looks up a key's value from the cache.
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func (c *Cache) Get(key Key) (value interface{}, ok bool) { |
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c.lock.Lock() |
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defer c.lock.Unlock() |
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if c.cache == nil { |
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return |
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} |
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@ -101,6 +108,8 @@ func (c *Cache) Get(key Key) (value interface{}, ok bool) { |
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// Remove removes the provided key from the cache.
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func (c *Cache) Remove(key Key) { |
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c.lock.Lock() |
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defer c.lock.Unlock() |
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if c.cache == nil { |
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return |
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} |
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@ -111,6 +120,8 @@ func (c *Cache) Remove(key Key) { |
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// RemoveOldest removes the oldest item from the cache.
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func (c *Cache) RemoveOldest() { |
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c.lock.Lock() |
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defer c.lock.Unlock() |
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if c.cache == nil { |
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return |
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} |
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@ -122,6 +133,8 @@ func (c *Cache) RemoveOldest() { |
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// GetOldest returns the oldest key, value, ok without modifying the lru
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func (c *Cache) GetOldest() (key Key, value interface{}, ok bool) { |
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c.lock.Lock() |
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defer c.lock.Unlock() |
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if c.cache == nil { |
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return nil, nil, false |
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} |
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@ -143,6 +156,8 @@ func (c *Cache) removeElement(e *list.Element) { |
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// Len returns the number of items in the cache.
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func (c *Cache) Len() int { |
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c.lock.Lock() |
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defer c.lock.Unlock() |
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if c.cache == nil { |
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return 0 |
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} |
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