diff options
Diffstat (limited to 'Godeps/_workspace/src/github.com/hashicorp/golang-lru/simplelru/lru.go')
-rw-r--r-- | Godeps/_workspace/src/github.com/hashicorp/golang-lru/simplelru/lru.go | 160 |
1 files changed, 0 insertions, 160 deletions
diff --git a/Godeps/_workspace/src/github.com/hashicorp/golang-lru/simplelru/lru.go b/Godeps/_workspace/src/github.com/hashicorp/golang-lru/simplelru/lru.go deleted file mode 100644 index 68d097a1c..000000000 --- a/Godeps/_workspace/src/github.com/hashicorp/golang-lru/simplelru/lru.go +++ /dev/null @@ -1,160 +0,0 @@ -package simplelru - -import ( - "container/list" - "errors" -) - -// EvictCallback is used to get a callback when a cache entry is evicted -type EvictCallback func(key interface{}, value interface{}) - -// LRU implements a non-thread safe fixed size LRU cache -type LRU struct { - size int - evictList *list.List - items map[interface{}]*list.Element - onEvict EvictCallback -} - -// entry is used to hold a value in the evictList -type entry struct { - key interface{} - value interface{} -} - -// NewLRU constructs an LRU of the given size -func NewLRU(size int, onEvict EvictCallback) (*LRU, error) { - if size <= 0 { - return nil, errors.New("Must provide a positive size") - } - c := &LRU{ - size: size, - evictList: list.New(), - items: make(map[interface{}]*list.Element), - onEvict: onEvict, - } - return c, nil -} - -// Purge is used to completely clear the cache -func (c *LRU) Purge() { - for k, v := range c.items { - if c.onEvict != nil { - c.onEvict(k, v.Value.(*entry).value) - } - delete(c.items, k) - } - c.evictList.Init() -} - -// Add adds a value to the cache. Returns true if an eviction occured. -func (c *LRU) Add(key, value interface{}) bool { - // Check for existing item - if ent, ok := c.items[key]; ok { - c.evictList.MoveToFront(ent) - ent.Value.(*entry).value = value - return false - } - - // Add new item - ent := &entry{key, value} - entry := c.evictList.PushFront(ent) - c.items[key] = entry - - evict := c.evictList.Len() > c.size - // Verify size not exceeded - if evict { - c.removeOldest() - } - return evict -} - -// Get looks up a key's value from the cache. -func (c *LRU) Get(key interface{}) (value interface{}, ok bool) { - if ent, ok := c.items[key]; ok { - c.evictList.MoveToFront(ent) - return ent.Value.(*entry).value, true - } - return -} - -// Check if a key is in the cache, without updating the recent-ness -// or deleting it for being stale. -func (c *LRU) Contains(key interface{}) (ok bool) { - _, ok = c.items[key] - return ok -} - -// Returns the key value (or undefined if not found) without updating -// the "recently used"-ness of the key. -func (c *LRU) Peek(key interface{}) (value interface{}, ok bool) { - if ent, ok := c.items[key]; ok { - return ent.Value.(*entry).value, true - } - return nil, ok -} - -// Remove removes the provided key from the cache, returning if the -// key was contained. -func (c *LRU) Remove(key interface{}) bool { - if ent, ok := c.items[key]; ok { - c.removeElement(ent) - return true - } - return false -} - -// RemoveOldest removes the oldest item from the cache. -func (c *LRU) RemoveOldest() (interface{}, interface{}, bool) { - ent := c.evictList.Back() - if ent != nil { - c.removeElement(ent) - kv := ent.Value.(*entry) - return kv.key, kv.value, true - } - return nil, nil, false -} - -// GetOldest returns the oldest entry -func (c *LRU) GetOldest() (interface{}, interface{}, bool) { - ent := c.evictList.Back() - if ent != nil { - kv := ent.Value.(*entry) - return kv.key, kv.value, true - } - return nil, nil, false -} - -// Keys returns a slice of the keys in the cache, from oldest to newest. -func (c *LRU) Keys() []interface{} { - keys := make([]interface{}, len(c.items)) - i := 0 - for ent := c.evictList.Back(); ent != nil; ent = ent.Prev() { - keys[i] = ent.Value.(*entry).key - i++ - } - return keys -} - -// Len returns the number of items in the cache. -func (c *LRU) Len() int { - return c.evictList.Len() -} - -// removeOldest removes the oldest item from the cache. -func (c *LRU) removeOldest() { - ent := c.evictList.Back() - if ent != nil { - c.removeElement(ent) - } -} - -// removeElement is used to remove a given list element from the cache -func (c *LRU) removeElement(e *list.Element) { - c.evictList.Remove(e) - kv := e.Value.(*entry) - delete(c.items, kv.key) - if c.onEvict != nil { - c.onEvict(kv.key, kv.value) - } -} |