cache

Documentation

Overview

Package cache implements a LRU cache.

The implementation borrows heavily from SmallLRUCache (originally by Nathan Schrenk). The object maintains a doubly-linked list of elements. When an element is accessed, it is promoted to the head of the list. When space is needed, the element at the tail of the list (the least recently used element) is evicted.

Index

• type Item
• type LRUCache
  • func NewLRUCache(capacity int64, cost func(any) int64) *LRUCache
  • func (lru *LRUCache) Clear()
  • func (lru *LRUCache) Close()
  • func (lru *LRUCache) Delete(key string)
  • func (lru *LRUCache) Evictions() int64
  • func (lru *LRUCache) ForEach(callback func(value any) bool)
  • func (lru *LRUCache) Get(key string) (v any, ok bool)
  • func (lru *LRUCache) Hits() int64
  • func (lru *LRUCache) Items() []Item
  • func (lru *LRUCache) Len() int
  • func (lru *LRUCache) MaxCapacity() int64
  • func (lru *LRUCache) Misses() int64
  • func (lru *LRUCache) Set(key string, value any) bool
  • func (lru *LRUCache) SetCapacity(capacity int64)
  • func (lru *LRUCache) UsedCapacity() int64
  • func (lru *LRUCache) Wait()

Types

type Item

type Item struct {
	Key   string
	Value any
}

Item is what is stored in the cache

type LRUCache

type LRUCache struct {
	// contains filtered or unexported fields
}

LRUCache is a typical LRU cache implementation. If the cache reaches the capacity, the least recently used item is deleted from the cache. Note the capacity is not the number of items, but the total sum of the CachedSize() of each item.

func NewLRUCache

func NewLRUCache(capacity int64, cost func(any) int64) *LRUCache

NewLRUCache creates a new empty cache with the given capacity.

func (*LRUCache) Clear

func (lru *LRUCache) Clear()

Clear will clear the entire cache.

func (*LRUCache) Close

func (lru *LRUCache) Close()

func (*LRUCache) Delete

func (lru *LRUCache) Delete(key string)

Delete removes an entry from the cache

func (*LRUCache) Evictions

func (lru *LRUCache) Evictions() int64

Evictions returns the number of evictions

func (*LRUCache) ForEach

func (lru *LRUCache) ForEach(callback func(value any) bool)

ForEach yields all the values for the cache, ordered from most recently used to least recently used.

func (*LRUCache) Get

func (lru *LRUCache) Get(key string) (v any, ok bool)

Get returns a value from the cache, and marks the entry as most recently used.

func (*LRUCache) Hits

func (lru *LRUCache) Hits() int64

Hits returns number of cache hits since creation

func (*LRUCache) Items

func (lru *LRUCache) Items() []Item

Items returns all the values for the cache, ordered from most recently used to least recently used.

func (*LRUCache) Len

func (lru *LRUCache) Len() int

Len returns the size of the cache (in entries)

func (*LRUCache) MaxCapacity

func (lru *LRUCache) MaxCapacity() int64

MaxCapacity returns the cache maximum capacity.

func (*LRUCache) Misses

func (lru *LRUCache) Misses() int64

Misses returns number of cache misses since creation

func (*LRUCache) Set

func (lru *LRUCache) Set(key string, value any) bool

Set sets a value in the cache.

func (*LRUCache) SetCapacity

func (lru *LRUCache) SetCapacity(capacity int64)

SetCapacity will set the capacity of the cache. If the capacity is smaller, and the current cache size exceed that capacity, the cache will be shrank.

func (*LRUCache) UsedCapacity

func (lru *LRUCache) UsedCapacity() int64

UsedCapacity returns the size of the cache (in bytes)

func (*LRUCache) Wait

func (lru *LRUCache) Wait()

Wait is a no-op in the LRU cache