cache

README

cache

• lru: 最近没使用的换出缓存
• map: 普通key-value缓存

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) *LRUCache
  • func (lru *LRUCache) Capacity() int64
  • func (lru *LRUCache) Clear()
  • func (lru *LRUCache) Delete(key interface{}) bool
  • func (lru *LRUCache) Evictions() int64
  • func (lru *LRUCache) Get(key interface{}) (v Value, ok bool)
  • func (lru *LRUCache) Init(capacity int64)
  • func (lru *LRUCache) Items() []Item
  • func (lru *LRUCache) Keys() []interface{}
  • func (lru *LRUCache) Length() int64
  • func (lru *LRUCache) Peek(key interface{}) (v Value, ok bool)
  • func (lru *LRUCache) Set(key interface{}, value Value)
  • func (lru *LRUCache) SetAndGetRemoved(key interface{}, value Value) (removedValueList []Value)
  • func (lru *LRUCache) SetCapacity(capacity int64)
  • func (lru *LRUCache) SetIfAbsent(key interface{}, value Value)
  • func (lru *LRUCache) Size() int64
  • func (lru *LRUCache) Stats() (length, size, capacity, evictions int64)
  • func (lru *LRUCache) StatsJSON() string
• type Map
  • func NewMap() *Map
  • func (m *Map) Delete(key interface{})
  • func (m *Map) Exist(key interface{}) bool
  • func (m *Map) Get(key interface{}) (interface{}, bool)
  • func (m *Map) Init()
  • func (m *Map) Set(key interface{}, value interface{})
• type Value

Types

type Item

type Item struct {
	Key   interface{}
	Value Value
}

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 Size() of each item.

func NewLRUCache

func NewLRUCache(capacity int64) *LRUCache

NewLRUCache creates a new empty cache with the given capacity.

func (*LRUCache) Capacity

func (lru *LRUCache) Capacity() int64

Capacity returns the cache maximum capacity.

func (*LRUCache) Clear

func (lru *LRUCache) Clear()

Clear will clear the entire cache.

func (*LRUCache) Delete

func (lru *LRUCache) Delete(key interface{}) bool

Delete removes an entry from the cache, and returns if the entry existed.

func (*LRUCache) Evictions

func (lru *LRUCache) Evictions() int64

Evictions returns the eviction count.

func (*LRUCache) Get

func (lru *LRUCache) Get(key interface{}) (v Value, ok bool)

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

func (*LRUCache) Init

func (lru *LRUCache) Init(capacity int64)

Init : init memory

func (*LRUCache) Items

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

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

func (*LRUCache) Keys

func (lru *LRUCache) Keys() []interface{}

Keys returns all the keys for the cache, ordered from most recently used to last recently used.

func (*LRUCache) Length

func (lru *LRUCache) Length() int64

Length returns how many elements are in the cache

func (*LRUCache) Peek

func (lru *LRUCache) Peek(key interface{}) (v Value, ok bool)

Peek returns a value from the cache without changing the LRU order.

func (*LRUCache) Set

func (lru *LRUCache) Set(key interface{}, value Value)

Set sets a value in the cache.

func (*LRUCache) SetAndGetRemoved

func (lru *LRUCache) SetAndGetRemoved(key interface{}, value Value) (removedValueList []Value)

SetAndGetRemoved sets a value in the cache and returns the removed value list

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) SetIfAbsent

func (lru *LRUCache) SetIfAbsent(key interface{}, value Value)

SetIfAbsent will set the value in the cache if not present. If the value exists in the cache, we don't set it.

func (*LRUCache) Size

func (lru *LRUCache) Size() int64

Size returns the sum of the objects' Size() method.

func (*LRUCache) Stats

func (lru *LRUCache) Stats() (length, size, capacity, evictions int64)

Stats returns a few stats on the cache.

func (*LRUCache) StatsJSON

func (lru *LRUCache) StatsJSON() string

StatsJSON returns stats as a JSON object in a string.

type Map

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

Map with locked map

func NewMap

func NewMap() *Map

func (*Map) Delete

func (m *Map) Delete(key interface{})

func (*Map) Exist

func (m *Map) Exist(key interface{}) bool

func (*Map) Get

func (m *Map) Get(key interface{}) (interface{}, bool)

func (*Map) Init

func (m *Map) Init()

func (*Map) Set

func (m *Map) Set(key interface{}, value interface{})

type Value

type Value interface {
	// Size returns how big this value is. If you want to just track
	// the cache by number of objects, you may return the size as 1.
	Size() int
}

Value is the interface values that go into LRUCache need to satisfy