Weakref

Feature

• Weakref for golang
• Support weakref map (weak value)
• Check if value available

Usage

type WeakRef

A weakref instance

func WeakRef.Ok

func (*WeakRef)Ok()(bool)

Check if this weakref is available

func WeakRef.Value

func (*WeakRef)Value()(interface{})

Get the value of the weakref

func NewWeakRef

func NewWeakRef(ptr interface{})(w *WeakRef)

Create a instance of weakref.WeakRef, ptr must be a type of pointer or unsafe.Pointer

type Map

A weak value map, if the value is not available, the map will auto remove the key
The map is theard safty

func Map.Len

func (*Map)Len()()

func Map.Has

func (*Map)Has(k interface{})(bool)

Check if key-value exists

func Map.Get

func (*Map)Get(k interface{})(interface{})

Get value of key

func Map.Set

func (*Map)Set(k interface{}, v interface{})(interface{})

Set value of key, and return the value

func Map.GetOrSet

func (*Map)GetOrSet(k interface{}, setter func()(interface{}))(interface{})

Get value of key, if key not exists, set the value returned by setter, and return the value

func Map.Pop

func (*Map)Pop(k interface{})(interface{})

Remove value of the key, and return the value

func Map.Reset

func (*Map)Reset()

Reset the map (clear all of the key-value)

func Map.AsMap

func (*Map)AsMap()(map[interface{}]interface{})

Create a new builtin.map, and copy all the key-value from weakref.Map

func NewMap

func NewMap()(*Map)

Create a new empty weakref.Map

Example for weakref.WeakRef:

import (
	weakref "github.com/zyxkad/weakref"
)

type T struct{
	id int
	name string
}

var global_cache_t *weakref.WeakRef

func GetT()(*T){
	if global_cache_t.Ok(){ // If this weakref is available
		return global_cache_t.Value().(*T) // type assertion
	}
	t := &T{
		id: 1,
		name: "name",
	}

	global_cache_t = weakref.NewWeakRef(t) // create a new weakref

	return t
}

// ...

func main(){
	for {
		// ...
		if true {
			t := GetT()
			do_something_with_t(t)
		}
		// ...
	}
}

Example for weakref.Map:

import (
	weakref "github.com/zyxkad/weakref"
)

type User struct{
	name string
	score int
}

var weak_cache *weakref.Map = weakref.NewMap()

func ReadUserFromFile(name string)(u *User){
	// ...
	return
}

func GetUser(name string)(*User){
	return weak_cache.GetOrSet(name, func()(interface{}){
		return ReadUserFromFile(name)
	}).(*User)
}


func main(){
	for {
		// ...
		{
			a := GetUser("a")
			a.score++
			SaveUser(a)
		}
		{
			b := GetUser("b")
			b.score--
			SaveUser(b)
		}
		// ...
}