package main

import "C"
import (
	"errors"
	"sync"
)

type ObjectReference int64

var NullObjectReference error = errors.New("Null object reference")

// GoMemoryStore is a int->interface storage structure so that Go pointers are
// never exposed to C code.
type GoMemoryStore struct {
	mtx   sync.RWMutex
	items map[int64]interface{}
	next  int64
}

func NewGoMemoryStore() *GoMemoryStore {
	ret := GoMemoryStore{}
	ret.items = make(map[int64]interface{})
	return &ret
}

func (this *GoMemoryStore) Put(itm interface{}) ObjectReference {
	this.mtx.Lock()
	defer this.mtx.Unlock()

	key := this.next
	this.items[key] = itm
	this.next++
	return ObjectReference(key)
}

func (this *GoMemoryStore) Get(i ObjectReference) (interface{}, bool) {
	this.mtx.RLock()
	defer this.mtx.RUnlock()

	ret, ok := this.items[int64(i)]
	return ret, ok
}

func (this *GoMemoryStore) Delete(i ObjectReference) {
	this.mtx.Lock()
	defer this.mtx.Unlock()

	delete(this.items, int64(i))
}

var gms *GoMemoryStore = nil

func init() {
	gms = NewGoMemoryStore()
}