package main
import (
"sync/atomic"
"unsafe"
)
func newLockFreeCache() lockFreeCache {
ptr := unsafe.Pointer(new(map[string]string))
cache := lockFreeCache{
ptr: &ptr,
}
return cache
}
type lockFreeCache struct {
ptr *unsafe.Pointer
}
func (cache lockFreeCache) read(key string) (string, bool) {
v := (*map[string]string)(atomic.LoadPointer(cache.ptr))
value, ok := (*v)[key]
return value, ok
}
func (cache lockFreeCache) write(key, value string) {
v := (*map[string]string)(atomic.LoadPointer(cache.ptr))
nm := make(map[string]string)
for k, v := range *v {
nm[k] = v
}
nm[key] = value
nmptr := unsafe.Pointer(&nm)
atomic.StorePointer(cache.ptr, nmptr)
}
func main() {
cache := newLockFreeCache()
cache.write("key", "YEAH~!")
val, _ := cache.read("key")
println(val)
}
