package main

import (
	"fmt"
	"time"
)

const NUM_ELEMENTS = 1000000

type HeavyThings = map[int][]int

func main() {
	heavy_things_1 := make_heavy_things()
	heavy_things_2 := make_heavy_things()
	len := log_time("drop in another thread", func() int {
		tmp := heavy_things_2
		heavy_things_2 = nil
		return fn_that_drops_heavy_things_in_another_thread(tmp)
	})
	if len != NUM_ELEMENTS {
		panic("...")
	}
	len = log_time("drop in this thread", func() int {
		tmp := heavy_things_1
		heavy_things_1 = nil
		return fn_that_drops_heavy_things(tmp)
	})
	if len != NUM_ELEMENTS {
		panic("...")
	}
}

func make_heavy_things() *HeavyThings {
	ret := HeavyThings{}
	for i := int(0); i != NUM_ELEMENTS; i++ {
		ret[i] = []int{i}
	}
	return &ret
}

func fn_that_drops_heavy_things_in_another_thread(things *HeavyThings) int {
	len := len(*things)
	go func() {
		things = nil
	}()
	return len
}

func fn_that_drops_heavy_things(things *HeavyThings) int {
	len := len(*things)
	return len
}

func log_time(name string, f func() int) int {
	start := time.Now()
	result := f()
	fmt.Printf("%v %v\n", name, time.Now().Sub(start))
	return result
}