Use buffered channel to limit number of goroutines spawned

buffpool.go

type goPool struct {
    hold sync.WaitGroup
    work chan func()
    ready chan bool
}

func newGoPool(jobs uint) *goPool {
    pool := &goPool{}
    pool.ready = make(chan bool, jobs)
    pool.work = make(chan func())
    for i := uint(0); i < jobs; i++ {
        pool.ready<- true
    }
    return pool
}

func (pool *goPool) run() {
    go func() {
        for range pool.ready {
            f := <-pool.work
            go func() {
                f()
                pool.ready<- true
            }()
        }
    }()
}

func (pool *goPool) add(f func()) {
    pool.hold.Add(1)
    pool.work<- func() {
        f()
        pool.hold.Done()
    }
}

func (pool *goPool) wait() {
    pool.hold.Wait()
    close(pool.work)
    close(pool.ready)
}

ready should be closed by run. Only run knows when it is out of work.