BedrockFetch/internal/promise/promise.go

package promise

type Promise struct {
	waits int
	cal   chan error
}

// Add new callback to promise array
func (prm *Promise) Add(t func() error) *Promise {
	prm.waits++
	go func() {
		err := t()
		prm.waits--
		prm.cal <- err
	}()
	return prm
}

func (prm *Promise) Close() {
	close(prm.cal)
}

// Wait process and return error if functions return error
func (prm *Promise) Wait() error {
	var (
		err error
		ok bool
	)
	for prm.waits > 0 {
		err, ok = <- prm.cal
		if !ok || err != nil {
			break
		}
	}
	return err
}

func Create() *Promise {
	prm := Promise{}
	prm.cal = make(chan error)
	prm.waits = 0
	return &prm
}