event.go

// Copyright 2011 The Walk Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// +build windows

package walk

type EventHandler func()

type Event struct {
	handlers []EventHandler
}

func (e *Event) Attach(handler EventHandler) int {
	for i, h := range e.handlers {
		if h == nil {
			e.handlers[i] = handler
			return i
		}
	}

	e.handlers = append(e.handlers, handler)
	return len(e.handlers) - 1
}

func (e *Event) Detach(handle int) {
	e.handlers[handle] = nil
}

type EventPublisher struct {
	event Event
}

func (p *EventPublisher) Event() *Event {
	return &p.event
}

func (p *EventPublisher) Publish() {
	events := inProgressEventsByForm[appSingleton.activeForm]
	events = append(events, &p.event)
	inProgressEventsByForm[appSingleton.activeForm] = events

	defer func() {
		events = events[:len(events)-1]
		if len(events) == 0 {
			delete(inProgressEventsByForm, appSingleton.activeForm)
		} else {
			inProgressEventsByForm[appSingleton.activeForm] = events
			return
		}

		performScheduledLayouts()
	}()

	for _, handler := range p.event.handlers {
		if handler != nil {
			handler()
		}
	}
}