63 lines
1.2 KiB
Go
63 lines
1.2 KiB
Go
// Copyright 2011 The Walk Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build windows
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package walk
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type treeItemEventHandlerInfo struct {
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handler TreeItemEventHandler
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once bool
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}
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type TreeItemEventHandler func(item TreeItem)
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type TreeItemEvent struct {
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handlers []treeItemEventHandlerInfo
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}
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func (e *TreeItemEvent) Attach(handler TreeItemEventHandler) int {
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handlerInfo := treeItemEventHandlerInfo{handler, false}
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for i, h := range e.handlers {
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if h.handler == nil {
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e.handlers[i] = handlerInfo
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return i
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}
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}
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e.handlers = append(e.handlers, handlerInfo)
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return len(e.handlers) - 1
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}
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func (e *TreeItemEvent) Detach(handle int) {
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e.handlers[handle].handler = nil
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}
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func (e *TreeItemEvent) Once(handler TreeItemEventHandler) {
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i := e.Attach(handler)
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e.handlers[i].once = true
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}
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type TreeItemEventPublisher struct {
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event TreeItemEvent
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}
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func (p *TreeItemEventPublisher) Event() *TreeItemEvent {
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return &p.event
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}
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func (p *TreeItemEventPublisher) Publish(item TreeItem) {
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for i, h := range p.event.handlers {
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if h.handler != nil {
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h.handler(item)
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if h.once {
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p.event.Detach(i)
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}
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}
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}
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}
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