include systray

src/systray/systray.go

@@ -0,0 +1,233 @@
+/*
+Package systray is a cross-platform Go library to place an icon and menu in the notification area.
+*/
+package systray
+
+import (
+	"fmt"
+	"log"
+	"runtime"
+	"sync"
+	"sync/atomic"
+)
+
+var (
+	systrayReady  func()
+	systrayExit   func()
+	menuItems     = make(map[uint32]*MenuItem)
+	menuItemsLock sync.RWMutex
+
+	currentID = uint32(0)
+	quitOnce  sync.Once
+)
+
+func init() {
+	runtime.LockOSThread()
+}
+
+// MenuItem is used to keep track each menu item of systray.
+// Don't create it directly, use the one systray.AddMenuItem() returned
+type MenuItem struct {
+	// ClickedCh is the channel which will be notified when the menu item is clicked
+	ClickedCh chan struct{}
+
+	// id uniquely identify a menu item, not supposed to be modified
+	id uint32
+	// title is the text shown on menu item
+	title string
+	// tooltip is the text shown when pointing to menu item
+	tooltip string
+	// disabled menu item is grayed out and has no effect when clicked
+	disabled bool
+	// checked menu item has a tick before the title
+	checked bool
+	// has the menu item a checkbox (Linux)
+	isCheckable bool
+	// parent item, for sub menus
+	parent *MenuItem
+}
+
+func (item *MenuItem) String() string {
+	if item.parent == nil {
+		return fmt.Sprintf("MenuItem[%d, %q]", item.id, item.title)
+	}
+	return fmt.Sprintf("MenuItem[%d, parent %d, %q]", item.id, item.parent.id, item.title)
+}
+
+// newMenuItem returns a populated MenuItem object
+func newMenuItem(title string, tooltip string, parent *MenuItem) *MenuItem {
+	return &MenuItem{
+		ClickedCh:   make(chan struct{}),
+		id:          atomic.AddUint32(&currentID, 1),
+		title:       title,
+		tooltip:     tooltip,
+		disabled:    false,
+		checked:     false,
+		isCheckable: false,
+		parent:      parent,
+	}
+}
+
+// Run initializes GUI and starts the event loop, then invokes the onReady
+// callback. It blocks until systray.Quit() is called.
+func Run(onReady func(), onExit func()) {
+	Register(onReady, onExit)
+	nativeLoop()
+}
+
+// Register initializes GUI and registers the callbacks but relies on the
+// caller to run the event loop somewhere else. It's useful if the program
+// needs to show other UI elements, for example, webview.
+// To overcome some OS weirdness, On macOS versions before Catalina, calling
+// this does exactly the same as Run().
+func Register(onReady func(), onExit func()) {
+	if onReady == nil {
+		systrayReady = func() {}
+	} else {
+		// Run onReady on separate goroutine to avoid blocking event loop
+		readyCh := make(chan interface{})
+		go func() {
+			<-readyCh
+			onReady()
+		}()
+		systrayReady = func() {
+			close(readyCh)
+		}
+	}
+	// unlike onReady, onExit runs in the event loop to make sure it has time to
+	// finish before the process terminates
+	if onExit == nil {
+		onExit = func() {}
+	}
+	systrayExit = onExit
+	registerSystray()
+}
+
+// Quit the systray
+func Quit() {
+	quitOnce.Do(quit)
+}
+
+// AddMenuItem adds a menu item with the designated title and tooltip.
+// It can be safely invoked from different goroutines.
+// Created menu items are checkable on Windows and OSX by default. For Linux you have to use AddMenuItemCheckbox
+func AddMenuItem(title string, tooltip string) *MenuItem {
+	item := newMenuItem(title, tooltip, nil)
+	item.update()
+	return item
+}
+
+// AddMenuItemCheckbox adds a menu item with the designated title and tooltip and a checkbox for Linux.
+// It can be safely invoked from different goroutines.
+// On Windows and OSX this is the same as calling AddMenuItem
+func AddMenuItemCheckbox(title string, tooltip string, checked bool) *MenuItem {
+	item := newMenuItem(title, tooltip, nil)
+	item.isCheckable = true
+	item.checked = checked
+	item.update()
+	return item
+}
+
+// AddSeparator adds a separator bar to the menu
+func AddSeparator() {
+	addSeparator(atomic.AddUint32(&currentID, 1))
+}
+
+// AddSubMenuItem adds a nested sub-menu item with the designated title and tooltip.
+// It can be safely invoked from different goroutines.
+// Created menu items are checkable on Windows and OSX by default. For Linux you have to use AddSubMenuItemCheckbox
+func (item *MenuItem) AddSubMenuItem(title string, tooltip string) *MenuItem {
+	child := newMenuItem(title, tooltip, item)
+	child.update()
+	return child
+}
+
+// AddSubMenuItemCheckbox adds a nested sub-menu item with the designated title and tooltip and a checkbox for Linux.
+// It can be safely invoked from different goroutines.
+// On Windows and OSX this is the same as calling AddSubMenuItem
+func (item *MenuItem) AddSubMenuItemCheckbox(title string, tooltip string, checked bool) *MenuItem {
+	child := newMenuItem(title, tooltip, item)
+	child.isCheckable = true
+	child.checked = checked
+	child.update()
+	return child
+}
+
+// SetTitle set the text to display on a menu item
+func (item *MenuItem) SetTitle(title string) {
+	item.title = title
+	item.update()
+}
+
+// SetTooltip set the tooltip to show when mouse hover
+func (item *MenuItem) SetTooltip(tooltip string) {
+	item.tooltip = tooltip
+	item.update()
+}
+
+// Disabled checks if the menu item is disabled
+func (item *MenuItem) Disabled() bool {
+	return item.disabled
+}
+
+// Enable a menu item regardless if it's previously enabled or not
+func (item *MenuItem) Enable() {
+	item.disabled = false
+	item.update()
+}
+
+// Disable a menu item regardless if it's previously disabled or not
+func (item *MenuItem) Disable() {
+	item.disabled = true
+	item.update()
+}
+
+// Hide hides a menu item
+func (item *MenuItem) Hide() {
+	hideMenuItem(item)
+}
+
+// Show shows a previously hidden menu item
+func (item *MenuItem) Show() {
+	showMenuItem(item)
+}
+
+// Checked returns if the menu item has a check mark
+func (item *MenuItem) Checked() bool {
+	return item.checked
+}
+
+// Check a menu item regardless if it's previously checked or not
+func (item *MenuItem) Check() {
+	item.checked = true
+	item.update()
+}
+
+// Uncheck a menu item regardless if it's previously unchecked or not
+func (item *MenuItem) Uncheck() {
+	item.checked = false
+	item.update()
+}
+
+// update propagates changes on a menu item to systray
+func (item *MenuItem) update() {
+	menuItemsLock.Lock()
+	menuItems[item.id] = item
+	menuItemsLock.Unlock()
+	addOrUpdateMenuItem(item)
+}
+
+func systrayMenuItemSelected(id uint32) {
+	menuItemsLock.RLock()
+	item, ok := menuItems[id]
+	menuItemsLock.RUnlock()
+	if !ok {
+		log.Printf("No menu item with ID %v", id)
+		return
+	}
+	select {
+	case item.ClickedCh <- struct{}{}:
+	// in case no one waiting for the channel
+	default:
+	}
+}