cmd/systray: rebuild menu on pref change, assorted other fixes

- rebuild menu when prefs change outside of systray, such as setting an
  exit node
- refactor onClick handler code
- compare lowercase country name, the same as macOS and Windows (now
  sorts Ukraine before USA)
- fix "connected / disconnected" menu items on stopped status
- prevent nil pointer on "This Device" menu item

Updates #1708

Change-Id: Ia101a4a3005adb9118051b3416f5a64a4a45987d
Signed-off-by: Will Norris <will@tailscale.com>

cmd/systray/systray.go

@@ -7,7 +7,6 @@
 package main
 
 import (
-	"cmp"
 	"context"
 	"errors"
 	"fmt"
@@ -30,12 +29,15 @@ import (
 	"tailscale.com/ipn"
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/tailcfg"
+	"tailscale.com/util/stringsx"
 )
 
 var (
 	localClient tailscale.LocalClient
 	chState     chan ipn.State // tailscale state changes
 
+	chRebuild chan struct{} // triggers a menu rebuild
+
 	appIcon *os.File
 
 	// newMenuDelay is the amount of time to sleep after creating a new menu,
@@ -111,6 +113,7 @@ func onReady() {
 	io.Copy(appIcon, connected.renderWithBorder(3))
 
 	chState = make(chan ipn.State, 1)
+	chRebuild = make(chan struct{}, 1)
 
 	menu := new(Menu)
 	menu.rebuild(fetchState(ctx))
@@ -146,6 +149,10 @@ func fetchState(ctx context.Context) state {
 // You cannot iterate over the items in a menu, nor can you remove some items like separators.
 // So for now we rebuild the whole thing, and can optimize this later if needed.
 func (menu *Menu) rebuild(state state) {
+	if state.status == nil {
+		return
+	}
+
 	menu.mu.Lock()
 	defer menu.mu.Unlock()
 
@@ -181,25 +188,20 @@ func (menu *Menu) rebuild(state state) {
 			item = accounts.AddSubMenuItem(title, "")
 		}
 		setRemoteIcon(item, profile.UserProfile.ProfilePicURL)
-		go func(profile ipn.LoginProfile) {
+		onClick(ctx, item, func(ctx context.Context) {
-			for {
 			select {
 			case <-ctx.Done():
-					return
-				case <-item.ClickedCh:
-					select {
-					case <-ctx.Done():
-						return
 			case menu.accountsCh <- profile.ID:
 			}
-				}
+		})
-			}
-		}(profile)
 	}
 
-	if state.status != nil && state.status.Self != nil {
+	if state.status != nil && state.status.Self != nil && len(state.status.Self.TailscaleIPs) > 0 {
 		title := fmt.Sprintf("This Device: %s (%s)", state.status.Self.HostName, state.status.Self.TailscaleIPs[0])
 		menu.self = systray.AddMenuItem(title, "")
+	} else {
+		menu.self = systray.AddMenuItem("This Device: not connected", "")
+		menu.self.Disable()
 	}
 	systray.AddSeparator()
 
@@ -266,6 +268,8 @@ func (menu *Menu) eventLoop(ctx context.Context) {
 		select {
 		case <-ctx.Done():
 			return
+		case <-chRebuild:
+			menu.rebuild(fetchState(ctx))
 		case state := <-chState:
 			switch state {
 			case ipn.Running:
@@ -277,10 +281,11 @@ func (menu *Menu) eventLoop(ctx context.Context) {
 				menu.disconnect.Show()
 				menu.disconnect.Enable()
 			case ipn.NoState, ipn.Stopped:
+				setAppIcon(disconnected)
+				menu.rebuild(fetchState(ctx))
 				menu.connect.SetTitle("Connect")
 				menu.connect.Enable()
 				menu.disconnect.Hide()
-				setAppIcon(disconnected)
 			case ipn.Starting:
 				setAppIcon(loading)
 			}
@@ -337,7 +342,6 @@ func (menu *Menu) eventLoop(ctx context.Context) {
 					log.Printf("failed setting exit node: %v", err)
 				}
 			}
-			menu.rebuild(fetchState(ctx))
 
 		case <-menu.quit.ClickedCh:
 			systray.Quit()
@@ -345,6 +349,20 @@ func (menu *Menu) eventLoop(ctx context.Context) {
 	}
 }
 
+// onClick registers a click handler for a menu item.
+func onClick(ctx context.Context, item *systray.MenuItem, fn func(ctx context.Context)) {
+	go func() {
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case <-item.ClickedCh:
+				fn(ctx)
+			}
+		}
+	}()
+}
+
 // watchIPNBus subscribes to the tailscale event bus and sends state updates to chState.
 // This method does not return.
 func watchIPNBus(ctx context.Context) {
@@ -383,6 +401,9 @@ func watchIPNBusInner(ctx context.Context) error {
 				chState <- *n.State
 				log.Printf("new state: %v", n.State)
 			}
+			if n.Prefs != nil {
+				chRebuild <- struct{}{}
+			}
 		}
 	}
 }
@@ -425,25 +446,17 @@ func (menu *Menu) rebuildExitNodeMenu(ctx context.Context) {
 	time.Sleep(newMenuDelay)
 
 	// register a click handler for a menu item to set nodeID as the exit node.
-	onClick := func(item *systray.MenuItem, nodeID tailcfg.StableNodeID) {
+	setExitNodeOnClick := func(item *systray.MenuItem, nodeID tailcfg.StableNodeID) {
-		go func() {
+		onClick(ctx, item, func(ctx context.Context) {
-			for {
 			select {
 			case <-ctx.Done():
-					return
-				case <-item.ClickedCh:
-					select {
-					case <-ctx.Done():
-						return
 			case menu.exitNodeCh <- nodeID:
 			}
-				}
+		})
-			}
-		}()
 	}
 
 	noExitNodeMenu := menu.exitNodes.AddSubMenuItemCheckbox("None", "", status.ExitNodeStatus == nil)
-	onClick(noExitNodeMenu, "")
+	setExitNodeOnClick(noExitNodeMenu, "")
 
 	// Show recommended exit node if available.
 	if status.Self.CapMap.Contains(tailcfg.NodeAttrSuggestExitNodeUI) {
@@ -458,7 +471,7 @@ func (menu *Menu) rebuildExitNodeMenu(ctx context.Context) {
 			}
 			menu.exitNodes.AddSeparator()
 			rm := menu.exitNodes.AddSubMenuItemCheckbox(title, "", false)
-			onClick(rm, sugg.ID)
+			setExitNodeOnClick(rm, sugg.ID)
 			if status.ExitNodeStatus != nil && sugg.ID == status.ExitNodeStatus.ID {
 				rm.Check()
 			}
@@ -490,7 +503,7 @@ func (menu *Menu) rebuildExitNodeMenu(ctx context.Context) {
 			if status.ExitNodeStatus != nil && ps.ID == status.ExitNodeStatus.ID {
 				sm.Check()
 			}
-			onClick(sm, ps.ID)
+			setExitNodeOnClick(sm, ps.ID)
 		}
 	}
 
@@ -510,7 +523,7 @@ func (menu *Menu) rebuildExitNodeMenu(ctx context.Context) {
 
 			// single-city country, no submenu
 			if len(country.cities) == 1 || hideMullvadCities {
-				onClick(countryMenu, country.best.ID)
+				setExitNodeOnClick(countryMenu, country.best.ID)
 				if status.ExitNodeStatus != nil {
 					for _, city := range country.cities {
 						for _, ps := range city.peers {
@@ -527,12 +540,12 @@ func (menu *Menu) rebuildExitNodeMenu(ctx context.Context) {
 			// multi-city country, build submenu with "best available" option and cities.
 			time.Sleep(newMenuDelay)
 			bm := countryMenu.AddSubMenuItemCheckbox("Best Available", "", false)
-			onClick(bm, country.best.ID)
+			setExitNodeOnClick(bm, country.best.ID)
 			countryMenu.AddSeparator()
 
 			for _, city := range country.sortedCities() {
 				cityMenu := countryMenu.AddSubMenuItemCheckbox(city.name, "", false)
-				onClick(cityMenu, city.best.ID)
+				setExitNodeOnClick(cityMenu, city.best.ID)
 				if status.ExitNodeStatus != nil {
 					for _, ps := range city.peers {
 						if status.ExitNodeStatus.ID == ps.ID {
@@ -558,7 +571,7 @@ type mullvadPeers struct {
 func (mp mullvadPeers) sortedCountries() []*mvCountry {
 	countries := slices.Collect(maps.Values(mp.countries))
 	slices.SortFunc(countries, func(a, b *mvCountry) int {
-		return cmp.Compare(a.name, b.name)
+		return stringsx.CompareFold(a.name, b.name)
 	})
 	return countries
 }
@@ -574,7 +587,7 @@ type mvCountry struct {
 func (mc *mvCountry) sortedCities() []*mvCity {
 	cities := slices.Collect(maps.Values(mc.cities))
 	slices.SortFunc(cities, func(a, b *mvCity) int {
-		return cmp.Compare(a.name, b.name)
+		return stringsx.CompareFold(a.name, b.name)
 	})
 	return cities
 }