Wails UI

client/uiwails/tray_watcher_linux.go

@@ -0,0 +1,148 @@
+//go:build linux && !(linux && 386)
+
+package main
+
+// startStatusNotifierWatcher registers org.kde.StatusNotifierWatcher on the
+// session D-Bus if no other process has already claimed it.
+//
+// Minimal window managers (Fluxbox, OpenBox, i3, etc.) do not ship a
+// StatusNotifier watcher, so tray icons using libayatana-appindicator or
+// the KDE/freedesktop StatusNotifier protocol silently fail.
+//
+// By owning the watcher name in-process we allow the Wails v3 built-in tray
+// to register itself — no external daemon or package needed.
+//
+// When an XEmbed system tray is available (_NET_SYSTEM_TRAY_S0), we also
+// start an in-process XEmbed host that bridges the SNI icon into the
+// XEmbed tray (Fluxbox, IceWM, etc.).
+
+import (
+	"sync"
+
+	"github.com/godbus/dbus/v5"
+	log "github.com/sirupsen/logrus"
+)
+
+const (
+	watcherName  = "org.kde.StatusNotifierWatcher"
+	watcherPath  = "/StatusNotifierWatcher"
+	watcherIface = "org.kde.StatusNotifierWatcher"
+)
+
+type statusNotifierWatcher struct {
+	conn    *dbus.Conn
+	items   []string
+	hosts   map[string]*xembedHost
+	hostsMu sync.Mutex
+}
+
+// RegisterStatusNotifierItem is the D-Bus method called by tray clients.
+// The sender parameter is automatically injected by godbus with the caller's
+// unique bus name (e.g. ":1.42"). It does not appear in the D-Bus signature.
+func (w *statusNotifierWatcher) RegisterStatusNotifierItem(sender dbus.Sender, service string) *dbus.Error {
+	for _, s := range w.items {
+		if s == service {
+			return nil
+		}
+	}
+	w.items = append(w.items, service)
+	log.Debugf("StatusNotifierWatcher: registered item %q from %s", service, sender)
+
+	go w.tryStartXembedHost(string(sender), dbus.ObjectPath(service))
+	return nil
+}
+
+// RegisterStatusNotifierHost is required by the protocol but unused here.
+func (w *statusNotifierWatcher) RegisterStatusNotifierHost(service string) *dbus.Error {
+	log.Debugf("StatusNotifierWatcher: host registered %q", service)
+	return nil
+}
+
+// tryStartXembedHost attempts to create an XEmbed tray icon for the given
+// SNI item. If no XEmbed tray manager is available, this is a no-op.
+func (w *statusNotifierWatcher) tryStartXembedHost(busName string, objPath dbus.ObjectPath) {
+	w.hostsMu.Lock()
+	defer w.hostsMu.Unlock()
+
+	if _, exists := w.hosts[busName]; exists {
+		return
+	}
+
+	// Use a private session bus so our signal subscriptions don't
+	// interfere with Wails' signal handler (which panics on unexpected signals).
+	sessionConn, err := dbus.SessionBusPrivate()
+	if err != nil {
+		log.Debugf("StatusNotifierWatcher: cannot open private session bus for XEmbed host: %v", err)
+		return
+	}
+	if err := sessionConn.Auth(nil); err != nil {
+		log.Debugf("StatusNotifierWatcher: XEmbed host auth failed: %v", err)
+		_ = sessionConn.Close()
+		return
+	}
+	if err := sessionConn.Hello(); err != nil {
+		log.Debugf("StatusNotifierWatcher: XEmbed host Hello failed: %v", err)
+		_ = sessionConn.Close()
+		return
+	}
+
+	host, err := newXembedHost(sessionConn, busName, objPath)
+	if err != nil {
+		log.Debugf("StatusNotifierWatcher: XEmbed host not started: %v", err)
+		return
+	}
+
+	w.hosts[busName] = host
+	go host.run()
+	log.Infof("StatusNotifierWatcher: XEmbed tray icon created for %s", busName)
+}
+
+// startStatusNotifierWatcher claims org.kde.StatusNotifierWatcher on the
+// session bus if it is not already provided by another process.
+// Safe to call unconditionally — it does nothing when a real watcher is present.
+func startStatusNotifierWatcher() {
+	conn, err := dbus.SessionBusPrivate()
+	if err != nil {
+		log.Debugf("StatusNotifierWatcher: cannot open private session bus: %v", err)
+		return
+	}
+	if err := conn.Auth(nil); err != nil {
+		log.Debugf("StatusNotifierWatcher: auth failed: %v", err)
+		_ = conn.Close()
+		return
+	}
+	if err := conn.Hello(); err != nil {
+		log.Debugf("StatusNotifierWatcher: Hello failed: %v", err)
+		_ = conn.Close()
+		return
+	}
+
+	// Check whether another process already owns the watcher name.
+	var owner string
+	callErr := conn.BusObject().Call("org.freedesktop.DBus.GetNameOwner", 0, watcherName).Store(&owner)
+	if callErr == nil && owner != "" {
+		log.Debugf("StatusNotifierWatcher: already owned by %s, skipping", owner)
+		_ = conn.Close()
+		return
+	}
+
+	reply, err := conn.RequestName(watcherName, dbus.NameFlagDoNotQueue)
+	if err != nil || reply != dbus.RequestNameReplyPrimaryOwner {
+		log.Debugf("StatusNotifierWatcher: could not claim name (reply=%v err=%v)", reply, err)
+		_ = conn.Close()
+		return
+	}
+
+	w := &statusNotifierWatcher{
+		conn:  conn,
+		hosts: make(map[string]*xembedHost),
+	}
+	if err := conn.ExportAll(w, dbus.ObjectPath(watcherPath), watcherIface); err != nil {
+		log.Errorf("StatusNotifierWatcher: export failed: %v", err)
+		_ = conn.Close()
+		return
+	}
+
+	log.Infof("StatusNotifierWatcher: active on session bus (enables tray on minimal WMs)")
+	// Connection intentionally kept open for the lifetime of the process.
+}