core/server: add generic dbus service

- Add QML client with subscribe/introspect/getprop/setprop/call
- Add CLI helper `dms notify` that allows async calls with action
  handlers.

core/internal/notify/notify.go

@@ -0,0 +1,170 @@
+package notify
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strconv"
+	"syscall"
+
+	"github.com/godbus/dbus/v5"
+)
+
+const (
+	notifyDest      = "org.freedesktop.Notifications"
+	notifyPath      = "/org/freedesktop/Notifications"
+	notifyInterface = "org.freedesktop.Notifications"
+)
+
+type Notification struct {
+	AppName  string
+	Icon     string
+	Summary  string
+	Body     string
+	FilePath string
+	Timeout  int32
+}
+
+func Send(n Notification) error {
+	conn, err := dbus.SessionBus()
+	if err != nil {
+		return fmt.Errorf("dbus session failed: %w", err)
+	}
+
+	if n.AppName == "" {
+		n.AppName = "DMS"
+	}
+	if n.Timeout == 0 {
+		n.Timeout = 5000
+	}
+
+	var actions []string
+	if n.FilePath != "" {
+		actions = []string{
+			"open", "Open",
+			"folder", "Open Folder",
+		}
+	}
+
+	hints := map[string]dbus.Variant{}
+	if n.FilePath != "" {
+		hints["image_path"] = dbus.MakeVariant(n.FilePath)
+	}
+
+	obj := conn.Object(notifyDest, notifyPath)
+	call := obj.Call(
+		notifyInterface+".Notify",
+		0,
+		n.AppName,
+		uint32(0),
+		n.Icon,
+		n.Summary,
+		n.Body,
+		actions,
+		hints,
+		n.Timeout,
+	)
+
+	if call.Err != nil {
+		return fmt.Errorf("notify call failed: %w", call.Err)
+	}
+
+	var notificationID uint32
+	if err := call.Store(&notificationID); err != nil {
+		return fmt.Errorf("failed to get notification id: %w", err)
+	}
+
+	if len(actions) > 0 && n.FilePath != "" {
+		spawnActionListener(notificationID, n.FilePath)
+	}
+
+	return nil
+}
+
+func spawnActionListener(notificationID uint32, filePath string) {
+	exe, err := os.Executable()
+	if err != nil {
+		return
+	}
+
+	cmd := exec.Command(exe, "notify-action-generic", fmt.Sprintf("%d", notificationID), filePath)
+	cmd.SysProcAttr = &syscall.SysProcAttr{
+		Setsid: true,
+	}
+	cmd.Start()
+}
+
+func RunActionListener(args []string) {
+	if len(args) < 2 {
+		return
+	}
+
+	notificationID, err := strconv.ParseUint(args[0], 10, 32)
+	if err != nil {
+		return
+	}
+
+	filePath := args[1]
+
+	conn, err := dbus.SessionBus()
+	if err != nil {
+		return
+	}
+
+	if err := conn.AddMatchSignal(
+		dbus.WithMatchObjectPath(notifyPath),
+		dbus.WithMatchInterface(notifyInterface),
+	); err != nil {
+		return
+	}
+
+	signals := make(chan *dbus.Signal, 10)
+	conn.Signal(signals)
+
+	for sig := range signals {
+		switch sig.Name {
+		case notifyInterface + ".ActionInvoked":
+			if len(sig.Body) < 2 {
+				continue
+			}
+			id, ok := sig.Body[0].(uint32)
+			if !ok || id != uint32(notificationID) {
+				continue
+			}
+			action, ok := sig.Body[1].(string)
+			if !ok {
+				continue
+			}
+			handleAction(action, filePath)
+			return
+
+		case notifyInterface + ".NotificationClosed":
+			if len(sig.Body) < 1 {
+				continue
+			}
+			id, ok := sig.Body[0].(uint32)
+			if !ok || id != uint32(notificationID) {
+				continue
+			}
+			return
+		}
+	}
+}
+
+func handleAction(action, filePath string) {
+	switch action {
+	case "open", "default":
+		openPath(filePath)
+	case "folder":
+		openPath(filepath.Dir(filePath))
+	}
+}
+
+func openPath(path string) {
+	cmd := exec.Command("xdg-open", path)
+	cmd.SysProcAttr = &syscall.SysProcAttr{
+		Setsid: true,
+	}
+	cmd.Start()
+}