Start work on Linux desktop portal kitten

go.mod

@@ -10,6 +10,7 @@ require (
 	github.com/bmatcuk/doublestar/v4 v4.8.1
 	github.com/dlclark/regexp2 v1.11.5
 	github.com/edwvee/exiffix v0.0.0-20240229113213-0dbb146775be
+	github.com/godbus/dbus/v5 v5.1.0
 	github.com/google/go-cmp v0.7.0
 	github.com/google/uuid v1.6.0
 	github.com/kovidgoyal/imaging v1.6.4

go.sum

@@ -18,6 +18,8 @@ github.com/edwvee/exiffix v0.0.0-20240229113213-0dbb146775be h1:FNPYI8/ifKGW7kdB
 github.com/edwvee/exiffix v0.0.0-20240229113213-0dbb146775be/go.mod h1:G3dK5MziX9e4jUa8PWjowCOPCcyQwxsZ5a0oYA73280=
 github.com/go-ole/go-ole v1.2.6 h1:/Fpf6oFPoeFik9ty7siob0G6Ke8QvQEuVcuChpwXzpY=
 github.com/go-ole/go-ole v1.2.6/go.mod h1:pprOEPIfldk/42T2oK7lQ4v4JSDwmV0As9GaiUsvbm0=
+github.com/godbus/dbus/v5 v5.1.0 h1:4KLkAxT3aOY8Li4FRJe/KvhoNFFxo0m6fNuFUO8QJUk=
+github.com/godbus/dbus/v5 v5.1.0/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
 github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
 github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=

kittens/desktop_ui/main.go

@@ -0,0 +1,54 @@
+package desktop_ui
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/kovidgoyal/kitty/tools/cli"
+	"github.com/kovidgoyal/kitty/tools/utils"
+)
+
+var _ = fmt.Print
+
+type Options struct {
+	Color_scheme string
+}
+
+func run_server(opts *Options) (err error) {
+	portal := NewPortal(opts)
+	ctx := context.Background()
+	err = portal.Start(ctx)
+	// Run until explicitly stopped.
+	<-ctx.Done()
+	return
+}
+
+func EntryPoint(root *cli.Command) {
+	parent := root.AddSubCommand(&cli.Command{
+		Name:             "desktop-ui",
+		ShortDescription: "Implement various desktop components for use with lightweight compositors/window managers on Linux",
+		Run: func(cmd *cli.Command, args []string) (int, error) {
+			cmd.ShowHelp()
+			return 1, nil
+		},
+	})
+	rs := parent.AddSubCommand(&cli.Command{
+		Name:             "run-server",
+		ShortDescription: "Start the various servers used to integrate with the Linux desktop",
+		HelpText:         "This should be run very early in the startup sequence of your window manager, before any other programs are run.",
+		Run: func(cmd *cli.Command, args []string) (rc int, err error) {
+			opts := Options{}
+			err = cmd.GetOptionValues(&opts)
+			if err == nil {
+				err = run_server(&opts)
+			}
+			return utils.IfElse(err == nil, 0, 1), err
+		},
+	})
+	rs.Add(cli.OptionSpec{
+		Name: `--color-scheme`, Type: "choices", Dest: `Color_scheme`, Choices: "no-preference, light, dark",
+		Completer: cli.NamesCompleter("Choices for color-scheme", "no-preference", "light", "dark"),
+		Help:      "The color scheme for your system. This sets the initial value of the color scheme. It can be changed subsequently by using the color-scheme sub-command.",
+	})
+
+}

kittens/desktop_ui/main.py

@@ -0,0 +1,4 @@
+#!/usr/bin/env python
+# License: GPLv3 Copyright: 2025, Kovid Goyal <kovid at kovidgoyal.net>
+
+

kittens/desktop_ui/portal.go

@@ -0,0 +1,228 @@
+package desktop_ui
+
+import (
+	"context"
+	"fmt"
+	"os"
+
+	"github.com/godbus/dbus/v5"
+	"github.com/godbus/dbus/v5/introspect"
+	"github.com/godbus/dbus/v5/prop"
+)
+
+var _ = fmt.Print
+
+const PORTAL_COLOR_SCHEME_NAMESPACE = "org.freedesktop.appearance"
+const PORTAL_COLOR_SCHEME_KEY = "color-scheme"
+const PORTAL_BUS_NAME = "org.freedesktop.impl.portal.desktop.kitty"
+const PORTAL_OBJ_PATH = "/org/freedesktop/portal/desktop"
+
+const SETTINGS_INTERFACE = "org.freedesktop.impl.portal.Settings"
+
+// Special portal setting used to check if darkman is in used by the portal.
+const SETTINGS_CANARY_NAMESPACE = "net.kovidgoyal.kitty"
+const SETTINGS_CANARY_KEY = "status"
+
+type ColorScheme uint
+
+const (
+	NO_PREFERENCE ColorScheme = iota
+	DARK
+	LIGHT
+)
+
+type Portal struct {
+	Color_scheme ColorScheme
+	bus          *dbus.Conn
+}
+
+func NewPortal(opts *Options) *Portal {
+	ans := Portal{}
+	switch opts.Color_scheme {
+	case "dark":
+		ans.Color_scheme = DARK
+	case "light":
+		ans.Color_scheme = LIGHT
+	default:
+		ans.Color_scheme = NO_PREFERENCE
+	}
+	return &ans
+}
+
+func (self *Portal) Start(ctx context.Context) (err error) {
+	dbus_opts := dbus.WithContext(ctx)
+	if self.bus, err = dbus.ConnectSessionBus(dbus_opts); err != nil {
+		return fmt.Errorf("could not connect to session D-Bus: %s", err)
+	}
+
+	// Define the "Version" prop (its value will be static).
+	propsSpec := map[string]map[string]*prop.Prop{
+		SETTINGS_INTERFACE: {
+			"Version": {
+				Value:    1,
+				Writable: false,
+				Emit:     prop.EmitTrue,
+			},
+		},
+	}
+	// Export the "Version" prop.
+	versionProp, err := prop.Export(self.bus, PORTAL_OBJ_PATH, propsSpec)
+	if err != nil {
+		return fmt.Errorf("failed to export D-Bus prop: %v", err)
+	}
+
+	// Exoprt the D-Bus object.
+	if err = self.bus.Export(self.bus, PORTAL_OBJ_PATH, SETTINGS_INTERFACE); err != nil {
+		return fmt.Errorf("failed to export interface: %v", err)
+	}
+
+	// Declare change signal
+	settingChanged := introspect.Signal{
+		Name: "SettingChanged",
+		Args: []introspect.Arg{
+			{
+				Name: "namespace",
+				Type: "s",
+			},
+			{
+				Name: "key",
+				Type: "s",
+			},
+			{
+				Name: "value",
+				Type: "v",
+			},
+		},
+	}
+
+	readMethod := introspect.Method{
+		Name: "Read",
+		Args: []introspect.Arg{
+			{
+				Name:      "namespace",
+				Type:      "s",
+				Direction: "in",
+			},
+			{
+				Name:      "key",
+				Type:      "s",
+				Direction: "in",
+			},
+			{
+				Name:      "value",
+				Type:      "v",
+				Direction: "out",
+			},
+		},
+	}
+	readAllMethod := introspect.Method{
+		Name: "ReadAll",
+		Args: []introspect.Arg{
+			{
+				Name:      "namespaces",
+				Type:      "as",
+				Direction: "in",
+			},
+			{
+				Name:      "value",
+				Type:      "a{sa{sv}}",
+				Direction: "out",
+			},
+		},
+	}
+
+	portalInterface := introspect.Interface{
+		Name:       SETTINGS_INTERFACE,
+		Signals:    []introspect.Signal{settingChanged},
+		Properties: versionProp.Introspection(SETTINGS_INTERFACE),
+		Methods:    []introspect.Method{readMethod, readAllMethod},
+	}
+
+	n := &introspect.Node{
+		Name: PORTAL_OBJ_PATH,
+		Interfaces: []introspect.Interface{
+			introspect.IntrospectData,
+			prop.IntrospectData,
+			portalInterface,
+		},
+	}
+
+	if err = self.bus.Export(
+		introspect.NewIntrospectable(n),
+		PORTAL_OBJ_PATH,
+		"org.freedesktop.DBus.Introspectable",
+	); err != nil {
+		return fmt.Errorf("failed to export dbus name: %v", err)
+	}
+
+	reply, err := self.bus.RequestName(PORTAL_BUS_NAME, dbus.NameFlagDoNotQueue)
+	if err != nil {
+		return fmt.Errorf("failed to register dbus name: %v", err)
+	}
+	if reply != dbus.RequestNameReplyPrimaryOwner {
+		return fmt.Errorf("can't register D-Bus name: name already taken")
+	}
+
+	return
+}
+
+func (self *Portal) ChangeMode(x string) (err error) {
+	if self.bus == nil {
+		return fmt.Errorf("cannot emit portal signal; no connection to dbus")
+	}
+	switch x {
+	case "toggle":
+		switch self.Color_scheme {
+		case LIGHT:
+			self.Color_scheme = DARK
+		case DARK:
+			self.Color_scheme = LIGHT
+		}
+	case "light":
+		self.Color_scheme = LIGHT
+	case "dark":
+		self.Color_scheme = DARK
+	case "no-preference":
+		self.Color_scheme = NO_PREFERENCE
+	default:
+		return fmt.Errorf("%s is not a valid value for color-scheme. Valid values are: light, dark, no-preference and toggle", x)
+	}
+
+	if err = self.bus.Emit(
+		PORTAL_OBJ_PATH,
+		SETTINGS_INTERFACE+".SettingChanged",
+		PORTAL_COLOR_SCHEME_NAMESPACE,
+		PORTAL_COLOR_SCHEME_KEY,
+		dbus.MakeVariant(self.Color_scheme),
+	); err != nil {
+		fmt.Fprintf(os.Stderr, "Couldn't emit signal: %s", err)
+		err = nil
+	}
+	return
+}
+
+func (self *Portal) Read(namespace string, key string) (dbus.Variant, *dbus.Error) {
+	if namespace == PORTAL_COLOR_SCHEME_NAMESPACE && key == PORTAL_COLOR_SCHEME_KEY {
+		return dbus.MakeVariant(self.Color_scheme), nil
+	}
+	if namespace == SETTINGS_CANARY_NAMESPACE && key == SETTINGS_CANARY_KEY {
+		return dbus.MakeVariant("running"), nil
+	}
+	return dbus.Variant{}, dbus.NewError("org.freedesktop.portal.Error.NotFound", []any{fmt.Sprintf("the setting %s in the namespace %s is not supported", key, namespace)})
+}
+
+func (self *Portal) ReadAll(namespaces []string) (map[string]map[string]dbus.Variant, *dbus.Error) {
+	values := map[string]map[string]dbus.Variant{}
+	for _, namespace := range namespaces {
+		if namespace == PORTAL_COLOR_SCHEME_NAMESPACE {
+			values[PORTAL_COLOR_SCHEME_NAMESPACE] = map[string]dbus.Variant{
+				PORTAL_COLOR_SCHEME_KEY: dbus.MakeVariant(self.Color_scheme),
+			}
+		} else if namespace == SETTINGS_CANARY_NAMESPACE {
+			values[SETTINGS_CANARY_NAMESPACE] = map[string]dbus.Variant{
+				SETTINGS_CANARY_KEY: dbus.MakeVariant("running"),
+			}
+		}
+	}
+	return values, nil
+}

tools/cmd/tool/main.go

@@ -8,6 +8,7 @@ import (
 	"github.com/kovidgoyal/kitty/kittens/ask"
 	"github.com/kovidgoyal/kitty/kittens/choose_fonts"
 	"github.com/kovidgoyal/kitty/kittens/clipboard"
+	"github.com/kovidgoyal/kitty/kittens/desktop_ui"
 	"github.com/kovidgoyal/kitty/kittens/diff"
 	"github.com/kovidgoyal/kitty/kittens/hints"
 	"github.com/kovidgoyal/kitty/kittens/hyperlinked_grep"
@@ -63,6 +64,8 @@ func KittyToolEntryPoints(root *cli.Command) {
 	unicode_input.EntryPoint(root)
 	// show_key
 	show_key.EntryPoint(root)
+	// desktop_ui
+	desktop_ui.EntryPoint(root)
 	// mouse_demo
 	root.AddSubCommand(&cli.Command{
 		Name:             "mouse-demo",