Implement SystemD activation

Closes #369
Closes #433

Author: amezin

Makefile

@@ -192,6 +192,7 @@ PACK_CONTENT += \
 	ddterm/com.github.amezin.ddterm.Extension.xml \
 	ddterm/com.github.amezin.ddterm.desktop.in \
 	ddterm/com.github.amezin.ddterm.service.in \
+	ddterm/dbus-com.github.amezin.ddterm.service.in \
 	LICENSE \
 
 PACK_CONTENT := $(sort $(PACK_CONTENT))

ddterm/app/application.js

@@ -19,6 +19,7 @@
 
 'use strict';
 
+const ByteArray = imports.byteArray;
 const System = imports.system;
 
 const Me = imports.misc.extensionUtils.getCurrentExtension();
@@ -83,6 +84,14 @@ const Application = GObject.registerClass(
                 'Ask the extension to launch the app',
                 null
             );
+            this.add_main_option(
+                'attach-unit',
+                0,
+                GLib.OptionFlags.NONE,
+                GLib.OptionArg.STRING,
+                'Attach launched application process to the specified systemd unit',
+                'UNIT_NAME'
+            );
 
             this.connect('startup', this.startup.bind(this));
             this.connect('handle-local-options', this.handle_local_options.bind(this));
@@ -230,8 +239,7 @@ const Application = GObject.registerClass(
         handle_local_options(_, options) {
             if (options.lookup('launch-through-extension')) {
                 try {
-                    const iface = extensiondbus.get();
-                    iface.ServiceSync();
+                    this.launch_through_extension(options);
                     return 0;
                 } catch (e) {
                     logError(e);
@@ -247,6 +255,56 @@ const Application = GObject.registerClass(
             return -1;
         }
 
+        launch_through_extension(options) {
+            const iface = extensiondbus.get();
+            const [pid] = iface.ServiceSync();
+
+            const attach_unit = options.lookup('attach-unit', 's');
+            if (attach_unit) {
+                Gio.DBus.session.call_sync(
+                    'org.freedesktop.systemd1',
+                    '/org/freedesktop/systemd1',
+                    'org.freedesktop.systemd1.Manager',
+                    'AttachProcessesToUnit',
+                    GLib.Variant.new_tuple([
+                        GLib.Variant.new_string(attach_unit),
+                        GLib.Variant.new_string(''),
+                        GLib.Variant.new_array(
+                            new GLib.VariantType('u'),
+                            [GLib.Variant.new_uint32(parseInt(pid, 10))]
+                        ),
+                    ]),
+                    null,
+                    Gio.DBusCallFlags.NONE,
+                    -1,
+                    null
+                );
+            }
+
+            const notify_socket_path = GLib.getenv('NOTIFY_SOCKET');
+            if (notify_socket_path) {
+                const abstract = notify_socket_path.startsWith('@');
+
+                const address = new Gio.UnixSocketAddress({
+                    path: abstract ? notify_socket_path.substr(1) : notify_socket_path,
+                    abstract,
+                });
+
+                const socket = Gio.Socket.new(
+                    Gio.SocketFamily.UNIX,
+                    Gio.SocketType.DATAGRAM,
+                    Gio.SocketProtocol.DEFAULT
+                );
+
+                try {
+                    socket.connect(address, null);
+                    socket.send(ByteArray.fromString(`MAINPID=${pid}`), null);
+                } finally {
+                    socket.close();
+                }
+            }
+        }
+
         preferences() {
             if (this.prefs_dialog === null) {
                 this.prefs_dialog = new PrefsDialog({

ddterm/com.github.amezin.ddterm.Extension.xml

@@ -5,7 +5,9 @@
     <interface name="com.github.amezin.ddterm.Extension">
         <method name="Toggle"/>
         <method name="Activate"/>
-        <method name="Service"/>
+        <method name="Service">
+            <arg type="s" name="pid" direction="out"/>
+        </method>
         <method name="GetTargetRect">
             <arg type="i" name="x" direction="out"/>
             <arg type="i" name="y" direction="out"/>

ddterm/com.github.amezin.ddterm.service.in

@@ -1,3 +1,4 @@
 [D-BUS Service]
 Name=com.github.amezin.ddterm
 Exec="@LAUNCHER@" --launch-through-extension
+SystemdService=dbus-com.github.amezin.ddterm.service

ddterm/dbus-com.github.amezin.ddterm.service.in

@@ -0,0 +1,6 @@
+[Service]
+Type=dbus
+BusName=com.github.amezin.ddterm
+ExecStart="@LAUNCHER@" --launch-through-extension --attach-unit %n
+Delegate=
+NotifyAccess=main

ddterm/shell/extension.js

@@ -44,6 +44,7 @@ let window_connections = null;
 let dbus_interface = null;
 
 let desktop_entry = null;
+let systemd_service = null;
 let dbus_service = null;
 
 const APP_ID = 'com.github.amezin.ddterm';
@@ -128,7 +129,7 @@ class ExtensionDBusInterface {
     }
 
     Service() {
-        spawn_app();
+        return spawn_app();
     }
 
     GetTargetRect() {
@@ -266,6 +267,31 @@ function enable() {
     );
     desktop_entry.install();
 
+    systemd_service = new InstallableResource(
+        Me.dir.get_child('ddterm').get_child('dbus-com.github.amezin.ddterm.service.in'),
+        Gio.File.new_for_path(GLib.build_filenamev(
+            [
+                GLib.get_user_runtime_dir(),
+                'systemd',
+                'user',
+                `dbus-${APP_ID}.service`,
+            ]))
+    );
+    systemd_service.install();
+
+    Gio.DBus.session.call(
+        'org.freedesktop.systemd1',
+        '/org/freedesktop/systemd1',
+        'org.freedesktop.systemd1.Manager',
+        'Reload',
+        null,
+        null,
+        Gio.DBusCallFlags.NO_AUTO_START,
+        -1,
+        null,
+        null
+    );
+
     dbus_service = new InstallableResource(
         Me.dir.get_child('ddterm').get_child('com.github.amezin.ddterm.service.in'),
         Gio.File.new_for_path(GLib.build_filenamev(
@@ -346,6 +372,11 @@ function disable() {
         desktop_entry = null;
     }
 
+    if (systemd_service) {
+        systemd_service.uninstall();
+        systemd_service = null;
+    }
+
     if (dbus_service) {
         dbus_service.uninstall();
         dbus_service = null;
@@ -356,7 +387,7 @@ function disable() {
 
 function spawn_app() {
     if (subprocess)
-        return;
+        return subprocess.get_identifier();
 
     const subprocess_launcher = Gio.SubprocessLauncher.new(Gio.SubprocessFlags.NONE);
 
@@ -387,6 +418,8 @@ function spawn_app() {
         subprocess = subprocess_launcher.spawnv(argv);
 
     subprocess.wait_async(null, subprocess_terminated);
+
+    return subprocess.get_identifier();
 }
 
 function subprocess_terminated(source) {