[client][linux] Use DBus to ensure single instance

client/lib/ui/app/app.dart

@@ -1,3 +1,6 @@
+import 'dart:io';
+
+import 'package:dbus/dbus.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_state_notifier/flutter_state_notifier.dart';
@@ -24,6 +27,40 @@ class _PhylumAppState extends State<PhylumApp> {
   final PhylumRouterDelegate routerDelegate = PhylumRouterDelegate(builder: (context) => const AccountSelector());
   final AccountManager<PhylumAccount> accountManager = createAccountManager(isPrimary());
 
+  @override
+  void initState() {
+    super.initState();
+    if (defaultTargetPlatform == TargetPlatform.linux) {
+      startDBusClient();
+    }
+  }
+
+  void startDBusClient() async {
+    final sessionClient = DBusClient.session();
+    final requestReply =
+        await sessionClient.requestName('cloud.phylum.drive.Instance', flags: {DBusRequestNameFlag.doNotQueue});
+    if (requestReply == DBusRequestNameReply.primaryOwner) {
+      await sessionClient.registerObject(InstanceObject());
+    } else if (requestReply == DBusRequestNameReply.exists) {
+      print('Instance Already Running');
+      final object = DBusRemoteObject(
+        sessionClient,
+        name: 'cloud.phylum.drive.Instance',
+        path: DBusObjectPath('/drive/phylum/cloud/Instance/Object'),
+      );
+
+      var value = await object.getProperty('cloud.phylum.drive.Instance', 'Version', signature: DBusSignature('s'));
+      var version = value.asString();
+      print('Version $version');
+
+      await object.callMethod('cloud.phylum.drive.Instance', 'Show', [], replySignature: DBusSignature(''));
+      await sessionClient.close();
+      exit(0);
+    } else {
+      throw StateError('Unsupported DBus Name Request Reply: $requestReply');
+    }
+  }
+
   @override
   Widget build(BuildContext context) {
     return MultiProvider(
@@ -64,3 +101,36 @@ class _PhylumAppState extends State<PhylumApp> {
         });
   }
 }
+
+class InstanceObject extends DBusObject {
+  InstanceObject() : super(DBusObjectPath('/drive/phylum/cloud/Instance/Object'));
+
+  @override
+  Future<DBusMethodResponse> getProperty(String interface, String name) async {
+    if (interface == 'cloud.phylum.drive.Instance') {
+      if (name == 'Version') {
+        return DBusGetPropertyResponse(DBusString('0.7'));
+      } else {
+        return DBusMethodErrorResponse.unknownProperty();
+      }
+    } else {
+      return DBusMethodErrorResponse.unknownInterface();
+    }
+  }
+
+  @override
+  Future<DBusMethodResponse> handleMethodCall(DBusMethodCall methodCall) async {
+    if (methodCall.interface == 'cloud.phylum.drive.Instance') {
+      if (methodCall.name == 'Show') {
+        if (methodCall.signature != DBusSignature('')) {
+          return DBusMethodErrorResponse.invalidArgs();
+        }
+        return DBusMethodSuccessResponse([]);
+      } else {
+        return DBusMethodErrorResponse.unknownMethod();
+      }
+    } else {
+      return DBusMethodErrorResponse.unknownInterface();
+    }
+  }
+}

client/pubspec.lock

@@ -226,7 +226,7 @@ packages:
     source: hosted
     version: "3.1.3"
   dbus:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: dbus
       sha256: "79e0c23480ff85dc68de79e2cd6334add97e48f7f4865d17686dd6ea81a47e8c"

client/pubspec.yaml

@@ -15,6 +15,7 @@ dependencies:
   cached_network_image_platform_interface:
   circular_profile_avatar:
   collection:
+  dbus:
   device_info_plus: ^11.5.0
   drift: ^2.19.1+1
   drift_flutter: ^0.2.1