From 005473a87966f98b41bc1fc54f85cd4b42c93a0b Mon Sep 17 00:00:00 2001
From: Gold872 <thethunder428@gmail.com>
Date: Fri, 29 Sep 2023 17:40:39 -0400
Subject: [PATCH] Prevent multiple instances on linux

---
 linux/my_application.cc | 78 ++++++++++++++++++++++-------------------
 1 file changed, 42 insertions(+), 36 deletions(-)

diff --git a/linux/my_application.cc b/linux/my_application.cc
index ba564781..d62bc019 100644
--- a/linux/my_application.cc
+++ b/linux/my_application.cc
@@ -17,49 +17,56 @@ G_DEFINE_TYPE(MyApplication, my_application, GTK_TYPE_APPLICATION)
 // Implements GApplication::activate.
 static void my_application_activate(GApplication* application) {
   MyApplication* self = MY_APPLICATION(application);
-  GtkWindow* window =
-      GTK_WINDOW(gtk_application_window_new(GTK_APPLICATION(application)));
-
-  // Use a header bar when running in GNOME as this is the common style used
-  // by applications and is the setup most users will be using (e.g. Ubuntu
-  // desktop).
-  // If running on X and not using GNOME then just use a traditional title bar
-  // in case the window manager does more exotic layout, e.g. tiling.
-  // If running on Wayland assume the header bar will work (may need changing
-  // if future cases occur).
-  gboolean use_header_bar = TRUE;
+  GList *list = gtk_application_get_windows(GTK_APPLICATION(application));
+  GtkWindow* existing_window = list ? GTK_WINDOW(list->data) : NULL;
+
+  if (existing_window) {
+    gtk_window_present(existing_window);
+  } else {
+    GtkWindow* window =
+        GTK_WINDOW(gtk_application_window_new(GTK_APPLICATION(application)));
+
+    // Use a header bar when running in GNOME as this is the common style used
+    // by applications and is the setup most users will be using (e.g. Ubuntu
+    // desktop).
+    // If running on X and not using GNOME then just use a traditional title bar
+    // in case the window manager does more exotic layout, e.g. tiling.
+    // If running on Wayland assume the header bar will work (may need changing
+    // if future cases occur).
+    gboolean use_header_bar = TRUE;
 #ifdef GDK_WINDOWING_X11
-  GdkScreen* screen = gtk_window_get_screen(window);
-  if (GDK_IS_X11_SCREEN(screen)) {
-    const gchar* wm_name = gdk_x11_screen_get_window_manager_name(screen);
-    if (g_strcmp0(wm_name, "GNOME Shell") != 0) {
-      use_header_bar = FALSE;
+    GdkScreen* screen = gtk_window_get_screen(window);
+    if (GDK_IS_X11_SCREEN(screen)) {
+      const gchar* wm_name = gdk_x11_screen_get_window_manager_name(screen);
+      if (g_strcmp0(wm_name, "GNOME Shell") != 0) {
+        use_header_bar = FALSE;
+      }
     }
-  }
 #endif
-  if (use_header_bar) {
-    GtkHeaderBar* header_bar = GTK_HEADER_BAR(gtk_header_bar_new());
-    gtk_widget_show(GTK_WIDGET(header_bar));
-    gtk_header_bar_set_title(header_bar, "elastic_dashboard");
-    gtk_header_bar_set_show_close_button(header_bar, TRUE);
-    gtk_window_set_titlebar(window, GTK_WIDGET(header_bar));
-  } else {
-    gtk_window_set_title(window, "elastic_dashboard");
-  }
+    if (use_header_bar) {
+      GtkHeaderBar* header_bar = GTK_HEADER_BAR(gtk_header_bar_new());
+      gtk_widget_show(GTK_WIDGET(header_bar));
+      gtk_header_bar_set_title(header_bar, "elastic_dashboard");
+      gtk_header_bar_set_show_close_button(header_bar, TRUE);
+      gtk_window_set_titlebar(window, GTK_WIDGET(header_bar));
+    } else {
+      gtk_window_set_title(window, "elastic_dashboard");
+    }
 
-  gtk_window_set_default_size(window, 1280, 720);
-  gtk_widget_show(GTK_WIDGET(window));
+    gtk_window_set_default_size(window, 1280, 720);
+    gtk_widget_show(GTK_WIDGET(window));
 
-  g_autoptr(FlDartProject) project = fl_dart_project_new();
-  fl_dart_project_set_dart_entrypoint_arguments(project, self->dart_entrypoint_arguments);
+    g_autoptr(FlDartProject) project = fl_dart_project_new();
+    fl_dart_project_set_dart_entrypoint_arguments(project, self->dart_entrypoint_arguments);
 
-  FlView* view = fl_view_new(project);
-  gtk_widget_show(GTK_WIDGET(view));
-  gtk_container_add(GTK_CONTAINER(window), GTK_WIDGET(view));
+    FlView* view = fl_view_new(project);
+    gtk_widget_show(GTK_WIDGET(view));
+    gtk_container_add(GTK_CONTAINER(window), GTK_WIDGET(view));
 
-  fl_register_plugins(FL_PLUGIN_REGISTRY(view));
+    fl_register_plugins(FL_PLUGIN_REGISTRY(view));
 
-  gtk_widget_grab_focus(GTK_WIDGET(view));
+    gtk_widget_grab_focus(GTK_WIDGET(view));
+  }
 }
 
 // Implements GApplication::local_command_line.
@@ -99,6 +106,5 @@ static void my_application_init(MyApplication* self) {}
 MyApplication* my_application_new() {
   return MY_APPLICATION(g_object_new(my_application_get_type(),
                                      "application-id", APPLICATION_ID,
-                                     "flags", G_APPLICATION_NON_UNIQUE,
                                      nullptr));
 }