Port IPC to Rust, delete the app folder finally! There's still one weird quirk with the window restoration behavior.

Author: trypsynth

app/app.cpp

@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: paperback 0.8.0\n"
 "Report-Msgid-Bugs-To: https://github.com/trypsynth/paperback/issues\n"
-"POT-Creation-Date: 2026-01-31 11:48-0700\n"
+"POT-Creation-Date: 2026-02-05 17:28-0700\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -17,6 +17,14 @@ msgstr ""
 "Content-Type: text/plain; charset=CHARSET\n"
 "Content-Transfer-Encoding: 8bit\n"
 
+#: C:\Users\Quin\git\paperback\src\ui\app.rs
+msgid "Failed to create IPC server"
+msgstr ""
+
+#: C:\Users\Quin\git\paperback\src\ui\app.rs
+msgid "Warning"
+msgstr ""
+
 #: C:\Users\Quin\git\paperback\src\ui\dialogs.rs
 #: C:\Users\Quin\git\paperback\src\ui\find.rs
 msgid "Options"

app/app.hpp

@@ -0,0 +1,38 @@
+use std::{env, path::{Path, PathBuf}};
+
+pub const IPC_SERVICE: &str = "4242";
+pub const IPC_TOPIC_OPEN_FILE: &str = "open_file";
+pub const IPC_COMMAND_ACTIVATE: &str = "ACTIVATE";
+pub const IPC_HOST_LOCALHOST: &str = "localhost";
+pub const SINGLE_INSTANCE_NAME: &str = "paperback_running";
+
+#[derive(Debug, Clone)]
+pub enum IpcCommand {
+	Activate,
+	OpenFile(PathBuf),
+}
+
+pub fn decode_execute_payload(data: &[u8]) -> Option<IpcCommand> {
+	if data.is_empty() {
+		return None;
+	}
+	let payload = String::from_utf8_lossy(data);
+	let payload = payload.trim_end_matches('\0');
+	if payload.is_empty() {
+		return None;
+	}
+	if payload == IPC_COMMAND_ACTIVATE {
+		return Some(IpcCommand::Activate);
+	}
+	Some(IpcCommand::OpenFile(PathBuf::from(payload)))
+}
+
+pub fn normalize_cli_path(path: &Path) -> PathBuf {
+	if let Ok(normalized) = path.canonicalize() {
+		return normalized;
+	}
+	if path.is_absolute() {
+		return path.to_path_buf();
+	}
+	env::current_dir().map_or_else(|_| path.to_path_buf(), |cwd| cwd.join(path))
+}

po/paperback.pot

@@ -4,6 +4,7 @@
 mod config;
 mod document;
 mod html_to_text;
+mod ipc;
 mod parser;
 mod reader_core;
 mod session;

src/ipc.rs

@@ -1,20 +1,35 @@
 use std::{
 	env,
-	path::{Path, PathBuf},
+	path::Path,
+	process,
 	rc::Rc,
-	sync::Mutex,
+	sync::{
+		Mutex,
+		atomic::{AtomicUsize, Ordering},
+	},
 };
 
-use wxdragon::prelude::*;
+use wxdragon::{prelude::*, translations::translate as t};
 
 use super::MainWindow;
-use crate::{config::ConfigManager, translation_manager::TranslationManager};
+use crate::{
+	config::ConfigManager,
+	ipc::{
+		IPC_COMMAND_ACTIVATE, IPC_HOST_LOCALHOST, IPC_SERVICE, IPC_TOPIC_OPEN_FILE, IpcCommand, SINGLE_INSTANCE_NAME,
+		decode_execute_payload, normalize_cli_path,
+	},
+	translation_manager::TranslationManager,
+};
 
 pub struct PaperbackApp {
 	_config: Rc<Mutex<ConfigManager>>,
-	_main_window: MainWindow,
+	_main_window: Rc<MainWindow>,
+	_ipc_server: Option<IPCServer>,
+	_single_instance_checker: Option<SingleInstanceChecker>,
 }
 
+static MAIN_WINDOW_PTR: AtomicUsize = AtomicUsize::new(0);
+
 impl PaperbackApp {
 	pub fn new(_app: App) -> Self {
 		let mut config = ConfigManager::new();
@@ -28,14 +43,28 @@ impl PaperbackApp {
 			}
 		}
 		let config = Rc::new(Mutex::new(config));
-		let main_window = MainWindow::new(Rc::clone(&config));
+		let single_instance_checker = SingleInstanceChecker::new(SINGLE_INSTANCE_NAME, None);
+		if let Some(checker) = single_instance_checker.as_ref() {
+			if checker.is_another_running() {
+				send_ipc_command(ipc_command_from_cli());
+				process::exit(0);
+			}
+		}
+		let main_window = Rc::new(MainWindow::new(Rc::clone(&config)));
+		MAIN_WINDOW_PTR.store(Rc::as_ptr(&main_window) as usize, Ordering::SeqCst);
 		wxdragon::app::set_top_window(main_window.frame());
+		let ipc_server = start_ipc_server(Rc::clone(&main_window));
 		main_window.show();
 		open_from_command_line(&main_window);
 		if config.lock().unwrap().get_app_bool("check_for_updates_on_startup", true) {
 			MainWindow::check_for_updates(true);
 		}
-		Self { _config: config, _main_window: main_window }
+		Self {
+			_config: config,
+			_main_window: main_window,
+			_ipc_server: ipc_server,
+			_single_instance_checker: single_instance_checker,
+		}
 	}
 }
 
@@ -46,12 +75,63 @@ fn open_from_command_line(main_window: &MainWindow) {
 	}
 }
 
-fn normalize_cli_path(path: &Path) -> PathBuf {
-	if let Ok(normalized) = path.canonicalize() {
-		return normalized;
+fn main_window_from_ptr() -> Option<&'static MainWindow> {
+	let ptr = MAIN_WINDOW_PTR.load(Ordering::SeqCst);
+	if ptr == 0 {
+		return None;
 	}
-	if path.is_absolute() {
-		return path.to_path_buf();
+	unsafe { (ptr as *const MainWindow).as_ref() }
+}
+
+fn ipc_command_from_cli() -> IpcCommand {
+	if let Some(path) = env::args().nth(1) {
+		let normalized = normalize_cli_path(Path::new(&path));
+		return IpcCommand::OpenFile(normalized);
+	}
+	IpcCommand::Activate
+}
+
+fn send_ipc_command(command: IpcCommand) {
+	let client = IPCClient::new();
+	let Some(conn) = client.make_connection(IPC_HOST_LOCALHOST, IPC_SERVICE, IPC_TOPIC_OPEN_FILE) else {
+		return;
+	};
+	let payload = match command {
+		IpcCommand::Activate => IPC_COMMAND_ACTIVATE.to_string(),
+		IpcCommand::OpenFile(path) => path.to_string_lossy().to_string(),
+	};
+	let _ = conn.execute_string(&payload);
+	let _ = conn.disconnect();
+}
+
+fn start_ipc_server(main_window: Rc<MainWindow>) -> Option<IPCServer> {
+	let server = IPCServer::new(move |topic| {
+		if topic != IPC_TOPIC_OPEN_FILE {
+			return None;
+		}
+		Some(
+			IPCConnection::builder()
+				.on_execute({
+					move |_topic, data, _format| {
+						let Some(command) = decode_execute_payload(data) else {
+							return false;
+						};
+						wxdragon::call_after(Box::new(move || {
+							if let Some(window) = main_window_from_ptr() {
+								window.handle_ipc_command(command);
+							}
+						}));
+						true
+					}
+				})
+				.build(),
+		)
+	});
+	if !server.create(IPC_SERVICE) {
+		let dialog = MessageDialog::builder(main_window.frame(), &t("Failed to create IPC server"), &t("Warning"))
+			.with_style(MessageDialogStyle::OK | MessageDialogStyle::IconWarning | MessageDialogStyle::Centre)
+			.build();
+		dialog.show_modal();
 	}
-	env::current_dir().map_or_else(|_| path.to_path_buf(), |cwd| cwd.join(path))
+	Some(server)
 }