From 91156d295c9a24d5d2d2f7072e10fb481401eff7 Mon Sep 17 00:00:00 2001
From: Timon <me@timon.zip>
Date: Fri, 25 Jul 2025 21:38:54 +0000
Subject: [PATCH] Desktop: Handle another instance is already running (#2938)

Handle another instance is already running
---
 desktop/src/cef/context.rs                          | 12 +++++++++---
 desktop/src/cef/internal/browser_process_handler.rs |  4 ++++
 desktop/src/main.rs                                 |  8 ++++++--
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/desktop/src/cef/context.rs b/desktop/src/cef/context.rs
index 04ebffb4..a26aa933 100644
--- a/desktop/src/cef/context.rs
+++ b/desktop/src/cef/context.rs
@@ -1,4 +1,4 @@
-use cef::sys::CEF_API_VERSION_LAST;
+use cef::sys::{CEF_API_VERSION_LAST, cef_resultcode_t};
 use cef::{App, BrowserSettings, Client, DictionaryValue, ImplBrowser, ImplBrowserHost, ImplCommandLine, RenderHandler, RequestContext, WindowInfo, browser_host_create_browser_sync, initialize};
 use cef::{Browser, CefString, Settings, api_hash, args::Args, execute_process};
 use thiserror::Error;
@@ -74,7 +74,11 @@ impl Context<Setup> {
 
 		let result = initialize(Some(self.args.as_main_args()), Some(&settings), Some(&mut cef_app), std::ptr::null_mut());
 		if result != 1 {
-			return Err(InitError::InitializationFailed);
+			let cef_exit_code = cef::get_exit_code() as u32;
+			if cef_exit_code == cef_resultcode_t::CEF_RESULT_CODE_NORMAL_EXIT_PROCESS_NOTIFIED as u32 {
+				return Err(InitError::AlreadyRunning);
+			}
+			return Err(InitError::InitializationFailed(cef_exit_code));
 		}
 
 		let render_handler = RenderHandlerImpl::new(event_handler.clone());
@@ -146,5 +150,7 @@ pub(crate) enum SetupError {
 #[derive(Error, Debug)]
 pub(crate) enum InitError {
 	#[error("initialization failed")]
-	InitializationFailed,
+	InitializationFailed(u32),
+	#[error("Another instance is already running")]
+	AlreadyRunning,
 }
diff --git a/desktop/src/cef/internal/browser_process_handler.rs b/desktop/src/cef/internal/browser_process_handler.rs
index 5179dd3b..4edacc5c 100644
--- a/desktop/src/cef/internal/browser_process_handler.rs
+++ b/desktop/src/cef/internal/browser_process_handler.rs
@@ -29,6 +29,10 @@ impl<H: CefEventHandler + Clone> ImplBrowserProcessHandler for BrowserProcessHan
 		self.event_handler.schedule_cef_message_loop_work(Instant::now() + Duration::from_millis(delay_ms as u64));
 	}
 
+	fn on_already_running_app_relaunch(&self, _command_line: Option<&mut cef::CommandLine>, _current_directory: Option<&CefString>) -> ::std::os::raw::c_int {
+		1 // Return 1 to prevent default behavior of opening a empty browser window
+	}
+
 	fn get_raw(&self) -> *mut _cef_browser_process_handler_t {
 		self.object.cast()
 	}
diff --git a/desktop/src/main.rs b/desktop/src/main.rs
index c53848f8..6ce35179 100644
--- a/desktop/src/main.rs
+++ b/desktop/src/main.rs
@@ -41,8 +41,12 @@ fn main() {
 	let wgpu_context = futures::executor::block_on(WgpuContext::new());
 	let cef_context = match cef_context.init(cef::CefHandler::new(window_size_receiver, event_loop.create_proxy(), wgpu_context.clone())) {
 		Ok(c) => c,
-		Err(cef::InitError::InitializationFailed) => {
-			tracing::error!("Cef initialization failed");
+		Err(cef::InitError::AlreadyRunning) => {
+			tracing::error!("Another instance is already running, Exiting.");
+			exit(0);
+		}
+		Err(cef::InitError::InitializationFailed(code)) => {
+			tracing::error!("Cef initialization failed with code: {code}");
 			exit(1);
 		}
 	};