Desktop: Limit application to a single instance (#3441)

* only allow single instance

* more reliable CEF cache cleanup

* some cleanup

* fix lock file location

* add simple signal handling

* fix skew handles on desktop

* mac remove unused helpers

Author: timon-schelling

Cargo.lock

@@ -43,6 +43,8 @@ open = { workspace = true }
 rand = { workspace = true, features = ["thread_rng"] }
 serde = { workspace = true }
 clap = { workspace = true, features = ["derive"] }
+pidlock = "0.2.2"
+ctrlc = "3.5.1"
 
 # Windows-specific dependencies
 [target.'cfg(target_os = "windows")'.dependencies]

desktop/Cargo.toml

@@ -40,7 +40,7 @@ fn bundle(out_dir: &Path, app_bin: &Path, helper_bin: &Path) -> PathBuf {
 
 	create_app(&app_dir, APP_ID, APP_NAME, app_bin, false);
 
-	for helper_type in [None, Some("GPU"), Some("Renderer"), Some("Plugin"), Some("Alerts")] {
+	for helper_type in [None, Some("GPU"), Some("Renderer")] {
 		let helper_id_suffix = helper_type.map(|t| format!(".{t}")).unwrap_or_default();
 		let helper_id = format!("{APP_ID}.helper{helper_id_suffix}");
 		let helper_name_suffix = helper_type.map(|t| format!(" ({t})")).unwrap_or_default();

desktop/bundle/src/mac.rs

@@ -56,6 +56,13 @@ impl App {
 		app_event_scheduler: AppEventScheduler,
 		launch_documents: Vec<PathBuf>,
 	) -> Self {
+		let ctrlc_app_event_scheduler = app_event_scheduler.clone();
+		ctrlc::set_handler(move || {
+			tracing::info!("Termination signal received, exiting...");
+			ctrlc_app_event_scheduler.schedule(AppEvent::CloseWindow);
+		})
+		.expect("Error setting Ctrl-C handler");
+
 		let rendering_app_event_scheduler = app_event_scheduler.clone();
 		let (start_render_sender, start_render_receiver) = std::sync::mpsc::sync_channel(1);
 		std::thread::spawn(move || {
@@ -365,6 +372,7 @@ impl App {
 				tracing::info!("Exiting main event loop");
 				event_loop.exit();
 			}
+			#[cfg(target_os = "macos")]
 			AppEvent::MenuEvent { id } => {
 				self.dispatch_desktop_wrapper_message(DesktopWrapperMessage::MenuEvent { id });
 			}

desktop/src/app.rs

@@ -11,7 +11,7 @@ use super::CefContext;
 use super::singlethreaded::SingleThreadedCefContext;
 use crate::cef::CefEventHandler;
 use crate::cef::consts::{RESOURCE_DOMAIN, RESOURCE_SCHEME};
-use crate::cef::dirs::create_instance_dir;
+use crate::cef::dirs::{create_instance_dir, delete_instance_dirs};
 use crate::cef::input::InputState;
 use crate::cef::internal::{BrowserProcessAppImpl, BrowserProcessClientImpl, RenderProcessAppImpl, SchemeHandlerFactoryImpl};
 
@@ -85,6 +85,7 @@ impl<H: CefEventHandler> CefContextBuilder<H> {
 
 	#[cfg(target_os = "macos")]
 	pub(crate) fn initialize(self, event_handler: H, disable_gpu_acceleration: bool) -> Result<impl CefContext, InitError> {
+		delete_instance_dirs();
 		let instance_dir = create_instance_dir();
 
 		let exe = std::env::current_exe().expect("cannot get current exe path");
@@ -105,6 +106,7 @@ impl<H: CefEventHandler> CefContextBuilder<H> {
 
 	#[cfg(not(target_os = "macos"))]
 	pub(crate) fn initialize(self, event_handler: H, disable_gpu_acceleration: bool) -> Result<impl CefContext, InitError> {
+		delete_instance_dirs();
 		let instance_dir = create_instance_dir();
 
 		let settings = Settings {

desktop/src/cef/context/builder.rs

@@ -43,7 +43,19 @@ impl CefContext for SingleThreadedCefContext {
 impl Drop for SingleThreadedCefContext {
 	fn drop(&mut self) {
 		cef::shutdown();
-		std::fs::remove_dir_all(&self.instance_dir).expect("Failed to remove CEF cache directory");
+
+		// Sometimes some CEF processes still linger at this point and hold file handles to the cache directory.
+		// To mitigate this, we try to remove the directory multiple times with some delay.
+		// TODO: find a better solution if possible.
+		for _ in 0..30 {
+			match std::fs::remove_dir_all(&self.instance_dir) {
+				Ok(_) => break,
+				Err(e) => {
+					tracing::warn!("Failed to remove CEF cache directory, retrying...: {e}");
+					std::thread::sleep(std::time::Duration::from_millis(100));
+				}
+			}
+		}
 	}
 }
 

desktop/src/cef/context/singlethreaded.rs

@@ -1,12 +1,24 @@
 use std::path::PathBuf;
 
-use crate::dirs::{ensure_dir_exists, graphite_data_dir};
+use crate::dirs::{app_data_dir, ensure_dir_exists};
 
 static CEF_DIR_NAME: &str = "browser";
 
+pub(crate) fn delete_instance_dirs() {
+	let cef_dir = app_data_dir().join(CEF_DIR_NAME);
+	if let Ok(entries) = std::fs::read_dir(&cef_dir) {
+		for entry in entries.flatten() {
+			let path = entry.path();
+			if path.is_dir() {
+				let _ = std::fs::remove_dir_all(&path);
+			}
+		}
+	}
+}
+
 pub(crate) fn create_instance_dir() -> PathBuf {
 	let instance_id: String = (0..32).map(|_| format!("{:x}", rand::random::<u8>() % 16)).collect();
-	let path = graphite_data_dir().join(CEF_DIR_NAME).join(instance_id);
+	let path = app_data_dir().join(CEF_DIR_NAME).join(instance_id);
 	ensure_dir_exists(&path);
 	path
 }

desktop/src/cef/dirs.rs

@@ -1,12 +1,12 @@
-use cef::sys::{cef_event_flags_t, cef_key_event_type_t, cef_mouse_button_type_t};
+use cef::sys::{cef_key_event_type_t, cef_mouse_button_type_t};
 use cef::{Browser, ImplBrowser, ImplBrowserHost, KeyEvent, MouseEvent};
 use winit::event::{ButtonSource, ElementState, MouseButton, MouseScrollDelta, WindowEvent};
 
 mod keymap;
 use keymap::{ToCharRepresentation, ToNativeKeycode, ToVKBits};
 
 mod state;
-pub(crate) use state::InputState;
+pub(crate) use state::{CefModifiers, InputState};
 
 use super::consts::{PINCH_ZOOM_SPEED, SCROLL_LINE_HEIGHT, SCROLL_LINE_WIDTH, SCROLL_SPEED_X, SCROLL_SPEED_Y};
 
@@ -129,9 +129,10 @@ pub(crate) fn handle_window_event(browser: &Browser, input_state: &mut InputStat
 			}
 			let Some(host) = browser.host() else { return };
 
-			let mut mouse_event: MouseEvent = input_state.into();
-			mouse_event.modifiers |= cef_event_flags_t::EVENTFLAG_CONTROL_DOWN.0 as u32;
-			mouse_event.modifiers |= cef_event_flags_t::EVENTFLAG_PRECISION_SCROLLING_DELTA.0 as u32;
+			let mouse_event = MouseEvent {
+				modifiers: CefModifiers::PINCH_MODIFIERS.into(),
+				..input_state.into()
+			};
 
 			let delta = (delta * PINCH_ZOOM_SPEED).round() as i32;