Extract CEF rendered UI into a separate process and crate

desktop/ui/src/platform/mac.rs

@@ -0,0 +1,63 @@
+use objc2::rc::Retained;
+use objc2::runtime::Bool;
+use objc2::{ClassType, define_class, msg_send};
+use objc2_app_kit::{NSApplication, NSApplicationActivationPolicy, NSEvent, NSResponder};
+use objc2_foundation::NSObject;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::time::Duration;
+
+use cef::application_mac::{CefAppProtocol, CrAppControlProtocol, CrAppProtocol};
+
+static HANDLING_SEND_EVENT: AtomicBool = AtomicBool::new(false);
+
+define_class!(
+	#[unsafe(super(NSApplication, NSResponder, NSObject))]
+	#[name = "GraphiteCefHostApplication"]
+	struct CefHostApplication;
+
+	unsafe impl CrAppProtocol for CefHostApplication {
+		#[unsafe(method(isHandlingSendEvent))]
+		fn is_handling_send_event(&self) -> Bool {
+			Bool::new(HANDLING_SEND_EVENT.load(Ordering::Relaxed))
+		}
+	}
+
+	unsafe impl CrAppControlProtocol for CefHostApplication {
+		#[unsafe(method(setHandlingSendEvent:))]
+		fn set_handling_send_event(&self, handling: Bool) {
+			HANDLING_SEND_EVENT.store(handling.as_bool(), Ordering::Relaxed);
+		}
+	}
+
+	unsafe impl CefAppProtocol for CefHostApplication {}
+
+	impl CefHostApplication {
+		#[unsafe(method(sendEvent:))]
+		fn send_event(&self, event: &NSEvent) {
+			let was_handling = HANDLING_SEND_EVENT.swap(true, Ordering::Relaxed);
+			let _: () = unsafe { msg_send![super(self), sendEvent: event] };
+			HANDLING_SEND_EVENT.store(was_handling, Ordering::Relaxed);
+		}
+	}
+);
+
+pub(crate) fn install_application() {
+	let app: Retained<NSApplication> = unsafe { msg_send![CefHostApplication::class(), sharedApplication] };
+	app.setActivationPolicy(NSApplicationActivationPolicy::Prohibited);
+}
+
+pub(crate) fn spawn_parent_watchdog(main_pid: u32) {
+	let result = std::thread::Builder::new().name("parent-watchdog".to_string()).spawn(move || {
+		loop {
+			// SAFETY: getppid is always safe to call.
+			if unsafe { libc::getppid() } as u32 != main_pid {
+				tracing::warn!("Main process is gone, exiting CEF host");
+				std::process::exit(0);
+			}
+			std::thread::sleep(Duration::from_millis(500));
+		}
+	});
+	if let Err(e) = result {
+		tracing::error!("Failed to spawn the parent watchdog: {e}");
+	}
+}