Desktop: Register the Graphite app as a file handler on Mac (#4106)

* Desktop: Implement native file open handler

* Desktop: Register file types on Mac

* Review

desktop/src/window/mac.rs

@@ -26,8 +26,8 @@ impl super::NativeWindow for NativeWindowImpl {
 	}
 
 	fn new(_window: &dyn Window, app_event_scheduler: AppEventScheduler) -> Self {
+		app::setup(app_event_scheduler.clone());
 		let menu = menu::Menu::new(app_event_scheduler);
-
 		NativeWindowImpl { menu }
 	}
 

desktop/src/window/mac/app.rs

@@ -1,6 +1,22 @@
-use objc2::{ClassType, define_class, msg_send};
-use objc2_app_kit::{NSApplication, NSEvent, NSEventType, NSResponder};
-use objc2_foundation::NSObject;
+use std::ffi::CStr;
+use std::ffi::OsStr;
+use std::ops::Deref;
+use std::os::unix::ffi::OsStrExt;
+use std::path::PathBuf;
+use std::sync::{Mutex, Once};
+
+use objc2::rc::Retained;
+use objc2::runtime::ProtocolObject;
+use objc2::{ClassType, MainThreadMarker, MainThreadOnly, define_class, msg_send};
+use objc2_app_kit::{NSApplication, NSApplicationDelegate, NSEvent, NSEventType, NSResponder};
+use objc2_foundation::{NSArray, NSObject, NSObjectProtocol, NSURL};
+
+use crate::event::{AppEvent, AppEventScheduler};
+
+static APP_EVENT_SCHEDULER: Mutex<Option<AppEventScheduler>> = Mutex::new(None);
+static INSTALL_DELEGATE: Once = Once::new();
+
+static LAUNCH_DOCUMENTS: Mutex<Vec<PathBuf>> = Mutex::new(Vec::new());
 
 define_class!(
 	#[unsafe(super(NSApplication, NSResponder, NSObject))]
@@ -20,12 +36,63 @@ define_class!(
 	}
 );
 
+define_class!(
+	#[unsafe(super(NSObject))]
+	#[thread_kind = MainThreadOnly]
+	#[name = "GraphiteApplicationDelegate"]
+	struct GraphiteApplicationDelegate;
+
+	unsafe impl NSObjectProtocol for GraphiteApplicationDelegate {}
+
+	unsafe impl NSApplicationDelegate for GraphiteApplicationDelegate {
+		#[unsafe(method(application:openURLs:))]
+		fn application_open_urls(&self, _application: &NSApplication, urls: &NSArray<NSURL>) {
+			let app_event_scheduler = APP_EVENT_SCHEDULER.lock().unwrap();
+
+			let mut pending_paths_to_open = LAUNCH_DOCUMENTS.lock().unwrap();
+
+			for index in 0..urls.count() {
+				let url = urls.objectAtIndex(index);
+				if !url.isFileURL() {
+					tracing::error!("Ignoring macOS open URL event for non-file URL: {:?}", url);
+					continue;
+				}
+
+				let path = unsafe { CStr::from_ptr(url.fileSystemRepresentation().as_ptr()) };
+				let path = PathBuf::from(OsStr::from_bytes(path.to_bytes()));
+
+				pending_paths_to_open.push(path);
+			}
+
+			if let Some(app_event_scheduler) = app_event_scheduler.deref() {
+				app_event_scheduler.schedule(AppEvent::AddLaunchDocuments(std::mem::take(&mut pending_paths_to_open)));
+			}
+		}
+	}
+);
+
 fn instance() -> objc2::rc::Retained<NSApplication> {
 	unsafe { msg_send![GraphiteApplication::class(), sharedApplication] }
 }
 
 pub(super) fn init() {
 	let _ = instance();
+
+	INSTALL_DELEGATE.call_once(|| {
+		let mtm = MainThreadMarker::new().expect("only ever called from main thread");
+		let delegate: Retained<GraphiteApplicationDelegate> = unsafe { msg_send![super(GraphiteApplicationDelegate::alloc(mtm).set_ivars(())), init] };
+		instance().setDelegate(Some(ProtocolObject::from_ref(&*delegate)));
+		std::mem::forget(delegate);
+	});
+}
+
+pub(super) fn setup(app_event_scheduler: AppEventScheduler) {
+	let mut app_event_scheduler_guard = APP_EVENT_SCHEDULER.lock().unwrap();
+
+	let mut pending_paths_to_open = LAUNCH_DOCUMENTS.lock().unwrap();
+	app_event_scheduler.schedule(AppEvent::AddLaunchDocuments(std::mem::take(&mut pending_paths_to_open)));
+
+	*app_event_scheduler_guard = Some(app_event_scheduler);
 }
 
 pub(super) fn hide() {