Clean up iOS class declaration (#2462)

* Begin abstraction over UIKit

* Clean up UIWindow override declaration

* Clean up UIApplication delegate declaration

* Clean up UIViewController override declaration

* Finalize objc -> objc2 rename

Cargo.toml

@@ -62,7 +62,7 @@ ndk = "0.7.0"
 ndk-glue = "0.7.0"
 
 [target.'cfg(any(target_os = "ios", target_os = "macos"))'.dependencies]
-objc = { version = "=0.3.0-beta.3", package = "objc2" }
+objc2 = "=0.3.0-beta.3"
 
 [target.'cfg(target_os = "macos")'.dependencies]
 core-foundation = "0.9.3"

src/lib.rs

@@ -145,11 +145,6 @@ extern crate log;
 extern crate serde;
 #[macro_use]
 extern crate bitflags;
-#[cfg(target_os = "ios")]
-#[macro_use]
-extern crate objc;
-#[cfg(target_os = "macos")]
-extern crate objc as objc2;
 
 pub mod dpi;
 #[macro_use]

src/platform_impl/ios/app_state.rs

@@ -9,8 +9,9 @@ use std::{
     time::Instant,
 };
 
-use objc::foundation::{NSInteger, NSUInteger};
+use objc2::foundation::{NSInteger, NSUInteger};
-use objc::runtime::Object;
+use objc2::runtime::Object;
+use objc2::{class, msg_send, sel};
 use once_cell::sync::Lazy;
 
 use crate::{

src/platform_impl/ios/event_loop.rs

@@ -7,7 +7,8 @@ use std::{
     sync::mpsc::{self, Receiver, Sender},
 };
 
-use objc::runtime::Object;
+use objc2::runtime::Object;
+use objc2::{class, msg_send, ClassType};
 use raw_window_handle::{RawDisplayHandle, UiKitDisplayHandle};
 
 use crate::{
@@ -91,7 +92,6 @@ impl<T: 'static> EventLoop<T> {
                  `EventLoopProxy` might be helpful"
             );
             SINGLETON_INIT = true;
-            view::create_delegate_class();
         }
 
         let (sender_to_clone, receiver) = mpsc::channel();
@@ -128,11 +128,14 @@ impl<T: 'static> EventLoop<T> {
                 event_loop: self.window_target,
             }));
 
+            // Ensure application delegate is initialized
+            view::WinitApplicationDelegate::class();
+
             UIApplicationMain(
                 0,
                 ptr::null(),
                 nil,
-                NSStringRust::alloc(nil).init_str("AppDelegate"),
+                NSStringRust::alloc(nil).init_str("WinitApplicationDelegate"),
             );
             unreachable!()
         }

src/platform_impl/ios/ffi.rs

@@ -2,8 +2,10 @@
 
 use std::{convert::TryInto, ffi::CString, ops::BitOr, os::raw::*};
 
-use objc::foundation::{NSInteger, NSUInteger};
+use objc2::encode::{Encode, Encoding};
-use objc::{runtime::Object, Encode, Encoding};
+use objc2::foundation::{NSInteger, NSUInteger};
+use objc2::runtime::Object;
+use objc2::{class, msg_send};
 
 use crate::{
     dpi::LogicalSize,

src/platform_impl/ios/mod.rs

@@ -63,7 +63,7 @@
 // window size/position.
 macro_rules! assert_main_thread {
     ($($t:tt)*) => {
-        if !::objc::foundation::is_main_thread() {
+        if !::objc2::foundation::is_main_thread() {
             panic!($($t)*);
         }
     };
@@ -73,6 +73,7 @@ mod app_state;
 mod event_loop;
 mod ffi;
 mod monitor;
+mod uikit;
 mod view;
 mod window;
 

src/platform_impl/ios/monitor.rs

@@ -4,7 +4,8 @@ use std::{
     ops::{Deref, DerefMut},
 };
 
-use objc::foundation::{NSInteger, NSUInteger};
+use objc2::foundation::{NSInteger, NSUInteger};
+use objc2::{class, msg_send};
 
 use crate::{
     dpi::{PhysicalPosition, PhysicalSize},

src/platform_impl/ios/uikit/mod.rs

@@ -0,0 +1,12 @@
+#![deny(unsafe_op_in_unsafe_fn)]
+
+mod responder;
+mod view;
+mod view_controller;
+mod window;
+
+pub(crate) use self::responder::UIResponder;
+#[allow(unused)]
+pub(crate) use self::view::UIView;
+pub(crate) use self::view_controller::UIViewController;
+pub(crate) use self::window::UIWindow;

src/platform_impl/ios/uikit/responder.rs

@@ -0,0 +1,11 @@
+use objc2::foundation::NSObject;
+use objc2::{extern_class, ClassType};
+
+extern_class!(
+    #[derive(Debug, PartialEq, Eq, Hash)]
+    pub(crate) struct UIResponder;
+
+    unsafe impl ClassType for UIResponder {
+        type Super = NSObject;
+    }
+);

src/platform_impl/ios/uikit/view.rs

@@ -0,0 +1,14 @@
+use objc2::foundation::NSObject;
+use objc2::{extern_class, ClassType};
+
+use super::UIResponder;
+
+extern_class!(
+    #[derive(Debug, PartialEq, Eq, Hash)]
+    pub(crate) struct UIView;
+
+    unsafe impl ClassType for UIView {
+        #[inherits(NSObject)]
+        type Super = UIResponder;
+    }
+);

src/platform_impl/ios/uikit/view_controller.rs

@@ -0,0 +1,14 @@
+use objc2::foundation::NSObject;
+use objc2::{extern_class, ClassType};
+
+use super::UIResponder;
+
+extern_class!(
+    #[derive(Debug, PartialEq, Eq, Hash)]
+    pub(crate) struct UIViewController;
+
+    unsafe impl ClassType for UIViewController {
+        #[inherits(NSObject)]
+        type Super = UIResponder;
+    }
+);

src/platform_impl/ios/uikit/window.rs

@@ -0,0 +1,14 @@
+use objc2::foundation::NSObject;
+use objc2::{extern_class, ClassType};
+
+use super::UIResponder;
+
+extern_class!(
+    #[derive(Debug, PartialEq, Eq, Hash)]
+    pub(crate) struct UIWindow;
+
+    unsafe impl ClassType for UIWindow {
+        #[inherits(NSObject)]
+        type Super = UIResponder;
+    }
+);

src/platform_impl/ios/view.rs

@@ -1,16 +1,17 @@
 use std::collections::HashMap;
 
-use objc::{
+use objc2::declare::ClassBuilder;
-    declare::ClassBuilder,
+use objc2::foundation::NSObject;
-    runtime::{Bool, Class, Object, Sel},
+use objc2::runtime::{Bool, Class, Object, Sel};
-};
+use objc2::{class, declare_class, msg_send, sel, ClassType};
 
+use super::uikit::{UIResponder, UIViewController, UIWindow};
 use crate::{
     dpi::PhysicalPosition,
     event::{DeviceId as RootDeviceId, Event, Force, Touch, TouchPhase, WindowEvent},
     platform::ios::MonitorHandleExtIOS,
     platform_impl::platform::{
-        app_state::{self, OSCapabilities},
+        app_state,
         event_loop::{self, EventProxy, EventWrapper},
         ffi::{
             id, nil, CGFloat, CGPoint, CGRect, UIForceTouchCapability, UIInterfaceOrientationMask,
@@ -22,64 +23,6 @@ use crate::{
     window::{Fullscreen, WindowAttributes, WindowId as RootWindowId},
 };
 
-macro_rules! add_property {
-    (
-        $decl:ident,
-        $name:ident: $t:ty,
-        $setter_name:ident: |$object:ident| $after_set:expr,
-        $getter_name:ident,
-    ) => {
-        add_property!(
-            $decl,
-            $name: $t,
-            $setter_name: true, |_, _|{}; |$object| $after_set,
-            $getter_name,
-        )
-    };
-    (
-        $decl:ident,
-        $name:ident: $t:ty,
-        $setter_name:ident: $capability:expr, $err:expr; |$object:ident| $after_set:expr,
-        $getter_name:ident,
-    ) => {
-        {
-            const VAR_NAME: &'static str = concat!("_", stringify!($name));
-            $decl.add_ivar::<$t>(VAR_NAME);
-            let setter = if $capability {
-                #[allow(non_snake_case)]
-                extern "C" fn $setter_name($object: &mut Object, _: Sel, value: $t) {
-                    unsafe {
-                        $object.set_ivar::<$t>(VAR_NAME, value);
-                    }
-                    $after_set
-                }
-                $setter_name
-            } else {
-                #[allow(non_snake_case)]
-                extern "C" fn $setter_name($object: &mut Object, _: Sel, value: $t) {
-                    unsafe {
-                        $object.set_ivar::<$t>(VAR_NAME, value);
-                    }
-                    $err(&app_state::os_capabilities(), "ignoring")
-                }
-                $setter_name
-            };
-            #[allow(non_snake_case)]
-            extern "C" fn $getter_name($object: &Object, _: Sel) -> $t {
-                unsafe { *$object.ivar::<$t>(VAR_NAME) }
-            }
-            $decl.add_method(
-                sel!($setter_name:),
-                setter as extern "C" fn(_, _, _),
-            );
-            $decl.add_method(
-                sel!($getter_name),
-                $getter_name as extern "C" fn(_, _) -> _,
-            );
-        }
-    };
-}
-
 // requires main thread
 unsafe fn get_view_class(root_view_class: &'static Class) -> &'static Class {
     static mut CLASSES: Option<HashMap<*const Class, &'static Class>> = None;
@@ -312,116 +255,127 @@ unsafe fn get_view_class(root_view_class: &'static Class) -> &'static Class {
     })
 }
 
-// requires main thread
+declare_class!(
-unsafe fn get_view_controller_class() -> &'static Class {
+    struct WinitViewController {
-    static mut CLASS: Option<&'static Class> = None;
+        _prefers_status_bar_hidden: bool,
-    if CLASS.is_none() {
+        _prefers_home_indicator_auto_hidden: bool,
+        _supported_orientations: UIInterfaceOrientationMask,
+        _preferred_screen_edges_deferring_system_gestures: UIRectEdge,
+    }
+
+    unsafe impl ClassType for WinitViewController {
+        #[inherits(UIResponder, NSObject)]
+        type Super = UIViewController;
+        const NAME: &'static str = "WinitUIViewController";
+    }
+
+    unsafe impl WinitViewController {
+        #[sel(shouldAutorotate)]
+        fn should_autorotate(&self) -> bool {
+            true
+        }
+    }
+
+    unsafe impl WinitViewController {
+        #[sel(prefersStatusBarHidden)]
+        fn prefers_status_bar_hidden(&self) -> bool {
+            *self._prefers_status_bar_hidden
+        }
+
+        #[sel(setPrefersStatusBarHidden:)]
+        fn set_prefers_status_bar_hidden(&mut self, val: bool) {
+            *self._prefers_status_bar_hidden = val;
+            unsafe {
+                let _: () = msg_send![self, setNeedsStatusBarAppearanceUpdate];
+            }
+        }
+
+        #[sel(prefersHomeIndicatorAutoHidden)]
+        fn prefers_home_indicator_auto_hidden(&self) -> bool {
+            *self._prefers_home_indicator_auto_hidden
+        }
+
+        #[sel(setPrefersHomeIndicatorAutoHidden:)]
+        fn set_prefers_home_indicator_auto_hidden(&mut self, val: bool) {
+            *self._prefers_home_indicator_auto_hidden = val;
             let os_capabilities = app_state::os_capabilities();
-
+            if os_capabilities.home_indicator_hidden {
-        let uiviewcontroller_class = class!(UIViewController);
+                unsafe {
-
+                    let _: () = msg_send![self, setNeedsUpdateOfHomeIndicatorAutoHidden];
-        extern "C" fn should_autorotate(_: &Object, _: Sel) -> Bool {
+                }
-            Bool::YES
+            } else {
+                os_capabilities.home_indicator_hidden_err_msg("ignoring")
+            }
         }
 
-        let mut decl = ClassBuilder::new("WinitUIViewController", uiviewcontroller_class)
+        #[sel(supportedInterfaceOrientations)]
-            .expect("Failed to declare class `WinitUIViewController`");
+        fn supported_orientations(&self) -> UIInterfaceOrientationMask {
-        decl.add_method(
+            *self._supported_orientations
-            sel!(shouldAutorotate),
+        }
-            should_autorotate as extern "C" fn(_, _) -> _,
+
+        #[sel(setSupportedInterfaceOrientations:)]
+        fn set_supported_orientations(&mut self, val: UIInterfaceOrientationMask) {
+            *self._supported_orientations = val;
+            unsafe {
+                let _: () = msg_send![
+                    UIViewController::class(),
+                    attemptRotationToDeviceOrientation
+                ];
+            }
+        }
+
+        #[sel(preferredScreenEdgesDeferringSystemGestures)]
+        fn preferred_screen_edges_deferring_system_gestures(&self) -> UIRectEdge {
+            *self._preferred_screen_edges_deferring_system_gestures
+        }
+
+        #[sel(setPreferredScreenEdgesDeferringSystemGestures:)]
+        fn set_preferred_screen_edges_deferring_system_gestures(&mut self, val: UIRectEdge) {
+            *self._preferred_screen_edges_deferring_system_gestures = val;
+            let os_capabilities = app_state::os_capabilities();
+            if os_capabilities.defer_system_gestures {
+                unsafe {
+                    let _: () = msg_send![self, setNeedsUpdateOfScreenEdgesDeferringSystemGestures];
+                }
+            } else {
+                os_capabilities.defer_system_gestures_err_msg("ignoring")
+            }
+        }
+    }
 );
-        add_property! {
+
-            decl,
+declare_class!(
-            prefers_status_bar_hidden: Bool,
+    struct WinitUIWindow {}
-            setPrefersStatusBarHidden: |object| {
+
-                unsafe {
+    unsafe impl ClassType for WinitUIWindow {
-                    let _: () = msg_send![object, setNeedsStatusBarAppearanceUpdate];
+        #[inherits(UIResponder, NSObject)]
-                }
+        type Super = UIWindow;
-            },
-            prefersStatusBarHidden,
-        }
-        add_property! {
-            decl,
-            prefers_home_indicator_auto_hidden: Bool,
-            setPrefersHomeIndicatorAutoHidden:
-                os_capabilities.home_indicator_hidden,
-                OSCapabilities::home_indicator_hidden_err_msg;
-                |object| {
-                    unsafe {
-                        let _: () = msg_send![object, setNeedsUpdateOfHomeIndicatorAutoHidden];
-                    }
-                },
-            prefersHomeIndicatorAutoHidden,
-        }
-        add_property! {
-            decl,
-            supported_orientations: UIInterfaceOrientationMask,
-            setSupportedInterfaceOrientations: |object| {
-                unsafe {
-                    let _: () = msg_send![class!(UIViewController), attemptRotationToDeviceOrientation];
-                }
-            },
-            supportedInterfaceOrientations,
-        }
-        add_property! {
-            decl,
-            preferred_screen_edges_deferring_system_gestures: UIRectEdge,
-            setPreferredScreenEdgesDeferringSystemGestures:
-                os_capabilities.defer_system_gestures,
-                OSCapabilities::defer_system_gestures_err_msg;
-                |object| {
-                    unsafe {
-                        let _: () = msg_send![object, setNeedsUpdateOfScreenEdgesDeferringSystemGestures];
-                    }
-                },
-            preferredScreenEdgesDeferringSystemGestures,
-        }
-        CLASS = Some(decl.register());
-    }
-    CLASS.unwrap()
     }
 
-// requires main thread
+    unsafe impl WinitUIWindow {
-unsafe fn get_window_class() -> &'static Class {
+        #[sel(becomeKeyWindow)]
-    static mut CLASS: Option<&'static Class> = None;
+        fn become_key_window(&self) {
-    if CLASS.is_none() {
-        let uiwindow_class = class!(UIWindow);
-
-        extern "C" fn become_key_window(object: &Object, _: Sel) {
             unsafe {
                 app_state::handle_nonuser_event(EventWrapper::StaticEvent(Event::WindowEvent {
-                    window_id: RootWindowId(object.into()),
+                    window_id: RootWindowId((&*****self).into()),
                     event: WindowEvent::Focused(true),
                 }));
-                let _: () = msg_send![super(object, class!(UIWindow)), becomeKeyWindow];
+                let _: () = msg_send![super(self), becomeKeyWindow];
             }
         }
 
-        extern "C" fn resign_key_window(object: &Object, _: Sel) {
+        #[sel(resignKeyWindow)]
+        fn resign_key_window(&self) {
             unsafe {
                 app_state::handle_nonuser_event(EventWrapper::StaticEvent(Event::WindowEvent {
-                    window_id: RootWindowId(object.into()),
+                    window_id: RootWindowId((&*****self).into()),
                     event: WindowEvent::Focused(false),
                 }));
-                let _: () = msg_send![super(object, class!(UIWindow)), resignKeyWindow];
+                let _: () = msg_send![super(self), resignKeyWindow];
+            }
         }
     }
-
-        let mut decl = ClassBuilder::new("WinitUIWindow", uiwindow_class)
-            .expect("Failed to declare class `WinitUIWindow`");
-        decl.add_method(
-            sel!(becomeKeyWindow),
-            become_key_window as extern "C" fn(_, _),
 );
-        decl.add_method(
-            sel!(resignKeyWindow),
-            resign_key_window as extern "C" fn(_, _),
-        );
-
-        CLASS = Some(decl.register());
-    }
-    CLASS.unwrap()
-}
 
 // requires main thread
 pub(crate) unsafe fn create_view(
@@ -449,7 +403,7 @@ pub(crate) unsafe fn create_view_controller(
     platform_attributes: &PlatformSpecificWindowBuilderAttributes,
     view: id,
 ) -> id {
-    let class = get_view_controller_class();
+    let class = WinitViewController::class();
 
     let view_controller: id = msg_send![class, alloc];
     assert!(
@@ -499,9 +453,7 @@ pub(crate) unsafe fn create_window(
     frame: CGRect,
     view_controller: id,
 ) -> id {
-    let class = get_window_class();
+    let window: id = msg_send![WinitUIWindow::class(), alloc];
-
-    let window: id = msg_send![class, alloc];
     assert!(!window.is_null(), "Failed to create `UIWindow` instance");
     let window: id = msg_send![window, initWithFrame: frame];
     assert!(
@@ -532,26 +484,40 @@ pub(crate) unsafe fn create_window(
     window
 }
 
-pub fn create_delegate_class() {
+declare_class!(
-    extern "C" fn did_finish_launching(_: &mut Object, _: Sel, _: id, _: id) -> Bool {
+    pub struct WinitApplicationDelegate {}
+
+    unsafe impl ClassType for WinitApplicationDelegate {
+        type Super = NSObject;
+    }
+
+    // UIApplicationDelegate protocol
+    unsafe impl WinitApplicationDelegate {
+        #[sel(application:didFinishLaunchingWithOptions:)]
+        fn did_finish_launching(&self, _: id, _: id) -> bool {
             unsafe {
                 app_state::did_finish_launching();
             }
-        Bool::YES
+            true
         }
 
-    extern "C" fn did_become_active(_: &Object, _: Sel, _: id) {
+        #[sel(applicationDidBecomeActive:)]
+        fn did_become_active(&self, _: id) {
             unsafe { app_state::handle_nonuser_event(EventWrapper::StaticEvent(Event::Resumed)) }
         }
 
-    extern "C" fn will_resign_active(_: &Object, _: Sel, _: id) {
+        #[sel(applicationWillResignActive:)]
+        fn will_resign_active(&self, _: id) {
             unsafe { app_state::handle_nonuser_event(EventWrapper::StaticEvent(Event::Suspended)) }
         }
 
-    extern "C" fn will_enter_foreground(_: &Object, _: Sel, _: id) {}
+        #[sel(applicationWillEnterForeground:)]
-    extern "C" fn did_enter_background(_: &Object, _: Sel, _: id) {}
+        fn will_enter_foreground(&self, _: id) {}
+        #[sel(applicationDidEnterBackground:)]
+        fn did_enter_background(&self, _: id) {}
 
-    extern "C" fn will_terminate(_: &Object, _: Sel, _: id) {
+        #[sel(applicationWillTerminate:)]
+        fn will_terminate(&self, _: id) {
             unsafe {
                 let app: id = msg_send![class!(UIApplication), sharedApplication];
                 let windows: id = msg_send![app, windows];
@@ -562,7 +528,7 @@ pub fn create_delegate_class() {
                     if window == nil {
                         break;
                     }
-                let is_winit_window = msg_send![window, isKindOfClass: class!(WinitUIWindow)];
+                    let is_winit_window = msg_send![window, isKindOfClass: WinitUIWindow::class()];
                     if is_winit_window {
                         events.push(EventWrapper::StaticEvent(Event::WindowEvent {
                             window_id: RootWindowId(window.into()),
@@ -574,39 +540,5 @@ pub fn create_delegate_class() {
                 app_state::terminated();
             }
         }
-
-    let ui_responder = class!(UIResponder);
-    let mut decl = ClassBuilder::new("AppDelegate", ui_responder)
-        .expect("Failed to declare class `AppDelegate`");
-
-    unsafe {
-        decl.add_method(
-            sel!(application:didFinishLaunchingWithOptions:),
-            did_finish_launching as extern "C" fn(_, _, _, _) -> _,
-        );
-
-        decl.add_method(
-            sel!(applicationDidBecomeActive:),
-            did_become_active as extern "C" fn(_, _, _),
-        );
-        decl.add_method(
-            sel!(applicationWillResignActive:),
-            will_resign_active as extern "C" fn(_, _, _),
-        );
-        decl.add_method(
-            sel!(applicationWillEnterForeground:),
-            will_enter_foreground as extern "C" fn(_, _, _),
-        );
-        decl.add_method(
-            sel!(applicationDidEnterBackground:),
-            did_enter_background as extern "C" fn(_, _, _),
-        );
-
-        decl.add_method(
-            sel!(applicationWillTerminate:),
-            will_terminate as extern "C" fn(_, _, _),
-        );
-
-        decl.register();
-    }
     }
+);

src/platform_impl/ios/window.rs

@@ -3,7 +3,8 @@ use std::{
     ops::{Deref, DerefMut},
 };
 
-use objc::runtime::{Class, Object};
+use objc2::runtime::{Class, Object};
+use objc2::{class, msg_send};
 use raw_window_handle::{RawDisplayHandle, RawWindowHandle, UiKitDisplayHandle, UiKitWindowHandle};
 
 use crate::{