From ff09c3a256136b70cfc6e9bcf88c33a05cba4523 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Joakim=20Frosteg=C3=A5rd?= <joakim.frostegard@gmail.com>
Date: Mon, 23 Nov 2020 14:38:32 +0100
Subject: [PATCH] macOS: add timer triggering WindowHandler::on_frame (#58)

* macOS: add simple NSTimer that triggers WindowHandler::on_frame

* macOS: invalidate frame timer when releasing view

* macOS: clean up
---
 src/macos/view.rs   | 30 +++++++++++++++++++++++++++---
 src/macos/window.rs | 29 ++++++++++++++++++++++++++++-
 2 files changed, 55 insertions(+), 4 deletions(-)

diff --git a/src/macos/view.rs b/src/macos/view.rs
index 8d958c3..f9f6f3b 100644
--- a/src/macos/view.rs
+++ b/src/macos/view.rs
@@ -20,7 +20,7 @@ use crate::{
 };
 use crate::MouseEvent::{ButtonPressed, ButtonReleased};
 
-use super::window::{WindowState, WINDOW_STATE_IVAR_NAME};
+use super::window::{WindowState, WINDOW_STATE_IVAR_NAME, FRAME_TIMER_IVAR_NAME};
 
 
 pub(super) unsafe fn create_view<H: WindowHandler>(
@@ -67,6 +67,11 @@ unsafe fn create_view_class<H: WindowHandler>() -> &'static Class {
         accepts_first_mouse::<H> as extern "C" fn(&Object, Sel, id) -> BOOL
     );
 
+    class.add_method(
+        sel!(triggerOnFrame:),
+        trigger_on_frame::<H> as extern "C" fn(&Object, Sel, id)
+    );
+
     class.add_method(
         sel!(release),
         release::<H> as extern "C" fn(&Object, Sel)
@@ -144,6 +149,7 @@ unsafe fn create_view_class<H: WindowHandler>() -> &'static Class {
     );
 
     class.add_ivar::<*mut c_void>(WINDOW_STATE_IVAR_NAME);
+    class.add_ivar::<*mut c_void>(FRAME_TIMER_IVAR_NAME);
 
     class.register()
 }
@@ -174,6 +180,19 @@ extern "C" fn accepts_first_mouse<H: WindowHandler>(
 }
 
 
+extern "C" fn trigger_on_frame<H: WindowHandler>(
+    this: &Object,
+    _sel: Sel,
+    _event: id
+){
+    let state: &mut WindowState<H> = unsafe {
+        WindowState::from_field(this)
+    };
+
+    state.trigger_frame();
+}
+
+
 extern "C" fn release<H: WindowHandler>(this: &Object, _sel: Sel) {
     unsafe {
         let superclass = msg_send![this, superclass];
@@ -185,11 +204,16 @@ extern "C" fn release<H: WindowHandler>(this: &Object, _sel: Sel) {
         let retain_count: usize = msg_send![this, retainCount];
 
         if retain_count == 1 {
+            // Invalidate frame timer
+            let frame_timer_ptr: *mut c_void = *this.get_ivar(
+                FRAME_TIMER_IVAR_NAME
+            );
+            let _: () = msg_send![frame_timer_ptr as id, invalidate];
+
+            // Drop WindowState
             let state_ptr: *mut c_void = *this.get_ivar(
                 WINDOW_STATE_IVAR_NAME
             );
-
-            // Drop WindowState
             Arc::from_raw(state_ptr as *mut WindowState<H>);
 
             // Delete class
diff --git a/src/macos/window.rs b/src/macos/window.rs
index 5e228f5..7194eb8 100644
--- a/src/macos/window.rs
+++ b/src/macos/window.rs
@@ -9,7 +9,7 @@ use cocoa::appkit::{
     NSApp, NSApplication, NSApplicationActivationPolicyRegular,
     NSBackingStoreBuffered, NSWindow, NSWindowStyleMask,
 };
-use cocoa::base::{id, nil, NO};
+use cocoa::base::{id, nil, NO, YES};
 use cocoa::foundation::{NSAutoreleasePool, NSPoint, NSRect, NSSize, NSString};
 use keyboard_types::KeyboardEvent;
 
@@ -30,6 +30,8 @@ use super::keyboard::KeyboardState;
 /// view class.
 pub(super) const WINDOW_STATE_IVAR_NAME: &str = "WINDOW_STATE_IVAR_NAME";
 
+pub(super) const FRAME_TIMER_IVAR_NAME: &str = "FRAME_TIMER";
+
 
 pub struct Window {
     /// Only set if we created the parent window, i.e. we are running in
@@ -172,6 +174,27 @@ impl Window {
             );
         }
 
+        // Activate timer after window handler is setup and save a pointer to
+        // it, so that it can be invalidated when view is released.
+        unsafe {
+            let timer_interval = 0.015;
+            let selector = sel!(triggerOnFrame:);
+
+            let timer: id = msg_send![
+                ::objc::class!(NSTimer),
+                scheduledTimerWithTimeInterval:timer_interval
+                target:window_state_arc.window.ns_view
+                selector:selector
+                userInfo:nil
+                repeats:YES
+            ];
+
+            (*window_state_arc.window.ns_view).set_ivar(
+                FRAME_TIMER_IVAR_NAME,
+                timer as *mut c_void,
+            )
+        }
+
         WindowHandle
     }
 }
@@ -200,6 +223,10 @@ impl <H: WindowHandler>WindowState<H> {
         self.window_handler.on_event(&mut self.window, event);
     }
 
+    pub(super) fn trigger_frame(&mut self){
+        self.window_handler.on_frame()
+    }
+
     pub(super) fn process_native_key_event(
         &mut self,
         event: *mut Object