refactor(linux): reduce channel redirect (#588)

* refactor(linux): reduce channel redirect

* Add version bump in change file

Co-authored-by: Wu Yu Wei <wusyong9104@gmail.com>

.changes/tx-reduce.md

@@ -0,0 +1,5 @@
+---
+"tao": patch
+---
+
+On Linux, reduce channel redirect. Now sending user events and redraw request will send to event loops directly.

src/platform_impl/linux/event_loop.rs

@@ -8,11 +8,11 @@ use std::{
   error::Error,
   process,
   rc::Rc,
-  sync::mpsc::SendError,
   time::Instant,
 };
 
 use cairo::{RectangleInt, Region};
+use crossbeam_channel::SendError;
 use gdk::{Cursor, CursorType, EventKey, EventMask, ScrollDirection, WindowEdge, WindowState};
 use gio::{prelude::*, Cancellable};
 use glib::{source::Priority, Continue, MainContext};
@@ -50,6 +50,8 @@ pub struct EventLoopWindowTarget<T> {
   pub(crate) windows: Rc<RefCell<HashSet<WindowId>>>,
   /// Window requests sender
   pub(crate) window_requests_tx: glib::Sender<(WindowId, WindowRequest)>,
+  /// Draw event sender
+  pub(crate) draw_tx: crossbeam_channel::Sender<WindowId>,
   _marker: std::marker::PhantomData<T>,
 }
 
@@ -98,7 +100,7 @@ pub struct EventLoop<T: 'static> {
   /// Window target.
   window_target: RootELW<T>,
   /// User event sender for EventLoopProxy
-  user_event_tx: glib::Sender<T>,
+  user_event_tx: crossbeam_channel::Sender<Event<'static, T>>,
   /// Event queue of EventLoop
   events: crossbeam_channel::Receiver<Event<'static, T>>,
   /// Draw queue of EventLoop
@@ -134,6 +136,8 @@ impl<T: 'static> EventLoop<T> {
         log::warn!("Failed to send init event to event channel: {}", e);
       }
     });
+    let draw_tx_ = draw_tx.clone();
+    let user_event_tx = event_tx.clone();
 
     // Create event loop window target.
     let (window_requests_tx, window_requests_rx) = glib::MainContext::channel(Priority::default());
@@ -145,19 +149,10 @@ impl<T: 'static> EventLoop<T> {
       app,
       windows: Rc::new(RefCell::new(HashSet::new())),
       window_requests_tx,
+      draw_tx: draw_tx_,
       _marker: std::marker::PhantomData,
     };
 
-    // Create user event channel
-    let (user_event_tx, user_event_rx) = glib::MainContext::channel(Priority::default());
-    let event_tx_ = event_tx.clone();
-    user_event_rx.attach(Some(&context), move |event| {
-      if let Err(e) = event_tx_.send(Event::UserEvent(event)) {
-        log::warn!("Failed to send user event to event channel: {}", e);
-      }
-      Continue(true)
-    });
-
     // Window Request
     window_requests_rx.attach(Some(&context), move |(id, request)| {
       if let Some(window) = app_.window_by_id(id.0) {
@@ -760,13 +755,6 @@ impl<T: 'static> EventLoop<T> {
               Inhibit(false)
             });
           }
-          WindowRequest::Redraw => {
-            if let Err(e) = draw_tx.send(id) {
-              log::warn!("Failed to send redraw event to event channel: {}", e);
-            }
-
-            window.queue_draw();
-          }
           WindowRequest::Menu(m) => match m {
             (None, Some(menu_id)) => {
               if let Err(e) = event_tx.send(Event::MenuEvent {
@@ -1055,7 +1043,7 @@ impl<T: 'static> EventLoop<T> {
 /// Used to send custom events to `EventLoop`.
 #[derive(Debug)]
 pub struct EventLoopProxy<T: 'static> {
-  user_event_tx: glib::Sender<T>,
+  user_event_tx: crossbeam_channel::Sender<Event<'static, T>>,
 }
 
 impl<T: 'static> Clone for EventLoopProxy<T> {
@@ -1075,8 +1063,14 @@ impl<T: 'static> EventLoopProxy<T> {
   pub fn send_event(&self, event: T) -> Result<(), EventLoopClosed<T>> {
     self
       .user_event_tx
-      .send(event)
-      .map_err(|SendError(error)| EventLoopClosed(error))
+      .send(Event::UserEvent(event))
+      .map_err(|SendError(event)| {
+        if let Event::UserEvent(error) = event {
+          EventLoopClosed(error)
+        } else {
+          unreachable!();
+        }
+      })
   }
 }
 

src/platform_impl/linux/window.rs

@@ -63,6 +63,8 @@ pub struct Window {
   maximized: Rc<AtomicBool>,
   minimized: Rc<AtomicBool>,
   fullscreen: RefCell<Option<Fullscreen>>,
+  /// Draw event Sender
+  draw_tx: crossbeam_channel::Sender<WindowId>,
 }
 
 impl Window {
@@ -73,6 +75,7 @@ impl Window {
   ) -> Result<Self, RootOsError> {
     let app = &event_loop_window_target.app;
     let window_requests_tx = event_loop_window_target.window_requests_tx.clone();
+    let draw_tx = event_loop_window_target.draw_tx.clone();
     let window = gtk::ApplicationWindow::builder()
       .application(app)
       .accept_focus(attributes.focused)
@@ -318,14 +321,15 @@ impl Window {
       log::warn!("Fail to send wire up events request: {}", e);
     }
 
-    if let Err(e) = window_requests_tx.send((window_id, WindowRequest::Redraw)) {
-      log::warn!("Fail to send redraw request: {}", e);
+    if let Err(e) = draw_tx.send(window_id) {
+      log::warn!("Failed to send redraw event to event channel: {}", e);
     }
 
     let win = Self {
       window_id,
       window,
       window_requests_tx,
+      draw_tx,
       accel_group,
       menu_bar,
       scale_factor,
@@ -350,11 +354,8 @@ impl Window {
   }
 
   pub fn request_redraw(&self) {
-    if let Err(e) = self
-      .window_requests_tx
-      .send((self.window_id, WindowRequest::Redraw))
-    {
-      log::warn!("Fail to send redraw request: {}", e);
+    if let Err(e) = self.draw_tx.send(self.window_id) {
+      log::warn!("Failed to send redraw event to event channel: {}", e);
     }
   }
 
@@ -820,7 +821,6 @@ pub enum WindowRequest {
   CursorPosition((i32, i32)),
   CursorIgnoreEvents(bool),
   WireUpEvents { transparent: bool },
-  Redraw,
   Menu((Option<MenuItem>, Option<MenuId>)),
   SetMenu((Option<menu::Menu>, AccelGroup, gtk::MenuBar)),
   GlobalHotKey(u16),