Start implementing web-sys backend

Cargo.toml

@@ -20,6 +20,9 @@ libc = "0.2"
 log = "0.4"
 serde = { version = "1", optional = true, features = ["serde_derive"] }
 
+[features]
+web-sys-support = ["web-sys", "wasm-bindgen"]
+
 [dev-dependencies]
 image = "0.21"
 env_logger = "0.5"
@@ -74,6 +77,30 @@ percent-encoding = "1.0"
 [target.'cfg(any(target_os = "linux", target_os = "dragonfly", target_os = "freebsd", target_os = "openbsd", target_os = "netbsd", target_os = "windows"))'.dependencies.parking_lot]
 version = "0.8"
 
+[target.'cfg(target_arch = "wasm32")'.dependencies.web-sys]
+version = "0.3.22"
+optional = true
+features = [
+    'Document',
+    'Event',
+    'EventTarget',
+    'FocusEvent',
+    'HtmlCanvasElement',
+    'KeyboardEvent',
+    'MouseEvent',
+    'PointerEvent',
+    'Window',
+    'WheelEvent'
+]
+
+[target.'cfg(target_arch = "wasm32")'.dependencies.wasm-bindgen]
+version = "0.2.45"
+optional = true
+
+[target.'cfg(target_arch = "wasm32")'.dependencies.stdweb]
+version = "0.4.17"
+optional = true
+
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 stdweb = { path = "../stdweb", optional = true }
 instant = { version = "0.1", features = ["stdweb"] }

examples/window.rs

@@ -1,4 +1,8 @@
 extern crate winit;
+#[cfg(feature = "stdweb")]
+#[macro_use]
+extern crate stdweb;
+#[cfg(feature = "wasm-bindgen")]
 #[macro_use]
 extern crate stdweb;
 
@@ -13,10 +17,10 @@ fn main() {
         .with_title("A fantastic window!")
         .build(&event_loop)
         .unwrap();
-    console!(log, "Built window!");
+    //console!(log, "Built window!");
 
     event_loop.run(|event, _, control_flow| {
-        console!(log, format!("{:?}", event));
+        //console!(log, format!("{:?}", event));
 
         match event {
             Event::WindowEvent {

src/lib.rs

@@ -115,6 +115,10 @@ extern crate smithay_client_toolkit as sctk;
 extern crate stdweb;
 #[cfg(any(target_os = "linux", target_os = "dragonfly", target_os = "freebsd", target_os = "netbsd", target_os = "openbsd"))]
 extern crate calloop;
+#[cfg(feature = "web-sys")]
+extern crate wasm_bindgen;
+#[cfg(feature = "web-sys")]
+extern crate web_sys;
 
 pub mod dpi;
 #[macro_use]

src/platform/mod.rs

@@ -21,5 +21,6 @@ pub mod unix;
 pub mod windows;
 
 pub mod stdweb;
+pub mod web_sys;
 
 pub mod desktop;

src/platform/web_sys.rs

@@ -0,0 +1,7 @@
+#![cfg(feature = "web-sys")]
+
+use web_sys::HtmlCanvasElement;
+
+pub trait WindowExtWebSys {
+    fn canvas(&self) -> HtmlCanvasElement;
+}

src/platform_impl/mod.rs

@@ -1,30 +1,48 @@
 pub use self::platform::*;
 
 #[cfg(target_os = "windows")]
-#[path="windows/mod.rs"]
+#[path = "windows/mod.rs"]
 mod platform;
-#[cfg(any(target_os = "linux", target_os = "dragonfly", target_os = "freebsd", target_os = "netbsd", target_os = "openbsd"))]
-#[path="linux/mod.rs"]
+#[cfg(any(
+    target_os = "linux",
+    target_os = "dragonfly",
+    target_os = "freebsd",
+    target_os = "netbsd",
+    target_os = "openbsd"
+))]
+#[path = "linux/mod.rs"]
 mod platform;
 #[cfg(target_os = "macos")]
-#[path="macos/mod.rs"]
+#[path = "macos/mod.rs"]
 mod platform;
 #[cfg(target_os = "android")]
-#[path="android/mod.rs"]
+#[path = "android/mod.rs"]
 mod platform;
 #[cfg(target_os = "ios")]
-#[path="ios/mod.rs"]
+#[path = "ios/mod.rs"]
 mod platform;
 #[cfg(target_os = "emscripten")]
-#[path="emscripten/mod.rs"]
+#[path = "emscripten/mod.rs"]
 mod platform;
 #[cfg(feature = "stdweb")]
-#[path="stdweb/mod.rs"]
+#[path = "stdweb/mod.rs"]
+mod platform;
+#[cfg(feature = "web-sys")]
+#[path = "web_sys/mod.rs"]
 mod platform;
 
-#[cfg(all(not(target_os = "ios"), not(target_os = "windows"), not(target_os = "linux"),
-  not(target_os = "macos"), not(target_os = "android"), not(target_os = "dragonfly"),
-  not(target_os = "freebsd"), not(target_os = "netbsd"), not(target_os = "openbsd"),
+#[cfg(all(
+    not(target_os = "ios"),
+    not(target_os = "windows"),
+    not(target_os = "linux"),
+    not(target_os = "macos"),
+    not(target_os = "android"),
+    not(target_os = "dragonfly"),
+    not(target_os = "freebsd"),
+    not(target_os = "netbsd"),
+    not(target_os = "openbsd"),
     not(target_os = "emscripten"),
-  not(feature = "stdweb")))]
+    not(feature = "stdweb"),
+    not(feature = "web-sys")
+))]
 compile_error!("The platform you're compiling for is not supported by winit");

src/platform_impl/web_sys/event_loop.rs

@@ -0,0 +1,374 @@
+use super::*;
+
+use dpi::LogicalPosition;
+use event::{
+    DeviceId as RootDI, ElementState, Event, KeyboardInput, MouseScrollDelta, StartCause,
+    TouchPhase, WindowEvent,
+};
+use event_loop::{ControlFlow, EventLoopClosed, EventLoopWindowTarget as RootELW};
+use std::cell::RefCell;
+use std::collections::vec_deque::IntoIter as VecDequeIter;
+use std::collections::VecDeque;
+use std::marker::PhantomData;
+use std::rc::Rc;
+use wasm_bindgen::{prelude::*, JsCast};
+use web_sys::{Document, EventTarget, FocusEvent, HtmlCanvasElement, KeyboardEvent, PointerEvent, WheelEvent};
+use window::WindowId as RootWI;
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct DeviceId(i32);
+
+impl DeviceId {
+    pub unsafe fn dummy() -> Self {
+        DeviceId(0)
+    }
+}
+
+pub struct EventLoop<T: 'static> {
+    elw: RootELW<T>,
+}
+
+pub struct EventLoopWindowTarget<T: 'static> {
+    pub(crate) runner: EventLoopRunnerShared<T>,
+}
+
+impl<T> EventLoopWindowTarget<T> {
+    fn new() -> Self {
+        EventLoopWindowTarget {
+            runner: Rc::new(ELRShared {
+                runner: RefCell::new(None),
+                events: RefCell::new(VecDeque::new()),
+            }),
+        }
+    }
+}
+
+#[derive(Clone)]
+pub struct EventLoopProxy<T> {
+    runner: EventLoopRunnerShared<T>,
+}
+
+impl<T> EventLoopProxy<T> {
+    pub fn send_event(&self, event: T) -> Result<(), EventLoopClosed> {
+        self.runner.send_event(Event::UserEvent(event));
+        Ok(())
+    }
+}
+
+pub type EventLoopRunnerShared<T> = Rc<ELRShared<T>>;
+
+pub struct ELRShared<T> {
+    runner: RefCell<Option<EventLoopRunner<T>>>,
+    events: RefCell<VecDeque<Event<T>>>, // TODO: this may not be necessary?
+}
+
+struct EventLoopRunner<T> {
+    control: ControlFlow,
+    is_busy: bool,
+    event_handler: Box<dyn FnMut(Event<T>, &mut ControlFlow)>,
+}
+
+#[wasm_bindgen]
+extern "C" {
+    #[wasm_bindgen(module = "util.js", js_name = "throwToEscapeEventLoop")]
+    fn throw_to_escape_event_loop();
+}
+
+impl<T> EventLoop<T> {
+    pub fn new() -> Self {
+        EventLoop {
+            elw: RootELW {
+                p: EventLoopWindowTarget::new(),
+                _marker: PhantomData,
+            },
+        }
+    }
+
+    pub fn available_monitors(&self) -> VecDequeIter<MonitorHandle> {
+        VecDeque::new().into_iter()
+    }
+
+    pub fn primary_monitor(&self) -> MonitorHandle {
+        MonitorHandle
+    }
+
+    pub fn run<F>(self, mut event_handler: F) -> !
+    where
+        F: 'static + FnMut(Event<T>, &RootELW<T>, &mut ControlFlow),
+    {
+        let runner = self.elw.p.runner;
+
+        let relw = RootELW {
+            p: EventLoopWindowTarget::new(),
+            _marker: PhantomData,
+        };
+        runner.set_listener(Box::new(move |evt, ctrl| event_handler(evt, &relw, ctrl)));
+
+        let document = &document();
+        add_event(&runner, document, "blur", |elrs, _: FocusEvent| {
+            elrs.send_event(Event::WindowEvent {
+                window_id: RootWI(WindowId),
+                event: WindowEvent::Focused(false),
+            });
+        });
+        add_event(&runner, document, "focus", |elrs, _: FocusEvent| {
+            elrs.send_event(Event::WindowEvent {
+                window_id: RootWI(WindowId),
+                event: WindowEvent::Focused(true),
+            });
+        });
+        add_event(&runner, document, "keydown", |elrs, event: KeyboardEvent| {
+            let key = event.key();
+            let mut characters = key.chars();
+            let first = characters.next();
+            let second = characters.next();
+            if let (Some(key), None) = (first, second) {
+                elrs.send_event(Event::WindowEvent {
+                    window_id: RootWI(WindowId),
+                    event: WindowEvent::ReceivedCharacter(key),
+                });
+            }
+            elrs.send_event(Event::WindowEvent {
+                window_id: RootWI(WindowId),
+                event: WindowEvent::KeyboardInput {
+                    device_id: RootDI(unsafe { DeviceId::dummy() }),
+                    input: KeyboardInput {
+                        scancode: scancode(&event),
+                        state: ElementState::Pressed,
+                        virtual_keycode: button_mapping(&event),
+                        modifiers: keyboard_modifiers_state(&event),
+                    },
+                },
+            });
+        });
+        add_event(&runner, document, "keyup", |elrs, event: KeyboardEvent| {
+            elrs.send_event(Event::WindowEvent {
+                window_id: RootWI(WindowId),
+                event: WindowEvent::KeyboardInput {
+                    device_id: RootDI(unsafe { DeviceId::dummy() }),
+                    input: KeyboardInput {
+                        scancode: scancode(&event),
+                        state: ElementState::Released,
+                        virtual_keycode: button_mapping(&event),
+                        modifiers: keyboard_modifiers_state(&event),
+                    },
+                },
+            });
+        });
+
+        runner.send_event(Event::NewEvents(StartCause::Init));
+
+        // Throw an exception to break out of Rust exceution and use unreachable to tell the
+        // compiler this function won't return, giving it a return type of '!'
+        throw_to_escape_event_loop();
+        unreachable!();
+    }
+
+    pub fn create_proxy(&self) -> EventLoopProxy<T> {
+        EventLoopProxy {
+            runner: self.elw.p.runner.clone(),
+        }
+    }
+
+    pub fn window_target(&self) -> &RootELW<T> {
+        &self.elw
+    }
+}
+
+pub fn register<T: 'static>(elrs: &EventLoopRunnerShared<T>, canvas: &HtmlCanvasElement) {
+    add_event(elrs, canvas, "pointerout", |elrs, event: PointerEvent| {
+        elrs.send_event(Event::WindowEvent {
+            window_id: RootWI(WindowId),
+            event: WindowEvent::CursorLeft {
+                device_id: RootDI(DeviceId(event.pointer_id())),
+            },
+        });
+    });
+    add_event(elrs, canvas, "pointerover", |elrs, event: PointerEvent| {
+        elrs.send_event(Event::WindowEvent {
+            window_id: RootWI(WindowId),
+            event: WindowEvent::CursorEntered {
+                device_id: RootDI(DeviceId(event.pointer_id())),
+            },
+        });
+    });
+    add_event(elrs, canvas, "pointermove", |elrs, event: PointerEvent| {
+        elrs.send_event(Event::WindowEvent {
+            window_id: RootWI(WindowId),
+            event: WindowEvent::CursorMoved {
+                device_id: RootDI(DeviceId(event.pointer_id())),
+                position: LogicalPosition {
+                    x: event.offset_x().into(),
+                    y: event.offset_y().into(),
+                },
+                modifiers: mouse_modifiers_state(&event),
+            },
+        });
+    });
+    add_event(elrs, canvas, "pointerup", |elrs, event: PointerEvent| {
+        elrs.send_event(Event::WindowEvent {
+            window_id: RootWI(WindowId),
+            event: WindowEvent::MouseInput {
+                device_id: RootDI(DeviceId(event.pointer_id())),
+                state: ElementState::Pressed,
+                button: mouse_button(&event),
+                modifiers: mouse_modifiers_state(&event),
+            },
+        });
+    });
+    add_event(elrs, canvas, "pointerdown", |elrs, event: PointerEvent| {
+        elrs.send_event(Event::WindowEvent {
+            window_id: RootWI(WindowId),
+            event: WindowEvent::MouseInput {
+                device_id: RootDI(DeviceId(event.pointer_id())),
+                state: ElementState::Released,
+                button: mouse_button(&event),
+                modifiers: mouse_modifiers_state(&event),
+            },
+        });
+    });
+    add_event(elrs, canvas, "wheel", |elrs, event: WheelEvent| {
+        let x = event.delta_x();
+        let y = event.delta_y();
+        let delta = match event.delta_mode() {
+            WheelEvent::DOM_DELTA_LINE => MouseScrollDelta::LineDelta(x as f32, y as f32),
+            WheelEvent::DOM_DELTA_PIXEL => MouseScrollDelta::PixelDelta(LogicalPosition { x, y }),
+            WheelEvent::DOM_DELTA_PAGE => return,
+        };
+        elrs.send_event(Event::WindowEvent {
+            window_id: RootWI(WindowId),
+            event: WindowEvent::MouseWheel {
+                device_id: RootDI(DeviceId(0)),
+                delta,
+                phase: TouchPhase::Moved,
+                modifiers: mouse_modifiers_state(&event),
+            },
+        });
+    });
+}
+
+fn add_event<T: 'static, E, F>(
+    elrs: &EventLoopRunnerShared<T>,
+    target: &EventTarget,
+    event: &str,
+    mut handler: F,
+) where
+    E: AsRef<web_sys::Event> + wasm_bindgen::convert::FromWasmAbi + 'static,
+    F: FnMut(&EventLoopRunnerShared<T>, E) + 'static,
+{
+    let elrs = elrs.clone();
+
+    target.add_event_listener_with_callback(event, Closure::wrap(Box::new(move |event: E| {
+        // Don't capture the event if the events loop has been destroyed
+        match &*elrs.runner.borrow() {
+            Some(ref runner) if runner.control == ControlFlow::Exit => return,
+            _ => (),
+        }
+
+        let event_ref = event.as_ref();
+        event_ref.prevent_default();
+        event_ref.stop_propagation();
+        event_ref.cancel_bubble();
+
+        handler(&elrs, event);
+    }) as Box<FnMut(E)>).as_ref().unchecked_ref());
+}
+
+impl<T> ELRShared<T> {
+    // Set the event callback to use for the event loop runner
+    // This the event callback is a fairly thin layer over the user-provided callback that closes
+    // over a RootEventLoopWindowTarget reference
+    fn set_listener(&self, event_handler: Box<dyn FnMut(Event<T>, &mut ControlFlow)>) {
+        *self.runner.borrow_mut() = Some(EventLoopRunner {
+            control: ControlFlow::Poll,
+            is_busy: false,
+            event_handler,
+        });
+    }
+
+    // Add an event to the event loop runner
+    //
+    // It will determine if the event should be immediately sent to the user or buffered for later
+    pub fn send_event(&self, event: Event<T>) {
+        // If the event loop is closed, it should discard any new events
+        if self.closed() {
+            return;
+        }
+
+        let start_cause = StartCause::Poll; // TODO: determine start cause
+
+        // Determine if event handling is in process, and then release the borrow on the runner
+        let is_busy = if let Some(ref runner) = *self.runner.borrow() {
+            runner.is_busy
+        } else {
+            true // If there is no event runner yet, then there's no point in processing events
+        };
+
+        if is_busy {
+            self.events.borrow_mut().push_back(event);
+        } else {
+            // Handle starting a new batch of events
+            //
+            // The user is informed via Event::NewEvents that there is a batch of events to process
+            // However, there is only one of these per batch of events
+            self.handle_event(Event::NewEvents(start_cause));
+            self.handle_event(event);
+            self.handle_event(Event::EventsCleared);
+
+            // If the event loop is closed, it has been closed this iteration and now the closing
+            // event should be emitted
+            if self.closed() {
+                self.handle_event(Event::LoopDestroyed);
+            }
+        }
+    }
+
+    // Check if the event loop is currntly closed
+    fn closed(&self) -> bool {
+        match *self.runner.borrow() {
+            Some(ref runner) => runner.control == ControlFlow::Exit,
+            None => false, // If the event loop is None, it has not been intialised yet, so it cannot be closed
+        }
+    }
+
+    // handle_event takes in events and either queues them or applies a callback
+    //
+    // It should only ever be called from send_event
+    fn handle_event(&self, event: Event<T>) {
+        let closed = self.closed();
+
+        match *self.runner.borrow_mut() {
+            Some(ref mut runner) => {
+                // An event is being processed, so the runner should be marked busy
+                runner.is_busy = true;
+
+                // TODO: bracket this in control flow events?
+                (runner.event_handler)(event, &mut runner.control);
+
+                // Maintain closed state, even if the callback changes it
+                if closed {
+                    runner.control = ControlFlow::Exit;
+                }
+
+                // An event is no longer being processed
+                runner.is_busy = false;
+            }
+            // If an event is being handled without a runner somehow, add it to the event queue so
+            // it will eventually be processed
+            _ => self.events.borrow_mut().push_back(event),
+        }
+
+        // Don't take events out of the queue if the loop is closed or the runner doesn't exist
+        // If the runner doesn't exist and this method recurses, it will recurse infinitely
+        if !closed && self.runner.borrow().is_some() {
+            // Take an event out of the queue and handle it
+            if let Some(event) = self.events.borrow_mut().pop_front() {
+                self.handle_event(event);
+            }
+        }
+    }
+}
+
+fn document() -> Document {
+    web_sys::window().unwrap().document().unwrap()
+}

src/platform_impl/web_sys/events.rs

@@ -0,0 +1 @@
+

src/platform_impl/web_sys/mod.rs

@@ -0,0 +1,24 @@
+use std::fmt;
+
+mod event_loop;
+mod events;
+mod window;
+
+pub use self::event_loop::{
+    register, DeviceId, EventLoop, EventLoopProxy, EventLoopRunnerShared, EventLoopWindowTarget,
+};
+pub use self::events::{
+    button_mapping, keyboard_modifiers_state, mouse_button, mouse_modifiers_state, scancode,
+};
+pub use self::window::{MonitorHandle, PlatformSpecificWindowBuilderAttributes, Window, WindowId};
+
+// TODO: unify with stdweb impl.
+
+#[derive(Debug)]
+pub struct OsError(String);
+
+impl fmt::Display for OsError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}

src/platform_impl/web_sys/util.js

@@ -0,0 +1,3 @@
+function throwToEscapeEventLoop() {
+    throw "Using exceptions for control flow, don't mind me. This isn't actually an error!";
+}

src/platform_impl/web_sys/window.rs

@@ -0,0 +1 @@
+