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Implement revamped RedrawRequested on Windows (#1050)

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* Move event loop runner to runner module

* Implement new redraw API
This commit is contained in:
Osspial 2019-08-26 22:05:42 -04:00
parent 0c151f9fb3
commit 8eb7853a1a
4 changed files with 466 additions and 428 deletions
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5
examples/window.rs
View file

@ -20,7 +20,10 @@ fn main() {
event: WindowEvent::CloseRequested,
window_id,
} if window_id == window.id() => *control_flow = ControlFlow::Exit,
_ => *control_flow = ControlFlow::Wait,
Event::MainEventsCleared => {
window.request_redraw();
}
_ => *control_flow = ControlFlow::Poll,
}
});
}

453
src/platform_impl/windows/event_loop.rs
View file

@ -13,16 +13,14 @@
//! The closure passed to the `execute_in_thread` method takes an `Inserter` that you can use to
//! add a `WindowState` entry to a list of window to be used by the callback.
mod runner;
use parking_lot::Mutex;
use std::{
any::Any,
cell::RefCell,
collections::VecDeque,
marker::PhantomData,
mem, panic, ptr,
rc::Rc,
sync::{
atomic::{AtomicBool, Ordering},
mpsc::{self, Receiver, Sender},
Arc,
},
@ -44,9 +42,10 @@ use winapi::{
},
};
use self::runner::{ELRShared, EventLoopRunnerShared};
use crate::{
dpi::{LogicalPosition, LogicalSize, PhysicalSize},
event::{DeviceEvent, Event, Force, KeyboardInput, StartCause, Touch, TouchPhase, WindowEvent},
event::{DeviceEvent, Event, Force, KeyboardInput, Touch, TouchPhase, WindowEvent},
event_loop::{ControlFlow, EventLoopClosed, EventLoopWindowTarget as RootELW},
platform_impl::platform::{
dpi::{
@ -127,7 +126,6 @@ pub struct EventLoop<T: 'static> {
pub struct EventLoopWindowTarget<T> {
thread_id: DWORD,
trigger_newevents_on_redraw: Arc<AtomicBool>,
thread_msg_target: HWND,
pub(crate) runner_shared: EventLoopRunnerShared<T>,
}
@ -167,10 +165,7 @@ impl<T: 'static> EventLoop<T> {
pub fn new_dpi_unaware_any_thread() -> EventLoop<T> {
let thread_id = unsafe { processthreadsapi::GetCurrentThreadId() };
let runner_shared = Rc::new(ELRShared {
runner: RefCell::new(None),
buffer: RefCell::new(VecDeque::new()),
});
let runner_shared = Rc::new(ELRShared::new());
let (thread_msg_target, thread_msg_sender) =
thread_event_target_window(runner_shared.clone());
@ -179,7 +174,6 @@ impl<T: 'static> EventLoop<T> {
window_target: RootELW {
p: EventLoopWindowTarget {
thread_id,
trigger_newevents_on_redraw: Arc::new(AtomicBool::new(true)),
thread_msg_target,
runner_shared,
},
@ -206,44 +200,23 @@ impl<T: 'static> EventLoop<T> {
{
let event_loop_windows_ref = &self.window_target;
let mut runner = unsafe {
EventLoopRunner::new(self, move |event, control_flow| {
event_handler(event, event_loop_windows_ref, control_flow)
})
};
{
let runner_shared = self.window_target.p.runner_shared.clone();
let mut runner_ref = runner_shared.runner.borrow_mut();
loop {
let event = runner_shared.buffer.borrow_mut().pop_front();
match event {
Some(e) => {
runner.process_event(e);
}
None => break,
}
}
*runner_ref = Some(runner);
unsafe {
self.window_target
.p
.runner_shared
.set_runner(self, move |event, control_flow| {
event_handler(event, event_loop_windows_ref, control_flow)
})
}
macro_rules! runner {
() => {
self.window_target
.p
.runner_shared
.runner
.borrow_mut()
.as_mut()
.unwrap()
};
}
let runner = &self.window_target.p.runner_shared;
unsafe {
let mut msg = mem::zeroed();
let mut msg_unprocessed = false;
'main: loop {
runner!().new_events();
runner.new_events();
loop {
if !msg_unprocessed {
if 0 == winuser::PeekMessageW(&mut msg, ptr::null_mut(), 0, 0, 1) {
@ -255,13 +228,14 @@ impl<T: 'static> EventLoop<T> {
msg_unprocessed = false;
}
runner!().events_cleared();
if let Some(payload) = runner!().panic_error.take() {
runner.events_cleared();
if let Err(payload) = runner.take_panic_error() {
runner.destroy_runner();
panic::resume_unwind(payload);
}
if !msg_unprocessed {
let control_flow = runner!().control_flow;
let control_flow = runner.control_flow();
match control_flow {
ControlFlow::Exit => break 'main,
ControlFlow::Wait => {
@ -279,8 +253,10 @@ impl<T: 'static> EventLoop<T> {
}
}
runner!().call_event_handler(Event::LoopDestroyed);
*self.window_target.p.runner_shared.runner.borrow_mut() = None;
unsafe {
runner.call_event_handler(Event::LoopDestroyed);
}
runner.destroy_runner();
}
pub fn create_proxy(&self) -> EventLoopProxy<T> {
@ -296,7 +272,6 @@ impl<T> EventLoopWindowTarget<T> {
pub(crate) fn create_thread_executor(&self) -> EventLoopThreadExecutor {
EventLoopThreadExecutor {
thread_id: self.thread_id,
trigger_newevents_on_redraw: self.trigger_newevents_on_redraw.clone(),
target_window: self.thread_msg_target,
}
}
@ -317,291 +292,6 @@ fn main_thread_id() -> DWORD {
unsafe { MAIN_THREAD_ID }
}
pub(crate) type EventLoopRunnerShared<T> = Rc<ELRShared<T>>;
pub(crate) struct ELRShared<T> {
runner: RefCell<Option<EventLoopRunner<T>>>,
buffer: RefCell<VecDeque<Event<T>>>,
}
pub(crate) struct EventLoopRunner<T> {
trigger_newevents_on_redraw: Arc<AtomicBool>,
control_flow: ControlFlow,
runner_state: RunnerState,
modal_redraw_window: HWND,
in_modal_loop: bool,
in_repaint: bool,
event_handler: Box<dyn FnMut(Event<T>, &mut ControlFlow)>,
panic_error: Option<PanicError>,
}
type PanicError = Box<dyn Any + Send + 'static>;
impl<T> ELRShared<T> {
pub(crate) unsafe fn send_event(&self, event: Event<T>) {
if let Ok(mut runner_ref) = self.runner.try_borrow_mut() {
if let Some(ref mut runner) = *runner_ref {
runner.process_event(event);
// Dispatch any events that were buffered during the call to `process_event`.
loop {
// We do this instead of using a `while let` loop because if we use a `while let`
// loop the reference returned `borrow_mut()` doesn't get dropped until the end
// of the loop's body and attempts to add events to the event buffer while in
// `process_event` will fail.
let buffered_event_opt = self.buffer.borrow_mut().pop_front();
match buffered_event_opt {
Some(event) => runner.process_event(event),
None => break,
}
}
return;
}
}
// If the runner is already borrowed, we're in the middle of an event loop invocation. Add
// the event to a buffer to be processed later.
self.buffer.borrow_mut().push_back(event)
}
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum RunnerState {
/// The event loop has just been created, and an `Init` event must be sent.
New,
/// The event loop is idling, and began idling at the given instant.
Idle(Instant),
/// The event loop has received a signal from the OS that the loop may resume, but no winit
/// events have been generated yet. We're waiting for an event to be processed or the events
/// to be marked as cleared to send `NewEvents`, depending on the current `ControlFlow`.
DeferredNewEvents(Instant),
/// The event loop is handling the OS's events and sending them to the user's callback.
/// `NewEvents` has been sent, and `EventsCleared` hasn't.
HandlingEvents,
}
impl<T> EventLoopRunner<T> {
unsafe fn new<F>(event_loop: &EventLoop<T>, f: F) -> EventLoopRunner<T>
where
F: FnMut(Event<T>, &mut ControlFlow),
{
EventLoopRunner {
trigger_newevents_on_redraw: event_loop
.window_target
.p
.trigger_newevents_on_redraw
.clone(),
control_flow: ControlFlow::default(),
runner_state: RunnerState::New,
in_modal_loop: false,
in_repaint: false,
modal_redraw_window: event_loop.window_target.p.thread_msg_target,
event_handler: mem::transmute::<
Box<dyn FnMut(Event<T>, &mut ControlFlow)>,
Box<dyn FnMut(Event<T>, &mut ControlFlow)>,
>(Box::new(f)),
panic_error: None,
}
}
fn new_events(&mut self) {
self.runner_state = match self.runner_state {
// If we're already handling events or have deferred `NewEvents`, we don't need to do
// do any processing.
RunnerState::HandlingEvents | RunnerState::DeferredNewEvents(..) => self.runner_state,
// Send the `Init` `NewEvents` and immediately move into event processing.
RunnerState::New => {
self.call_event_handler(Event::NewEvents(StartCause::Init));
RunnerState::HandlingEvents
}
// When `NewEvents` gets sent after an idle depends on the control flow...
RunnerState::Idle(wait_start) => {
match self.control_flow {
// If we're polling, send `NewEvents` and immediately move into event processing.
ControlFlow::Poll => {
self.call_event_handler(Event::NewEvents(StartCause::Poll));
RunnerState::HandlingEvents
},
// If the user was waiting until a specific time, the `NewEvents` call gets sent
// at varying times depending on the current time.
ControlFlow::WaitUntil(resume_time) => {
match Instant::now() >= resume_time {
// If the current time is later than the requested resume time, we can tell the
// user that the resume time has been reached with `NewEvents` and immdiately move
// into event processing.
true => {
self.call_event_handler(Event::NewEvents(StartCause::ResumeTimeReached {
start: wait_start,
requested_resume: resume_time,
}));
RunnerState::HandlingEvents
},
// However, if the current time is EARLIER than the requested resume time, we
// don't want to send the `WaitCancelled` event until we know an event is being
// sent. Defer.
false => RunnerState::DeferredNewEvents(wait_start)
}
},
// If we're waiting, `NewEvents` doesn't get sent until winit gets an event, so
// we defer.
ControlFlow::Wait |
// `Exit` shouldn't really ever get sent here, but if it does do something somewhat sane.
ControlFlow::Exit => RunnerState::DeferredNewEvents(wait_start),
}
}
};
}
fn process_event(&mut self, event: Event<T>) {
// If we're in the modal loop, we need to have some mechanism for finding when the event
// queue has been cleared so we can call `events_cleared`. Windows doesn't give any utilities
// for doing this, but it DOES guarantee that WM_PAINT will only occur after input events have
// been processed. So, we send WM_PAINT to a dummy window which calls `events_cleared` when
// the events queue has been emptied.
if self.in_modal_loop {
unsafe {
winuser::RedrawWindow(
self.modal_redraw_window,
ptr::null(),
ptr::null_mut(),
winuser::RDW_INTERNALPAINT,
);
}
}
// If new event processing has to be done (i.e. call NewEvents or defer), do it. If we're
// already in processing nothing happens with this call.
self.new_events();
// Now that an event has been received, we have to send any `NewEvents` calls that were
// deferred.
if let RunnerState::DeferredNewEvents(wait_start) = self.runner_state {
match self.control_flow {
ControlFlow::Exit | ControlFlow::Wait => {
self.call_event_handler(Event::NewEvents(StartCause::WaitCancelled {
start: wait_start,
requested_resume: None,
}))
}
ControlFlow::WaitUntil(resume_time) => {
let start_cause = match Instant::now() >= resume_time {
// If the current time is later than the requested resume time, the resume time
// has been reached.
true => StartCause::ResumeTimeReached {
start: wait_start,
requested_resume: resume_time,
},
// Otherwise, the requested resume time HASN'T been reached and we send a WaitCancelled.
false => StartCause::WaitCancelled {
start: wait_start,
requested_resume: Some(resume_time),
},
};
self.call_event_handler(Event::NewEvents(start_cause));
}
// This can be reached if the control flow is changed to poll during a `RedrawRequested`
// that was sent after `EventsCleared`.
ControlFlow::Poll => self.call_event_handler(Event::NewEvents(StartCause::Poll)),
}
}
self.runner_state = RunnerState::HandlingEvents;
match (self.in_repaint, &event) {
(
true,
Event::WindowEvent {
event: WindowEvent::RedrawRequested,
..
},
)
| (false, _) => self.call_event_handler(event),
(true, _) => {
self.events_cleared();
self.new_events();
self.process_event(event);
}
}
}
fn events_cleared(&mut self) {
self.in_repaint = false;
match self.runner_state {
// If we were handling events, send the EventsCleared message.
RunnerState::HandlingEvents => {
self.call_event_handler(Event::EventsCleared);
self.runner_state = RunnerState::Idle(Instant::now());
}
// If we *weren't* handling events, we don't have to do anything.
RunnerState::New | RunnerState::Idle(..) => (),
// Some control flows require a NewEvents call even if no events were received. This
// branch handles those.
RunnerState::DeferredNewEvents(wait_start) => {
match self.control_flow {
// If we had deferred a Poll, send the Poll NewEvents and EventsCleared.
ControlFlow::Poll => {
self.call_event_handler(Event::NewEvents(StartCause::Poll));
self.call_event_handler(Event::EventsCleared);
}
// If we had deferred a WaitUntil and the resume time has since been reached,
// send the resume notification and EventsCleared event.
ControlFlow::WaitUntil(resume_time) => {
if Instant::now() >= resume_time {
self.call_event_handler(Event::NewEvents(
StartCause::ResumeTimeReached {
start: wait_start,
requested_resume: resume_time,
},
));
self.call_event_handler(Event::EventsCleared);
}
}
// If we deferred a wait and no events were received, the user doesn't have to
// get an event.
ControlFlow::Wait | ControlFlow::Exit => (),
}
// Mark that we've entered an idle state.
self.runner_state = RunnerState::Idle(wait_start)
}
}
}
fn call_event_handler(&mut self, event: Event<T>) {
match event {
Event::NewEvents(_) => self
.trigger_newevents_on_redraw
.store(true, Ordering::Relaxed),
Event::EventsCleared => self
.trigger_newevents_on_redraw
.store(false, Ordering::Relaxed),
Event::WindowEvent {
event: WindowEvent::RedrawRequested,
..
} => self.in_repaint = true,
_ => (),
}
if self.panic_error.is_none() {
let EventLoopRunner {
ref mut panic_error,
ref mut event_handler,
ref mut control_flow,
..
} = self;
*panic_error = panic::catch_unwind(panic::AssertUnwindSafe(|| {
if *control_flow != ControlFlow::Exit {
(*event_handler)(event, control_flow);
} else {
(*event_handler)(event, &mut ControlFlow::Exit);
}
}))
.err();
}
}
}
// Returns true if the wait time was reached, and false if a message must be processed.
unsafe fn wait_until_time_or_msg(wait_until: Instant) -> bool {
let mut msg = mem::zeroed();
@ -667,7 +357,6 @@ impl<T> Drop for EventLoop<T> {
pub(crate) struct EventLoopThreadExecutor {
thread_id: DWORD,
trigger_newevents_on_redraw: Arc<AtomicBool>,
target_window: HWND,
}
@ -681,10 +370,6 @@ impl EventLoopThreadExecutor {
self.thread_id == cur_thread_id
}
pub(super) fn trigger_newevents_on_redraw(&self) -> bool {
!self.in_event_loop_thread() || self.trigger_newevents_on_redraw.load(Ordering::Relaxed)
}
/// Executes a function in the event loop thread. If we're already in the event loop thread,
/// we just call the function directly.
///
@ -784,12 +469,6 @@ lazy_static! {
winuser::RegisterWindowMessageA("Winit::InitialDpiMsg\0".as_ptr() as LPCSTR)
}
};
// Message sent by a `Window` if it's requesting a redraw without sending a NewEvents.
pub static ref REQUEST_REDRAW_NO_NEWEVENTS_MSG_ID: u32 = {
unsafe {
winuser::RegisterWindowMessageA("Winit::RequestRedrawNoNewevents\0".as_ptr() as LPCSTR)
}
};
// WPARAM is a bool specifying the `WindowFlags::MARKER_RETAIN_STATE_ON_SIZE` flag. See the
// documentation in the `window_state` module for more information.
pub static ref SET_RETAIN_STATE_ON_SIZE_MSG_ID: u32 = unsafe {
@ -922,21 +601,15 @@ unsafe extern "system" fn public_window_callback<T>(
_: UINT_PTR,
subclass_input_ptr: DWORD_PTR,
) -> LRESULT {
let subclass_input = &mut *(subclass_input_ptr as *mut SubclassInput<T>);
let subclass_input = &*(subclass_input_ptr as *const SubclassInput<T>);
match msg {
winuser::WM_ENTERSIZEMOVE => {
let mut runner = subclass_input.event_loop_runner.runner.borrow_mut();
if let Some(ref mut runner) = *runner {
runner.in_modal_loop = true;
}
subclass_input.event_loop_runner.set_modal_loop(true);
0
}
winuser::WM_EXITSIZEMOVE => {
let mut runner = subclass_input.event_loop_runner.runner.borrow_mut();
if let Some(ref mut runner) = *runner {
runner.in_modal_loop = false;
}
subclass_input.event_loop_runner.set_modal_loop(false);
0
}
winuser::WM_NCCREATE => {
@ -975,48 +648,13 @@ unsafe extern "system" fn public_window_callback<T>(
event: Destroyed,
});
Box::from_raw(subclass_input);
drop(subclass_input);
Box::from_raw(subclass_input_ptr as *mut SubclassInput<T>);
0
}
_ if msg == *REQUEST_REDRAW_NO_NEWEVENTS_MSG_ID => {
use crate::event::WindowEvent::RedrawRequested;
let mut runner = subclass_input.event_loop_runner.runner.borrow_mut();
subclass_input.window_state.lock().queued_out_of_band_redraw = false;
if let Some(ref mut runner) = *runner {
// This check makes sure that calls to `request_redraw()` during `EventsCleared`
// handling dispatch `RedrawRequested` immediately after `EventsCleared`, without
// spinning up a new event loop iteration. We do this because that's what the API
// says to do.
let runner_state = runner.runner_state;
let mut request_redraw = || {
runner.call_event_handler(Event::WindowEvent {
window_id: RootWindowId(WindowId(window)),
event: RedrawRequested,
});
};
match runner_state {
RunnerState::Idle(..) | RunnerState::DeferredNewEvents(..) => request_redraw(),
RunnerState::HandlingEvents => {
winuser::RedrawWindow(
window,
ptr::null(),
ptr::null_mut(),
winuser::RDW_INTERNALPAINT,
);
}
_ => (),
}
}
0
}
winuser::WM_PAINT => {
use crate::event::WindowEvent::RedrawRequested;
subclass_input.send_event(Event::WindowEvent {
window_id: RootWindowId(WindowId(window)),
event: RedrawRequested,
});
subclass_input.send_event(Event::RedrawRequested(RootWindowId(WindowId(window))));
commctrl::DefSubclassProc(window, msg, wparam, lparam)
}
@ -1984,14 +1622,7 @@ unsafe extern "system" fn thread_event_target_callback<T>(
winuser::RDW_INTERNALPAINT,
);
};
let in_modal_loop = {
let runner = subclass_input.event_loop_runner.runner.borrow_mut();
if let Some(ref runner) = *runner {
runner.in_modal_loop
} else {
false
}
};
let in_modal_loop = subclass_input.event_loop_runner.in_modal_loop();
if in_modal_loop {
let mut msg = mem::zeroed();
loop {
@ -2019,21 +1650,19 @@ unsafe extern "system" fn thread_event_target_callback<T>(
}
}
let mut runner = subclass_input.event_loop_runner.runner.borrow_mut();
if let Some(ref mut runner) = *runner {
runner.events_cleared();
match runner.control_flow {
// Waiting is handled by the modal loop.
ControlFlow::Exit | ControlFlow::Wait => runner.new_events(),
ControlFlow::WaitUntil(resume_time) => {
wait_until_time_or_msg(resume_time);
runner.new_events();
queue_call_again();
}
ControlFlow::Poll => {
runner.new_events();
queue_call_again();
}
let runner = &subclass_input.event_loop_runner;
runner.events_cleared();
match runner.control_flow() {
// Waiting is handled by the modal loop.
ControlFlow::Exit | ControlFlow::Wait => runner.new_events(),
ControlFlow::WaitUntil(resume_time) => {
wait_until_time_or_msg(resume_time);
runner.new_events();
queue_call_again();
}
ControlFlow::Poll => {
runner.new_events();
queue_call_again();
}
}
}

415
src/platform_impl/windows/event_loop/runner.rs Normal file
View file

@ -0,0 +1,415 @@
use std::{
any::Any,
cell::RefCell,
collections::VecDeque,
mem, panic, ptr,
rc::Rc,
time::Instant,
};
use winapi::{
shared::{
windef::HWND,
},
um::winuser,
};
use crate::{
event::{Event, StartCause},
event_loop::ControlFlow,
platform_impl::platform::{
event_loop::EventLoop,
},
window::WindowId,
};
pub(crate) type EventLoopRunnerShared<T> = Rc<ELRShared<T>>;
pub(crate) struct ELRShared<T> {
runner: RefCell<Option<EventLoopRunner<T>>>,
buffer: RefCell<VecDeque<Event<T>>>,
redraw_buffer: Rc<RefCell<VecDeque<WindowId>>>,
}
struct EventLoopRunner<T> {
control_flow: ControlFlow,
runner_state: RunnerState,
modal_redraw_window: HWND,
in_modal_loop: bool,
event_handler: Box<dyn FnMut(Event<T>, &mut ControlFlow)>,
panic_error: Option<PanicError>,
redraw_buffer: Rc<RefCell<VecDeque<WindowId>>>,
}
pub type PanicError = Box<dyn Any + Send + 'static>;
impl<T> ELRShared<T> {
pub(crate) fn new() -> ELRShared<T> {
ELRShared {
runner: RefCell::new(None),
buffer: RefCell::new(VecDeque::new()),
redraw_buffer: Default::default(),
}
}
pub(crate) unsafe fn set_runner<F>(&self, event_loop: &EventLoop<T>, f: F)
where
F: FnMut(Event<T>, &mut ControlFlow),
{
let mut runner = EventLoopRunner::new(event_loop, self.redraw_buffer.clone(), f);
{
let mut runner_ref = self.runner.borrow_mut();
loop {
let event = self.buffer.borrow_mut().pop_front();
match event {
Some(e) => {
runner.process_event(e);
}
None => break,
}
}
*runner_ref = Some(runner);
}
}
pub(crate) fn destroy_runner(&self) {
*self.runner.borrow_mut() = None;
}
pub(crate) fn new_events(&self) {
let mut runner_ref = self.runner.borrow_mut();
if let Some(ref mut runner) = *runner_ref {
runner.new_events();
}
}
pub(crate) unsafe fn send_event(&self, event: Event<T>) {
if let Ok(mut runner_ref) = self.runner.try_borrow_mut() {
if let Some(ref mut runner) = *runner_ref {
runner.process_event(event);
// Dispatch any events that were buffered during the call to `process_event`.
loop {
// We do this instead of using a `while let` loop because if we use a `while let`
// loop the reference returned `borrow_mut()` doesn't get dropped until the end
// of the loop's body and attempts to add events to the event buffer while in
// `process_event` will fail.
let buffered_event_opt = self.buffer.borrow_mut().pop_front();
match buffered_event_opt {
Some(event) => runner.process_event(event),
None => break,
}
}
return;
}
}
// If the runner is already borrowed, we're in the middle of an event loop invocation. Add
// the event to a buffer to be processed later.
self.buffer_event(event);
}
pub(crate) unsafe fn call_event_handler(&self, event: Event<T>) {
if let Ok(mut runner_ref) = self.runner.try_borrow_mut() {
if let Some(ref mut runner) = *runner_ref {
runner.call_event_handler(event);
return;
}
}
}
pub(crate) fn events_cleared(&self) {
let mut runner_ref = self.runner.borrow_mut();
if let Some(ref mut runner) = *runner_ref {
runner.events_cleared();
}
}
pub(crate) fn take_panic_error(&self) -> Result<(), PanicError> {
let mut runner_ref = self.runner.borrow_mut();
if let Some(ref mut runner) = *runner_ref {
runner.take_panic_error()
} else {
Ok(())
}
}
pub(crate) fn set_modal_loop(&self, in_modal_loop: bool) {
let mut runner_ref = self.runner.borrow_mut();
if let Some(ref mut runner) = *runner_ref {
runner.in_modal_loop = in_modal_loop;
}
}
pub(crate) fn in_modal_loop(&self) -> bool {
let runner = self.runner.borrow();
if let Some(ref runner) = *runner {
runner.in_modal_loop
} else {
false
}
}
pub fn control_flow(&self) -> ControlFlow {
let runner_ref = self.runner.borrow();
if let Some(ref runner) = *runner_ref {
runner.control_flow
} else {
ControlFlow::Exit
}
}
fn buffer_event(&self, event: Event<T>) {
match event {
Event::RedrawRequested(window_id) => self.redraw_buffer.borrow_mut().push_back(window_id),
_ => self.buffer.borrow_mut().push_back(event),
}
}
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum RunnerState {
/// The event loop has just been created, and an `Init` event must be sent.
New,
/// The event loop is idling, and began idling at the given instant.
Idle(Instant),
/// The event loop has received a signal from the OS that the loop may resume, but no winit
/// events have been generated yet. We're waiting for an event to be processed or the events
/// to be marked as cleared to send `NewEvents`, depending on the current `ControlFlow`.
DeferredNewEvents(Instant),
/// The event loop is handling the OS's events and sending them to the user's callback.
/// `NewEvents` has been sent, and `EventsCleared` hasn't.
HandlingEvents,
HandlingRedraw,
}
impl<T> EventLoopRunner<T> {
unsafe fn new<F>(event_loop: &EventLoop<T>, redraw_buffer: Rc<RefCell<VecDeque<WindowId>>>, f: F) -> EventLoopRunner<T>
where
F: FnMut(Event<T>, &mut ControlFlow),
{
EventLoopRunner {
control_flow: ControlFlow::default(),
runner_state: RunnerState::New,
in_modal_loop: false,
modal_redraw_window: event_loop.window_target.p.thread_msg_target,
event_handler: mem::transmute::<
Box<dyn FnMut(Event<T>, &mut ControlFlow)>,
Box<dyn FnMut(Event<T>, &mut ControlFlow)>,
>(Box::new(f)),
panic_error: None,
redraw_buffer,
}
}
fn take_panic_error(&mut self) -> Result<(), PanicError> {
match self.panic_error.take() {
Some(err) => Err(err),
None => Ok(()),
}
}
fn new_events(&mut self) {
self.runner_state = match self.runner_state {
// If we're already handling events or have deferred `NewEvents`, we don't need to do
// do any processing.
RunnerState::HandlingEvents | RunnerState::HandlingRedraw | RunnerState::DeferredNewEvents(..) => self.runner_state,
// Send the `Init` `NewEvents` and immediately move into event processing.
RunnerState::New => {
self.call_event_handler(Event::NewEvents(StartCause::Init));
RunnerState::HandlingEvents
}
// When `NewEvents` gets sent after an idle depends on the control flow...
RunnerState::Idle(wait_start) => {
match self.control_flow {
// If we're polling, send `NewEvents` and immediately move into event processing.
ControlFlow::Poll => {
self.call_event_handler(Event::NewEvents(StartCause::Poll));
RunnerState::HandlingEvents
},
// If the user was waiting until a specific time, the `NewEvents` call gets sent
// at varying times depending on the current time.
ControlFlow::WaitUntil(resume_time) => {
match Instant::now() >= resume_time {
// If the current time is later than the requested resume time, we can tell the
// user that the resume time has been reached with `NewEvents` and immdiately move
// into event processing.
true => {
self.call_event_handler(Event::NewEvents(StartCause::ResumeTimeReached {
start: wait_start,
requested_resume: resume_time,
}));
RunnerState::HandlingEvents
},
// However, if the current time is EARLIER than the requested resume time, we
// don't want to send the `WaitCancelled` event until we know an event is being
// sent. Defer.
false => RunnerState::DeferredNewEvents(wait_start)
}
},
// If we're waiting, `NewEvents` doesn't get sent until winit gets an event, so
// we defer.
ControlFlow::Wait |
// `Exit` shouldn't really ever get sent here, but if it does do something somewhat sane.
ControlFlow::Exit => RunnerState::DeferredNewEvents(wait_start),
}
}
};
}
fn process_event(&mut self, event: Event<T>) {
// If we're in the modal loop, we need to have some mechanism for finding when the event
// queue has been cleared so we can call `events_cleared`. Windows doesn't give any utilities
// for doing this, but it DOES guarantee that WM_PAINT will only occur after input events have
// been processed. So, we send WM_PAINT to a dummy window which calls `events_cleared` when
// the events queue has been emptied.
if self.in_modal_loop {
unsafe {
winuser::RedrawWindow(
self.modal_redraw_window,
ptr::null(),
ptr::null_mut(),
winuser::RDW_INTERNALPAINT,
);
}
}
// If new event processing has to be done (i.e. call NewEvents or defer), do it. If we're
// already in processing nothing happens with this call.
self.new_events();
// Now that an event has been received, we have to send any `NewEvents` calls that were
// deferred.
if let RunnerState::DeferredNewEvents(wait_start) = self.runner_state {
match self.control_flow {
ControlFlow::Exit | ControlFlow::Wait => {
self.call_event_handler(Event::NewEvents(StartCause::WaitCancelled {
start: wait_start,
requested_resume: None,
}))
}
ControlFlow::WaitUntil(resume_time) => {
let start_cause = match Instant::now() >= resume_time {
// If the current time is later than the requested resume time, the resume time
// has been reached.
true => StartCause::ResumeTimeReached {
start: wait_start,
requested_resume: resume_time,
},
// Otherwise, the requested resume time HASN'T been reached and we send a WaitCancelled.
false => StartCause::WaitCancelled {
start: wait_start,
requested_resume: Some(resume_time),
},
};
self.call_event_handler(Event::NewEvents(start_cause));
}
// This can be reached if the control flow is changed to poll during a `RedrawRequested`
// that was sent after `EventsCleared`.
ControlFlow::Poll => self.call_event_handler(Event::NewEvents(StartCause::Poll)),
}
}
match (self.runner_state, &event) {
(RunnerState::HandlingRedraw, Event::RedrawRequested(_)) => self.call_event_handler(event),
(_, Event::RedrawRequested(_)) => {
self.call_event_handler(Event::MainEventsCleared);
self.runner_state = RunnerState::HandlingRedraw;
self.call_event_handler(event);
},
(RunnerState::HandlingRedraw, _) => {
warn!("Non-redraw event dispatched durning redraw phase");
self.events_cleared();
self.new_events();
self.call_event_handler(event);
}
(_, _) => {
self.runner_state = RunnerState::HandlingEvents;
self.call_event_handler(event);
}
}
}
fn flush_redraws(&mut self) {
loop {
let redraw_window_opt = self.redraw_buffer.borrow_mut().pop_front();
match redraw_window_opt {
Some(window_id) => self.process_event(Event::RedrawRequested(window_id)),
None => break,
}
}
}
fn events_cleared(&mut self) {
match self.runner_state {
// If we were handling events, send the EventsCleared message.
RunnerState::HandlingEvents => {
self.call_event_handler(Event::MainEventsCleared);
self.flush_redraws();
self.call_event_handler(Event::RedrawEventsCleared);
self.runner_state = RunnerState::Idle(Instant::now());
}
RunnerState::HandlingRedraw => {
self.call_event_handler(Event::RedrawEventsCleared);
self.runner_state = RunnerState::Idle(Instant::now());
}
// If we *weren't* handling events, we don't have to do anything.
RunnerState::New | RunnerState::Idle(..) => (),
// Some control flows require a NewEvents call even if no events were received. This
// branch handles those.
RunnerState::DeferredNewEvents(wait_start) => {
match self.control_flow {
// If we had deferred a Poll, send the Poll NewEvents and EventsCleared.
ControlFlow::Poll => {
self.call_event_handler(Event::NewEvents(StartCause::Poll));
self.call_event_handler(Event::MainEventsCleared);
self.flush_redraws();
self.call_event_handler(Event::RedrawEventsCleared);
}
// If we had deferred a WaitUntil and the resume time has since been reached,
// send the resume notification and EventsCleared event.
ControlFlow::WaitUntil(resume_time) => {
if Instant::now() >= resume_time {
self.call_event_handler(Event::NewEvents(
StartCause::ResumeTimeReached {
start: wait_start,
requested_resume: resume_time,
},
));
self.call_event_handler(Event::MainEventsCleared);
self.flush_redraws();
self.call_event_handler(Event::RedrawEventsCleared);
}
}
// If we deferred a wait and no events were received, the user doesn't have to
// get an event.
ControlFlow::Wait | ControlFlow::Exit => (),
}
// Mark that we've entered an idle state.
self.runner_state = RunnerState::Idle(wait_start)
}
}
}
fn call_event_handler(&mut self, event: Event<T>) {
if self.panic_error.is_none() {
let EventLoopRunner {
ref mut panic_error,
ref mut event_handler,
ref mut control_flow,
..
} = self;
*panic_error = panic::catch_unwind(panic::AssertUnwindSafe(|| {
if *control_flow != ControlFlow::Exit {
(*event_handler)(event, control_flow);
} else {
(*event_handler)(event, &mut ControlFlow::Exit);
}
}))
.err();
}
}
}

21
src/platform_impl/windows/window.rs
View file

@ -38,7 +38,6 @@ use crate::{
drop_handler::FileDropHandler,
event_loop::{
self, EventLoopWindowTarget, DESTROY_MSG_ID, INITIAL_DPI_MSG_ID,
REQUEST_REDRAW_NO_NEWEVENTS_MSG_ID,
},
icon::{self, IconType, WinIcon},
monitor,
@ -142,20 +141,12 @@ impl Window {
#[inline]
pub fn request_redraw(&self) {
unsafe {
if self.thread_executor.trigger_newevents_on_redraw() {
winuser::RedrawWindow(
self.window.0,
ptr::null(),
ptr::null_mut(),
winuser::RDW_INTERNALPAINT,
);
} else {
let mut window_state = self.window_state.lock();
if !window_state.queued_out_of_band_redraw {
window_state.queued_out_of_band_redraw = true;
winuser::PostMessageW(self.window.0, *REQUEST_REDRAW_NO_NEWEVENTS_MSG_ID, 0, 0);
}
}
winuser::RedrawWindow(
self.window.0,
ptr::null(),
ptr::null_mut(),
winuser::RDW_INTERNALPAINT,
);
}
}