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Make canvas in WindowBuilder safe (#3320)

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daxpedda 2023-12-26 01:22:10 +01:00 • committed by GitHub
parent 843d7904d6
commit e0fea25b06
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GPG key ID: 4AEE18F83AFDEB23
10 changed files with 214 additions and 169 deletions
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165
src/platform_impl/web/cursor.rs
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@ -9,12 +9,8 @@ use std::{
task::{Poll, Waker},
};
use crate::{
cursor::{BadImage, Cursor, CursorImage},
platform_impl::platform::r#async,
};
use crate::cursor::{BadImage, Cursor, CursorImage};
use cursor_icon::CursorIcon;
use once_cell::sync::Lazy;
use wasm_bindgen::{closure::Closure, JsCast};
use wasm_bindgen_futures::JsFuture;
use web_sys::{
@ -22,9 +18,9 @@ use web_sys::{
ImageBitmapRenderingContext, ImageData, PremultiplyAlpha, Url, Window,
};
use self::thread_safe::ThreadSafe;
use super::{backend::Style, r#async::AsyncSender, EventLoopWindowTarget};
use super::backend::Style;
use super::main_thread::{MainThreadMarker, MainThreadSafe};
use super::EventLoopWindowTarget;
#[derive(Debug)]
pub(crate) enum CustomCursorBuilder {
@ -51,7 +47,7 @@ impl CustomCursorBuilder {
}
#[derive(Clone, Debug)]
pub struct CustomCursor(Arc<Inner>);
pub struct CustomCursor(Arc<MainThreadSafe<RefCell<ImageState>>>);
impl Hash for CustomCursor {
fn hash<H: Hasher>(&self, state: &mut H) {
@ -68,14 +64,22 @@ impl PartialEq for CustomCursor {
impl Eq for CustomCursor {}
impl CustomCursor {
fn new(main_thread: MainThreadMarker) -> Self {
Self(Arc::new(MainThreadSafe::new(
main_thread,
RefCell::new(ImageState::Loading(None)),
)))
}
pub(crate) fn build<T>(
builder: CustomCursorBuilder,
window_target: &EventLoopWindowTarget<T>,
) -> Self {
Lazy::force(&DROP_HANDLER);
let main_thread = window_target.runner.main_thread();
Self(match builder {
match builder {
CustomCursorBuilder::Image(image) => ImageState::from_rgba(
main_thread,
window_target.runner.window(),
window_target.runner.document().clone(),
&image,
@ -84,47 +88,7 @@ impl CustomCursor {
url,
hotspot_x,
hotspot_y,
} => ImageState::from_url(url, hotspot_x, hotspot_y),
})
}
}
#[derive(Debug)]
struct Inner(Option<ThreadSafe<RefCell<ImageState>>>);
static DROP_HANDLER: Lazy<AsyncSender<ThreadSafe<RefCell<ImageState>>>> = Lazy::new(|| {
let (sender, receiver) = r#async::channel();
wasm_bindgen_futures::spawn_local(async move { while receiver.next().await.is_ok() {} });
sender
});
impl Inner {
fn new() -> Arc<Self> {
Arc::new(Inner(Some(ThreadSafe::new(RefCell::new(
ImageState::Loading(None),
)))))
}
fn get(&self) -> &RefCell<ImageState> {
self.0
.as_ref()
.expect("value has accidently already been dropped")
.get()
}
}
impl Drop for Inner {
fn drop(&mut self) {
let value = self
.0
.take()
.expect("value has accidently already been dropped");
if !value.in_origin_thread() {
DROP_HANDLER
.send(value)
.expect("sender dropped in main thread")
} => ImageState::from_url(main_thread, url, hotspot_x, hotspot_y),
}
}
}
@ -133,8 +97,9 @@ impl Drop for Inner {
pub struct CursorState(Rc<RefCell<State>>);
impl CursorState {
pub fn new(style: Style) -> Self {
pub fn new(main_thread: MainThreadMarker, style: Style) -> Self {
Self(Rc::new(RefCell::new(State {
main_thread,
style,
visible: true,
cursor: SelectedCursor::default(),
@ -147,7 +112,9 @@ impl CursorState {
match cursor {
Cursor::Icon(icon) => {
if let SelectedCursor::ImageLoading { state, .. } = &this.cursor {
if let ImageState::Loading(state) = state.get().borrow_mut().deref_mut() {
if let ImageState::Loading(state) =
state.0.get(this.main_thread).borrow_mut().deref_mut()
{
state.take();
}
}
@ -155,10 +122,16 @@ impl CursorState {
this.cursor = SelectedCursor::Named(icon);
this.set_style();
}
Cursor::Custom(cursor) => match cursor.inner.0.get().borrow_mut().deref_mut() {
Cursor::Custom(cursor) => match cursor
.inner
.0
.get(this.main_thread)
.borrow_mut()
.deref_mut()
{
ImageState::Loading(state) => {
this.cursor = SelectedCursor::ImageLoading {
state: cursor.inner.0.clone(),
state: cursor.inner.clone(),
previous: mem::take(&mut this.cursor).into(),
};
*state = Some(Rc::downgrade(&self.0));
@ -187,6 +160,7 @@ impl CursorState {
#[derive(Debug)]
struct State {
main_thread: MainThreadMarker,
style: Style,
visible: bool,
cursor: SelectedCursor,
@ -210,7 +184,7 @@ impl State {
enum SelectedCursor {
Named(CursorIcon),
ImageLoading {
state: Arc<Inner>,
state: CustomCursor,
previous: Previous,
},
ImageReady(Rc<Image>),
@ -264,7 +238,12 @@ enum ImageState {
}
impl ImageState {
fn from_rgba(window: &Window, document: Document, image: &CursorImage) -> Arc<Inner> {
fn from_rgba(
main_thread: MainThreadMarker,
window: &Window,
document: Document,
image: &CursorImage,
) -> CustomCursor {
// 1. Create an `ImageData` from the RGBA data.
// 2. Create an `ImageBitmap` from the `ImageData`.
// 3. Draw `ImageBitmap` on an `HTMLCanvasElement`.
@ -316,10 +295,11 @@ impl ImageState {
.expect("unexpected exception in `createImageBitmap()`"),
);
let this = Inner::new();
#[allow(clippy::arc_with_non_send_sync)]
let this = CustomCursor::new(main_thread);
wasm_bindgen_futures::spawn_local({
let weak = Arc::downgrade(&this);
let weak = Arc::downgrade(&this.0);
let CursorImage {
width,
height,
@ -394,7 +374,7 @@ impl ImageState {
let Some(this) = weak.upgrade() else {
return;
};
let mut this = this.get().borrow_mut();
let mut this = this.get(main_thread).borrow_mut();
let Some(blob) = blob else {
log::error!("creating custom cursor failed");
@ -422,17 +402,24 @@ impl ImageState {
.expect("unexpected exception in `URL.createObjectURL()`")
};
Self::decode(weak, url, true, hotspot_x, hotspot_y).await;
Self::decode(main_thread, weak, url, true, hotspot_x, hotspot_y).await;
}
});
this
}
fn from_url(url: String, hotspot_x: u16, hotspot_y: u16) -> Arc<Inner> {
let this = Inner::new();
fn from_url(
main_thread: MainThreadMarker,
url: String,
hotspot_x: u16,
hotspot_y: u16,
) -> CustomCursor {
#[allow(clippy::arc_with_non_send_sync)]
let this = CustomCursor::new(main_thread);
wasm_bindgen_futures::spawn_local(Self::decode(
Arc::downgrade(&this),
main_thread,
Arc::downgrade(&this.0),
url,
false,
hotspot_x,
@ -443,7 +430,8 @@ impl ImageState {
}
async fn decode(
weak: sync::Weak<Inner>,
main_thread: MainThreadMarker,
weak: sync::Weak<MainThreadSafe<RefCell<ImageState>>>,
url: String,
object: bool,
hotspot_x: u16,
@ -462,7 +450,7 @@ impl ImageState {
let Some(this) = weak.upgrade() else {
return;
};
let mut this = this.get().borrow_mut();
let mut this = this.get(main_thread).borrow_mut();
let ImageState::Loading(state) = this.deref_mut() else {
unreachable!("found invalid state");
@ -533,46 +521,3 @@ impl Image {
})
}
}
mod thread_safe {
use std::mem;
use std::thread::{self, ThreadId};
#[derive(Debug)]
pub struct ThreadSafe<T> {
origin_thread: ThreadId,
value: T,
}
impl<T> ThreadSafe<T> {
pub fn new(value: T) -> Self {
Self {
origin_thread: thread::current().id(),
value,
}
}
pub fn get(&self) -> &T {
if self.origin_thread == thread::current().id() {
&self.value
} else {
panic!("value not accessible outside its origin thread")
}
}
pub fn in_origin_thread(&self) -> bool {
self.origin_thread == thread::current().id()
}
}
impl<T> Drop for ThreadSafe<T> {
fn drop(&mut self) {
if mem::needs_drop::<T>() && self.origin_thread != thread::current().id() {
panic!("value can't be dropped outside its origin thread")
}
}
}
unsafe impl<T> Send for ThreadSafe<T> {}
unsafe impl<T> Sync for ThreadSafe<T> {}
}