Auto merge of #24708 - szeged:webgpu-base, r=gterzian,kvark

Initial implementation of WebGPU API

<!-- Please describe your changes on the following line: -->
- Added the WebIDL bindings for GPU and GPUadapter interfaces.
- Created a background thread for WebGPU api calls.
- Established the async communication between the background thread and the WebGPU interfaces.
- Implemented the `requesAdapter` function of `navigator.gpu`

`./mach test-tidy` reports an error due to the different `arrayvec` version used in `servo` and `webgpu`, so added it to the ignore list in `servo-tidy.toml`

---
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- [x] `./mach build -d` does not report any errors
- [ ] `./mach test-tidy` does not report any errors
- [ ] These changes addresses a part of #https://github.com/servo/servo/issues/24706

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cc @jdm, cc @kvark

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1 files changed, 158 insertions, 0 deletions

diff --git a/components/script/dom/gpu.rs b/components/script/dom/gpu.rs
new file mode 100644
index 00000000000..cbde108bc01
--- /dev/null
+++ b/components/script/dom/gpu.rs
@@ -0,0 +1,158 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use crate::compartments::InCompartment;
+use crate::dom::bindings::codegen::Bindings::GPUBinding::GPURequestAdapterOptions;
+use crate::dom::bindings::codegen::Bindings::GPUBinding::{self, GPUMethods, GPUPowerPreference};
+use crate::dom::bindings::error::Error;
+use crate::dom::bindings::refcounted::{Trusted, TrustedPromise};
+use crate::dom::bindings::reflector::{reflect_dom_object, DomObject, Reflector};
+use crate::dom::bindings::root::DomRoot;
+use crate::dom::bindings::str::DOMString;
+use crate::dom::globalscope::GlobalScope;
+use crate::dom::gpuadapter::GPUAdapter;
+use crate::dom::promise::Promise;
+use crate::task_source::TaskSource;
+use dom_struct::dom_struct;
+use ipc_channel::ipc::{self, IpcSender};
+use ipc_channel::router::ROUTER;
+use js::jsapi::Heap;
+use std::rc::Rc;
+use webgpu::wgpu;
+use webgpu::{WebGPU, WebGPURequest, WebGPUResponse, WebGPUResponseResult};
+
+#[dom_struct]
+pub struct GPU {
+    reflector_: Reflector,
+}
+
+impl GPU {
+    pub fn new_inherited() -> GPU {
+        GPU {
+            reflector_: Reflector::new(),
+        }
+    }
+
+    pub fn new(global: &GlobalScope) -> DomRoot<GPU> {
+        reflect_dom_object(Box::new(GPU::new_inherited()), global, GPUBinding::Wrap)
+    }
+
+    fn wgpu_channel(&self) -> Option<WebGPU> {
+        self.global().as_window().webgpu_channel()
+    }
+}
+
+pub trait AsyncWGPUListener {
+    fn handle_response(&self, response: WebGPUResponse, promise: &Rc<Promise>);
+}
+
+struct WGPUResponse<T: AsyncWGPUListener + DomObject> {
+    trusted: TrustedPromise,
+    receiver: Trusted<T>,
+}
+
+impl<T: AsyncWGPUListener + DomObject> WGPUResponse<T> {
+    #[allow(unrooted_must_root)]
+    fn response(self, response: WebGPUResponseResult) {
+        let promise = self.trusted.root();
+        match response {
+            Ok(response) => self.receiver.root().handle_response(response, &promise),
+            Err(error) => promise.reject_error(Error::Type(format!(
+                "Received error from WebGPU thread: {}",
+                error
+            ))),
+        }
+    }
+}
+
+pub fn response_async<T: AsyncWGPUListener + DomObject + 'static>(
+    promise: &Rc<Promise>,
+    receiver: &T,
+) -> IpcSender<WebGPUResponseResult> {
+    let (action_sender, action_receiver) = ipc::channel().unwrap();
+    let (task_source, canceller) = receiver
+        .global()
+        .as_window()
+        .task_manager()
+        .dom_manipulation_task_source_with_canceller();
+    let mut trusted = Some(TrustedPromise::new(promise.clone()));
+    let trusted_receiver = Trusted::new(receiver);
+    ROUTER.add_route(
+        action_receiver.to_opaque(),
+        Box::new(move |message| {
+            let trusted = if let Some(trusted) = trusted.take() {
+                trusted
+            } else {
+                error!("WebGPU callback called twice!");
+                return;
+            };
+
+            let context = WGPUResponse {
+                trusted,
+                receiver: trusted_receiver.clone(),
+            };
+            let result = task_source.queue_with_canceller(
+                task!(process_webgpu_task: move|| {
+                    context.response(message.to().unwrap());
+                }),
+                &canceller,
+            );
+            if let Err(err) = result {
+                error!("Failed to queue GPU listener-task: {:?}", err);
+            }
+        }),
+    );
+    action_sender
+}
+
+impl GPUMethods for GPU {
+    // https://gpuweb.github.io/gpuweb/#dom-gpu-requestadapter
+    fn RequestAdapter(
+        &self,
+        options: &GPURequestAdapterOptions,
+        comp: InCompartment,
+    ) -> Rc<Promise> {
+        let promise = Promise::new_in_current_compartment(&self.global(), comp);
+        let sender = response_async(&promise, self);
+        let power_preference = match options.powerPreference {
+            Some(GPUPowerPreference::Low_power) => wgpu::PowerPreference::LowPower,
+            Some(GPUPowerPreference::High_performance) => wgpu::PowerPreference::HighPerformance,
+            None => wgpu::PowerPreference::Default,
+        };
+
+        match self.wgpu_channel() {
+            Some(channel) => {
+                channel
+                    .0
+                    .send(WebGPURequest::RequestAdapter(
+                        sender,
+                        wgpu::RequestAdapterOptions { power_preference },
+                    ))
+                    .unwrap();
+            },
+            None => promise.reject_error(Error::Type("No WebGPU thread...".to_owned())),
+        };
+        promise
+    }
+}
+
+impl AsyncWGPUListener for GPU {
+    fn handle_response(&self, response: WebGPUResponse, promise: &Rc<Promise>) {
+        match response {
+            WebGPUResponse::RequestAdapter(name, adapter) => {
+                let adapter = GPUAdapter::new(
+                    &self.global(),
+                    DOMString::from(name),
+                    Heap::default(),
+                    adapter,
+                );
+                promise.resolve_native(&adapter);
+            },
+            response => promise.reject_error(Error::Type(format!(
+                "Wrong response received for GPU from WebGPU thread {:?}",
+                response,
+            ))),
+        }
+    }
+}