Make WebUSB work on WebWorkers

Author: Yatekii

Cargo.toml

@@ -65,6 +65,8 @@ web-sys = { version = "*", features = [
     "UsbOutTransferResult",
     "UsbDirection",
     "UsbConnectionEvent",
+    "WorkerGlobalScope",
+    "WorkerNavigator",
 ] }
 wasm-bindgen-futures = { version = "*" }
 

src/platform/webusb/device.rs

@@ -1,4 +1,4 @@
-use std::{sync::Arc, time::Duration};
+use std::{io::Error, sync::Arc, time::Duration};
 
 use wasm_bindgen_futures::{js_sys::Array, wasm_bindgen::JsCast, JsFuture};
 use web_sys::{
@@ -9,7 +9,7 @@ use web_sys::{
 use crate::{
     descriptors::{validate_config_descriptor, DESCRIPTOR_TYPE_CONFIGURATION},
     transfer::{Control, EndpointType, TransferError, TransferHandle},
-    DeviceInfo, Error,
+    DeviceInfo,
 };
 
 use super::web_to_nusb_status;
@@ -22,9 +22,7 @@ pub(crate) struct WebusbDevice {
 
 impl WebusbDevice {
     pub(crate) async fn from_device_info(d: &DeviceInfo) -> Result<Arc<WebusbDevice>, Error> {
-        let window = web_sys::window().unwrap();
-        let navigator = window.navigator();
-        let usb = navigator.usb();
+        let usb = super::usb()?;
         let devices = JsFuture::from(usb.get_devices()).await.unwrap();
         let devices: Array = JsCast::unchecked_from_js(devices);
 

src/platform/webusb/enumeration.rs

@@ -9,10 +9,7 @@ use crate::{
 
 pub async fn list_devices() -> Result<impl Iterator<Item = DeviceInfo>, Error> {
     async fn inner() -> Result<Vec<DeviceInfo>, Error> {
-        let window = web_sys::window()
-            .ok_or_else(|| Error::other("WebUSB is not available on this platform"))?;
-        let navigator = window.navigator();
-        let usb = navigator.usb();
+        let usb = super::usb()?;
         let devices = JsFuture::from(usb.get_devices())
             .await
             .map_err(|e| Error::other(format!("WebUSB devices could not be listed: {e:?}")))?;

src/platform/webusb/hotplug.rs

@@ -24,9 +24,7 @@ pub(crate) struct WebusbHotplugWatch {
 
 impl WebusbHotplugWatch {
     pub fn new() -> Result<Self, Error> {
-        let window = web_sys::window().unwrap();
-        let navigator = window.navigator();
-        let usb = navigator.usb();
+        let usb = super::usb()?;
         let waker = Arc::new(AtomicWaker::new());
         let (sender, receiver) = channel();
         {

src/platform/webusb/mod.rs

@@ -3,6 +3,8 @@ mod enumeration;
 mod hotplug;
 mod transfer;
 
+use std::io::Error;
+
 pub(crate) use transfer::TransferData;
 
 pub use enumeration::{list_buses, list_devices};
@@ -11,9 +13,14 @@ pub(crate) use device::WebusbDevice as Device;
 pub(crate) use device::WebusbInterface as Interface;
 pub(crate) use hotplug::WebusbHotplugWatch as HotplugWatch;
 
+use web_sys::js_sys;
 use web_sys::js_sys::Reflect;
+use web_sys::wasm_bindgen::JsCast;
 use web_sys::wasm_bindgen::JsValue;
+use web_sys::Usb;
 use web_sys::UsbDevice;
+use web_sys::Window;
+use web_sys::WorkerGlobalScope;
 
 use crate::transfer::TransferError;
 
@@ -54,3 +61,19 @@ pub(crate) fn web_to_nusb_status(status: web_sys::UsbTransferStatus) -> Result<(
         _ => unreachable!(),
     }
 }
+
+pub(crate) fn usb() -> Result<Usb, Error> {
+    let window = js_sys::global().dyn_into::<Window>().ok();
+
+    if let Some(window) = window {
+        return Ok(window.navigator().usb());
+    }
+
+    let wgs = js_sys::global().dyn_into::<WorkerGlobalScope>().ok();
+
+    if let Some(wgs) = wgs {
+        return Ok(wgs.navigator().usb());
+    }
+
+    Err(Error::other("WebUSB is not available on this platform"))
+}