OxiPNG + threads PoC

codecs/oxipng/src/lib.rs

@@ -1,8 +1,44 @@
 mod malloc_shim;
 
+use js_sys::Array;
 use wasm_bindgen::prelude::*;
+use wasm_bindgen::{JsCast, JsValue};
 use oxipng::AlphaOptim;
 
+#[wasm_bindgen]
+extern "C" {
+    type Worker;
+
+    #[wasm_bindgen(method, js_name = postMessage)]
+    fn post_message(worker: &Worker, msg: JsValue);
+}
+
+#[wasm_bindgen]
+pub fn start_main_thread(workers: Array) {
+    // console_log::init_with_level(log::Level::Trace);
+
+    rayon::ThreadPoolBuilder::new()
+        .num_threads(workers.length() as _)
+        .spawn_handler(move |thread| {
+            Ok(workers.pop().unchecked_into::<Worker>().post_message({
+                let arr = Array::new();
+                arr.push(&wasm_bindgen::module());
+                arr.push(&wasm_bindgen::memory());
+                arr.push(&JsValue::from(Box::into_raw(Box::new(thread)) as u32));
+                arr.into()
+            }))
+        })
+        .build_global()
+        .unwrap_throw()
+}
+
+#[wasm_bindgen]
+pub fn start_worker_thread(thread: *mut rayon::ThreadBuilder) {
+  // console_log::init_with_level(log::Level::Trace);
+
+  unsafe { Box::from_raw(thread) }.run()
+}
+
 #[wasm_bindgen(catch)]
 pub fn optimise(data: &[u8], level: u8) -> Vec<u8> {
   let mut options = oxipng::Options::from_preset(level);