Cache global Crypto object

Author: daxpedda

.github/workflows/tests.yml

@@ -234,44 +234,56 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@stable
-      - name: Install precompiled wasm-pack
-        shell: bash
-        run: |
-          VERSION=v0.13.1
-          URL=https://github.com/rustwasm/wasm-pack/releases/download/${VERSION}/wasm-pack-${VERSION}-x86_64-unknown-linux-musl.tar.gz
-          wget -O - $URL | tar -xz --strip-components=1 -C ~/.cargo/bin
-          wasm-pack --version
+        with:
+          targets: wasm32-unknown-unknown
+      # - name: Install precompiled wasm-bindgen
+      #   shell: bash
+      #   run: |
+      #     VERSION=v0.2.97
+      #     URL=https://github.com/rustwasm/wasm-bindgen/releases/download/${VERSION}/wasm-bindgen-${VERSION}-x86_64-unknown-linux-musl.tar.gz
+      #     wget -O - $URL | tar -xz --strip-components=1 -C ~/.cargo/bin
+      #     wasm-bindgen --version
+      - uses: taiki-e/cache-cargo-install-action@v2
+        with:
+          tool: wasm-bindgen-cli
+          git: https://github.com/daxpedda/wasm-bindgen
+          rev: 82fe725521ab1b95226408027530b3357919d6be
       - uses: Swatinem/rust-cache@v2
       - name: Test (Node)
         env:
           RUSTFLAGS: -Dwarnings --cfg getrandom_backend="wasm_js"
-        run: wasm-pack test --node -- --features std
+        run: cargo test --target wasm32-unknown-unknown --features std
       - name: Test (Firefox)
         env:
+          GECKODRIVER: geckodriver
           WASM_BINDGEN_USE_BROWSER: 1
           RUSTFLAGS: -Dwarnings --cfg getrandom_backend="wasm_js"
-        run: wasm-pack test --headless --firefox -- --features std
+        run: cargo test --target wasm32-unknown-unknown --features std
       - name: Test (Chrome)
         env:
+          CHROMEDRIVER: chromedriver
           WASM_BINDGEN_USE_BROWSER: 1
           RUSTFLAGS: -Dwarnings --cfg getrandom_backend="wasm_js"
-        run: wasm-pack test --headless --chrome -- --features std
+        run: cargo test --target wasm32-unknown-unknown --features std
       - name: Test (dedicated worker)
         env:
+          GECKODRIVER: geckodriver
           WASM_BINDGEN_USE_DEDICATED_WORKER: 1
           RUSTFLAGS: -Dwarnings --cfg getrandom_backend="wasm_js"
-        run: wasm-pack test --headless --firefox -- --features std
+        run: cargo test --target wasm32-unknown-unknown --features std
       - name: Test (shared worker)
         env:
+          GECKODRIVER: geckodriver
           WASM_BINDGEN_USE_SHARED_WORKER: 1
           RUSTFLAGS: -Dwarnings --cfg getrandom_backend="wasm_js"
-        run: wasm-pack test --headless --firefox -- --features std
+        run: cargo test --target wasm32-unknown-unknown --features std
       - name: Test (service worker)
         env:
+          # Firefox doesn't support module service workers and therefor can't import scripts
+          CHROMEDRIVER: chromedriver
           WASM_BINDGEN_USE_SERVICE_WORKER: 1
           RUSTFLAGS: -Dwarnings --cfg getrandom_backend="wasm_js"
-        # Firefox doesn't support module service workers and therefor can't import scripts
-        run: wasm-pack test --headless --chrome -- --features std
+        run: cargo test --target wasm32-unknown-unknown --features std
 
   wasi:
     name: WASI

Cargo.toml

@@ -99,3 +99,8 @@ pre-build = [
   "rm base.tar.xz",
   "rm -rf /tmp/netbsd",
 ]
+
+[patch.crates-io]
+wasm-bindgen = { git = "https://github.com/daxpedda/wasm-bindgen", branch = "getrandom" }
+js-sys = { git = "https://github.com/daxpedda/wasm-bindgen", branch = "getrandom" }
+wasm-bindgen-test = { git = "https://github.com/daxpedda/wasm-bindgen", branch = "getrandom" }

src/backends/wasm_js.rs

@@ -1,4 +1,5 @@
 //! Implementation for WASM based on Web and Node.js
+
 use crate::Error;
 use core::mem::MaybeUninit;
 
@@ -7,52 +8,47 @@ pub use crate::util::{inner_u32, inner_u64};
 #[cfg(not(all(target_arch = "wasm32", any(target_os = "unknown", target_os = "none"))))]
 compile_error!("`wasm_js` backend can be enabled only for OS-less WASM targets!");
 
-use js_sys::{global, Uint8Array};
-use wasm_bindgen::{prelude::wasm_bindgen, JsCast, JsValue};
+use js_sys::Uint8Array;
+use wasm_bindgen::{prelude::wasm_bindgen, JsValue};
 
 // Size of our temporary Uint8Array buffer used with WebCrypto methods
 // Maximum is 65536 bytes see https://developer.mozilla.org/en-US/docs/Web/API/Crypto/getRandomValues
 const CRYPTO_BUFFER_SIZE: u16 = 256;
 
 pub fn fill_inner(dest: &mut [MaybeUninit<u8>]) -> Result<(), Error> {
-    let global: Global = global().unchecked_into();
-    let crypto = global.crypto();
-
-    if !crypto.is_object() {
-        return Err(Error::WEB_CRYPTO);
-    }
-
-    // getRandomValues does not work with all types of WASM memory,
-    // so we initially write to browser memory to avoid exceptions.
-    let buf = Uint8Array::new_with_length(CRYPTO_BUFFER_SIZE.into());
-    for chunk in dest.chunks_mut(CRYPTO_BUFFER_SIZE.into()) {
-        let chunk_len: u32 = chunk
-            .len()
-            .try_into()
-            .expect("chunk length is bounded by CRYPTO_BUFFER_SIZE");
-        // The chunk can be smaller than buf's length, so we call to
-        // JS to create a smaller view of buf without allocation.
-        let sub_buf = buf.subarray(0, chunk_len);
-
-        if crypto.get_random_values(&sub_buf).is_err() {
-            return Err(Error::WEB_GET_RANDOM_VALUES);
+    CRYPTO.with(|crypto| {
+        let crypto = crypto.as_ref().ok_or(Error::WEB_CRYPTO)?;
+
+        // getRandomValues does not work with all types of WASM memory,
+        // so we initially write to browser memory to avoid exceptions.
+        let buf = Uint8Array::new_with_length(CRYPTO_BUFFER_SIZE.into());
+        for chunk in dest.chunks_mut(CRYPTO_BUFFER_SIZE.into()) {
+            let chunk_len: u32 = chunk
+                .len()
+                .try_into()
+                .expect("chunk length is bounded by CRYPTO_BUFFER_SIZE");
+            // The chunk can be smaller than buf's length, so we call to
+            // JS to create a smaller view of buf without allocation.
+            let sub_buf = buf.subarray(0, chunk_len);
+
+            if crypto.get_random_values(&sub_buf).is_err() {
+                return Err(Error::WEB_GET_RANDOM_VALUES);
+            }
+
+            // SAFETY: `sub_buf`'s length is the same length as `chunk`
+            unsafe { sub_buf.raw_copy_to_ptr(chunk.as_mut_ptr().cast::<u8>()) };
         }
-
-        // SAFETY: `sub_buf`'s length is the same length as `chunk`
-        unsafe { sub_buf.raw_copy_to_ptr(chunk.as_mut_ptr().cast::<u8>()) };
-    }
-    Ok(())
+        Ok(())
+    })
 }
 
 #[wasm_bindgen]
 extern "C" {
-    // Return type of js_sys::global()
-    type Global;
     // Web Crypto API: Crypto interface (https://www.w3.org/TR/WebCryptoAPI/)
     type Crypto;
-    // Getters for the Crypto API
-    #[wasm_bindgen(method, getter)]
-    fn crypto(this: &Global) -> Crypto;
+    // Holds the global `Crypto` object.
+    #[wasm_bindgen(thread_local_v2, js_name = crypto)]
+    static CRYPTO: Option<Crypto>;
     // Crypto.getRandomValues()
     #[wasm_bindgen(method, js_name = getRandomValues, catch)]
     fn get_random_values(this: &Crypto, buf: &Uint8Array) -> Result<(), JsValue>;