From a622c5df27e908bff152ce7374c47dabfdba0bba Mon Sep 17 00:00:00 2001
From: Divy Srivastava <dj.srivastava23@gmail.com>
Date: Sun, 9 Oct 2022 03:08:38 -0700
Subject: perf(ext/crypto): optimize `getRandomValues` (#16212)

---
 ext/crypto/00_crypto.js |  5 +++++
 ext/crypto/lib.rs       | 12 ++++++------
 2 files changed, 11 insertions(+), 6 deletions(-)

(limited to 'ext/crypto')

diff --git a/ext/crypto/00_crypto.js b/ext/crypto/00_crypto.js
index 907308325..7b21c9287 100644
--- a/ext/crypto/00_crypto.js
+++ b/ext/crypto/00_crypto.js
@@ -4652,6 +4652,11 @@
       webidl.assertBranded(this, CryptoPrototype);
       const prefix = "Failed to execute 'getRandomValues' on 'Crypto'";
       webidl.requiredArguments(arguments.length, 1, { prefix });
+      // Fast path for Uint8Array
+      if (ObjectPrototypeIsPrototypeOf(Uint8ArrayPrototype, arrayBufferView)) {
+        ops.op_crypto_get_random_values(arrayBufferView);
+        return arrayBufferView;
+      }
       arrayBufferView = webidl.converters.ArrayBufferView(arrayBufferView, {
         prefix,
         context: "Argument 1",
diff --git a/ext/crypto/lib.rs b/ext/crypto/lib.rs
index d949135e7..f09982920 100644
--- a/ext/crypto/lib.rs
+++ b/ext/crypto/lib.rs
@@ -132,24 +132,24 @@ pub fn op_crypto_base64url_encode(data: ZeroCopyBuf) -> String {
   data
 }
 
-#[op]
+#[op(fast)]
 pub fn op_crypto_get_random_values(
   state: &mut OpState,
-  mut zero_copy: ZeroCopyBuf,
+  out: &mut [u8],
 ) -> Result<(), AnyError> {
-  if zero_copy.len() > 65536 {
+  if out.len() > 65536 {
     return Err(
-      deno_web::DomExceptionQuotaExceededError::new(&format!("The ArrayBufferView's byte length ({}) exceeds the number of bytes of entropy available via this API (65536)", zero_copy.len()))
+      deno_web::DomExceptionQuotaExceededError::new(&format!("The ArrayBufferView's byte length ({}) exceeds the number of bytes of entropy available via this API (65536)", out.len()))
         .into(),
     );
   }
 
   let maybe_seeded_rng = state.try_borrow_mut::<StdRng>();
   if let Some(seeded_rng) = maybe_seeded_rng {
-    seeded_rng.fill(&mut *zero_copy);
+    seeded_rng.fill(out);
   } else {
     let mut rng = thread_rng();
-    rng.fill(&mut *zero_copy);
+    rng.fill(out);
   }
 
   Ok(())
-- 
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