perf(serde_v8): remove Mutex from ZeroCopyBuf (#15888)

1 files changed, 7 insertions, 14 deletions

diff --git a/serde_v8/magic/buffer.rs b/serde_v8/magic/buffer.rs
index eec027e17..413e56747 100644
--- a/serde_v8/magic/buffer.rs
+++ b/serde_v8/magic/buffer.rs
@@ -3,7 +3,6 @@
 use std::fmt::Debug;
 use std::ops::Deref;
 use std::ops::DerefMut;
-use std::sync::Mutex;
 
 use super::transl8::FromV8;
 use super::transl8::ToV8;
@@ -14,7 +13,7 @@ use crate::magic::transl8::impl_magic;
 // allowing us to use a single type for familiarity
 pub enum ZeroCopyBuf {
   FromV8(V8Slice),
-  ToV8(Mutex<Option<Box<[u8]>>>),
+  ToV8(Option<Box<[u8]>>),
   // Variant of the ZeroCopyBuf than is never exposed to the JS.
   // Generally used to pass Vec<u8> backed buffers to resource methods.
   Temp(Vec<u8>),
@@ -30,7 +29,7 @@ impl Debug for ZeroCopyBuf {
 
 impl ZeroCopyBuf {
   pub fn empty() -> Self {
-    ZeroCopyBuf::ToV8(Mutex::new(Some(vec![0_u8; 0].into_boxed_slice())))
+    ZeroCopyBuf::ToV8(Some(vec![0_u8; 0].into_boxed_slice()))
   }
 
   pub fn new_temp(vec: Vec<u8>) -> Self {
@@ -91,7 +90,7 @@ impl DerefMut for ZeroCopyBuf {
 
 impl From<Box<[u8]>> for ZeroCopyBuf {
   fn from(buf: Box<[u8]>) -> Self {
-    ZeroCopyBuf::ToV8(Mutex::new(Some(buf)))
+    ZeroCopyBuf::ToV8(Some(buf))
   }
 }
 
@@ -112,9 +111,7 @@ impl ToV8 for ZeroCopyBuf {
         value.into()
       }
       Self::Temp(_) => unreachable!(),
-      Self::ToV8(x) => {
-        x.get_mut().unwrap().take().expect("ZeroCopyBuf was empty")
-      }
+      Self::ToV8(ref mut x) => x.take().expect("ZeroCopyBuf was empty"),
     };
 
     if buf.is_empty() {
@@ -151,13 +148,9 @@ impl From<ZeroCopyBuf> for bytes::Bytes {
   fn from(zbuf: ZeroCopyBuf) -> bytes::Bytes {
     match zbuf {
       ZeroCopyBuf::FromV8(v) => v.into(),
-      // WARNING(AaronO): potential footgun, but will disappear in future ZeroCopyBuf refactor
-      ZeroCopyBuf::ToV8(v) => v
-        .lock()
-        .unwrap()
-        .take()
-        .expect("ZeroCopyBuf was empty")
-        .into(),
+      ZeroCopyBuf::ToV8(mut v) => {
+        v.take().expect("ZeroCopyBuf was empty").into()
+      }
       ZeroCopyBuf::Temp(v) => v.into(),
     }
   }