perf(web): optimize encodeInto() (#15922)

2 files changed, 28 insertions, 40 deletions

diff --git a/ext/web/08_text_encoding.js b/ext/web/08_text_encoding.js
index 9e0c1f311..db724033f 100644
--- a/ext/web/08_text_encoding.js
+++ b/ext/web/08_text_encoding.js
@@ -25,6 +25,7 @@
     TypedArrayPrototypeSubarray,
     TypedArrayPrototypeSlice,
     Uint8Array,
+    Uint32Array,
   } = window.__bootstrap.primordials;
 
   class TextDecoder {
@@ -199,10 +200,16 @@
         context: "Argument 2",
         allowShared: true,
       });
-      return ops.op_encoding_encode_into(source, destination);
+      ops.op_encoding_encode_into(source, destination, encodeIntoBuf);
+      return {
+        read: encodeIntoBuf[0],
+        written: encodeIntoBuf[1],
+      };
     }
   }
 
+  const encodeIntoBuf = new Uint32Array(2);
+
   webidl.configurePrototype(TextEncoder);
   const TextEncoderPrototype = TextEncoder.prototype;
 
diff --git a/ext/web/lib.rs b/ext/web/lib.rs
index 9c1e85952..0eec63ab9 100644
--- a/ext/web/lib.rs
+++ b/ext/web/lib.rs
@@ -10,7 +10,9 @@ use deno_core::error::type_error;
 use deno_core::error::AnyError;
 use deno_core::include_js_files;
 use deno_core::op;
+use deno_core::serde_v8;
 use deno_core::url::Url;
+use deno_core::v8;
 use deno_core::ByteString;
 use deno_core::CancelHandle;
 use deno_core::Extension;
@@ -19,11 +21,11 @@ use deno_core::Resource;
 use deno_core::ResourceId;
 use deno_core::U16String;
 use deno_core::ZeroCopyBuf;
+
 use encoding_rs::CoderResult;
 use encoding_rs::Decoder;
 use encoding_rs::DecoderResult;
 use encoding_rs::Encoding;
-use serde::Serialize;
 use std::borrow::Cow;
 use std::cell::RefCell;
 use std::fmt;
@@ -314,46 +316,25 @@ impl Resource for TextDecoderResource {
   }
 }
 
-#[derive(Serialize)]
-#[serde(rename_all = "camelCase")]
-struct EncodeIntoResult {
-  read: usize,
-  written: usize,
-}
-
-#[op]
+#[op(v8)]
 fn op_encoding_encode_into(
-  input: String,
+  scope: &mut v8::HandleScope,
+  input: serde_v8::Value,
   buffer: &mut [u8],
-) -> EncodeIntoResult {
-  // Since `input` is already UTF-8, we can simply find the last UTF-8 code
-  // point boundary from input that fits in `buffer`, and copy the bytes up to
-  // that point.
-  let boundary = if buffer.len() >= input.len() {
-    input.len()
-  } else {
-    let mut boundary = buffer.len();
-
-    // The maximum length of a UTF-8 code point is 4 bytes.
-    for _ in 0..4 {
-      if input.is_char_boundary(boundary) {
-        break;
-      }
-      debug_assert!(boundary > 0);
-      boundary -= 1;
-    }
-
-    debug_assert!(input.is_char_boundary(boundary));
-    boundary
-  };
-
-  buffer[..boundary].copy_from_slice(input[..boundary].as_bytes());
-
-  EncodeIntoResult {
-    // The `read` output parameter is measured in UTF-16 code units.
-    read: input[..boundary].encode_utf16().count(),
-    written: boundary,
-  }
+  out_buf: &mut [u32],
+) -> Result<(), AnyError> {
+  let s = v8::Local::<v8::String>::try_from(input.v8_value)?;
+
+  let mut nchars = 0;
+  out_buf[1] = s.write_utf8(
+    scope,
+    buffer,
+    Some(&mut nchars),
+    v8::WriteOptions::NO_NULL_TERMINATION
+      | v8::WriteOptions::REPLACE_INVALID_UTF8,
+  ) as u32;
+  out_buf[0] = nchars as u32;
+  Ok(())
 }
 
 /// Creates a [`CancelHandle`] resource that can be used to cancel invocations of certain ops.