feat(ops): reland fast zero copy string arguments (#17996)

Reland https://github.com/denoland/deno/pull/16777

The codegen is disabled in async ops and when fallback to slow call is
possible (return type is a Result) to avoid hitting this V8 bug:
https://github.com/denoland/deno/issues/17159

3 files changed, 40 insertions, 22 deletions

diff --git a/ext/web/blob.rs b/ext/web/blob.rs
index 44c8f0ace..7796c18af 100644
--- a/ext/web/blob.rs
+++ b/ext/web/blob.rs
@@ -248,10 +248,10 @@ pub fn op_blob_create_object_url(
 
 #[op]
 pub fn op_blob_revoke_object_url(
-  state: &mut OpState,
-  url: String,
+  state: &mut deno_core::OpState,
+  url: &str,
 ) -> Result<(), AnyError> {
-  let url = Url::parse(&url)?;
+  let url = Url::parse(url)?;
   let blob_store = state.borrow::<BlobStore>();
   blob_store.remove_object_url(&url);
   Ok(())
diff --git a/ext/web/compression.rs b/ext/web/compression.rs
index ee129fe5a..11ea9196a 100644
--- a/ext/web/compression.rs
+++ b/ext/web/compression.rs
@@ -41,11 +41,11 @@ impl Resource for CompressionResource {
 #[op]
 pub fn op_compression_new(
   state: &mut OpState,
-  format: String,
+  format: &str,
   is_decoder: bool,
 ) -> ResourceId {
   let w = Vec::new();
-  let inner = match (format.as_str(), is_decoder) {
+  let inner = match (format, is_decoder) {
     ("deflate", true) => Inner::DeflateDecoder(ZlibDecoder::new(w)),
     ("deflate", false) => {
       Inner::DeflateEncoder(ZlibEncoder::new(w, Compression::default()))
diff --git a/ext/web/lib.rs b/ext/web/lib.rs
index c1d2c6703..2f59636fe 100644
--- a/ext/web/lib.rs
+++ b/ext/web/lib.rs
@@ -269,7 +269,7 @@ fn op_encoding_decode_single(
 #[op]
 fn op_encoding_new_decoder(
   state: &mut OpState,
-  label: String,
+  label: &str,
   fatal: bool,
   ignore_bom: bool,
 ) -> Result<ResourceId, AnyError> {
@@ -350,25 +350,43 @@ impl Resource for TextDecoderResource {
   }
 }
 
-#[op(v8)]
+#[op]
 fn op_encoding_encode_into(
-  scope: &mut v8::HandleScope,
-  input: serde_v8::Value,
+  input: Cow<'_, str>,
   buffer: &mut [u8],
   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(())
+) {
+  // 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());
+
+  // The `read` output parameter is measured in UTF-16 code units.
+  out_buf[0] = match input {
+    // Borrowed Cow strings are zero-copy views into the V8 heap.
+    // Thus, they are guarantee to be SeqOneByteString.
+    Cow::Borrowed(v) => v[..boundary].len() as u32,
+    Cow::Owned(v) => v[..boundary].encode_utf16().count() as u32,
+  };
+  out_buf[1] = boundary as u32;
 }
 
 #[op(v8)]