perf(ext/http): Use flat list of headers for multiple set/get methods (…

…denoland#19336)

This PR attempts to resolve the first item on the list from
denoland#19330 which is about using a
flat list of interleaved key/value pairs, instead of a nested array of
tuples.

I can tackle some more if you can provide a quick example of using raw
v8 arrays, cc @mmastrac

ext/http/00_serve.js

@@ -334,7 +334,12 @@ class InnerRequest {
  if (this.#slabId === undefined) {
  throw new TypeError("request closed");
  }
- return op_http_get_request_headers(this.#slabId);
+ const headers = [];
+ const reqHeaders = op_http_get_request_headers(this.#slabId);
+ for (let i = 0; i < reqHeaders.length; i += 2) {
+ headers.push([reqHeaders[i], reqHeaders[i + 1]]);
+ }
+ return headers;
  }
 
  get slabId() {
@@ -570,7 +575,7 @@ function mapToCallback(context, callback, onError) {
  if (headers.length == 1) {
  op_http_set_response_header(req, headers[0][0], headers[0][1]);
  } else {
- op_http_set_response_headers(req, headers);
+ op_http_set_response_headers(req, headers.flat());
  }
  }
 

ext/http/http_next.rs

@@ -256,12 +256,11 @@ pub fn op_http_get_request_header(
 }
 
 #[op]
-pub fn op_http_get_request_headers(
- slab_id: SlabId,
-) -> Vec<(ByteString, ByteString)> {
+pub fn op_http_get_request_headers(slab_id: SlabId) -> Vec<ByteString> {
  let http = slab_get(slab_id);
  let headers = &http.request_parts().headers;
- let mut vec = Vec::with_capacity(headers.len());
+ // Two slots for each header key/value pair
+ let mut vec = Vec::with_capacity(headers.len() * 2);
  let mut cookies: Option<Vec<&[u8]>> = None;
  for (name, value) in headers {
  if name == COOKIE {
@@ -272,7 +271,8 @@ pub fn op_http_get_request_headers(
  }
  } else {
  let name: &[u8] = name.as_ref();
- vec.push((name.into(), value.as_bytes().into()))
+ vec.push(name.into());
+ vec.push(value.as_bytes().into());
  }
  }
 
@@ -283,11 +283,10 @@ pub fn op_http_get_request_headers(
  // TODO(mmastrac): This should probably happen on the JS side on-demand
  if let Some(cookies) = cookies {
  let cookie_sep = "; ".as_bytes();
- vec.push((
- ByteString::from(COOKIE.as_str()),
- ByteString::from(cookies.join(cookie_sep)),
- ));
+ vec.push(ByteString::from(COOKIE.as_str()));
+ vec.push(ByteString::from(cookies.join(cookie_sep)));
  }
+
  vec
 }
 
@@ -313,18 +312,15 @@ pub fn op_http_set_response_header(slab_id: SlabId, name: &str, value: &str) {
 }
 
 #[op]
-pub fn op_http_set_response_headers(
- slab_id: SlabId,
- headers: Vec<(ByteString, ByteString)>,
-) {
+pub fn op_http_set_response_headers(slab_id: SlabId, headers: Vec<ByteString>) {
  let mut http = slab_get(slab_id);
  // TODO(mmastrac): Invalid headers should be handled?
  let resp_headers = http.response().headers_mut();
  resp_headers.reserve(headers.len());
- for (name, value) in headers {
+ for header in headers.chunks_exact(2) {
  // These are valid latin-1 strings
- let name = HeaderName::from_bytes(&name).unwrap();
- let value = HeaderValue::from_bytes(&value).unwrap();
+ let name = HeaderName::from_bytes(&header[0]).unwrap();
+ let value = HeaderValue::from_bytes(&header[1]).unwrap();
  resp_headers.append(name, value);
  }
 }