From 569287b15b6482a39f2c816f103574c3b35351f8 Mon Sep 17 00:00:00 2001
From: Marcos Casagrande <marcoscvp90@gmail.com>
Date: Tue, 4 Oct 2022 15:48:50 +0200
Subject: perf(ext/fetch): consume body using ops (#16038)

This commit adds a fast path to `Request` and `Response` that
make consuming request bodies much faster when using `Body#text`,
`Body#arrayBuffer`, and `Body#blob`, if the body is a FastStream.
Because the response bodies for `fetch` are FastStream, this speeds up
consuming `fetch` response bodies significantly.
---
 core/ops_builtin.rs | 21 +++++++++++++++++++++
 core/resources.rs   |  4 ++++
 2 files changed, 25 insertions(+)

(limited to 'core')

diff --git a/core/ops_builtin.rs b/core/ops_builtin.rs
index 6ca2a132c..7393d4b69 100644
--- a/core/ops_builtin.rs
+++ b/core/ops_builtin.rs
@@ -34,6 +34,7 @@ pub(crate) fn init_builtins() -> Extension {
       op_add::decl(),
       // // TODO(@AaronO): track IO metrics for builtin streams
       op_read::decl(),
+      op_read_all::decl(),
       op_write::decl(),
       op_shutdown::decl(),
       op_metrics::decl(),
@@ -168,6 +169,26 @@ async fn op_read(
   resource.read_return(buf).await.map(|(n, _)| n as u32)
 }
 
+#[op]
+async fn op_read_all(
+  state: Rc<RefCell<OpState>>,
+  rid: ResourceId,
+) -> Result<ZeroCopyBuf, Error> {
+  let resource = state.borrow().resource_table.get_any(rid)?;
+  let (min, maximum) = resource.size_hint();
+  let size = maximum.unwrap_or(min) as usize;
+
+  let mut buffer = Vec::with_capacity(size);
+  loop {
+    let tmp = ZeroCopyBuf::new_temp(vec![0u8; 64 * 1024]);
+    let (nread, tmp) = resource.clone().read_return(tmp).await?;
+    if nread == 0 {
+      return Ok(buffer.into());
+    }
+    buffer.extend_from_slice(&tmp[..nread]);
+  }
+}
+
 #[op]
 async fn op_write(
   state: Rc<RefCell<OpState>>,
diff --git a/core/resources.rs b/core/resources.rs
index 56c9298af..1a1ba3193 100644
--- a/core/resources.rs
+++ b/core/resources.rs
@@ -64,6 +64,10 @@ pub trait Resource: Any + 'static {
   fn backing_fd(self: Rc<Self>) -> Option<std::os::unix::prelude::RawFd> {
     None
   }
+
+  fn size_hint(&self) -> (u64, Option<u64>) {
+    (0, None)
+  }
 }
 
 impl dyn Resource {
-- 
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