http2: refactor read mechanism

Refactor the read mechanism to completely avoid copying.

Instead of copying individual `DATA` frame contents into buffers,
create `ArrayBuffer` instances for all socket reads and emit
slices of those `ArrayBuffer`s to JS.

Backport-PR-URL: https://github.com/nodejs/node/pull/20456
PR-URL: https://github.com/nodejs/node/pull/18030
Reviewed-By: James M Snell <jasnell@gmail.com>

1 files changed, 12 insertions, 18 deletions

diff --git a/lib/internal/http2/core.js b/lib/internal/http2/core.js
index 3e68ed4a59..bc1067e996 100644
--- a/lib/internal/http2/core.js
+++ b/lib/internal/http2/core.js
@@ -277,7 +277,7 @@ function submitRstStream(code) {
 // point, close them. If there is an open fd for file send, close that also.
 // At this point the underlying node::http2:Http2Stream handle is no
 // longer usable so destroy it also.
-function onStreamClose(code, hasData) {
+function onStreamClose(code) {
   const stream = this[kOwner];
   if (stream.destroyed)
     return;
@@ -285,8 +285,7 @@ function onStreamClose(code, hasData) {
   const state = stream[kState];
 
   debug(`Http2Stream ${stream[kID]} [Http2Session ` +
-        `${sessionName(stream[kSession][kType])}]: closed with code ${code}` +
-        ` [has data? ${hasData}]`);
+        `${sessionName(stream[kSession][kType])}]: closed with code ${code}`);
 
   if (!stream.closed) {
     // Unenroll from timeouts
@@ -304,13 +303,14 @@ function onStreamClose(code, hasData) {
 
   if (state.fd !== undefined)
     tryClose(state.fd);
-  stream[kMaybeDestroy](null, code, hasData);
+  stream.push(null);
+  stream[kMaybeDestroy](null, code);
 }
 
 // Receives a chunk of data for a given stream and forwards it on
 // to the Http2Stream Duplex for processing.
-function onStreamRead(nread, buf, handle) {
-  const stream = handle[kOwner];
+function onStreamRead(nread, buf) {
+  const stream = this[kOwner];
   if (nread >= 0 && !stream.destroyed) {
     debug(`Http2Stream ${stream[kID]} [Http2Session ` +
           `${sessionName(stream[kSession][kType])}]: receiving data chunk ` +
@@ -318,7 +318,7 @@ function onStreamRead(nread, buf, handle) {
     stream[kUpdateTimer]();
     if (!stream.push(buf)) {
       if (!stream.destroyed)  // we have to check a second time
-        handle.readStop();
+        this.readStop();
     }
     return;
   }
@@ -1427,13 +1427,8 @@ function streamOnResume() {
 }
 
 function streamOnPause() {
-  // if (!this.destroyed && !this.pending)
-  //   this[kHandle].readStop();
-}
-
-function handleFlushData(self) {
   if (!this.destroyed && !this.pending)
-    this[kHandle].flushData();
+    this[kHandle].readStop();
 }
 
 // If the writable side of the Http2Stream is still open, emit the
@@ -1679,11 +1674,10 @@ class Http2Stream extends Duplex {
       this.push(null);
       return;
     }
-    const flushfn = handleFlushData.bind(this);
     if (!this.pending) {
-      flushfn();
+      streamOnResume.call(this);
     } else {
-      this.once('ready', flushfn);
+      this.once('ready', streamOnResume);
     }
   }
 
@@ -1822,10 +1816,10 @@ class Http2Stream extends Duplex {
 
   // The Http2Stream can be destroyed if it has closed and if the readable
   // side has received the final chunk.
-  [kMaybeDestroy](error, code = NGHTTP2_NO_ERROR, hasData = true) {
+  [kMaybeDestroy](error, code = NGHTTP2_NO_ERROR) {
     if (error == null) {
       if (code === NGHTTP2_NO_ERROR &&
-          ((!this._readableState.ended && hasData) ||
+          (!this._readableState.ended ||
           !this._writableState.ended ||
           this._writableState.pendingcb > 0 ||
           !this.closed)) {