From 4f96b841221b91015ce6bc4df69f0c0a6d8cea84 Mon Sep 17 00:00:00 2001
From: murgatroid99 <mlumish@google.com>
Date: Fri, 31 Mar 2017 11:22:52 -0700
Subject: [PATCH] Large message latency improvements: remove a memcpy and a
 Buffer construtor call

---
 ext/byte_buffer.cc | 39 ++++++++++++++-------------------------
 ext/byte_buffer.h  |  4 ----
 ext/slice.cc       |  5 ++---
 3 files changed, 16 insertions(+), 32 deletions(-)

diff --git a/ext/byte_buffer.cc b/ext/byte_buffer.cc
index 7d6fb198..a99b96be 100644
--- a/ext/byte_buffer.cc
+++ b/ext/byte_buffer.cc
@@ -45,6 +45,7 @@
 namespace grpc {
 namespace node {
 
+using Nan::Callback;
 using Nan::MaybeLocal;
 
 using v8::Function;
@@ -62,7 +63,11 @@ grpc_byte_buffer *BufferToByteBuffer(Local<Value> buffer) {
 }
 
 namespace {
-void delete_buffer(char *data, void *hint) { delete[] data; }
+void delete_buffer(char *data, void *hint) {
+  grpc_slice *slice = static_cast<grpc_slice *>(hint);
+  grpc_slice_unref(*slice);
+  delete slice;
+}
 }
 
 Local<Value> ByteBufferToBuffer(grpc_byte_buffer *buffer) {
@@ -75,31 +80,15 @@ Local<Value> ByteBufferToBuffer(grpc_byte_buffer *buffer) {
     Nan::ThrowError("Error initializing byte buffer reader.");
     return scope.Escape(Nan::Undefined());
   }
-  grpc_slice slice = grpc_byte_buffer_reader_readall(&reader);
-  size_t length = GRPC_SLICE_LENGTH(slice);
-  char *result = new char[length];
-  memcpy(result, GRPC_SLICE_START_PTR(slice), length);
-  grpc_slice_unref(slice);
-  return scope.Escape(MakeFastBuffer(
-      Nan::NewBuffer(result, length, delete_buffer, NULL).ToLocalChecked()));
+  grpc_slice *slice = new grpc_slice;
+  *slice = grpc_byte_buffer_reader_readall(&reader);
+  grpc_byte_buffer_reader_destroy(&reader);
+  char *result = reinterpret_cast<char *>(GRPC_SLICE_START_PTR(*slice));
+  size_t length = GRPC_SLICE_LENGTH(*slice);
+  Local<Value> buf =
+      Nan::NewBuffer(result, length, delete_buffer, slice).ToLocalChecked();
+  return scope.Escape(buf);
 }
 
-Local<Value> MakeFastBuffer(Local<Value> slowBuffer) {
-  Nan::EscapableHandleScope scope;
-  Local<Object> globalObj = Nan::GetCurrentContext()->Global();
-  MaybeLocal<Value> constructorValue = Nan::Get(
-      globalObj, Nan::New("Buffer").ToLocalChecked());
-  Local<Function> bufferConstructor = Local<Function>::Cast(
-      constructorValue.ToLocalChecked());
-  const int argc = 3;
-  Local<Value> consArgs[argc] = {
-    slowBuffer,
-    Nan::New<Number>(::node::Buffer::Length(slowBuffer)),
-    Nan::New<Number>(0)
-  };
-  MaybeLocal<Object> fastBuffer = Nan::NewInstance(bufferConstructor,
-                                                   argc, consArgs);
-  return scope.Escape(fastBuffer.ToLocalChecked());
-}
 }  // namespace node
 }  // namespace grpc
diff --git a/ext/byte_buffer.h b/ext/byte_buffer.h
index 55bc0ab3..e8c4ac90 100644
--- a/ext/byte_buffer.h
+++ b/ext/byte_buffer.h
@@ -50,10 +50,6 @@ grpc_byte_buffer *BufferToByteBuffer(v8::Local<v8::Value> buffer);
 /* Convert a grpc_byte_buffer to a Node.js Buffer */
 v8::Local<v8::Value> ByteBufferToBuffer(grpc_byte_buffer *buffer);
 
-/* Convert a ::node::Buffer to a fast Buffer, as defined in the Node
-   Buffer documentation */
-v8::Local<v8::Value> MakeFastBuffer(v8::Local<v8::Value> slowBuffer);
-
 }  // namespace node
 }  // namespace grpc
 
diff --git a/ext/slice.cc b/ext/slice.cc
index 98a80b3d..104dd9e2 100644
--- a/ext/slice.cc
+++ b/ext/slice.cc
@@ -37,7 +37,6 @@
 #include <grpc/support/alloc.h>
 
 #include "slice.h"
-#include "byte_buffer.h"
 
 namespace grpc {
 namespace node {
@@ -93,9 +92,9 @@ Local<Value> CreateBufferFromSlice(const grpc_slice slice) {
   Nan::EscapableHandleScope scope;
   grpc_slice *slice_ptr = new grpc_slice;
   *slice_ptr = grpc_slice_ref(slice);
-  return scope.Escape(MakeFastBuffer(Nan::NewBuffer(
+  return scope.Escape(Nan::NewBuffer(
       const_cast<char *>(reinterpret_cast<const char *>(GRPC_SLICE_START_PTR(*slice_ptr))),
-      GRPC_SLICE_LENGTH(*slice_ptr), SliceFreeCallback, slice_ptr).ToLocalChecked()));
+      GRPC_SLICE_LENGTH(*slice_ptr), SliceFreeCallback, slice_ptr).ToLocalChecked());
 }
 
 }  // namespace node