From 075853ed193e7824475605110c770d01a7f868ca Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tobias=20Nie=C3=9Fen?= <tniessen@tnie.de>
Date: Fri, 17 May 2024 00:47:12 +0200
Subject: [PATCH] buffer: make compare/equals faster

This patch adds a V8 fast API implementation for the buffer.compare
binding, which is used both by Buffer.prototype.equals and
Buffer.prototype.compare. In particular, it significantly improves the
performance of comparing buffers for equality.

PR-URL: https://github.com/nodejs/node/pull/52993
Reviewed-By: Yagiz Nizipli <yagiz.nizipli@sentry.io>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Mohammed Keyvanzadeh <mohammadkeyvanzade94@gmail.com>
---
 src/node_buffer.cc            | 22 +++++++++++++++++++++-
 src/node_external_reference.h |  5 +++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/node_buffer.cc b/src/node_buffer.cc
index e7e3ead4416a40..dda430d5bb88cb 100644
--- a/src/node_buffer.cc
+++ b/src/node_buffer.cc
@@ -57,6 +57,7 @@ using v8::ArrayBufferView;
 using v8::BackingStore;
 using v8::Context;
 using v8::EscapableHandleScope;
+using v8::FastApiTypedArray;
 using v8::FunctionCallbackInfo;
 using v8::Global;
 using v8::HandleScope;
@@ -843,6 +844,23 @@ void Compare(const FunctionCallbackInfo<Value> &args) {
   args.GetReturnValue().Set(val);
 }
 
+int32_t FastCompare(v8::Local<v8::Value>,
+                    const FastApiTypedArray<uint8_t>& a,
+                    const FastApiTypedArray<uint8_t>& b) {
+  uint8_t* data_a;
+  uint8_t* data_b;
+  CHECK(a.getStorageIfAligned(&data_a));
+  CHECK(b.getStorageIfAligned(&data_b));
+
+  size_t cmp_length = std::min(a.length(), b.length());
+
+  return normalizeCompareVal(
+      cmp_length > 0 ? memcmp(data_a, data_b, cmp_length) : 0,
+      a.length(),
+      b.length());
+}
+
+static v8::CFunction fast_compare(v8::CFunction::Make(FastCompare));
 
 // Computes the offset for starting an indexOf or lastIndexOf search.
 // Returns either a valid offset in [0...<length - 1>], ie inside the Buffer,
@@ -1409,7 +1427,7 @@ void Initialize(Local<Object> target,
                             SlowByteLengthUtf8,
                             &fast_byte_length_utf8);
   SetMethod(context, target, "copy", Copy);
-  SetMethodNoSideEffect(context, target, "compare", Compare);
+  SetFastMethodNoSideEffect(context, target, "compare", Compare, &fast_compare);
   SetMethodNoSideEffect(context, target, "compareOffset", CompareOffset);
   SetMethod(context, target, "fill", Fill);
   SetMethodNoSideEffect(context, target, "indexOfBuffer", IndexOfBuffer);
@@ -1469,6 +1487,8 @@ void RegisterExternalReferences(ExternalReferenceRegistry* registry) {
   registry->Register(FastByteLengthUtf8);
   registry->Register(Copy);
   registry->Register(Compare);
+  registry->Register(FastCompare);
+  registry->Register(fast_compare.GetTypeInfo());
   registry->Register(CompareOffset);
   registry->Register(Fill);
   registry->Register(IndexOfBuffer);
diff --git a/src/node_external_reference.h b/src/node_external_reference.h
index 599db7352d2851..be4386dcf71203 100644
--- a/src/node_external_reference.h
+++ b/src/node_external_reference.h
@@ -27,6 +27,10 @@ using CFunctionCallbackWithStrings =
     bool (*)(v8::Local<v8::Value>,
              const v8::FastOneByteString& input,
              const v8::FastOneByteString& base);
+using CFunctionCallbackWithTwoUint8Arrays =
+    int32_t (*)(v8::Local<v8::Value>,
+                const v8::FastApiTypedArray<uint8_t>&,
+                const v8::FastApiTypedArray<uint8_t>&);
 using CFunctionCallbackWithTwoUint8ArraysFallback =
     bool (*)(v8::Local<v8::Value>,
              const v8::FastApiTypedArray<uint8_t>&,
@@ -56,6 +60,7 @@ class ExternalReferenceRegistry {
   V(CFunctionCallbackWithBool)                                                 \
   V(CFunctionCallbackWithString)                                               \
   V(CFunctionCallbackWithStrings)                                              \
+  V(CFunctionCallbackWithTwoUint8Arrays)                                       \
   V(CFunctionCallbackWithTwoUint8ArraysFallback)                               \
   V(CFunctionWithUint32)                                                       \
   V(CFunctionWithDoubleReturnDouble)                                           \