src: add incr/decr operators for Reference

This commit adds operator overloads for increment/decrement to
AliasedBuffer::Reference.
The motivation for doing this is to hopefully make code that needs
to increment/decrement a little simpler.

PR-URL: https://github.com/nodejs/node/pull/19083
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/test/cctest/test_aliased_buffer.cc b/test/cctest/test_aliased_buffer.cc
index 0eaddf7735..7afa466133 100644
--- a/test/cctest/test_aliased_buffer.cc
+++ b/test/cctest/test_aliased_buffer.cc
@@ -207,3 +207,33 @@ TEST_F(AliasBufferTest, SharedArrayBuffer4) {
       int8_t, v8::Int8Array,
       int32_t, v8::Int32Array>(isolate_, 1, 3, 1);
 }
+
+TEST_F(AliasBufferTest, OperatorOverloads) {
+  v8::Isolate::Scope isolate_scope(isolate_);
+  v8::HandleScope handle_scope(isolate_);
+  v8::Local<v8::Context> context = v8::Context::New(isolate_);
+  v8::Context::Scope context_scope(context);
+  const size_t size = 10;
+  AliasedBuffer<uint32_t, v8::Uint32Array> ab{isolate_, size};
+
+  EXPECT_EQ(static_cast<uint32_t>(1), ab[0] = 1);
+  EXPECT_EQ(static_cast<uint32_t>(4), ab[0] += 3);
+  EXPECT_EQ(static_cast<uint32_t>(2), ab[0] -= 2);
+  EXPECT_EQ(static_cast<uint32_t>(-2), -ab[0]);
+}
+
+TEST_F(AliasBufferTest, OperatorOverloadsRefs) {
+  v8::Isolate::Scope isolate_scope(isolate_);
+  v8::HandleScope handle_scope(isolate_);
+  v8::Local<v8::Context> context = v8::Context::New(isolate_);
+  v8::Context::Scope context_scope(context);
+  AliasedBuffer<uint32_t, v8::Uint32Array> ab{isolate_, 2};
+  using Reference = AliasedBuffer<uint32_t, v8::Uint32Array>::Reference;
+  Reference ref = ab[0];
+  Reference ref_value = ab[1] = 2;
+
+  EXPECT_EQ(static_cast<uint32_t>(2), ref = ref_value);
+  EXPECT_EQ(static_cast<uint32_t>(4), ref += ref_value);
+  EXPECT_EQ(static_cast<uint32_t>(2), ref -= ref_value);
+  EXPECT_EQ(static_cast<uint32_t>(-2), -ref);
+}