[api] Add v8::Isolate::IsCurrent() method

Add a helper method for isolate == v8::Isolate::TryGetCurrent();

Bug: v8:12346
Change-Id: Ibbd1ce1865b0092c8dbcfad5a3bad99fb5858980
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3251173Reviewed-by: Marja Hölttä <marja@chromium.org>
Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Auto-Submit: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77609}

include/v8-isolate.h

@@ -591,6 +591,11 @@ class V8_EXPORT Isolate {
    */
   static Isolate* TryGetCurrent();
 
+  /**
+   * Return true if this isolate is currently active.
+   **/
+  bool IsCurrent() const;
+
   /**
    * Clears the set of objects held strongly by the heap. This set of
    * objects are originally built when a WeakRef is created or

src/api/api.cc

@@ -8487,6 +8487,10 @@ Isolate* Isolate::TryGetCurrent() {
   return reinterpret_cast<Isolate*>(isolate);
 }
 
+bool Isolate::IsCurrent() const {
+  return reinterpret_cast<const i::Isolate*>(this)->IsCurrent();
+}
+
 // static
 Isolate* Isolate::Allocate() {
   return reinterpret_cast<Isolate*>(i::Isolate::New());

src/execution/isolate.h

@@ -604,6 +604,8 @@ class V8_EXPORT_PRIVATE Isolate final : private HiddenFactory {
     return isolate;
   }
 
+  bool IsCurrent() const { return this == TryGetCurrent(); }
+
   // Usually called by Init(), but can be called early e.g. to allow
   // testing components that require logging but not the whole
   // isolate.

test/cctest/test-api.cc

@@ -18570,7 +18570,17 @@ TEST(RunTwoIsolatesOnSingleThread) {
   v8::Isolate::CreateParams create_params;
   create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
   v8::Isolate* isolate1 = v8::Isolate::New(create_params);
+
+  CHECK(CcTest::isolate()->IsCurrent());
+  CHECK(!isolate1->IsCurrent());
+
   isolate1->Enter();
+  CHECK(!CcTest::isolate()->IsCurrent());
+  CHECK(isolate1->IsCurrent());
+
+  CHECK_EQ(isolate1, v8::Isolate::GetCurrent());
+  CHECK_EQ(isolate1, v8::Isolate::TryGetCurrent());
+
   v8::Persistent<v8::Context> context1;
   {
     v8::HandleScope scope(isolate1);
@@ -18591,8 +18601,16 @@ TEST(RunTwoIsolatesOnSingleThread) {
   v8::Isolate* isolate2 = v8::Isolate::New(create_params);
   v8::Persistent<v8::Context> context2;
 
+  CHECK(!CcTest::isolate()->IsCurrent());
+  CHECK(isolate1->IsCurrent());
+  CHECK(!isolate2->IsCurrent());
   {
     v8::Isolate::Scope iscope(isolate2);
+    CHECK(!isolate1->IsCurrent());
+    CHECK(isolate2->IsCurrent());
+    CHECK_EQ(isolate2, v8::Isolate::GetCurrent());
+    CHECK_EQ(isolate2, v8::Isolate::TryGetCurrent());
+
     v8::HandleScope scope(isolate2);
     context2.Reset(isolate2, Context::New(isolate2));
     v8::Local<v8::Context> context =
@@ -18604,6 +18622,10 @@ TEST(RunTwoIsolatesOnSingleThread) {
     ExpectString("function f() { return foo; }; f()", "isolate 2");
   }
 
+  CHECK(!CcTest::isolate()->IsCurrent());
+  CHECK(isolate1->IsCurrent());
+  CHECK(!isolate2->IsCurrent());
+
   {
     v8::HandleScope scope(isolate1);
     v8::Local<v8::Context> context =
@@ -18614,11 +18636,16 @@ TEST(RunTwoIsolatesOnSingleThread) {
   }
 
   isolate1->Exit();
+  CHECK(CcTest::isolate()->IsCurrent());
+  CHECK(!isolate1->IsCurrent());
+  CHECK(!isolate2->IsCurrent());
 
   // Run some stuff in default isolate.
   v8::Persistent<v8::Context> context_default;
   {
     v8::Isolate* isolate = CcTest::isolate();
+    CHECK_EQ(isolate, v8::Isolate::GetCurrent());
+    CHECK_EQ(isolate, v8::Isolate::TryGetCurrent());
     v8::Isolate::Scope iscope(isolate);
     v8::HandleScope scope(isolate);
     context_default.Reset(isolate, Context::New(isolate));