[wasm] Managed<T> ensures T's lifetime does not leak past Isolate's

test/unittests/managed-unittests.cc

+// Copyright 2017 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "include/v8.h"
+#include "src/flags.h"
+#include "src/managed.h"
+#include "src/objects-inl.h"
+
+#include "test/unittests/test-utils.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using namespace v8::base;
+using namespace v8::internal;
+
+using ManagedTest = TestWithIsolate;
+
+class DeleteRecorder {
+ public:
+  explicit DeleteRecorder(bool* deleted) : deleted_(deleted) {
+    *deleted_ = false;
+  }
+  ~DeleteRecorder() { *deleted_ = true; }
+  static void Deleter(void* value) {
+    delete reinterpret_cast<DeleteRecorder*>(value);
+  }
+
+ private:
+  bool* deleted_;
+};
+
+class ScopedExposeGc {
+ public:
+  ScopedExposeGc() : was_exposed_(i::FLAG_expose_gc) {
+    i::FLAG_expose_gc = true;
+  }
+  ~ScopedExposeGc() { i::FLAG_expose_gc = was_exposed_; }
+
+ private:
+  const bool was_exposed_;
+};
+
+TEST_F(ManagedTest, ManagedCollect) {
+  bool deleted1 = false;
+  bool deleted2 = false;
+  DeleteRecorder* d1 = new DeleteRecorder(&deleted1);
+  DeleteRecorder* d2 = new DeleteRecorder(&deleted2);
+  Isolate::ManagedLifeline* list_node =
+      isolate()->RegisterForReleaseAtTeardown(d2, DeleteRecorder::Deleter);
+  {
+    HandleScope scope(isolate());
+    auto handle = Managed<DeleteRecorder>::New(isolate(), d1);
+    USE(handle);
+  }
+
+  v8::Isolate* v8_isolate = reinterpret_cast<v8::Isolate*>(isolate());
+  {
+    ScopedExposeGc expose_gc;
+    v8_isolate->RequestGarbageCollectionForTesting(
+        v8::Isolate::kFullGarbageCollection);
+  }
+  CHECK(deleted1);
+  CHECK(!deleted2);
+  isolate()->UnregisterFromReleaseAtTeardown(list_node);
+  CHECK_NULL(list_node);
+  delete d2;
+}
+
+TEST_F(ManagedTest, DisposeCollect) {
+  v8::Isolate::CreateParams create_params;
+  create_params.array_buffer_allocator = isolate()->array_buffer_allocator();
+
+  v8::Isolate* new_isolate = v8::Isolate::New(create_params);
+  new_isolate->Enter();
+  Isolate* i_new_isolate = reinterpret_cast<i::Isolate*>(new_isolate);
+  bool deleted1 = false;
+  bool deleted2 = false;
+  DeleteRecorder* d1 = new DeleteRecorder(&deleted1);
+  DeleteRecorder* d2 = new DeleteRecorder(&deleted2);
+  {
+    HandleScope scope(i_new_isolate);
+    auto handle = Managed<DeleteRecorder>::New(i_new_isolate, d1);
+    USE(handle);
+  }
+  i_new_isolate->RegisterForReleaseAtTeardown(d2, DeleteRecorder::Deleter);
+
+  new_isolate->Exit();
+  new_isolate->Dispose();
+  CHECK(deleted1);
+  CHECK(deleted2);
+}