// Copyright 2020 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/cppgc/allocation.h> #include <include/cppgc/default-platform.h> #include <include/cppgc/garbage-collected.h> #include <include/cppgc/heap.h> #include <include/cppgc/member.h> #include <include/cppgc/platform.h> #include <include/cppgc/visitor.h> #include <include/v8.h> #include <iostream> #include <memory> #include <string> /** * This sample program shows how to set up a stand-alone cppgc heap as an * embedder of V8. Most importantly, this example shows how to reuse V8's * platform for cppgc. */ /** * Simple string rope to illustrate allocation and garbage collection below. The * rope keeps the next parts alive via regular managed reference. */ class Rope final : public cppgc::GarbageCollected<Rope> { public: explicit Rope(std::string part, Rope* next = nullptr) : part_(part), next_(next) {} void Trace(cppgc::Visitor* visitor) const { visitor->Trace(next_); } private: std::string part_; cppgc::Member<Rope> next_; friend std::ostream& operator<<(std::ostream& os, const Rope& rope); }; std::ostream& operator<<(std::ostream& os, const Rope& rope) { os << rope.part_; if (rope.next_) { os << *rope.next_; } return os; } int main(int argc, char* argv[]) { // Create a platform that is used by cppgc::Heap for execution and backend // allocation. auto cppgc_platform = std::make_shared<cppgc::DefaultPlatform>(); // Initialize the process. This must happen before any cppgc::Heap::Create() // calls. cppgc::InitializeProcess(cppgc_platform->GetPageAllocator()); // Create a managed heap. std::unique_ptr<cppgc::Heap> heap = cppgc::Heap::Create(cppgc_platform); // Allocate a string rope on the managed heap. auto* greeting = cppgc::MakeGarbageCollected<Rope>( heap->GetAllocationHandle(), "Hello ", cppgc::MakeGarbageCollected<Rope>(heap->GetAllocationHandle(), "World!")); // Manually trigger garbage collection. The object greeting is held alive // through conservative stack scanning. heap->ForceGarbageCollectionSlow("V8 embedders example", "Testing"); std::cout << *greeting << std::endl; // Gracefully shutdown the process. cppgc::ShutdownProcess(); return 0; }