v8/samples/cppgc/hello-world.cc
Michael Lippautz 22cd803263 cppgc: Update README
Give a little bit of introduction to Oilpan and provide a few links to
navigate the project.

Bug: chromium:1056170
Change-Id: I4ef8c256c8de7932e3393017be6c58ba48ca45f2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3114141
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76457}
2021-08-24 11:56:53 +00:00

65 lines
2.0 KiB
C++

// 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 <cppgc/allocation.h>
#include <cppgc/default-platform.h>
#include <cppgc/garbage-collected.h>
#include <cppgc/heap.h>
#include <cppgc/member.h>
#include <cppgc/visitor.h>
#include <iostream>
#include <memory>
#include <string>
/**
* This sample program shows how to set up a stand-alone cppgc heap.
*/
/**
* 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) {
os << rope.part_;
if (rope.next_) {
os << *rope.next_;
}
return os;
}
};
int main(int argc, char* argv[]) {
// Create a default 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::DefaultPlatform::InitializeProcess(cppgc_platform.get());
// 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("CppGC example", "Testing");
std::cout << *greeting << std::endl;
// Gracefully shutdown the process.
cppgc::ShutdownProcess();
return 0;
}