v8/samples/cppgc/hello-world.cc
Leszek Swirski 0ff8205261 [test] Add a unittest platform setup mixin
Change the unittest runner to no longer uncondtionally set up a default
platform in the "environment", but to instead make platform set-up part
of the "mixin" framework for test fixtures.

Requires modifying some tests that expect the platform to be available,
and all flag implications resolved, before the mixin constructors run.

We still keep the environment for setting up the process for cppgc. This
process setup can only be done once per process, so it can no longer use
the platform -- that's ok though, the page allocator used by cppgc's
process initialisation doesn't have to be the same as the platform's so
we can just pass in a separate new one.

Change-Id: Ic8ccf39722e8212962c5bba87350c4b304388a7c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3571886
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79820}
2022-04-06 13:07:43 +00:00

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2.6 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 <iostream>
#include <memory>
#include <string>
#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/visitor.h"
#if !CPPGC_IS_STANDALONE
#include "include/v8-initialization.h"
#endif // !CPPGC_IS_STANDALONE
/**
* 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_(std::move(part)), next_(next) {}
void Trace(cppgc::Visitor* visitor) const { visitor->Trace(next_); }
private:
const std::string part_;
const 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>();
#if !CPPGC_IS_STANDALONE
// When initializing a stand-alone cppgc heap in a regular V8 build, the
// internal V8 platform will be reused. Reusing the V8 platform requires
// initializing it properly.
v8::V8::InitializePlatform(cppgc_platform->GetV8Platform());
#endif // !CPPGC_IS_STANDALONE
// 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.
Rope* 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;
}