third_party/WebKit/Source/platform/heap/Visitor.cpp

// Copyright 2016 The Chromium 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 "platform/heap/Visitor.h"

#include "platform/heap/BlinkGC.h"
#include "platform/heap/MarkingVisitor.h"
#include "platform/heap/ThreadState.h"
#include "wtf/PtrUtil.h"
#include <memory>

namespace blink {

std::unique_ptr<Visitor> Visitor::create(ThreadState* state,
                                         BlinkGC::GCType gcType) {
  switch (gcType) {
    case BlinkGC::GCWithSweep:
    case BlinkGC::GCWithoutSweep:
      return wrapUnique(new MarkingVisitor<Visitor::GlobalMarking>(state));
    case BlinkGC::TakeSnapshot:
      return wrapUnique(new MarkingVisitor<Visitor::SnapshotMarking>(state));
    case BlinkGC::ThreadTerminationGC:
      return wrapUnique(new MarkingVisitor<Visitor::ThreadLocalMarking>(state));
    case BlinkGC::ThreadLocalWeakProcessing:
      return wrapUnique(new MarkingVisitor<Visitor::WeakProcessing>(state));
    default:
      ASSERT_NOT_REACHED();
  }
  return nullptr;
}

Visitor::Visitor(ThreadState* state, MarkingMode markingMode)
    : VisitorHelper(state), m_markingMode(markingMode) {
  // See ThreadState::runScheduledGC() why we need to already be in a
  // GCForbiddenScope before any safe point is entered.
  state->enterGCForbiddenScope();

  ASSERT(state->checkThread());
}

Visitor::~Visitor() {
  state()->leaveGCForbiddenScope();
}

}  // namespace blink