/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "SystemGroup.h"

#include "mozilla/AbstractThread.h"
#include "mozilla/Move.h"
#include "mozilla/StaticPtr.h"
#include "mozilla/UniquePtr.h"
#include "nsINamed.h"

using namespace mozilla;

class SystemGroupImpl final : public SchedulerGroup {
 public:
  SystemGroupImpl();
  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(SystemGroupImpl, override)

  static void InitStatic();
  static void ShutdownStatic();
  static SystemGroupImpl* Get();

  static bool Initialized() { return !!sSingleton; }

 private:
  ~SystemGroupImpl() = default;
  static StaticRefPtr<SystemGroupImpl> sSingleton;
};

StaticRefPtr<SystemGroupImpl> SystemGroupImpl::sSingleton;

SystemGroupImpl::SystemGroupImpl() {
  CreateEventTargets(/* aNeedValidation = */ true);
}

/* static */
void SystemGroupImpl::InitStatic() {
  MOZ_ASSERT(!sSingleton);
  MOZ_ASSERT(NS_IsMainThread());
  sSingleton = new SystemGroupImpl();
}

/* static */
void SystemGroupImpl::ShutdownStatic() {
  sSingleton->Shutdown(true);
  sSingleton = nullptr;
}

/* static */
SystemGroupImpl* SystemGroupImpl::Get() {
  MOZ_ASSERT(sSingleton);
  return sSingleton.get();
}

void SystemGroup::InitStatic() { SystemGroupImpl::InitStatic(); }

void SystemGroup::Shutdown() { SystemGroupImpl::ShutdownStatic(); }

bool SystemGroup::Initialized() { return SystemGroupImpl::Initialized(); }

/* static */
nsresult SystemGroup::Dispatch(TaskCategory aCategory,
                               already_AddRefed<nsIRunnable>&& aRunnable) {
  if (!SystemGroupImpl::Initialized()) {
    return NS_DispatchToMainThread(std::move(aRunnable));
  }
  return SystemGroupImpl::Get()->Dispatch(aCategory, std::move(aRunnable));
}

/* static */
nsISerialEventTarget* SystemGroup::EventTargetFor(TaskCategory aCategory) {
  if (!SystemGroupImpl::Initialized()) {
    return GetMainThreadSerialEventTarget();
  }
  return SystemGroupImpl::Get()->EventTargetFor(aCategory);
}

/* static */
AbstractThread* SystemGroup::AbstractMainThreadFor(TaskCategory aCategory) {
  MOZ_ASSERT(SystemGroupImpl::Initialized());
  return SystemGroupImpl::Get()->AbstractMainThreadFor(aCategory);
}