/* -*- 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/. */

#ifndef mozilla_GenericModule_h
#define mozilla_GenericModule_h

#include "mozilla/Attributes.h"
#include "mozilla/Module.h"

#define NS_GENERIC_FACTORY_CONSTRUCTOR(_InstanceClass)                        \
static nsresult                                                               \
_InstanceClass##Constructor(nsISupports *aOuter, REFNSIID aIID,               \
                            void **aResult)                                   \
{                                                                             \
  RefPtr<_InstanceClass> inst;                                                \
                                                                              \
  *aResult = nullptr;                                                         \
  if (nullptr != aOuter) {                                                    \
    return NS_ERROR_NO_AGGREGATION;                                           \
  }                                                                           \
                                                                              \
  inst = new _InstanceClass();                                                \
  return inst->QueryInterface(aIID, aResult);                                 \
}

#define NS_GENERIC_FACTORY_CONSTRUCTOR_INIT(_InstanceClass, _InitMethod)      \
static nsresult                                                               \
_InstanceClass##Constructor(nsISupports *aOuter, REFNSIID aIID,               \
                            void **aResult)                                   \
{                                                                             \
  nsresult rv;                                                                \
                                                                              \
  RefPtr<_InstanceClass> inst;                                                \
                                                                              \
  *aResult = nullptr;                                                         \
  if (nullptr != aOuter) {                                                    \
    return NS_ERROR_NO_AGGREGATION;                                           \
  }                                                                           \
                                                                              \
  inst = new _InstanceClass();                                                \
  rv = inst->_InitMethod();                                                   \
  if (NS_SUCCEEDED(rv)) {                                                     \
    rv = inst->QueryInterface(aIID, aResult);                                 \
  }                                                                           \
                                                                              \
  return rv;                                                                  \
}

namespace mozilla {
namespace detail {

template<typename T>
struct RemoveAlreadyAddRefed
{
  using Type = T;
};

template<typename T>
struct RemoveAlreadyAddRefed<already_AddRefed<T>>
{
  using Type = T;
};

} // namespace detail
} // namespace mozilla

// 'Constructor' that uses an existing getter function that gets a singleton.
#define NS_GENERIC_FACTORY_SINGLETON_CONSTRUCTOR(_InstanceClass, _GetterProc) \
static nsresult                                                               \
_InstanceClass##Constructor(nsISupports *aOuter, REFNSIID aIID,               \
                            void **aResult)                                   \
{                                                                             \
  RefPtr<_InstanceClass> inst;                                                \
                                                                              \
  *aResult = nullptr;                                                         \
  if (nullptr != aOuter) {                                                    \
    return NS_ERROR_NO_AGGREGATION;                                           \
  }                                                                           \
                                                                              \
  using T = mozilla::detail::RemoveAlreadyAddRefed<decltype(_GetterProc())>::Type; \
  static_assert(mozilla::IsSame<already_AddRefed<T>, decltype(_GetterProc())>::value, \
                "Singleton constructor must return already_AddRefed");        \
  static_assert(mozilla::IsBaseOf<_InstanceClass, T>::value,                  \
                "Singleton constructor must return correct already_AddRefed");\
  inst = _GetterProc();                                                       \
  if (nullptr == inst) {                                                      \
    return NS_ERROR_OUT_OF_MEMORY;                                            \
  }                                                                           \
  return inst->QueryInterface(aIID, aResult);                                 \
}

#endif // mozilla_GenericModule_h