1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ 2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */ 3 /* This Source Code Form is subject to the terms of the Mozilla Public 4 * License, v. 2.0. If a copy of the MPL was not distributed with this 5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ 6 7 #ifndef mozilla_GenericModule_h 8 #define mozilla_GenericModule_h 9 10 #include <type_traits> 11 12 #include "mozilla/Attributes.h" 13 #include "mozilla/Module.h" 14 15 #define NS_GENERIC_FACTORY_CONSTRUCTOR(_InstanceClass) \ 16 static nsresult _InstanceClass##Constructor(nsISupports* aOuter, \ 17 REFNSIID aIID, void** aResult) { \ 18 RefPtr<_InstanceClass> inst; \ 19 \ 20 *aResult = nullptr; \ 21 if (nullptr != aOuter) { \ 22 return NS_ERROR_NO_AGGREGATION; \ 23 } \ 24 \ 25 inst = new _InstanceClass(); \ 26 return inst->QueryInterface(aIID, aResult); \ 27 } 28 29 #define NS_GENERIC_FACTORY_CONSTRUCTOR_INIT(_InstanceClass, _InitMethod) \ 30 static nsresult _InstanceClass##Constructor(nsISupports* aOuter, \ 31 REFNSIID aIID, void** aResult) { \ 32 nsresult rv; \ 33 \ 34 RefPtr<_InstanceClass> inst; \ 35 \ 36 *aResult = nullptr; \ 37 if (nullptr != aOuter) { \ 38 return NS_ERROR_NO_AGGREGATION; \ 39 } \ 40 \ 41 inst = new _InstanceClass(); \ 42 rv = inst->_InitMethod(); \ 43 if (NS_SUCCEEDED(rv)) { \ 44 rv = inst->QueryInterface(aIID, aResult); \ 45 } \ 46 \ 47 return rv; \ 48 } 49 50 namespace mozilla { 51 namespace detail { 52 53 template <typename T> 54 struct RemoveAlreadyAddRefed { 55 using Type = T; 56 }; 57 58 template <typename T> 59 struct RemoveAlreadyAddRefed<already_AddRefed<T>> { 60 using Type = T; 61 }; 62 63 } // namespace detail 64 } // namespace mozilla 65 66 // 'Constructor' that uses an existing getter function that gets a singleton. 67 #define NS_GENERIC_FACTORY_SINGLETON_CONSTRUCTOR(_InstanceClass, _GetterProc) \ 68 static nsresult _InstanceClass##Constructor(nsISupports* aOuter, \ 69 REFNSIID aIID, void** aResult) { \ 70 RefPtr<_InstanceClass> inst; \ 71 \ 72 *aResult = nullptr; \ 73 if (nullptr != aOuter) { \ 74 return NS_ERROR_NO_AGGREGATION; \ 75 } \ 76 \ 77 using T = \ 78 mozilla::detail::RemoveAlreadyAddRefed<decltype(_GetterProc())>::Type; \ 79 static_assert( \ 80 std::is_same_v<already_AddRefed<T>, decltype(_GetterProc())>, \ 81 "Singleton constructor must return already_AddRefed"); \ 82 static_assert( \ 83 std::is_base_of<_InstanceClass, T>::value, \ 84 "Singleton constructor must return correct already_AddRefed"); \ 85 inst = _GetterProc(); \ 86 if (nullptr == inst) { \ 87 return NS_ERROR_OUT_OF_MEMORY; \ 88 } \ 89 return inst->QueryInterface(aIID, aResult); \ 90 } 91 92 #endif // mozilla_GenericModule_h 93