1 /**************************************************************************** 2 ** 3 ** Copyright (C) 2016 The Qt Company Ltd. 4 ** Copyright (C) 2013 Olivier Goffart <ogoffart@woboq.com> 5 ** Contact: https://www.qt.io/licensing/ 6 ** 7 ** This file is part of the QtCore module of the Qt Toolkit. 8 ** 9 ** $QT_BEGIN_LICENSE:LGPL$ 10 ** Commercial License Usage 11 ** Licensees holding valid commercial Qt licenses may use this file in 12 ** accordance with the commercial license agreement provided with the 13 ** Software or, alternatively, in accordance with the terms contained in 14 ** a written agreement between you and The Qt Company. For licensing terms 15 ** and conditions see https://www.qt.io/terms-conditions. For further 16 ** information use the contact form at https://www.qt.io/contact-us. 17 ** 18 ** GNU Lesser General Public License Usage 19 ** Alternatively, this file may be used under the terms of the GNU Lesser 20 ** General Public License version 3 as published by the Free Software 21 ** Foundation and appearing in the file LICENSE.LGPL3 included in the 22 ** packaging of this file. Please review the following information to 23 ** ensure the GNU Lesser General Public License version 3 requirements 24 ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. 25 ** 26 ** GNU General Public License Usage 27 ** Alternatively, this file may be used under the terms of the GNU 28 ** General Public License version 2.0 or (at your option) the GNU General 29 ** Public license version 3 or any later version approved by the KDE Free 30 ** Qt Foundation. The licenses are as published by the Free Software 31 ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 32 ** included in the packaging of this file. Please review the following 33 ** information to ensure the GNU General Public License requirements will 34 ** be met: https://www.gnu.org/licenses/gpl-2.0.html and 35 ** https://www.gnu.org/licenses/gpl-3.0.html. 36 ** 37 ** $QT_END_LICENSE$ 38 ** 39 ****************************************************************************/ 40 41 #ifndef QOBJECTDEFS_H 42 #error Do not include qobjectdefs_impl.h directly 43 #include <QtCore/qnamespace.h> 44 #endif 45 46 #if 0 47 #pragma qt_sync_skip_header_check 48 #pragma qt_sync_stop_processing 49 #endif 50 51 QT_BEGIN_NAMESPACE 52 class QObject; 53 54 namespace QtPrivate { 55 template <typename T> struct RemoveRef { typedef T Type; }; 56 template <typename T> struct RemoveRef<T&> { typedef T Type; }; 57 template <typename T> struct RemoveConstRef { typedef T Type; }; 58 template <typename T> struct RemoveConstRef<const T&> { typedef T Type; }; 59 60 /* 61 The following List classes are used to help to handle the list of arguments. 62 It follow the same principles as the lisp lists. 63 List_Left<L,N> take a list and a number as a parameter and returns (via the Value typedef, 64 the list composed of the first N element of the list 65 */ 66 // With variadic template, lists are represented using a variadic template argument instead of the lisp way 67 template <typename...> struct List {}; 68 template <typename Head, typename... Tail> struct List<Head, Tail...> { typedef Head Car; typedef List<Tail...> Cdr; }; 69 template <typename, typename> struct List_Append; 70 template <typename... L1, typename...L2> struct List_Append<List<L1...>, List<L2...>> { typedef List<L1..., L2...> Value; }; 71 template <typename L, int N> struct List_Left { 72 typedef typename List_Append<List<typename L::Car>,typename List_Left<typename L::Cdr, N - 1>::Value>::Value Value; 73 }; 74 template <typename L> struct List_Left<L, 0> { typedef List<> Value; }; 75 // List_Select<L,N> returns (via typedef Value) the Nth element of the list L 76 template <typename L, int N> struct List_Select { typedef typename List_Select<typename L::Cdr, N - 1>::Value Value; }; 77 template <typename L> struct List_Select<L,0> { typedef typename L::Car Value; }; 78 79 /* 80 trick to set the return value of a slot that works even if the signal or the slot returns void 81 to be used like function(), ApplyReturnValue<ReturnType>(&return_value) 82 if function() returns a value, the operator,(T, ApplyReturnValue<ReturnType>) is called, but if it 83 returns void, the builtin one is used without an error. 84 */ 85 template <typename T> 86 struct ApplyReturnValue { 87 void *data; 88 explicit ApplyReturnValue(void *data_) : data(data_) {} 89 }; 90 template<typename T, typename U> 91 void operator,(T &&value, const ApplyReturnValue<U> &container) { 92 if (container.data) 93 *reinterpret_cast<U *>(container.data) = std::forward<T>(value); 94 } 95 template<typename T> 96 void operator,(T, const ApplyReturnValue<void> &) {} 97 98 99 /* 100 The FunctionPointer<Func> struct is a type trait for function pointer. 101 - ArgumentCount is the number of argument, or -1 if it is unknown 102 - the Object typedef is the Object of a pointer to member function 103 - the Arguments typedef is the list of argument (in a QtPrivate::List) 104 - the Function typedef is an alias to the template parameter Func 105 - the call<Args, R>(f,o,args) method is used to call that slot 106 Args is the list of argument of the signal 107 R is the return type of the signal 108 f is the function pointer 109 o is the receiver object 110 and args is the array of pointer to arguments, as used in qt_metacall 111 112 The Functor<Func,N> struct is the helper to call a functor of N argument. 113 its call function is the same as the FunctionPointer::call function. 114 */ 115 template<class T> using InvokeGenSeq = typename T::Type; 116 117 template<int...> struct IndexesList { using Type = IndexesList; }; 118 119 template<int N, class S1, class S2> struct ConcatSeqImpl; 120 121 template<int N, int... I1, int... I2> 122 struct ConcatSeqImpl<N, IndexesList<I1...>, IndexesList<I2...>> 123 : IndexesList<I1..., (N + I2)...>{}; 124 125 template<int N, class S1, class S2> 126 using ConcatSeq = InvokeGenSeq<ConcatSeqImpl<N, S1, S2>>; 127 128 template<int N> struct GenSeq; 129 template<int N> using makeIndexSequence = InvokeGenSeq<GenSeq<N>>; 130 131 template<int N> 132 struct GenSeq : ConcatSeq<N/2, makeIndexSequence<N/2>, makeIndexSequence<N - N/2>>{}; 133 134 template<> struct GenSeq<0> : IndexesList<>{}; 135 template<> struct GenSeq<1> : IndexesList<0>{}; 136 137 template<int N> 138 struct Indexes { using Value = makeIndexSequence<N>; }; 139 140 template<typename Func> struct FunctionPointer { enum {ArgumentCount = -1, IsPointerToMemberFunction = false}; }; 141 142 template <typename, typename, typename, typename> struct FunctorCall; 143 template <int... II, typename... SignalArgs, typename R, typename Function> 144 struct FunctorCall<IndexesList<II...>, List<SignalArgs...>, R, Function> { 145 static void call(Function &f, void **arg) { 146 f((*reinterpret_cast<typename RemoveRef<SignalArgs>::Type *>(arg[II+1]))...), ApplyReturnValue<R>(arg[0]); 147 } 148 }; 149 template <int... II, typename... SignalArgs, typename R, typename... SlotArgs, typename SlotRet, class Obj> 150 struct FunctorCall<IndexesList<II...>, List<SignalArgs...>, R, SlotRet (Obj::*)(SlotArgs...)> { 151 static void call(SlotRet (Obj::*f)(SlotArgs...), Obj *o, void **arg) { 152 (o->*f)((*reinterpret_cast<typename RemoveRef<SignalArgs>::Type *>(arg[II+1]))...), ApplyReturnValue<R>(arg[0]); 153 } 154 }; 155 template <int... II, typename... SignalArgs, typename R, typename... SlotArgs, typename SlotRet, class Obj> 156 struct FunctorCall<IndexesList<II...>, List<SignalArgs...>, R, SlotRet (Obj::*)(SlotArgs...) const> { 157 static void call(SlotRet (Obj::*f)(SlotArgs...) const, Obj *o, void **arg) { 158 (o->*f)((*reinterpret_cast<typename RemoveRef<SignalArgs>::Type *>(arg[II+1]))...), ApplyReturnValue<R>(arg[0]); 159 } 160 }; 161 #if defined(__cpp_noexcept_function_type) && __cpp_noexcept_function_type >= 201510 162 template <int... II, typename... SignalArgs, typename R, typename... SlotArgs, typename SlotRet, class Obj> 163 struct FunctorCall<IndexesList<II...>, List<SignalArgs...>, R, SlotRet (Obj::*)(SlotArgs...) noexcept> { 164 static void call(SlotRet (Obj::*f)(SlotArgs...) noexcept, Obj *o, void **arg) { 165 (o->*f)((*reinterpret_cast<typename RemoveRef<SignalArgs>::Type *>(arg[II+1]))...), ApplyReturnValue<R>(arg[0]); 166 } 167 }; 168 template <int... II, typename... SignalArgs, typename R, typename... SlotArgs, typename SlotRet, class Obj> 169 struct FunctorCall<IndexesList<II...>, List<SignalArgs...>, R, SlotRet (Obj::*)(SlotArgs...) const noexcept> { 170 static void call(SlotRet (Obj::*f)(SlotArgs...) const noexcept, Obj *o, void **arg) { 171 (o->*f)((*reinterpret_cast<typename RemoveRef<SignalArgs>::Type *>(arg[II+1]))...), ApplyReturnValue<R>(arg[0]); 172 } 173 }; 174 #endif 175 176 template<class Obj, typename Ret, typename... Args> struct FunctionPointer<Ret (Obj::*) (Args...)> 177 { 178 typedef Obj Object; 179 typedef List<Args...> Arguments; 180 typedef Ret ReturnType; 181 typedef Ret (Obj::*Function) (Args...); 182 enum {ArgumentCount = sizeof...(Args), IsPointerToMemberFunction = true}; 183 template <typename SignalArgs, typename R> 184 static void call(Function f, Obj *o, void **arg) { 185 FunctorCall<typename Indexes<ArgumentCount>::Value, SignalArgs, R, Function>::call(f, o, arg); 186 } 187 }; 188 template<class Obj, typename Ret, typename... Args> struct FunctionPointer<Ret (Obj::*) (Args...) const> 189 { 190 typedef Obj Object; 191 typedef List<Args...> Arguments; 192 typedef Ret ReturnType; 193 typedef Ret (Obj::*Function) (Args...) const; 194 enum {ArgumentCount = sizeof...(Args), IsPointerToMemberFunction = true}; 195 template <typename SignalArgs, typename R> 196 static void call(Function f, Obj *o, void **arg) { 197 FunctorCall<typename Indexes<ArgumentCount>::Value, SignalArgs, R, Function>::call(f, o, arg); 198 } 199 }; 200 201 template<typename Ret, typename... Args> struct FunctionPointer<Ret (*) (Args...)> 202 { 203 typedef List<Args...> Arguments; 204 typedef Ret ReturnType; 205 typedef Ret (*Function) (Args...); 206 enum {ArgumentCount = sizeof...(Args), IsPointerToMemberFunction = false}; 207 template <typename SignalArgs, typename R> 208 static void call(Function f, void *, void **arg) { 209 FunctorCall<typename Indexes<ArgumentCount>::Value, SignalArgs, R, Function>::call(f, arg); 210 } 211 }; 212 213 #if defined(__cpp_noexcept_function_type) && __cpp_noexcept_function_type >= 201510 214 template<class Obj, typename Ret, typename... Args> struct FunctionPointer<Ret (Obj::*) (Args...) noexcept> 215 { 216 typedef Obj Object; 217 typedef List<Args...> Arguments; 218 typedef Ret ReturnType; 219 typedef Ret (Obj::*Function) (Args...) noexcept; 220 enum {ArgumentCount = sizeof...(Args), IsPointerToMemberFunction = true}; 221 template <typename SignalArgs, typename R> 222 static void call(Function f, Obj *o, void **arg) { 223 FunctorCall<typename Indexes<ArgumentCount>::Value, SignalArgs, R, Function>::call(f, o, arg); 224 } 225 }; 226 template<class Obj, typename Ret, typename... Args> struct FunctionPointer<Ret (Obj::*) (Args...) const noexcept> 227 { 228 typedef Obj Object; 229 typedef List<Args...> Arguments; 230 typedef Ret ReturnType; 231 typedef Ret (Obj::*Function) (Args...) const noexcept; 232 enum {ArgumentCount = sizeof...(Args), IsPointerToMemberFunction = true}; 233 template <typename SignalArgs, typename R> 234 static void call(Function f, Obj *o, void **arg) { 235 FunctorCall<typename Indexes<ArgumentCount>::Value, SignalArgs, R, Function>::call(f, o, arg); 236 } 237 }; 238 239 template<typename Ret, typename... Args> struct FunctionPointer<Ret (*) (Args...) noexcept> 240 { 241 typedef List<Args...> Arguments; 242 typedef Ret ReturnType; 243 typedef Ret (*Function) (Args...) noexcept; 244 enum {ArgumentCount = sizeof...(Args), IsPointerToMemberFunction = false}; 245 template <typename SignalArgs, typename R> 246 static void call(Function f, void *, void **arg) { 247 FunctorCall<typename Indexes<ArgumentCount>::Value, SignalArgs, R, Function>::call(f, arg); 248 } 249 }; 250 #endif 251 252 template<typename Function, int N> struct Functor 253 { 254 template <typename SignalArgs, typename R> 255 static void call(Function &f, void *, void **arg) { 256 FunctorCall<typename Indexes<N>::Value, SignalArgs, R, Function>::call(f, arg); 257 } 258 }; 259 260 /* 261 Logic that checks if the underlying type of an enum is signed or not. 262 Needs an external, explicit check that E is indeed an enum. Works 263 around the fact that it's undefined behavior to instantiate 264 std::underlying_type on non-enums (cf. §20.13.7.6 [meta.trans.other]). 265 */ 266 template<typename E, typename Enable = void> 267 struct IsEnumUnderlyingTypeSigned : std::false_type 268 { 269 }; 270 271 template<typename E> 272 struct IsEnumUnderlyingTypeSigned<E, typename std::enable_if<std::is_enum<E>::value>::type> 273 : std::integral_constant<bool, std::is_signed<typename std::underlying_type<E>::type>::value> 274 { 275 }; 276 277 /* 278 Logic that checks if the argument of the slot does not narrow the 279 argument of the signal when used in list initialization. Cf. §8.5.4.7 280 [dcl.init.list] for the definition of narrowing. 281 For incomplete From/To types, there's no narrowing. 282 */ 283 template<typename From, typename To, typename Enable = void> 284 struct AreArgumentsNarrowedBase : std::false_type 285 { 286 }; 287 288 template <typename T> 289 using is_bool = std::is_same<bool, typename std::decay<T>::type>; 290 291 template<typename From, typename To> 292 struct AreArgumentsNarrowedBase<From, To, typename std::enable_if<sizeof(From) && sizeof(To)>::type> 293 : std::integral_constant<bool, 294 (std::is_floating_point<From>::value && std::is_integral<To>::value) || 295 (std::is_floating_point<From>::value && std::is_floating_point<To>::value && sizeof(From) > sizeof(To)) || 296 ((std::is_pointer<From>::value || std::is_member_pointer<From>::value) && QtPrivate::is_bool<To>::value) || 297 ((std::is_integral<From>::value || std::is_enum<From>::value) && std::is_floating_point<To>::value) || 298 (std::is_integral<From>::value && std::is_integral<To>::value 299 && (sizeof(From) > sizeof(To) 300 || (std::is_signed<From>::value ? !std::is_signed<To>::value 301 : (std::is_signed<To>::value && sizeof(From) == sizeof(To))))) || 302 (std::is_enum<From>::value && std::is_integral<To>::value 303 && (sizeof(From) > sizeof(To) 304 || (IsEnumUnderlyingTypeSigned<From>::value ? !std::is_signed<To>::value 305 : (std::is_signed<To>::value && sizeof(From) == sizeof(To))))) 306 > 307 { 308 }; 309 310 /* 311 Logic that check if the arguments of the slot matches the argument of the signal. 312 To be used like this: 313 Q_STATIC_ASSERT(CheckCompatibleArguments<FunctionPointer<Signal>::Arguments, FunctionPointer<Slot>::Arguments>::value) 314 */ 315 template<typename A1, typename A2> struct AreArgumentsCompatible { 316 static int test(const typename RemoveRef<A2>::Type&); 317 static char test(...); 318 static const typename RemoveRef<A1>::Type &dummy(); 319 enum { value = sizeof(test(dummy())) == sizeof(int) }; 320 #ifdef QT_NO_NARROWING_CONVERSIONS_IN_CONNECT 321 using AreArgumentsNarrowed = AreArgumentsNarrowedBase<typename RemoveRef<A1>::Type, typename RemoveRef<A2>::Type>; 322 Q_STATIC_ASSERT_X(!AreArgumentsNarrowed::value, "Signal and slot arguments are not compatible (narrowing)"); 323 #endif 324 }; 325 template<typename A1, typename A2> struct AreArgumentsCompatible<A1, A2&> { enum { value = false }; }; 326 template<typename A> struct AreArgumentsCompatible<A&, A&> { enum { value = true }; }; 327 // void as a return value 328 template<typename A> struct AreArgumentsCompatible<void, A> { enum { value = true }; }; 329 template<typename A> struct AreArgumentsCompatible<A, void> { enum { value = true }; }; 330 template<> struct AreArgumentsCompatible<void, void> { enum { value = true }; }; 331 332 template <typename List1, typename List2> struct CheckCompatibleArguments { enum { value = false }; }; 333 template <> struct CheckCompatibleArguments<List<>, List<>> { enum { value = true }; }; 334 template <typename List1> struct CheckCompatibleArguments<List1, List<>> { enum { value = true }; }; 335 template <typename Arg1, typename Arg2, typename... Tail1, typename... Tail2> 336 struct CheckCompatibleArguments<List<Arg1, Tail1...>, List<Arg2, Tail2...>> 337 { 338 enum { value = AreArgumentsCompatible<typename RemoveConstRef<Arg1>::Type, typename RemoveConstRef<Arg2>::Type>::value 339 && CheckCompatibleArguments<List<Tail1...>, List<Tail2...>>::value }; 340 }; 341 342 /* 343 Find the maximum number of arguments a functor object can take and be still compatible with 344 the arguments from the signal. 345 Value is the number of arguments, or -1 if nothing matches. 346 */ 347 template <typename Functor, typename ArgList> struct ComputeFunctorArgumentCount; 348 349 template <typename Functor, typename ArgList, bool Done> struct ComputeFunctorArgumentCountHelper 350 { enum { Value = -1 }; }; 351 template <typename Functor, typename First, typename... ArgList> 352 struct ComputeFunctorArgumentCountHelper<Functor, List<First, ArgList...>, false> 353 : ComputeFunctorArgumentCount<Functor, 354 typename List_Left<List<First, ArgList...>, sizeof...(ArgList)>::Value> {}; 355 356 template <typename Functor, typename... ArgList> struct ComputeFunctorArgumentCount<Functor, List<ArgList...>> 357 { 358 template <typename D> static D dummy(); 359 template <typename F> static auto test(F f) -> decltype(((f.operator()((dummy<ArgList>())...)), int())); 360 static char test(...); 361 enum { 362 Ok = sizeof(test(dummy<Functor>())) == sizeof(int), 363 Value = Ok ? int(sizeof...(ArgList)) : int(ComputeFunctorArgumentCountHelper<Functor, List<ArgList...>, Ok>::Value) 364 }; 365 }; 366 367 /* get the return type of a functor, given the signal argument list */ 368 template <typename Functor, typename ArgList> struct FunctorReturnType; 369 template <typename Functor, typename ... ArgList> struct FunctorReturnType<Functor, List<ArgList...>> { 370 template <typename D> static D dummy(); 371 typedef decltype(dummy<Functor>().operator()((dummy<ArgList>())...)) Value; 372 }; 373 374 // internal base class (interface) containing functions required to call a slot managed by a pointer to function. 375 class QSlotObjectBase { 376 QAtomicInt m_ref; 377 // don't use virtual functions here; we don't want the 378 // compiler to create tons of per-polymorphic-class stuff that 379 // we'll never need. We just use one function pointer. 380 typedef void (*ImplFn)(int which, QSlotObjectBase* this_, QObject *receiver, void **args, bool *ret); 381 const ImplFn m_impl; 382 protected: 383 enum Operation { 384 Destroy, 385 Call, 386 Compare, 387 388 NumOperations 389 }; 390 public: 391 explicit QSlotObjectBase(ImplFn fn) : m_ref(1), m_impl(fn) {} 392 393 inline int ref() noexcept { return m_ref.ref(); } 394 inline void destroyIfLastRef() noexcept 395 { if (!m_ref.deref()) m_impl(Destroy, this, nullptr, nullptr, nullptr); } 396 397 inline bool compare(void **a) { bool ret = false; m_impl(Compare, this, nullptr, a, &ret); return ret; } 398 inline void call(QObject *r, void **a) { m_impl(Call, this, r, a, nullptr); } 399 protected: 400 ~QSlotObjectBase() {} 401 private: 402 Q_DISABLE_COPY_MOVE(QSlotObjectBase) 403 }; 404 405 // implementation of QSlotObjectBase for which the slot is a pointer to member function of a QObject 406 // Args and R are the List of arguments and the return type of the signal to which the slot is connected. 407 template<typename Func, typename Args, typename R> class QSlotObject : public QSlotObjectBase 408 { 409 typedef QtPrivate::FunctionPointer<Func> FuncType; 410 Func function; 411 static void impl(int which, QSlotObjectBase *this_, QObject *r, void **a, bool *ret) 412 { 413 switch (which) { 414 case Destroy: 415 delete static_cast<QSlotObject*>(this_); 416 break; 417 case Call: 418 FuncType::template call<Args, R>(static_cast<QSlotObject*>(this_)->function, static_cast<typename FuncType::Object *>(r), a); 419 break; 420 case Compare: 421 *ret = *reinterpret_cast<Func *>(a) == static_cast<QSlotObject*>(this_)->function; 422 break; 423 case NumOperations: ; 424 } 425 } 426 public: 427 explicit QSlotObject(Func f) : QSlotObjectBase(&impl), function(f) {} 428 }; 429 // implementation of QSlotObjectBase for which the slot is a functor (or lambda) 430 // N is the number of arguments 431 // Args and R are the List of arguments and the return type of the signal to which the slot is connected. 432 template<typename Func, int N, typename Args, typename R> class QFunctorSlotObject : public QSlotObjectBase 433 { 434 typedef QtPrivate::Functor<Func, N> FuncType; 435 Func function; 436 static void impl(int which, QSlotObjectBase *this_, QObject *r, void **a, bool *ret) 437 { 438 switch (which) { 439 case Destroy: 440 delete static_cast<QFunctorSlotObject*>(this_); 441 break; 442 case Call: 443 FuncType::template call<Args, R>(static_cast<QFunctorSlotObject*>(this_)->function, r, a); 444 break; 445 case Compare: // not implemented 446 case NumOperations: 447 Q_UNUSED(ret); 448 } 449 } 450 public: 451 explicit QFunctorSlotObject(Func f) : QSlotObjectBase(&impl), function(std::move(f)) {} 452 }; 453 454 // typedefs for readability for when there are no parameters 455 template <typename Func> 456 using QSlotObjectWithNoArgs = QSlotObject<Func, 457 QtPrivate::List<>, 458 typename QtPrivate::FunctionPointer<Func>::ReturnType>; 459 460 template <typename Func, typename R> 461 using QFunctorSlotObjectWithNoArgs = QFunctorSlotObject<Func, 0, QtPrivate::List<>, R>; 462 463 template <typename Func> 464 using QFunctorSlotObjectWithNoArgsImplicitReturn = QFunctorSlotObjectWithNoArgs<Func, typename QtPrivate::FunctionPointer<Func>::ReturnType>; 465 } 466 467 QT_END_NAMESPACE 468 469