gmock-actions.h source code [include/gmock/gmock-actions.h]

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29
30	// Google Mock - a framework for writing C++ mock classes.
31	//
32	// The ACTION family of macros can be used in a namespace scope to*
33	// define custom actions easily. The syntax:
34	//
35	// ACTION(name) { statements; }
36	//
37	// will define an action with the given name that executes the
38	// statements. The value returned by the statements will be used as
39	// the return value of the action. Inside the statements, you can
40	// refer to the K-th (0-based) argument of the mock function by
41	// 'argK', and refer to its type by 'argK_type'. For example:
42	//
43	// ACTION(IncrementArg1) {
44	// arg1_type temp = arg1;
45	// return ++(temp);*
46	// }
47	//
48	// allows you to write
49	//
50	// ...WillOnce(IncrementArg1());
51	//
52	// You can also refer to the entire argument tuple and its type by
53	// 'args' and 'args_type', and refer to the mock function type and its
54	// return type by 'function_type' and 'return_type'.
55	//
56	// Note that you don't need to specify the types of the mock function
57	// arguments. However rest assured that your code is still type-safe:
58	// you'll get a compiler error if arg1 doesn't support the ++*
59	// operator, or if the type of ++(arg1) isn't compatible with the*
60	// mock function's return type, for example.
61	//
62	// Sometimes you'll want to parameterize the action. For that you can use
63	// another macro:
64	//
65	// ACTION_P(name, param_name) { statements; }
66	//
67	// For example:
68	//
69	// ACTION_P(Add, n) { return arg0 + n; }
70	//
71	// will allow you to write:
72	//
73	// ...WillOnce(Add(5));
74	//
75	// Note that you don't need to provide the type of the parameter
76	// either. If you need to reference the type of a parameter named
77	// 'foo', you can write 'foo_type'. For example, in the body of
78	// ACTION_P(Add, n) above, you can write 'n_type' to refer to the type
79	// of 'n'.
80	//
81	// We also provide ACTION_P2, ACTION_P3, ..., up to ACTION_P10 to support
82	// multi-parameter actions.
83	//
84	// For the purpose of typing, you can view
85	//
86	// ACTION_Pk(Foo, p1, ..., pk) { ... }
87	//
88	// as shorthand for
89	//
90	// template <typename p1_type, ..., typename pk_type>
91	// FooActionPk<p1_type, ..., pk_type> Foo(p1_type p1, ..., pk_type pk) { ... }
92	//
93	// In particular, you can provide the template type arguments
94	// explicitly when invoking Foo(), as in Foo<long, bool>(5, false);
95	// although usually you can rely on the compiler to infer the types
96	// for you automatically. You can assign the result of expression
97	// Foo(p1, ..., pk) to a variable of type FooActionPk<p1_type, ...,
98	// pk_type>. This can be useful when composing actions.
99	//
100	// You can also overload actions with different numbers of parameters:
101	//
102	// ACTION_P(Plus, a) { ... }
103	// ACTION_P2(Plus, a, b) { ... }
104	//
105	// While it's tempting to always use the ACTION macros when defining*
106	// a new action, you should also consider implementing ActionInterface
107	// or using MakePolymorphicAction() instead, especially if you need to
108	// use the action a lot. While these approaches require more work,
109	// they give you more control on the types of the mock function
110	// arguments and the action parameters, which in general leads to
111	// better compiler error messages that pay off in the long run. They
112	// also allow overloading actions based on parameter types (as opposed
113	// to just based on the number of parameters).
114	//
115	// CAVEAT:
116	//
117	// ACTION() can only be used in a namespace scope as templates cannot be*
118	// declared inside of a local class.
119	// Users can, however, define any local functors (e.g. a lambda) that
120	// can be used as actions.
121	//
122	// MORE INFORMATION:
123	//
124	// To learn more about using these macros, please search for 'ACTION' on
125	// https://github.com/google/googletest/blob/main/docs/gmock_cook_book.md
126
127	// IWYU pragma: private, include "gmock/gmock.h"
128	// IWYU pragma: friend gmock/.*
129
130	#ifndef GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_ACTIONS_H_
131	#define GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_ACTIONS_H_
132
133	#ifndef _WIN32_WCE
134	#include <errno.h>
135	#endif
136
137	#include <algorithm>
138	#include <exception>
139	#include <functional>
140	#include <memory>
141	#include <string>
142	#include <tuple>
143	#include <type_traits>
144	#include <utility>
145
146	#include "gmock/internal/gmock-internal-utils.h"
147	#include "gmock/internal/gmock-port.h"
148	#include "gmock/internal/gmock-pp.h"
149
150	GTEST_DISABLE_MSC_WARNINGS_PUSH_(`4100`)
151
152	namespace testing {
153
154	// To implement an action Foo, define:
155	// 1. a class FooAction that implements the ActionInterface interface, and
156	// 2. a factory function that creates an Action object from a
157	// const FooAction.*
158	//
159	// The two-level delegation design follows that of Matcher, providing
160	// consistency for extension developers. It also eases ownership
161	// management as Action objects can now be copied like plain values.
162
163	namespace internal {
164
165	// BuiltInDefaultValueGetter<T, true>::Get() returns a
166	// default-constructed T value. BuiltInDefaultValueGetter<T,
167	// false>::Get() crashes with an error.
168	//
169	// This primary template is used when kDefaultConstructible is true.
170	template <typename T, bool kDefaultConstructible>
171	struct BuiltInDefaultValueGetter {
172	static T Get() { return T(); }
173	};
174	template <typename T>
175	struct BuiltInDefaultValueGetter<T, false> {
176	static T Get() {
177	Assert(condition: false, __FILE__, __LINE__,
178	msg: "Default action undefined for the function return type.");
179	#if defined(__GNUC__) \|\| defined(__clang__)
180	__builtin_unreachable();
181	#elif defined(_MSC_VER)
182	__assume(`0`);
183	#else
184	return Invalid<T>();
185	// The above statement will never be reached, but is required in
186	// order for this function to compile.
187	#endif
188	}
189	};
190
191	// BuiltInDefaultValue<T>::Get() returns the "built-in" default value
192	// for type T, which is NULL when T is a raw pointer type, 0 when T is
193	// a numeric type, false when T is bool, or "" when T is string or
194	// std::string. In addition, in C++11 and above, it turns a
195	// default-constructed T value if T is default constructible. For any
196	// other type T, the built-in default T value is undefined, and the
197	// function will abort the process.
198	template <typename T>
199	class BuiltInDefaultValue {
200	public:
201	// This function returns true if and only if type T has a built-in default
202	// value.
203	static bool Exists() { return ::std::is_default_constructible<T>::value; }
204
205	static T Get() {
206	return BuiltInDefaultValueGetter<
207	T, ::std::is_default_constructible<T>::value>::Get();
208	}
209	};
210
211	// This partial specialization says that we use the same built-in
212	// default value for T and const T.
213	template <typename T>
214	class BuiltInDefaultValue<const T> {
215	public:
216	static bool Exists() { return BuiltInDefaultValue<T>::Exists(); }
217	static T Get() { return BuiltInDefaultValue<T>::Get(); }
218	};
219
220	// This partial specialization defines the default values for pointer
221	// types.
222	template <typename T>
223	class BuiltInDefaultValue<T*> {
224	public:
225	static bool Exists() { return true; }
226	static T* Get() { return nullptr; }
227	};
228
229	// The following specializations define the default values for
230	// specific types we care about.
231	#define GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(type, value) \
232	template <> \
233	class BuiltInDefaultValue<type> { \
234	public: \
235	static bool Exists() { return true; } \
236	static type Get() { return value; } \
237	}
238
239	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(void, ); // NOLINT
240	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(::std::string, "");
241	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(bool, false);
242	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned char, `'\0'`);
243	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed char, `'\0'`);
244	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(char, `'\0'`);
245
246	// There's no need for a default action for signed wchar_t, as that
247	// type is the same as wchar_t for gcc, and invalid for MSVC.
248	//
249	// There's also no need for a default action for unsigned wchar_t, as
250	// that type is the same as unsigned int for gcc, and invalid for
251	// MSVC.
252	#if GMOCK_WCHAR_T_IS_NATIVE_
253	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(wchar_t, `0U`); // NOLINT
254	#endif
255
256	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned short, `0U`); // NOLINT
257	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed short, `0`); // NOLINT
258	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned int, `0U`);
259	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed int, `0`);
260	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned long, `0UL`); // NOLINT
261	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed long, `0L`); // NOLINT
262	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned long long, `0`); // NOLINT
263	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed long long, `0`); // NOLINT
264	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(float, `0`);
265	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(double, `0`);
266
267	#undef GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_
268
269	// Partial implementations of metaprogramming types from the standard library
270	// not available in C++11.
271
272	template <typename P>
273	struct negation
274	// NOLINTNEXTLINE
275	: std::integral_constant<bool, bool(!P::value)> {};
276
277	// Base case: with zero predicates the answer is always true.
278	template <typename...>
279	struct conjunction : std::true_type {};
280
281	// With a single predicate, the answer is that predicate.
282	template <typename P1>
283	struct conjunction<P1> : P1 {};
284
285	// With multiple predicates the answer is the first predicate if that is false,
286	// and we recurse otherwise.
287	template <typename P1, typename... Ps>
288	struct conjunction<P1, Ps...>
289	: std::conditional<bool(P1::value), conjunction<Ps...>, P1>::type {};
290
291	template <typename...>
292	struct disjunction : std::false_type {};
293
294	template <typename P1>
295	struct disjunction<P1> : P1 {};
296
297	template <typename P1, typename... Ps>
298	struct disjunction<P1, Ps...>
299	// NOLINTNEXTLINE
300	: std::conditional<!bool(P1::value), disjunction<Ps...>, P1>::type {};
301
302	template <typename...>
303	using void_t = void;
304
305	// Detects whether an expression of type `From` can be implicitly converted to
306	// `To` according to [conv]. In C++17, [conv]/3 defines this as follows:
307	//
308	// An expression e can be implicitly converted to a type T if and only if
309	// the declaration T t=e; is well-formed, for some invented temporary
310	// variable t ([dcl.init]).
311	//
312	// [conv]/2 implies we can use function argument passing to detect whether this
313	// initialization is valid.
314	//
315	// Note that this is distinct from is_convertible, which requires this be valid:
316	//
317	// To test() {
318	// return declval<From>();
319	// }
320	//
321	// In particular, is_convertible doesn't give the correct answer when `To` and
322	// `From` are the same non-moveable type since `declval<From>` will be an rvalue
323	// reference, defeating the guaranteed copy elision that would otherwise make
324	// this function work.
325	//
326	// REQUIRES: `From` is not cv void.
327	template <typename From, typename To>
328	struct is_implicitly_convertible {
329	private:
330	// A function that accepts a parameter of type T. This can be called with type
331	// U successfully only if U is implicitly convertible to T.
332	template <typename T>
333	static void Accept(T);
334
335	// A function that creates a value of type T.
336	template <typename T>
337	static T Make();
338
339	// An overload be selected when implicit conversion from T to To is possible.
340	template <typename T, typename = decltype(Accept<To>(Make<T>()))>
341	static std::true_type TestImplicitConversion(int);
342
343	// A fallback overload selected in all other cases.
344	template <typename T>
345	static std::false_type TestImplicitConversion(...);
346
347	public:
348	using type = decltype(TestImplicitConversion<From>(`0`));
349	static constexpr bool value = type::value;
350	};
351
352	// Like std::invoke_result_t from C++17, but works only for objects with call
353	// operators (not e.g. member function pointers, which we don't need specific
354	// support for in OnceAction because std::function deals with them).
355	template <typename F, typename... Args>
356	using call_result_t = decltype(std::declval<F>()(std::declval<Args>()...));
357
358	template <typename Void, typename R, typename F, typename... Args>
359	struct is_callable_r_impl : std::false_type {};
360
361	// Specialize the struct for those template arguments where call_result_t is
362	// well-formed. When it's not, the generic template above is chosen, resulting
363	// in std::false_type.
364	template <typename R, typename F, typename... Args>
365	struct is_callable_r_impl<void_t<call_result_t<F, Args...>>, R, F, Args...>
366	: std::conditional<
367	std::is_void<R>::value, //
368	std::true_type, //
369	is_implicitly_convertible<call_result_t<F, Args...>, R>>::type {};
370
371	// Like std::is_invocable_r from C++17, but works only for objects with call
372	// operators. See the note on call_result_t.
373	template <typename R, typename F, typename... Args>
374	using is_callable_r = is_callable_r_impl<void, R, F, Args...>;
375
376	// Like std::as_const from C++17.
377	template <typename T>
378	typename std::add_const<T>::type& as_const(T& t) {
379	return t;
380	}
381
382	} // namespace internal
383
384	// Specialized for function types below.
385	template <typename F>
386	class OnceAction;
387
388	// An action that can only be used once.
389	//
390	// This is accepted by WillOnce, which doesn't require the underlying action to
391	// be copy-constructible (only move-constructible), and promises to invoke it as
392	// an rvalue reference. This allows the action to work with move-only types like
393	// std::move_only_function in a type-safe manner.
394	//
395	// For example:
396	//
397	// // Assume we have some API that needs to accept a unique pointer to some
398	// // non-copyable object Foo.
399	// void AcceptUniquePointer(std::unique_ptr<Foo> foo);
400	//
401	// // We can define an action that provides a Foo to that API. Because It
402	// // has to give away its unique pointer, it must not be called more than
403	// // once, so its call operator is &&-qualified.
404	// struct ProvideFoo {
405	// std::unique_ptr<Foo> foo;
406	//
407	// void operator()() && {
408	// AcceptUniquePointer(std::move(Foo));
409	// }
410	// };
411	//
412	// // This action can be used with WillOnce.
413	// EXPECT_CALL(mock, Call)
414	// .WillOnce(ProvideFoo{std::make_unique<Foo>(...)});
415	//
416	// // But a call to WillRepeatedly will fail to compile. This is correct,
417	// // since the action cannot correctly be used repeatedly.
418	// EXPECT_CALL(mock, Call)
419	// .WillRepeatedly(ProvideFoo{std::make_unique<Foo>(...)});
420	//
421	// A less-contrived example would be an action that returns an arbitrary type,
422	// whose &&-qualified call operator is capable of dealing with move-only types.
423	template <typename Result, typename... Args>
424	class OnceAction<Result(Args...)> final {
425	private:
426	// True iff we can use the given callable type (or lvalue reference) directly
427	// via StdFunctionAdaptor.
428	template <typename Callable>
429	using IsDirectlyCompatible = internal::conjunction<
430	// It must be possible to capture the callable in StdFunctionAdaptor.
431	std::is_constructible<typename std::decay<Callable>::type, Callable>,
432	// The callable must be compatible with our signature.
433	internal::is_callable_r<Result, typename std::decay<Callable>::type,
434	Args...>>;
435
436	// True iff we can use the given callable type via StdFunctionAdaptor once we
437	// ignore incoming arguments.
438	template <typename Callable>
439	using IsCompatibleAfterIgnoringArguments = internal::conjunction<
440	// It must be possible to capture the callable in a lambda.
441	std::is_constructible<typename std::decay<Callable>::type, Callable>,
442	// The callable must be invocable with zero arguments, returning something
443	// convertible to Result.
444	internal::is_callable_r<Result, typename std::decay<Callable>::type>>;
445
446	public:
447	// Construct from a callable that is directly compatible with our mocked
448	// signature: it accepts our function type's arguments and returns something
449	// convertible to our result type.
450	template <typename Callable,
451	typename std::enable_if<
452	internal::conjunction<
453	// Teach clang on macOS that we're not talking about a
454	// copy/move constructor here. Otherwise it gets confused
455	// when checking the is_constructible requirement of our
456	// traits above.
457	internal::negation<std::is_same<
458	OnceAction, typename std::decay<Callable>::type>>,
459	IsDirectlyCompatible<Callable>> //
460	::value,
461	int>::type = `0`>
462	OnceAction(Callable&& callable) // NOLINT
463	: function_(StdFunctionAdaptor<typename std::decay<Callable>::type>(
464	{}, std::forward<Callable>(callable))) {}
465
466	// As above, but for a callable that ignores the mocked function's arguments.
467	template <typename Callable,
468	typename std::enable_if<
469	internal::conjunction<
470	// Teach clang on macOS that we're not talking about a
471	// copy/move constructor here. Otherwise it gets confused
472	// when checking the is_constructible requirement of our
473	// traits above.
474	internal::negation<std::is_same<
475	OnceAction, typename std::decay<Callable>::type>>,
476	// Exclude callables for which the overload above works.
477	// We'd rather provide the arguments if possible.
478	internal::negation<IsDirectlyCompatible<Callable>>,
479	IsCompatibleAfterIgnoringArguments<Callable>>::value,
480	int>::type = `0`>
481	OnceAction(Callable&& callable) // NOLINT
482	// Call the constructor above with a callable
483	// that ignores the input arguments.
484	: OnceAction(IgnoreIncomingArguments<typename std::decay<Callable>::type>{
485	std::forward<Callable>(callable)}) {}
486
487	// We are naturally copyable because we store only an std::function, but
488	// semantically we should not be copyable.
489	OnceAction(const OnceAction&) = delete;
490	OnceAction& operator=(const OnceAction&) = delete;
491	OnceAction(OnceAction&&) = default;
492
493	// Invoke the underlying action callable with which we were constructed,
494	// handing it the supplied arguments.
495	Result Call(Args... args) && {
496	return function_(std::forward<Args>(args)...);
497	}
498
499	private:
500	// An adaptor that wraps a callable that is compatible with our signature and
501	// being invoked as an rvalue reference so that it can be used as an
502	// StdFunctionAdaptor. This throws away type safety, but that's fine because
503	// this is only used by WillOnce, which we know calls at most once.
504	//
505	// Once we have something like std::move_only_function from C++23, we can do
506	// away with this.
507	template <typename Callable>
508	class StdFunctionAdaptor final {
509	public:
510	// A tag indicating that the (otherwise universal) constructor is accepting
511	// the callable itself, instead of e.g. stealing calls for the move
512	// constructor.
513	struct CallableTag final {};
514
515	template <typename F>
516	explicit StdFunctionAdaptor(CallableTag, F&& callable)
517	: callable_(std::make_shared<Callable>(std::forward<F>(callable))) {}
518
519	// Rather than explicitly returning Result, we return whatever the wrapped
520	// callable returns. This allows for compatibility with existing uses like
521	// the following, when the mocked function returns void:
522	//
523	// EXPECT_CALL(mock_fn_, Call)
524	// .WillOnce([&] {
525	// [...]
526	// return 0;
527	// });
528	//
529	// Such a callable can be turned into std::function<void()>. If we use an
530	// explicit return type of Result here then it doesn't* work with*
531	// std::function, because we'll get a "void function should not return a
532	// value" error.
533	//
534	// We need not worry about incompatible result types because the SFINAE on
535	// OnceAction already checks this for us. std::is_invocable_r_v itself makes
536	// the same allowance for void result types.
537	template <typename... ArgRefs>
538	internal::call_result_t<Callable, ArgRefs...> operator()(
539	ArgRefs&&... args) const {
540	return std::move(*callable_)(std::forward<ArgRefs>(args)...);
541	}
542
543	private:
544	// We must put the callable on the heap so that we are copyable, which
545	// std::function needs.
546	std::shared_ptr<Callable> callable_;
547	};
548
549	// An adaptor that makes a callable that accepts zero arguments callable with
550	// our mocked arguments.
551	template <typename Callable>
552	struct IgnoreIncomingArguments {
553	internal::call_result_t<Callable> operator()(Args&&...) {
554	return std::move(callable)();
555	}
556
557	Callable callable;
558	};
559
560	std::function<Result(Args...)> function_;
561	};
562
563	// When an unexpected function call is encountered, Google Mock will
564	// let it return a default value if the user has specified one for its
565	// return type, or if the return type has a built-in default value;
566	// otherwise Google Mock won't know what value to return and will have
567	// to abort the process.
568	//
569	// The DefaultValue<T> class allows a user to specify the
570	// default value for a type T that is both copyable and publicly
571	// destructible (i.e. anything that can be used as a function return
572	// type). The usage is:
573	//
574	// // Sets the default value for type T to be foo.
575	// DefaultValue<T>::Set(foo);
576	template <typename T>
577	class DefaultValue {
578	public:
579	// Sets the default value for type T; requires T to be
580	// copy-constructable and have a public destructor.
581	static void Set(T x) {
582	delete producer_;
583	producer_ = new FixedValueProducer(x);
584	}
585
586	// Provides a factory function to be called to generate the default value.
587	// This method can be used even if T is only move-constructible, but it is not
588	// limited to that case.
589	typedef T (*FactoryFunction)();
590	static void SetFactory(FactoryFunction factory) {
591	delete producer_;
592	producer_ = new FactoryValueProducer(factory);
593	}
594
595	// Unsets the default value for type T.
596	static void Clear() {
597	delete producer_;
598	producer_ = nullptr;
599	}
600
601	// Returns true if and only if the user has set the default value for type T.
602	static bool IsSet() { return producer_ != nullptr; }
603
604	// Returns true if T has a default return value set by the user or there
605	// exists a built-in default value.
606	static bool Exists() {
607	return IsSet() \|\| internal::BuiltInDefaultValue<T>::Exists();
608	}
609
610	// Returns the default value for type T if the user has set one;
611	// otherwise returns the built-in default value. Requires that Exists()
612	// is true, which ensures that the return value is well-defined.
613	static T Get() {
614	return producer_ == nullptr ? internal::BuiltInDefaultValue<T>::Get()
615	: producer_->Produce();
616	}
617
618	private:
619	class ValueProducer {
620	public:
621	virtual ~ValueProducer() = default;
622	virtual T Produce() = `0`;
623	};
624
625	class FixedValueProducer : public ValueProducer {
626	public:
627	explicit FixedValueProducer(T value) : value_(value) {}
628	T Produce() override { return value_; }
629
630	private:
631	const T value_;
632	FixedValueProducer(const FixedValueProducer&) = delete;
633	FixedValueProducer& operator=(const FixedValueProducer&) = delete;
634	};
635
636	class FactoryValueProducer : public ValueProducer {
637	public:
638	explicit FactoryValueProducer(FactoryFunction factory)
639	: factory_(factory) {}
640	T Produce() override { return factory_(); }
641
642	private:
643	const FactoryFunction factory_;
644	FactoryValueProducer(const FactoryValueProducer&) = delete;
645	FactoryValueProducer& operator=(const FactoryValueProducer&) = delete;
646	};
647
648	static ValueProducer* producer_;
649	};
650
651	// This partial specialization allows a user to set default values for
652	// reference types.
653	template <typename T>
654	class DefaultValue<T&> {
655	public:
656	// Sets the default value for type T&.
657	static void Set(T& x) { // NOLINT
658	address_ = &x;
659	}
660
661	// Unsets the default value for type T&.
662	static void Clear() { address_ = nullptr; }
663
664	// Returns true if and only if the user has set the default value for type T&.
665	static bool IsSet() { return address_ != nullptr; }
666
667	// Returns true if T has a default return value set by the user or there
668	// exists a built-in default value.
669	static bool Exists() {
670	return IsSet() \|\| internal::BuiltInDefaultValue<T&>::Exists();
671	}
672
673	// Returns the default value for type T& if the user has set one;
674	// otherwise returns the built-in default value if there is one;
675	// otherwise aborts the process.
676	static T& Get() {
677	return address_ == nullptr ? internal::BuiltInDefaultValue<T&>::Get()
678	: *address_;
679	}
680
681	private:
682	static T* address_;
683	};
684
685	// This specialization allows DefaultValue<void>::Get() to
686	// compile.
687	template <>
688	class DefaultValue<void> {
689	public:
690	static bool Exists() { return true; }
691	static void Get() {}
692	};
693
694	// Points to the user-set default value for type T.
695	template <typename T>
696	typename DefaultValue<T>::ValueProducer* DefaultValue<T>::producer_ = nullptr;
697
698	// Points to the user-set default value for type T&.
699	template <typename T>
700	T* DefaultValue<T&>::address_ = nullptr;
701
702	// Implement this interface to define an action for function type F.
703	template <typename F>
704	class ActionInterface {
705	public:
706	typedef typename internal::Function<F>::Result Result;
707	typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
708
709	ActionInterface() = default;
710	virtual ~ActionInterface() = default;
711
712	// Performs the action. This method is not const, as in general an
713	// action can have side effects and be stateful. For example, a
714	// get-the-next-element-from-the-collection action will need to
715	// remember the current element.
716	virtual Result Perform(const ArgumentTuple& args) = `0`;
717
718	private:
719	ActionInterface(const ActionInterface&) = delete;
720	ActionInterface& operator=(const ActionInterface&) = delete;
721	};
722
723	template <typename F>
724	class Action;
725
726	// An Action<R(Args...)> is a copyable and IMMUTABLE (except by assignment)
727	// object that represents an action to be taken when a mock function of type
728	// R(Args...) is called. The implementation of Action<T> is just a
729	// std::shared_ptr to const ActionInterface<T>. Don't inherit from Action! You
730	// can view an object implementing ActionInterface<F> as a concrete action
731	// (including its current state), and an Action<F> object as a handle to it.
732	template <typename R, typename... Args>
733	class Action<R(Args...)> {
734	private:
735	using F = R(Args...);
736
737	// Adapter class to allow constructing Action from a legacy ActionInterface.
738	// New code should create Actions from functors instead.
739	struct ActionAdapter {
740	// Adapter must be copyable to satisfy std::function requirements.
741	::std::shared_ptr<ActionInterface<F>> impl_;
742
743	template <typename... InArgs>
744	typename internal::Function<F>::Result operator()(InArgs&&... args) {
745	return impl_->Perform(
746	::std::forward_as_tuple(::std::forward<InArgs>(args)...));
747	}
748	};
749
750	template <typename G>
751	using IsCompatibleFunctor = std::is_constructible<std::function<F>, G>;
752
753	public:
754	typedef typename internal::Function<F>::Result Result;
755	typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
756
757	// Constructs a null Action. Needed for storing Action objects in
758	// STL containers.
759	Action() = default;
760
761	// Construct an Action from a specified callable.
762	// This cannot take std::function directly, because then Action would not be
763	// directly constructible from lambda (it would require two conversions).
764	template <
765	typename G,
766	typename = typename std::enable_if<internal::disjunction<
767	IsCompatibleFunctor<G>, std::is_constructible<std::function<Result()>,
768	G>>::value>::type>
769	Action(G&& fun) { // NOLINT
770	Init(::std::forward<G>(fun), IsCompatibleFunctor<G>());
771	}
772
773	// Constructs an Action from its implementation.
774	explicit Action(ActionInterface<F>* impl)
775	: fun_(ActionAdapter{::std::shared_ptr<ActionInterface<F>>(impl)}) {}
776
777	// This constructor allows us to turn an Action<Func> object into an
778	// Action<F>, as long as F's arguments can be implicitly converted
779	// to Func's and Func's return type can be implicitly converted to F's.
780	template <typename Func>
781	Action(const Action<Func>& action) // NOLINT
782	: fun_(action.fun_) {}
783
784	// Returns true if and only if this is the DoDefault() action.
785	bool IsDoDefault() const { return fun_ == nullptr; }
786
787	// Performs the action. Note that this method is const even though
788	// the corresponding method in ActionInterface is not. The reason
789	// is that a const Action<F> means that it cannot be re-bound to
790	// another concrete action, not that the concrete action it binds to
791	// cannot change state. (Think of the difference between a const
792	// pointer and a pointer to const.)
793	Result Perform(ArgumentTuple args) const {
794	if (IsDoDefault()) {
795	internal::IllegalDoDefault(__FILE__, __LINE__);
796	}
797	return internal::Apply(fun_, ::std::move(args));
798	}
799
800	// An action can be used as a OnceAction, since it's obviously safe to call it
801	// once.
802	operator OnceAction<F>() const { // NOLINT
803	// Return a OnceAction-compatible callable that calls Perform with the
804	// arguments it is provided. We could instead just return fun_, but then
805	// we'd need to handle the IsDoDefault() case separately.
806	struct OA {
807	Action<F> action;
808
809	R operator()(Args... args) && {
810	return action.Perform(
811	args: std::forward_as_tuple(std::forward<Args>(args)...));
812	}
813	};
814
815	return OA{*this};
816	}
817
818	private:
819	template <typename G>
820	friend class Action;
821
822	template <typename G>
823	void Init(G&& g, ::std::true_type) {
824	fun_ = ::std::forward<G>(g);
825	}
826
827	template <typename G>
828	void Init(G&& g, ::std::false_type) {
829	fun_ = IgnoreArgs<typename ::std::decay<G>::type>{::std::forward<G>(g)};
830	}
831
832	template <typename FunctionImpl>
833	struct IgnoreArgs {
834	template <typename... InArgs>
835	Result operator()(const InArgs&...) const {
836	return function_impl();
837	}
838	template <typename... InArgs>
839	Result operator()(const InArgs&...) {
840	return function_impl();
841	}
842
843	FunctionImpl function_impl;
844	};
845
846	// fun_ is an empty function if and only if this is the DoDefault() action.
847	::std::function<F> fun_;
848	};
849
850	// The PolymorphicAction class template makes it easy to implement a
851	// polymorphic action (i.e. an action that can be used in mock
852	// functions of than one type, e.g. Return()).
853	//
854	// To define a polymorphic action, a user first provides a COPYABLE
855	// implementation class that has a Perform() method template:
856	//
857	// class FooAction {
858	// public:
859	// template <typename Result, typename ArgumentTuple>
860	// Result Perform(const ArgumentTuple& args) const {
861	// // Processes the arguments and returns a result, using
862	// // std::get<N>(args) to get the N-th (0-based) argument in the tuple.
863	// }
864	// ...
865	// };
866	//
867	// Then the user creates the polymorphic action using
868	// MakePolymorphicAction(object) where object has type FooAction. See
869	// the definition of Return(void) and SetArgumentPointee<N>(value) for
870	// complete examples.
871	template <typename Impl>
872	class PolymorphicAction {
873	public:
874	explicit PolymorphicAction(const Impl& impl) : impl_(impl) {}
875
876	template <typename F>
877	operator Action<F>() const {
878	return Action<F>(new MonomorphicImpl<F>(impl_));
879	}
880
881	private:
882	template <typename F>
883	class MonomorphicImpl : public ActionInterface<F> {
884	public:
885	typedef typename internal::Function<F>::Result Result;
886	typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
887
888	explicit MonomorphicImpl(const Impl& impl) : impl_(impl) {}
889
890	Result Perform(const ArgumentTuple& args) override {
891	return impl_.template Perform<Result>(args);
892	}
893
894	private:
895	Impl impl_;
896	};
897
898	Impl impl_;
899	};
900
901	// Creates an Action from its implementation and returns it. The
902	// created Action object owns the implementation.
903	template <typename F>
904	Action<F> MakeAction(ActionInterface<F>* impl) {
905	return Action<F>(impl);
906	}
907
908	// Creates a polymorphic action from its implementation. This is
909	// easier to use than the PolymorphicAction<Impl> constructor as it
910	// doesn't require you to explicitly write the template argument, e.g.
911	//
912	// MakePolymorphicAction(foo);
913	// vs
914	// PolymorphicAction<TypeOfFoo>(foo);
915	template <typename Impl>
916	inline PolymorphicAction<Impl> MakePolymorphicAction(const Impl& impl) {
917	return PolymorphicAction<Impl>(impl);
918	}
919
920	namespace internal {
921
922	// Helper struct to specialize ReturnAction to execute a move instead of a copy
923	// on return. Useful for move-only types, but could be used on any type.
924	template <typename T>
925	struct ByMoveWrapper {
926	explicit ByMoveWrapper(T value) : payload(std::move(value)) {}
927	T payload;
928	};
929
930	// The general implementation of Return(R). Specializations follow below.
931	template <typename R>
932	class ReturnAction final {
933	public:
934	explicit ReturnAction(R value) : value_(std::move(value)) {}
935
936	template <typename U, typename... Args,
937	typename = typename std::enable_if<conjunction<
938	// See the requirements documented on Return.
939	negation<std::is_same<void, U>>, //
940	negation<std::is_reference<U>>, //
941	std::is_convertible<R, U>, //
942	std::is_move_constructible<U>>::value>::type>
943	operator OnceAction<U(Args...)>() && { // NOLINT
944	return Impl<U>(std::move(value_));
945	}
946
947	template <typename U, typename... Args,
948	typename = typename std::enable_if<conjunction<
949	// See the requirements documented on Return.
950	negation<std::is_same<void, U>>, //
951	negation<std::is_reference<U>>, //
952	std::is_convertible<const R&, U>, //
953	std::is_copy_constructible<U>>::value>::type>
954	operator Action<U(Args...)>() const { // NOLINT
955	return Impl<U>(value_);
956	}
957
958	private:
959	// Implements the Return(x) action for a mock function that returns type U.
960	template <typename U>
961	class Impl final {
962	public:
963	// The constructor used when the return value is allowed to move from the
964	// input value (i.e. we are converting to OnceAction).
965	explicit Impl(R&& input_value)
966	: state_(new State(std::move(input_value))) {}
967
968	// The constructor used when the return value is not allowed to move from
969	// the input value (i.e. we are converting to Action).
970	explicit Impl(const R& input_value) : state_(new State(input_value)) {}
971
972	U operator()() && { return std::move(state_->value); }
973	U operator()() const& { return state_->value; }
974
975	private:
976	// We put our state on the heap so that the compiler-generated copy/move
977	// constructors work correctly even when U is a reference-like type. This is
978	// necessary only because we eagerly create State::value (see the note on
979	// that symbol for details). If we instead had only the input value as a
980	// member then the default constructors would work fine.
981	//
982	// For example, when R is std::string and U is std::string_view, value is a
983	// reference to the string backed by input_value. The copy constructor would
984	// copy both, so that we wind up with a new input_value object (with the
985	// same contents) and a reference to the old* input_value object rather*
986	// than the new one.
987	struct State {
988	explicit State(const R& input_value_in)
989	: input_value(input_value_in),
990	// Make an implicit conversion to Result before initializing the U
991	// object we store, avoiding calling any explicit constructor of U
992	// from R.
993	//
994	// This simulates the language rules: a function with return type U
995	// that does `return R()` requires R to be implicitly convertible to
996	// U, and uses that path for the conversion, even U Result has an
997	// explicit constructor from R.
998	value(ImplicitCast_<U>(internal::as_const(input_value))) {}
999
1000	// As above, but for the case where we're moving from the ReturnAction
1001	// object because it's being used as a OnceAction.
1002	explicit State(R&& input_value_in)
1003	: input_value(std::move(input_value_in)),
1004	// For the same reason as above we make an implicit conversion to U
1005	// before initializing the value.
1006	//
1007	// Unlike above we provide the input value as an rvalue to the
1008	// implicit conversion because this is a OnceAction: it's fine if it
1009	// wants to consume the input value.
1010	value(ImplicitCast_<U>(std::move(input_value))) {}
1011
1012	// A copy of the value originally provided by the user. We retain this in
1013	// addition to the value of the mock function's result type below in case
1014	// the latter is a reference-like type. See the std::string_view example
1015	// in the documentation on Return.
1016	R input_value;
1017
1018	// The value we actually return, as the type returned by the mock function
1019	// itself.
1020	//
1021	// We eagerly initialize this here, rather than lazily doing the implicit
1022	// conversion automatically each time Perform is called, for historical
1023	// reasons: in 2009-11, commit a070cbd91c (Google changelist 13540126)
1024	// made the Action<U()> conversion operator eagerly convert the R value to
1025	// U, but without keeping the R alive. This broke the use case discussed
1026	// in the documentation for Return, making reference-like types such as
1027	// std::string_view not safe to use as U where the input type R is a
1028	// value-like type such as std::string.
1029	//
1030	// The example the commit gave was not very clear, nor was the issue
1031	// thread (https://github.com/google/googlemock/issues/86), but it seems
1032	// the worry was about reference-like input types R that flatten to a
1033	// value-like type U when being implicitly converted. An example of this
1034	// is std::vector<bool>::reference, which is often a proxy type with an
1035	// reference to the underlying vector:
1036	//
1037	// // Helper method: have the mock function return bools according
1038	// // to the supplied script.
1039	// void SetActions(MockFunction<bool(size_t)>& mock,
1040	// const std::vector<bool>& script) {
1041	// for (size_t i = 0; i < script.size(); ++i) {
1042	// EXPECT_CALL(mock, Call(i)).WillOnce(Return(script[i]));
1043	// }
1044	// }
1045	//
1046	// TEST(Foo, Bar) {
1047	// // Set actions using a temporary vector, whose operator[]
1048	// // returns proxy objects that references that will be
1049	// // dangling once the call to SetActions finishes and the
1050	// // vector is destroyed.
1051	// MockFunction<bool(size_t)> mock;
1052	// SetActions(mock, {false, true});
1053	//
1054	// EXPECT_FALSE(mock.AsStdFunction()(0));
1055	// EXPECT_TRUE(mock.AsStdFunction()(1));
1056	// }
1057	//
1058	// This eager conversion helps with a simple case like this, but doesn't
1059	// fully make these types work in general. For example the following still
1060	// uses a dangling reference:
1061	//
1062	// TEST(Foo, Baz) {
1063	// MockFunction<std::vector<std::string>()> mock;
1064	//
1065	// // Return the same vector twice, and then the empty vector
1066	// // thereafter.
1067	// auto action = Return(std::initializer_list<std::string>{
1068	// "taco", "burrito",
1069	// });
1070	//
1071	// EXPECT_CALL(mock, Call)
1072	// .WillOnce(action)
1073	// .WillOnce(action)
1074	// .WillRepeatedly(Return(std::vector<std::string>{}));
1075	//
1076	// EXPECT_THAT(mock.AsStdFunction()(),
1077	// ElementsAre("taco", "burrito"));
1078	// EXPECT_THAT(mock.AsStdFunction()(),
1079	// ElementsAre("taco", "burrito"));
1080	// EXPECT_THAT(mock.AsStdFunction()(), IsEmpty());
1081	// }
1082	//
1083	U value;
1084	};
1085
1086	const std::shared_ptr<State> state_;
1087	};
1088
1089	R value_;
1090	};
1091
1092	// A specialization of ReturnAction<R> when R is ByMoveWrapper<T> for some T.
1093	//
1094	// This version applies the type system-defeating hack of moving from T even in
1095	// the const call operator, checking at runtime that it isn't called more than
1096	// once, since the user has declared their intent to do so by using ByMove.
1097	template <typename T>
1098	class ReturnAction<ByMoveWrapper<T>> final {
1099	public:
1100	explicit ReturnAction(ByMoveWrapper<T> wrapper)
1101	: state_(new State(std::move(wrapper.payload))) {}
1102
1103	T operator()() const {
1104	GTEST_CHECK_(!state_->called)
1105	<< "A ByMove() action must be performed at most once.";
1106
1107	state_->called = true;
1108	return std::move(state_->value);
1109	}
1110
1111	private:
1112	// We store our state on the heap so that we are copyable as required by
1113	// Action, despite the fact that we are stateful and T may not be copyable.
1114	struct State {
1115	explicit State(T&& value_in) : value(std::move(value_in)) {}
1116
1117	T value;
1118	bool called = false;
1119	};
1120
1121	const std::shared_ptr<State> state_;
1122	};
1123
1124	// Implements the ReturnNull() action.
1125	class ReturnNullAction {
1126	public:
1127	// Allows ReturnNull() to be used in any pointer-returning function. In C++11
1128	// this is enforced by returning nullptr, and in non-C++11 by asserting a
1129	// pointer type on compile time.
1130	template <typename Result, typename ArgumentTuple>
1131	static Result Perform(const ArgumentTuple&) {
1132	return nullptr;
1133	}
1134	};
1135
1136	// Implements the Return() action.
1137	class ReturnVoidAction {
1138	public:
1139	// Allows Return() to be used in any void-returning function.
1140	template <typename Result, typename ArgumentTuple>
1141	static void Perform(const ArgumentTuple&) {
1142	static_assert(std::is_void<Result>::value, "Result should be void.");
1143	}
1144	};
1145
1146	// Implements the polymorphic ReturnRef(x) action, which can be used
1147	// in any function that returns a reference to the type of x,
1148	// regardless of the argument types.
1149	template <typename T>
1150	class ReturnRefAction {
1151	public:
1152	// Constructs a ReturnRefAction object from the reference to be returned.
1153	explicit ReturnRefAction(T& ref) : ref_(ref) {} // NOLINT
1154
1155	// This template type conversion operator allows ReturnRef(x) to be
1156	// used in ANY function that returns a reference to x's type.
1157	template <typename F>
1158	operator Action<F>() const {
1159	typedef typename Function<F>::Result Result;
1160	// Asserts that the function return type is a reference. This
1161	// catches the user error of using ReturnRef(x) when Return(x)
1162	// should be used, and generates some helpful error message.
1163	static_assert(std::is_reference<Result>::value,
1164	"use Return instead of ReturnRef to return a value");
1165	return Action<F>(new Impl<F>(ref_));
1166	}
1167
1168	private:
1169	// Implements the ReturnRef(x) action for a particular function type F.
1170	template <typename F>
1171	class Impl : public ActionInterface<F> {
1172	public:
1173	typedef typename Function<F>::Result Result;
1174	typedef typename Function<F>::ArgumentTuple ArgumentTuple;
1175
1176	explicit Impl(T& ref) : ref_(ref) {} // NOLINT
1177
1178	Result Perform(const ArgumentTuple&) override { return ref_; }
1179
1180	private:
1181	T& ref_;
1182	};
1183
1184	T& ref_;
1185	};
1186
1187	// Implements the polymorphic ReturnRefOfCopy(x) action, which can be
1188	// used in any function that returns a reference to the type of x,
1189	// regardless of the argument types.
1190	template <typename T>
1191	class ReturnRefOfCopyAction {
1192	public:
1193	// Constructs a ReturnRefOfCopyAction object from the reference to
1194	// be returned.
1195	explicit ReturnRefOfCopyAction(const T& value) : value_(value) {} // NOLINT
1196
1197	// This template type conversion operator allows ReturnRefOfCopy(x) to be
1198	// used in ANY function that returns a reference to x's type.
1199	template <typename F>
1200	operator Action<F>() const {
1201	typedef typename Function<F>::Result Result;
1202	// Asserts that the function return type is a reference. This
1203	// catches the user error of using ReturnRefOfCopy(x) when Return(x)
1204	// should be used, and generates some helpful error message.
1205	static_assert(std::is_reference<Result>::value,
1206	"use Return instead of ReturnRefOfCopy to return a value");
1207	return Action<F>(new Impl<F>(value_));
1208	}
1209
1210	private:
1211	// Implements the ReturnRefOfCopy(x) action for a particular function type F.
1212	template <typename F>
1213	class Impl : public ActionInterface<F> {
1214	public:
1215	typedef typename Function<F>::Result Result;
1216	typedef typename Function<F>::ArgumentTuple ArgumentTuple;
1217
1218	explicit Impl(const T& value) : value_(value) {} // NOLINT
1219
1220	Result Perform(const ArgumentTuple&) override { return value_; }
1221
1222	private:
1223	T value_;
1224	};
1225
1226	const T value_;
1227	};
1228
1229	// Implements the polymorphic ReturnRoundRobin(v) action, which can be
1230	// used in any function that returns the element_type of v.
1231	template <typename T>
1232	class ReturnRoundRobinAction {
1233	public:
1234	explicit ReturnRoundRobinAction(std::vector<T> values) {
1235	GTEST_CHECK_(!values.empty())
1236	<< "ReturnRoundRobin requires at least one element.";
1237	state_->values = std::move(values);
1238	}
1239
1240	template <typename... Args>
1241	T operator()(Args&&...) const {
1242	return state_->Next();
1243	}
1244
1245	private:
1246	struct State {
1247	T Next() {
1248	T ret_val = values[i++];
1249	if (i == values.size()) i = `0`;
1250	return ret_val;
1251	}
1252
1253	std::vector<T> values;
1254	size_t i = `0`;
1255	};
1256	std::shared_ptr<State> state_ = std::make_shared<State>();
1257	};
1258
1259	// Implements the polymorphic DoDefault() action.
1260	class DoDefaultAction {
1261	public:
1262	// This template type conversion operator allows DoDefault() to be
1263	// used in any function.
1264	template <typename F>
1265	operator Action<F>() const {
1266	return Action<F>();
1267	} // NOLINT
1268	};
1269
1270	// Implements the Assign action to set a given pointer referent to a
1271	// particular value.
1272	template <typename T1, typename T2>
1273	class AssignAction {
1274	public:
1275	AssignAction(T1* ptr, T2 value) : ptr_(ptr), value_(value) {}
1276
1277	template <typename Result, typename ArgumentTuple>
1278	void Perform(const ArgumentTuple& / args /) const {
1279	*ptr_ = value_;
1280	}
1281
1282	private:
1283	T1* const ptr_;
1284	const T2 value_;
1285	};
1286
1287	#ifndef GTEST_OS_WINDOWS_MOBILE
1288
1289	// Implements the SetErrnoAndReturn action to simulate return from
1290	// various system calls and libc functions.
1291	template <typename T>
1292	class SetErrnoAndReturnAction {
1293	public:
1294	SetErrnoAndReturnAction(int errno_value, T result)
1295	: errno_(errno_value), result_(result) {}
1296	template <typename Result, typename ArgumentTuple>
1297	Result Perform(const ArgumentTuple& / args /) const {
1298	errno = errno_;
1299	return result_;
1300	}
1301
1302	private:
1303	const int errno_;
1304	const T result_;
1305	};
1306
1307	#endif // !GTEST_OS_WINDOWS_MOBILE
1308
1309	// Implements the SetArgumentPointee<N>(x) action for any function
1310	// whose N-th argument (0-based) is a pointer to x's type.
1311	template <size_t N, typename A, typename = void>
1312	struct SetArgumentPointeeAction {
1313	A value;
1314
1315	template <typename... Args>
1316	void operator()(const Args&... args) const {
1317	*::std::get<N>(std::tie(args...)) = value;
1318	}
1319	};
1320
1321	// Implements the Invoke(object_ptr, &Class::Method) action.
1322	template <class Class, typename MethodPtr>
1323	struct InvokeMethodAction {
1324	Class* const obj_ptr;
1325	const MethodPtr method_ptr;
1326
1327	template <typename... Args>
1328	auto operator()(Args&&... args) const
1329	-> decltype((obj_ptr->*method_ptr)(std::forward<Args>(args)...)) {
1330	return (obj_ptr->*method_ptr)(std::forward<Args>(args)...);
1331	}
1332	};
1333
1334	// Implements the InvokeWithoutArgs(f) action. The template argument
1335	// FunctionImpl is the implementation type of f, which can be either a
1336	// function pointer or a functor. InvokeWithoutArgs(f) can be used as an
1337	// Action<F> as long as f's type is compatible with F.
1338	template <typename FunctionImpl>
1339	struct InvokeWithoutArgsAction {
1340	FunctionImpl function_impl;
1341
1342	// Allows InvokeWithoutArgs(f) to be used as any action whose type is
1343	// compatible with f.
1344	template <typename... Args>
1345	auto operator()(const Args&...) -> decltype(function_impl()) {
1346	return function_impl();
1347	}
1348	};
1349
1350	// Implements the InvokeWithoutArgs(object_ptr, &Class::Method) action.
1351	template <class Class, typename MethodPtr>
1352	struct InvokeMethodWithoutArgsAction {
1353	Class* const obj_ptr;
1354	const MethodPtr method_ptr;
1355
1356	using ReturnType =
1357	decltype((std::declval<Class>()->std::declval<MethodPtr>())());
1358
1359	template <typename... Args>
1360	ReturnType operator()(const Args&...) const {
1361	return (obj_ptr->*method_ptr)();
1362	}
1363	};
1364
1365	// Implements the IgnoreResult(action) action.
1366	template <typename A>
1367	class IgnoreResultAction {
1368	public:
1369	explicit IgnoreResultAction(const A& action) : action_(action) {}
1370
1371	template <typename F>
1372	operator Action<F>() const {
1373	// Assert statement belongs here because this is the best place to verify
1374	// conditions on F. It produces the clearest error messages
1375	// in most compilers.
1376	// Impl really belongs in this scope as a local class but can't
1377	// because MSVC produces duplicate symbols in different translation units
1378	// in this case. Until MS fixes that bug we put Impl into the class scope
1379	// and put the typedef both here (for use in assert statement) and
1380	// in the Impl class. But both definitions must be the same.
1381	typedef typename internal::Function<F>::Result Result;
1382
1383	// Asserts at compile time that F returns void.
1384	static_assert(std::is_void<Result>::value, "Result type should be void.");
1385
1386	return Action<F>(new Impl<F>(action_));
1387	}
1388
1389	private:
1390	template <typename F>
1391	class Impl : public ActionInterface<F> {
1392	public:
1393	typedef typename internal::Function<F>::Result Result;
1394	typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
1395
1396	explicit Impl(const A& action) : action_(action) {}
1397
1398	void Perform(const ArgumentTuple& args) override {
1399	// Performs the action and ignores its result.
1400	action_.Perform(args);
1401	}
1402
1403	private:
1404	// Type OriginalFunction is the same as F except that its return
1405	// type is IgnoredValue.
1406	typedef
1407	typename internal::Function<F>::MakeResultIgnoredValue OriginalFunction;
1408
1409	const Action<OriginalFunction> action_;
1410	};
1411
1412	const A action_;
1413	};
1414
1415	template <typename InnerAction, size_t... I>
1416	struct WithArgsAction {
1417	InnerAction inner_action;
1418
1419	// The signature of the function as seen by the inner action, given an out
1420	// action with the given result and argument types.
1421	template <typename R, typename... Args>
1422	using InnerSignature =
1423	R(typename std::tuple_element<I, std::tuple<Args...>>::type...);
1424
1425	// Rather than a call operator, we must define conversion operators to
1426	// particular action types. This is necessary for embedded actions like
1427	// DoDefault(), which rely on an action conversion operators rather than
1428	// providing a call operator because even with a particular set of arguments
1429	// they don't have a fixed return type.
1430
1431	template <
1432	typename R, typename... Args,
1433	typename std::enable_if<
1434	std::is_convertible<InnerAction,
1435	// Unfortunately we can't use the InnerSignature
1436	// alias here; MSVC complains about the I
1437	// parameter pack not being expanded (error C3520)
1438	// despite it being expanded in the type alias.
1439	// TupleElement is also an MSVC workaround.
1440	// See its definition for details.
1441	OnceAction<R(internal::TupleElement<
1442	I, std::tuple<Args...>>...)>>::value,
1443	int>::type = `0`>
1444	operator OnceAction<R(Args...)>() && { // NOLINT
1445	struct OA {
1446	OnceAction<InnerSignature<R, Args...>> inner_action;
1447
1448	R operator()(Args&&... args) && {
1449	return std::move(inner_action)
1450	.Call(std::get<I>(
1451	std::forward_as_tuple(std::forward<Args>(args)...))...);
1452	}
1453	};
1454
1455	return OA{std::move(inner_action)};
1456	}
1457
1458	// As above, but in the case where we want to create a OnceAction from a const
1459	// WithArgsAction. This is fine as long as the inner action doesn't need to
1460	// move any of its state to create a OnceAction.
1461	template <
1462	typename R, typename... Args,
1463	typename std::enable_if<
1464	std::is_convertible<const InnerAction&,
1465	OnceAction<R(internal::TupleElement<
1466	I, std::tuple<Args...>>...)>>::value,
1467	int>::type = `0`>
1468	operator OnceAction<R(Args...)>() const& { // NOLINT
1469	struct OA {
1470	OnceAction<InnerSignature<R, Args...>> inner_action;
1471
1472	R operator()(Args&&... args) && {
1473	return std::move(inner_action)
1474	.Call(std::get<I>(
1475	std::forward_as_tuple(std::forward<Args>(args)...))...);
1476	}
1477	};
1478
1479	return OA{inner_action};
1480	}
1481
1482	template <
1483	typename R, typename... Args,
1484	typename std::enable_if<
1485	std::is_convertible<const InnerAction&,
1486	// Unfortunately we can't use the InnerSignature
1487	// alias here; MSVC complains about the I
1488	// parameter pack not being expanded (error C3520)
1489	// despite it being expanded in the type alias.
1490	// TupleElement is also an MSVC workaround.
1491	// See its definition for details.
1492	Action<R(internal::TupleElement<
1493	I, std::tuple<Args...>>...)>>::value,
1494	int>::type = `0`>
1495	operator Action<R(Args...)>() const { // NOLINT
1496	Action<InnerSignature<R, Args...>> converted(inner_action);
1497
1498	return [converted](Args&&... args) -> R {
1499	return converted.Perform(std::forward_as_tuple(
1500	std::get<I>(std::forward_as_tuple(std::forward<Args>(args)...))...));
1501	};
1502	}
1503	};
1504
1505	template <typename... Actions>
1506	class DoAllAction;
1507
1508	// Base case: only a single action.
1509	template <typename FinalAction>
1510	class DoAllAction<FinalAction> {
1511	public:
1512	struct UserConstructorTag {};
1513
1514	template <typename T>
1515	explicit DoAllAction(UserConstructorTag, T&& action)
1516	: final_action_(std::forward<T>(action)) {}
1517
1518	// Rather than a call operator, we must define conversion operators to
1519	// particular action types. This is necessary for embedded actions like
1520	// DoDefault(), which rely on an action conversion operators rather than
1521	// providing a call operator because even with a particular set of arguments
1522	// they don't have a fixed return type.
1523
1524	// We support conversion to OnceAction whenever the sub-action does.
1525	template <typename R, typename... Args,
1526	typename std::enable_if<
1527	std::is_convertible<FinalAction, OnceAction<R(Args...)>>::value,
1528	int>::type = `0`>
1529	operator OnceAction<R(Args...)>() && { // NOLINT
1530	return std::move(final_action_);
1531	}
1532
1533	// We also support conversion to OnceAction whenever the sub-action supports
1534	// conversion to Action (since any Action can also be a OnceAction).
1535	template <
1536	typename R, typename... Args,
1537	typename std::enable_if<
1538	conjunction<
1539	negation<
1540	std::is_convertible<FinalAction, OnceAction<R(Args...)>>>,
1541	std::is_convertible<FinalAction, Action<R(Args...)>>>::value,
1542	int>::type = `0`>
1543	operator OnceAction<R(Args...)>() && { // NOLINT
1544	return Action<R(Args...)>(std::move(final_action_));
1545	}
1546
1547	// We support conversion to Action whenever the sub-action does.
1548	template <
1549	typename R, typename... Args,
1550	typename std::enable_if<
1551	std::is_convertible<const FinalAction&, Action<R(Args...)>>::value,
1552	int>::type = `0`>
1553	operator Action<R(Args...)>() const { // NOLINT
1554	return final_action_;
1555	}
1556
1557	private:
1558	FinalAction final_action_;
1559	};
1560
1561	// Recursive case: support N actions by calling the initial action and then
1562	// calling through to the base class containing N-1 actions.
1563	template <typename InitialAction, typename... OtherActions>
1564	class DoAllAction<InitialAction, OtherActions...>
1565	: private DoAllAction<OtherActions...> {
1566	private:
1567	using Base = DoAllAction<OtherActions...>;
1568
1569	// The type of reference that should be provided to an initial action for a
1570	// mocked function parameter of type T.
1571	//
1572	// There are two quirks here:
1573	//
1574	// Unlike most forwarding functions, we pass scalars through by value.*
1575	// This isn't strictly necessary because an lvalue reference would work
1576	// fine too and be consistent with other non-reference types, but it's
1577	// perhaps less surprising.
1578	//
1579	// For example if the mocked function has signature void(int), then it
1580	// might seem surprising for the user's initial action to need to be
1581	// convertible to Action<void(const int&)>. This is perhaps less
1582	// surprising for a non-scalar type where there may be a performance
1583	// impact, or it might even be impossible, to pass by value.
1584	//
1585	// More surprisingly, `const T&` is often not a const reference type.*
1586	// By the reference collapsing rules in C++17 [dcl.ref]/6, if T refers to
1587	// U& or U&& for some non-scalar type U, then InitialActionArgType<T> is
1588	// U&. In other words, we may hand over a non-const reference.
1589	//
1590	// So for example, given some non-scalar type Obj we have the following
1591	// mappings:
1592	//
1593	// T InitialActionArgType<T>
1594	// ------- -----------------------
1595	// Obj const Obj&
1596	// Obj& Obj&
1597	// Obj&& Obj&
1598	// const Obj const Obj&
1599	// const Obj& const Obj&
1600	// const Obj&& const Obj&
1601	//
1602	// In other words, the initial actions get a mutable view of an non-scalar
1603	// argument if and only if the mock function itself accepts a non-const
1604	// reference type. They are never given an rvalue reference to an
1605	// non-scalar type.
1606	//
1607	// This situation makes sense if you imagine use with a matcher that is
1608	// designed to write through a reference. For example, if the caller wants
1609	// to fill in a reference argument and then return a canned value:
1610	//
1611	// EXPECT_CALL(mock, Call)
1612	// .WillOnce(DoAll(SetArgReferee<0>(17), Return(19)));
1613	//
1614	template <typename T>
1615	using InitialActionArgType =
1616	typename std::conditional<std::is_scalar<T>::value, T, const T&>::type;
1617
1618	public:
1619	struct UserConstructorTag {};
1620
1621	template <typename T, typename... U>
1622	explicit DoAllAction(UserConstructorTag, T&& initial_action,
1623	U&&... other_actions)
1624	: Base({}, std::forward<U>(other_actions)...),
1625	initial_action_(std::forward<T>(initial_action)) {}
1626
1627	// We support conversion to OnceAction whenever both the initial action and
1628	// the rest support conversion to OnceAction.
1629	template <
1630	typename R, typename... Args,
1631	typename std::enable_if<
1632	conjunction<std::is_convertible<
1633	InitialAction,
1634	OnceAction<void(InitialActionArgType<Args>...)>>,
1635	std::is_convertible<Base, OnceAction<R(Args...)>>>::value,
1636	int>::type = `0`>
1637	operator OnceAction<R(Args...)>() && { // NOLINT
1638	// Return an action that first calls the initial action with arguments
1639	// filtered through InitialActionArgType, then forwards arguments directly
1640	// to the base class to deal with the remaining actions.
1641	struct OA {
1642	OnceAction<void(InitialActionArgType<Args>...)> initial_action;
1643	OnceAction<R(Args...)> remaining_actions;
1644
1645	R operator()(Args... args) && {
1646	std::move(initial_action)
1647	.Call(static_cast<InitialActionArgType<Args>>(args)...);
1648
1649	return std::move(remaining_actions).Call(std::forward<Args>(args)...);
1650	}
1651	};
1652
1653	return OA{
1654	std::move(initial_action_),
1655	std::move(static_cast<Base&>(*this)),
1656	};
1657	}
1658
1659	// We also support conversion to OnceAction whenever the initial action
1660	// supports conversion to Action (since any Action can also be a OnceAction).
1661	//
1662	// The remaining sub-actions must also be compatible, but we don't need to
1663	// special case them because the base class deals with them.
1664	template <
1665	typename R, typename... Args,
1666	typename std::enable_if<
1667	conjunction<
1668	negation<std::is_convertible<
1669	InitialAction,
1670	OnceAction<void(InitialActionArgType<Args>...)>>>,
1671	std::is_convertible<InitialAction,
1672	Action<void(InitialActionArgType<Args>...)>>,
1673	std::is_convertible<Base, OnceAction<R(Args...)>>>::value,
1674	int>::type = `0`>
1675	operator OnceAction<R(Args...)>() && { // NOLINT
1676	return DoAll(
1677	Action<void(InitialActionArgType<Args>...)>(std::move(initial_action_)),
1678	std::move(static_cast<Base&>(*this)));
1679	}
1680
1681	// We support conversion to Action whenever both the initial action and the
1682	// rest support conversion to Action.
1683	template <
1684	typename R, typename... Args,
1685	typename std::enable_if<
1686	conjunction<
1687	std::is_convertible<const InitialAction&,
1688	Action<void(InitialActionArgType<Args>...)>>,
1689	std::is_convertible<const Base&, Action<R(Args...)>>>::value,
1690	int>::type = `0`>
1691	operator Action<R(Args...)>() const { // NOLINT
1692	// Return an action that first calls the initial action with arguments
1693	// filtered through InitialActionArgType, then forwards arguments directly
1694	// to the base class to deal with the remaining actions.
1695	struct OA {
1696	Action<void(InitialActionArgType<Args>...)> initial_action;
1697	Action<R(Args...)> remaining_actions;
1698
1699	R operator()(Args... args) const {
1700	initial_action.Perform(std::forward_as_tuple(
1701	static_cast<InitialActionArgType<Args>>(args)...));
1702
1703	return remaining_actions.Perform(
1704	std::forward_as_tuple(std::forward<Args>(args)...));
1705	}
1706	};
1707
1708	return OA{
1709	initial_action_,
1710	static_cast<const Base&>(*this),
1711	};
1712	}
1713
1714	private:
1715	InitialAction initial_action_;
1716	};
1717
1718	template <typename T, typename... Params>
1719	struct ReturnNewAction {
1720	T* operator()() const {
1721	return internal::Apply(
1722	[](const Params&... unpacked_params) {
1723	return new T(unpacked_params...);
1724	},
1725	params);
1726	}
1727	std::tuple<Params...> params;
1728	};
1729
1730	template <size_t k>
1731	struct ReturnArgAction {
1732	template <typename... Args,
1733	typename = typename std::enable_if<(k < sizeof...(Args))>::type>
1734	auto operator()(Args&&... args) const -> decltype(std::get<k>(
1735	std::forward_as_tuple(std::forward<Args>(args)...))) {
1736	return std::get<k>(std::forward_as_tuple(std::forward<Args>(args)...));
1737	}
1738	};
1739
1740	template <size_t k, typename Ptr>
1741	struct SaveArgAction {
1742	Ptr pointer;
1743
1744	template <typename... Args>
1745	void operator()(const Args&... args) const {
1746	*pointer = std::get<k>(std::tie(args...));
1747	}
1748	};
1749
1750	template <size_t k, typename Ptr>
1751	struct SaveArgByMoveAction {
1752	Ptr pointer;
1753
1754	template <typename... Args>
1755	void operator()(Args&&... args) const {
1756	*pointer = std::move(std::get<k>(std::tie(args...)));
1757	}
1758	};
1759
1760	template <size_t k, typename Ptr>
1761	struct SaveArgPointeeAction {
1762	Ptr pointer;
1763
1764	template <typename... Args>
1765	void operator()(const Args&... args) const {
1766	pointer = std::get<k>(std::tie(args...));
1767	}
1768	};
1769
1770	template <size_t k, typename T>
1771	struct SetArgRefereeAction {
1772	T value;
1773
1774	template <typename... Args>
1775	void operator()(Args&&... args) const {
1776	using argk_type =
1777	typename ::std::tuple_element<k, std::tuple<Args...>>::type;
1778	static_assert(std::is_lvalue_reference<argk_type>::value,
1779	"Argument must be a reference type.");
1780	std::get<k>(std::tie(args...)) = value;
1781	}
1782	};
1783
1784	template <size_t k, typename I1, typename I2>
1785	struct SetArrayArgumentAction {
1786	I1 first;
1787	I2 last;
1788
1789	template <typename... Args>
1790	void operator()(const Args&... args) const {
1791	auto value = std::get<k>(std::tie(args...));
1792	for (auto it = first; it != last; ++it, (void)++value) {
1793	value = it;
1794	}
1795	}
1796	};
1797
1798	template <size_t k>
1799	struct DeleteArgAction {
1800	template <typename... Args>
1801	void operator()(const Args&... args) const {
1802	delete std::get<k>(std::tie(args...));
1803	}
1804	};
1805
1806	template <typename Ptr>
1807	struct ReturnPointeeAction {
1808	Ptr pointer;
1809	template <typename... Args>
1810	auto operator()(const Args&...) const -> decltype(*pointer) {
1811	return *pointer;
1812	}
1813	};
1814
1815	#if GTEST_HAS_EXCEPTIONS
1816	template <typename T>
1817	struct ThrowAction {
1818	T exception;
1819	// We use a conversion operator to adapt to any return type.
1820	template <typename R, typename... Args>
1821	operator Action<R(Args...)>() const { // NOLINT
1822	T copy = exception;
1823	return [copy](Args...) -> R { throw copy; };
1824	}
1825	};
1826	struct RethrowAction {
1827	std::exception_ptr exception;
1828	template <typename R, typename... Args>
1829	operator Action<R(Args...)>() const { // NOLINT
1830	return [ex = exception](Args...) -> R { std::rethrow_exception(ex); };
1831	}
1832	};
1833	#endif // GTEST_HAS_EXCEPTIONS
1834
1835	} // namespace internal
1836
1837	// An Unused object can be implicitly constructed from ANY value.
1838	// This is handy when defining actions that ignore some or all of the
1839	// mock function arguments. For example, given
1840	//
1841	// MOCK_METHOD3(Foo, double(const string& label, double x, double y));
1842	// MOCK_METHOD3(Bar, double(int index, double x, double y));
1843	//
1844	// instead of
1845	//
1846	// double DistanceToOriginWithLabel(const string& label, double x, double y) {
1847	// return sqrt(xx + yy);
1848	// }
1849	// double DistanceToOriginWithIndex(int index, double x, double y) {
1850	// return sqrt(xx + yy);
1851	// }
1852	// ...
1853	// EXPECT_CALL(mock, Foo("abc", _, _))
1854	// .WillOnce(Invoke(DistanceToOriginWithLabel));
1855	// EXPECT_CALL(mock, Bar(5, _, _))
1856	// .WillOnce(Invoke(DistanceToOriginWithIndex));
1857	//
1858	// you could write
1859	//
1860	// // We can declare any uninteresting argument as Unused.
1861	// double DistanceToOrigin(Unused, double x, double y) {
1862	// return sqrt(xx + yy);
1863	// }
1864	// ...
1865	// EXPECT_CALL(mock, Foo("abc", _, _)).WillOnce(Invoke(DistanceToOrigin));
1866	// EXPECT_CALL(mock, Bar(5, _, _)).WillOnce(Invoke(DistanceToOrigin));
1867	typedef internal::IgnoredValue Unused;
1868
1869	// Creates an action that does actions a1, a2, ..., sequentially in
1870	// each invocation. All but the last action will have a readonly view of the
1871	// arguments.
1872	template <typename... Action>
1873	internal::DoAllAction<typename std::decay<Action>::type...> DoAll(
1874	Action&&... action) {
1875	return internal::DoAllAction<typename std::decay<Action>::type...>(
1876	{}, std::forward<Action>(action)...);
1877	}
1878
1879	// WithArg<k>(an_action) creates an action that passes the k-th
1880	// (0-based) argument of the mock function to an_action and performs
1881	// it. It adapts an action accepting one argument to one that accepts
1882	// multiple arguments. For convenience, we also provide
1883	// WithArgs<k>(an_action) (defined below) as a synonym.
1884	template <size_t k, typename InnerAction>
1885	internal::WithArgsAction<typename std::decay<InnerAction>::type, k> WithArg(
1886	InnerAction&& action) {
1887	return {std::forward<InnerAction>(action)};
1888	}
1889
1890	// WithArgs<N1, N2, ..., Nk>(an_action) creates an action that passes
1891	// the selected arguments of the mock function to an_action and
1892	// performs it. It serves as an adaptor between actions with
1893	// different argument lists.
1894	template <size_t k, size_t... ks, typename InnerAction>
1895	internal::WithArgsAction<typename std::decay<InnerAction>::type, k, ks...>
1896	WithArgs(InnerAction&& action) {
1897	return {std::forward<InnerAction>(action)};
1898	}
1899
1900	// WithoutArgs(inner_action) can be used in a mock function with a
1901	// non-empty argument list to perform inner_action, which takes no
1902	// argument. In other words, it adapts an action accepting no
1903	// argument to one that accepts (and ignores) arguments.
1904	template <typename InnerAction>
1905	internal::WithArgsAction<typename std::decay<InnerAction>::type> WithoutArgs(
1906	InnerAction&& action) {
1907	return {std::forward<InnerAction>(action)};
1908	}
1909
1910	// Creates an action that returns a value.
1911	//
1912	// The returned type can be used with a mock function returning a non-void,
1913	// non-reference type U as follows:
1914	//
1915	// If R is convertible to U and U is move-constructible, then the action can*
1916	// be used with WillOnce.
1917	//
1918	// If const R& is convertible to U and U is copy-constructible, then the*
1919	// action can be used with both WillOnce and WillRepeatedly.
1920	//
1921	// The mock expectation contains the R value from which the U return value is
1922	// constructed (a move/copy of the argument to Return). This means that the R
1923	// value will survive at least until the mock object's expectations are cleared
1924	// or the mock object is destroyed, meaning that U can safely be a
1925	// reference-like type such as std::string_view:
1926	//
1927	// // The mock function returns a view of a copy of the string fed to
1928	// // Return. The view is valid even after the action is performed.
1929	// MockFunction<std::string_view()> mock;
1930	// EXPECT_CALL(mock, Call).WillOnce(Return(std::string("taco")));
1931	// const std::string_view result = mock.AsStdFunction()();
1932	// EXPECT_EQ("taco", result);
1933	//
1934	template <typename R>
1935	internal::ReturnAction<R> Return(R value) {
1936	return internal::ReturnAction<R>(std::move(value));
1937	}
1938
1939	// Creates an action that returns NULL.
1940	inline PolymorphicAction<internal::ReturnNullAction> ReturnNull() {
1941	return MakePolymorphicAction(impl: internal::ReturnNullAction ());
1942	}
1943
1944	// Creates an action that returns from a void function.
1945	inline PolymorphicAction<internal::ReturnVoidAction> Return() {
1946	return MakePolymorphicAction(impl: internal::ReturnVoidAction ());
1947	}
1948
1949	// Creates an action that returns the reference to a variable.
1950	template <typename R>
1951	inline internal::ReturnRefAction<R> ReturnRef(R& x) { // NOLINT
1952	return internal::ReturnRefAction<R>(x);
1953	}
1954
1955	// Prevent using ReturnRef on reference to temporary.
1956	template <typename R, R* = nullptr>
1957	internal::ReturnRefAction<R> ReturnRef(R&&) = delete;
1958
1959	// Creates an action that returns the reference to a copy of the
1960	// argument. The copy is created when the action is constructed and
1961	// lives as long as the action.
1962	template <typename R>
1963	inline internal::ReturnRefOfCopyAction<R> ReturnRefOfCopy(const R& x) {
1964	return internal::ReturnRefOfCopyAction<R>(x);
1965	}
1966
1967	// DEPRECATED: use Return(x) directly with WillOnce.
1968	//
1969	// Modifies the parent action (a Return() action) to perform a move of the
1970	// argument instead of a copy.
1971	// Return(ByMove()) actions can only be executed once and will assert this
1972	// invariant.
1973	template <typename R>
1974	internal::ByMoveWrapper<R> ByMove(R x) {
1975	return internal::ByMoveWrapper<R>(std::move(x));
1976	}
1977
1978	// Creates an action that returns an element of `vals`. Calling this action will
1979	// repeatedly return the next value from `vals` until it reaches the end and
1980	// will restart from the beginning.
1981	template <typename T>
1982	internal::ReturnRoundRobinAction<T> ReturnRoundRobin(std::vector<T> vals) {
1983	return internal::ReturnRoundRobinAction<T>(std::move(vals));
1984	}
1985
1986	// Creates an action that returns an element of `vals`. Calling this action will
1987	// repeatedly return the next value from `vals` until it reaches the end and
1988	// will restart from the beginning.
1989	template <typename T>
1990	internal::ReturnRoundRobinAction<T> ReturnRoundRobin(
1991	std::initializer_list<T> vals) {
1992	return internal::ReturnRoundRobinAction<T>(std::vector<T>(vals));
1993	}
1994
1995	// Creates an action that does the default action for the give mock function.
1996	inline internal::DoDefaultAction DoDefault() {
1997	return internal::DoDefaultAction ();
1998	}
1999
2000	// Creates an action that sets the variable pointed by the N-th
2001	// (0-based) function argument to 'value'.
2002	template <size_t N, typename T>
2003	internal::SetArgumentPointeeAction<N, T> SetArgPointee(T value) {
2004	return {std::move(value)};
2005	}
2006
2007	// The following version is DEPRECATED.
2008	template <size_t N, typename T>
2009	internal::SetArgumentPointeeAction<N, T> SetArgumentPointee(T value) {
2010	return {std::move(value)};
2011	}
2012
2013	// Creates an action that sets a pointer referent to a given value.
2014	template <typename T1, typename T2>
2015	PolymorphicAction<internal::AssignAction<T1, T2>> Assign(T1* ptr, T2 val) {
2016	return MakePolymorphicAction(internal::AssignAction<T1, T2>(ptr, val));
2017	}
2018
2019	#ifndef GTEST_OS_WINDOWS_MOBILE
2020
2021	// Creates an action that sets errno and returns the appropriate error.
2022	template <typename T>
2023	PolymorphicAction<internal::SetErrnoAndReturnAction<T>> SetErrnoAndReturn(
2024	int errval, T result) {
2025	return MakePolymorphicAction(
2026	internal::SetErrnoAndReturnAction<T>(errval, result));
2027	}
2028
2029	#endif // !GTEST_OS_WINDOWS_MOBILE
2030
2031	// Various overloads for Invoke().
2032
2033	// Legacy function.
2034	// Actions can now be implicitly constructed from callables. No need to create
2035	// wrapper objects.
2036	// This function exists for backwards compatibility.
2037	template <typename FunctionImpl>
2038	typename std::decay<FunctionImpl>::type Invoke(FunctionImpl&& function_impl) {
2039	return std::forward<FunctionImpl>(function_impl);
2040	}
2041
2042	// Creates an action that invokes the given method on the given object
2043	// with the mock function's arguments.
2044	template <class Class, typename MethodPtr>
2045	internal::InvokeMethodAction<Class, MethodPtr> Invoke(Class* obj_ptr,
2046	MethodPtr method_ptr) {
2047	return {obj_ptr, method_ptr};
2048	}
2049
2050	// Creates an action that invokes 'function_impl' with no argument.
2051	template <typename FunctionImpl>
2052	internal::InvokeWithoutArgsAction<typename std::decay<FunctionImpl>::type>
2053	InvokeWithoutArgs(FunctionImpl function_impl) {
2054	return {std::move(function_impl)};
2055	}
2056
2057	// Creates an action that invokes the given method on the given object
2058	// with no argument.
2059	template <class Class, typename MethodPtr>
2060	internal::InvokeMethodWithoutArgsAction<Class, MethodPtr> InvokeWithoutArgs(
2061	Class* obj_ptr, MethodPtr method_ptr) {
2062	return {obj_ptr, method_ptr};
2063	}
2064
2065	// Creates an action that performs an_action and throws away its
2066	// result. In other words, it changes the return type of an_action to
2067	// void. an_action MUST NOT return void, or the code won't compile.
2068	template <typename A>
2069	inline internal::IgnoreResultAction<A> IgnoreResult(const A& an_action) {
2070	return internal::IgnoreResultAction<A>(an_action);
2071	}
2072
2073	// Creates a reference wrapper for the given L-value. If necessary,
2074	// you can explicitly specify the type of the reference. For example,
2075	// suppose 'derived' is an object of type Derived, ByRef(derived)
2076	// would wrap a Derived&. If you want to wrap a const Base& instead,
2077	// where Base is a base class of Derived, just write:
2078	//
2079	// ByRef<const Base>(derived)
2080	//
2081	// N.B. ByRef is redundant with std::ref, std::cref and std::reference_wrapper.
2082	// However, it may still be used for consistency with ByMove().
2083	template <typename T>
2084	inline ::std::reference_wrapper<T> ByRef(T& l_value) { // NOLINT
2085	return ::std::reference_wrapper<T>(l_value);
2086	}
2087
2088	// The ReturnNew<T>(a1, a2, ..., a_k) action returns a pointer to a new
2089	// instance of type T, constructed on the heap with constructor arguments
2090	// a1, a2, ..., and a_k. The caller assumes ownership of the returned value.
2091	template <typename T, typename... Params>
2092	internal::ReturnNewAction<T, typename std::decay<Params>::type...> ReturnNew(
2093	Params&&... params) {
2094	return {std::forward_as_tuple(std::forward<Params>(params)...)};
2095	}
2096
2097	// Action ReturnArg<k>() returns the k-th argument of the mock function.
2098	template <size_t k>
2099	internal::ReturnArgAction<k> ReturnArg() {
2100	return {};
2101	}
2102
2103	// Action SaveArg<k>(pointer) saves the k-th (0-based) argument of the
2104	// mock function to pointer.*
2105	template <size_t k, typename Ptr>
2106	internal::SaveArgAction<k, Ptr> SaveArg(Ptr pointer) {
2107	return {pointer};
2108	}
2109
2110	// Action SaveArgByMove<k>(pointer) moves the k-th (0-based) argument of the
2111	// mock function into pointer.*
2112	template <size_t k, typename Ptr>
2113	internal::SaveArgByMoveAction<k, Ptr> SaveArgByMove(Ptr pointer) {
2114	return {pointer};
2115	}
2116
2117	// Action SaveArgPointee<k>(pointer) saves the value pointed to
2118	// by the k-th (0-based) argument of the mock function to pointer.*
2119	template <size_t k, typename Ptr>
2120	internal::SaveArgPointeeAction<k, Ptr> SaveArgPointee(Ptr pointer) {
2121	return {pointer};
2122	}
2123
2124	// Action SetArgReferee<k>(value) assigns 'value' to the variable
2125	// referenced by the k-th (0-based) argument of the mock function.
2126	template <size_t k, typename T>
2127	internal::SetArgRefereeAction<k, typename std::decay<T>::type> SetArgReferee(
2128	T&& value) {
2129	return {std::forward<T>(value)};
2130	}
2131
2132	// Action SetArrayArgument<k>(first, last) copies the elements in
2133	// source range [first, last) to the array pointed to by the k-th
2134	// (0-based) argument, which can be either a pointer or an
2135	// iterator. The action does not take ownership of the elements in the
2136	// source range.
2137	template <size_t k, typename I1, typename I2>
2138	internal::SetArrayArgumentAction<k, I1, I2> SetArrayArgument(I1 first,
2139	I2 last) {
2140	return {first, last};
2141	}
2142
2143	// Action DeleteArg<k>() deletes the k-th (0-based) argument of the mock
2144	// function.
2145	template <size_t k>
2146	internal::DeleteArgAction<k> DeleteArg() {
2147	return {};
2148	}
2149
2150	// This action returns the value pointed to by 'pointer'.
2151	template <typename Ptr>
2152	internal::ReturnPointeeAction<Ptr> ReturnPointee(Ptr pointer) {
2153	return {pointer};
2154	}
2155
2156	#if GTEST_HAS_EXCEPTIONS
2157	// Action Throw(exception) can be used in a mock function of any type
2158	// to throw the given exception. Any copyable value can be thrown,
2159	// except for std::exception_ptr, which is likely a mistake if
2160	// thrown directly.
2161	template <typename T>
2162	typename std::enable_if<
2163	!std::is_base_of<std::exception_ptr, typename std::decay<T>::type>::value,
2164	internal::ThrowAction<typename std::decay<T>::type>>::type
2165	Throw(T&& exception) {
2166	return {std::forward<T>(exception)};
2167	}
2168	// Action Rethrow(exception_ptr) can be used in a mock function of any type
2169	// to rethrow any exception_ptr. Note that the same object is thrown each time.
2170	inline internal::RethrowAction Rethrow(std::exception_ptr exception) {
2171	return {std::move(exception)};
2172	}
2173	#endif // GTEST_HAS_EXCEPTIONS
2174
2175	namespace internal {
2176
2177	// A macro from the ACTION family (defined later in gmock-generated-actions.h)*
2178	// defines an action that can be used in a mock function. Typically,
2179	// these actions only care about a subset of the arguments of the mock
2180	// function. For example, if such an action only uses the second
2181	// argument, it can be used in any mock function that takes >= 2
2182	// arguments where the type of the second argument is compatible.
2183	//
2184	// Therefore, the action implementation must be prepared to take more
2185	// arguments than it needs. The ExcessiveArg type is used to
2186	// represent those excessive arguments. In order to keep the compiler
2187	// error messages tractable, we define it in the testing namespace
2188	// instead of testing::internal. However, this is an INTERNAL TYPE
2189	// and subject to change without notice, so a user MUST NOT USE THIS
2190	// TYPE DIRECTLY.
2191	struct ExcessiveArg {};
2192
2193	// Builds an implementation of an Action<> for some particular signature, using
2194	// a class defined by an ACTION macro.*
2195	template <typename F, typename Impl>
2196	struct ActionImpl;
2197
2198	template <typename Impl>
2199	struct ImplBase {
2200	struct Holder {
2201	// Allows each copy of the Action<> to get to the Impl.
2202	explicit operator const Impl&() const { return *ptr; }
2203	std::shared_ptr<Impl> ptr;
2204	};
2205	using type = typename std::conditional<std::is_constructible<Impl>::value,
2206	Impl, Holder>::type;
2207	};
2208
2209	template <typename R, typename... Args, typename Impl>
2210	struct ActionImpl<R(Args...), Impl> : ImplBase<Impl>::type {
2211	using Base = typename ImplBase<Impl>::type;
2212	using function_type = R(Args...);
2213	using args_type = std::tuple<Args...>;
2214
2215	ActionImpl() = default; // Only defined if appropriate for Base.
2216	explicit ActionImpl(std::shared_ptr<Impl> impl) : Base{std::move(impl)} {}
2217
2218	R operator()(Args&&... arg) const {
2219	static constexpr size_t kMaxArgs =
2220	sizeof...(Args) <= `10` ? sizeof...(Args) : `10`;
2221	return Apply(std::make_index_sequence<kMaxArgs>{},
2222	std::make_index_sequence<`10` - kMaxArgs>{},
2223	args_type{std::forward<Args>(arg)...});
2224	}
2225
2226	template <std::size_t... arg_id, std::size_t... excess_id>
2227	R Apply(std::index_sequence<arg_id...>, std::index_sequence<excess_id...>,
2228	const args_type& args) const {
2229	// Impl need not be specific to the signature of action being implemented;
2230	// only the implementing function body needs to have all of the specific
2231	// types instantiated. Up to 10 of the args that are provided by the
2232	// args_type get passed, followed by a dummy of unspecified type for the
2233	// remainder up to 10 explicit args.
2234	static constexpr ExcessiveArg kExcessArg{};
2235	return static_cast<const Impl&>(*this)
2236	.template gmock_PerformImpl<
2237	/function_type=/function_type, /return_type=/R,
2238	/args_type=/args_type,
2239	/argN_type=/
2240	typename std::tuple_element<arg_id, args_type>::type...>(
2241	/args=/args, std::get<arg_id>(args)...,
2242	((void)excess_id, kExcessArg)...);
2243	}
2244	};
2245
2246	// Stores a default-constructed Impl as part of the Action<>'s
2247	// std::function<>. The Impl should be trivial to copy.
2248	template <typename F, typename Impl>
2249	::testing::Action<F> MakeAction() {
2250	return ::testing::Action<F>(ActionImpl<F, Impl>());
2251	}
2252
2253	// Stores just the one given instance of Impl.
2254	template <typename F, typename Impl>
2255	::testing::Action<F> MakeAction(std::shared_ptr<Impl> impl) {
2256	return ::testing::Action<F>(ActionImpl<F, Impl>(std::move(impl)));
2257	}
2258
2259	#define GMOCK_INTERNAL_ARG_UNUSED(i, data, el) \
2260	, [[maybe_unused]] const arg##i##_type& arg##i
2261	#define GMOCK_ACTION_ARG_TYPES_AND_NAMES_UNUSED_ \
2262	[[maybe_unused]] const args_type& args GMOCK_PP_REPEAT( \
2263	GMOCK_INTERNAL_ARG_UNUSED, , 10)
2264
2265	#define GMOCK_INTERNAL_ARG(i, data, el) , const arg##i##_type& arg##i
2266	#define GMOCK_ACTION_ARG_TYPES_AND_NAMES_ \
2267	const args_type& args GMOCK_PP_REPEAT(GMOCK_INTERNAL_ARG, , 10)
2268
2269	#define GMOCK_INTERNAL_TEMPLATE_ARG(i, data, el) , typename arg##i##_type
2270	#define GMOCK_ACTION_TEMPLATE_ARGS_NAMES_ \
2271	GMOCK_PP_TAIL(GMOCK_PP_REPEAT(GMOCK_INTERNAL_TEMPLATE_ARG, , 10))
2272
2273	#define GMOCK_INTERNAL_TYPENAME_PARAM(i, data, param) , typename param##_type
2274	#define GMOCK_ACTION_TYPENAME_PARAMS_(params) \
2275	GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_TYPENAME_PARAM, , params))
2276
2277	#define GMOCK_INTERNAL_TYPE_PARAM(i, data, param) , param##_type
2278	#define GMOCK_ACTION_TYPE_PARAMS_(params) \
2279	GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_TYPE_PARAM, , params))
2280
2281	#define GMOCK_INTERNAL_TYPE_GVALUE_PARAM(i, data, param) \
2282	, param##_type gmock_p##i
2283	#define GMOCK_ACTION_TYPE_GVALUE_PARAMS_(params) \
2284	GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_TYPE_GVALUE_PARAM, , params))
2285
2286	#define GMOCK_INTERNAL_GVALUE_PARAM(i, data, param) \
2287	, std::forward<param##_type>(gmock_p##i)
2288	#define GMOCK_ACTION_GVALUE_PARAMS_(params) \
2289	GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_GVALUE_PARAM, , params))
2290
2291	#define GMOCK_INTERNAL_INIT_PARAM(i, data, param) \
2292	, param(::std::forward<param##_type>(gmock_p##i))
2293	#define GMOCK_ACTION_INIT_PARAMS_(params) \
2294	GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_INIT_PARAM, , params))
2295
2296	#define GMOCK_INTERNAL_FIELD_PARAM(i, data, param) param##_type param;
2297	#define GMOCK_ACTION_FIELD_PARAMS_(params) \
2298	GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_FIELD_PARAM, , params)
2299
2300	#define GMOCK_INTERNAL_ACTION(name, full_name, params) \
2301	template <GMOCK_ACTION_TYPENAME_PARAMS_(params)> \
2302	class full_name { \
2303	public: \
2304	explicit full_name(GMOCK_ACTION_TYPE_GVALUE_PARAMS_(params)) \
2305	: impl_(std::make_shared<gmock_Impl>( \
2306	GMOCK_ACTION_GVALUE_PARAMS_(params))) {} \
2307	full_name(const full_name&) = default; \
2308	full_name(full_name&&) noexcept = default; \
2309	template <typename F> \
2310	operator ::testing::Action<F>() const { \
2311	return ::testing::internal::MakeAction<F>(impl_); \
2312	} \
2313	\
2314	private: \
2315	class gmock_Impl { \
2316	public: \
2317	explicit gmock_Impl(GMOCK_ACTION_TYPE_GVALUE_PARAMS_(params)) \
2318	: GMOCK_ACTION_INIT_PARAMS_(params) {} \
2319	template <typename function_type, typename return_type, \
2320	typename args_type, GMOCK_ACTION_TEMPLATE_ARGS_NAMES_> \
2321	return_type gmock_PerformImpl(GMOCK_ACTION_ARG_TYPES_AND_NAMES_) const; \
2322	GMOCK_ACTION_FIELD_PARAMS_(params) \
2323	}; \
2324	std::shared_ptr<const gmock_Impl> impl_; \
2325	}; \
2326	template <GMOCK_ACTION_TYPENAME_PARAMS_(params)> \
2327	[[nodiscard]] inline full_name<GMOCK_ACTION_TYPE_PARAMS_(params)> name( \
2328	GMOCK_ACTION_TYPE_GVALUE_PARAMS_(params)); \
2329	template <GMOCK_ACTION_TYPENAME_PARAMS_(params)> \
2330	inline full_name<GMOCK_ACTION_TYPE_PARAMS_(params)> name( \
2331	GMOCK_ACTION_TYPE_GVALUE_PARAMS_(params)) { \
2332	return full_name<GMOCK_ACTION_TYPE_PARAMS_(params)>( \
2333	GMOCK_ACTION_GVALUE_PARAMS_(params)); \
2334	} \
2335	template <GMOCK_ACTION_TYPENAME_PARAMS_(params)> \
2336	template <typename function_type, typename return_type, typename args_type, \
2337	GMOCK_ACTION_TEMPLATE_ARGS_NAMES_> \
2338	return_type \
2339	full_name<GMOCK_ACTION_TYPE_PARAMS_(params)>::gmock_Impl::gmock_PerformImpl( \
2340	GMOCK_ACTION_ARG_TYPES_AND_NAMES_UNUSED_) const
2341
2342	} // namespace internal
2343
2344	// Similar to GMOCK_INTERNAL_ACTION, but no bound parameters are stored.
2345	#define ACTION(name) \
2346	class name##Action { \
2347	public: \
2348	explicit name##Action() noexcept {} \
2349	name##Action(const name##Action&) noexcept {} \
2350	template <typename F> \
2351	operator ::testing::Action<F>() const { \
2352	return ::testing::internal::MakeAction<F, gmock_Impl>(); \
2353	} \
2354	\
2355	private: \
2356	class gmock_Impl { \
2357	public: \
2358	template <typename function_type, typename return_type, \
2359	typename args_type, GMOCK_ACTION_TEMPLATE_ARGS_NAMES_> \
2360	return_type gmock_PerformImpl(GMOCK_ACTION_ARG_TYPES_AND_NAMES_) const; \
2361	}; \
2362	}; \
2363	[[nodiscard]] inline name##Action name(); \
2364	inline name##Action name() { return name##Action(); } \
2365	template <typename function_type, typename return_type, typename args_type, \
2366	GMOCK_ACTION_TEMPLATE_ARGS_NAMES_> \
2367	return_type name##Action::gmock_Impl::gmock_PerformImpl( \
2368	GMOCK_ACTION_ARG_TYPES_AND_NAMES_UNUSED_) const
2369
2370	#define ACTION_P(name, ...) \
2371	GMOCK_INTERNAL_ACTION(name, name##ActionP, (__VA_ARGS__))
2372
2373	#define ACTION_P2(name, ...) \
2374	GMOCK_INTERNAL_ACTION(name, name##ActionP2, (__VA_ARGS__))
2375
2376	#define ACTION_P3(name, ...) \
2377	GMOCK_INTERNAL_ACTION(name, name##ActionP3, (__VA_ARGS__))
2378
2379	#define ACTION_P4(name, ...) \
2380	GMOCK_INTERNAL_ACTION(name, name##ActionP4, (__VA_ARGS__))
2381
2382	#define ACTION_P5(name, ...) \
2383	GMOCK_INTERNAL_ACTION(name, name##ActionP5, (__VA_ARGS__))
2384
2385	#define ACTION_P6(name, ...) \
2386	GMOCK_INTERNAL_ACTION(name, name##ActionP6, (__VA_ARGS__))
2387
2388	#define ACTION_P7(name, ...) \
2389	GMOCK_INTERNAL_ACTION(name, name##ActionP7, (__VA_ARGS__))
2390
2391	#define ACTION_P8(name, ...) \
2392	GMOCK_INTERNAL_ACTION(name, name##ActionP8, (__VA_ARGS__))
2393
2394	#define ACTION_P9(name, ...) \
2395	GMOCK_INTERNAL_ACTION(name, name##ActionP9, (__VA_ARGS__))
2396
2397	#define ACTION_P10(name, ...) \
2398	GMOCK_INTERNAL_ACTION(name, name##ActionP10, (__VA_ARGS__))
2399
2400	} // namespace testing
2401
2402	GTEST_DISABLE_MSC_WARNINGS_POP_() // 4100
2403
2404	#endif // GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_ACTIONS_H_
2405

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