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

1	// Copyright 2007, Google Inc.
2	// All rights reserved.
3	//
4	// Redistribution and use in source and binary forms, with or without
5	// modification, are permitted provided that the following conditions are
6	// met:
7	//
8	// Redistributions of source code must retain the above copyright*
9	// notice, this list of conditions and the following disclaimer.
10	// Redistributions in binary form must reproduce the above*
11	// copyright notice, this list of conditions and the following disclaimer
12	// in the documentation and/or other materials provided with the
13	// distribution.
14	// Neither the name of Google Inc. nor the names of its*
15	// contributors may be used to endorse or promote products derived from
16	// this software without specific prior written permission.
17	//
18	// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19	// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20	// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21	// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22	// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23	// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24	// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25	// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26	// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27	// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28	// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 <functional>
139	#include <memory>
140	#include <string>
141	#include <tuple>
142	#include <type_traits>
143	#include <utility>
144
145	#include "gmock/internal/gmock-internal-utils.h"
146	#include "gmock/internal/gmock-port.h"
147	#include "gmock/internal/gmock-pp.h"
148
149	GTEST_DISABLE_MSC_WARNINGS_PUSH_(`4100`)
150
151	namespace testing {
152
153	// To implement an action Foo, define:
154	// 1. a class FooAction that implements the ActionInterface interface, and
155	// 2. a factory function that creates an Action object from a
156	// const FooAction.*
157	//
158	// The two-level delegation design follows that of Matcher, providing
159	// consistency for extension developers. It also eases ownership
160	// management as Action objects can now be copied like plain values.
161
162	namespace internal {
163
164	// BuiltInDefaultValueGetter<T, true>::Get() returns a
165	// default-constructed T value. BuiltInDefaultValueGetter<T,
166	// false>::Get() crashes with an error.
167	//
168	// This primary template is used when kDefaultConstructible is true.
169	template <typename T, bool kDefaultConstructible>
170	struct BuiltInDefaultValueGetter {
171	static T Get() { return T(); }
172	};
173	template <typename T>
174	struct BuiltInDefaultValueGetter<T, false> {
175	static T Get() {
176	Assert(condition: false, __FILE__, __LINE__,
177	msg: "Default action undefined for the function return type.");
178	return internal::Invalid<T>();
179	// The above statement will never be reached, but is required in
180	// order for this function to compile.
181	}
182	};
183
184	// BuiltInDefaultValue<T>::Get() returns the "built-in" default value
185	// for type T, which is NULL when T is a raw pointer type, 0 when T is
186	// a numeric type, false when T is bool, or "" when T is string or
187	// std::string. In addition, in C++11 and above, it turns a
188	// default-constructed T value if T is default constructible. For any
189	// other type T, the built-in default T value is undefined, and the
190	// function will abort the process.
191	template <typename T>
192	class BuiltInDefaultValue {
193	public:
194	// This function returns true if and only if type T has a built-in default
195	// value.
196	static bool Exists() { return ::std::is_default_constructible<T>::value; }
197
198	static T Get() {
199	return BuiltInDefaultValueGetter<
200	T, ::std::is_default_constructible<T>::value>::Get();
201	}
202	};
203
204	// This partial specialization says that we use the same built-in
205	// default value for T and const T.
206	template <typename T>
207	class BuiltInDefaultValue<const T> {
208	public:
209	static bool Exists() { return BuiltInDefaultValue<T>::Exists(); }
210	static T Get() { return BuiltInDefaultValue<T>::Get(); }
211	};
212
213	// This partial specialization defines the default values for pointer
214	// types.
215	template <typename T>
216	class BuiltInDefaultValue<T*> {
217	public:
218	static bool Exists() { return true; }
219	static T* Get() { return nullptr; }
220	};
221
222	// The following specializations define the default values for
223	// specific types we care about.
224	#define GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(type, value) \
225	template <> \
226	class BuiltInDefaultValue<type> { \
227	public: \
228	static bool Exists() { return true; } \
229	static type Get() { return value; } \
230	}
231
232	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(void, ); // NOLINT
233	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(::std::string, "");
234	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(bool, false);
235	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned char, `'\0'`);
236	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed char, `'\0'`);
237	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(char, `'\0'`);
238
239	// There's no need for a default action for signed wchar_t, as that
240	// type is the same as wchar_t for gcc, and invalid for MSVC.
241	//
242	// There's also no need for a default action for unsigned wchar_t, as
243	// that type is the same as unsigned int for gcc, and invalid for
244	// MSVC.
245	#if GMOCK_WCHAR_T_IS_NATIVE_
246	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(wchar_t, `0U`); // NOLINT
247	#endif
248
249	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned short, `0U`); // NOLINT
250	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed short, `0`); // NOLINT
251	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned int, `0U`);
252	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed int, `0`);
253	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned long, `0UL`); // NOLINT
254	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed long, `0L`); // NOLINT
255	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned long long, `0`); // NOLINT
256	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed long long, `0`); // NOLINT
257	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(float, `0`);
258	GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(double, `0`);
259
260	#undef GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_
261
262	// Partial implementations of metaprogramming types from the standard library
263	// not available in C++11.
264
265	template <typename P>
266	struct negation
267	// NOLINTNEXTLINE
268	: std::integral_constant<bool, bool(!P::value)> {};
269
270	// Base case: with zero predicates the answer is always true.
271	template <typename...>
272	struct conjunction : std::true_type {};
273
274	// With a single predicate, the answer is that predicate.
275	template <typename P1>
276	struct conjunction<P1> : P1 {};
277
278	// With multiple predicates the answer is the first predicate if that is false,
279	// and we recurse otherwise.
280	template <typename P1, typename... Ps>
281	struct conjunction<P1, Ps...>
282	: std::conditional<bool(P1::value), conjunction<Ps...>, P1>::type {};
283
284	template <typename...>
285	struct disjunction : std::false_type {};
286
287	template <typename P1>
288	struct disjunction<P1> : P1 {};
289
290	template <typename P1, typename... Ps>
291	struct disjunction<P1, Ps...>
292	// NOLINTNEXTLINE
293	: std::conditional<!bool(P1::value), disjunction<Ps...>, P1>::type {};
294
295	template <typename...>
296	using void_t = void;
297
298	// Detects whether an expression of type `From` can be implicitly converted to
299	// `To` according to [conv]. In C++17, [conv]/3 defines this as follows:
300	//
301	// An expression e can be implicitly converted to a type T if and only if
302	// the declaration T t=e; is well-formed, for some invented temporary
303	// variable t ([dcl.init]).
304	//
305	// [conv]/2 implies we can use function argument passing to detect whether this
306	// initialization is valid.
307	//
308	// Note that this is distinct from is_convertible, which requires this be valid:
309	//
310	// To test() {
311	// return declval<From>();
312	// }
313	//
314	// In particular, is_convertible doesn't give the correct answer when `To` and
315	// `From` are the same non-moveable type since `declval<From>` will be an rvalue
316	// reference, defeating the guaranteed copy elision that would otherwise make
317	// this function work.
318	//
319	// REQUIRES: `From` is not cv void.
320	template <typename From, typename To>
321	struct is_implicitly_convertible {
322	private:
323	// A function that accepts a parameter of type T. This can be called with type
324	// U successfully only if U is implicitly convertible to T.
325	template <typename T>
326	static void Accept(T);
327
328	// A function that creates a value of type T.
329	template <typename T>
330	static T Make();
331
332	// An overload be selected when implicit conversion from T to To is possible.
333	template <typename T, typename = decltype(Accept<To>(Make<T>()))>
334	static std::true_type TestImplicitConversion(int);
335
336	// A fallback overload selected in all other cases.
337	template <typename T>
338	static std::false_type TestImplicitConversion(...);
339
340	public:
341	using type = decltype(TestImplicitConversion<From>(`0`));
342	static constexpr bool value = type::value;
343	};
344
345	// Like std::invoke_result_t from C++17, but works only for objects with call
346	// operators (not e.g. member function pointers, which we don't need specific
347	// support for in OnceAction because std::function deals with them).
348	template <typename F, typename... Args>
349	using call_result_t = decltype(std::declval<F>()(std::declval<Args>()...));
350
351	template <typename Void, typename R, typename F, typename... Args>
352	struct is_callable_r_impl : std::false_type {};
353
354	// Specialize the struct for those template arguments where call_result_t is
355	// well-formed. When it's not, the generic template above is chosen, resulting
356	// in std::false_type.
357	template <typename R, typename F, typename... Args>
358	struct is_callable_r_impl<void_t<call_result_t<F, Args...>>, R, F, Args...>
359	: std::conditional<
360	std::is_void<R>::value, //
361	std::true_type, //
362	is_implicitly_convertible<call_result_t<F, Args...>, R>>::type {};
363
364	// Like std::is_invocable_r from C++17, but works only for objects with call
365	// operators. See the note on call_result_t.
366	template <typename R, typename F, typename... Args>
367	using is_callable_r = is_callable_r_impl<void, R, F, Args...>;
368
369	// Like std::as_const from C++17.
370	template <typename T>
371	typename std::add_const<T>::type& as_const(T& t) {
372	return t;
373	}
374
375	} // namespace internal
376
377	// Specialized for function types below.
378	template <typename F>
379	class OnceAction;
380
381	// An action that can only be used once.
382	//
383	// This is accepted by WillOnce, which doesn't require the underlying action to
384	// be copy-constructible (only move-constructible), and promises to invoke it as
385	// an rvalue reference. This allows the action to work with move-only types like
386	// std::move_only_function in a type-safe manner.
387	//
388	// For example:
389	//
390	// // Assume we have some API that needs to accept a unique pointer to some
391	// // non-copyable object Foo.
392	// void AcceptUniquePointer(std::unique_ptr<Foo> foo);
393	//
394	// // We can define an action that provides a Foo to that API. Because It
395	// // has to give away its unique pointer, it must not be called more than
396	// // once, so its call operator is &&-qualified.
397	// struct ProvideFoo {
398	// std::unique_ptr<Foo> foo;
399	//
400	// void operator()() && {
401	// AcceptUniquePointer(std::move(Foo));
402	// }
403	// };
404	//
405	// // This action can be used with WillOnce.
406	// EXPECT_CALL(mock, Call)
407	// .WillOnce(ProvideFoo{std::make_unique<Foo>(...)});
408	//
409	// // But a call to WillRepeatedly will fail to compile. This is correct,
410	// // since the action cannot correctly be used repeatedly.
411	// EXPECT_CALL(mock, Call)
412	// .WillRepeatedly(ProvideFoo{std::make_unique<Foo>(...)});
413	//
414	// A less-contrived example would be an action that returns an arbitrary type,
415	// whose &&-qualified call operator is capable of dealing with move-only types.
416	template <typename Result, typename... Args>
417	class OnceAction<Result(Args...)> final {
418	private:
419	// True iff we can use the given callable type (or lvalue reference) directly
420	// via StdFunctionAdaptor.
421	template <typename Callable>
422	using IsDirectlyCompatible = internal::conjunction<
423	// It must be possible to capture the callable in StdFunctionAdaptor.
424	std::is_constructible<typename std::decay<Callable>::type, Callable>,
425	// The callable must be compatible with our signature.
426	internal::is_callable_r<Result, typename std::decay<Callable>::type,
427	Args...>>;
428
429	// True iff we can use the given callable type via StdFunctionAdaptor once we
430	// ignore incoming arguments.
431	template <typename Callable>
432	using IsCompatibleAfterIgnoringArguments = internal::conjunction<
433	// It must be possible to capture the callable in a lambda.
434	std::is_constructible<typename std::decay<Callable>::type, Callable>,
435	// The callable must be invocable with zero arguments, returning something
436	// convertible to Result.
437	internal::is_callable_r<Result, typename std::decay<Callable>::type>>;
438
439	public:
440	// Construct from a callable that is directly compatible with our mocked
441	// signature: it accepts our function type's arguments and returns something
442	// convertible to our result type.
443	template <typename Callable,
444	typename std::enable_if<
445	internal::conjunction<
446	// Teach clang on macOS that we're not talking about a
447	// copy/move constructor here. Otherwise it gets confused
448	// when checking the is_constructible requirement of our
449	// traits above.
450	internal::negation<std::is_same<
451	OnceAction, typename std::decay<Callable>::type>>,
452	IsDirectlyCompatible<Callable>> //
453	::value,
454	int>::type = `0`>
455	OnceAction(Callable&& callable) // NOLINT
456	: function_(StdFunctionAdaptor<typename std::decay<Callable>::type>(
457	{}, std::forward<Callable>(callable))) {}
458
459	// As above, but for a callable that ignores the mocked function's arguments.
460	template <typename Callable,
461	typename std::enable_if<
462	internal::conjunction<
463	// Teach clang on macOS that we're not talking about a
464	// copy/move constructor here. Otherwise it gets confused
465	// when checking the is_constructible requirement of our
466	// traits above.
467	internal::negation<std::is_same<
468	OnceAction, typename std::decay<Callable>::type>>,
469	// Exclude callables for which the overload above works.
470	// We'd rather provide the arguments if possible.
471	internal::negation<IsDirectlyCompatible<Callable>>,
472	IsCompatibleAfterIgnoringArguments<Callable>>::value,
473	int>::type = `0`>
474	OnceAction(Callable&& callable) // NOLINT
475	// Call the constructor above with a callable
476	// that ignores the input arguments.
477	: OnceAction(IgnoreIncomingArguments<typename std::decay<Callable>::type>{
478	std::forward<Callable>(callable)}) {}
479
480	// We are naturally copyable because we store only an std::function, but
481	// semantically we should not be copyable.
482	OnceAction(const OnceAction&) = delete;
483	OnceAction& operator=(const OnceAction&) = delete;
484	OnceAction(OnceAction&&) = default;
485
486	// Invoke the underlying action callable with which we were constructed,
487	// handing it the supplied arguments.
488	Result Call(Args... args) && {
489	return function_(std::forward<Args>(args)...);
490	}
491
492	private:
493	// An adaptor that wraps a callable that is compatible with our signature and
494	// being invoked as an rvalue reference so that it can be used as an
495	// StdFunctionAdaptor. This throws away type safety, but that's fine because
496	// this is only used by WillOnce, which we know calls at most once.
497	//
498	// Once we have something like std::move_only_function from C++23, we can do
499	// away with this.
500	template <typename Callable>
501	class StdFunctionAdaptor final {
502	public:
503	// A tag indicating that the (otherwise universal) constructor is accepting
504	// the callable itself, instead of e.g. stealing calls for the move
505	// constructor.
506	struct CallableTag final {};
507
508	template <typename F>
509	explicit StdFunctionAdaptor(CallableTag, F&& callable)
510	: callable_(std::make_shared<Callable>(std::forward<F>(callable))) {}
511
512	// Rather than explicitly returning Result, we return whatever the wrapped
513	// callable returns. This allows for compatibility with existing uses like
514	// the following, when the mocked function returns void:
515	//
516	// EXPECT_CALL(mock_fn_, Call)
517	// .WillOnce([&] {
518	// [...]
519	// return 0;
520	// });
521	//
522	// Such a callable can be turned into std::function<void()>. If we use an
523	// explicit return type of Result here then it doesn't* work with*
524	// std::function, because we'll get a "void function should not return a
525	// value" error.
526	//
527	// We need not worry about incompatible result types because the SFINAE on
528	// OnceAction already checks this for us. std::is_invocable_r_v itself makes
529	// the same allowance for void result types.
530	template <typename... ArgRefs>
531	internal::call_result_t<Callable, ArgRefs...> operator()(
532	ArgRefs&&... args) const {
533	return std::move(*callable_)(std::forward<ArgRefs>(args)...);
534	}
535
536	private:
537	// We must put the callable on the heap so that we are copyable, which
538	// std::function needs.
539	std::shared_ptr<Callable> callable_;
540	};
541
542	// An adaptor that makes a callable that accepts zero arguments callable with
543	// our mocked arguments.
544	template <typename Callable>
545	struct IgnoreIncomingArguments {
546	internal::call_result_t<Callable> operator()(Args&&...) {
547	return std::move(callable)();
548	}
549
550	Callable callable;
551	};
552
553	std::function<Result(Args...)> function_;
554	};
555
556	// When an unexpected function call is encountered, Google Mock will
557	// let it return a default value if the user has specified one for its
558	// return type, or if the return type has a built-in default value;
559	// otherwise Google Mock won't know what value to return and will have
560	// to abort the process.
561	//
562	// The DefaultValue<T> class allows a user to specify the
563	// default value for a type T that is both copyable and publicly
564	// destructible (i.e. anything that can be used as a function return
565	// type). The usage is:
566	//
567	// // Sets the default value for type T to be foo.
568	// DefaultValue<T>::Set(foo);
569	template <typename T>
570	class DefaultValue {
571	public:
572	// Sets the default value for type T; requires T to be
573	// copy-constructable and have a public destructor.
574	static void Set(T x) {
575	delete producer_;
576	producer_ = new FixedValueProducer(x);
577	}
578
579	// Provides a factory function to be called to generate the default value.
580	// This method can be used even if T is only move-constructible, but it is not
581	// limited to that case.
582	typedef T (*FactoryFunction)();
583	static void SetFactory(FactoryFunction factory) {
584	delete producer_;
585	producer_ = new FactoryValueProducer(factory);
586	}
587
588	// Unsets the default value for type T.
589	static void Clear() {
590	delete producer_;
591	producer_ = nullptr;
592	}
593
594	// Returns true if and only if the user has set the default value for type T.
595	static bool IsSet() { return producer_ != nullptr; }
596
597	// Returns true if T has a default return value set by the user or there
598	// exists a built-in default value.
599	static bool Exists() {
600	return IsSet() \|\| internal::BuiltInDefaultValue<T>::Exists();
601	}
602
603	// Returns the default value for type T if the user has set one;
604	// otherwise returns the built-in default value. Requires that Exists()
605	// is true, which ensures that the return value is well-defined.
606	static T Get() {
607	return producer_ == nullptr ? internal::BuiltInDefaultValue<T>::Get()
608	: producer_->Produce();
609	}
610
611	private:
612	class ValueProducer {
613	public:
614	virtual ~ValueProducer() = default;
615	virtual T Produce() = `0`;
616	};
617
618	class FixedValueProducer : public ValueProducer {
619	public:
620	explicit FixedValueProducer(T value) : value_(value) {}
621	T Produce() override { return value_; }
622
623	private:
624	const T value_;
625	FixedValueProducer(const FixedValueProducer&) = delete;
626	FixedValueProducer& operator=(const FixedValueProducer&) = delete;
627	};
628
629	class FactoryValueProducer : public ValueProducer {
630	public:
631	explicit FactoryValueProducer(FactoryFunction factory)
632	: factory_(factory) {}
633	T Produce() override { return factory_(); }
634
635	private:
636	const FactoryFunction factory_;
637	FactoryValueProducer(const FactoryValueProducer&) = delete;
638	FactoryValueProducer& operator=(const FactoryValueProducer&) = delete;
639	};
640
641	static ValueProducer* producer_;
642	};
643
644	// This partial specialization allows a user to set default values for
645	// reference types.
646	template <typename T>
647	class DefaultValue<T&> {
648	public:
649	// Sets the default value for type T&.
650	static void Set(T& x) { // NOLINT
651	address_ = &x;
652	}
653
654	// Unsets the default value for type T&.
655	static void Clear() { address_ = nullptr; }
656
657	// Returns true if and only if the user has set the default value for type T&.
658	static bool IsSet() { return address_ != nullptr; }
659
660	// Returns true if T has a default return value set by the user or there
661	// exists a built-in default value.
662	static bool Exists() {
663	return IsSet() \|\| internal::BuiltInDefaultValue<T&>::Exists();
664	}
665
666	// Returns the default value for type T& if the user has set one;
667	// otherwise returns the built-in default value if there is one;
668	// otherwise aborts the process.
669	static T& Get() {
670	return address_ == nullptr ? internal::BuiltInDefaultValue<T&>::Get()
671	: *address_;
672	}
673
674	private:
675	static T* address_;
676	};
677
678	// This specialization allows DefaultValue<void>::Get() to
679	// compile.
680	template <>
681	class DefaultValue<void> {
682	public:
683	static bool Exists() { return true; }
684	static void Get() {}
685	};
686
687	// Points to the user-set default value for type T.
688	template <typename T>
689	typename DefaultValue<T>::ValueProducer* DefaultValue<T>::producer_ = nullptr;
690
691	// Points to the user-set default value for type T&.
692	template <typename T>
693	T* DefaultValue<T&>::address_ = nullptr;
694
695	// Implement this interface to define an action for function type F.
696	template <typename F>
697	class ActionInterface {
698	public:
699	typedef typename internal::Function<F>::Result Result;
700	typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
701
702	ActionInterface() = default;
703	virtual ~ActionInterface() = default;
704
705	// Performs the action. This method is not const, as in general an
706	// action can have side effects and be stateful. For example, a
707	// get-the-next-element-from-the-collection action will need to
708	// remember the current element.
709	virtual Result Perform(const ArgumentTuple& args) = `0`;
710
711	private:
712	ActionInterface(const ActionInterface&) = delete;
713	ActionInterface& operator=(const ActionInterface&) = delete;
714	};
715
716	template <typename F>
717	class Action;
718
719	// An Action<R(Args...)> is a copyable and IMMUTABLE (except by assignment)
720	// object that represents an action to be taken when a mock function of type
721	// R(Args...) is called. The implementation of Action<T> is just a
722	// std::shared_ptr to const ActionInterface<T>. Don't inherit from Action! You
723	// can view an object implementing ActionInterface<F> as a concrete action
724	// (including its current state), and an Action<F> object as a handle to it.
725	template <typename R, typename... Args>
726	class Action<R(Args...)> {
727	private:
728	using F = R(Args...);
729
730	// Adapter class to allow constructing Action from a legacy ActionInterface.
731	// New code should create Actions from functors instead.
732	struct ActionAdapter {
733	// Adapter must be copyable to satisfy std::function requirements.
734	::std::shared_ptr<ActionInterface<F>> impl_;
735
736	template <typename... InArgs>
737	typename internal::Function<F>::Result operator()(InArgs&&... args) {
738	return impl_->Perform(
739	::std::forward_as_tuple(::std::forward<InArgs>(args)...));
740	}
741	};
742
743	template <typename G>
744	using IsCompatibleFunctor = std::is_constructible<std::function<F>, G>;
745
746	public:
747	typedef typename internal::Function<F>::Result Result;
748	typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
749
750	// Constructs a null Action. Needed for storing Action objects in
751	// STL containers.
752	Action() = default;
753
754	// Construct an Action from a specified callable.
755	// This cannot take std::function directly, because then Action would not be
756	// directly constructible from lambda (it would require two conversions).
757	template <
758	typename G,
759	typename = typename std::enable_if<internal::disjunction<
760	IsCompatibleFunctor<G>, std::is_constructible<std::function<Result()>,
761	G>>::value>::type>
762	Action(G&& fun) { // NOLINT
763	Init(::std::forward<G>(fun), IsCompatibleFunctor<G>());
764	}
765
766	// Constructs an Action from its implementation.
767	explicit Action(ActionInterface<F>* impl)
768	: fun_(ActionAdapter{::std::shared_ptr<ActionInterface<F>>(impl)}) {}
769
770	// This constructor allows us to turn an Action<Func> object into an
771	// Action<F>, as long as F's arguments can be implicitly converted
772	// to Func's and Func's return type can be implicitly converted to F's.
773	template <typename Func>
774	Action(const Action<Func>& action) // NOLINT
775	: fun_(action.fun_) {}
776
777	// Returns true if and only if this is the DoDefault() action.
778	bool IsDoDefault() const { return fun_ == nullptr; }
779
780	// Performs the action. Note that this method is const even though
781	// the corresponding method in ActionInterface is not. The reason
782	// is that a const Action<F> means that it cannot be re-bound to
783	// another concrete action, not that the concrete action it binds to
784	// cannot change state. (Think of the difference between a const
785	// pointer and a pointer to const.)
786	Result Perform(ArgumentTuple args) const {
787	if (IsDoDefault()) {
788	internal::IllegalDoDefault(__FILE__, __LINE__);
789	}
790	return internal::Apply(fun_, ::std::move(args));
791	}
792
793	// An action can be used as a OnceAction, since it's obviously safe to call it
794	// once.
795	operator OnceAction<F>() const { // NOLINT
796	// Return a OnceAction-compatible callable that calls Perform with the
797	// arguments it is provided. We could instead just return fun_, but then
798	// we'd need to handle the IsDoDefault() case separately.
799	struct OA {
800	Action<F> action;
801
802	R operator()(Args... args) && {
803	return action.Perform(
804	std::forward_as_tuple(std::forward<Args>(args)...));
805	}
806	};
807
808	return OA{*this};
809	}
810
811	private:
812	template <typename G>
813	friend class Action;
814
815	template <typename G>
816	void Init(G&& g, ::std::true_type) {
817	fun_ = ::std::forward<G>(g);
818	}
819
820	template <typename G>
821	void Init(G&& g, ::std::false_type) {
822	fun_ = IgnoreArgs<typename ::std::decay<G>::type>{::std::forward<G>(g)};
823	}
824
825	template <typename FunctionImpl>
826	struct IgnoreArgs {
827	template <typename... InArgs>
828	Result operator()(const InArgs&...) const {
829	return function_impl();
830	}
831
832	FunctionImpl function_impl;
833	};
834
835	// fun_ is an empty function if and only if this is the DoDefault() action.
836	::std::function<F> fun_;
837	};
838
839	// The PolymorphicAction class template makes it easy to implement a
840	// polymorphic action (i.e. an action that can be used in mock
841	// functions of than one type, e.g. Return()).
842	//
843	// To define a polymorphic action, a user first provides a COPYABLE
844	// implementation class that has a Perform() method template:
845	//
846	// class FooAction {
847	// public:
848	// template <typename Result, typename ArgumentTuple>
849	// Result Perform(const ArgumentTuple& args) const {
850	// // Processes the arguments and returns a result, using
851	// // std::get<N>(args) to get the N-th (0-based) argument in the tuple.
852	// }
853	// ...
854	// };
855	//
856	// Then the user creates the polymorphic action using
857	// MakePolymorphicAction(object) where object has type FooAction. See
858	// the definition of Return(void) and SetArgumentPointee<N>(value) for
859	// complete examples.
860	template <typename Impl>
861	class PolymorphicAction {
862	public:
863	explicit PolymorphicAction(const Impl& impl) : impl_(impl) {}
864
865	template <typename F>
866	operator Action<F>() const {
867	return Action<F>(new MonomorphicImpl<F>(impl_));
868	}
869
870	private:
871	template <typename F>
872	class MonomorphicImpl : public ActionInterface<F> {
873	public:
874	typedef typename internal::Function<F>::Result Result;
875	typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
876
877	explicit MonomorphicImpl(const Impl& impl) : impl_(impl) {}
878
879	Result Perform(const ArgumentTuple& args) override {
880	return impl_.template Perform<Result>(args);
881	}
882
883	private:
884	Impl impl_;
885	};
886
887	Impl impl_;
888	};
889
890	// Creates an Action from its implementation and returns it. The
891	// created Action object owns the implementation.
892	template <typename F>
893	Action<F> MakeAction(ActionInterface<F>* impl) {
894	return Action<F>(impl);
895	}
896
897	// Creates a polymorphic action from its implementation. This is
898	// easier to use than the PolymorphicAction<Impl> constructor as it
899	// doesn't require you to explicitly write the template argument, e.g.
900	//
901	// MakePolymorphicAction(foo);
902	// vs
903	// PolymorphicAction<TypeOfFoo>(foo);
904	template <typename Impl>
905	inline PolymorphicAction<Impl> MakePolymorphicAction(const Impl& impl) {
906	return PolymorphicAction<Impl>(impl);
907	}
908
909	namespace internal {
910
911	// Helper struct to specialize ReturnAction to execute a move instead of a copy
912	// on return. Useful for move-only types, but could be used on any type.
913	template <typename T>
914	struct ByMoveWrapper {
915	explicit ByMoveWrapper(T value) : payload(std::move(value)) {}
916	T payload;
917	};
918
919	// The general implementation of Return(R). Specializations follow below.
920	template <typename R>
921	class ReturnAction final {
922	public:
923	explicit ReturnAction(R value) : value_(std::move(value)) {}
924
925	template <typename U, typename... Args,
926	typename = typename std::enable_if<conjunction<
927	// See the requirements documented on Return.
928	negation<std::is_same<void, U>>, //
929	negation<std::is_reference<U>>, //
930	std::is_convertible<R, U>, //
931	std::is_move_constructible<U>>::value>::type>
932	operator OnceAction<U(Args...)>() && { // NOLINT
933	return Impl<U>(std::move(value_));
934	}
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<const R&, U>, //
942	std::is_copy_constructible<U>>::value>::type>
943	operator Action<U(Args...)>() const { // NOLINT
944	return Impl<U>(value_);
945	}
946
947	private:
948	// Implements the Return(x) action for a mock function that returns type U.
949	template <typename U>
950	class Impl final {
951	public:
952	// The constructor used when the return value is allowed to move from the
953	// input value (i.e. we are converting to OnceAction).
954	explicit Impl(R&& input_value)
955	: state_(new State(std::move(input_value))) {}
956
957	// The constructor used when the return value is not allowed to move from
958	// the input value (i.e. we are converting to Action).
959	explicit Impl(const R& input_value) : state_(new State(input_value)) {}
960
961	U operator()() && { return std::move(state_->value); }
962	U operator()() const& { return state_->value; }
963
964	private:
965	// We put our state on the heap so that the compiler-generated copy/move
966	// constructors work correctly even when U is a reference-like type. This is
967	// necessary only because we eagerly create State::value (see the note on
968	// that symbol for details). If we instead had only the input value as a
969	// member then the default constructors would work fine.
970	//
971	// For example, when R is std::string and U is std::string_view, value is a
972	// reference to the string backed by input_value. The copy constructor would
973	// copy both, so that we wind up with a new input_value object (with the
974	// same contents) and a reference to the old* input_value object rather*
975	// than the new one.
976	struct State {
977	explicit State(const R& input_value_in)
978	: input_value(input_value_in),
979	// Make an implicit conversion to Result before initializing the U
980	// object we store, avoiding calling any explicit constructor of U
981	// from R.
982	//
983	// This simulates the language rules: a function with return type U
984	// that does `return R()` requires R to be implicitly convertible to
985	// U, and uses that path for the conversion, even U Result has an
986	// explicit constructor from R.
987	value(ImplicitCast_<U>(internal::as_const(input_value))) {}
988
989	// As above, but for the case where we're moving from the ReturnAction
990	// object because it's being used as a OnceAction.
991	explicit State(R&& input_value_in)
992	: input_value(std::move(input_value_in)),
993	// For the same reason as above we make an implicit conversion to U
994	// before initializing the value.
995	//
996	// Unlike above we provide the input value as an rvalue to the
997	// implicit conversion because this is a OnceAction: it's fine if it
998	// wants to consume the input value.
999	value(ImplicitCast_<U>(std::move(input_value))) {}
1000
1001	// A copy of the value originally provided by the user. We retain this in
1002	// addition to the value of the mock function's result type below in case
1003	// the latter is a reference-like type. See the std::string_view example
1004	// in the documentation on Return.
1005	R input_value;
1006
1007	// The value we actually return, as the type returned by the mock function
1008	// itself.
1009	//
1010	// We eagerly initialize this here, rather than lazily doing the implicit
1011	// conversion automatically each time Perform is called, for historical
1012	// reasons: in 2009-11, commit a070cbd91c (Google changelist 13540126)
1013	// made the Action<U()> conversion operator eagerly convert the R value to
1014	// U, but without keeping the R alive. This broke the use case discussed
1015	// in the documentation for Return, making reference-like types such as
1016	// std::string_view not safe to use as U where the input type R is a
1017	// value-like type such as std::string.
1018	//
1019	// The example the commit gave was not very clear, nor was the issue
1020	// thread (https://github.com/google/googlemock/issues/86), but it seems
1021	// the worry was about reference-like input types R that flatten to a
1022	// value-like type U when being implicitly converted. An example of this
1023	// is std::vector<bool>::reference, which is often a proxy type with an
1024	// reference to the underlying vector:
1025	//
1026	// // Helper method: have the mock function return bools according
1027	// // to the supplied script.
1028	// void SetActions(MockFunction<bool(size_t)>& mock,
1029	// const std::vector<bool>& script) {
1030	// for (size_t i = 0; i < script.size(); ++i) {
1031	// EXPECT_CALL(mock, Call(i)).WillOnce(Return(script[i]));
1032	// }
1033	// }
1034	//
1035	// TEST(Foo, Bar) {
1036	// // Set actions using a temporary vector, whose operator[]
1037	// // returns proxy objects that references that will be
1038	// // dangling once the call to SetActions finishes and the
1039	// // vector is destroyed.
1040	// MockFunction<bool(size_t)> mock;
1041	// SetActions(mock, {false, true});
1042	//
1043	// EXPECT_FALSE(mock.AsStdFunction()(0));
1044	// EXPECT_TRUE(mock.AsStdFunction()(1));
1045	// }
1046	//
1047	// This eager conversion helps with a simple case like this, but doesn't
1048	// fully make these types work in general. For example the following still
1049	// uses a dangling reference:
1050	//
1051	// TEST(Foo, Baz) {
1052	// MockFunction<std::vector<std::string>()> mock;
1053	//
1054	// // Return the same vector twice, and then the empty vector
1055	// // thereafter.
1056	// auto action = Return(std::initializer_list<std::string>{
1057	// "taco", "burrito",
1058	// });
1059	//
1060	// EXPECT_CALL(mock, Call)
1061	// .WillOnce(action)
1062	// .WillOnce(action)
1063	// .WillRepeatedly(Return(std::vector<std::string>{}));
1064	//
1065	// EXPECT_THAT(mock.AsStdFunction()(),
1066	// ElementsAre("taco", "burrito"));
1067	// EXPECT_THAT(mock.AsStdFunction()(),
1068	// ElementsAre("taco", "burrito"));
1069	// EXPECT_THAT(mock.AsStdFunction()(), IsEmpty());
1070	// }
1071	//
1072	U value;
1073	};
1074
1075	const std::shared_ptr<State> state_;
1076	};
1077
1078	R value_;
1079	};
1080
1081	// A specialization of ReturnAction<R> when R is ByMoveWrapper<T> for some T.
1082	//
1083	// This version applies the type system-defeating hack of moving from T even in
1084	// the const call operator, checking at runtime that it isn't called more than
1085	// once, since the user has declared their intent to do so by using ByMove.
1086	template <typename T>
1087	class ReturnAction<ByMoveWrapper<T>> final {
1088	public:
1089	explicit ReturnAction(ByMoveWrapper<T> wrapper)
1090	: state_(new State(std::move(wrapper.payload))) {}
1091
1092	T operator()() const {
1093	GTEST_CHECK_(!state_->called)
1094	<< "A ByMove() action must be performed at most once.";
1095
1096	state_->called = true;
1097	return std::move(state_->value);
1098	}
1099
1100	private:
1101	// We store our state on the heap so that we are copyable as required by
1102	// Action, despite the fact that we are stateful and T may not be copyable.
1103	struct State {
1104	explicit State(T&& value_in) : value(std::move(value_in)) {}
1105
1106	T value;
1107	bool called = false;
1108	};
1109
1110	const std::shared_ptr<State> state_;
1111	};
1112
1113	// Implements the ReturnNull() action.
1114	class ReturnNullAction {
1115	public:
1116	// Allows ReturnNull() to be used in any pointer-returning function. In C++11
1117	// this is enforced by returning nullptr, and in non-C++11 by asserting a
1118	// pointer type on compile time.
1119	template <typename Result, typename ArgumentTuple>
1120	static Result Perform(const ArgumentTuple&) {
1121	return nullptr;
1122	}
1123	};
1124
1125	// Implements the Return() action.
1126	class ReturnVoidAction {
1127	public:
1128	// Allows Return() to be used in any void-returning function.
1129	template <typename Result, typename ArgumentTuple>
1130	static void Perform(const ArgumentTuple&) {
1131	static_assert(std::is_void<Result>::value, "Result should be void.");
1132	}
1133	};
1134
1135	// Implements the polymorphic ReturnRef(x) action, which can be used
1136	// in any function that returns a reference to the type of x,
1137	// regardless of the argument types.
1138	template <typename T>
1139	class ReturnRefAction {
1140	public:
1141	// Constructs a ReturnRefAction object from the reference to be returned.
1142	explicit ReturnRefAction(T& ref) : ref_(ref) {} // NOLINT
1143
1144	// This template type conversion operator allows ReturnRef(x) to be
1145	// used in ANY function that returns a reference to x's type.
1146	template <typename F>
1147	operator Action<F>() const {
1148	typedef typename Function<F>::Result Result;
1149	// Asserts that the function return type is a reference. This
1150	// catches the user error of using ReturnRef(x) when Return(x)
1151	// should be used, and generates some helpful error message.
1152	static_assert(std::is_reference<Result>::value,
1153	"use Return instead of ReturnRef to return a value");
1154	return Action<F>(new Impl<F>(ref_));
1155	}
1156
1157	private:
1158	// Implements the ReturnRef(x) action for a particular function type F.
1159	template <typename F>
1160	class Impl : public ActionInterface<F> {
1161	public:
1162	typedef typename Function<F>::Result Result;
1163	typedef typename Function<F>::ArgumentTuple ArgumentTuple;
1164
1165	explicit Impl(T& ref) : ref_(ref) {} // NOLINT
1166
1167	Result Perform(const ArgumentTuple&) override { return ref_; }
1168
1169	private:
1170	T& ref_;
1171	};
1172
1173	T& ref_;
1174	};
1175
1176	// Implements the polymorphic ReturnRefOfCopy(x) action, which can be
1177	// used in any function that returns a reference to the type of x,
1178	// regardless of the argument types.
1179	template <typename T>
1180	class ReturnRefOfCopyAction {
1181	public:
1182	// Constructs a ReturnRefOfCopyAction object from the reference to
1183	// be returned.
1184	explicit ReturnRefOfCopyAction(const T& value) : value_(value) {} // NOLINT
1185
1186	// This template type conversion operator allows ReturnRefOfCopy(x) to be
1187	// used in ANY function that returns a reference to x's type.
1188	template <typename F>
1189	operator Action<F>() const {
1190	typedef typename Function<F>::Result Result;
1191	// Asserts that the function return type is a reference. This
1192	// catches the user error of using ReturnRefOfCopy(x) when Return(x)
1193	// should be used, and generates some helpful error message.
1194	static_assert(std::is_reference<Result>::value,
1195	"use Return instead of ReturnRefOfCopy to return a value");
1196	return Action<F>(new Impl<F>(value_));
1197	}
1198
1199	private:
1200	// Implements the ReturnRefOfCopy(x) action for a particular function type F.
1201	template <typename F>
1202	class Impl : public ActionInterface<F> {
1203	public:
1204	typedef typename Function<F>::Result Result;
1205	typedef typename Function<F>::ArgumentTuple ArgumentTuple;
1206
1207	explicit Impl(const T& value) : value_(value) {} // NOLINT
1208
1209	Result Perform(const ArgumentTuple&) override { return value_; }
1210
1211	private:
1212	T value_;
1213	};
1214
1215	const T value_;
1216	};
1217
1218	// Implements the polymorphic ReturnRoundRobin(v) action, which can be
1219	// used in any function that returns the element_type of v.
1220	template <typename T>
1221	class ReturnRoundRobinAction {
1222	public:
1223	explicit ReturnRoundRobinAction(std::vector<T> values) {
1224	GTEST_CHECK_(!values.empty())
1225	<< "ReturnRoundRobin requires at least one element.";
1226	state_->values = std::move(values);
1227	}
1228
1229	template <typename... Args>
1230	T operator()(Args&&...) const {
1231	return state_->Next();
1232	}
1233
1234	private:
1235	struct State {
1236	T Next() {
1237	T ret_val = values[i++];
1238	if (i == values.size()) i = `0`;
1239	return ret_val;
1240	}
1241
1242	std::vector<T> values;
1243	size_t i = `0`;
1244	};
1245	std::shared_ptr<State> state_ = std::make_shared<State>();
1246	};
1247
1248	// Implements the polymorphic DoDefault() action.
1249	class DoDefaultAction {
1250	public:
1251	// This template type conversion operator allows DoDefault() to be
1252	// used in any function.
1253	template <typename F>
1254	operator Action<F>() const {
1255	return Action<F>();
1256	} // NOLINT
1257	};
1258
1259	// Implements the Assign action to set a given pointer referent to a
1260	// particular value.
1261	template <typename T1, typename T2>
1262	class AssignAction {
1263	public:
1264	AssignAction(T1* ptr, T2 value) : ptr_(ptr), value_(value) {}
1265
1266	template <typename Result, typename ArgumentTuple>
1267	void Perform(const ArgumentTuple& / args /) const {
1268	*ptr_ = value_;
1269	}
1270
1271	private:
1272	T1* const ptr_;
1273	const T2 value_;
1274	};
1275
1276	#ifndef GTEST_OS_WINDOWS_MOBILE
1277
1278	// Implements the SetErrnoAndReturn action to simulate return from
1279	// various system calls and libc functions.
1280	template <typename T>
1281	class SetErrnoAndReturnAction {
1282	public:
1283	SetErrnoAndReturnAction(int errno_value, T result)
1284	: errno_(errno_value), result_(result) {}
1285	template <typename Result, typename ArgumentTuple>
1286	Result Perform(const ArgumentTuple& / args /) const {
1287	errno = errno_;
1288	return result_;
1289	}
1290
1291	private:
1292	const int errno_;
1293	const T result_;
1294	};
1295
1296	#endif // !GTEST_OS_WINDOWS_MOBILE
1297
1298	// Implements the SetArgumentPointee<N>(x) action for any function
1299	// whose N-th argument (0-based) is a pointer to x's type.
1300	template <size_t N, typename A, typename = void>
1301	struct SetArgumentPointeeAction {
1302	A value;
1303
1304	template <typename... Args>
1305	void operator()(const Args&... args) const {
1306	*::std::get<N>(std::tie(args...)) = value;
1307	}
1308	};
1309
1310	// Implements the Invoke(object_ptr, &Class::Method) action.
1311	template <class Class, typename MethodPtr>
1312	struct InvokeMethodAction {
1313	Class* const obj_ptr;
1314	const MethodPtr method_ptr;
1315
1316	template <typename... Args>
1317	auto operator()(Args&&... args) const
1318	-> decltype((obj_ptr->*method_ptr)(std::forward<Args>(args)...)) {
1319	return (obj_ptr->*method_ptr)(std::forward<Args>(args)...);
1320	}
1321	};
1322
1323	// Implements the InvokeWithoutArgs(f) action. The template argument
1324	// FunctionImpl is the implementation type of f, which can be either a
1325	// function pointer or a functor. InvokeWithoutArgs(f) can be used as an
1326	// Action<F> as long as f's type is compatible with F.
1327	template <typename FunctionImpl>
1328	struct InvokeWithoutArgsAction {
1329	FunctionImpl function_impl;
1330
1331	// Allows InvokeWithoutArgs(f) to be used as any action whose type is
1332	// compatible with f.
1333	template <typename... Args>
1334	auto operator()(const Args&...) -> decltype(function_impl()) {
1335	return function_impl();
1336	}
1337	};
1338
1339	// Implements the InvokeWithoutArgs(object_ptr, &Class::Method) action.
1340	template <class Class, typename MethodPtr>
1341	struct InvokeMethodWithoutArgsAction {
1342	Class* const obj_ptr;
1343	const MethodPtr method_ptr;
1344
1345	using ReturnType =
1346	decltype((std::declval<Class>()->std::declval<MethodPtr>())());
1347
1348	template <typename... Args>
1349	ReturnType operator()(const Args&...) const {
1350	return (obj_ptr->*method_ptr)();
1351	}
1352	};
1353
1354	// Implements the IgnoreResult(action) action.
1355	template <typename A>
1356	class IgnoreResultAction {
1357	public:
1358	explicit IgnoreResultAction(const A& action) : action_(action) {}
1359
1360	template <typename F>
1361	operator Action<F>() const {
1362	// Assert statement belongs here because this is the best place to verify
1363	// conditions on F. It produces the clearest error messages
1364	// in most compilers.
1365	// Impl really belongs in this scope as a local class but can't
1366	// because MSVC produces duplicate symbols in different translation units
1367	// in this case. Until MS fixes that bug we put Impl into the class scope
1368	// and put the typedef both here (for use in assert statement) and
1369	// in the Impl class. But both definitions must be the same.
1370	typedef typename internal::Function<F>::Result Result;
1371
1372	// Asserts at compile time that F returns void.
1373	static_assert(std::is_void<Result>::value, "Result type should be void.");
1374
1375	return Action<F>(new Impl<F>(action_));
1376	}
1377
1378	private:
1379	template <typename F>
1380	class Impl : public ActionInterface<F> {
1381	public:
1382	typedef typename internal::Function<F>::Result Result;
1383	typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
1384
1385	explicit Impl(const A& action) : action_(action) {}
1386
1387	void Perform(const ArgumentTuple& args) override {
1388	// Performs the action and ignores its result.
1389	action_.Perform(args);
1390	}
1391
1392	private:
1393	// Type OriginalFunction is the same as F except that its return
1394	// type is IgnoredValue.
1395	typedef
1396	typename internal::Function<F>::MakeResultIgnoredValue OriginalFunction;
1397
1398	const Action<OriginalFunction> action_;
1399	};
1400
1401	const A action_;
1402	};
1403
1404	template <typename InnerAction, size_t... I>
1405	struct WithArgsAction {
1406	InnerAction inner_action;
1407
1408	// The signature of the function as seen by the inner action, given an out
1409	// action with the given result and argument types.
1410	template <typename R, typename... Args>
1411	using InnerSignature =
1412	R(typename std::tuple_element<I, std::tuple<Args...>>::type...);
1413
1414	// Rather than a call operator, we must define conversion operators to
1415	// particular action types. This is necessary for embedded actions like
1416	// DoDefault(), which rely on an action conversion operators rather than
1417	// providing a call operator because even with a particular set of arguments
1418	// they don't have a fixed return type.
1419
1420	template <
1421	typename R, typename... Args,
1422	typename std::enable_if<
1423	std::is_convertible<InnerAction,
1424	// Unfortunately we can't use the InnerSignature
1425	// alias here; MSVC complains about the I
1426	// parameter pack not being expanded (error C3520)
1427	// despite it being expanded in the type alias.
1428	// TupleElement is also an MSVC workaround.
1429	// See its definition for details.
1430	OnceAction<R(internal::TupleElement<
1431	I, std::tuple<Args...>>...)>>::value,
1432	int>::type = `0`>
1433	operator OnceAction<R(Args...)>() && { // NOLINT
1434	struct OA {
1435	OnceAction<InnerSignature<R, Args...>> inner_action;
1436
1437	R operator()(Args&&... args) && {
1438	return std::move(inner_action)
1439	.Call(std::get<I>(
1440	std::forward_as_tuple(std::forward<Args>(args)...))...);
1441	}
1442	};
1443
1444	return OA{std::move(inner_action)};
1445	}
1446
1447	template <
1448	typename R, typename... Args,
1449	typename std::enable_if<
1450	std::is_convertible<const InnerAction&,
1451	// Unfortunately we can't use the InnerSignature
1452	// alias here; MSVC complains about the I
1453	// parameter pack not being expanded (error C3520)
1454	// despite it being expanded in the type alias.
1455	// TupleElement is also an MSVC workaround.
1456	// See its definition for details.
1457	Action<R(internal::TupleElement<
1458	I, std::tuple<Args...>>...)>>::value,
1459	int>::type = `0`>
1460	operator Action<R(Args...)>() const { // NOLINT
1461	Action<InnerSignature<R, Args...>> converted(inner_action);
1462
1463	return [converted](Args&&... args) -> R {
1464	return converted.Perform(std::forward_as_tuple(
1465	std::get<I>(std::forward_as_tuple(std::forward<Args>(args)...))...));
1466	};
1467	}
1468	};
1469
1470	template <typename... Actions>
1471	class DoAllAction;
1472
1473	// Base case: only a single action.
1474	template <typename FinalAction>
1475	class DoAllAction<FinalAction> {
1476	public:
1477	struct UserConstructorTag {};
1478
1479	template <typename T>
1480	explicit DoAllAction(UserConstructorTag, T&& action)
1481	: final_action_(std::forward<T>(action)) {}
1482
1483	// Rather than a call operator, we must define conversion operators to
1484	// particular action types. This is necessary for embedded actions like
1485	// DoDefault(), which rely on an action conversion operators rather than
1486	// providing a call operator because even with a particular set of arguments
1487	// they don't have a fixed return type.
1488
1489	template <typename R, typename... Args,
1490	typename std::enable_if<
1491	std::is_convertible<FinalAction, OnceAction<R(Args...)>>::value,
1492	int>::type = `0`>
1493	operator OnceAction<R(Args...)>() && { // NOLINT
1494	return std::move(final_action_);
1495	}
1496
1497	template <
1498	typename R, typename... Args,
1499	typename std::enable_if<
1500	std::is_convertible<const FinalAction&, Action<R(Args...)>>::value,
1501	int>::type = `0`>
1502	operator Action<R(Args...)>() const { // NOLINT
1503	return final_action_;
1504	}
1505
1506	private:
1507	FinalAction final_action_;
1508	};
1509
1510	// Recursive case: support N actions by calling the initial action and then
1511	// calling through to the base class containing N-1 actions.
1512	template <typename InitialAction, typename... OtherActions>
1513	class DoAllAction<InitialAction, OtherActions...>
1514	: private DoAllAction<OtherActions...> {
1515	private:
1516	using Base = DoAllAction<OtherActions...>;
1517
1518	// The type of reference that should be provided to an initial action for a
1519	// mocked function parameter of type T.
1520	//
1521	// There are two quirks here:
1522	//
1523	// Unlike most forwarding functions, we pass scalars through by value.*
1524	// This isn't strictly necessary because an lvalue reference would work
1525	// fine too and be consistent with other non-reference types, but it's
1526	// perhaps less surprising.
1527	//
1528	// For example if the mocked function has signature void(int), then it
1529	// might seem surprising for the user's initial action to need to be
1530	// convertible to Action<void(const int&)>. This is perhaps less
1531	// surprising for a non-scalar type where there may be a performance
1532	// impact, or it might even be impossible, to pass by value.
1533	//
1534	// More surprisingly, `const T&` is often not a const reference type.*
1535	// By the reference collapsing rules in C++17 [dcl.ref]/6, if T refers to
1536	// U& or U&& for some non-scalar type U, then InitialActionArgType<T> is
1537	// U&. In other words, we may hand over a non-const reference.
1538	//
1539	// So for example, given some non-scalar type Obj we have the following
1540	// mappings:
1541	//
1542	// T InitialActionArgType<T>
1543	// ------- -----------------------
1544	// Obj const Obj&
1545	// Obj& Obj&
1546	// Obj&& Obj&
1547	// const Obj const Obj&
1548	// const Obj& const Obj&
1549	// const Obj&& const Obj&
1550	//
1551	// In other words, the initial actions get a mutable view of an non-scalar
1552	// argument if and only if the mock function itself accepts a non-const
1553	// reference type. They are never given an rvalue reference to an
1554	// non-scalar type.
1555	//
1556	// This situation makes sense if you imagine use with a matcher that is
1557	// designed to write through a reference. For example, if the caller wants
1558	// to fill in a reference argument and then return a canned value:
1559	//
1560	// EXPECT_CALL(mock, Call)
1561	// .WillOnce(DoAll(SetArgReferee<0>(17), Return(19)));
1562	//
1563	template <typename T>
1564	using InitialActionArgType =
1565	typename std::conditional<std::is_scalar<T>::value, T, const T&>::type;
1566
1567	public:
1568	struct UserConstructorTag {};
1569
1570	template <typename T, typename... U>
1571	explicit DoAllAction(UserConstructorTag, T&& initial_action,
1572	U&&... other_actions)
1573	: Base({}, std::forward<U>(other_actions)...),
1574	initial_action_(std::forward<T>(initial_action)) {}
1575
1576	template <typename R, typename... Args,
1577	typename std::enable_if<
1578	conjunction<
1579	// Both the initial action and the rest must support
1580	// conversion to OnceAction.
1581	std::is_convertible<
1582	InitialAction,
1583	OnceAction<void(InitialActionArgType<Args>...)>>,
1584	std::is_convertible<Base, OnceAction<R(Args...)>>>::value,
1585	int>::type = `0`>
1586	operator OnceAction<R(Args...)>() && { // NOLINT
1587	// Return an action that first calls the initial action with arguments
1588	// filtered through InitialActionArgType, then forwards arguments directly
1589	// to the base class to deal with the remaining actions.
1590	struct OA {
1591	OnceAction<void(InitialActionArgType<Args>...)> initial_action;
1592	OnceAction<R(Args...)> remaining_actions;
1593
1594	R operator()(Args... args) && {
1595	std::move(initial_action)
1596	.Call(static_cast<InitialActionArgType<Args>>(args)...);
1597
1598	return std::move(remaining_actions).Call(std::forward<Args>(args)...);
1599	}
1600	};
1601
1602	return OA{
1603	std::move(initial_action_),
1604	std::move(static_cast<Base&>(*this)),
1605	};
1606	}
1607
1608	template <
1609	typename R, typename... Args,
1610	typename std::enable_if<
1611	conjunction<
1612	// Both the initial action and the rest must support conversion to
1613	// Action.
1614	std::is_convertible<const InitialAction&,
1615	Action<void(InitialActionArgType<Args>...)>>,
1616	std::is_convertible<const Base&, Action<R(Args...)>>>::value,
1617	int>::type = `0`>
1618	operator Action<R(Args...)>() const { // NOLINT
1619	// Return an action that first calls the initial action with arguments
1620	// filtered through InitialActionArgType, then forwards arguments directly
1621	// to the base class to deal with the remaining actions.
1622	struct OA {
1623	Action<void(InitialActionArgType<Args>...)> initial_action;
1624	Action<R(Args...)> remaining_actions;
1625
1626	R operator()(Args... args) const {
1627	initial_action.Perform(std::forward_as_tuple(
1628	static_cast<InitialActionArgType<Args>>(args)...));
1629
1630	return remaining_actions.Perform(
1631	std::forward_as_tuple(std::forward<Args>(args)...));
1632	}
1633	};
1634
1635	return OA{
1636	initial_action_,
1637	static_cast<const Base&>(*this),
1638	};
1639	}
1640
1641	private:
1642	InitialAction initial_action_;
1643	};
1644
1645	template <typename T, typename... Params>
1646	struct ReturnNewAction {
1647	T* operator()() const {
1648	return internal::Apply(
1649	[](const Params&... unpacked_params) {
1650	return new T(unpacked_params...);
1651	},
1652	params);
1653	}
1654	std::tuple<Params...> params;
1655	};
1656
1657	template <size_t k>
1658	struct ReturnArgAction {
1659	template <typename... Args,
1660	typename = typename std::enable_if<(k < sizeof...(Args))>::type>
1661	auto operator()(Args&&... args) const -> decltype(std::get<k>(
1662	std::forward_as_tuple(std::forward<Args>(args)...))) {
1663	return std::get<k>(std::forward_as_tuple(std::forward<Args>(args)...));
1664	}
1665	};
1666
1667	template <size_t k, typename Ptr>
1668	struct SaveArgAction {
1669	Ptr pointer;
1670
1671	template <typename... Args>
1672	void operator()(const Args&... args) const {
1673	*pointer = std::get<k>(std::tie(args...));
1674	}
1675	};
1676
1677	template <size_t k, typename Ptr>
1678	struct SaveArgPointeeAction {
1679	Ptr pointer;
1680
1681	template <typename... Args>
1682	void operator()(const Args&... args) const {
1683	pointer = std::get<k>(std::tie(args...));
1684	}
1685	};
1686
1687	template <size_t k, typename T>
1688	struct SetArgRefereeAction {
1689	T value;
1690
1691	template <typename... Args>
1692	void operator()(Args&&... args) const {
1693	using argk_type =
1694	typename ::std::tuple_element<k, std::tuple<Args...>>::type;
1695	static_assert(std::is_lvalue_reference<argk_type>::value,
1696	"Argument must be a reference type.");
1697	std::get<k>(std::tie(args...)) = value;
1698	}
1699	};
1700
1701	template <size_t k, typename I1, typename I2>
1702	struct SetArrayArgumentAction {
1703	I1 first;
1704	I2 last;
1705
1706	template <typename... Args>
1707	void operator()(const Args&... args) const {
1708	auto value = std::get<k>(std::tie(args...));
1709	for (auto it = first; it != last; ++it, (void)++value) {
1710	value = it;
1711	}
1712	}
1713	};
1714
1715	template <size_t k>
1716	struct DeleteArgAction {
1717	template <typename... Args>
1718	void operator()(const Args&... args) const {
1719	delete std::get<k>(std::tie(args...));
1720	}
1721	};
1722
1723	template <typename Ptr>
1724	struct ReturnPointeeAction {
1725	Ptr pointer;
1726	template <typename... Args>
1727	auto operator()(const Args&...) const -> decltype(*pointer) {
1728	return *pointer;
1729	}
1730	};
1731
1732	#if GTEST_HAS_EXCEPTIONS
1733	template <typename T>
1734	struct ThrowAction {
1735	T exception;
1736	// We use a conversion operator to adapt to any return type.
1737	template <typename R, typename... Args>
1738	operator Action<R(Args...)>() const { // NOLINT
1739	T copy = exception;
1740	return [copy](Args...) -> R { throw copy; };
1741	}
1742	};
1743	#endif // GTEST_HAS_EXCEPTIONS
1744
1745	} // namespace internal
1746
1747	// An Unused object can be implicitly constructed from ANY value.
1748	// This is handy when defining actions that ignore some or all of the
1749	// mock function arguments. For example, given
1750	//
1751	// MOCK_METHOD3(Foo, double(const string& label, double x, double y));
1752	// MOCK_METHOD3(Bar, double(int index, double x, double y));
1753	//
1754	// instead of
1755	//
1756	// double DistanceToOriginWithLabel(const string& label, double x, double y) {
1757	// return sqrt(xx + yy);
1758	// }
1759	// double DistanceToOriginWithIndex(int index, double x, double y) {
1760	// return sqrt(xx + yy);
1761	// }
1762	// ...
1763	// EXPECT_CALL(mock, Foo("abc", _, _))
1764	// .WillOnce(Invoke(DistanceToOriginWithLabel));
1765	// EXPECT_CALL(mock, Bar(5, _, _))
1766	// .WillOnce(Invoke(DistanceToOriginWithIndex));
1767	//
1768	// you could write
1769	//
1770	// // We can declare any uninteresting argument as Unused.
1771	// double DistanceToOrigin(Unused, double x, double y) {
1772	// return sqrt(xx + yy);
1773	// }
1774	// ...
1775	// EXPECT_CALL(mock, Foo("abc", _, _)).WillOnce(Invoke(DistanceToOrigin));
1776	// EXPECT_CALL(mock, Bar(5, _, _)).WillOnce(Invoke(DistanceToOrigin));
1777	typedef internal::IgnoredValue Unused;
1778
1779	// Creates an action that does actions a1, a2, ..., sequentially in
1780	// each invocation. All but the last action will have a readonly view of the
1781	// arguments.
1782	template <typename... Action>
1783	internal::DoAllAction<typename std::decay<Action>::type...> DoAll(
1784	Action&&... action) {
1785	return internal::DoAllAction<typename std::decay<Action>::type...>(
1786	{}, std::forward<Action>(action)...);
1787	}
1788
1789	// WithArg<k>(an_action) creates an action that passes the k-th
1790	// (0-based) argument of the mock function to an_action and performs
1791	// it. It adapts an action accepting one argument to one that accepts
1792	// multiple arguments. For convenience, we also provide
1793	// WithArgs<k>(an_action) (defined below) as a synonym.
1794	template <size_t k, typename InnerAction>
1795	internal::WithArgsAction<typename std::decay<InnerAction>::type, k> WithArg(
1796	InnerAction&& action) {
1797	return {std::forward<InnerAction>(action)};
1798	}
1799
1800	// WithArgs<N1, N2, ..., Nk>(an_action) creates an action that passes
1801	// the selected arguments of the mock function to an_action and
1802	// performs it. It serves as an adaptor between actions with
1803	// different argument lists.
1804	template <size_t k, size_t... ks, typename InnerAction>
1805	internal::WithArgsAction<typename std::decay<InnerAction>::type, k, ks...>
1806	WithArgs(InnerAction&& action) {
1807	return {std::forward<InnerAction>(action)};
1808	}
1809
1810	// WithoutArgs(inner_action) can be used in a mock function with a
1811	// non-empty argument list to perform inner_action, which takes no
1812	// argument. In other words, it adapts an action accepting no
1813	// argument to one that accepts (and ignores) arguments.
1814	template <typename InnerAction>
1815	internal::WithArgsAction<typename std::decay<InnerAction>::type> WithoutArgs(
1816	InnerAction&& action) {
1817	return {std::forward<InnerAction>(action)};
1818	}
1819
1820	// Creates an action that returns a value.
1821	//
1822	// The returned type can be used with a mock function returning a non-void,
1823	// non-reference type U as follows:
1824	//
1825	// If R is convertible to U and U is move-constructible, then the action can*
1826	// be used with WillOnce.
1827	//
1828	// If const R& is convertible to U and U is copy-constructible, then the*
1829	// action can be used with both WillOnce and WillRepeatedly.
1830	//
1831	// The mock expectation contains the R value from which the U return value is
1832	// constructed (a move/copy of the argument to Return). This means that the R
1833	// value will survive at least until the mock object's expectations are cleared
1834	// or the mock object is destroyed, meaning that U can safely be a
1835	// reference-like type such as std::string_view:
1836	//
1837	// // The mock function returns a view of a copy of the string fed to
1838	// // Return. The view is valid even after the action is performed.
1839	// MockFunction<std::string_view()> mock;
1840	// EXPECT_CALL(mock, Call).WillOnce(Return(std::string("taco")));
1841	// const std::string_view result = mock.AsStdFunction()();
1842	// EXPECT_EQ("taco", result);
1843	//
1844	template <typename R>
1845	internal::ReturnAction<R> Return(R value) {
1846	return internal::ReturnAction<R>(std::move(value));
1847	}
1848
1849	// Creates an action that returns NULL.
1850	inline PolymorphicAction<internal::ReturnNullAction> ReturnNull() {
1851	return MakePolymorphicAction(impl: internal::ReturnNullAction ());
1852	}
1853
1854	// Creates an action that returns from a void function.
1855	inline PolymorphicAction<internal::ReturnVoidAction> Return() {
1856	return MakePolymorphicAction(impl: internal::ReturnVoidAction ());
1857	}
1858
1859	// Creates an action that returns the reference to a variable.
1860	template <typename R>
1861	inline internal::ReturnRefAction<R> ReturnRef(R& x) { // NOLINT
1862	return internal::ReturnRefAction<R>(x);
1863	}
1864
1865	// Prevent using ReturnRef on reference to temporary.
1866	template <typename R, R* = nullptr>
1867	internal::ReturnRefAction<R> ReturnRef(R&&) = delete;
1868
1869	// Creates an action that returns the reference to a copy of the
1870	// argument. The copy is created when the action is constructed and
1871	// lives as long as the action.
1872	template <typename R>
1873	inline internal::ReturnRefOfCopyAction<R> ReturnRefOfCopy(const R& x) {
1874	return internal::ReturnRefOfCopyAction<R>(x);
1875	}
1876
1877	// DEPRECATED: use Return(x) directly with WillOnce.
1878	//
1879	// Modifies the parent action (a Return() action) to perform a move of the
1880	// argument instead of a copy.
1881	// Return(ByMove()) actions can only be executed once and will assert this
1882	// invariant.
1883	template <typename R>
1884	internal::ByMoveWrapper<R> ByMove(R x) {
1885	return internal::ByMoveWrapper<R>(std::move(x));
1886	}
1887
1888	// Creates an action that returns an element of `vals`. Calling this action will
1889	// repeatedly return the next value from `vals` until it reaches the end and
1890	// will restart from the beginning.
1891	template <typename T>
1892	internal::ReturnRoundRobinAction<T> ReturnRoundRobin(std::vector<T> vals) {
1893	return internal::ReturnRoundRobinAction<T>(std::move(vals));
1894	}
1895
1896	// Creates an action that returns an element of `vals`. Calling this action will
1897	// repeatedly return the next value from `vals` until it reaches the end and
1898	// will restart from the beginning.
1899	template <typename T>
1900	internal::ReturnRoundRobinAction<T> ReturnRoundRobin(
1901	std::initializer_list<T> vals) {
1902	return internal::ReturnRoundRobinAction<T>(std::vector<T>(vals));
1903	}
1904
1905	// Creates an action that does the default action for the give mock function.
1906	inline internal::DoDefaultAction DoDefault() {
1907	return internal::DoDefaultAction ();
1908	}
1909
1910	// Creates an action that sets the variable pointed by the N-th
1911	// (0-based) function argument to 'value'.
1912	template <size_t N, typename T>
1913	internal::SetArgumentPointeeAction<N, T> SetArgPointee(T value) {
1914	return {std::move(value)};
1915	}
1916
1917	// The following version is DEPRECATED.
1918	template <size_t N, typename T>
1919	internal::SetArgumentPointeeAction<N, T> SetArgumentPointee(T value) {
1920	return {std::move(value)};
1921	}
1922
1923	// Creates an action that sets a pointer referent to a given value.
1924	template <typename T1, typename T2>
1925	PolymorphicAction<internal::AssignAction<T1, T2>> Assign(T1* ptr, T2 val) {
1926	return MakePolymorphicAction(internal::AssignAction<T1, T2>(ptr, val));
1927	}
1928
1929	#ifndef GTEST_OS_WINDOWS_MOBILE
1930
1931	// Creates an action that sets errno and returns the appropriate error.
1932	template <typename T>
1933	PolymorphicAction<internal::SetErrnoAndReturnAction<T>> SetErrnoAndReturn(
1934	int errval, T result) {
1935	return MakePolymorphicAction(
1936	internal::SetErrnoAndReturnAction<T>(errval, result));
1937	}
1938
1939	#endif // !GTEST_OS_WINDOWS_MOBILE
1940
1941	// Various overloads for Invoke().
1942
1943	// Legacy function.
1944	// Actions can now be implicitly constructed from callables. No need to create
1945	// wrapper objects.
1946	// This function exists for backwards compatibility.
1947	template <typename FunctionImpl>
1948	typename std::decay<FunctionImpl>::type Invoke(FunctionImpl&& function_impl) {
1949	return std::forward<FunctionImpl>(function_impl);
1950	}
1951
1952	// Creates an action that invokes the given method on the given object
1953	// with the mock function's arguments.
1954	template <class Class, typename MethodPtr>
1955	internal::InvokeMethodAction<Class, MethodPtr> Invoke(Class* obj_ptr,
1956	MethodPtr method_ptr) {
1957	return {obj_ptr, method_ptr};
1958	}
1959
1960	// Creates an action that invokes 'function_impl' with no argument.
1961	template <typename FunctionImpl>
1962	internal::InvokeWithoutArgsAction<typename std::decay<FunctionImpl>::type>
1963	InvokeWithoutArgs(FunctionImpl function_impl) {
1964	return {std::move(function_impl)};
1965	}
1966
1967	// Creates an action that invokes the given method on the given object
1968	// with no argument.
1969	template <class Class, typename MethodPtr>
1970	internal::InvokeMethodWithoutArgsAction<Class, MethodPtr> InvokeWithoutArgs(
1971	Class* obj_ptr, MethodPtr method_ptr) {
1972	return {obj_ptr, method_ptr};
1973	}
1974
1975	// Creates an action that performs an_action and throws away its
1976	// result. In other words, it changes the return type of an_action to
1977	// void. an_action MUST NOT return void, or the code won't compile.
1978	template <typename A>
1979	inline internal::IgnoreResultAction<A> IgnoreResult(const A& an_action) {
1980	return internal::IgnoreResultAction<A>(an_action);
1981	}
1982
1983	// Creates a reference wrapper for the given L-value. If necessary,
1984	// you can explicitly specify the type of the reference. For example,
1985	// suppose 'derived' is an object of type Derived, ByRef(derived)
1986	// would wrap a Derived&. If you want to wrap a const Base& instead,
1987	// where Base is a base class of Derived, just write:
1988	//
1989	// ByRef<const Base>(derived)
1990	//
1991	// N.B. ByRef is redundant with std::ref, std::cref and std::reference_wrapper.
1992	// However, it may still be used for consistency with ByMove().
1993	template <typename T>
1994	inline ::std::reference_wrapper<T> ByRef(T& l_value) { // NOLINT
1995	return ::std::reference_wrapper<T>(l_value);
1996	}
1997
1998	// The ReturnNew<T>(a1, a2, ..., a_k) action returns a pointer to a new
1999	// instance of type T, constructed on the heap with constructor arguments
2000	// a1, a2, ..., and a_k. The caller assumes ownership of the returned value.
2001	template <typename T, typename... Params>
2002	internal::ReturnNewAction<T, typename std::decay<Params>::type...> ReturnNew(
2003	Params&&... params) {
2004	return {std::forward_as_tuple(std::forward<Params>(params)...)};
2005	}
2006
2007	// Action ReturnArg<k>() returns the k-th argument of the mock function.
2008	template <size_t k>
2009	internal::ReturnArgAction<k> ReturnArg() {
2010	return {};
2011	}
2012
2013	// Action SaveArg<k>(pointer) saves the k-th (0-based) argument of the
2014	// mock function to pointer.*
2015	template <size_t k, typename Ptr>
2016	internal::SaveArgAction<k, Ptr> SaveArg(Ptr pointer) {
2017	return {pointer};
2018	}
2019
2020	// Action SaveArgPointee<k>(pointer) saves the value pointed to
2021	// by the k-th (0-based) argument of the mock function to pointer.*
2022	template <size_t k, typename Ptr>
2023	internal::SaveArgPointeeAction<k, Ptr> SaveArgPointee(Ptr pointer) {
2024	return {pointer};
2025	}
2026
2027	// Action SetArgReferee<k>(value) assigns 'value' to the variable
2028	// referenced by the k-th (0-based) argument of the mock function.
2029	template <size_t k, typename T>
2030	internal::SetArgRefereeAction<k, typename std::decay<T>::type> SetArgReferee(
2031	T&& value) {
2032	return {std::forward<T>(value)};
2033	}
2034
2035	// Action SetArrayArgument<k>(first, last) copies the elements in
2036	// source range [first, last) to the array pointed to by the k-th
2037	// (0-based) argument, which can be either a pointer or an
2038	// iterator. The action does not take ownership of the elements in the
2039	// source range.
2040	template <size_t k, typename I1, typename I2>
2041	internal::SetArrayArgumentAction<k, I1, I2> SetArrayArgument(I1 first,
2042	I2 last) {
2043	return {first, last};
2044	}
2045
2046	// Action DeleteArg<k>() deletes the k-th (0-based) argument of the mock
2047	// function.
2048	template <size_t k>
2049	internal::DeleteArgAction<k> DeleteArg() {
2050	return {};
2051	}
2052
2053	// This action returns the value pointed to by 'pointer'.
2054	template <typename Ptr>
2055	internal::ReturnPointeeAction<Ptr> ReturnPointee(Ptr pointer) {
2056	return {pointer};
2057	}
2058
2059	// Action Throw(exception) can be used in a mock function of any type
2060	// to throw the given exception. Any copyable value can be thrown.
2061	#if GTEST_HAS_EXCEPTIONS
2062	template <typename T>
2063	internal::ThrowAction<typename std::decay<T>::type> Throw(T&& exception) {
2064	return {std::forward<T>(exception)};
2065	}
2066	#endif // GTEST_HAS_EXCEPTIONS
2067
2068	namespace internal {
2069
2070	// A macro from the ACTION family (defined later in gmock-generated-actions.h)*
2071	// defines an action that can be used in a mock function. Typically,
2072	// these actions only care about a subset of the arguments of the mock
2073	// function. For example, if such an action only uses the second
2074	// argument, it can be used in any mock function that takes >= 2
2075	// arguments where the type of the second argument is compatible.
2076	//
2077	// Therefore, the action implementation must be prepared to take more
2078	// arguments than it needs. The ExcessiveArg type is used to
2079	// represent those excessive arguments. In order to keep the compiler
2080	// error messages tractable, we define it in the testing namespace
2081	// instead of testing::internal. However, this is an INTERNAL TYPE
2082	// and subject to change without notice, so a user MUST NOT USE THIS
2083	// TYPE DIRECTLY.
2084	struct ExcessiveArg {};
2085
2086	// Builds an implementation of an Action<> for some particular signature, using
2087	// a class defined by an ACTION macro.*
2088	template <typename F, typename Impl>
2089	struct ActionImpl;
2090
2091	template <typename Impl>
2092	struct ImplBase {
2093	struct Holder {
2094	// Allows each copy of the Action<> to get to the Impl.
2095	explicit operator const Impl&() const { return *ptr; }
2096	std::shared_ptr<Impl> ptr;
2097	};
2098	using type = typename std::conditional<std::is_constructible<Impl>::value,
2099	Impl, Holder>::type;
2100	};
2101
2102	template <typename R, typename... Args, typename Impl>
2103	struct ActionImpl<R(Args...), Impl> : ImplBase<Impl>::type {
2104	using Base = typename ImplBase<Impl>::type;
2105	using function_type = R(Args...);
2106	using args_type = std::tuple<Args...>;
2107
2108	ActionImpl() = default; // Only defined if appropriate for Base.
2109	explicit ActionImpl(std::shared_ptr<Impl> impl) : Base{std::move(impl)} {}
2110
2111	R operator()(Args&&... arg) const {
2112	static constexpr size_t kMaxArgs =
2113	sizeof...(Args) <= `10` ? sizeof...(Args) : `10`;
2114	return Apply(MakeIndexSequence<kMaxArgs>{},
2115	MakeIndexSequence<`10` - kMaxArgs>{},
2116	args_type{std::forward<Args>(arg)...});
2117	}
2118
2119	template <std::size_t... arg_id, std::size_t... excess_id>
2120	R Apply(IndexSequence<arg_id...>, IndexSequence<excess_id...>,
2121	const args_type& args) const {
2122	// Impl need not be specific to the signature of action being implemented;
2123	// only the implementing function body needs to have all of the specific
2124	// types instantiated. Up to 10 of the args that are provided by the
2125	// args_type get passed, followed by a dummy of unspecified type for the
2126	// remainder up to 10 explicit args.
2127	static constexpr ExcessiveArg kExcessArg{};
2128	return static_cast<const Impl&>(*this)
2129	.template gmock_PerformImpl<
2130	/function_type=/function_type, /return_type=/R,
2131	/args_type=/args_type,
2132	/argN_type=/
2133	typename std::tuple_element<arg_id, args_type>::type...>(
2134	/args=/args, std::get<arg_id>(args)...,
2135	((void)excess_id, kExcessArg)...);
2136	}
2137	};
2138
2139	// Stores a default-constructed Impl as part of the Action<>'s
2140	// std::function<>. The Impl should be trivial to copy.
2141	template <typename F, typename Impl>
2142	::testing::Action<F> MakeAction() {
2143	return ::testing::Action<F>(ActionImpl<F, Impl>());
2144	}
2145
2146	// Stores just the one given instance of Impl.
2147	template <typename F, typename Impl>
2148	::testing::Action<F> MakeAction(std::shared_ptr<Impl> impl) {
2149	return ::testing::Action<F>(ActionImpl<F, Impl>(std::move(impl)));
2150	}
2151
2152	#define GMOCK_INTERNAL_ARG_UNUSED(i, data, el) \
2153	, const arg##i##_type& arg##i GTEST_ATTRIBUTE_UNUSED_
2154	#define GMOCK_ACTION_ARG_TYPES_AND_NAMES_UNUSED_ \
2155	const args_type& args GTEST_ATTRIBUTE_UNUSED_ GMOCK_PP_REPEAT( \
2156	GMOCK_INTERNAL_ARG_UNUSED, , 10)
2157
2158	#define GMOCK_INTERNAL_ARG(i, data, el) , const arg##i##_type& arg##i
2159	#define GMOCK_ACTION_ARG_TYPES_AND_NAMES_ \
2160	const args_type& args GMOCK_PP_REPEAT(GMOCK_INTERNAL_ARG, , 10)
2161
2162	#define GMOCK_INTERNAL_TEMPLATE_ARG(i, data, el) , typename arg##i##_type
2163	#define GMOCK_ACTION_TEMPLATE_ARGS_NAMES_ \
2164	GMOCK_PP_TAIL(GMOCK_PP_REPEAT(GMOCK_INTERNAL_TEMPLATE_ARG, , 10))
2165
2166	#define GMOCK_INTERNAL_TYPENAME_PARAM(i, data, param) , typename param##_type
2167	#define GMOCK_ACTION_TYPENAME_PARAMS_(params) \
2168	GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_TYPENAME_PARAM, , params))
2169
2170	#define GMOCK_INTERNAL_TYPE_PARAM(i, data, param) , param##_type
2171	#define GMOCK_ACTION_TYPE_PARAMS_(params) \
2172	GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_TYPE_PARAM, , params))
2173
2174	#define GMOCK_INTERNAL_TYPE_GVALUE_PARAM(i, data, param) \
2175	, param##_type gmock_p##i
2176	#define GMOCK_ACTION_TYPE_GVALUE_PARAMS_(params) \
2177	GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_TYPE_GVALUE_PARAM, , params))
2178
2179	#define GMOCK_INTERNAL_GVALUE_PARAM(i, data, param) \
2180	, std::forward<param##_type>(gmock_p##i)
2181	#define GMOCK_ACTION_GVALUE_PARAMS_(params) \
2182	GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_GVALUE_PARAM, , params))
2183
2184	#define GMOCK_INTERNAL_INIT_PARAM(i, data, param) \
2185	, param(::std::forward<param##_type>(gmock_p##i))
2186	#define GMOCK_ACTION_INIT_PARAMS_(params) \
2187	GMOCK_PP_TAIL(GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_INIT_PARAM, , params))
2188
2189	#define GMOCK_INTERNAL_FIELD_PARAM(i, data, param) param##_type param;
2190	#define GMOCK_ACTION_FIELD_PARAMS_(params) \
2191	GMOCK_PP_FOR_EACH(GMOCK_INTERNAL_FIELD_PARAM, , params)
2192
2193	#define GMOCK_INTERNAL_ACTION(name, full_name, params) \
2194	template <GMOCK_ACTION_TYPENAME_PARAMS_(params)> \
2195	class full_name { \
2196	public: \
2197	explicit full_name(GMOCK_ACTION_TYPE_GVALUE_PARAMS_(params)) \
2198	: impl_(std::make_shared<gmock_Impl>( \
2199	GMOCK_ACTION_GVALUE_PARAMS_(params))) {} \
2200	full_name(const full_name&) = default; \
2201	full_name(full_name&&) noexcept = default; \
2202	template <typename F> \
2203	operator ::testing::Action<F>() const { \
2204	return ::testing::internal::MakeAction<F>(impl_); \
2205	} \
2206	\
2207	private: \
2208	class gmock_Impl { \
2209	public: \
2210	explicit gmock_Impl(GMOCK_ACTION_TYPE_GVALUE_PARAMS_(params)) \
2211	: GMOCK_ACTION_INIT_PARAMS_(params) {} \
2212	template <typename function_type, typename return_type, \
2213	typename args_type, GMOCK_ACTION_TEMPLATE_ARGS_NAMES_> \
2214	return_type gmock_PerformImpl(GMOCK_ACTION_ARG_TYPES_AND_NAMES_) const; \
2215	GMOCK_ACTION_FIELD_PARAMS_(params) \
2216	}; \
2217	std::shared_ptr<const gmock_Impl> impl_; \
2218	}; \
2219	template <GMOCK_ACTION_TYPENAME_PARAMS_(params)> \
2220	inline full_name<GMOCK_ACTION_TYPE_PARAMS_(params)> name( \
2221	GMOCK_ACTION_TYPE_GVALUE_PARAMS_(params)) GTEST_MUST_USE_RESULT_; \
2222	template <GMOCK_ACTION_TYPENAME_PARAMS_(params)> \
2223	inline full_name<GMOCK_ACTION_TYPE_PARAMS_(params)> name( \
2224	GMOCK_ACTION_TYPE_GVALUE_PARAMS_(params)) { \
2225	return full_name<GMOCK_ACTION_TYPE_PARAMS_(params)>( \
2226	GMOCK_ACTION_GVALUE_PARAMS_(params)); \
2227	} \
2228	template <GMOCK_ACTION_TYPENAME_PARAMS_(params)> \
2229	template <typename function_type, typename return_type, typename args_type, \
2230	GMOCK_ACTION_TEMPLATE_ARGS_NAMES_> \
2231	return_type \
2232	full_name<GMOCK_ACTION_TYPE_PARAMS_(params)>::gmock_Impl::gmock_PerformImpl( \
2233	GMOCK_ACTION_ARG_TYPES_AND_NAMES_UNUSED_) const
2234
2235	} // namespace internal
2236
2237	// Similar to GMOCK_INTERNAL_ACTION, but no bound parameters are stored.
2238	#define ACTION(name) \
2239	class name##Action { \
2240	public: \
2241	explicit name##Action() noexcept {} \
2242	name##Action(const name##Action&) noexcept {} \
2243	template <typename F> \
2244	operator ::testing::Action<F>() const { \
2245	return ::testing::internal::MakeAction<F, gmock_Impl>(); \
2246	} \
2247	\
2248	private: \
2249	class gmock_Impl { \
2250	public: \
2251	template <typename function_type, typename return_type, \
2252	typename args_type, GMOCK_ACTION_TEMPLATE_ARGS_NAMES_> \
2253	return_type gmock_PerformImpl(GMOCK_ACTION_ARG_TYPES_AND_NAMES_) const; \
2254	}; \
2255	}; \
2256	inline name##Action name() GTEST_MUST_USE_RESULT_; \
2257	inline name##Action name() { return name##Action(); } \
2258	template <typename function_type, typename return_type, typename args_type, \
2259	GMOCK_ACTION_TEMPLATE_ARGS_NAMES_> \
2260	return_type name##Action::gmock_Impl::gmock_PerformImpl( \
2261	GMOCK_ACTION_ARG_TYPES_AND_NAMES_UNUSED_) const
2262
2263	#define ACTION_P(name, ...) \
2264	GMOCK_INTERNAL_ACTION(name, name##ActionP, (__VA_ARGS__))
2265
2266	#define ACTION_P2(name, ...) \
2267	GMOCK_INTERNAL_ACTION(name, name##ActionP2, (__VA_ARGS__))
2268
2269	#define ACTION_P3(name, ...) \
2270	GMOCK_INTERNAL_ACTION(name, name##ActionP3, (__VA_ARGS__))
2271
2272	#define ACTION_P4(name, ...) \
2273	GMOCK_INTERNAL_ACTION(name, name##ActionP4, (__VA_ARGS__))
2274
2275	#define ACTION_P5(name, ...) \
2276	GMOCK_INTERNAL_ACTION(name, name##ActionP5, (__VA_ARGS__))
2277
2278	#define ACTION_P6(name, ...) \
2279	GMOCK_INTERNAL_ACTION(name, name##ActionP6, (__VA_ARGS__))
2280
2281	#define ACTION_P7(name, ...) \
2282	GMOCK_INTERNAL_ACTION(name, name##ActionP7, (__VA_ARGS__))
2283
2284	#define ACTION_P8(name, ...) \
2285	GMOCK_INTERNAL_ACTION(name, name##ActionP8, (__VA_ARGS__))
2286
2287	#define ACTION_P9(name, ...) \
2288	GMOCK_INTERNAL_ACTION(name, name##ActionP9, (__VA_ARGS__))
2289
2290	#define ACTION_P10(name, ...) \
2291	GMOCK_INTERNAL_ACTION(name, name##ActionP10, (__VA_ARGS__))
2292
2293	} // namespace testing
2294
2295	GTEST_DISABLE_MSC_WARNINGS_POP_() // 4100
2296
2297	#endif // GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_ACTIONS_H_
2298

Browse the source code of include/gmock/gmock-actions.h