diff options
Diffstat (limited to 'googlemock/include')
| -rw-r--r-- | googlemock/include/gmock/gmock-actions.h | 269 | ||||
| -rw-r--r-- | googlemock/include/gmock/gmock-spec-builders.h | 8 |
2 files changed, 271 insertions, 6 deletions
diff --git a/googlemock/include/gmock/gmock-actions.h b/googlemock/include/gmock/gmock-actions.h index 2c4ce36..4ae18da 100644 --- a/googlemock/include/gmock/gmock-actions.h +++ b/googlemock/include/gmock/gmock-actions.h @@ -262,9 +262,65 @@ GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(double, 0); #undef GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_ -// Simple two-arg form of std::disjunction. -template <typename P, typename Q> -using disjunction = typename ::std::conditional<P::value, P, Q>::type; +// Partial implementations of metaprogramming types from the standard library +// not available in C++11. + +template <typename P> +struct negation + // NOLINTNEXTLINE + : std::integral_constant<bool, bool(!P::value)> {}; + +// Base case: with zero predicates the answer is always true. +template <typename...> +struct conjunction : std::true_type {}; + +// With a single predicate, the answer is that predicate. +template <typename P1> +struct conjunction<P1> : P1 {}; + +// With multiple predicates the answer is the first predicate if that is false, +// and we recurse otherwise. +template <typename P1, typename... Ps> +struct conjunction<P1, Ps...> + : std::conditional<bool(P1::value), conjunction<Ps...>, P1>::type {}; + +template <typename...> +struct disjunction : std::false_type {}; + +template <typename P1> +struct disjunction<P1> : P1 {}; + +template <typename P1, typename... Ps> +struct disjunction<P1, Ps...> + // NOLINTNEXTLINE + : std::conditional<!bool(P1::value), disjunction<Ps...>, P1>::type {}; + +template <typename...> +using void_t = void; + +// Like std::invoke_result_t from C++17, but works only for objects with call +// operators (not e.g. member function pointers, which we don't need specific +// support for in OnceAction because std::function deals with them). +template <typename F, typename... Args> +using call_result_t = decltype(std::declval<F>()(std::declval<Args>()...)); + +template <typename Void, typename R, typename F, typename... Args> +struct is_callable_r_impl : std::false_type {}; + +// Specialize the struct for those template arguments where call_result_t is +// well-formed. When it's not, the generic template above is chosen, resulting +// in std::false_type. +template <typename R, typename F, typename... Args> +struct is_callable_r_impl<void_t<call_result_t<F, Args...>>, R, F, Args...> + : std::conditional< + std::is_same<R, void>::value, // + std::true_type, // + std::is_convertible<call_result_t<F, Args...>, R>>::type {}; + +// Like std::is_invocable_r from C++17, but works only for objects with call +// operators. See the note on call_result_t. +template <typename R, typename F, typename... Args> +using is_callable_r = is_callable_r_impl<void, R, F, Args...>; } // namespace internal @@ -596,6 +652,213 @@ inline PolymorphicAction<Impl> MakePolymorphicAction(const Impl& impl) { namespace internal { +template <typename F> +class TypedExpectation; + +// Specialized for function types below. +template <typename F> +class OnceAction; + +// An action that can only be used once. +// +// This is what is accepted by WillOnce, which doesn't require the underlying +// action to be copy-constructible (only move-constructible), and promises to +// invoke it as an rvalue reference. This allows the action to work with +// move-only types like std::move_only_function in a type-safe manner. +// +// For example: +// +// // Assume we have some API that needs to accept a unique pointer to some +// // non-copyable object Foo. +// void AcceptUniquePointer(std::unique_ptr<Foo> foo); +// +// // We can define an action that provides a Foo to that API. Because It +// // has to give away its unique pointer, it must not be called more than +// // once, so its call operator is &&-qualified. +// struct ProvideFoo { +// std::unique_ptr<Foo> foo; +// +// void operator()() && { +// AcceptUniquePointer(std::move(Foo)); +// } +// }; +// +// // This action can be used with WillOnce. +// EXPECT_CALL(mock, Call) +// .WillOnce(ProvideFoo{std::make_unique<Foo>(...)}); +// +// // But a call to WillRepeatedly will fail to compile. This is correct, +// // since the action cannot correctly be used repeatedly. +// EXPECT_CALL(mock, Call) +// .WillRepeatedly(ProvideFoo{std::make_unique<Foo>(...)}); +// +// A less-contrived example would be an action that returns an arbitrary type, +// whose &&-qualified call operator is capable of dealing with move-only types. +template <typename Result, typename... Args> +class OnceAction<Result(Args...)> final { + private: + // True iff we can use the given callable type (or lvalue reference) directly + // via ActionAdaptor. + template <typename Callable> + using IsDirectlyCompatible = internal::conjunction< + // It must be possible to capture the callable in ActionAdaptor. + std::is_constructible<typename std::decay<Callable>::type, Callable>, + // The callable must be compatible with our signature. + internal::is_callable_r<Result, typename std::decay<Callable>::type, + Args...>>; + + // True iff we can use the given callable type via ActionAdaptor once we + // ignore incoming arguments. + template <typename Callable> + using IsCompatibleAfterIgnoringArguments = internal::conjunction< + // It must be possible to capture the callable in a lambda. + std::is_constructible<typename std::decay<Callable>::type, Callable>, + // The callable must be invocable with zero arguments, returning something + // convertible to Result. + internal::is_callable_r<Result, typename std::decay<Callable>::type>>; + + public: + // Construct from a callable that is directly compatible with our mocked + // signature: it accepts our function type's arguments and returns something + // convertible to our result type. + template <typename Callable, + typename std::enable_if< + internal::conjunction< + // Teach clang on macOS that we're not talking about a + // copy/move constructor here. Otherwise it gets confused + // when checking the is_constructible requirement of our + // traits above. + internal::negation<std::is_same< + OnceAction, typename std::decay<Callable>::type>>, + IsDirectlyCompatible<Callable>> // + ::value, + int>::type = 0> + OnceAction(Callable&& callable) // NOLINT + : action_(ActionAdaptor<typename std::decay<Callable>::type>( + {}, std::forward<Callable>(callable))) {} + + // As above, but for a callable that ignores the mocked function's arguments. + template <typename Callable, + typename std::enable_if< + internal::conjunction< + // Teach clang on macOS that we're not talking about a + // copy/move constructor here. Otherwise it gets confused + // when checking the is_constructible requirement of our + // traits above. + internal::negation<std::is_same< + OnceAction, typename std::decay<Callable>::type>>, + // Exclude callables for which the overload above works. + // We'd rather provide the arguments if possible. + internal::negation<IsDirectlyCompatible<Callable>>, + IsCompatibleAfterIgnoringArguments<Callable>>::value, + int>::type = 0> + OnceAction(Callable&& callable) // NOLINT + // Call the constructor above with a callable + // that ignores the input arguments. + : OnceAction(IgnoreIncomingArguments<typename std::decay<Callable>::type>{ + std::forward<Callable>(callable)}) {} + + // A fallback constructor for anything that is convertible to Action, for use + // with legacy actions that uses older styles like implementing + // ActionInterface or a conversion operator to Action. Modern code should + // implement a call operator with appropriate restrictions. + template <typename T, + typename std::enable_if< + internal::conjunction< + // Teach clang on macOS that we're not talking about a + // copy/move constructor here. Otherwise it gets confused + // when checking the is_constructible requirement of our + // traits above. + internal::negation< + std::is_same<OnceAction, typename std::decay<T>::type>>, + // Exclude the overloads above, which we want to take + // precedence. + internal::negation<IsDirectlyCompatible<T>>, + internal::negation<IsCompatibleAfterIgnoringArguments<T>>, + // It must be possible to turn the object into an action of + // the appropriate type. + std::is_convertible<T, Action<Result(Args...)>> // + >::value, + int>::type = 0> + OnceAction(T&& action) : action_(std::forward<T>(action)) {} // NOLINT + + // We are naturally copyable because we store only an Action, but semantically + // we should not be copyable. + OnceAction(const OnceAction&) = delete; + OnceAction& operator=(const OnceAction&) = delete; + OnceAction(OnceAction&&) = default; + + private: + // Allow TypedExpectation::WillOnce to use our type-unsafe API below. + friend class TypedExpectation<Result(Args...)>; + + // An adaptor that wraps a callable that is compatible with our signature and + // being invoked as an rvalue reference so that it can be used as an + // Action. This throws away type safety, but that's fine because this is only + // used by WillOnce, which we know calls at most once. + template <typename Callable> + class ActionAdaptor final { + public: + // A tag indicating that the (otherwise universal) constructor is accepting + // the callable itself, instead of e.g. stealing calls for the move + // constructor. + struct CallableTag final {}; + + template <typename F> + explicit ActionAdaptor(CallableTag, F&& callable) + : callable_(std::make_shared<Callable>(std::forward<F>(callable))) {} + + // Rather than explicitly returning Result, we return whatever the wrapped + // callable returns. This allows for compatibility with existing uses like + // the following, when the mocked function returns void: + // + // EXPECT_CALL(mock_fn_, Call) + // .WillOnce([&] { + // [...] + // return 0; + // }); + // + // This works with Action since such a callable can be turned into + // std::function<void()>. If we use an explicit return type of Result here + // then it *doesn't* work with OnceAction, because we'll get a "void + // function should not return a value" error. + // + // We need not worry about incompatible result types because the SFINAE on + // OnceAction already checks this for us. std::is_invocable_r_v itself makes + // the same allowance for void result types. + template <typename... ArgRefs> + internal::call_result_t<Callable, ArgRefs...> operator()( + ArgRefs&&... args) const { + return std::move(*callable_)(std::forward<ArgRefs>(args)...); + } + + private: + // We must put the callable on the heap so that we are copyable, which + // Action needs. + std::shared_ptr<Callable> callable_; + }; + + // An adaptor that makes a callable that accepts zero arguments callable with + // our mocked arguments. + template <typename Callable> + struct IgnoreIncomingArguments { + internal::call_result_t<Callable> operator()(Args&&...) { + return std::move(callable)(); + } + + Callable callable; + }; + + // Return an Action that calls the underlying callable in a type-safe manner. + // The action's Perform method must be called at most once. + // + // This is the transition from a type-safe API to a type-unsafe one, since + // "must be called at most once" is no longer reflecting in the type system. + Action<Result(Args...)> ReleaseAction() && { return std::move(action_); } + + Action<Result(Args...)> action_; +}; + // Helper struct to specialize ReturnAction to execute a move instead of a copy // on return. Useful for move-only types, but could be used on any type. template <typename T> diff --git a/googlemock/include/gmock/gmock-spec-builders.h b/googlemock/include/gmock/gmock-spec-builders.h index 8e4c5c6..917fa9a 100644 --- a/googlemock/include/gmock/gmock-spec-builders.h +++ b/googlemock/include/gmock/gmock-spec-builders.h @@ -992,14 +992,16 @@ class TypedExpectation : public ExpectationBase { return After(s1, s2, s3, s4).After(s5); } - // Implements the .WillOnce() clause. - TypedExpectation& WillOnce(const Action<F>& action) { + // Implements the .WillOnce() clause for copyable actions. + TypedExpectation& WillOnce(OnceAction<F> once_action) { ExpectSpecProperty(last_clause_ <= kWillOnce, ".WillOnce() cannot appear after " ".WillRepeatedly() or .RetiresOnSaturation()."); last_clause_ = kWillOnce; - untyped_actions_.push_back(new Action<F>(action)); + untyped_actions_.push_back( + new Action<F>(std::move(once_action).ReleaseAction())); + if (!cardinality_specified()) { set_cardinality(Exactly(static_cast<int>(untyped_actions_.size()))); } |