gmock-actions.h revision 13481
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29//
30// Author: wan@google.com (Zhanyong Wan)
31
32// Google Mock - a framework for writing C++ mock classes.
33//
34// This file implements some commonly used actions.
35
36#ifndef GMOCK_INCLUDE_GMOCK_GMOCK_ACTIONS_H_
37#define GMOCK_INCLUDE_GMOCK_GMOCK_ACTIONS_H_
38
39#ifndef _WIN32_WCE
40# include <errno.h>
41#endif
42
43#include <algorithm>
44#include <string>
45
46#include "gmock/internal/gmock-internal-utils.h"
47#include "gmock/internal/gmock-port.h"
48
49#if GTEST_HAS_STD_TYPE_TRAITS_  // Defined by gtest-port.h via gmock-port.h.
50#include <type_traits>
51#endif
52
53namespace testing {
54
55// To implement an action Foo, define:
56//   1. a class FooAction that implements the ActionInterface interface, and
57//   2. a factory function that creates an Action object from a
58//      const FooAction*.
59//
60// The two-level delegation design follows that of Matcher, providing
61// consistency for extension developers.  It also eases ownership
62// management as Action objects can now be copied like plain values.
63
64namespace internal {
65
66template <typename F1, typename F2>
67class ActionAdaptor;
68
69// BuiltInDefaultValueGetter<T, true>::Get() returns a
70// default-constructed T value.  BuiltInDefaultValueGetter<T,
71// false>::Get() crashes with an error.
72//
73// This primary template is used when kDefaultConstructible is true.
74template <typename T, bool kDefaultConstructible>
75struct BuiltInDefaultValueGetter {
76  static T Get() { return T(); }
77};
78template <typename T>
79struct BuiltInDefaultValueGetter<T, false> {
80  static T Get() {
81    Assert(false, __FILE__, __LINE__,
82           "Default action undefined for the function return type.");
83    return internal::Invalid<T>();
84    // The above statement will never be reached, but is required in
85    // order for this function to compile.
86  }
87};
88
89// BuiltInDefaultValue<T>::Get() returns the "built-in" default value
90// for type T, which is NULL when T is a raw pointer type, 0 when T is
91// a numeric type, false when T is bool, or "" when T is string or
92// std::string.  In addition, in C++11 and above, it turns a
93// default-constructed T value if T is default constructible.  For any
94// other type T, the built-in default T value is undefined, and the
95// function will abort the process.
96template <typename T>
97class BuiltInDefaultValue {
98 public:
99#if GTEST_HAS_STD_TYPE_TRAITS_
100  // This function returns true iff type T has a built-in default value.
101  static bool Exists() {
102    return ::std::is_default_constructible<T>::value;
103  }
104
105  static T Get() {
106    return BuiltInDefaultValueGetter<
107        T, ::std::is_default_constructible<T>::value>::Get();
108  }
109
110#else  // GTEST_HAS_STD_TYPE_TRAITS_
111  // This function returns true iff type T has a built-in default value.
112  static bool Exists() {
113    return false;
114  }
115
116  static T Get() {
117    return BuiltInDefaultValueGetter<T, false>::Get();
118  }
119
120#endif  // GTEST_HAS_STD_TYPE_TRAITS_
121};
122
123// This partial specialization says that we use the same built-in
124// default value for T and const T.
125template <typename T>
126class BuiltInDefaultValue<const T> {
127 public:
128  static bool Exists() { return BuiltInDefaultValue<T>::Exists(); }
129  static T Get() { return BuiltInDefaultValue<T>::Get(); }
130};
131
132// This partial specialization defines the default values for pointer
133// types.
134template <typename T>
135class BuiltInDefaultValue<T*> {
136 public:
137  static bool Exists() { return true; }
138  static T* Get() { return NULL; }
139};
140
141// The following specializations define the default values for
142// specific types we care about.
143#define GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(type, value) \
144  template <> \
145  class BuiltInDefaultValue<type> { \
146   public: \
147    static bool Exists() { return true; } \
148    static type Get() { return value; } \
149  }
150
151GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(void, );  // NOLINT
152#if GTEST_HAS_GLOBAL_STRING
153GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(::string, "");
154#endif  // GTEST_HAS_GLOBAL_STRING
155GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(::std::string, "");
156GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(bool, false);
157GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned char, '\0');
158GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed char, '\0');
159GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(char, '\0');
160
161// There's no need for a default action for signed wchar_t, as that
162// type is the same as wchar_t for gcc, and invalid for MSVC.
163//
164// There's also no need for a default action for unsigned wchar_t, as
165// that type is the same as unsigned int for gcc, and invalid for
166// MSVC.
167#if GMOCK_WCHAR_T_IS_NATIVE_
168GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(wchar_t, 0U);  // NOLINT
169#endif
170
171GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned short, 0U);  // NOLINT
172GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed short, 0);     // NOLINT
173GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned int, 0U);
174GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed int, 0);
175GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned long, 0UL);  // NOLINT
176GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed long, 0L);     // NOLINT
177GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(UInt64, 0);
178GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(Int64, 0);
179GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(float, 0);
180GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(double, 0);
181
182#undef GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_
183
184}  // namespace internal
185
186// When an unexpected function call is encountered, Google Mock will
187// let it return a default value if the user has specified one for its
188// return type, or if the return type has a built-in default value;
189// otherwise Google Mock won't know what value to return and will have
190// to abort the process.
191//
192// The DefaultValue<T> class allows a user to specify the
193// default value for a type T that is both copyable and publicly
194// destructible (i.e. anything that can be used as a function return
195// type).  The usage is:
196//
197//   // Sets the default value for type T to be foo.
198//   DefaultValue<T>::Set(foo);
199template <typename T>
200class DefaultValue {
201 public:
202  // Sets the default value for type T; requires T to be
203  // copy-constructable and have a public destructor.
204  static void Set(T x) {
205    delete producer_;
206    producer_ = new FixedValueProducer(x);
207  }
208
209  // Provides a factory function to be called to generate the default value.
210  // This method can be used even if T is only move-constructible, but it is not
211  // limited to that case.
212  typedef T (*FactoryFunction)();
213  static void SetFactory(FactoryFunction factory) {
214    delete producer_;
215    producer_ = new FactoryValueProducer(factory);
216  }
217
218  // Unsets the default value for type T.
219  static void Clear() {
220    delete producer_;
221    producer_ = NULL;
222  }
223
224  // Returns true iff the user has set the default value for type T.
225  static bool IsSet() { return producer_ != NULL; }
226
227  // Returns true if T has a default return value set by the user or there
228  // exists a built-in default value.
229  static bool Exists() {
230    return IsSet() || internal::BuiltInDefaultValue<T>::Exists();
231  }
232
233  // Returns the default value for type T if the user has set one;
234  // otherwise returns the built-in default value. Requires that Exists()
235  // is true, which ensures that the return value is well-defined.
236  static T Get() {
237    return producer_ == NULL ?
238        internal::BuiltInDefaultValue<T>::Get() : producer_->Produce();
239  }
240
241 private:
242  class ValueProducer {
243   public:
244    virtual ~ValueProducer() {}
245    virtual T Produce() = 0;
246  };
247
248  class FixedValueProducer : public ValueProducer {
249   public:
250    explicit FixedValueProducer(T value) : value_(value) {}
251    virtual T Produce() { return value_; }
252
253   private:
254    const T value_;
255    GTEST_DISALLOW_COPY_AND_ASSIGN_(FixedValueProducer);
256  };
257
258  class FactoryValueProducer : public ValueProducer {
259   public:
260    explicit FactoryValueProducer(FactoryFunction factory)
261        : factory_(factory) {}
262    virtual T Produce() { return factory_(); }
263
264   private:
265    const FactoryFunction factory_;
266    GTEST_DISALLOW_COPY_AND_ASSIGN_(FactoryValueProducer);
267  };
268
269  static ValueProducer* producer_;
270};
271
272// This partial specialization allows a user to set default values for
273// reference types.
274template <typename T>
275class DefaultValue<T&> {
276 public:
277  // Sets the default value for type T&.
278  static void Set(T& x) {  // NOLINT
279    address_ = &x;
280  }
281
282  // Unsets the default value for type T&.
283  static void Clear() {
284    address_ = NULL;
285  }
286
287  // Returns true iff the user has set the default value for type T&.
288  static bool IsSet() { return address_ != NULL; }
289
290  // Returns true if T has a default return value set by the user or there
291  // exists a built-in default value.
292  static bool Exists() {
293    return IsSet() || internal::BuiltInDefaultValue<T&>::Exists();
294  }
295
296  // Returns the default value for type T& if the user has set one;
297  // otherwise returns the built-in default value if there is one;
298  // otherwise aborts the process.
299  static T& Get() {
300    return address_ == NULL ?
301        internal::BuiltInDefaultValue<T&>::Get() : *address_;
302  }
303
304 private:
305  static T* address_;
306};
307
308// This specialization allows DefaultValue<void>::Get() to
309// compile.
310template <>
311class DefaultValue<void> {
312 public:
313  static bool Exists() { return true; }
314  static void Get() {}
315};
316
317// Points to the user-set default value for type T.
318template <typename T>
319typename DefaultValue<T>::ValueProducer* DefaultValue<T>::producer_ = NULL;
320
321// Points to the user-set default value for type T&.
322template <typename T>
323T* DefaultValue<T&>::address_ = NULL;
324
325// Implement this interface to define an action for function type F.
326template <typename F>
327class ActionInterface {
328 public:
329  typedef typename internal::Function<F>::Result Result;
330  typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
331
332  ActionInterface() {}
333  virtual ~ActionInterface() {}
334
335  // Performs the action.  This method is not const, as in general an
336  // action can have side effects and be stateful.  For example, a
337  // get-the-next-element-from-the-collection action will need to
338  // remember the current element.
339  virtual Result Perform(const ArgumentTuple& args) = 0;
340
341 private:
342  GTEST_DISALLOW_COPY_AND_ASSIGN_(ActionInterface);
343};
344
345// An Action<F> is a copyable and IMMUTABLE (except by assignment)
346// object that represents an action to be taken when a mock function
347// of type F is called.  The implementation of Action<T> is just a
348// linked_ptr to const ActionInterface<T>, so copying is fairly cheap.
349// Don't inherit from Action!
350//
351// You can view an object implementing ActionInterface<F> as a
352// concrete action (including its current state), and an Action<F>
353// object as a handle to it.
354template <typename F>
355class Action {
356 public:
357  typedef typename internal::Function<F>::Result Result;
358  typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
359
360  // Constructs a null Action.  Needed for storing Action objects in
361  // STL containers.
362  Action() : impl_(NULL) {}
363
364  // Constructs an Action from its implementation.  A NULL impl is
365  // used to represent the "do-default" action.
366  explicit Action(ActionInterface<F>* impl) : impl_(impl) {}
367
368  // Copy constructor.
369  Action(const Action& action) : impl_(action.impl_) {}
370
371  // This constructor allows us to turn an Action<Func> object into an
372  // Action<F>, as long as F's arguments can be implicitly converted
373  // to Func's and Func's return type can be implicitly converted to
374  // F's.
375  template <typename Func>
376  explicit Action(const Action<Func>& action);
377
378  // Returns true iff this is the DoDefault() action.
379  bool IsDoDefault() const { return impl_.get() == NULL; }
380
381  // Performs the action.  Note that this method is const even though
382  // the corresponding method in ActionInterface is not.  The reason
383  // is that a const Action<F> means that it cannot be re-bound to
384  // another concrete action, not that the concrete action it binds to
385  // cannot change state.  (Think of the difference between a const
386  // pointer and a pointer to const.)
387  Result Perform(const ArgumentTuple& args) const {
388    internal::Assert(
389        !IsDoDefault(), __FILE__, __LINE__,
390        "You are using DoDefault() inside a composite action like "
391        "DoAll() or WithArgs().  This is not supported for technical "
392        "reasons.  Please instead spell out the default action, or "
393        "assign the default action to an Action variable and use "
394        "the variable in various places.");
395    return impl_->Perform(args);
396  }
397
398 private:
399  template <typename F1, typename F2>
400  friend class internal::ActionAdaptor;
401
402  internal::linked_ptr<ActionInterface<F> > impl_;
403};
404
405// The PolymorphicAction class template makes it easy to implement a
406// polymorphic action (i.e. an action that can be used in mock
407// functions of than one type, e.g. Return()).
408//
409// To define a polymorphic action, a user first provides a COPYABLE
410// implementation class that has a Perform() method template:
411//
412//   class FooAction {
413//    public:
414//     template <typename Result, typename ArgumentTuple>
415//     Result Perform(const ArgumentTuple& args) const {
416//       // Processes the arguments and returns a result, using
417//       // tr1::get<N>(args) to get the N-th (0-based) argument in the tuple.
418//     }
419//     ...
420//   };
421//
422// Then the user creates the polymorphic action using
423// MakePolymorphicAction(object) where object has type FooAction.  See
424// the definition of Return(void) and SetArgumentPointee<N>(value) for
425// complete examples.
426template <typename Impl>
427class PolymorphicAction {
428 public:
429  explicit PolymorphicAction(const Impl& impl) : impl_(impl) {}
430
431  template <typename F>
432  operator Action<F>() const {
433    return Action<F>(new MonomorphicImpl<F>(impl_));
434  }
435
436 private:
437  template <typename F>
438  class MonomorphicImpl : public ActionInterface<F> {
439   public:
440    typedef typename internal::Function<F>::Result Result;
441    typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
442
443    explicit MonomorphicImpl(const Impl& impl) : impl_(impl) {}
444
445    virtual Result Perform(const ArgumentTuple& args) {
446      return impl_.template Perform<Result>(args);
447    }
448
449   private:
450    Impl impl_;
451
452    GTEST_DISALLOW_ASSIGN_(MonomorphicImpl);
453  };
454
455  Impl impl_;
456
457  GTEST_DISALLOW_ASSIGN_(PolymorphicAction);
458};
459
460// Creates an Action from its implementation and returns it.  The
461// created Action object owns the implementation.
462template <typename F>
463Action<F> MakeAction(ActionInterface<F>* impl) {
464  return Action<F>(impl);
465}
466
467// Creates a polymorphic action from its implementation.  This is
468// easier to use than the PolymorphicAction<Impl> constructor as it
469// doesn't require you to explicitly write the template argument, e.g.
470//
471//   MakePolymorphicAction(foo);
472// vs
473//   PolymorphicAction<TypeOfFoo>(foo);
474template <typename Impl>
475inline PolymorphicAction<Impl> MakePolymorphicAction(const Impl& impl) {
476  return PolymorphicAction<Impl>(impl);
477}
478
479namespace internal {
480
481// Allows an Action<F2> object to pose as an Action<F1>, as long as F2
482// and F1 are compatible.
483template <typename F1, typename F2>
484class ActionAdaptor : public ActionInterface<F1> {
485 public:
486  typedef typename internal::Function<F1>::Result Result;
487  typedef typename internal::Function<F1>::ArgumentTuple ArgumentTuple;
488
489  explicit ActionAdaptor(const Action<F2>& from) : impl_(from.impl_) {}
490
491  virtual Result Perform(const ArgumentTuple& args) {
492    return impl_->Perform(args);
493  }
494
495 private:
496  const internal::linked_ptr<ActionInterface<F2> > impl_;
497
498  GTEST_DISALLOW_ASSIGN_(ActionAdaptor);
499};
500
501// Helper struct to specialize ReturnAction to execute a move instead of a copy
502// on return. Useful for move-only types, but could be used on any type.
503template <typename T>
504struct ByMoveWrapper {
505  explicit ByMoveWrapper(T value) : payload(internal::move(value)) {}
506  T payload;
507};
508
509// Implements the polymorphic Return(x) action, which can be used in
510// any function that returns the type of x, regardless of the argument
511// types.
512//
513// Note: The value passed into Return must be converted into
514// Function<F>::Result when this action is cast to Action<F> rather than
515// when that action is performed. This is important in scenarios like
516//
517// MOCK_METHOD1(Method, T(U));
518// ...
519// {
520//   Foo foo;
521//   X x(&foo);
522//   EXPECT_CALL(mock, Method(_)).WillOnce(Return(x));
523// }
524//
525// In the example above the variable x holds reference to foo which leaves
526// scope and gets destroyed.  If copying X just copies a reference to foo,
527// that copy will be left with a hanging reference.  If conversion to T
528// makes a copy of foo, the above code is safe. To support that scenario, we
529// need to make sure that the type conversion happens inside the EXPECT_CALL
530// statement, and conversion of the result of Return to Action<T(U)> is a
531// good place for that.
532//
533template <typename R>
534class ReturnAction {
535 public:
536  // Constructs a ReturnAction object from the value to be returned.
537  // 'value' is passed by value instead of by const reference in order
538  // to allow Return("string literal") to compile.
539  explicit ReturnAction(R value) : value_(new R(internal::move(value))) {}
540
541  // This template type conversion operator allows Return(x) to be
542  // used in ANY function that returns x's type.
543  template <typename F>
544  operator Action<F>() const {
545    // Assert statement belongs here because this is the best place to verify
546    // conditions on F. It produces the clearest error messages
547    // in most compilers.
548    // Impl really belongs in this scope as a local class but can't
549    // because MSVC produces duplicate symbols in different translation units
550    // in this case. Until MS fixes that bug we put Impl into the class scope
551    // and put the typedef both here (for use in assert statement) and
552    // in the Impl class. But both definitions must be the same.
553    typedef typename Function<F>::Result Result;
554    GTEST_COMPILE_ASSERT_(
555        !is_reference<Result>::value,
556        use_ReturnRef_instead_of_Return_to_return_a_reference);
557    return Action<F>(new Impl<R, F>(value_));
558  }
559
560 private:
561  // Implements the Return(x) action for a particular function type F.
562  template <typename R_, typename F>
563  class Impl : public ActionInterface<F> {
564   public:
565    typedef typename Function<F>::Result Result;
566    typedef typename Function<F>::ArgumentTuple ArgumentTuple;
567
568    // The implicit cast is necessary when Result has more than one
569    // single-argument constructor (e.g. Result is std::vector<int>) and R
570    // has a type conversion operator template.  In that case, value_(value)
571    // won't compile as the compiler doesn't known which constructor of
572    // Result to call.  ImplicitCast_ forces the compiler to convert R to
573    // Result without considering explicit constructors, thus resolving the
574    // ambiguity. value_ is then initialized using its copy constructor.
575    explicit Impl(const linked_ptr<R>& value)
576        : value_before_cast_(*value),
577          value_(ImplicitCast_<Result>(value_before_cast_)) {}
578
579    virtual Result Perform(const ArgumentTuple&) { return value_; }
580
581   private:
582    GTEST_COMPILE_ASSERT_(!is_reference<Result>::value,
583                          Result_cannot_be_a_reference_type);
584    // We save the value before casting just in case it is being cast to a
585    // wrapper type.
586    R value_before_cast_;
587    Result value_;
588
589    GTEST_DISALLOW_COPY_AND_ASSIGN_(Impl);
590  };
591
592  // Partially specialize for ByMoveWrapper. This version of ReturnAction will
593  // move its contents instead.
594  template <typename R_, typename F>
595  class Impl<ByMoveWrapper<R_>, F> : public ActionInterface<F> {
596   public:
597    typedef typename Function<F>::Result Result;
598    typedef typename Function<F>::ArgumentTuple ArgumentTuple;
599
600    explicit Impl(const linked_ptr<R>& wrapper)
601        : performed_(false), wrapper_(wrapper) {}
602
603    virtual Result Perform(const ArgumentTuple&) {
604      GTEST_CHECK_(!performed_)
605          << "A ByMove() action should only be performed once.";
606      performed_ = true;
607      return internal::move(wrapper_->payload);
608    }
609
610   private:
611    bool performed_;
612    const linked_ptr<R> wrapper_;
613
614    GTEST_DISALLOW_ASSIGN_(Impl);
615  };
616
617  const linked_ptr<R> value_;
618
619  GTEST_DISALLOW_ASSIGN_(ReturnAction);
620};
621
622// Implements the ReturnNull() action.
623class ReturnNullAction {
624 public:
625  // Allows ReturnNull() to be used in any pointer-returning function. In C++11
626  // this is enforced by returning nullptr, and in non-C++11 by asserting a
627  // pointer type on compile time.
628  template <typename Result, typename ArgumentTuple>
629  static Result Perform(const ArgumentTuple&) {
630#if GTEST_LANG_CXX11
631    return nullptr;
632#else
633    GTEST_COMPILE_ASSERT_(internal::is_pointer<Result>::value,
634                          ReturnNull_can_be_used_to_return_a_pointer_only);
635    return NULL;
636#endif  // GTEST_LANG_CXX11
637  }
638};
639
640// Implements the Return() action.
641class ReturnVoidAction {
642 public:
643  // Allows Return() to be used in any void-returning function.
644  template <typename Result, typename ArgumentTuple>
645  static void Perform(const ArgumentTuple&) {
646    CompileAssertTypesEqual<void, Result>();
647  }
648};
649
650// Implements the polymorphic ReturnRef(x) action, which can be used
651// in any function that returns a reference to the type of x,
652// regardless of the argument types.
653template <typename T>
654class ReturnRefAction {
655 public:
656  // Constructs a ReturnRefAction object from the reference to be returned.
657  explicit ReturnRefAction(T& ref) : ref_(ref) {}  // NOLINT
658
659  // This template type conversion operator allows ReturnRef(x) to be
660  // used in ANY function that returns a reference to x's type.
661  template <typename F>
662  operator Action<F>() const {
663    typedef typename Function<F>::Result Result;
664    // Asserts that the function return type is a reference.  This
665    // catches the user error of using ReturnRef(x) when Return(x)
666    // should be used, and generates some helpful error message.
667    GTEST_COMPILE_ASSERT_(internal::is_reference<Result>::value,
668                          use_Return_instead_of_ReturnRef_to_return_a_value);
669    return Action<F>(new Impl<F>(ref_));
670  }
671
672 private:
673  // Implements the ReturnRef(x) action for a particular function type F.
674  template <typename F>
675  class Impl : public ActionInterface<F> {
676   public:
677    typedef typename Function<F>::Result Result;
678    typedef typename Function<F>::ArgumentTuple ArgumentTuple;
679
680    explicit Impl(T& ref) : ref_(ref) {}  // NOLINT
681
682    virtual Result Perform(const ArgumentTuple&) {
683      return ref_;
684    }
685
686   private:
687    T& ref_;
688
689    GTEST_DISALLOW_ASSIGN_(Impl);
690  };
691
692  T& ref_;
693
694  GTEST_DISALLOW_ASSIGN_(ReturnRefAction);
695};
696
697// Implements the polymorphic ReturnRefOfCopy(x) action, which can be
698// used in any function that returns a reference to the type of x,
699// regardless of the argument types.
700template <typename T>
701class ReturnRefOfCopyAction {
702 public:
703  // Constructs a ReturnRefOfCopyAction object from the reference to
704  // be returned.
705  explicit ReturnRefOfCopyAction(const T& value) : value_(value) {}  // NOLINT
706
707  // This template type conversion operator allows ReturnRefOfCopy(x) to be
708  // used in ANY function that returns a reference to x's type.
709  template <typename F>
710  operator Action<F>() const {
711    typedef typename Function<F>::Result Result;
712    // Asserts that the function return type is a reference.  This
713    // catches the user error of using ReturnRefOfCopy(x) when Return(x)
714    // should be used, and generates some helpful error message.
715    GTEST_COMPILE_ASSERT_(
716        internal::is_reference<Result>::value,
717        use_Return_instead_of_ReturnRefOfCopy_to_return_a_value);
718    return Action<F>(new Impl<F>(value_));
719  }
720
721 private:
722  // Implements the ReturnRefOfCopy(x) action for a particular function type F.
723  template <typename F>
724  class Impl : public ActionInterface<F> {
725   public:
726    typedef typename Function<F>::Result Result;
727    typedef typename Function<F>::ArgumentTuple ArgumentTuple;
728
729    explicit Impl(const T& value) : value_(value) {}  // NOLINT
730
731    virtual Result Perform(const ArgumentTuple&) {
732      return value_;
733    }
734
735   private:
736    T value_;
737
738    GTEST_DISALLOW_ASSIGN_(Impl);
739  };
740
741  const T value_;
742
743  GTEST_DISALLOW_ASSIGN_(ReturnRefOfCopyAction);
744};
745
746// Implements the polymorphic DoDefault() action.
747class DoDefaultAction {
748 public:
749  // This template type conversion operator allows DoDefault() to be
750  // used in any function.
751  template <typename F>
752  operator Action<F>() const { return Action<F>(NULL); }
753};
754
755// Implements the Assign action to set a given pointer referent to a
756// particular value.
757template <typename T1, typename T2>
758class AssignAction {
759 public:
760  AssignAction(T1* ptr, T2 value) : ptr_(ptr), value_(value) {}
761
762  template <typename Result, typename ArgumentTuple>
763  void Perform(const ArgumentTuple& /* args */) const {
764    *ptr_ = value_;
765  }
766
767 private:
768  T1* const ptr_;
769  const T2 value_;
770
771  GTEST_DISALLOW_ASSIGN_(AssignAction);
772};
773
774#if !GTEST_OS_WINDOWS_MOBILE
775
776// Implements the SetErrnoAndReturn action to simulate return from
777// various system calls and libc functions.
778template <typename T>
779class SetErrnoAndReturnAction {
780 public:
781  SetErrnoAndReturnAction(int errno_value, T result)
782      : errno_(errno_value),
783        result_(result) {}
784  template <typename Result, typename ArgumentTuple>
785  Result Perform(const ArgumentTuple& /* args */) const {
786    errno = errno_;
787    return result_;
788  }
789
790 private:
791  const int errno_;
792  const T result_;
793
794  GTEST_DISALLOW_ASSIGN_(SetErrnoAndReturnAction);
795};
796
797#endif  // !GTEST_OS_WINDOWS_MOBILE
798
799// Implements the SetArgumentPointee<N>(x) action for any function
800// whose N-th argument (0-based) is a pointer to x's type.  The
801// template parameter kIsProto is true iff type A is ProtocolMessage,
802// proto2::Message, or a sub-class of those.
803template <size_t N, typename A, bool kIsProto>
804class SetArgumentPointeeAction {
805 public:
806  // Constructs an action that sets the variable pointed to by the
807  // N-th function argument to 'value'.
808  explicit SetArgumentPointeeAction(const A& value) : value_(value) {}
809
810  template <typename Result, typename ArgumentTuple>
811  void Perform(const ArgumentTuple& args) const {
812    CompileAssertTypesEqual<void, Result>();
813    *::testing::get<N>(args) = value_;
814  }
815
816 private:
817  const A value_;
818
819  GTEST_DISALLOW_ASSIGN_(SetArgumentPointeeAction);
820};
821
822template <size_t N, typename Proto>
823class SetArgumentPointeeAction<N, Proto, true> {
824 public:
825  // Constructs an action that sets the variable pointed to by the
826  // N-th function argument to 'proto'.  Both ProtocolMessage and
827  // proto2::Message have the CopyFrom() method, so the same
828  // implementation works for both.
829  explicit SetArgumentPointeeAction(const Proto& proto) : proto_(new Proto) {
830    proto_->CopyFrom(proto);
831  }
832
833  template <typename Result, typename ArgumentTuple>
834  void Perform(const ArgumentTuple& args) const {
835    CompileAssertTypesEqual<void, Result>();
836    ::testing::get<N>(args)->CopyFrom(*proto_);
837  }
838
839 private:
840  const internal::linked_ptr<Proto> proto_;
841
842  GTEST_DISALLOW_ASSIGN_(SetArgumentPointeeAction);
843};
844
845// Implements the InvokeWithoutArgs(f) action.  The template argument
846// FunctionImpl is the implementation type of f, which can be either a
847// function pointer or a functor.  InvokeWithoutArgs(f) can be used as an
848// Action<F> as long as f's type is compatible with F (i.e. f can be
849// assigned to a tr1::function<F>).
850template <typename FunctionImpl>
851class InvokeWithoutArgsAction {
852 public:
853  // The c'tor makes a copy of function_impl (either a function
854  // pointer or a functor).
855  explicit InvokeWithoutArgsAction(FunctionImpl function_impl)
856      : function_impl_(function_impl) {}
857
858  // Allows InvokeWithoutArgs(f) to be used as any action whose type is
859  // compatible with f.
860  template <typename Result, typename ArgumentTuple>
861  Result Perform(const ArgumentTuple&) { return function_impl_(); }
862
863 private:
864  FunctionImpl function_impl_;
865
866  GTEST_DISALLOW_ASSIGN_(InvokeWithoutArgsAction);
867};
868
869// Implements the InvokeWithoutArgs(object_ptr, &Class::Method) action.
870template <class Class, typename MethodPtr>
871class InvokeMethodWithoutArgsAction {
872 public:
873  InvokeMethodWithoutArgsAction(Class* obj_ptr, MethodPtr method_ptr)
874      : obj_ptr_(obj_ptr), method_ptr_(method_ptr) {}
875
876  template <typename Result, typename ArgumentTuple>
877  Result Perform(const ArgumentTuple&) const {
878    return (obj_ptr_->*method_ptr_)();
879  }
880
881 private:
882  Class* const obj_ptr_;
883  const MethodPtr method_ptr_;
884
885  GTEST_DISALLOW_ASSIGN_(InvokeMethodWithoutArgsAction);
886};
887
888// Implements the IgnoreResult(action) action.
889template <typename A>
890class IgnoreResultAction {
891 public:
892  explicit IgnoreResultAction(const A& action) : action_(action) {}
893
894  template <typename F>
895  operator Action<F>() const {
896    // Assert statement belongs here because this is the best place to verify
897    // conditions on F. It produces the clearest error messages
898    // in most compilers.
899    // Impl really belongs in this scope as a local class but can't
900    // because MSVC produces duplicate symbols in different translation units
901    // in this case. Until MS fixes that bug we put Impl into the class scope
902    // and put the typedef both here (for use in assert statement) and
903    // in the Impl class. But both definitions must be the same.
904    typedef typename internal::Function<F>::Result Result;
905
906    // Asserts at compile time that F returns void.
907    CompileAssertTypesEqual<void, Result>();
908
909    return Action<F>(new Impl<F>(action_));
910  }
911
912 private:
913  template <typename F>
914  class Impl : public ActionInterface<F> {
915   public:
916    typedef typename internal::Function<F>::Result Result;
917    typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
918
919    explicit Impl(const A& action) : action_(action) {}
920
921    virtual void Perform(const ArgumentTuple& args) {
922      // Performs the action and ignores its result.
923      action_.Perform(args);
924    }
925
926   private:
927    // Type OriginalFunction is the same as F except that its return
928    // type is IgnoredValue.
929    typedef typename internal::Function<F>::MakeResultIgnoredValue
930        OriginalFunction;
931
932    const Action<OriginalFunction> action_;
933
934    GTEST_DISALLOW_ASSIGN_(Impl);
935  };
936
937  const A action_;
938
939  GTEST_DISALLOW_ASSIGN_(IgnoreResultAction);
940};
941
942// A ReferenceWrapper<T> object represents a reference to type T,
943// which can be either const or not.  It can be explicitly converted
944// from, and implicitly converted to, a T&.  Unlike a reference,
945// ReferenceWrapper<T> can be copied and can survive template type
946// inference.  This is used to support by-reference arguments in the
947// InvokeArgument<N>(...) action.  The idea was from "reference
948// wrappers" in tr1, which we don't have in our source tree yet.
949template <typename T>
950class ReferenceWrapper {
951 public:
952  // Constructs a ReferenceWrapper<T> object from a T&.
953  explicit ReferenceWrapper(T& l_value) : pointer_(&l_value) {}  // NOLINT
954
955  // Allows a ReferenceWrapper<T> object to be implicitly converted to
956  // a T&.
957  operator T&() const { return *pointer_; }
958 private:
959  T* pointer_;
960};
961
962// Allows the expression ByRef(x) to be printed as a reference to x.
963template <typename T>
964void PrintTo(const ReferenceWrapper<T>& ref, ::std::ostream* os) {
965  T& value = ref;
966  UniversalPrinter<T&>::Print(value, os);
967}
968
969// Does two actions sequentially.  Used for implementing the DoAll(a1,
970// a2, ...) action.
971template <typename Action1, typename Action2>
972class DoBothAction {
973 public:
974  DoBothAction(Action1 action1, Action2 action2)
975      : action1_(action1), action2_(action2) {}
976
977  // This template type conversion operator allows DoAll(a1, ..., a_n)
978  // to be used in ANY function of compatible type.
979  template <typename F>
980  operator Action<F>() const {
981    return Action<F>(new Impl<F>(action1_, action2_));
982  }
983
984 private:
985  // Implements the DoAll(...) action for a particular function type F.
986  template <typename F>
987  class Impl : public ActionInterface<F> {
988   public:
989    typedef typename Function<F>::Result Result;
990    typedef typename Function<F>::ArgumentTuple ArgumentTuple;
991    typedef typename Function<F>::MakeResultVoid VoidResult;
992
993    Impl(const Action<VoidResult>& action1, const Action<F>& action2)
994        : action1_(action1), action2_(action2) {}
995
996    virtual Result Perform(const ArgumentTuple& args) {
997      action1_.Perform(args);
998      return action2_.Perform(args);
999    }
1000
1001   private:
1002    const Action<VoidResult> action1_;
1003    const Action<F> action2_;
1004
1005    GTEST_DISALLOW_ASSIGN_(Impl);
1006  };
1007
1008  Action1 action1_;
1009  Action2 action2_;
1010
1011  GTEST_DISALLOW_ASSIGN_(DoBothAction);
1012};
1013
1014}  // namespace internal
1015
1016// An Unused object can be implicitly constructed from ANY value.
1017// This is handy when defining actions that ignore some or all of the
1018// mock function arguments.  For example, given
1019//
1020//   MOCK_METHOD3(Foo, double(const string& label, double x, double y));
1021//   MOCK_METHOD3(Bar, double(int index, double x, double y));
1022//
1023// instead of
1024//
1025//   double DistanceToOriginWithLabel(const string& label, double x, double y) {
1026//     return sqrt(x*x + y*y);
1027//   }
1028//   double DistanceToOriginWithIndex(int index, double x, double y) {
1029//     return sqrt(x*x + y*y);
1030//   }
1031//   ...
1032//   EXEPCT_CALL(mock, Foo("abc", _, _))
1033//       .WillOnce(Invoke(DistanceToOriginWithLabel));
1034//   EXEPCT_CALL(mock, Bar(5, _, _))
1035//       .WillOnce(Invoke(DistanceToOriginWithIndex));
1036//
1037// you could write
1038//
1039//   // We can declare any uninteresting argument as Unused.
1040//   double DistanceToOrigin(Unused, double x, double y) {
1041//     return sqrt(x*x + y*y);
1042//   }
1043//   ...
1044//   EXEPCT_CALL(mock, Foo("abc", _, _)).WillOnce(Invoke(DistanceToOrigin));
1045//   EXEPCT_CALL(mock, Bar(5, _, _)).WillOnce(Invoke(DistanceToOrigin));
1046typedef internal::IgnoredValue Unused;
1047
1048// This constructor allows us to turn an Action<From> object into an
1049// Action<To>, as long as To's arguments can be implicitly converted
1050// to From's and From's return type cann be implicitly converted to
1051// To's.
1052template <typename To>
1053template <typename From>
1054Action<To>::Action(const Action<From>& from)
1055    : impl_(new internal::ActionAdaptor<To, From>(from)) {}
1056
1057// Creates an action that returns 'value'.  'value' is passed by value
1058// instead of const reference - otherwise Return("string literal")
1059// will trigger a compiler error about using array as initializer.
1060template <typename R>
1061internal::ReturnAction<R> Return(R value) {
1062  return internal::ReturnAction<R>(internal::move(value));
1063}
1064
1065// Creates an action that returns NULL.
1066inline PolymorphicAction<internal::ReturnNullAction> ReturnNull() {
1067  return MakePolymorphicAction(internal::ReturnNullAction());
1068}
1069
1070// Creates an action that returns from a void function.
1071inline PolymorphicAction<internal::ReturnVoidAction> Return() {
1072  return MakePolymorphicAction(internal::ReturnVoidAction());
1073}
1074
1075// Creates an action that returns the reference to a variable.
1076template <typename R>
1077inline internal::ReturnRefAction<R> ReturnRef(R& x) {  // NOLINT
1078  return internal::ReturnRefAction<R>(x);
1079}
1080
1081// Creates an action that returns the reference to a copy of the
1082// argument.  The copy is created when the action is constructed and
1083// lives as long as the action.
1084template <typename R>
1085inline internal::ReturnRefOfCopyAction<R> ReturnRefOfCopy(const R& x) {
1086  return internal::ReturnRefOfCopyAction<R>(x);
1087}
1088
1089// Modifies the parent action (a Return() action) to perform a move of the
1090// argument instead of a copy.
1091// Return(ByMove()) actions can only be executed once and will assert this
1092// invariant.
1093template <typename R>
1094internal::ByMoveWrapper<R> ByMove(R x) {
1095  return internal::ByMoveWrapper<R>(internal::move(x));
1096}
1097
1098// Creates an action that does the default action for the give mock function.
1099inline internal::DoDefaultAction DoDefault() {
1100  return internal::DoDefaultAction();
1101}
1102
1103// Creates an action that sets the variable pointed by the N-th
1104// (0-based) function argument to 'value'.
1105template <size_t N, typename T>
1106PolymorphicAction<
1107  internal::SetArgumentPointeeAction<
1108    N, T, internal::IsAProtocolMessage<T>::value> >
1109SetArgPointee(const T& x) {
1110  return MakePolymorphicAction(internal::SetArgumentPointeeAction<
1111      N, T, internal::IsAProtocolMessage<T>::value>(x));
1112}
1113
1114#if !((GTEST_GCC_VER_ && GTEST_GCC_VER_ < 40000) || GTEST_OS_SYMBIAN)
1115// This overload allows SetArgPointee() to accept a string literal.
1116// GCC prior to the version 4.0 and Symbian C++ compiler cannot distinguish
1117// this overload from the templated version and emit a compile error.
1118template <size_t N>
1119PolymorphicAction<
1120  internal::SetArgumentPointeeAction<N, const char*, false> >
1121SetArgPointee(const char* p) {
1122  return MakePolymorphicAction(internal::SetArgumentPointeeAction<
1123      N, const char*, false>(p));
1124}
1125
1126template <size_t N>
1127PolymorphicAction<
1128  internal::SetArgumentPointeeAction<N, const wchar_t*, false> >
1129SetArgPointee(const wchar_t* p) {
1130  return MakePolymorphicAction(internal::SetArgumentPointeeAction<
1131      N, const wchar_t*, false>(p));
1132}
1133#endif
1134
1135// The following version is DEPRECATED.
1136template <size_t N, typename T>
1137PolymorphicAction<
1138  internal::SetArgumentPointeeAction<
1139    N, T, internal::IsAProtocolMessage<T>::value> >
1140SetArgumentPointee(const T& x) {
1141  return MakePolymorphicAction(internal::SetArgumentPointeeAction<
1142      N, T, internal::IsAProtocolMessage<T>::value>(x));
1143}
1144
1145// Creates an action that sets a pointer referent to a given value.
1146template <typename T1, typename T2>
1147PolymorphicAction<internal::AssignAction<T1, T2> > Assign(T1* ptr, T2 val) {
1148  return MakePolymorphicAction(internal::AssignAction<T1, T2>(ptr, val));
1149}
1150
1151#if !GTEST_OS_WINDOWS_MOBILE
1152
1153// Creates an action that sets errno and returns the appropriate error.
1154template <typename T>
1155PolymorphicAction<internal::SetErrnoAndReturnAction<T> >
1156SetErrnoAndReturn(int errval, T result) {
1157  return MakePolymorphicAction(
1158      internal::SetErrnoAndReturnAction<T>(errval, result));
1159}
1160
1161#endif  // !GTEST_OS_WINDOWS_MOBILE
1162
1163// Various overloads for InvokeWithoutArgs().
1164
1165// Creates an action that invokes 'function_impl' with no argument.
1166template <typename FunctionImpl>
1167PolymorphicAction<internal::InvokeWithoutArgsAction<FunctionImpl> >
1168InvokeWithoutArgs(FunctionImpl function_impl) {
1169  return MakePolymorphicAction(
1170      internal::InvokeWithoutArgsAction<FunctionImpl>(function_impl));
1171}
1172
1173// Creates an action that invokes the given method on the given object
1174// with no argument.
1175template <class Class, typename MethodPtr>
1176PolymorphicAction<internal::InvokeMethodWithoutArgsAction<Class, MethodPtr> >
1177InvokeWithoutArgs(Class* obj_ptr, MethodPtr method_ptr) {
1178  return MakePolymorphicAction(
1179      internal::InvokeMethodWithoutArgsAction<Class, MethodPtr>(
1180          obj_ptr, method_ptr));
1181}
1182
1183// Creates an action that performs an_action and throws away its
1184// result.  In other words, it changes the return type of an_action to
1185// void.  an_action MUST NOT return void, or the code won't compile.
1186template <typename A>
1187inline internal::IgnoreResultAction<A> IgnoreResult(const A& an_action) {
1188  return internal::IgnoreResultAction<A>(an_action);
1189}
1190
1191// Creates a reference wrapper for the given L-value.  If necessary,
1192// you can explicitly specify the type of the reference.  For example,
1193// suppose 'derived' is an object of type Derived, ByRef(derived)
1194// would wrap a Derived&.  If you want to wrap a const Base& instead,
1195// where Base is a base class of Derived, just write:
1196//
1197//   ByRef<const Base>(derived)
1198template <typename T>
1199inline internal::ReferenceWrapper<T> ByRef(T& l_value) {  // NOLINT
1200  return internal::ReferenceWrapper<T>(l_value);
1201}
1202
1203}  // namespace testing
1204
1205#endif  // GMOCK_INCLUDE_GMOCK_GMOCK_ACTIONS_H_
1206