text: // Copyright 2007, Google Inc.
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  //     * Redistributions of source code must retain the above copyright
  // notice, this list of conditions and the following disclaimer.
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  // in the documentation and/or other materials provided with the
  // distribution.
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  // contributors may be used to endorse or promote products derived from
  // this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  //
  // Author: wan@google.com (Zhanyong Wan)
  
  // Google Mock - a framework for writing C++ mock classes.
  //
  // This file implements some commonly used actions.
  
  #ifndef GMOCK_INCLUDE_GMOCK_GMOCK_ACTIONS_H_
  #define GMOCK_INCLUDE_GMOCK_GMOCK_ACTIONS_H_
  
  #include <algorithm>
  #include <string>
  
  #ifndef _WIN32_WCE
  #include <errno.h>
  #endif
  
  #include <gmock/gmock-printers.h>
  #include <gmock/internal/gmock-internal-utils.h>
  #include <gmock/internal/gmock-port.h>
  
  namespace testing {
  
  // To implement an action Foo, define:
  //   1. a class FooAction that implements the ActionInterface interface, and
  //   2. a factory function that creates an Action object from a
  //      const FooAction*.
  //
  // The two-level delegation design follows that of Matcher, providing
  // consistency for extension developers.  It also eases ownership
  // management as Action objects can now be copied like plain values.
  
  namespace internal {
  
  template <typename F>
  class MonomorphicDoDefaultActionImpl;
  
  template <typename F1, typename F2>
  class ActionAdaptor;
  
  // BuiltInDefaultValue<T>::Get() returns the "built-in" default
  // value for type T, which is NULL when T is a pointer type, 0 when T
  // is a numeric type, false when T is bool, or "" when T is string or
  // std::string.  For any other type T, this value is undefined and the
  // function will abort the process.
  template <typename T>
  class BuiltInDefaultValue {
   public:
    // This function returns true iff type T has a built-in default value.
    static bool Exists() { return false; }
    static T Get() {
      Assert(false, __FILE__, __LINE__,
             "Default action undefined for the function return type.");
      return internal::Invalid<T>();
      // The above statement will never be reached, but is required in
      // order for this function to compile.
    }
  };
  
  // This partial specialization says that we use the same built-in
  // default value for T and const T.
  template <typename T>
  class BuiltInDefaultValue<const T> {
   public:
    static bool Exists() { return BuiltInDefaultValue<T>::Exists(); }
    static T Get() { return BuiltInDefaultValue<T>::Get(); }
  };
  
  // This partial specialization defines the default values for pointer
  // types.
  template <typename T>
  class BuiltInDefaultValue<T*> {
   public:
    static bool Exists() { return true; }
    static T* Get() { return NULL; }
  };
  
  // The following specializations define the default values for
  // specific types we care about.
  #define GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(type, value) \
    template <> \
    class BuiltInDefaultValue<type> { \
     public: \
      static bool Exists() { return true; } \
      static type Get() { return value; } \
    }
  
  GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(void, );  // NOLINT
  #if GTEST_HAS_GLOBAL_STRING
  GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(::string, "");
  #endif  // GTEST_HAS_GLOBAL_STRING
  GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(::std::string, "");
  GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(bool, false);
  GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned char, '\0');
  GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed char, '\0');
  GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(char, '\0');
  
  // There's no need for a default action for signed wchar_t, as that
  // type is the same as wchar_t for gcc, and invalid for MSVC.
  //
  // There's also no need for a default action for unsigned wchar_t, as
  // that type is the same as unsigned int for gcc, and invalid for
  // MSVC.
  #if GMOCK_WCHAR_T_IS_NATIVE_
  GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(wchar_t, 0U);  // NOLINT
  #endif
  
  GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned short, 0U);  // NOLINT
  GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed short, 0);     // NOLINT
  GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned int, 0U);
  GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed int, 0);
  GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(unsigned long, 0UL);  // NOLINT
  GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(signed long, 0L);     // NOLINT
  GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(UInt64, 0);
  GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(Int64, 0);
  GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(float, 0);
  GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_(double, 0);
  
  #undef GMOCK_DEFINE_DEFAULT_ACTION_FOR_RETURN_TYPE_
  
  }  // namespace internal
  
  // When an unexpected function call is encountered, Google Mock will
  // let it return a default value if the user has specified one for its
  // return type, or if the return type has a built-in default value;
  // otherwise Google Mock won't know what value to return and will have
  // to abort the process.
  //
  // The DefaultValue<T> class allows a user to specify the
  // default value for a type T that is both copyable and publicly
  // destructible (i.e. anything that can be used as a function return
  // type).  The usage is:
  //
  //   // Sets the default value for type T to be foo.
  //   DefaultValue<T>::Set(foo);
  template <typename T>
  class DefaultValue {
   public:
    // Sets the default value for type T; requires T to be
    // copy-constructable and have a public destructor.
    static void Set(T x) {
      delete value_;
      value_ = new T(x);
    }
  
    // Unsets the default value for type T.
    static void Clear() {
      delete value_;
      value_ = NULL;
    }
  
    // Returns true iff the user has set the default value for type T.
    static bool IsSet() { return value_ != NULL; }
  
    // Returns true if T has a default return value set by the user or there
    // exists a built-in default value.
    static bool Exists() {
      return IsSet() || internal::BuiltInDefaultValue<T>::Exists();
    }
  
    // Returns the default value for type T if the user has set one;
    // otherwise returns the built-in default value if there is one;
    // otherwise aborts the process.
    static T Get() {
      return value_ == NULL ?
          internal::BuiltInDefaultValue<T>::Get() : *value_;
    }
   private:
    static const T* value_;
  };
  
  // This partial specialization allows a user to set default values for
  // reference types.
  template <typename T>
  class DefaultValue<T&> {
   public:
    // Sets the default value for type T&.
    static void Set(T& x) {  // NOLINT
      address_ = &x;
    }
  
    // Unsets the default value for type T&.
    static void Clear() {
      address_ = NULL;
    }
  
    // Returns true iff the user has set the default value for type T&.
    static bool IsSet() { return address_ != NULL; }
  
    // Returns true if T has a default return value set by the user or there
    // exists a built-in default value.
    static bool Exists() {
      return IsSet() || internal::BuiltInDefaultValue<T&>::Exists();
    }
  
    // Returns the default value for type T& if the user has set one;
    // otherwise returns the built-in default value if there is one;
    // otherwise aborts the process.
    static T& Get() {
      return address_ == NULL ?
          internal::BuiltInDefaultValue<T&>::Get() : *address_;
    }
   private:
    static T* address_;
  };
  
  // This specialization allows DefaultValue<void>::Get() to
  // compile.
  template <>
  class DefaultValue<void> {
   public:
    static bool Exists() { return true; }
    static void Get() {}
  };
  
  // Points to the user-set default value for type T.
  template <typename T>
  const T* DefaultValue<T>::value_ = NULL;
  
  // Points to the user-set default value for type T&.
  template <typename T>
  T* DefaultValue<T&>::address_ = NULL;
  
  // Implement this interface to define an action for function type F.
  template <typename F>
  class ActionInterface {
   public:
    typedef typename internal::Function<F>::Result Result;
    typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
  
    ActionInterface() : is_do_default_(false) {}
  
    virtual ~ActionInterface() {}
  
    // Performs the action.  This method is not const, as in general an
    // action can have side effects and be stateful.  For example, a
    // get-the-next-element-from-the-collection action will need to
    // remember the current element.
    virtual Result Perform(const ArgumentTuple& args) = 0;
  
    // Returns true iff this is the DoDefault() action.
    bool IsDoDefault() const { return is_do_default_; }
  
   private:
    template <typename Function>
    friend class internal::MonomorphicDoDefaultActionImpl;
  
    // This private constructor is reserved for implementing
    // DoDefault(), the default action for a given mock function.
    explicit ActionInterface(bool is_do_default)
        : is_do_default_(is_do_default) {}
  
    // True iff this action is DoDefault().
    const bool is_do_default_;
  
    GTEST_DISALLOW_COPY_AND_ASSIGN_(ActionInterface);
  };
  
  // An Action<F> is a copyable and IMMUTABLE (except by assignment)
  // object that represents an action to be taken when a mock function
  // of type F is called.  The implementation of Action<T> is just a
  // linked_ptr to const ActionInterface<T>, so copying is fairly cheap.
  // Don't inherit from Action!
  //
  // You can view an object implementing ActionInterface<F> as a
  // concrete action (including its current state), and an Action<F>
  // object as a handle to it.
  template <typename F>
  class Action {
   public:
    typedef typename internal::Function<F>::Result Result;
    typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
  
    // Constructs a null Action.  Needed for storing Action objects in
    // STL containers.
    Action() : impl_(NULL) {}
  
    // Constructs an Action from its implementation.
    explicit Action(ActionInterface<F>* impl) : impl_(impl) {}
  
    // Copy constructor.
    Action(const Action& action) : impl_(action.impl_) {}
  
    // This constructor allows us to turn an Action<Func> object into an
    // Action<F>, as long as F's arguments can be implicitly converted
    // to Func's and Func's return type can be implicitly converted to
    // F's.
    template <typename Func>
    explicit Action(const Action<Func>& action);
  
    // Returns true iff this is the DoDefault() action.
    bool IsDoDefault() const { return impl_->IsDoDefault(); }
  
    // Performs the action.  Note that this method is const even though
    // the corresponding method in ActionInterface is not.  The reason
    // is that a const Action<F> means that it cannot be re-bound to
    // another concrete action, not that the concrete action it binds to
    // cannot change state.  (Think of the difference between a const
    // pointer and a pointer to const.)
    Result Perform(const ArgumentTuple& args) const {
      return impl_->Perform(args);
    }
  
   private:
    template <typename F1, typename F2>
    friend class internal::ActionAdaptor;
  
    internal::linked_ptr<ActionInterface<F> > impl_;
  };
  
  // The PolymorphicAction class template makes it easy to implement a
  // polymorphic action (i.e. an action that can be used in mock
  // functions of than one type, e.g. Return()).
  //
  // To define a polymorphic action, a user first provides a COPYABLE
  // implementation class that has a Perform() method template:
  //
  //   class FooAction {
  //    public:
  //     template <typename Result, typename ArgumentTuple>
  //     Result Perform(const ArgumentTuple& args) const {
  //       // Processes the arguments and returns a result, using
  //       // tr1::get<N>(args) to get the N-th (0-based) argument in the tuple.
  //     }
  //     ...
  //   };
  //
  // Then the user creates the polymorphic action using
  // MakePolymorphicAction(object) where object has type FooAction.  See
  // the definition of Return(void) and SetArgumentPointee<N>(value) for
  // complete examples.
  template <typename Impl>
  class PolymorphicAction {
   public:
    explicit PolymorphicAction(const Impl& impl) : impl_(impl) {}
  
    template <typename F>
    operator Action<F>() const {
      return Action<F>(new MonomorphicImpl<F>(impl_));
    }
  
   private:
    template <typename F>
    class MonomorphicImpl : public ActionInterface<F> {
     public:
      typedef typename internal::Function<F>::Result Result;
      typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
  
      explicit MonomorphicImpl(const Impl& impl) : impl_(impl) {}
  
      virtual Result Perform(const ArgumentTuple& args) {
        return impl_.template Perform<Result>(args);
      }
  
     private:
      Impl impl_;
  
      GTEST_DISALLOW_ASSIGN_(MonomorphicImpl);
    };
  
    Impl impl_;
  
    GTEST_DISALLOW_ASSIGN_(PolymorphicAction);
  };
  
  // Creates an Action from its implementation and returns it.  The
  // created Action object owns the implementation.
  template <typename F>
  Action<F> MakeAction(ActionInterface<F>* impl) {
    return Action<F>(impl);
  }
  
  // Creates a polymorphic action from its implementation.  This is
  // easier to use than the PolymorphicAction<Impl> constructor as it
  // doesn't require you to explicitly write the template argument, e.g.
  //
  //   MakePolymorphicAction(foo);
  // vs
  //   PolymorphicAction<TypeOfFoo>(foo);
  template <typename Impl>
  inline PolymorphicAction<Impl> MakePolymorphicAction(const Impl& impl) {
    return PolymorphicAction<Impl>(impl);
  }
  
  namespace internal {
  
  // Allows an Action<F2> object to pose as an Action<F1>, as long as F2
  // and F1 are compatible.
  template <typename F1, typename F2>
  class ActionAdaptor : public ActionInterface<F1> {
   public:
    typedef typename internal::Function<F1>::Result Result;
    typedef typename internal::Function<F1>::ArgumentTuple ArgumentTuple;
  
    explicit ActionAdaptor(const Action<F2>& from) : impl_(from.impl_) {}
  
    virtual Result Perform(const ArgumentTuple& args) {
      return impl_->Perform(args);
    }
  
   private:
    const internal::linked_ptr<ActionInterface<F2> > impl_;
  
    GTEST_DISALLOW_ASSIGN_(ActionAdaptor);
  };
  
  // Implements the polymorphic Return(x) action, which can be used in
  // any function that returns the type of x, regardless of the argument
  // types.
  //
  // Note: The value passed into Return must be converted into
  // Function<F>::Result when this action is cast to Action<F> rather than
  // when that action is performed. This is important in scenarios like
  //
  // MOCK_METHOD1(Method, T(U));
  // ...
  // {
  //   Foo foo;
  //   X x(&foo);
  //   EXPECT_CALL(mock, Method(_)).WillOnce(Return(x));
  // }
  //
  // In the example above the variable x holds reference to foo which leaves
  // scope and gets destroyed.  If copying X just copies a reference to foo,
  // that copy will be left with a hanging reference.  If conversion to T
  // makes a copy of foo, the above code is safe. To support that scenario, we
  // need to make sure that the type conversion happens inside the EXPECT_CALL
  // statement, and conversion of the result of Return to Action<T(U)> is a
  // good place for that.
  //
  template <typename R>
  class ReturnAction {
   public:
    // Constructs a ReturnAction object from the value to be returned.
    // 'value' is passed by value instead of by const reference in order
    // to allow Return("string literal") to compile.
    explicit ReturnAction(R value) : value_(value) {}
  
    // This template type conversion operator allows Return(x) to be
    // used in ANY function that returns x's type.
    template <typename F>
    operator Action<F>() const {
      // Assert statement belongs here because this is the best place to verify
      // conditions on F. It produces the clearest error messages
      // in most compilers.
      // Impl really belongs in this scope as a local class but can't
      // because MSVC produces duplicate symbols in different translation units
      // in this case. Until MS fixes that bug we put Impl into the class scope
      // and put the typedef both here (for use in assert statement) and
      // in the Impl class. But both definitions must be the same.
      typedef typename Function<F>::Result Result;
      GMOCK_COMPILE_ASSERT_(
          !internal::is_reference<Result>::value,
          use_ReturnRef_instead_of_Return_to_return_a_reference);
      return Action<F>(new Impl<F>(value_));
    }
  
   private:
    // Implements the Return(x) action for a particular function type F.
    template <typename F>
    class Impl : public ActionInterface<F> {
     public:
      typedef typename Function<F>::Result Result;
      typedef typename Function<F>::ArgumentTuple ArgumentTuple;
  
      // The implicit cast is necessary when Result has more than one
      // single-argument constructor (e.g. Result is std::vector<int>) and R
      // has a type conversion operator template.  In that case, value_(value)
      // won't compile as the compiler doesn't known which constructor of
      // Result to call.  implicit_cast forces the compiler to convert R to
      // Result without considering explicit constructors, thus resolving the
      // ambiguity. value_ is then initialized using its copy constructor.
      explicit Impl(R value)
          : value_(::testing::internal::implicit_cast<Result>(value)) {}
  
      virtual Result Perform(const ArgumentTuple&) { return value_; }
  
     private:
      GMOCK_COMPILE_ASSERT_(!internal::is_reference<Result>::value,
                            Result_cannot_be_a_reference_type);
      Result value_;
  
      GTEST_DISALLOW_ASSIGN_(Impl);
    };
  
    R value_;
  
    GTEST_DISALLOW_ASSIGN_(ReturnAction);
  };
  
  // Implements the ReturnNull() action.
  class ReturnNullAction {
   public:
    // Allows ReturnNull() to be used in any pointer-returning function.
    template <typename Result, typename ArgumentTuple>
    static Result Perform(const ArgumentTuple&) {
      GMOCK_COMPILE_ASSERT_(internal::is_pointer<Result>::value,
                            ReturnNull_can_be_used_to_return_a_pointer_only);
      return NULL;
    }
  };
  
  // Implements the Return() action.
  class ReturnVoidAction {
   public:
    // Allows Return() to be used in any void-returning function.
    template <typename Result, typename ArgumentTuple>
    static void Perform(const ArgumentTuple&) {
      CompileAssertTypesEqual<void, Result>();
    }
  };
  
  // Implements the polymorphic ReturnRef(x) action, which can be used
  // in any function that returns a reference to the type of x,
  // regardless of the argument types.
  template <typename T>
  class ReturnRefAction {
   public:
    // Constructs a ReturnRefAction object from the reference to be returned.
    explicit ReturnRefAction(T& ref) : ref_(ref) {}  // NOLINT
  
    // This template type conversion operator allows ReturnRef(x) to be
    // used in ANY function that returns a reference to x's type.
    template <typename F>
    operator Action<F>() const {
      typedef typename Function<F>::Result Result;
      // Asserts that the function return type is a reference.  This
      // catches the user error of using ReturnRef(x) when Return(x)
      // should be used, and generates some helpful error message.
      GMOCK_COMPILE_ASSERT_(internal::is_reference<Result>::value,
                            use_Return_instead_of_ReturnRef_to_return_a_value);
      return Action<F>(new Impl<F>(ref_));
    }
  
   private:
    // Implements the ReturnRef(x) action for a particular function type F.
    template <typename F>
    class Impl : public ActionInterface<F> {
     public:
      typedef typename Function<F>::Result Result;
      typedef typename Function<F>::ArgumentTuple ArgumentTuple;
  
      explicit Impl(T& ref) : ref_(ref) {}  // NOLINT
  
      virtual Result Perform(const ArgumentTuple&) {
        return ref_;
      }
  
     private:
      T& ref_;
  
      GTEST_DISALLOW_ASSIGN_(Impl);
    };
  
    T& ref_;
  
    GTEST_DISALLOW_ASSIGN_(ReturnRefAction);
  };
  
  // Implements the DoDefault() action for a particular function type F.
  template <typename F>
  class MonomorphicDoDefaultActionImpl : public ActionInterface<F> {
   public:
    typedef typename Function<F>::Result Result;
    typedef typename Function<F>::ArgumentTuple ArgumentTuple;
  
    MonomorphicDoDefaultActionImpl() : ActionInterface<F>(true) {}
  
    // For technical reasons, DoDefault() cannot be used inside a
    // composite action (e.g. DoAll(...)).  It can only be used at the
    // top level in an EXPECT_CALL().  If this function is called, the
    // user must be using DoDefault() inside a composite action, and we
    // have to generate a run-time error.
    virtual Result Perform(const ArgumentTuple&) {
      Assert(false, __FILE__, __LINE__,
             "You are using DoDefault() inside a composite action like "
             "DoAll() or WithArgs().  This is not supported for technical "
             "reasons.  Please instead spell out the default action, or "
             "assign the default action to an Action variable and use "
             "the variable in various places.");
      return internal::Invalid<Result>();
      // The above statement will never be reached, but is required in
      // order for this function to compile.
    }
  };
  
  // Implements the polymorphic DoDefault() action.
  class DoDefaultAction {
   public:
    // This template type conversion operator allows DoDefault() to be
    // used in any function.
    template <typename F>
    operator Action<F>() const {
      return Action<F>(new MonomorphicDoDefaultActionImpl<F>);
    }
  };
  
  // Implements the Assign action to set a given pointer referent to a
  // particular value.
  template <typename T1, typename T2>
  class AssignAction {
   public:
    AssignAction(T1* ptr, T2 value) : ptr_(ptr), value_(value) {}
  
    template <typename Result, typename ArgumentTuple>
    void Perform(const ArgumentTuple& /* args */) const {
      *ptr_ = value_;
    }
  
   private:
    T1* const ptr_;
    const T2 value_;
  
    GTEST_DISALLOW_ASSIGN_(AssignAction);
  };
  
  #if !GTEST_OS_WINDOWS_MOBILE
  
  // Implements the SetErrnoAndReturn action to simulate return from
  // various system calls and libc functions.
  template <typename T>
  class SetErrnoAndReturnAction {
   public:
    SetErrnoAndReturnAction(int errno_value, T result)
        : errno_(errno_value),
          result_(result) {}
    template <typename Result, typename ArgumentTuple>
    Result Perform(const ArgumentTuple& /* args */) const {
      errno = errno_;
      return result_;
    }
  
   private:
    const int errno_;
    const T result_;
  
    GTEST_DISALLOW_ASSIGN_(SetErrnoAndReturnAction);
  };
  
  #endif  // !GTEST_OS_WINDOWS_MOBILE
  
  // Implements the SetArgumentPointee<N>(x) action for any function
  // whose N-th argument (0-based) is a pointer to x's type.  The
  // template parameter kIsProto is true iff type A is ProtocolMessage,
  // proto2::Message, or a sub-class of those.
  template <size_t N, typename A, bool kIsProto>
  class SetArgumentPointeeAction {
   public:
    // Constructs an action that sets the variable pointed to by the
    // N-th function argument to 'value'.
    explicit SetArgumentPointeeAction(const A& value) : value_(value) {}
  
    template <typename Result, typename ArgumentTuple>
    void Perform(const ArgumentTuple& args) const {
      CompileAssertTypesEqual<void, Result>();
      *::std::tr1::get<N>(args) = value_;
    }
  
   private:
    const A value_;
  
    GTEST_DISALLOW_ASSIGN_(SetArgumentPointeeAction);
  };
  
  template <size_t N, typename Proto>
  class SetArgumentPointeeAction<N, Proto, true> {
   public:
    // Constructs an action that sets the variable pointed to by the
    // N-th function argument to 'proto'.  Both ProtocolMessage and
    // proto2::Message have the CopyFrom() method, so the same
    // implementation works for both.
    explicit SetArgumentPointeeAction(const Proto& proto) : proto_(new Proto) {
      proto_->CopyFrom(proto);
    }
  
    template <typename Result, typename ArgumentTuple>
    void Perform(const ArgumentTuple& args) const {
      CompileAssertTypesEqual<void, Result>();
      ::std::tr1::get<N>(args)->CopyFrom(*proto_);
    }
  
   private:
    const internal::linked_ptr<Proto> proto_;
  
    GTEST_DISALLOW_ASSIGN_(SetArgumentPointeeAction);
  };
  
  // Implements the InvokeWithoutArgs(f) action.  The template argument
  // FunctionImpl is the implementation type of f, which can be either a
  // function pointer or a functor.  InvokeWithoutArgs(f) can be used as an
  // Action<F> as long as f's type is compatible with F (i.e. f can be
  // assigned to a tr1::function<F>).
  template <typename FunctionImpl>
  class InvokeWithoutArgsAction {
   public:
    // The c'tor makes a copy of function_impl (either a function
    // pointer or a functor).
    explicit InvokeWithoutArgsAction(FunctionImpl function_impl)
        : function_impl_(function_impl) {}
  
    // Allows InvokeWithoutArgs(f) to be used as any action whose type is
    // compatible with f.
    template <typename Result, typename ArgumentTuple>
    Result Perform(const ArgumentTuple&) { return function_impl_(); }
  
   private:
    FunctionImpl function_impl_;
  
    GTEST_DISALLOW_ASSIGN_(InvokeWithoutArgsAction);
  };
  
  // Implements the InvokeWithoutArgs(object_ptr, &Class::Method) action.
  template <class Class, typename MethodPtr>
  class InvokeMethodWithoutArgsAction {
   public:
    InvokeMethodWithoutArgsAction(Class* obj_ptr, MethodPtr method_ptr)
        : obj_ptr_(obj_ptr), method_ptr_(method_ptr) {}
  
    template <typename Result, typename ArgumentTuple>
    Result Perform(const ArgumentTuple&) const {
      return (obj_ptr_->*method_ptr_)();
    }
  
   private:
    Class* const obj_ptr_;
    const MethodPtr method_ptr_;
  
    GTEST_DISALLOW_ASSIGN_(InvokeMethodWithoutArgsAction);
  };
  
  // Implements the IgnoreResult(action) action.
  template <typename A>
  class IgnoreResultAction {
   public:
    explicit IgnoreResultAction(const A& action) : action_(action) {}
  
    template <typename F>
    operator Action<F>() const {
      // Assert statement belongs here because this is the best place to verify
      // conditions on F. It produces the clearest error messages
      // in most compilers.
      // Impl really belongs in this scope as a local class but can't
      // because MSVC produces duplicate symbols in different translation units
      // in this case. Until MS fixes that bug we put Impl into the class scope
      // and put the typedef both here (for use in assert statement) and
      // in the Impl class. But both definitions must be the same.
      typedef typename internal::Function<F>::Result Result;
  
      // Asserts at compile time that F returns void.
      CompileAssertTypesEqual<void, Result>();
  
      return Action<F>(new Impl<F>(action_));
    }
  
   private:
    template <typename F>
    class Impl : public ActionInterface<F> {
     public:
      typedef typename internal::Function<F>::Result Result;
      typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
  
      explicit Impl(const A& action) : action_(action) {}
  
      virtual void Perform(const ArgumentTuple& args) {
        // Performs the action and ignores its result.
        action_.Perform(args);
      }
  
     private:
      // Type OriginalFunction is the same as F except that its return
      // type is IgnoredValue.
      typedef typename internal::Function<F>::MakeResultIgnoredValue
          OriginalFunction;
  
      const Action<OriginalFunction> action_;
  
      GTEST_DISALLOW_ASSIGN_(Impl);
    };
  
    const A action_;
  
    GTEST_DISALLOW_ASSIGN_(IgnoreResultAction);
  };
  
  // A ReferenceWrapper<T> object represents a reference to type T,
  // which can be either const or not.  It can be explicitly converted
  // from, and implicitly converted to, a T&.  Unlike a reference,
  // ReferenceWrapper<T> can be copied and can survive template type
  // inference.  This is used to support by-reference arguments in the
  // InvokeArgument<N>(...) action.  The idea was from "reference
  // wrappers" in tr1, which we don't have in our source tree yet.
  template <typename T>
  class ReferenceWrapper {
   public:
    // Constructs a ReferenceWrapper<T> object from a T&.
    explicit ReferenceWrapper(T& l_value) : pointer_(&l_value) {}  // NOLINT
  
    // Allows a ReferenceWrapper<T> object to be implicitly converted to
    // a T&.
    operator T&() const { return *pointer_; }
   private:
    T* pointer_;
  };
  
  // Allows the expression ByRef(x) to be printed as a reference to x.
  template <typename T>
  void PrintTo(const ReferenceWrapper<T>& ref, ::std::ostream* os) {
    T& value = ref;
    UniversalPrinter<T&>::Print(value, os);
  }
  
  // Does two actions sequentially.  Used for implementing the DoAll(a1,
  // a2, ...) action.
  template <typename Action1, typename Action2>
  class DoBothAction {
   public:
    DoBothAction(Action1 action1, Action2 action2)
        : action1_(action1), action2_(action2) {}
  
    // This template type conversion operator allows DoAll(a1, ..., a_n)
    // to be used in ANY function of compatible type.
    template <typename F>
    operator Action<F>() const {
      return Action<F>(new Impl<F>(action1_, action2_));
    }
  
   private:
    // Implements the DoAll(...) action for a particular function type F.
    template <typename F>
    class Impl : public ActionInterface<F> {
     public:
      typedef typename Function<F>::Result Result;
      typedef typename Function<F>::ArgumentTuple ArgumentTuple;
      typedef typename Function<F>::MakeResultVoid VoidResult;
  
      Impl(const Action<VoidResult>& action1, const Action<F>& action2)
          : action1_(action1), action2_(action2) {}
  
      virtual Result Perform(const ArgumentTuple& args) {
        action1_.Perform(args);
        return action2_.Perform(args);
      }
  
     private:
      const Action<VoidResult> action1_;
      const Action<F> action2_;
  
      GTEST_DISALLOW_ASSIGN_(Impl);
    };
  
    Action1 action1_;
    Action2 action2_;
  
    GTEST_DISALLOW_ASSIGN_(DoBothAction);
  };
  
  }  // namespace internal
  
  // An Unused object can be implicitly constructed from ANY value.
  // This is handy when defining actions that ignore some or all of the
  // mock function arguments.  For example, given
  //
  //   MOCK_METHOD3(Foo, double(const string& label, double x, double y));
  //   MOCK_METHOD3(Bar, double(int index, double x, double y));
  //
  // instead of
  //
  //   double DistanceToOriginWithLabel(const string& label, double x, double y) {
  //     return sqrt(x*x + y*y);
  //   }
  //   double DistanceToOriginWithIndex(int index, double x, double y) {
  //     return sqrt(x*x + y*y);
  //   }
  //   ...
  //   EXEPCT_CALL(mock, Foo("abc", _, _))
  //       .WillOnce(Invoke(DistanceToOriginWithLabel));
  //   EXEPCT_CALL(mock, Bar(5, _, _))
  //       .WillOnce(Invoke(DistanceToOriginWithIndex));
  //
  // you could write
  //
  //   // We can declare any uninteresting argument as Unused.
  //   double DistanceToOrigin(Unused, double x, double y) {
  //     return sqrt(x*x + y*y);
  //   }
  //   ...
  //   EXEPCT_CALL(mock, Foo("abc", _, _)).WillOnce(Invoke(DistanceToOrigin));
  //   EXEPCT_CALL(mock, Bar(5, _, _)).WillOnce(Invoke(DistanceToOrigin));
  typedef internal::IgnoredValue Unused;
  
  // This constructor allows us to turn an Action<From> object into an
  // Action<To>, as long as To's arguments can be implicitly converted
  // to From's and From's return type cann be implicitly converted to
  // To's.
  template <typename To>
  template <typename From>
  Action<To>::Action(const Action<From>& from)
      : impl_(new internal::ActionAdaptor<To, From>(from)) {}
  
  // Creates an action that returns 'value'.  'value' is passed by value
  // instead of const reference - otherwise Return("string literal")
  // will trigger a compiler error about using array as initializer.
  template <typename R>
  internal::ReturnAction<R> Return(R value) {
    return internal::ReturnAction<R>(value);
  }
  
  // Creates an action that returns NULL.
  inline PolymorphicAction<internal::ReturnNullAction> ReturnNull() {
    return MakePolymorphicAction(internal::ReturnNullAction());
  }
  
  // Creates an action that returns from a void function.
  inline PolymorphicAction<internal::ReturnVoidAction> Return() {
    return MakePolymorphicAction(internal::ReturnVoidAction());
  }
  
  // Creates an action that returns the reference to a variable.
  template <typename R>
  inline internal::ReturnRefAction<R> ReturnRef(R& x) {  // NOLINT
    return internal::ReturnRefAction<R>(x);
  }
  
  // Creates an action that does the default action for the give mock function.
  inline internal::DoDefaultAction DoDefault() {
    return internal::DoDefaultAction();
  }
  
  // Creates an action that sets the variable pointed by the N-th
  // (0-based) function argument to 'value'.
  template <size_t N, typename T>
  PolymorphicAction<
    internal::SetArgumentPointeeAction<
      N, T, internal::IsAProtocolMessage<T>::value> >
  SetArgumentPointee(const T& x) {
    return MakePolymorphicAction(internal::SetArgumentPointeeAction<
        N, T, internal::IsAProtocolMessage<T>::value>(x));
  }
  
  // Creates an action that sets a pointer referent to a given value.
  template <typename T1, typename T2>
  PolymorphicAction<internal::AssignAction<T1, T2> > Assign(T1* ptr, T2 val) {
    return MakePolymorphicAction(internal::AssignAction<T1, T2>(ptr, val));
  }
  
  #if !GTEST_OS_WINDOWS_MOBILE
  
  // Creates an action that sets errno and returns the appropriate error.
  template <typename T>
  PolymorphicAction<internal::SetErrnoAndReturnAction<T> >
  SetErrnoAndReturn(int errval, T result) {
    return MakePolymorphicAction(
        internal::SetErrnoAndReturnAction<T>(errval, result));
  }
  
  #endif  // !GTEST_OS_WINDOWS_MOBILE
  
  // Various overloads for InvokeWithoutArgs().
  
  // Creates an action that invokes 'function_impl' with no argument.
  template <typename FunctionImpl>
  PolymorphicAction<internal::InvokeWithoutArgsAction<FunctionImpl> >
  InvokeWithoutArgs(FunctionImpl function_impl) {
    return MakePolymorphicAction(
        internal::InvokeWithoutArgsAction<FunctionImpl>(function_impl));
  }
  
  // Creates an action that invokes the given method on the given object
  // with no argument.
  template <class Class, typename MethodPtr>
  PolymorphicAction<internal::InvokeMethodWithoutArgsAction<Class, MethodPtr> >
  InvokeWithoutArgs(Class* obj_ptr, MethodPtr method_ptr) {
    return MakePolymorphicAction(
        internal::InvokeMethodWithoutArgsAction<Class, MethodPtr>(
            obj_ptr, method_ptr));
  }
  
  // Creates an action that performs an_action and throws away its
  // result.  In other words, it changes the return type of an_action to
  // void.  an_action MUST NOT return void, or the code won't compile.
  template <typename A>
  inline internal::IgnoreResultAction<A> IgnoreResult(const A& an_action) {
    return internal::IgnoreResultAction<A>(an_action);
  }
  
  // Creates a reference wrapper for the given L-value.  If necessary,
  // you can explicitly specify the type of the reference.  For example,
  // suppose 'derived' is an object of type Derived, ByRef(derived)
  // would wrap a Derived&.  If you want to wrap a const Base& instead,
  // where Base is a base class of Derived, just write:
  //
  //   ByRef<const Base>(derived)
  template <typename T>
  inline internal::ReferenceWrapper<T> ByRef(T& l_value) {  // NOLINT
    return internal::ReferenceWrapper<T>(l_value);
  }
  
  }  // namespace testing
  
  #endif  // GMOCK_INCLUDE_GMOCK_GMOCK_ACTIONS_H_
  