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Action

ActionAdaptor

ActionInterface

AssignAction

BuiltInDefaultValue

BuiltInDefaultValue

BuiltInDefaultValue

DefaultValue

DefaultValue

DefaultValue

DoBothAction

DoDefaultAction

IgnoreResultAction

Impl

Impl

Impl

Impl

Impl

InvokeMethodWithoutArgsAction

InvokeWithoutArgsAction

MonomorphicImpl

PolymorphicAction

ReferenceWrapper

ReturnAction

ReturnNullAction

ReturnRefAction

ReturnRefOfCopyAction

ReturnVoidAction

SetArgumentPointeeAction

SetArgumentPointeeAction

SetErrnoAndReturnAction

Macros

Line Code
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// Copyright 2007, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// 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/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 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() {}
  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;

 private:
  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.  A NULL impl is
  // used to represent the "do-default" action.
  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_.get() == NULL; }

  // 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 {
    internal::Assert(
        !IsDoDefault(), __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 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;
    GTEST_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.  ImplicitCast_ 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::ImplicitCast_<Result>(value)) {}

    virtual Result Perform(const ArgumentTuple&) { return value_; }

   private:
    GTEST_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&) {
    GTEST_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.
    GTEST_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 polymorphic ReturnRefOfCopy(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 ReturnRefOfCopyAction {
 public:
  // Constructs a ReturnRefOfCopyAction object from the reference to
  // be returned.
  explicit ReturnRefOfCopyAction(const T& value) : value_(value) {}  // NOLINT

  // This template type conversion operator allows ReturnRefOfCopy(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 ReturnRefOfCopy(x) when Return(x)
    // should be used, and generates some helpful error message.
    GTEST_COMPILE_ASSERT_(
        internal::is_reference<Result>::value,
        use_Return_instead_of_ReturnRefOfCopy_to_return_a_value);
    return Action<F>(new Impl<F>(value_));
  }

 private:
  // Implements the ReturnRefOfCopy(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(const T& value) : value_(value) {}  // NOLINT

    virtual Result Perform(const ArgumentTuple&) {
      return value_;
    }

   private:
    T value_;

    GTEST_DISALLOW_ASSIGN_(Impl);
  };

  const T value_;

  GTEST_DISALLOW_ASSIGN_(ReturnRefOfCopyAction);
};

// 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>(NULL); }
};

// 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 returns the reference to a copy of the
// argument.  The copy is created when the action is constructed and
// lives as long as the action.
template <typename R>
inline internal::ReturnRefOfCopyAction<R> ReturnRefOfCopy(const R& x) {
  return internal::ReturnRefOfCopyAction<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> >
SetArgPointee(const T& x) {
  return MakePolymorphicAction(internal::SetArgumentPointeeAction<
      N, T, internal::IsAProtocolMessage<T>::value>(x));
}

#if !((GTEST_GCC_VER_ && GTEST_GCC_VER_ < 40000) || GTEST_OS_SYMBIAN)
// This overload allows SetArgPointee() to accept a string literal.
// GCC prior to the version 4.0 and Symbian C++ compiler cannot distinguish
// this overload from the templated version and emit a compile error.
template <size_t N>
PolymorphicAction<
  internal::SetArgumentPointeeAction<N, const char*, false> >
SetArgPointee(const char* p) {
  return MakePolymorphicAction(internal::SetArgumentPointeeAction<
      N, const char*, false>(p));
}

template <size_t N>
PolymorphicAction<
  internal::SetArgumentPointeeAction<N, const wchar_t*, false> >
SetArgPointee(const wchar_t* p) {
  return MakePolymorphicAction(internal::SetArgumentPointeeAction<
      N, const wchar_t*, false>(p));
}
#endif

// The following version is DEPRECATED.
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