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gmock-spec-builders.h (82086B)

---

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//
//     * Redistributions of source code must retain the above copyright
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// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
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// contributors may be used to endorse or promote products derived from
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//
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// Google Mock - a framework for writing C++ mock classes.
//
// This file implements the ON_CALL() and EXPECT_CALL() macros.
//
// A user can use the ON_CALL() macro to specify the default action of
// a mock method.  The syntax is:
//
//   ON_CALL(mock_object, Method(argument-matchers))
//       .With(multi-argument-matcher)
//       .WillByDefault(action);
//
//  where the .With() clause is optional.
//
// A user can use the EXPECT_CALL() macro to specify an expectation on
// a mock method.  The syntax is:
//
//   EXPECT_CALL(mock_object, Method(argument-matchers))
//       .With(multi-argument-matchers)
//       .Times(cardinality)
//       .InSequence(sequences)
//       .After(expectations)
//       .WillOnce(action)
//       .WillRepeatedly(action)
//       .RetiresOnSaturation();
//
// where all clauses are optional, and .InSequence()/.After()/
// .WillOnce() can appear any number of times.

// IWYU pragma: private, include "gmock/gmock.h"
// IWYU pragma: friend gmock/.*

#ifndef GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_SPEC_BUILDERS_H_
#define GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_SPEC_BUILDERS_H_

#include <cstdint>
#include <functional>
#include <map>
#include <memory>
#include <ostream>
#include <set>
#include <sstream>
#include <string>
#include <type_traits>
#include <utility>
#include <vector>

#include "gmock/gmock-actions.h"
#include "gmock/gmock-cardinalities.h"
#include "gmock/gmock-matchers.h"
#include "gmock/internal/gmock-internal-utils.h"
#include "gmock/internal/gmock-port.h"
#include "gtest/gtest.h"

#if GTEST_HAS_EXCEPTIONS
#include <stdexcept>  // NOLINT
#endif

GTEST_DISABLE_MSC_WARNINGS_PUSH_(4251 \
/* class A needs to have dll-interface to be used by clients of class B */)

namespace testing {

// An abstract handle of an expectation.
class Expectation;

// A set of expectation handles.
class ExpectationSet;

// Anything inside the 'internal' namespace IS INTERNAL IMPLEMENTATION
// and MUST NOT BE USED IN USER CODE!!!
namespace internal {

// Implements a mock function.
template <typename F>
class FunctionMocker;

// Base class for expectations.
class ExpectationBase;

// Implements an expectation.
template <typename F>
class TypedExpectation;

// Helper class for testing the Expectation class template.
class ExpectationTester;

// Helper classes for implementing NiceMock, StrictMock, and NaggyMock.
template <typename MockClass>
class NiceMockImpl;
template <typename MockClass>
class StrictMockImpl;
template <typename MockClass>
class NaggyMockImpl;

// Protects the mock object registry (in class Mock), all function
// mockers, and all expectations.
//
// The reason we don't use more fine-grained protection is: when a
// mock function Foo() is called, it needs to consult its expectations
// to see which one should be picked.  If another thread is allowed to
// call a mock function (either Foo() or a different one) at the same
// time, it could affect the "retired" attributes of Foo()'s
// expectations when InSequence() is used, and thus affect which
// expectation gets picked.  Therefore, we sequence all mock function
// calls to ensure the integrity of the mock objects' states.
GTEST_API_ GTEST_DECLARE_STATIC_MUTEX_(g_gmock_mutex);

// Abstract base class of FunctionMocker.  This is the
// type-agnostic part of the function mocker interface.  Its pure
// virtual methods are implemented by FunctionMocker.
class GTEST_API_ UntypedFunctionMockerBase {
public:
 UntypedFunctionMockerBase();
 virtual ~UntypedFunctionMockerBase();

 // Verifies that all expectations on this mock function have been
 // satisfied.  Reports one or more Google Test non-fatal failures
 // and returns false if not.
 bool VerifyAndClearExpectationsLocked()
     GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex);

 // Clears the ON_CALL()s set on this mock function.
 virtual void ClearDefaultActionsLocked()
     GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) = 0;

 // In all of the following Untyped* functions, it's the caller's
 // responsibility to guarantee the correctness of the arguments'
 // types.

 // Writes a message that the call is uninteresting (i.e. neither
 // explicitly expected nor explicitly unexpected) to the given
 // ostream.
 virtual void UntypedDescribeUninterestingCall(const void* untyped_args,
                                               ::std::ostream* os) const
     GTEST_LOCK_EXCLUDED_(g_gmock_mutex) = 0;

 // Returns the expectation that matches the given function arguments
 // (or NULL is there's no match); when a match is found,
 // untyped_action is set to point to the action that should be
 // performed (or NULL if the action is "do default"), and
 // is_excessive is modified to indicate whether the call exceeds the
 // expected number.
 virtual const ExpectationBase* UntypedFindMatchingExpectation(
     const void* untyped_args, const void** untyped_action, bool* is_excessive,
     ::std::ostream* what, ::std::ostream* why)
     GTEST_LOCK_EXCLUDED_(g_gmock_mutex) = 0;

 // Prints the given function arguments to the ostream.
 virtual void UntypedPrintArgs(const void* untyped_args,
                               ::std::ostream* os) const = 0;

 // Sets the mock object this mock method belongs to, and registers
 // this information in the global mock registry.  Will be called
 // whenever an EXPECT_CALL() or ON_CALL() is executed on this mock
 // method.
 void RegisterOwner(const void* mock_obj) GTEST_LOCK_EXCLUDED_(g_gmock_mutex);

 // Sets the mock object this mock method belongs to, and sets the
 // name of the mock function.  Will be called upon each invocation
 // of this mock function.
 void SetOwnerAndName(const void* mock_obj, const char* name)
     GTEST_LOCK_EXCLUDED_(g_gmock_mutex);

 // Returns the mock object this mock method belongs to.  Must be
 // called after RegisterOwner() or SetOwnerAndName() has been
 // called.
 const void* MockObject() const GTEST_LOCK_EXCLUDED_(g_gmock_mutex);

 // Returns the name of this mock method.  Must be called after
 // SetOwnerAndName() has been called.
 const char* Name() const GTEST_LOCK_EXCLUDED_(g_gmock_mutex);

protected:
 typedef std::vector<const void*> UntypedOnCallSpecs;

 using UntypedExpectations = std::vector<std::shared_ptr<ExpectationBase>>;

 struct UninterestingCallCleanupHandler;
 struct FailureCleanupHandler;

 // Returns an Expectation object that references and co-owns exp,
 // which must be an expectation on this mock function.
 Expectation GetHandleOf(ExpectationBase* exp);

 // Address of the mock object this mock method belongs to.  Only
 // valid after this mock method has been called or
 // ON_CALL/EXPECT_CALL has been invoked on it.
 const void* mock_obj_;  // Protected by g_gmock_mutex.

 // Name of the function being mocked.  Only valid after this mock
 // method has been called.
 const char* name_;  // Protected by g_gmock_mutex.

 // All default action specs for this function mocker.
 UntypedOnCallSpecs untyped_on_call_specs_;

 // All expectations for this function mocker.
 //
 // It's undefined behavior to interleave expectations (EXPECT_CALLs
 // or ON_CALLs) and mock function calls.  Also, the order of
 // expectations is important.  Therefore it's a logic race condition
 // to read/write untyped_expectations_ concurrently.  In order for
 // tools like tsan to catch concurrent read/write accesses to
 // untyped_expectations, we deliberately leave accesses to it
 // unprotected.
 UntypedExpectations untyped_expectations_;
};  // class UntypedFunctionMockerBase

// Untyped base class for OnCallSpec<F>.
class UntypedOnCallSpecBase {
public:
 // The arguments are the location of the ON_CALL() statement.
 UntypedOnCallSpecBase(const char* a_file, int a_line)
     : file_(a_file), line_(a_line), last_clause_(kNone) {}

 // Where in the source file was the default action spec defined?
 const char* file() const { return file_; }
 int line() const { return line_; }

protected:
 // Gives each clause in the ON_CALL() statement a name.
 enum Clause {
   // Do not change the order of the enum members!  The run-time
   // syntax checking relies on it.
   kNone,
   kWith,
   kWillByDefault
 };

 // Asserts that the ON_CALL() statement has a certain property.
 void AssertSpecProperty(bool property,
                         const std::string& failure_message) const {
   Assert(property, file_, line_, failure_message);
 }

 // Expects that the ON_CALL() statement has a certain property.
 void ExpectSpecProperty(bool property,
                         const std::string& failure_message) const {
   Expect(property, file_, line_, failure_message);
 }

 const char* file_;
 int line_;

 // The last clause in the ON_CALL() statement as seen so far.
 // Initially kNone and changes as the statement is parsed.
 Clause last_clause_;
};  // class UntypedOnCallSpecBase

// This template class implements an ON_CALL spec.
template <typename F>
class OnCallSpec : public UntypedOnCallSpecBase {
public:
 typedef typename Function<F>::ArgumentTuple ArgumentTuple;
 typedef typename Function<F>::ArgumentMatcherTuple ArgumentMatcherTuple;

 // Constructs an OnCallSpec object from the information inside
 // the parenthesis of an ON_CALL() statement.
 OnCallSpec(const char* a_file, int a_line,
            const ArgumentMatcherTuple& matchers)
     : UntypedOnCallSpecBase(a_file, a_line),
       matchers_(matchers),
       // By default, extra_matcher_ should match anything.  However,
       // we cannot initialize it with _ as that causes ambiguity between
       // Matcher's copy and move constructor for some argument types.
       extra_matcher_(A<const ArgumentTuple&>()) {}

 // Implements the .With() clause.
 OnCallSpec& With(const Matcher<const ArgumentTuple&>& m) {
   // Makes sure this is called at most once.
   ExpectSpecProperty(last_clause_ < kWith,
                      ".With() cannot appear "
                      "more than once in an ON_CALL().");
   last_clause_ = kWith;

   extra_matcher_ = m;
   return *this;
 }

 // Implements the .WillByDefault() clause.
 OnCallSpec& WillByDefault(const Action<F>& action) {
   ExpectSpecProperty(last_clause_ < kWillByDefault,
                      ".WillByDefault() must appear "
                      "exactly once in an ON_CALL().");
   last_clause_ = kWillByDefault;

   ExpectSpecProperty(!action.IsDoDefault(),
                      "DoDefault() cannot be used in ON_CALL().");
   action_ = action;
   return *this;
 }

 // Returns true if and only if the given arguments match the matchers.
 bool Matches(const ArgumentTuple& args) const {
   return TupleMatches(matchers_, args) && extra_matcher_.Matches(args);
 }

 // Returns the action specified by the user.
 const Action<F>& GetAction() const {
   AssertSpecProperty(last_clause_ == kWillByDefault,
                      ".WillByDefault() must appear exactly "
                      "once in an ON_CALL().");
   return action_;
 }

private:
 // The information in statement
 //
 //   ON_CALL(mock_object, Method(matchers))
 //       .With(multi-argument-matcher)
 //       .WillByDefault(action);
 //
 // is recorded in the data members like this:
 //
 //   source file that contains the statement => file_
 //   line number of the statement            => line_
 //   matchers                                => matchers_
 //   multi-argument-matcher                  => extra_matcher_
 //   action                                  => action_
 ArgumentMatcherTuple matchers_;
 Matcher<const ArgumentTuple&> extra_matcher_;
 Action<F> action_;
};  // class OnCallSpec

// Possible reactions on uninteresting calls.
enum CallReaction {
 kAllow,
 kWarn,
 kFail,
};

}  // namespace internal

// Utilities for manipulating mock objects.
class GTEST_API_ Mock {
public:
 // The following public methods can be called concurrently.

 // Tells Google Mock to ignore mock_obj when checking for leaked
 // mock objects.
 static void AllowLeak(const void* mock_obj)
     GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);

 // Verifies and clears all expectations on the given mock object.
 // If the expectations aren't satisfied, generates one or more
 // Google Test non-fatal failures and returns false.
 static bool VerifyAndClearExpectations(void* mock_obj)
     GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);

 // Verifies all expectations on the given mock object and clears its
 // default actions and expectations.  Returns true if and only if the
 // verification was successful.
 static bool VerifyAndClear(void* mock_obj)
     GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);

 // Returns whether the mock was created as a naggy mock (default)
 static bool IsNaggy(void* mock_obj)
     GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);
 // Returns whether the mock was created as a nice mock
 static bool IsNice(void* mock_obj)
     GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);
 // Returns whether the mock was created as a strict mock
 static bool IsStrict(void* mock_obj)
     GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);

private:
 friend class internal::UntypedFunctionMockerBase;

 // Needed for a function mocker to register itself (so that we know
 // how to clear a mock object).
 template <typename F>
 friend class internal::FunctionMocker;

 template <typename MockClass>
 friend class internal::NiceMockImpl;
 template <typename MockClass>
 friend class internal::NaggyMockImpl;
 template <typename MockClass>
 friend class internal::StrictMockImpl;

 // Tells Google Mock to allow uninteresting calls on the given mock
 // object.
 static void AllowUninterestingCalls(uintptr_t mock_obj)
     GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);

 // Tells Google Mock to warn the user about uninteresting calls on
 // the given mock object.
 static void WarnUninterestingCalls(uintptr_t mock_obj)
     GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);

 // Tells Google Mock to fail uninteresting calls on the given mock
 // object.
 static void FailUninterestingCalls(uintptr_t mock_obj)
     GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);

 // Tells Google Mock the given mock object is being destroyed and
 // its entry in the call-reaction table should be removed.
 static void UnregisterCallReaction(uintptr_t mock_obj)
     GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);

 // Returns the reaction Google Mock will have on uninteresting calls
 // made on the given mock object.
 static internal::CallReaction GetReactionOnUninterestingCalls(
     const void* mock_obj) GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);

 // Verifies that all expectations on the given mock object have been
 // satisfied.  Reports one or more Google Test non-fatal failures
 // and returns false if not.
 static bool VerifyAndClearExpectationsLocked(void* mock_obj)
     GTEST_EXCLUSIVE_LOCK_REQUIRED_(internal::g_gmock_mutex);

 // Clears all ON_CALL()s set on the given mock object.
 static void ClearDefaultActionsLocked(void* mock_obj)
     GTEST_EXCLUSIVE_LOCK_REQUIRED_(internal::g_gmock_mutex);

 // Registers a mock object and a mock method it owns.
 static void Register(const void* mock_obj,
                      internal::UntypedFunctionMockerBase* mocker)
     GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);

 // Tells Google Mock where in the source code mock_obj is used in an
 // ON_CALL or EXPECT_CALL.  In case mock_obj is leaked, this
 // information helps the user identify which object it is.
 static void RegisterUseByOnCallOrExpectCall(const void* mock_obj,
                                             const char* file, int line)
     GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);

 // Unregisters a mock method; removes the owning mock object from
 // the registry when the last mock method associated with it has
 // been unregistered.  This is called only in the destructor of
 // FunctionMocker.
 static void UnregisterLocked(internal::UntypedFunctionMockerBase* mocker)
     GTEST_EXCLUSIVE_LOCK_REQUIRED_(internal::g_gmock_mutex);
};  // class Mock

// An abstract handle of an expectation.  Useful in the .After()
// clause of EXPECT_CALL() for setting the (partial) order of
// expectations.  The syntax:
//
//   Expectation e1 = EXPECT_CALL(...)...;
//   EXPECT_CALL(...).After(e1)...;
//
// sets two expectations where the latter can only be matched after
// the former has been satisfied.
//
// Notes:
//   - This class is copyable and has value semantics.
//   - Constness is shallow: a const Expectation object itself cannot
//     be modified, but the mutable methods of the ExpectationBase
//     object it references can be called via expectation_base().

class GTEST_API_ Expectation {
public:
 // Constructs a null object that doesn't reference any expectation.
 Expectation();
 Expectation(Expectation&&) = default;
 Expectation(const Expectation&) = default;
 Expectation& operator=(Expectation&&) = default;
 Expectation& operator=(const Expectation&) = default;
 ~Expectation();

 // This single-argument ctor must not be explicit, in order to support the
 //   Expectation e = EXPECT_CALL(...);
 // syntax.
 //
 // A TypedExpectation object stores its pre-requisites as
 // Expectation objects, and needs to call the non-const Retire()
 // method on the ExpectationBase objects they reference.  Therefore
 // Expectation must receive a *non-const* reference to the
 // ExpectationBase object.
 Expectation(internal::ExpectationBase& exp);  // NOLINT

 // The compiler-generated copy ctor and operator= work exactly as
 // intended, so we don't need to define our own.

 // Returns true if and only if rhs references the same expectation as this
 // object does.
 bool operator==(const Expectation& rhs) const {
   return expectation_base_ == rhs.expectation_base_;
 }

 bool operator!=(const Expectation& rhs) const { return !(*this == rhs); }

private:
 friend class ExpectationSet;
 friend class Sequence;
 friend class ::testing::internal::ExpectationBase;
 friend class ::testing::internal::UntypedFunctionMockerBase;

 template <typename F>
 friend class ::testing::internal::FunctionMocker;

 template <typename F>
 friend class ::testing::internal::TypedExpectation;

 // This comparator is needed for putting Expectation objects into a set.
 class Less {
  public:
   bool operator()(const Expectation& lhs, const Expectation& rhs) const {
     return lhs.expectation_base_.get() < rhs.expectation_base_.get();
   }
 };

 typedef ::std::set<Expectation, Less> Set;

 Expectation(
     const std::shared_ptr<internal::ExpectationBase>& expectation_base);

 // Returns the expectation this object references.
 const std::shared_ptr<internal::ExpectationBase>& expectation_base() const {
   return expectation_base_;
 }

 // A shared_ptr that co-owns the expectation this handle references.
 std::shared_ptr<internal::ExpectationBase> expectation_base_;
};

// A set of expectation handles.  Useful in the .After() clause of
// EXPECT_CALL() for setting the (partial) order of expectations.  The
// syntax:
//
//   ExpectationSet es;
//   es += EXPECT_CALL(...)...;
//   es += EXPECT_CALL(...)...;
//   EXPECT_CALL(...).After(es)...;
//
// sets three expectations where the last one can only be matched
// after the first two have both been satisfied.
//
// This class is copyable and has value semantics.
class ExpectationSet {
public:
 // A bidirectional iterator that can read a const element in the set.
 typedef Expectation::Set::const_iterator const_iterator;

 // An object stored in the set.  This is an alias of Expectation.
 typedef Expectation::Set::value_type value_type;

 // Constructs an empty set.
 ExpectationSet() = default;

 // This single-argument ctor must not be explicit, in order to support the
 //   ExpectationSet es = EXPECT_CALL(...);
 // syntax.
 ExpectationSet(internal::ExpectationBase& exp) {  // NOLINT
   *this += Expectation(exp);
 }

 // This single-argument ctor implements implicit conversion from
 // Expectation and thus must not be explicit.  This allows either an
 // Expectation or an ExpectationSet to be used in .After().
 ExpectationSet(const Expectation& e) {  // NOLINT
   *this += e;
 }

 // The compiler-generator ctor and operator= works exactly as
 // intended, so we don't need to define our own.

 // Returns true if and only if rhs contains the same set of Expectation
 // objects as this does.
 bool operator==(const ExpectationSet& rhs) const {
   return expectations_ == rhs.expectations_;
 }

 bool operator!=(const ExpectationSet& rhs) const { return !(*this == rhs); }

 // Implements the syntax
 //   expectation_set += EXPECT_CALL(...);
 ExpectationSet& operator+=(const Expectation& e) {
   expectations_.insert(e);
   return *this;
 }

 int size() const { return static_cast<int>(expectations_.size()); }

 const_iterator begin() const { return expectations_.begin(); }
 const_iterator end() const { return expectations_.end(); }

private:
 Expectation::Set expectations_;
};

// Sequence objects are used by a user to specify the relative order
// in which the expectations should match.  They are copyable (we rely
// on the compiler-defined copy constructor and assignment operator).
class GTEST_API_ Sequence {
public:
 // Constructs an empty sequence.
 Sequence() : last_expectation_(new Expectation) {}

 // Adds an expectation to this sequence.  The caller must ensure
 // that no other thread is accessing this Sequence object.
 void AddExpectation(const Expectation& expectation) const;

private:
 // The last expectation in this sequence.
 std::shared_ptr<Expectation> last_expectation_;
};  // class Sequence

// An object of this type causes all EXPECT_CALL() statements
// encountered in its scope to be put in an anonymous sequence.  The
// work is done in the constructor and destructor.  You should only
// create an InSequence object on the stack.
//
// The sole purpose for this class is to support easy definition of
// sequential expectations, e.g.
//
//   {
//     InSequence dummy;  // The name of the object doesn't matter.
//
//     // The following expectations must match in the order they appear.
//     EXPECT_CALL(a, Bar())...;
//     EXPECT_CALL(a, Baz())...;
//     ...
//     EXPECT_CALL(b, Xyz())...;
//   }
//
// You can create InSequence objects in multiple threads, as long as
// they are used to affect different mock objects.  The idea is that
// each thread can create and set up its own mocks as if it's the only
// thread.  However, for clarity of your tests we recommend you to set
// up mocks in the main thread unless you have a good reason not to do
// so.
class GTEST_API_ InSequence {
public:
 InSequence();
 ~InSequence();

private:
 bool sequence_created_;

 InSequence(const InSequence&) = delete;
 InSequence& operator=(const InSequence&) = delete;
};

namespace internal {

// Points to the implicit sequence introduced by a living InSequence
// object (if any) in the current thread or NULL.
GTEST_API_ extern ThreadLocal<Sequence*> g_gmock_implicit_sequence;

// Base class for implementing expectations.
//
// There are two reasons for having a type-agnostic base class for
// Expectation:
//
//   1. We need to store collections of expectations of different
//   types (e.g. all pre-requisites of a particular expectation, all
//   expectations in a sequence).  Therefore these expectation objects
//   must share a common base class.
//
//   2. We can avoid binary code bloat by moving methods not depending
//   on the template argument of Expectation to the base class.
//
// This class is internal and mustn't be used by user code directly.
class GTEST_API_ ExpectationBase {
public:
 // source_text is the EXPECT_CALL(...) source that created this Expectation.
 ExpectationBase(const char* file, int line, const std::string& source_text);

 virtual ~ExpectationBase();

 // Where in the source file was the expectation spec defined?
 const char* file() const { return file_; }
 int line() const { return line_; }
 const char* source_text() const { return source_text_.c_str(); }
 // Returns the cardinality specified in the expectation spec.
 const Cardinality& cardinality() const { return cardinality_; }

 // Describes the source file location of this expectation.
 void DescribeLocationTo(::std::ostream* os) const {
   *os << FormatFileLocation(file(), line()) << " ";
 }

 // Describes how many times a function call matching this
 // expectation has occurred.
 void DescribeCallCountTo(::std::ostream* os) const
     GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex);

 // If this mock method has an extra matcher (i.e. .With(matcher)),
 // describes it to the ostream.
 virtual void MaybeDescribeExtraMatcherTo(::std::ostream* os) = 0;

 // Do not rely on this for correctness.
 // This is only for making human-readable test output easier to understand.
 void UntypedDescription(std::string description) {
   description_ = std::move(description);
 }

protected:
 friend class ::testing::Expectation;
 friend class UntypedFunctionMockerBase;

 enum Clause {
   // Don't change the order of the enum members!
   kNone,
   kWith,
   kTimes,
   kInSequence,
   kAfter,
   kWillOnce,
   kWillRepeatedly,
   kRetiresOnSaturation
 };

 typedef std::vector<const void*> UntypedActions;

 // Returns an Expectation object that references and co-owns this
 // expectation.
 virtual Expectation GetHandle() = 0;

 // Asserts that the EXPECT_CALL() statement has the given property.
 void AssertSpecProperty(bool property,
                         const std::string& failure_message) const {
   Assert(property, file_, line_, failure_message);
 }

 // Expects that the EXPECT_CALL() statement has the given property.
 void ExpectSpecProperty(bool property,
                         const std::string& failure_message) const {
   Expect(property, file_, line_, failure_message);
 }

 // Explicitly specifies the cardinality of this expectation.  Used
 // by the subclasses to implement the .Times() clause.
 void SpecifyCardinality(const Cardinality& cardinality);

 // Returns true if and only if the user specified the cardinality
 // explicitly using a .Times().
 bool cardinality_specified() const { return cardinality_specified_; }

 // Sets the cardinality of this expectation spec.
 void set_cardinality(const Cardinality& a_cardinality) {
   cardinality_ = a_cardinality;
 }

 // The following group of methods should only be called after the
 // EXPECT_CALL() statement, and only when g_gmock_mutex is held by
 // the current thread.

 // Retires all pre-requisites of this expectation.
 void RetireAllPreRequisites() GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex);

 // Returns true if and only if this expectation is retired.
 bool is_retired() const GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
   g_gmock_mutex.AssertHeld();
   return retired_;
 }

 // Retires this expectation.
 void Retire() GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
   g_gmock_mutex.AssertHeld();
   retired_ = true;
 }

 // Returns a human-readable description of this expectation.
 // Do not rely on this for correctness. It is only for human readability.
 const std::string& GetDescription() const { return description_; }

 // Returns true if and only if this expectation is satisfied.
 bool IsSatisfied() const GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
   g_gmock_mutex.AssertHeld();
   return cardinality().IsSatisfiedByCallCount(call_count_);
 }

 // Returns true if and only if this expectation is saturated.
 bool IsSaturated() const GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
   g_gmock_mutex.AssertHeld();
   return cardinality().IsSaturatedByCallCount(call_count_);
 }

 // Returns true if and only if this expectation is over-saturated.
 bool IsOverSaturated() const GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
   g_gmock_mutex.AssertHeld();
   return cardinality().IsOverSaturatedByCallCount(call_count_);
 }

 // Returns true if and only if all pre-requisites of this expectation are
 // satisfied.
 bool AllPrerequisitesAreSatisfied() const
     GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex);

 // Adds unsatisfied pre-requisites of this expectation to 'result'.
 void FindUnsatisfiedPrerequisites(ExpectationSet* result) const
     GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex);

 // Returns the number this expectation has been invoked.
 int call_count() const GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
   g_gmock_mutex.AssertHeld();
   return call_count_;
 }

 // Increments the number this expectation has been invoked.
 void IncrementCallCount() GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
   g_gmock_mutex.AssertHeld();
   call_count_++;
 }

 // Checks the action count (i.e. the number of WillOnce() and
 // WillRepeatedly() clauses) against the cardinality if this hasn't
 // been done before.  Prints a warning if there are too many or too
 // few actions.
 void CheckActionCountIfNotDone() const GTEST_LOCK_EXCLUDED_(mutex_);

 friend class ::testing::Sequence;
 friend class ::testing::internal::ExpectationTester;

 template <typename Function>
 friend class TypedExpectation;

 // Implements the .Times() clause.
 void UntypedTimes(const Cardinality& a_cardinality);

 // This group of fields are part of the spec and won't change after
 // an EXPECT_CALL() statement finishes.
 const char* file_;               // The file that contains the expectation.
 int line_;                       // The line number of the expectation.
 const std::string source_text_;  // The EXPECT_CALL(...) source text.
 std::string description_;        // User-readable name for the expectation.
 // True if and only if the cardinality is specified explicitly.
 bool cardinality_specified_;
 Cardinality cardinality_;  // The cardinality of the expectation.
 // The immediate pre-requisites (i.e. expectations that must be
 // satisfied before this expectation can be matched) of this
 // expectation.  We use std::shared_ptr in the set because we want an
 // Expectation object to be co-owned by its FunctionMocker and its
 // successors.  This allows multiple mock objects to be deleted at
 // different times.
 ExpectationSet immediate_prerequisites_;

 // This group of fields are the current state of the expectation,
 // and can change as the mock function is called.
 int call_count_;  // How many times this expectation has been invoked.
 bool retired_;    // True if and only if this expectation has retired.
 UntypedActions untyped_actions_;
 bool extra_matcher_specified_;
 bool repeated_action_specified_;  // True if a WillRepeatedly() was specified.
 bool retires_on_saturation_;
 Clause last_clause_;
 mutable bool action_count_checked_;  // Under mutex_.
 mutable Mutex mutex_;                // Protects action_count_checked_.
};  // class ExpectationBase

template <typename F>
class TypedExpectation;

// Implements an expectation for the given function type.
template <typename R, typename... Args>
class TypedExpectation<R(Args...)> : public ExpectationBase {
private:
 using F = R(Args...);

public:
 typedef typename Function<F>::ArgumentTuple ArgumentTuple;
 typedef typename Function<F>::ArgumentMatcherTuple ArgumentMatcherTuple;
 typedef typename Function<F>::Result Result;

 TypedExpectation(FunctionMocker<F>* owner, const char* a_file, int a_line,
                  const std::string& a_source_text,
                  const ArgumentMatcherTuple& m)
     : ExpectationBase(a_file, a_line, a_source_text),
       owner_(owner),
       matchers_(m),
       // By default, extra_matcher_ should match anything.  However,
       // we cannot initialize it with _ as that causes ambiguity between
       // Matcher's copy and move constructor for some argument types.
       extra_matcher_(A<const ArgumentTuple&>()),
       repeated_action_(DoDefault()) {}

 ~TypedExpectation() override {
   // Check the validity of the action count if it hasn't been done
   // yet (for example, if the expectation was never used).
   CheckActionCountIfNotDone();
   for (UntypedActions::const_iterator it = untyped_actions_.begin();
        it != untyped_actions_.end(); ++it) {
     delete static_cast<const Action<F>*>(*it);
   }
 }

 // Implements the .With() clause.
 TypedExpectation& With(const Matcher<const ArgumentTuple&>& m) {
   if (last_clause_ == kWith) {
     ExpectSpecProperty(false,
                        ".With() cannot appear "
                        "more than once in an EXPECT_CALL().");
   } else {
     ExpectSpecProperty(last_clause_ < kWith,
                        ".With() must be the first "
                        "clause in an EXPECT_CALL().");
   }
   last_clause_ = kWith;

   extra_matcher_ = m;
   extra_matcher_specified_ = true;
   return *this;
 }

 // Do not rely on this for correctness.
 // This is only for making human-readable test output easier to understand.
 TypedExpectation& Description(std::string name) {
   ExpectationBase::UntypedDescription(std::move(name));
   return *this;
 }

 // Implements the .Times() clause.
 TypedExpectation& Times(const Cardinality& a_cardinality) {
   ExpectationBase::UntypedTimes(a_cardinality);
   return *this;
 }

 // Implements the .Times() clause.
 TypedExpectation& Times(int n) { return Times(Exactly(n)); }

 // Implements the .InSequence() clause.
 TypedExpectation& InSequence(const Sequence& s) {
   ExpectSpecProperty(last_clause_ <= kInSequence,
                      ".InSequence() cannot appear after .After(),"
                      " .WillOnce(), .WillRepeatedly(), or "
                      ".RetiresOnSaturation().");
   last_clause_ = kInSequence;

   s.AddExpectation(GetHandle());
   return *this;
 }
 TypedExpectation& InSequence(const Sequence& s1, const Sequence& s2) {
   return InSequence(s1).InSequence(s2);
 }
 TypedExpectation& InSequence(const Sequence& s1, const Sequence& s2,
                              const Sequence& s3) {
   return InSequence(s1, s2).InSequence(s3);
 }
 TypedExpectation& InSequence(const Sequence& s1, const Sequence& s2,
                              const Sequence& s3, const Sequence& s4) {
   return InSequence(s1, s2, s3).InSequence(s4);
 }
 TypedExpectation& InSequence(const Sequence& s1, const Sequence& s2,
                              const Sequence& s3, const Sequence& s4,
                              const Sequence& s5) {
   return InSequence(s1, s2, s3, s4).InSequence(s5);
 }

 // Implements that .After() clause.
 TypedExpectation& After(const ExpectationSet& s) {
   ExpectSpecProperty(last_clause_ <= kAfter,
                      ".After() cannot appear after .WillOnce(),"
                      " .WillRepeatedly(), or "
                      ".RetiresOnSaturation().");
   last_clause_ = kAfter;

   for (ExpectationSet::const_iterator it = s.begin(); it != s.end(); ++it) {
     immediate_prerequisites_ += *it;
   }
   return *this;
 }
 TypedExpectation& After(const ExpectationSet& s1, const ExpectationSet& s2) {
   return After(s1).After(s2);
 }
 TypedExpectation& After(const ExpectationSet& s1, const ExpectationSet& s2,
                         const ExpectationSet& s3) {
   return After(s1, s2).After(s3);
 }
 TypedExpectation& After(const ExpectationSet& s1, const ExpectationSet& s2,
                         const ExpectationSet& s3, const ExpectationSet& s4) {
   return After(s1, s2, s3).After(s4);
 }
 TypedExpectation& After(const ExpectationSet& s1, const ExpectationSet& s2,
                         const ExpectationSet& s3, const ExpectationSet& s4,
                         const ExpectationSet& s5) {
   return After(s1, s2, s3, s4).After(s5);
 }

 // Preferred, type-safe overload: consume anything that can be directly
 // converted to a OnceAction, except for Action<F> objects themselves.
 TypedExpectation& WillOnce(OnceAction<F> once_action) {
   // Call the overload below, smuggling the OnceAction as a copyable callable.
   // We know this is safe because a WillOnce action will not be called more
   // than once.
   return WillOnce(Action<F>(ActionAdaptor{
       std::make_shared<OnceAction<F>>(std::move(once_action)),
   }));
 }

 // Fallback overload: accept Action<F> objects and those actions that define
 // `operator Action<F>` but not `operator OnceAction<F>`.
 //
 // This is templated in order to cause the overload above to be preferred
 // when the input is convertible to either type.
 template <int&... ExplicitArgumentBarrier, typename = void>
 TypedExpectation& WillOnce(Action<F> action) {
   ExpectSpecProperty(last_clause_ <= kWillOnce,
                      ".WillOnce() cannot appear after "
                      ".WillRepeatedly() or .RetiresOnSaturation().");
   last_clause_ = kWillOnce;

   untyped_actions_.push_back(new Action<F>(std::move(action)));

   if (!cardinality_specified()) {
     set_cardinality(Exactly(static_cast<int>(untyped_actions_.size())));
   }
   return *this;
 }

 // Implements the .WillRepeatedly() clause.
 TypedExpectation& WillRepeatedly(const Action<F>& action) {
   if (last_clause_ == kWillRepeatedly) {
     ExpectSpecProperty(false,
                        ".WillRepeatedly() cannot appear "
                        "more than once in an EXPECT_CALL().");
   } else {
     ExpectSpecProperty(last_clause_ < kWillRepeatedly,
                        ".WillRepeatedly() cannot appear "
                        "after .RetiresOnSaturation().");
   }
   last_clause_ = kWillRepeatedly;
   repeated_action_specified_ = true;

   repeated_action_ = action;
   if (!cardinality_specified()) {
     set_cardinality(AtLeast(static_cast<int>(untyped_actions_.size())));
   }

   // Now that no more action clauses can be specified, we check
   // whether their count makes sense.
   CheckActionCountIfNotDone();
   return *this;
 }

 // Implements the .RetiresOnSaturation() clause.
 TypedExpectation& RetiresOnSaturation() {
   ExpectSpecProperty(last_clause_ < kRetiresOnSaturation,
                      ".RetiresOnSaturation() cannot appear "
                      "more than once.");
   last_clause_ = kRetiresOnSaturation;
   retires_on_saturation_ = true;

   // Now that no more action clauses can be specified, we check
   // whether their count makes sense.
   CheckActionCountIfNotDone();
   return *this;
 }

 // Returns the matchers for the arguments as specified inside the
 // EXPECT_CALL() macro.
 const ArgumentMatcherTuple& matchers() const { return matchers_; }

 // Returns the matcher specified by the .With() clause.
 const Matcher<const ArgumentTuple&>& extra_matcher() const {
   return extra_matcher_;
 }

 // Returns the action specified by the .WillRepeatedly() clause.
 const Action<F>& repeated_action() const { return repeated_action_; }

 // If this mock method has an extra matcher (i.e. .With(matcher)),
 // describes it to the ostream.
 void MaybeDescribeExtraMatcherTo(::std::ostream* os) override {
   if (extra_matcher_specified_) {
     *os << "    Expected args: ";
     extra_matcher_.DescribeTo(os);
     *os << "\n";
   }
 }

private:
 template <typename Function>
 friend class FunctionMocker;

 // An adaptor that turns a OneAction<F> into something compatible with
 // Action<F>. Must be called at most once.
 struct ActionAdaptor {
   std::shared_ptr<OnceAction<R(Args...)>> once_action;

   R operator()(Args&&... args) const {
     return std::move(*once_action).Call(std::forward<Args>(args)...);
   }
 };

 // Returns an Expectation object that references and co-owns this
 // expectation.
 Expectation GetHandle() override { return owner_->GetHandleOf(this); }

 // The following methods will be called only after the EXPECT_CALL()
 // statement finishes and when the current thread holds
 // g_gmock_mutex.

 // Returns true if and only if this expectation matches the given arguments.
 bool Matches(const ArgumentTuple& args) const
     GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
   g_gmock_mutex.AssertHeld();
   return TupleMatches(matchers_, args) && extra_matcher_.Matches(args);
 }

 // Returns true if and only if this expectation should handle the given
 // arguments.
 bool ShouldHandleArguments(const ArgumentTuple& args) const
     GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
   g_gmock_mutex.AssertHeld();

   // In case the action count wasn't checked when the expectation
   // was defined (e.g. if this expectation has no WillRepeatedly()
   // or RetiresOnSaturation() clause), we check it when the
   // expectation is used for the first time.
   CheckActionCountIfNotDone();
   return !is_retired() && AllPrerequisitesAreSatisfied() && Matches(args);
 }

 // Describes the result of matching the arguments against this
 // expectation to the given ostream.
 void ExplainMatchResultTo(const ArgumentTuple& args, ::std::ostream* os) const
     GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
   g_gmock_mutex.AssertHeld();

   if (is_retired()) {
     *os << "         Expected: the expectation is active\n"
         << "           Actual: it is retired\n";
   } else if (!Matches(args)) {
     if (!TupleMatches(matchers_, args)) {
       ExplainMatchFailureTupleTo(matchers_, args, os);
     }
     StringMatchResultListener listener;
     if (!extra_matcher_.MatchAndExplain(args, &listener)) {
       *os << "    Expected args: ";
       extra_matcher_.DescribeTo(os);
       *os << "\n           Actual: don't match";

       internal::PrintIfNotEmpty(listener.str(), os);
       *os << "\n";
     }
   } else if (!AllPrerequisitesAreSatisfied()) {
     *os << "         Expected: all pre-requisites are satisfied\n"
         << "           Actual: the following immediate pre-requisites "
         << "are not satisfied:\n";
     ExpectationSet unsatisfied_prereqs;
     FindUnsatisfiedPrerequisites(&unsatisfied_prereqs);
     int i = 0;
     for (ExpectationSet::const_iterator it = unsatisfied_prereqs.begin();
          it != unsatisfied_prereqs.end(); ++it) {
       it->expectation_base()->DescribeLocationTo(os);
       *os << "pre-requisite #" << i++ << "\n";
     }
     *os << "                   (end of pre-requisites)\n";
   } else {
     // This line is here just for completeness' sake.  It will never
     // be executed as currently the ExplainMatchResultTo() function
     // is called only when the mock function call does NOT match the
     // expectation.
     *os << "The call matches the expectation.\n";
   }
 }

 // Returns the action that should be taken for the current invocation.
 const Action<F>& GetCurrentAction(const FunctionMocker<F>* mocker,
                                   const ArgumentTuple& args) const
     GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
   g_gmock_mutex.AssertHeld();
   const int count = call_count();
   Assert(count >= 1, __FILE__, __LINE__,
          "call_count() is <= 0 when GetCurrentAction() is "
          "called - this should never happen.");

   const int action_count = static_cast<int>(untyped_actions_.size());
   if (action_count > 0 && !repeated_action_specified_ &&
       count > action_count) {
     // If there is at least one WillOnce() and no WillRepeatedly(),
     // we warn the user when the WillOnce() clauses ran out.
     ::std::stringstream ss;
     DescribeLocationTo(&ss);
     ss << "Actions ran out in " << source_text() << "...\n"
        << "Called " << count << " times, but only " << action_count
        << " WillOnce()" << (action_count == 1 ? " is" : "s are")
        << " specified - ";
     mocker->DescribeDefaultActionTo(args, &ss);
     Log(kWarning, ss.str(), 1);
   }

   return count <= action_count
              ? *static_cast<const Action<F>*>(
                    untyped_actions_[static_cast<size_t>(count - 1)])
              : repeated_action();
 }

 // Given the arguments of a mock function call, if the call will
 // over-saturate this expectation, returns the default action;
 // otherwise, returns the next action in this expectation.  Also
 // describes *what* happened to 'what', and explains *why* Google
 // Mock does it to 'why'.  This method is not const as it calls
 // IncrementCallCount().  A return value of NULL means the default
 // action.
 const Action<F>* GetActionForArguments(const FunctionMocker<F>* mocker,
                                        const ArgumentTuple& args,
                                        ::std::ostream* what,
                                        ::std::ostream* why)
     GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
   g_gmock_mutex.AssertHeld();
   const ::std::string& expectation_description = GetDescription();
   if (IsSaturated()) {
     // We have an excessive call.
     IncrementCallCount();
     *what << "Mock function ";
     if (!expectation_description.empty()) {
       *what << "\"" << expectation_description << "\" ";
     }
     *what << "called more times than expected - ";
     mocker->DescribeDefaultActionTo(args, what);
     DescribeCallCountTo(why);

     return nullptr;
   }

   IncrementCallCount();
   RetireAllPreRequisites();

   if (retires_on_saturation_ && IsSaturated()) {
     Retire();
   }

   // Must be done after IncrementCount()!
   *what << "Mock function ";
   if (!expectation_description.empty()) {
     *what << "\"" << expectation_description << "\" ";
   }
   *what << "call matches " << source_text() << "...\n";
   return &(GetCurrentAction(mocker, args));
 }

 // All the fields below won't change once the EXPECT_CALL()
 // statement finishes.
 FunctionMocker<F>* const owner_;
 ArgumentMatcherTuple matchers_;
 Matcher<const ArgumentTuple&> extra_matcher_;
 Action<F> repeated_action_;

 TypedExpectation(const TypedExpectation&) = delete;
 TypedExpectation& operator=(const TypedExpectation&) = delete;
};  // class TypedExpectation

// A MockSpec object is used by ON_CALL() or EXPECT_CALL() for
// specifying the default behavior of, or expectation on, a mock
// function.

// Note: class MockSpec really belongs to the ::testing namespace.
// However if we define it in ::testing, MSVC will complain when
// classes in ::testing::internal declare it as a friend class
// template.  To workaround this compiler bug, we define MockSpec in
// ::testing::internal and import it into ::testing.

// Logs a message including file and line number information.
GTEST_API_ void LogWithLocation(testing::internal::LogSeverity severity,
                               const char* file, int line,
                               const std::string& message);

template <typename F>
class MockSpec {
public:
 typedef typename internal::Function<F>::ArgumentTuple ArgumentTuple;
 typedef
     typename internal::Function<F>::ArgumentMatcherTuple ArgumentMatcherTuple;

 // Constructs a MockSpec object, given the function mocker object
 // that the spec is associated with.
 MockSpec(internal::FunctionMocker<F>* function_mocker,
          const ArgumentMatcherTuple& matchers)
     : function_mocker_(function_mocker), matchers_(matchers) {}

 // Adds a new default action spec to the function mocker and returns
 // the newly created spec.
 internal::OnCallSpec<F>& InternalDefaultActionSetAt(const char* file,
                                                     int line, const char* obj,
                                                     const char* call) {
   LogWithLocation(internal::kInfo, file, line,
                   std::string("ON_CALL(") + obj + ", " + call + ") invoked");
   return function_mocker_->AddNewOnCallSpec(file, line, matchers_);
 }

 // Adds a new expectation spec to the function mocker and returns
 // the newly created spec.
 internal::TypedExpectation<F>& InternalExpectedAt(const char* file, int line,
                                                   const char* obj,
                                                   const char* call) {
   const std::string source_text(std::string("EXPECT_CALL(") + obj + ", " +
                                 call + ")");
   LogWithLocation(internal::kInfo, file, line, source_text + " invoked");
   return function_mocker_->AddNewExpectation(file, line, source_text,
                                              matchers_);
 }

 // This operator overload is used to swallow the superfluous parameter list
 // introduced by the ON/EXPECT_CALL macros. See the macro comments for more
 // explanation.
 MockSpec<F>& operator()(const internal::WithoutMatchers&, void* const) {
   return *this;
 }

private:
 template <typename Function>
 friend class internal::FunctionMocker;

 // The function mocker that owns this spec.
 internal::FunctionMocker<F>* const function_mocker_;
 // The argument matchers specified in the spec.
 ArgumentMatcherTuple matchers_;
};  // class MockSpec

// Wrapper type for generically holding an ordinary value or lvalue reference.
// If T is not a reference type, it must be copyable or movable.
// ReferenceOrValueWrapper<T> is movable, and will also be copyable unless
// T is a move-only value type (which means that it will always be copyable
// if the current platform does not support move semantics).
//
// The primary template defines handling for values, but function header
// comments describe the contract for the whole template (including
// specializations).
template <typename T>
class ReferenceOrValueWrapper {
public:
 // Constructs a wrapper from the given value/reference.
 explicit ReferenceOrValueWrapper(T value) : value_(std::move(value)) {}

 // Unwraps and returns the underlying value/reference, exactly as
 // originally passed. The behavior of calling this more than once on
 // the same object is unspecified.
 T Unwrap() { return std::move(value_); }

 // Provides nondestructive access to the underlying value/reference.
 // Always returns a const reference (more precisely,
 // const std::add_lvalue_reference<T>::type). The behavior of calling this
 // after calling Unwrap on the same object is unspecified.
 const T& Peek() const { return value_; }

private:
 T value_;
};

// Specialization for lvalue reference types. See primary template
// for documentation.
template <typename T>
class ReferenceOrValueWrapper<T&> {
public:
 // Workaround for debatable pass-by-reference lint warning (c-library-team
 // policy precludes NOLINT in this context)
 typedef T& reference;
 explicit ReferenceOrValueWrapper(reference ref) : value_ptr_(&ref) {}
 T& Unwrap() { return *value_ptr_; }
 const T& Peek() const { return *value_ptr_; }

private:
 T* value_ptr_;
};

// Prints the held value as an action's result to os.
template <typename T>
void PrintAsActionResult(const T& result, std::ostream& os) {
 os << "\n          Returns: ";
 // T may be a reference type, so we don't use UniversalPrint().
 UniversalPrinter<T>::Print(result, &os);
}

// Reports an uninteresting call (whose description is in msg) in the
// manner specified by 'reaction'.
GTEST_API_ void ReportUninterestingCall(CallReaction reaction,
                                       const std::string& msg);

// A generic RAII type that runs a user-provided function in its destructor.
class Cleanup final {
public:
 explicit Cleanup(std::function<void()> f) : f_(std::move(f)) {}
 ~Cleanup() { f_(); }

private:
 std::function<void()> f_;
};

struct UntypedFunctionMockerBase::UninterestingCallCleanupHandler {
 CallReaction reaction;
 std::stringstream& ss;

 ~UninterestingCallCleanupHandler() {
   ReportUninterestingCall(reaction, ss.str());
 }
};

struct UntypedFunctionMockerBase::FailureCleanupHandler {
 std::stringstream& ss;
 std::stringstream& why;
 std::stringstream& loc;
 const ExpectationBase* untyped_expectation;
 bool found;
 bool is_excessive;

 ~FailureCleanupHandler() {
   ss << "\n" << why.str();

   if (!found) {
     // No expectation matches this call - reports a failure.
     Expect(false, nullptr, -1, ss.str());
   } else if (is_excessive) {
     // We had an upper-bound violation and the failure message is in ss.
     Expect(false, untyped_expectation->file(), untyped_expectation->line(),
            ss.str());
   } else {
     // We had an expected call and the matching expectation is
     // described in ss.
     Log(kInfo, loc.str() + ss.str(), 2);
   }
 }
};

template <typename F>
class FunctionMocker;

template <typename R, typename... Args>
class FunctionMocker<R(Args...)> final : public UntypedFunctionMockerBase {
 using F = R(Args...);

public:
 using Result = R;
 using ArgumentTuple = std::tuple<Args...>;
 using ArgumentMatcherTuple = std::tuple<Matcher<Args>...>;

 FunctionMocker() = default;

 // There is no generally useful and implementable semantics of
 // copying a mock object, so copying a mock is usually a user error.
 // Thus we disallow copying function mockers.  If the user really
 // wants to copy a mock object, they should implement their own copy
 // operation, for example:
 //
 //   class MockFoo : public Foo {
 //    public:
 //     // Defines a copy constructor explicitly.
 //     MockFoo(const MockFoo& src) {}
 //     ...
 //   };
 FunctionMocker(const FunctionMocker&) = delete;
 FunctionMocker& operator=(const FunctionMocker&) = delete;

 // The destructor verifies that all expectations on this mock
 // function have been satisfied.  If not, it will report Google Test
 // non-fatal failures for the violations.
 ~FunctionMocker() override GTEST_LOCK_EXCLUDED_(g_gmock_mutex) {
   MutexLock l(&g_gmock_mutex);
   VerifyAndClearExpectationsLocked();
   Mock::UnregisterLocked(this);
   ClearDefaultActionsLocked();
 }

 // Returns the ON_CALL spec that matches this mock function with the
 // given arguments; returns NULL if no matching ON_CALL is found.
 // L = *
 const OnCallSpec<F>* FindOnCallSpec(const ArgumentTuple& args) const {
   for (UntypedOnCallSpecs::const_reverse_iterator it =
            untyped_on_call_specs_.rbegin();
        it != untyped_on_call_specs_.rend(); ++it) {
     const OnCallSpec<F>* spec = static_cast<const OnCallSpec<F>*>(*it);
     if (spec->Matches(args)) return spec;
   }

   return nullptr;
 }

 // Performs the default action of this mock function on the given
 // arguments and returns the result. Asserts (or throws if
 // exceptions are enabled) with a helpful call description if there
 // is no valid return value. This method doesn't depend on the
 // mutable state of this object, and thus can be called concurrently
 // without locking.
 // L = *
 Result PerformDefaultAction(ArgumentTuple&& args,
                             const std::string& call_description) const {
   const OnCallSpec<F>* const spec = this->FindOnCallSpec(args);
   if (spec != nullptr) {
     return spec->GetAction().Perform(std::move(args));
   }
   const std::string message =
       call_description +
       "\n    The mock function has no default action "
       "set, and its return type has no default value set.";
#if GTEST_HAS_EXCEPTIONS
   if (!DefaultValue<Result>::Exists()) {
     throw std::runtime_error(message);
   }
#else
   Assert(DefaultValue<Result>::Exists(), "", -1, message);
#endif
   return DefaultValue<Result>::Get();
 }

 // Implements UntypedFunctionMockerBase::ClearDefaultActionsLocked():
 // clears the ON_CALL()s set on this mock function.
 void ClearDefaultActionsLocked() override
     GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
   g_gmock_mutex.AssertHeld();

   // Deleting our default actions may trigger other mock objects to be
   // deleted, for example if an action contains a reference counted smart
   // pointer to that mock object, and that is the last reference. So if we
   // delete our actions within the context of the global mutex we may deadlock
   // when this method is called again. Instead, make a copy of the set of
   // actions to delete, clear our set within the mutex, and then delete the
   // actions outside of the mutex.
   UntypedOnCallSpecs specs_to_delete;
   untyped_on_call_specs_.swap(specs_to_delete);

   g_gmock_mutex.unlock();
   for (UntypedOnCallSpecs::const_iterator it = specs_to_delete.begin();
        it != specs_to_delete.end(); ++it) {
     delete static_cast<const OnCallSpec<F>*>(*it);
   }

   // Lock the mutex again, since the caller expects it to be locked when we
   // return.
   g_gmock_mutex.lock();
 }

 // Returns the result of invoking this mock function with the given
 // arguments.  This function can be safely called from multiple
 // threads concurrently.
 Result Invoke(Args... args) GTEST_LOCK_EXCLUDED_(g_gmock_mutex) {
   return InvokeWith(ArgumentTuple(std::forward<Args>(args)...));
 }

 MockSpec<F> With(Matcher<Args>... m) {
   return MockSpec<F>(this, ::std::make_tuple(std::move(m)...));
 }

protected:
 template <typename Function>
 friend class MockSpec;

 // Adds and returns a default action spec for this mock function.
 OnCallSpec<F>& AddNewOnCallSpec(const char* file, int line,
                                 const ArgumentMatcherTuple& m)
     GTEST_LOCK_EXCLUDED_(g_gmock_mutex) {
   Mock::RegisterUseByOnCallOrExpectCall(MockObject(), file, line);
   OnCallSpec<F>* const on_call_spec = new OnCallSpec<F>(file, line, m);
   untyped_on_call_specs_.push_back(on_call_spec);
   return *on_call_spec;
 }

 // Adds and returns an expectation spec for this mock function.
 TypedExpectation<F>& AddNewExpectation(const char* file, int line,
                                        const std::string& source_text,
                                        const ArgumentMatcherTuple& m)
     GTEST_LOCK_EXCLUDED_(g_gmock_mutex) {
   Mock::RegisterUseByOnCallOrExpectCall(MockObject(), file, line);
   TypedExpectation<F>* const expectation =
       new TypedExpectation<F>(this, file, line, source_text, m);
   const std::shared_ptr<ExpectationBase> untyped_expectation(expectation);
   // See the definition of untyped_expectations_ for why access to
   // it is unprotected here.
   untyped_expectations_.push_back(untyped_expectation);

   // Adds this expectation into the implicit sequence if there is one.
   Sequence* const implicit_sequence = g_gmock_implicit_sequence.get();
   if (implicit_sequence != nullptr) {
     implicit_sequence->AddExpectation(Expectation(untyped_expectation));
   }

   return *expectation;
 }

private:
 template <typename Func>
 friend class TypedExpectation;

 // Some utilities needed for implementing UntypedInvokeWith().

 // Describes what default action will be performed for the given
 // arguments.
 // L = *
 void DescribeDefaultActionTo(const ArgumentTuple& args,
                              ::std::ostream* os) const {
   const OnCallSpec<F>* const spec = FindOnCallSpec(args);

   if (spec == nullptr) {
     *os << (std::is_void<Result>::value ? "returning directly.\n"
                                         : "returning default value.\n");
   } else {
     *os << "taking default action specified at:\n"
         << FormatFileLocation(spec->file(), spec->line()) << "\n";
   }
 }

 // Writes a message that the call is uninteresting (i.e. neither
 // explicitly expected nor explicitly unexpected) to the given
 // ostream.
 void UntypedDescribeUninterestingCall(const void* untyped_args,
                                       ::std::ostream* os) const override
     GTEST_LOCK_EXCLUDED_(g_gmock_mutex) {
   const ArgumentTuple& args =
       *static_cast<const ArgumentTuple*>(untyped_args);
   *os << "Uninteresting mock function call - ";
   DescribeDefaultActionTo(args, os);
   *os << "    Function call: " << Name();
   UniversalPrint(args, os);
 }

 // Returns the expectation that matches the given function arguments
 // (or NULL is there's no match); when a match is found,
 // untyped_action is set to point to the action that should be
 // performed (or NULL if the action is "do default"), and
 // is_excessive is modified to indicate whether the call exceeds the
 // expected number.
 //
 // Critical section: We must find the matching expectation and the
 // corresponding action that needs to be taken in an ATOMIC
 // transaction.  Otherwise another thread may call this mock
 // method in the middle and mess up the state.
 //
 // However, performing the action has to be left out of the critical
 // section.  The reason is that we have no control on what the
 // action does (it can invoke an arbitrary user function or even a
 // mock function) and excessive locking could cause a dead lock.
 const ExpectationBase* UntypedFindMatchingExpectation(
     const void* untyped_args, const void** untyped_action, bool* is_excessive,
     ::std::ostream* what, ::std::ostream* why) override
     GTEST_LOCK_EXCLUDED_(g_gmock_mutex) {
   const ArgumentTuple& args =
       *static_cast<const ArgumentTuple*>(untyped_args);
   MutexLock l(&g_gmock_mutex);
   TypedExpectation<F>* exp = this->FindMatchingExpectationLocked(args);
   if (exp == nullptr) {  // A match wasn't found.
     this->FormatUnexpectedCallMessageLocked(args, what, why);
     return nullptr;
   }

   // This line must be done before calling GetActionForArguments(),
   // which will increment the call count for *exp and thus affect
   // its saturation status.
   *is_excessive = exp->IsSaturated();
   const Action<F>* action = exp->GetActionForArguments(this, args, what, why);
   if (action != nullptr && action->IsDoDefault())
     action = nullptr;  // Normalize "do default" to NULL.
   *untyped_action = action;
   return exp;
 }

 // Prints the given function arguments to the ostream.
 void UntypedPrintArgs(const void* untyped_args,
                       ::std::ostream* os) const override {
   const ArgumentTuple& args =
       *static_cast<const ArgumentTuple*>(untyped_args);
   UniversalPrint(args, os);
 }

 // Returns the expectation that matches the arguments, or NULL if no
 // expectation matches them.
 TypedExpectation<F>* FindMatchingExpectationLocked(const ArgumentTuple& args)
     const GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
   g_gmock_mutex.AssertHeld();
   // See the definition of untyped_expectations_ for why access to
   // it is unprotected here.
   for (typename UntypedExpectations::const_reverse_iterator it =
            untyped_expectations_.rbegin();
        it != untyped_expectations_.rend(); ++it) {
     TypedExpectation<F>* const exp =
         static_cast<TypedExpectation<F>*>(it->get());
     if (exp->ShouldHandleArguments(args)) {
       return exp;
     }
   }
   return nullptr;
 }

 // Returns a message that the arguments don't match any expectation.
 void FormatUnexpectedCallMessageLocked(const ArgumentTuple& args,
                                        ::std::ostream* os,
                                        ::std::ostream* why) const
     GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
   g_gmock_mutex.AssertHeld();
   *os << "\nUnexpected mock function call - ";
   DescribeDefaultActionTo(args, os);
   PrintTriedExpectationsLocked(args, why);
 }

 // Prints a list of expectations that have been tried against the
 // current mock function call.
 void PrintTriedExpectationsLocked(const ArgumentTuple& args,
                                   ::std::ostream* why) const
     GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
   g_gmock_mutex.AssertHeld();
   const size_t count = untyped_expectations_.size();
   *why << "Google Mock tried the following " << count << " "
        << (count == 1 ? "expectation, but it didn't match"
                       : "expectations, but none matched")
        << ":\n";
   for (size_t i = 0; i < count; i++) {
     TypedExpectation<F>* const expectation =
         static_cast<TypedExpectation<F>*>(untyped_expectations_[i].get());
     *why << "\n";
     expectation->DescribeLocationTo(why);
     if (count > 1) {
       *why << "tried expectation #" << i << ": ";
     }
     *why << expectation->source_text() << "...\n";
     expectation->ExplainMatchResultTo(args, why);
     expectation->DescribeCallCountTo(why);
   }
 }

 // Performs the given action (or the default if it's null) with the given
 // arguments and returns the action's result.
 // L = *
 R PerformAction(const void* untyped_action, ArgumentTuple&& args,
                 const std::string& call_description) const {
   if (untyped_action == nullptr) {
     return PerformDefaultAction(std::move(args), call_description);
   }

   // Make a copy of the action before performing it, in case the
   // action deletes the mock object (and thus deletes itself).
   const Action<F> action = *static_cast<const Action<F>*>(untyped_action);
   return action.Perform(std::move(args));
 }

 // Is it possible to store an object of the supplied type in a local variable
 // for the sake of printing it, then return it on to the caller?
 template <typename T>
 using can_print_result = internal::conjunction<
     // void can't be stored as an object (and we also don't need to print it).
     internal::negation<std::is_void<T>>,
     // Non-moveable types can't be returned on to the user, so there's no way
     // for us to intercept and print them.
     std::is_move_constructible<T>>;

 // Perform the supplied action, printing the result to os.
 template <typename T = R,
           typename std::enable_if<can_print_result<T>::value, int>::type = 0>
 R PerformActionAndPrintResult(const void* const untyped_action,
                               ArgumentTuple&& args,
                               const std::string& call_description,
                               std::ostream& os) {
   R result = PerformAction(untyped_action, std::move(args), call_description);

   PrintAsActionResult(result, os);
   return std::forward<R>(result);
 }

 // An overload for when it's not possible to print the result. In this case we
 // simply perform the action.
 template <typename T = R,
           typename std::enable_if<
               internal::negation<can_print_result<T>>::value, int>::type = 0>
 R PerformActionAndPrintResult(const void* const untyped_action,
                               ArgumentTuple&& args,
                               const std::string& call_description,
                               std::ostream&) {
   return PerformAction(untyped_action, std::move(args), call_description);
 }

 // Returns the result of invoking this mock function with the given
 // arguments. This function can be safely called from multiple
 // threads concurrently.
 R InvokeWith(ArgumentTuple&& args) GTEST_LOCK_EXCLUDED_(g_gmock_mutex);
};  // class FunctionMocker

// Calculates the result of invoking this mock function with the given
// arguments, prints it, and returns it.
template <typename R, typename... Args>
R FunctionMocker<R(Args...)>::InvokeWith(ArgumentTuple&& args)
   GTEST_LOCK_EXCLUDED_(g_gmock_mutex) {
 // See the definition of untyped_expectations_ for why access to it
 // is unprotected here.
 if (untyped_expectations_.size() == 0) {
   // No expectation is set on this mock method - we have an
   // uninteresting call.

   // We must get Google Mock's reaction on uninteresting calls
   // made on this mock object BEFORE performing the action,
   // because the action may DELETE the mock object and make the
   // following expression meaningless.
   const CallReaction reaction =
       Mock::GetReactionOnUninterestingCalls(MockObject());

   // True if and only if we need to print this call's arguments and return
   // value.  This definition must be kept in sync with
   // the behavior of ReportUninterestingCall().
   const bool need_to_report_uninteresting_call =
       // If the user allows this uninteresting call, we print it
       // only when they want informational messages.
       reaction == kAllow ? LogIsVisible(kInfo) :
                          // If the user wants this to be a warning, we print
                          // it only when they want to see warnings.
           reaction == kWarn
           ? LogIsVisible(kWarning)
           :
           // Otherwise, the user wants this to be an error, and we
           // should always print detailed information in the error.
           true;

   if (!need_to_report_uninteresting_call) {
     // Perform the action without printing the call information.
     return this->PerformDefaultAction(
         std::move(args), "Function call: " + std::string(Name()));
   }

   // Warns about the uninteresting call.
   ::std::stringstream ss;
   this->UntypedDescribeUninterestingCall(&args, &ss);

   // Perform the action, print the result, and then report the uninteresting
   // call.
   //
   // We use RAII to do the latter in case R is void or a non-moveable type. In
   // either case we can't assign it to a local variable.
   //
   // Note that std::bind() is essential here.
   // We *don't* use any local callback types (like lambdas).
   // Doing so slows down compilation dramatically because the *constructor* of
   // std::function<T> is re-instantiated with different template
   // parameters each time.
   const UninterestingCallCleanupHandler report_uninteresting_call = {reaction,
                                                                      ss};

   return PerformActionAndPrintResult(nullptr, std::move(args), ss.str(), ss);
 }

 bool is_excessive = false;
 ::std::stringstream ss;
 ::std::stringstream why;
 ::std::stringstream loc;
 const void* untyped_action = nullptr;

 // The UntypedFindMatchingExpectation() function acquires and
 // releases g_gmock_mutex.

 const ExpectationBase* const untyped_expectation =
     this->UntypedFindMatchingExpectation(&args, &untyped_action,
                                          &is_excessive, &ss, &why);
 const bool found = untyped_expectation != nullptr;

 // True if and only if we need to print the call's arguments
 // and return value.
 // This definition must be kept in sync with the uses of Expect()
 // and Log() in this function.
 const bool need_to_report_call =
     !found || is_excessive || LogIsVisible(kInfo);
 if (!need_to_report_call) {
   // Perform the action without printing the call information.
   return PerformAction(untyped_action, std::move(args), "");
 }

 ss << "    Function call: " << Name();
 this->UntypedPrintArgs(&args, &ss);

 // In case the action deletes a piece of the expectation, we
 // generate the message beforehand.
 if (found && !is_excessive) {
   untyped_expectation->DescribeLocationTo(&loc);
 }

 // Perform the action, print the result, and then fail or log in whatever way
 // is appropriate.
 //
 // We use RAII to do the latter in case R is void or a non-moveable type. In
 // either case we can't assign it to a local variable.
 //
 // Note that we *don't* use any local callback types (like lambdas) here.
 // Doing so slows down compilation dramatically because the *constructor* of
 // std::function<T> is re-instantiated with different template
 // parameters each time.
 const FailureCleanupHandler handle_failures = {
     ss, why, loc, untyped_expectation, found, is_excessive};

 return PerformActionAndPrintResult(untyped_action, std::move(args), ss.str(),
                                    ss);
}

}  // namespace internal

namespace internal {

template <typename F>
class MockFunction;

template <typename R, typename... Args>
class MockFunction<R(Args...)> {
public:
 MockFunction(const MockFunction&) = delete;
 MockFunction& operator=(const MockFunction&) = delete;

 std::function<R(Args...)> AsStdFunction() {
   return [this](Args... args) -> R {
     return this->Call(std::forward<Args>(args)...);
   };
 }

 // Implementation detail: the expansion of the MOCK_METHOD macro.
 R Call(Args... args) {
   mock_.SetOwnerAndName(this, "Call");
   return mock_.Invoke(std::forward<Args>(args)...);
 }

 MockSpec<R(Args...)> gmock_Call(Matcher<Args>... m) {
   mock_.RegisterOwner(this);
   return mock_.With(std::move(m)...);
 }

 MockSpec<R(Args...)> gmock_Call(const WithoutMatchers&, R (*)(Args...)) {
   return this->gmock_Call(::testing::A<Args>()...);
 }

protected:
 MockFunction() = default;
 ~MockFunction() = default;

private:
 FunctionMocker<R(Args...)> mock_;
};

/*
The SignatureOf<F> struct is a meta-function returning function signature
corresponding to the provided F argument.

It makes use of MockFunction easier by allowing it to accept more F arguments
than just function signatures.

Specializations provided here cover a signature type itself and any template
that can be parameterized with a signature, including std::function and
boost::function.
*/

template <typename F, typename = void>
struct SignatureOf;

template <typename R, typename... Args>
struct SignatureOf<R(Args...)> {
 using type = R(Args...);
};

template <template <typename> class C, typename F>
struct SignatureOf<C<F>,
                  typename std::enable_if<std::is_function<F>::value>::type>
   : SignatureOf<F> {};

template <typename F>
using SignatureOfT = typename SignatureOf<F>::type;

}  // namespace internal

// A MockFunction<F> type has one mock method whose type is
// internal::SignatureOfT<F>.  It is useful when you just want your
// test code to emit some messages and have Google Mock verify the
// right messages are sent (and perhaps at the right times).  For
// example, if you are exercising code:
//
//   Foo(1);
//   Foo(2);
//   Foo(3);
//
// and want to verify that Foo(1) and Foo(3) both invoke
// mock.Bar("a"), but Foo(2) doesn't invoke anything, you can write:
//
// TEST(FooTest, InvokesBarCorrectly) {
//   MyMock mock;
//   MockFunction<void(string check_point_name)> check;
//   {
//     InSequence s;
//
//     EXPECT_CALL(mock, Bar("a"));
//     EXPECT_CALL(check, Call("1"));
//     EXPECT_CALL(check, Call("2"));
//     EXPECT_CALL(mock, Bar("a"));
//   }
//   Foo(1);
//   check.Call("1");
//   Foo(2);
//   check.Call("2");
//   Foo(3);
// }
//
// The expectation spec says that the first Bar("a") must happen
// before check point "1", the second Bar("a") must happen after check
// point "2", and nothing should happen between the two check
// points. The explicit check points make it easy to tell which
// Bar("a") is called by which call to Foo().
//
// MockFunction<F> can also be used to exercise code that accepts
// std::function<internal::SignatureOfT<F>> callbacks. To do so, use
// AsStdFunction() method to create std::function proxy forwarding to
// original object's Call. Example:
//
// TEST(FooTest, RunsCallbackWithBarArgument) {
//   MockFunction<int(string)> callback;
//   EXPECT_CALL(callback, Call("bar")).WillOnce(Return(1));
//   Foo(callback.AsStdFunction());
// }
//
// The internal::SignatureOfT<F> indirection allows to use other types
// than just function signature type. This is typically useful when
// providing a mock for a predefined std::function type. Example:
//
// using FilterPredicate = std::function<bool(string)>;
// void MyFilterAlgorithm(FilterPredicate predicate);
//
// TEST(FooTest, FilterPredicateAlwaysAccepts) {
//   MockFunction<FilterPredicate> predicateMock;
//   EXPECT_CALL(predicateMock, Call(_)).WillRepeatedly(Return(true));
//   MyFilterAlgorithm(predicateMock.AsStdFunction());
// }
template <typename F>
class MockFunction : public internal::MockFunction<internal::SignatureOfT<F>> {
 using Base = internal::MockFunction<internal::SignatureOfT<F>>;

public:
 using Base::Base;
};

// The style guide prohibits "using" statements in a namespace scope
// inside a header file.  However, the MockSpec class template is
// meant to be defined in the ::testing namespace.  The following line
// is just a trick for working around a bug in MSVC 8.0, which cannot
// handle it if we define MockSpec in ::testing.
using internal::MockSpec;

// Const(x) is a convenient function for obtaining a const reference
// to x.  This is useful for setting expectations on an overloaded
// const mock method, e.g.
//
//   class MockFoo : public FooInterface {
//    public:
//     MOCK_METHOD0(Bar, int());
//     MOCK_CONST_METHOD0(Bar, int&());
//   };
//
//   MockFoo foo;
//   // Expects a call to non-const MockFoo::Bar().
//   EXPECT_CALL(foo, Bar());
//   // Expects a call to const MockFoo::Bar().
//   EXPECT_CALL(Const(foo), Bar());
template <typename T>
inline const T& Const(const T& x) {
 return x;
}

// Constructs an Expectation object that references and co-owns exp.
inline Expectation::Expectation(internal::ExpectationBase& exp)  // NOLINT
   : expectation_base_(exp.GetHandle().expectation_base()) {}

}  // namespace testing

GTEST_DISABLE_MSC_WARNINGS_POP_()  //  4251

// Implementation for ON_CALL and EXPECT_CALL macros. A separate macro is
// required to avoid compile errors when the name of the method used in call is
// a result of macro expansion. See CompilesWithMethodNameExpandedFromMacro
// tests in internal/gmock-spec-builders_test.cc for more details.
//
// This macro supports statements both with and without parameter matchers. If
// the parameter list is omitted, gMock will accept any parameters, which allows
// tests to be written that don't need to encode the number of method
// parameter. This technique may only be used for non-overloaded methods.
//
//   // These are the same:
//   ON_CALL(mock, NoArgsMethod()).WillByDefault(...);
//   ON_CALL(mock, NoArgsMethod).WillByDefault(...);
//
//   // As are these:
//   ON_CALL(mock, TwoArgsMethod(_, _)).WillByDefault(...);
//   ON_CALL(mock, TwoArgsMethod).WillByDefault(...);
//
//   // Can also specify args if you want, of course:
//   ON_CALL(mock, TwoArgsMethod(_, 45)).WillByDefault(...);
//
//   // Overloads work as long as you specify parameters:
//   ON_CALL(mock, OverloadedMethod(_)).WillByDefault(...);
//   ON_CALL(mock, OverloadedMethod(_, _)).WillByDefault(...);
//
//   // Oops! Which overload did you want?
//   ON_CALL(mock, OverloadedMethod).WillByDefault(...);
//     => ERROR: call to member function 'gmock_OverloadedMethod' is ambiguous
//
// How this works: The mock class uses two overloads of the gmock_Method
// expectation setter method plus an operator() overload on the MockSpec object.
// In the matcher list form, the macro expands to:
//
//   // This statement:
//   ON_CALL(mock, TwoArgsMethod(_, 45))...
//
//   // ...expands to:
//   mock.gmock_TwoArgsMethod(_, 45)(WithoutMatchers(), nullptr)...
//   |-------------v---------------||------------v-------------|
//       invokes first overload        swallowed by operator()
//
//   // ...which is essentially:
//   mock.gmock_TwoArgsMethod(_, 45)...
//
// Whereas the form without a matcher list:
//
//   // This statement:
//   ON_CALL(mock, TwoArgsMethod)...
//
//   // ...expands to:
//   mock.gmock_TwoArgsMethod(WithoutMatchers(), nullptr)...
//   |-----------------------v--------------------------|
//                 invokes second overload
//
//   // ...which is essentially:
//   mock.gmock_TwoArgsMethod(_, _)...
//
// The WithoutMatchers() argument is used to disambiguate overloads and to
// block the caller from accidentally invoking the second overload directly. The
// second argument is an internal type derived from the method signature. The
// failure to disambiguate two overloads of this method in the ON_CALL statement
// is how we block callers from setting expectations on overloaded methods.
#define GMOCK_ON_CALL_IMPL_(mock_expr, Setter, call)                    \
 ((mock_expr).gmock_##call)(::testing::internal::GetWithoutMatchers(), \
                            nullptr)                                   \
     .Setter(__FILE__, __LINE__, #mock_expr, #call)

#define ON_CALL(obj, call) \
 GMOCK_ON_CALL_IMPL_(obj, InternalDefaultActionSetAt, call)

#define EXPECT_CALL(obj, call) \
 GMOCK_ON_CALL_IMPL_(obj, InternalExpectedAt, call)

#endif  // GOOGLEMOCK_INCLUDE_GMOCK_GMOCK_SPEC_BUILDERS_H_