// Copyright 2008 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.


// Type and function utilities for implementing parameterized tests.

#ifndef GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_PARAM_UTIL_H_
#define GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_PARAM_UTIL_H_

#include <ctype.h>

#include <cassert>
#include <iterator>
#include <memory>
#include <set>
#include <tuple>
#include <type_traits>
#include <utility>
#include <vector>

#include "gtest/internal/gtest-internal.h"
#include "gtest/internal/gtest-port.h"
#include "gtest/gtest-printers.h"
#include "gtest/gtest-test-part.h"

namespace testing {
// Input to a parameterized test name generator, describing a test parameter.
// Consists of the parameter value and the integer parameter index.
template <class ParamType>
struct TestParamInfo {
  TestParamInfo(const ParamType& a_param, size_t an_index) :
    param(a_param),
    index(an_index) {}
  ParamType param;
  size_t index;
};

// A builtin parameterized test name generator which returns the result of
// testing::PrintToString.
struct PrintToStringParamName {
  template <class ParamType>
  std::string operator()(const TestParamInfo<ParamType>& info) const {
    return PrintToString(info.param);
  }
};

namespace internal {

// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
// Utility Functions

// Outputs a message explaining invalid registration of different
// fixture class for the same test suite. This may happen when
// TEST_P macro is used to define two tests with the same name
// but in different namespaces.
GTEST_API_ void ReportInvalidTestSuiteType(const char* test_suite_name,
                                           CodeLocation code_location);

template <typename> class ParamGeneratorInterface;
template <typename> class ParamGenerator;

// Interface for iterating over elements provided by an implementation
// of ParamGeneratorInterface<T>.
template <typename T>
class ParamIteratorInterface {
 public:
  virtual ~ParamIteratorInterface() {}
  // A pointer to the base generator instance.
  // Used only for the purposes of iterator comparison
  // to make sure that two iterators belong to the same generator.
  virtual const ParamGeneratorInterface<T>* BaseGenerator() const = 0;
  // Advances iterator to point to the next element
  // provided by the generator. The caller is responsible
  // for not calling Advance() on an iterator equal to
  // BaseGenerator()->End().
  virtual void Advance() = 0;
  // Clones the iterator object. Used for implementing copy semantics
  // of ParamIterator<T>.
  virtual ParamIteratorInterface* Clone() const = 0;
  // Dereferences the current iterator and provides (read-only) access
  // to the pointed value. It is the caller's responsibility not to call
  // Current() on an iterator equal to BaseGenerator()->End().
  // Used for implementing ParamGenerator<T>::operator*().
  virtual const T* Current() const = 0;
  // Determines whether the given iterator and other point to the same
  // element in the sequence generated by the generator.
  // Used for implementing ParamGenerator<T>::operator==().
  virtual bool Equals(const ParamIteratorInterface& other) const = 0;
};

// Class iterating over elements provided by an implementation of
// ParamGeneratorInterface<T>. It wraps ParamIteratorInterface<T>
// and implements the const forward iterator concept.
template <typename T>
class ParamIterator {
 public:
  typedef T value_type;
  typedef const T& reference;
  typedef ptrdiff_t difference_type;

  // ParamIterator assumes ownership of the impl_ pointer.
  ParamIterator(const ParamIterator& other) : impl_(other.impl_->Clone()) {}
  ParamIterator& operator=(const ParamIterator& other) {
    if (this != &other)
      impl_.reset(other.impl_->Clone());
    return *this;
  }

  const T& operator*() const { return *impl_->Current(); }
  const T* operator->() const { return impl_->Current(); }
  // Prefix version of operator++.
  ParamIterator& operator++() {
    impl_->Advance();
    return *this;
  }
  // Postfix version of operator++.
  ParamIterator operator++(int /*unused*/) {
    ParamIteratorInterface<T>* clone = impl_->Clone();
    impl_->Advance();
    return ParamIterator(clone);
  }
  bool operator==(const ParamIterator& other) const {
    return impl_.get() == other.impl_.get() || impl_->Equals(*other.impl_);
  }
  bool operator!=(const ParamIterator& other) const {
    return !(*this == other);
  }

 private:
  friend class ParamGenerator<T>;
  explicit ParamIterator(ParamIteratorInterface<T>* impl) : impl_(impl) {}
  std::unique_ptr<ParamIteratorInterface<T> > impl_;
};

// ParamGeneratorInterface<T> is the binary interface to access generators
// defined in other translation units.
template <typename T>
class ParamGeneratorInterface {
 public:
  typedef T ParamType;

  virtual ~ParamGeneratorInterface() {}

  // Generator interface definition
  virtual ParamIteratorInterface<T>* Begin() const = 0;
  virtual ParamIteratorInterface<T>* End() const = 0;
};

// Wraps ParamGeneratorInterface<T> and provides general generator syntax
// compatible with the STL Container concept.
// This class implements copy initialization semantics and the contained
// ParamGeneratorInterface<T> instance is shared among all copies
// of the original object. This is possible because that instance is immutable.
template<typename T>
class ParamGenerator {
 public:
  typedef ParamIterator<T> iterator;

  explicit ParamGenerator(ParamGeneratorInterface<T>* impl) : impl_(impl) {}
  ParamGenerator(const ParamGenerator& other) : impl_(other.impl_) {}

  ParamGenerator& operator=(const ParamGenerator& other) {
    impl_ = other.impl_;
    return *this;
  }

  iterator begin() const { return iterator(impl_->Begin()); }
  iterator end() const { return iterator(impl_->End()); }

 private:
  std::shared_ptr<const ParamGeneratorInterface<T> > impl_;
};

// Generates values from a range of two comparable values. Can be used to
// generate sequences of user-defined types that implement operator+() and
// operator<().
// This class is used in the Range() function.
template <typename T, typename IncrementT>
class RangeGenerator : public ParamGeneratorInterface<T> {
 public:
  RangeGenerator(T begin, T end, IncrementT step)
      : begin_(begin), end_(end),
        step_(step), end_index_(CalculateEndIndex(begin, end, step)) {}
  ~RangeGenerator() override {}

  ParamIteratorInterface<T>* Begin() const override {
    return new Iterator(this, begin_, 0, step_);
  }
  ParamIteratorInterface<T>* End() const override {
    return new Iterator(this, end_, end_index_, step_);
  }

 private:
  class Iterator : public ParamIteratorInterface<T> {
   public:
    Iterator(const ParamGeneratorInterface<T>* base, T value, int index,
             IncrementT step)
        : base_(base), value_(value), index_(index), step_(step) {}
    ~Iterator() override {}

    const ParamGeneratorInterface<T>* BaseGenerator() const override {
      return base_;
    }
    void Advance() override {
      value_ = static_cast<T>(value_ + step_);
      index_++;
    }
    ParamIteratorInterface<T>* Clone() const override {
      return new Iterator(*this);
    }
    const T* Current() const override { return &value_; }
    bool Equals(const ParamIteratorInterface<T>& other) const override {
      // Having the same base generator guarantees that the other
      // iterator is of the same type and we can downcast.
      GTEST_CHECK_(BaseGenerator() == other.BaseGenerator())
          << "The program attempted to compare iterators "
          << "from different generators." << std::endl;
      const int other_index =
          CheckedDowncastToActualType<const Iterator>(&other)->index_;
      return index_ == other_index;
    }

   private:
    Iterator(const Iterator& other)
        : ParamIteratorInterface<T>(),
          base_(other.base_), value_(other.value_), index_(other.index_),
          step_(other.step_) {}

    // No implementation - assignment is unsupported.
    void operator=(const Iterator& other);

    const ParamGeneratorInterface<T>* const base_;
    T value_;
    int index_;
    const IncrementT step_;
  };  // class RangeGenerator::Iterator

  static int CalculateEndIndex(const T& begin,
                               const T& end,
                               const IncrementT& step) {
    int end_index = 0;
    for (T i = begin; i < end; i = static_cast<T>(i + step))
      end_index++;
    return end_index;
  }

  // No implementation - assignment is unsupported.
  void operator=(const RangeGenerator& other);

  const T begin_;
  const T end_;
  const IncrementT step_;
  // The index for the end() iterator. All the elements in the generated
  // sequence are indexed (0-based) to aid iterator comparison.
  const int end_index_;
};  // class RangeGenerator


// Generates values from a pair of STL-style iterators. Used in the
// ValuesIn() function. The elements are copied from the source range
// since the source can be located on the stack, and the generator
// is likely to persist beyond that stack frame.
template <typename T>
class ValuesInIteratorRangeGenerator : public ParamGeneratorInterface<T> {
 public:
  template <typename ForwardIterator>
  ValuesInIteratorRangeGenerator(ForwardIterator begin, ForwardIterator end)
      : container_(begin, end) {}
  ~ValuesInIteratorRangeGenerator() override {}

  ParamIteratorInterface<T>* Begin() const override {
    return new Iterator(this, container_.begin());
  }
  ParamIteratorInterface<T>* End() const override {
    return new Iterator(this, container_.end());
  }

 private:
  typedef typename ::std::vector<T> ContainerType;

  class Iterator : public ParamIteratorInterface<T> {
   public:
    Iterator(const ParamGeneratorInterface<T>* base,
             typename ContainerType::const_iterator iterator)
        : base_(base), iterator_(iterator) {}
    ~Iterator() override {}

    const ParamGeneratorInterface<T>* BaseGenerator() const override {
      return base_;
    }
    void Advance() override {
      ++iterator_;
      value_.reset();
    }
    ParamIteratorInterface<T>* Clone() const override {
      return new Iterator(*this);
    }
    // We need to use cached value referenced by iterator_ because *iterator_
    // can return a temporary object (and of type other then T), so just
    // having "return &*iterator_;" doesn't work.
    // value_ is updated here and not in Advance() because Advance()
    // can advance iterator_ beyond the end of the range, and we cannot
    // detect that fact. The client code, on the other hand, is
    // responsible for not calling Current() on an out-of-range iterator.
    const T* Current() const override {
      if (value_.get() == nullptr) value_.reset(new T(*iterator_));
      return value_.get();
    }
    bool Equals(const ParamIteratorInterface<T>& other) const override {
      // Having the same base generator guarantees that the other
      // iterator is of the same type and we can downcast.
      GTEST_CHECK_(BaseGenerator() == other.BaseGenerator())
          << "The program attempted to compare iterators "
          << "from different generators." << std::endl;
      return iterator_ ==
          CheckedDowncastToActualType<const Iterator>(&other)->iterator_;
    }

   private:
    Iterator(const Iterator& other)
          // The explicit constructor call suppresses a false warning
          // emitted by gcc when supplied with the -Wextra option.
        : ParamIteratorInterface<T>(),
          base_(other.base_),
          iterator_(other.iterator_) {}

    const ParamGeneratorInterface<T>* const base_;
    typename ContainerType::const_iterator iterator_;
    // A cached value of *iterator_. We keep it here to allow access by
    // pointer in the wrapping iterator's operator->().
    // value_ needs to be mutable to be accessed in Current().
    // Use of std::unique_ptr helps manage cached value's lifetime,
    // which is bound by the lifespan of the iterator itself.
    mutable std::unique_ptr<const T> value_;
  };  // class ValuesInIteratorRangeGenerator::Iterator

  // No implementation - assignment is unsupported.
  void operator=(const ValuesInIteratorRangeGenerator& other);

  const ContainerType container_;
};  // class ValuesInIteratorRangeGenerator

// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
//
// Default parameterized test name generator, returns a string containing the
// integer test parameter index.
template <class ParamType>
std::string DefaultParamName(const TestParamInfo<ParamType>& info) {
  Message name_stream;
  name_stream << info.index;
  return name_stream.GetString();
}

template <typename T = int>
void TestNotEmpty() {
  static_assert(sizeof(T) == 0, "Empty arguments are not allowed.");
}
template <typename T = int>
void TestNotEmpty(const T&) {}

// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
//
// Stores a parameter value and later creates tests parameterized with that
// value.
template <class TestClass>
class ParameterizedTestFactory : public TestFactoryBase {
 public:
  typedef typename TestClass::ParamType ParamType;
  explicit ParameterizedTestFactory(ParamType parameter) :
      parameter_(parameter) {}
  Test* CreateTest() override {
    TestClass::SetParam(&parameter_);
    return new TestClass();
  }

 private:
  const ParamType parameter_;

  GTEST_DISALLOW_COPY_AND_ASSIGN_(ParameterizedTestFactory);
};

// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
//
// TestMetaFactoryBase is a base class for meta-factories that create
// test factories for passing into MakeAndRegisterTestInfo function.
template <class ParamType>
class TestMetaFactoryBase {
 public:
  virtual ~TestMetaFactoryBase() {}

  virtual TestFactoryBase* CreateTestFactory(ParamType parameter) = 0;
};

// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
//
// TestMetaFactory creates test factories for passing into
// MakeAndRegisterTestInfo function. Since MakeAndRegisterTestInfo receives
// ownership of test factory pointer, same factory object cannot be passed
// into that method twice. But ParameterizedTestSuiteInfo is going to call
// it for each Test/Parameter value combination. Thus it needs meta factory
// creator class.
template <class TestSuite>
class TestMetaFactory
    : public TestMetaFactoryBase<typename TestSuite::ParamType> {
 public:
  using ParamType = typename TestSuite::ParamType;

  TestMetaFactory() {}

  TestFactoryBase* CreateTestFactory(ParamType parameter) override {
    return new ParameterizedTestFactory<TestSuite>(parameter);
  }

 private:
  GTEST_DISALLOW_COPY_AND_ASSIGN_(TestMetaFactory);
};

// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
//
// ParameterizedTestSuiteInfoBase is a generic interface
// to ParameterizedTestSuiteInfo classes. ParameterizedTestSuiteInfoBase
// accumulates test information provided by TEST_P macro invocations
// and generators provided by INSTANTIATE_TEST_SUITE_P macro invocations
// and uses that information to register all resulting test instances
// in RegisterTests method. The ParameterizeTestSuiteRegistry class holds
// a collection of pointers to the ParameterizedTestSuiteInfo objects
// and calls RegisterTests() on each of them when asked.
class ParameterizedTestSuiteInfoBase {
 public:
  virtual ~ParameterizedTestSuiteInfoBase() {}

  // Base part of test suite name for display purposes.
  virtual const std::string& GetTestSuiteName() const = 0;
  // Test suite id to verify identity.
  virtual TypeId GetTestSuiteTypeId() const = 0;
  // UnitTest class invokes this method to register tests in this
  // test suite right before running them in RUN_ALL_TESTS macro.
  // This method should not be called more than once on any single
  // instance of a ParameterizedTestSuiteInfoBase derived class.
  virtual void RegisterTests() = 0;

 protected:
  ParameterizedTestSuiteInfoBase() {}

 private:
  GTEST_DISALLOW_COPY_AND_ASSIGN_(ParameterizedTestSuiteInfoBase);
};

// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
//
// Report a the name of a test_suit as safe to ignore
// as the side effect of construction of this type.
struct GTEST_API_ MarkAsIgnored {
  explicit MarkAsIgnored(const char* test_suite);
};

GTEST_API_ void InsertSyntheticTestCase(const std::string& name,
                                        CodeLocation location, bool has_test_p);

// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
//
// ParameterizedTestSuiteInfo accumulates tests obtained from TEST_P
// macro invocations for a particular test suite and generators
// obtained from INSTANTIATE_TEST_SUITE_P macro invocations for that
// test suite. It registers tests with all values generated by all
// generators when asked.
template <class TestSuite>
class ParameterizedTestSuiteInfo : public ParameterizedTestSuiteInfoBase {
 public:
  // ParamType and GeneratorCreationFunc are private types but are required
  // for declarations of public methods AddTestPattern() and
  // AddTestSuiteInstantiation().
  using ParamType = typename TestSuite::ParamType;
  // A function that returns an instance of appropriate generator type.
  typedef ParamGenerator<ParamType>(GeneratorCreationFunc)();
  using ParamNameGeneratorFunc = std::string(const TestParamInfo<ParamType>&);

  explicit ParameterizedTestSuiteInfo(const char* name,
                                      CodeLocation code_location)
      : test_suite_name_(name), code_location_(code_location) {}

  // Test suite base name for display purposes.
  const std::string& GetTestSuiteName() const override {
    return test_suite_name_;
  }
  // Test suite id to verify identity.
  TypeId GetTestSuiteTypeId() const override { return GetTypeId<TestSuite>(); }
  // TEST_P macro uses AddTestPattern() to record information
  // about a single test in a LocalTestInfo structure.
  // test_suite_name is the base name of the test suite (without invocation
  // prefix). test_base_name is the name of an individual test without
  // parameter index. For the test SequenceA/FooTest.DoBar/1 FooTest is
  // test suite base name and DoBar is test base name.
  void AddTestPattern(const char* test_suite_name, const char* test_base_name,
                      TestMetaFactoryBase<ParamType>* meta_factory,
                      CodeLocation code_location) {
    tests_.push_back(std::shared_ptr<TestInfo>(new TestInfo(
        test_suite_name, test_base_name, meta_factory, code_location)));
  }
  // INSTANTIATE_TEST_SUITE_P macro uses AddGenerator() to record information
  // about a generator.
  int AddTestSuiteInstantiation(const std::string& instantiation_name,
                                GeneratorCreationFunc* func,
                                ParamNameGeneratorFunc* name_func,
                                const char* file, int line) {
    instantiations_.push_back(
        InstantiationInfo(instantiation_name, func, name_func, file, line));
    return 0;  // Return value used only to run this method in namespace scope.
  }
  // UnitTest class invokes this method to register tests in this test suite
  // right before running tests in RUN_ALL_TESTS macro.
  // This method should not be called more than once on any single
  // instance of a ParameterizedTestSuiteInfoBase derived class.
  // UnitTest has a guard to prevent from calling this method more than once.
  void RegisterTests() override {
    bool generated_instantiations = false;

    for (typename TestInfoContainer::iterator test_it = tests_.begin();
         test_it != tests_.end(); ++test_it) {
      std::shared_ptr<TestInfo> test_info = *test_it;
      for (typename InstantiationContainer::iterator gen_it =
               instantiations_.begin(); gen_it != instantiations_.end();
               ++gen_it) {
        const std::string& instantiation_name = gen_it->name;
        ParamGenerator<ParamType> generator((*gen_it->generator)());
        ParamNameGeneratorFunc* name_func = gen_it->name_func;
        const char* file = gen_it->file;
        int line = gen_it->line;

        std::string test_suite_name;
        if ( !instantiation_name.empty() )
          test_suite_name = instantiation_name + "/";
        test_suite_name += test_info->test_suite_base_name;

        size_t i = 0;
        std::set<std::string> test_param_names;
        for (typename ParamGenerator<ParamType>::iterator param_it =
                 generator.begin();
             param_it != generator.end(); ++param_it, ++i) {
          generated_instantiations = true;

          Message test_name_stream;

          std::string param_name = name_func(
              TestParamInfo<ParamType>(*param_it, i));

          GTEST_CHECK_(IsValidParamName(param_name))
              << "Parameterized test name '" << param_name
              << "' is invalid, in " << file
              << " line " << line << std::endl;

          GTEST_CHECK_(test_param_names.count(param_name) == 0)
              << "Duplicate parameterized test name '" << param_name
              << "', in " << file << " line " << line << std::endl;

          test_param_names.insert(param_name);

          if (!test_info->test_base_name.empty()) {
            test_name_stream << test_info->test_base_name << "/";
          }
          test_name_stream << param_name;
          MakeAndRegisterTestInfo(
              test_suite_name.c_str(), test_name_stream.GetString().c_str(),
              nullptr,  // No type parameter.
              PrintToString(*param_it).c_str(), test_info->code_location,
              GetTestSuiteTypeId(),
              SuiteApiResolver<TestSuite>::GetSetUpCaseOrSuite(file, line),
              SuiteApiResolver<TestSuite>::GetTearDownCaseOrSuite(file, line),
              test_info->test_meta_factory->CreateTestFactory(*param_it));
        }  // for param_it
      }  // for gen_it
    }  // for test_it

    if (!generated_instantiations) {
      // There are no generaotrs, or they all generate nothing ...
      InsertSyntheticTestCase(GetTestSuiteName(), code_location_,
                              !tests_.empty());
    }
  }    // RegisterTests

 private:
  // LocalTestInfo structure keeps information about a single test registered
  // with TEST_P macro.
  struct TestInfo {
    TestInfo(const char* a_test_suite_base_name, const char* a_test_base_name,
             TestMetaFactoryBase<ParamType>* a_test_meta_factory,
             CodeLocation a_code_location)
        : test_suite_base_name(a_test_suite_base_name),
          test_base_name(a_test_base_name),
          test_meta_factory(a_test_meta_factory),
          code_location(a_code_location) {}

    const std::string test_suite_base_name;
    const std::string test_base_name;
    const std::unique_ptr<TestMetaFactoryBase<ParamType> > test_meta_factory;
    const CodeLocation code_location;
  };
  using TestInfoContainer = ::std::vector<std::shared_ptr<TestInfo> >;
  // Records data received from INSTANTIATE_TEST_SUITE_P macros:
  //  <Instantiation name, Sequence generator creation function,
  //     Name generator function, Source file, Source line>
  struct InstantiationInfo {
      InstantiationInfo(const std::string &name_in,
                        GeneratorCreationFunc* generator_in,
                        ParamNameGeneratorFunc* name_func_in,
                        const char* file_in,
                        int line_in)
          : name(name_in),
            generator(generator_in),
            name_func(name_func_in),
            file(file_in),
            line(line_in) {}

      std::string name;
      GeneratorCreationFunc* generator;
      ParamNameGeneratorFunc* name_func;
      const char* file;
      int line;
  };
  typedef ::std::vector<InstantiationInfo> InstantiationContainer;

  static bool IsValidParamName(const std::string& name) {
    // Check for empty string
    if (name.empty())
      return false;

    // Check for invalid characters
    for (std::string::size_type index = 0; index < name.size(); ++index) {
      if (!IsAlNum(name[index]) && name[index] != '_')
        return false;
    }

    return true;
  }

  const std::string test_suite_name_;
  CodeLocation code_location_;
  TestInfoContainer tests_;
  InstantiationContainer instantiations_;

  GTEST_DISALLOW_COPY_AND_ASSIGN_(ParameterizedTestSuiteInfo);
};  // class ParameterizedTestSuiteInfo

//  Legacy API is deprecated but still available
#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
template <class TestCase>
using ParameterizedTestCaseInfo = ParameterizedTestSuiteInfo<TestCase>;
#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_

// INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
//
// ParameterizedTestSuiteRegistry contains a map of
// ParameterizedTestSuiteInfoBase classes accessed by test suite names. TEST_P
// and INSTANTIATE_TEST_SUITE_P macros use it to locate their corresponding
// ParameterizedTestSuiteInfo descriptors.
class ParameterizedTestSuiteRegistry {
 public:
  ParameterizedTestSuiteRegistry() {}
  ~ParameterizedTestSuiteRegistry() {
    for (auto& test_suite_info : test_suite_infos_) {
      delete test_suite_info;
    }
  }

  // Looks up or creates and returns a structure containing information about
  // tests and instantiations of a particular test suite.
  template <class TestSuite>
  ParameterizedTestSuiteInfo<TestSuite>* GetTestSuitePatternHolder(
      const char* test_suite_name, CodeLocation code_location) {
    ParameterizedTestSuiteInfo<TestSuite>* typed_test_info = nullptr;
    for (auto& test_suite_info : test_suite_infos_) {
      if (test_suite_info->GetTestSuiteName() == test_suite_name) {
        if (test_suite_info->GetTestSuiteTypeId() != GetTypeId<TestSuite>()) {
          // Complain about incorrect usage of Google Test facilities
          // and terminate the program since we cannot guaranty correct
          // test suite setup and tear-down in this case.
          ReportInvalidTestSuiteType(test_suite_name, code_location);
          posix::Abort();
        } else {
          // At this point we are sure that the object we found is of the same
          // type we are looking for, so we downcast it to that type
          // without further checks.
          typed_test_info = CheckedDowncastToActualType<
              ParameterizedTestSuiteInfo<TestSuite> >(test_suite_info);
        }
        break;
      }
    }
    if (typed_test_info == nullptr) {
      typed_test_info = new ParameterizedTestSuiteInfo<TestSuite>(
          test_suite_name, code_location);
      test_suite_infos_.push_back(typed_test_info);
    }
    return typed_test_info;
  }
  void RegisterTests() {
    for (auto& test_suite_info : test_suite_infos_) {
      test_suite_info->RegisterTests();
    }
  }
//  Legacy API is deprecated but still available
#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI_
  template <class TestCase>
  ParameterizedTestCaseInfo<TestCase>* GetTestCasePatternHolder(
      const char* test_case_name, CodeLocation code_location) {
    return GetTestSuitePatternHolder<TestCase>(test_case_name, code_location);
  }

#endif  //  GTEST_REMOVE_LEGACY_TEST_CASEAPI_

 private:
  using TestSuiteInfoContainer = ::std::vector<ParameterizedTestSuiteInfoBase*>;

  TestSuiteInfoContainer test_suite_infos_;

  GTEST_DISALLOW_COPY_AND_ASSIGN_(ParameterizedTestSuiteRegistry);
};

// Keep track of what type-parameterized test suite are defined and
// where as well as which are intatiated. This allows susequently
// identifying suits that are defined but never used.
class TypeParameterizedTestSuiteRegistry {
 public:
  // Add a suite definition
  void RegisterTestSuite(const char* test_suite_name,
                         CodeLocation code_location);

  // Add an instantiation of a suit.
  void RegisterInstantiation(const char* test_suite_name);

  // For each suit repored as defined but not reported as instantiation,
  // emit a test that reports that fact (configurably, as an error).
  void CheckForInstantiations();

 private:
  struct TypeParameterizedTestSuiteInfo {
    explicit TypeParameterizedTestSuiteInfo(CodeLocation c)
        : code_location(c), instantiated(false) {}

    CodeLocation code_location;
    bool instantiated;
  };

  std::map<std::string, TypeParameterizedTestSuiteInfo> suites_;
};

}  // namespace internal

// Forward declarations of ValuesIn(), which is implemented in
// include/gtest/gtest-param-test.h.
template <class Container>
internal::ParamGenerator<typename Container::value_type> ValuesIn(
    const Container& container);

namespace internal {
// Used in the Values() function to provide polymorphic capabilities.

#ifdef _MSC_VER
#pragma warning(push)
#pragma warning(disable : 4100)
#endif

template <typename... Ts>
class ValueArray {
 public:
  explicit ValueArray(Ts... v) : v_(FlatTupleConstructTag{}, std::move(v)...) {}

  template <typename T>
  operator ParamGenerator<T>() const {  // NOLINT
    return ValuesIn(MakeVector<T>(MakeIndexSequence<sizeof...(Ts)>()));
  }

 private:
  template <typename T, size_t... I>
  std::vector<T> MakeVector(IndexSequence<I...>) const {
    return std::vector<T>{static_cast<T>(v_.template Get<I>())...};
  }

  FlatTuple<Ts...> v_;
};

#ifdef _MSC_VER
#pragma warning(pop)
#endif

template <typename... T>
class CartesianProductGenerator
    : public ParamGeneratorInterface<::std::tuple<T...>> {
 public:
  typedef ::std::tuple<T...> ParamType;

  CartesianProductGenerator(const std::tuple<ParamGenerator<T>...>& g)
      : generators_(g) {}
  ~CartesianProductGenerator() override {}

  ParamIteratorInterface<ParamType>* Begin() const override {
    return new Iterator(this, generators_, false);
  }
  ParamIteratorInterface<ParamType>* End() const override {
    return new Iterator(this, generators_, true);
  }

 private:
  template <class I>
  class IteratorImpl;
  template <size_t... I>
  class IteratorImpl<IndexSequence<I...>>
      : public ParamIteratorInterface<ParamType> {
   public:
    IteratorImpl(const ParamGeneratorInterface<ParamType>* base,
             const std::tuple<ParamGenerator<T>...>& generators, bool is_end)
        : base_(base),
          begin_(std::get<I>(generators).begin()...),
          end_(std::get<I>(generators).end()...),
          current_(is_end ? end_ : begin_) {
      ComputeCurrentValue();
    }
    ~IteratorImpl() override {}

    const ParamGeneratorInterface<ParamType>* BaseGenerator() const override {
      return base_;
    }
    // Advance should not be called on beyond-of-range iterators
    // so no component iterators must be beyond end of range, either.
    void Advance() override {
      assert(!AtEnd());
      // Advance the last iterator.
      ++std::get<sizeof...(T) - 1>(current_);
      // if that reaches end, propagate that up.
      AdvanceIfEnd<sizeof...(T) - 1>();
      ComputeCurrentValue();
    }
    ParamIteratorInterface<ParamType>* Clone() const override {
      return new IteratorImpl(*this);
    }

    const ParamType* Current() const override { return current_value_.get(); }

    bool Equals(const ParamIteratorInterface<ParamType>& other) const override {
      // Having the same base generator guarantees that the other
      // iterator is of the same type and we can downcast.
      GTEST_CHECK_(BaseGenerator() == other.BaseGenerator())
          << "The program attempted to compare iterators "
          << "from different generators." << std::endl;
      const IteratorImpl* typed_other =
          CheckedDowncastToActualType<const IteratorImpl>(&other);

      // We must report iterators equal if they both point beyond their
      // respective ranges. That can happen in a variety of fashions,
      // so we have to consult AtEnd().
      if (AtEnd() && typed_other->AtEnd()) return true;

      bool same = true;
      bool dummy[] = {
          (same = same && std::get<I>(current_) ==
                              std::get<I>(typed_other->current_))...};
      (void)dummy;
      return same;
    }

   private:
    template <size_t ThisI>
    void AdvanceIfEnd() {
      if (std::get<ThisI>(current_) != std::get<ThisI>(end_)) return;

      bool last = ThisI == 0;
      if (last) {
        // We are done. Nothing else to propagate.
        return;
      }

      constexpr size_t NextI = ThisI - (ThisI != 0);
      std::get<ThisI>(current_) = std::get<ThisI>(begin_);
      ++std::get<NextI>(current_);
      AdvanceIfEnd<NextI>();
    }

    void ComputeCurrentValue() {
      if (!AtEnd())
        current_value_ = std::make_shared<ParamType>(*std::get<I>(current_)...);
    }
    bool AtEnd() const {
      bool at_end = false;
      bool dummy[] = {
          (at_end = at_end || std::get<I>(current_) == std::get<I>(end_))...};
      (void)dummy;
      return at_end;
    }

    const ParamGeneratorInterface<ParamType>* const base_;
    std::tuple<typename ParamGenerator<T>::iterator...> begin_;
    std::tuple<typename ParamGenerator<T>::iterator...> end_;
    std::tuple<typename ParamGenerator<T>::iterator...> current_;
    std::shared_ptr<ParamType> current_value_;
  };

  using Iterator = IteratorImpl<typename MakeIndexSequence<sizeof...(T)>::type>;

  std::tuple<ParamGenerator<T>...> generators_;
};

template <class... Gen>
class CartesianProductHolder {
 public:
  CartesianProductHolder(const Gen&... g) : generators_(g...) {}
  template <typename... T>
  operator ParamGenerator<::std::tuple<T...>>() const {
    return ParamGenerator<::std::tuple<T...>>(
        new CartesianProductGenerator<T...>(generators_));
  }

 private:
  std::tuple<Gen...> generators_;
};

}  // namespace internal
}  // namespace testing

#endif  // GOOGLETEST_INCLUDE_GTEST_INTERNAL_GTEST_PARAM_UTIL_H_