duckstation

gtest-port.h (80761B)

---

 // Copyright 2005, 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.
 //
 // Low-level types and utilities for porting Google Test to various
 // platforms.  All macros ending with _ and symbols defined in an
 // internal namespace are subject to change without notice.  Code
 // outside Google Test MUST NOT USE THEM DIRECTLY.  Macros that don't
 // end with _ are part of Google Test's public API and can be used by
 // code outside Google Test.
 //
 // This file is fundamental to Google Test.  All other Google Test source
 // files are expected to #include this.  Therefore, it cannot #include
 // any other Google Test header.
 
 // GOOGLETEST_CM0001 DO NOT DELETE
 
 #ifndef GTEST_INCLUDE_GTEST_INTERNAL_GTEST_PORT_H_
 #define GTEST_INCLUDE_GTEST_INTERNAL_GTEST_PORT_H_
 
 // Environment-describing macros
 // -----------------------------
 //
 // Google Test can be used in many different environments.  Macros in
 // this section tell Google Test what kind of environment it is being
 // used in, such that Google Test can provide environment-specific
 // features and implementations.
 //
 // Google Test tries to automatically detect the properties of its
 // environment, so users usually don't need to worry about these
 // macros.  However, the automatic detection is not perfect.
 // Sometimes it's necessary for a user to define some of the following
 // macros in the build script to override Google Test's decisions.
 //
 // If the user doesn't define a macro in the list, Google Test will
 // provide a default definition.  After this header is #included, all
 // macros in this list will be defined to either 1 or 0.
 //
 // Notes to maintainers:
 //   - Each macro here is a user-tweakable knob; do not grow the list
 //     lightly.
 //   - Use #if to key off these macros.  Don't use #ifdef or "#if
 //     defined(...)", which will not work as these macros are ALWAYS
 //     defined.
 //
 //   GTEST_HAS_CLONE          - Define it to 1/0 to indicate that clone(2)
 //                              is/isn't available.
 //   GTEST_HAS_EXCEPTIONS     - Define it to 1/0 to indicate that exceptions
 //                              are enabled.
 //   GTEST_HAS_POSIX_RE       - Define it to 1/0 to indicate that POSIX regular
 //                              expressions are/aren't available.
 //   GTEST_HAS_PTHREAD        - Define it to 1/0 to indicate that <pthread.h>
 //                              is/isn't available.
 //   GTEST_HAS_RTTI           - Define it to 1/0 to indicate that RTTI is/isn't
 //                              enabled.
 //   GTEST_HAS_STD_WSTRING    - Define it to 1/0 to indicate that
 //                              std::wstring does/doesn't work (Google Test can
 //                              be used where std::wstring is unavailable).
 //   GTEST_HAS_SEH            - Define it to 1/0 to indicate whether the
 //                              compiler supports Microsoft's "Structured
 //                              Exception Handling".
 //   GTEST_HAS_STREAM_REDIRECTION
 //                            - Define it to 1/0 to indicate whether the
 //                              platform supports I/O stream redirection using
 //                              dup() and dup2().
 //   GTEST_LINKED_AS_SHARED_LIBRARY
 //                            - Define to 1 when compiling tests that use
 //                              Google Test as a shared library (known as
 //                              DLL on Windows).
 //   GTEST_CREATE_SHARED_LIBRARY
 //                            - Define to 1 when compiling Google Test itself
 //                              as a shared library.
 //   GTEST_DEFAULT_DEATH_TEST_STYLE
 //                            - The default value of --gtest_death_test_style.
 //                              The legacy default has been "fast" in the open
 //                              source version since 2008. The recommended value
 //                              is "threadsafe", and can be set in
 //                              custom/gtest-port.h.
 
 // Platform-indicating macros
 // --------------------------
 //
 // Macros indicating the platform on which Google Test is being used
 // (a macro is defined to 1 if compiled on the given platform;
 // otherwise UNDEFINED -- it's never defined to 0.).  Google Test
 // defines these macros automatically.  Code outside Google Test MUST
 // NOT define them.
 //
 //   GTEST_OS_AIX      - IBM AIX
 //   GTEST_OS_CYGWIN   - Cygwin
 //   GTEST_OS_DRAGONFLY - DragonFlyBSD
 //   GTEST_OS_FREEBSD  - FreeBSD
 //   GTEST_OS_FUCHSIA  - Fuchsia
 //   GTEST_OS_GNU_KFREEBSD - GNU/kFreeBSD
 //   GTEST_OS_HAIKU    - Haiku
 //   GTEST_OS_HPUX     - HP-UX
 //   GTEST_OS_LINUX    - Linux
 //     GTEST_OS_LINUX_ANDROID - Google Android
 //   GTEST_OS_MAC      - Mac OS X
 //     GTEST_OS_IOS    - iOS
 //   GTEST_OS_NACL     - Google Native Client (NaCl)
 //   GTEST_OS_NETBSD   - NetBSD
 //   GTEST_OS_OPENBSD  - OpenBSD
 //   GTEST_OS_OS2      - OS/2
 //   GTEST_OS_QNX      - QNX
 //   GTEST_OS_SOLARIS  - Sun Solaris
 //   GTEST_OS_WINDOWS  - Windows (Desktop, MinGW, or Mobile)
 //     GTEST_OS_WINDOWS_DESKTOP  - Windows Desktop
 //     GTEST_OS_WINDOWS_MINGW    - MinGW
 //     GTEST_OS_WINDOWS_MOBILE   - Windows Mobile
 //     GTEST_OS_WINDOWS_PHONE    - Windows Phone
 //     GTEST_OS_WINDOWS_RT       - Windows Store App/WinRT
 //   GTEST_OS_ZOS      - z/OS
 //
 // Among the platforms, Cygwin, Linux, Mac OS X, and Windows have the
 // most stable support.  Since core members of the Google Test project
 // don't have access to other platforms, support for them may be less
 // stable.  If you notice any problems on your platform, please notify
 // googletestframework@googlegroups.com (patches for fixing them are
 // even more welcome!).
 //
 // It is possible that none of the GTEST_OS_* macros are defined.
 
 // Feature-indicating macros
 // -------------------------
 //
 // Macros indicating which Google Test features are available (a macro
 // is defined to 1 if the corresponding feature is supported;
 // otherwise UNDEFINED -- it's never defined to 0.).  Google Test
 // defines these macros automatically.  Code outside Google Test MUST
 // NOT define them.
 //
 // These macros are public so that portable tests can be written.
 // Such tests typically surround code using a feature with an #if
 // which controls that code.  For example:
 //
 // #if GTEST_HAS_DEATH_TEST
 //   EXPECT_DEATH(DoSomethingDeadly());
 // #endif
 //
 //   GTEST_HAS_DEATH_TEST   - death tests
 //   GTEST_HAS_TYPED_TEST   - typed tests
 //   GTEST_HAS_TYPED_TEST_P - type-parameterized tests
 //   GTEST_IS_THREADSAFE    - Google Test is thread-safe.
 //   GOOGLETEST_CM0007 DO NOT DELETE
 //   GTEST_USES_POSIX_RE    - enhanced POSIX regex is used. Do not confuse with
 //                            GTEST_HAS_POSIX_RE (see above) which users can
 //                            define themselves.
 //   GTEST_USES_SIMPLE_RE   - our own simple regex is used;
 //                            the above RE\b(s) are mutually exclusive.
 
 // Misc public macros
 // ------------------
 //
 //   GTEST_FLAG(flag_name)  - references the variable corresponding to
 //                            the given Google Test flag.
 
 // Internal utilities
 // ------------------
 //
 // The following macros and utilities are for Google Test's INTERNAL
 // use only.  Code outside Google Test MUST NOT USE THEM DIRECTLY.
 //
 // Macros for basic C++ coding:
 //   GTEST_AMBIGUOUS_ELSE_BLOCKER_ - for disabling a gcc warning.
 //   GTEST_ATTRIBUTE_UNUSED_  - declares that a class' instances or a
 //                              variable don't have to be used.
 //   GTEST_DISALLOW_ASSIGN_   - disables copy operator=.
 //   GTEST_DISALLOW_COPY_AND_ASSIGN_ - disables copy ctor and operator=.
 //   GTEST_DISALLOW_MOVE_ASSIGN_   - disables move operator=.
 //   GTEST_DISALLOW_MOVE_AND_ASSIGN_ - disables move ctor and operator=.
 //   GTEST_MUST_USE_RESULT_   - declares that a function's result must be used.
 //   GTEST_INTENTIONAL_CONST_COND_PUSH_ - start code section where MSVC C4127 is
 //                                        suppressed (constant conditional).
 //   GTEST_INTENTIONAL_CONST_COND_POP_  - finish code section where MSVC C4127
 //                                        is suppressed.
 //   GTEST_INTERNAL_HAS_STRING_VIEW - for enabling Matcher<std::string_view> or
 //                                    Matcher<absl::string_view>
 //                                    specializations.
 //
 // Synchronization:
 //   Mutex, MutexLock, ThreadLocal, GetThreadCount()
 //                            - synchronization primitives.
 //
 // Regular expressions:
 //   RE             - a simple regular expression class using the POSIX
 //                    Extended Regular Expression syntax on UNIX-like platforms
 //                    GOOGLETEST_CM0008 DO NOT DELETE
 //                    or a reduced regular exception syntax on other
 //                    platforms, including Windows.
 // Logging:
 //   GTEST_LOG_()   - logs messages at the specified severity level.
 //   LogToStderr()  - directs all log messages to stderr.
 //   FlushInfoLog() - flushes informational log messages.
 //
 // Stdout and stderr capturing:
 //   CaptureStdout()     - starts capturing stdout.
 //   GetCapturedStdout() - stops capturing stdout and returns the captured
 //                         string.
 //   CaptureStderr()     - starts capturing stderr.
 //   GetCapturedStderr() - stops capturing stderr and returns the captured
 //                         string.
 //
 // Integer types:
 //   TypeWithSize   - maps an integer to a int type.
 //   TimeInMillis   - integers of known sizes.
 //   BiggestInt     - the biggest signed integer type.
 //
 // Command-line utilities:
 //   GTEST_DECLARE_*()  - declares a flag.
 //   GTEST_DEFINE_*()   - defines a flag.
 //   GetInjectableArgvs() - returns the command line as a vector of strings.
 //
 // Environment variable utilities:
 //   GetEnv()             - gets the value of an environment variable.
 //   BoolFromGTestEnv()   - parses a bool environment variable.
 //   Int32FromGTestEnv()  - parses an int32_t environment variable.
 //   StringFromGTestEnv() - parses a string environment variable.
 //
 // Deprecation warnings:
 //   GTEST_INTERNAL_DEPRECATED(message) - attribute marking a function as
 //                                        deprecated; calling a marked function
 //                                        should generate a compiler warning
 
 #include <ctype.h>   // for isspace, etc
 #include <stddef.h>  // for ptrdiff_t
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include <cerrno>
 #include <cstdint>
 #include <limits>
 #include <type_traits>
 
 #ifndef _WIN32_WCE
 # include <sys/types.h>
 # include <sys/stat.h>
 #endif  // !_WIN32_WCE
 
 #if defined __APPLE__
 # include <AvailabilityMacros.h>
 # include <TargetConditionals.h>
 #endif
 
 #include <iostream>  // NOLINT
 #include <memory>
 #include <string>  // NOLINT
 #include <tuple>
 #include <vector>  // NOLINT
 
 #include "gtest/internal/custom/gtest-port.h"
 #include "gtest/internal/gtest-port-arch.h"
 
 #if !defined(GTEST_DEV_EMAIL_)
 # define GTEST_DEV_EMAIL_ "googletestframework@@googlegroups.com"
 # define GTEST_FLAG_PREFIX_ "gtest_"
 # define GTEST_FLAG_PREFIX_DASH_ "gtest-"
 # define GTEST_FLAG_PREFIX_UPPER_ "GTEST_"
 # define GTEST_NAME_ "Google Test"
 # define GTEST_PROJECT_URL_ "https://github.com/google/googletest/"
 #endif  // !defined(GTEST_DEV_EMAIL_)
 
 #if !defined(GTEST_INIT_GOOGLE_TEST_NAME_)
 # define GTEST_INIT_GOOGLE_TEST_NAME_ "testing::InitGoogleTest"
 #endif  // !defined(GTEST_INIT_GOOGLE_TEST_NAME_)
 
 // Determines the version of gcc that is used to compile this.
 #ifdef __GNUC__
 // 40302 means version 4.3.2.
 # define GTEST_GCC_VER_ \
     (__GNUC__*10000 + __GNUC_MINOR__*100 + __GNUC_PATCHLEVEL__)
 #endif  // __GNUC__
 
 // Macros for disabling Microsoft Visual C++ warnings.
 //
 //   GTEST_DISABLE_MSC_WARNINGS_PUSH_(4800 4385)
 //   /* code that triggers warnings C4800 and C4385 */
 //   GTEST_DISABLE_MSC_WARNINGS_POP_()
 #if defined(_MSC_VER)
 # define GTEST_DISABLE_MSC_WARNINGS_PUSH_(warnings) \
     __pragma(warning(push))                        \
     __pragma(warning(disable: warnings))
 # define GTEST_DISABLE_MSC_WARNINGS_POP_()          \
     __pragma(warning(pop))
 #else
 // Not all compilers are MSVC
 # define GTEST_DISABLE_MSC_WARNINGS_PUSH_(warnings)
 # define GTEST_DISABLE_MSC_WARNINGS_POP_()
 #endif
 
 // Clang on Windows does not understand MSVC's pragma warning.
 // We need clang-specific way to disable function deprecation warning.
 #ifdef __clang__
 # define GTEST_DISABLE_MSC_DEPRECATED_PUSH_()                         \
     _Pragma("clang diagnostic push")                                  \
     _Pragma("clang diagnostic ignored \"-Wdeprecated-declarations\"") \
     _Pragma("clang diagnostic ignored \"-Wdeprecated-implementations\"")
 #define GTEST_DISABLE_MSC_DEPRECATED_POP_() \
     _Pragma("clang diagnostic pop")
 #else
 # define GTEST_DISABLE_MSC_DEPRECATED_PUSH_() \
     GTEST_DISABLE_MSC_WARNINGS_PUSH_(4996)
 # define GTEST_DISABLE_MSC_DEPRECATED_POP_() \
     GTEST_DISABLE_MSC_WARNINGS_POP_()
 #endif
 
 // Brings in definitions for functions used in the testing::internal::posix
 // namespace (read, write, close, chdir, isatty, stat). We do not currently
 // use them on Windows Mobile.
 #if GTEST_OS_WINDOWS
 # if !GTEST_OS_WINDOWS_MOBILE
 #  include <direct.h>
 #  include <io.h>
 # endif
 // In order to avoid having to include <windows.h>, use forward declaration
 #if GTEST_OS_WINDOWS_MINGW && !defined(__MINGW64_VERSION_MAJOR)
 // MinGW defined _CRITICAL_SECTION and _RTL_CRITICAL_SECTION as two
 // separate (equivalent) structs, instead of using typedef
 typedef struct _CRITICAL_SECTION GTEST_CRITICAL_SECTION;
 #else
 // Assume CRITICAL_SECTION is a typedef of _RTL_CRITICAL_SECTION.
 // This assumption is verified by
 // WindowsTypesTest.CRITICAL_SECTIONIs_RTL_CRITICAL_SECTION.
 typedef struct _RTL_CRITICAL_SECTION GTEST_CRITICAL_SECTION;
 #endif
 #else
 // This assumes that non-Windows OSes provide unistd.h. For OSes where this
 // is not the case, we need to include headers that provide the functions
 // mentioned above.
 # include <unistd.h>
 # include <strings.h>
 #endif  // GTEST_OS_WINDOWS
 
 #if GTEST_OS_LINUX_ANDROID
 // Used to define __ANDROID_API__ matching the target NDK API level.
 #  include <android/api-level.h>  // NOLINT
 #endif
 
 // Defines this to true if and only if Google Test can use POSIX regular
 // expressions.
 #ifndef GTEST_HAS_POSIX_RE
 # if GTEST_OS_LINUX_ANDROID
 // On Android, <regex.h> is only available starting with Gingerbread.
 #  define GTEST_HAS_POSIX_RE (__ANDROID_API__ >= 9)
 # else
 #  define GTEST_HAS_POSIX_RE (!GTEST_OS_WINDOWS)
 # endif
 #endif
 
 #if GTEST_USES_PCRE
 // The appropriate headers have already been included.
 
 #elif GTEST_HAS_POSIX_RE
 
 // On some platforms, <regex.h> needs someone to define size_t, and
 // won't compile otherwise.  We can #include it here as we already
 // included <stdlib.h>, which is guaranteed to define size_t through
 // <stddef.h>.
 # include <regex.h>  // NOLINT
 
 # define GTEST_USES_POSIX_RE 1
 
 #elif GTEST_OS_WINDOWS
 
 // <regex.h> is not available on Windows.  Use our own simple regex
 // implementation instead.
 # define GTEST_USES_SIMPLE_RE 1
 
 #else
 
 // <regex.h> may not be available on this platform.  Use our own
 // simple regex implementation instead.
 # define GTEST_USES_SIMPLE_RE 1
 
 #endif  // GTEST_USES_PCRE
 
 #ifndef GTEST_HAS_EXCEPTIONS
 // The user didn't tell us whether exceptions are enabled, so we need
 // to figure it out.
 # if defined(_MSC_VER) && defined(_CPPUNWIND)
 // MSVC defines _CPPUNWIND to 1 if and only if exceptions are enabled.
 #  define GTEST_HAS_EXCEPTIONS 1
 # elif defined(__BORLANDC__)
 // C++Builder's implementation of the STL uses the _HAS_EXCEPTIONS
 // macro to enable exceptions, so we'll do the same.
 // Assumes that exceptions are enabled by default.
 #  ifndef _HAS_EXCEPTIONS
 #   define _HAS_EXCEPTIONS 1
 #  endif  // _HAS_EXCEPTIONS
 #  define GTEST_HAS_EXCEPTIONS _HAS_EXCEPTIONS
 # elif defined(__clang__)
 // clang defines __EXCEPTIONS if and only if exceptions are enabled before clang
 // 220714, but if and only if cleanups are enabled after that. In Obj-C++ files,
 // there can be cleanups for ObjC exceptions which also need cleanups, even if
 // C++ exceptions are disabled. clang has __has_feature(cxx_exceptions) which
 // checks for C++ exceptions starting at clang r206352, but which checked for
 // cleanups prior to that. To reliably check for C++ exception availability with
 // clang, check for
 // __EXCEPTIONS && __has_feature(cxx_exceptions).
 #  define GTEST_HAS_EXCEPTIONS (__EXCEPTIONS && __has_feature(cxx_exceptions))
 # elif defined(__GNUC__) && __EXCEPTIONS
 // gcc defines __EXCEPTIONS to 1 if and only if exceptions are enabled.
 #  define GTEST_HAS_EXCEPTIONS 1
 # elif defined(__SUNPRO_CC)
 // Sun Pro CC supports exceptions.  However, there is no compile-time way of
 // detecting whether they are enabled or not.  Therefore, we assume that
 // they are enabled unless the user tells us otherwise.
 #  define GTEST_HAS_EXCEPTIONS 1
 # elif defined(__IBMCPP__) && __EXCEPTIONS
 // xlC defines __EXCEPTIONS to 1 if and only if exceptions are enabled.
 #  define GTEST_HAS_EXCEPTIONS 1
 # elif defined(__HP_aCC)
 // Exception handling is in effect by default in HP aCC compiler. It has to
 // be turned of by +noeh compiler option if desired.
 #  define GTEST_HAS_EXCEPTIONS 1
 # else
 // For other compilers, we assume exceptions are disabled to be
 // conservative.
 #  define GTEST_HAS_EXCEPTIONS 0
 # endif  // defined(_MSC_VER) || defined(__BORLANDC__)
 #endif  // GTEST_HAS_EXCEPTIONS
 
 #ifndef GTEST_HAS_STD_WSTRING
 // The user didn't tell us whether ::std::wstring is available, so we need
 // to figure it out.
 // Cygwin 1.7 and below doesn't support ::std::wstring.
 // Solaris' libc++ doesn't support it either.  Android has
 // no support for it at least as recent as Froyo (2.2).
 #define GTEST_HAS_STD_WSTRING                                         \
   (!(GTEST_OS_LINUX_ANDROID || GTEST_OS_CYGWIN || GTEST_OS_SOLARIS || \
      GTEST_OS_HAIKU || GTEST_OS_ESP32 || GTEST_OS_ESP8266))
 
 #endif  // GTEST_HAS_STD_WSTRING
 
 // Determines whether RTTI is available.
 #ifndef GTEST_HAS_RTTI
 // The user didn't tell us whether RTTI is enabled, so we need to
 // figure it out.
 
 # ifdef _MSC_VER
 
 #ifdef _CPPRTTI  // MSVC defines this macro if and only if RTTI is enabled.
 #   define GTEST_HAS_RTTI 1
 #  else
 #   define GTEST_HAS_RTTI 0
 #  endif
 
 // Starting with version 4.3.2, gcc defines __GXX_RTTI if and only if RTTI is
 // enabled.
 # elif defined(__GNUC__)
 
 #  ifdef __GXX_RTTI
 // When building against STLport with the Android NDK and with
 // -frtti -fno-exceptions, the build fails at link time with undefined
 // references to __cxa_bad_typeid. Note sure if STL or toolchain bug,
 // so disable RTTI when detected.
 #   if GTEST_OS_LINUX_ANDROID && defined(_STLPORT_MAJOR) && \
        !defined(__EXCEPTIONS)
 #    define GTEST_HAS_RTTI 0
 #   else
 #    define GTEST_HAS_RTTI 1
 #   endif  // GTEST_OS_LINUX_ANDROID && __STLPORT_MAJOR && !__EXCEPTIONS
 #  else
 #   define GTEST_HAS_RTTI 0
 #  endif  // __GXX_RTTI
 
 // Clang defines __GXX_RTTI starting with version 3.0, but its manual recommends
 // using has_feature instead. has_feature(cxx_rtti) is supported since 2.7, the
 // first version with C++ support.
 # elif defined(__clang__)
 
 #  define GTEST_HAS_RTTI __has_feature(cxx_rtti)
 
 // Starting with version 9.0 IBM Visual Age defines __RTTI_ALL__ to 1 if
 // both the typeid and dynamic_cast features are present.
 # elif defined(__IBMCPP__) && (__IBMCPP__ >= 900)
 
 #  ifdef __RTTI_ALL__
 #   define GTEST_HAS_RTTI 1
 #  else
 #   define GTEST_HAS_RTTI 0
 #  endif
 
 # else
 
 // For all other compilers, we assume RTTI is enabled.
 #  define GTEST_HAS_RTTI 1
 
 # endif  // _MSC_VER
 
 #endif  // GTEST_HAS_RTTI
 
 // It's this header's responsibility to #include <typeinfo> when RTTI
 // is enabled.
 #if GTEST_HAS_RTTI
 # include <typeinfo>
 #endif
 
 // Determines whether Google Test can use the pthreads library.
 #ifndef GTEST_HAS_PTHREAD
 // The user didn't tell us explicitly, so we make reasonable assumptions about
 // which platforms have pthreads support.
 //
 // To disable threading support in Google Test, add -DGTEST_HAS_PTHREAD=0
 // to your compiler flags.
 #define GTEST_HAS_PTHREAD                                                      \
   (GTEST_OS_LINUX || GTEST_OS_MAC || GTEST_OS_HPUX || GTEST_OS_QNX ||          \
    GTEST_OS_FREEBSD || GTEST_OS_NACL || GTEST_OS_NETBSD || GTEST_OS_FUCHSIA || \
    GTEST_OS_DRAGONFLY || GTEST_OS_GNU_KFREEBSD || GTEST_OS_OPENBSD ||          \
    GTEST_OS_HAIKU)
 #endif  // GTEST_HAS_PTHREAD
 
 #if GTEST_HAS_PTHREAD
 // gtest-port.h guarantees to #include <pthread.h> when GTEST_HAS_PTHREAD is
 // true.
 # include <pthread.h>  // NOLINT
 
 // For timespec and nanosleep, used below.
 # include <time.h>  // NOLINT
 #endif
 
 // Determines whether clone(2) is supported.
 // Usually it will only be available on Linux, excluding
 // Linux on the Itanium architecture.
 // Also see http://linux.die.net/man/2/clone.
 #ifndef GTEST_HAS_CLONE
 // The user didn't tell us, so we need to figure it out.
 
 # if GTEST_OS_LINUX && !defined(__ia64__)
 #  if GTEST_OS_LINUX_ANDROID
 // On Android, clone() became available at different API levels for each 32-bit
 // architecture.
 #    if defined(__LP64__) || \
         (defined(__arm__) && __ANDROID_API__ >= 9) || \
         (defined(__mips__) && __ANDROID_API__ >= 12) || \
         (defined(__i386__) && __ANDROID_API__ >= 17)
 #     define GTEST_HAS_CLONE 1
 #    else
 #     define GTEST_HAS_CLONE 0
 #    endif
 #  else
 #   define GTEST_HAS_CLONE 1
 #  endif
 # else
 #  define GTEST_HAS_CLONE 0
 # endif  // GTEST_OS_LINUX && !defined(__ia64__)
 
 #endif  // GTEST_HAS_CLONE
 
 // Determines whether to support stream redirection. This is used to test
 // output correctness and to implement death tests.
 #ifndef GTEST_HAS_STREAM_REDIRECTION
 // By default, we assume that stream redirection is supported on all
 // platforms except known mobile ones.
 #if GTEST_OS_WINDOWS_MOBILE || GTEST_OS_WINDOWS_PHONE || \
     GTEST_OS_WINDOWS_RT || GTEST_OS_ESP8266
 #  define GTEST_HAS_STREAM_REDIRECTION 0
 # else
 #  define GTEST_HAS_STREAM_REDIRECTION 1
 # endif  // !GTEST_OS_WINDOWS_MOBILE
 #endif  // GTEST_HAS_STREAM_REDIRECTION
 
 // Determines whether to support death tests.
 // pops up a dialog window that cannot be suppressed programmatically.
 #if (GTEST_OS_LINUX || GTEST_OS_CYGWIN || GTEST_OS_SOLARIS ||             \
      (GTEST_OS_MAC && !GTEST_OS_IOS) ||                                   \
      (GTEST_OS_WINDOWS_DESKTOP && _MSC_VER) || GTEST_OS_WINDOWS_MINGW ||  \
      GTEST_OS_AIX || GTEST_OS_HPUX || GTEST_OS_OPENBSD || GTEST_OS_QNX || \
      GTEST_OS_FREEBSD || GTEST_OS_NETBSD || GTEST_OS_FUCHSIA ||           \
      GTEST_OS_DRAGONFLY || GTEST_OS_GNU_KFREEBSD || GTEST_OS_HAIKU)
 # define GTEST_HAS_DEATH_TEST 1
 #endif
 
 // Determines whether to support type-driven tests.
 
 // Typed tests need <typeinfo> and variadic macros, which GCC, VC++ 8.0,
 // Sun Pro CC, IBM Visual Age, and HP aCC support.
 #if defined(__GNUC__) || defined(_MSC_VER) || defined(__SUNPRO_CC) || \
     defined(__IBMCPP__) || defined(__HP_aCC)
 # define GTEST_HAS_TYPED_TEST 1
 # define GTEST_HAS_TYPED_TEST_P 1
 #endif
 
 // Determines whether the system compiler uses UTF-16 for encoding wide strings.
 #define GTEST_WIDE_STRING_USES_UTF16_ \
   (GTEST_OS_WINDOWS || GTEST_OS_CYGWIN || GTEST_OS_AIX || GTEST_OS_OS2)
 
 // Determines whether test results can be streamed to a socket.
 #if GTEST_OS_LINUX || GTEST_OS_GNU_KFREEBSD || GTEST_OS_DRAGONFLY || \
     GTEST_OS_FREEBSD || GTEST_OS_NETBSD || GTEST_OS_OPENBSD
 # define GTEST_CAN_STREAM_RESULTS_ 1
 #endif
 
 // Defines some utility macros.
 
 // The GNU compiler emits a warning if nested "if" statements are followed by
 // an "else" statement and braces are not used to explicitly disambiguate the
 // "else" binding.  This leads to problems with code like:
 //
 //   if (gate)
 //     ASSERT_*(condition) << "Some message";
 //
 // The "switch (0) case 0:" idiom is used to suppress this.
 #ifdef __INTEL_COMPILER
 # define GTEST_AMBIGUOUS_ELSE_BLOCKER_
 #else
 # define GTEST_AMBIGUOUS_ELSE_BLOCKER_ switch (0) case 0: default:  // NOLINT
 #endif
 
 // Use this annotation at the end of a struct/class definition to
 // prevent the compiler from optimizing away instances that are never
 // used.  This is useful when all interesting logic happens inside the
 // c'tor and / or d'tor.  Example:
 //
 //   struct Foo {
 //     Foo() { ... }
 //   } GTEST_ATTRIBUTE_UNUSED_;
 //
 // Also use it after a variable or parameter declaration to tell the
 // compiler the variable/parameter does not have to be used.
 #if defined(__GNUC__) && !defined(COMPILER_ICC)
 # define GTEST_ATTRIBUTE_UNUSED_ __attribute__ ((unused))
 #elif defined(__clang__)
 # if __has_attribute(unused)
 #  define GTEST_ATTRIBUTE_UNUSED_ __attribute__ ((unused))
 # endif
 #endif
 #ifndef GTEST_ATTRIBUTE_UNUSED_
 # define GTEST_ATTRIBUTE_UNUSED_
 #endif
 
 // Use this annotation before a function that takes a printf format string.
 #if (defined(__GNUC__) || defined(__clang__)) && !defined(COMPILER_ICC)
 # if defined(__MINGW_PRINTF_FORMAT)
 // MinGW has two different printf implementations. Ensure the format macro
 // matches the selected implementation. See
 // https://sourceforge.net/p/mingw-w64/wiki2/gnu%20printf/.
 #  define GTEST_ATTRIBUTE_PRINTF_(string_index, first_to_check) \
        __attribute__((__format__(__MINGW_PRINTF_FORMAT, string_index, \
                                  first_to_check)))
 # else
 #  define GTEST_ATTRIBUTE_PRINTF_(string_index, first_to_check) \
        __attribute__((__format__(__printf__, string_index, first_to_check)))
 # endif
 #else
 # define GTEST_ATTRIBUTE_PRINTF_(string_index, first_to_check)
 #endif
 
 
 // A macro to disallow copy operator=
 // This should be used in the private: declarations for a class.
 #define GTEST_DISALLOW_ASSIGN_(type) \
   type& operator=(type const &) = delete
 
 // A macro to disallow copy constructor and operator=
 // This should be used in the private: declarations for a class.
 #define GTEST_DISALLOW_COPY_AND_ASSIGN_(type) \
   type(type const &) = delete; \
   GTEST_DISALLOW_ASSIGN_(type)
 
 // A macro to disallow move operator=
 // This should be used in the private: declarations for a class.
 #define GTEST_DISALLOW_MOVE_ASSIGN_(type) \
   type& operator=(type &&) noexcept = delete
 
 // A macro to disallow move constructor and operator=
 // This should be used in the private: declarations for a class.
 #define GTEST_DISALLOW_MOVE_AND_ASSIGN_(type) \
   type(type &&) noexcept = delete; \
   GTEST_DISALLOW_MOVE_ASSIGN_(type)
 
 // Tell the compiler to warn about unused return values for functions declared
 // with this macro.  The macro should be used on function declarations
 // following the argument list:
 //
 //   Sprocket* AllocateSprocket() GTEST_MUST_USE_RESULT_;
 #if defined(__GNUC__) && !defined(COMPILER_ICC)
 # define GTEST_MUST_USE_RESULT_ __attribute__ ((warn_unused_result))
 #else
 # define GTEST_MUST_USE_RESULT_
 #endif  // __GNUC__ && !COMPILER_ICC
 
 // MS C++ compiler emits warning when a conditional expression is compile time
 // constant. In some contexts this warning is false positive and needs to be
 // suppressed. Use the following two macros in such cases:
 //
 // GTEST_INTENTIONAL_CONST_COND_PUSH_()
 // while (true) {
 // GTEST_INTENTIONAL_CONST_COND_POP_()
 // }
 # define GTEST_INTENTIONAL_CONST_COND_PUSH_() \
     GTEST_DISABLE_MSC_WARNINGS_PUSH_(4127)
 # define GTEST_INTENTIONAL_CONST_COND_POP_() \
     GTEST_DISABLE_MSC_WARNINGS_POP_()
 
 // Determine whether the compiler supports Microsoft's Structured Exception
 // Handling.  This is supported by several Windows compilers but generally
 // does not exist on any other system.
 #ifndef GTEST_HAS_SEH
 // The user didn't tell us, so we need to figure it out.
 
 # if defined(_MSC_VER) || defined(__BORLANDC__)
 // These two compilers are known to support SEH.
 #  define GTEST_HAS_SEH 1
 # else
 // Assume no SEH.
 #  define GTEST_HAS_SEH 0
 # endif
 
 #endif  // GTEST_HAS_SEH
 
 #ifndef GTEST_IS_THREADSAFE
 
 #define GTEST_IS_THREADSAFE                                                 \
   (GTEST_HAS_MUTEX_AND_THREAD_LOCAL_ ||                                     \
    (GTEST_OS_WINDOWS && !GTEST_OS_WINDOWS_PHONE && !GTEST_OS_WINDOWS_RT) || \
    GTEST_HAS_PTHREAD)
 
 #endif  // GTEST_IS_THREADSAFE
 
 // GTEST_API_ qualifies all symbols that must be exported. The definitions below
 // are guarded by #ifndef to give embedders a chance to define GTEST_API_ in
 // gtest/internal/custom/gtest-port.h
 #ifndef GTEST_API_
 
 #ifdef _MSC_VER
 # if GTEST_LINKED_AS_SHARED_LIBRARY
 #  define GTEST_API_ __declspec(dllimport)
 # elif GTEST_CREATE_SHARED_LIBRARY
 #  define GTEST_API_ __declspec(dllexport)
 # endif
 #elif __GNUC__ >= 4 || defined(__clang__)
 # define GTEST_API_ __attribute__((visibility ("default")))
 #endif  // _MSC_VER
 
 #endif  // GTEST_API_
 
 #ifndef GTEST_API_
 # define GTEST_API_
 #endif  // GTEST_API_
 
 #ifndef GTEST_DEFAULT_DEATH_TEST_STYLE
 # define GTEST_DEFAULT_DEATH_TEST_STYLE  "fast"
 #endif  // GTEST_DEFAULT_DEATH_TEST_STYLE
 
 #ifdef __GNUC__
 // Ask the compiler to never inline a given function.
 # define GTEST_NO_INLINE_ __attribute__((noinline))
 #else
 # define GTEST_NO_INLINE_
 #endif
 
 // _LIBCPP_VERSION is defined by the libc++ library from the LLVM project.
 #if !defined(GTEST_HAS_CXXABI_H_)
 # if defined(__GLIBCXX__) || (defined(_LIBCPP_VERSION) && !defined(_MSC_VER))
 #  define GTEST_HAS_CXXABI_H_ 1
 # else
 #  define GTEST_HAS_CXXABI_H_ 0
 # endif
 #endif
 
 // A function level attribute to disable checking for use of uninitialized
 // memory when built with MemorySanitizer.
 #if defined(__clang__)
 # if __has_feature(memory_sanitizer)
 #  define GTEST_ATTRIBUTE_NO_SANITIZE_MEMORY_ \
        __attribute__((no_sanitize_memory))
 # else
 #  define GTEST_ATTRIBUTE_NO_SANITIZE_MEMORY_
 # endif  // __has_feature(memory_sanitizer)
 #else
 # define GTEST_ATTRIBUTE_NO_SANITIZE_MEMORY_
 #endif  // __clang__
 
 // A function level attribute to disable AddressSanitizer instrumentation.
 #if defined(__clang__)
 # if __has_feature(address_sanitizer)
 #  define GTEST_ATTRIBUTE_NO_SANITIZE_ADDRESS_ \
        __attribute__((no_sanitize_address))
 # else
 #  define GTEST_ATTRIBUTE_NO_SANITIZE_ADDRESS_
 # endif  // __has_feature(address_sanitizer)
 #else
 # define GTEST_ATTRIBUTE_NO_SANITIZE_ADDRESS_
 #endif  // __clang__
 
 // A function level attribute to disable HWAddressSanitizer instrumentation.
 #if defined(__clang__)
 # if __has_feature(hwaddress_sanitizer)
 #  define GTEST_ATTRIBUTE_NO_SANITIZE_HWADDRESS_ \
        __attribute__((no_sanitize("hwaddress")))
 # else
 #  define GTEST_ATTRIBUTE_NO_SANITIZE_HWADDRESS_
 # endif  // __has_feature(hwaddress_sanitizer)
 #else
 # define GTEST_ATTRIBUTE_NO_SANITIZE_HWADDRESS_
 #endif  // __clang__
 
 // A function level attribute to disable ThreadSanitizer instrumentation.
 #if defined(__clang__)
 # if __has_feature(thread_sanitizer)
 #  define GTEST_ATTRIBUTE_NO_SANITIZE_THREAD_ \
        __attribute__((no_sanitize_thread))
 # else
 #  define GTEST_ATTRIBUTE_NO_SANITIZE_THREAD_
 # endif  // __has_feature(thread_sanitizer)
 #else
 # define GTEST_ATTRIBUTE_NO_SANITIZE_THREAD_
 #endif  // __clang__
 
 namespace testing {
 
 class Message;
 
 // Legacy imports for backwards compatibility.
 // New code should use std:: names directly.
 using std::get;
 using std::make_tuple;
 using std::tuple;
 using std::tuple_element;
 using std::tuple_size;
 
 namespace internal {
 
 // A secret type that Google Test users don't know about.  It has no
 // definition on purpose.  Therefore it's impossible to create a
 // Secret object, which is what we want.
 class Secret;
 
 // The GTEST_COMPILE_ASSERT_ is a legacy macro used to verify that a compile
 // time expression is true (in new code, use static_assert instead). For
 // example, you could use it to verify the size of a static array:
 //
 //   GTEST_COMPILE_ASSERT_(GTEST_ARRAY_SIZE_(names) == NUM_NAMES,
 //                         names_incorrect_size);
 //
 // The second argument to the macro must be a valid C++ identifier. If the
 // expression is false, compiler will issue an error containing this identifier.
 #define GTEST_COMPILE_ASSERT_(expr, msg) static_assert(expr, #msg)
 
 // A helper for suppressing warnings on constant condition.  It just
 // returns 'condition'.
 GTEST_API_ bool IsTrue(bool condition);
 
 // Defines RE.
 
 #if GTEST_USES_PCRE
 // if used, PCRE is injected by custom/gtest-port.h
 #elif GTEST_USES_POSIX_RE || GTEST_USES_SIMPLE_RE
 
 // A simple C++ wrapper for <regex.h>.  It uses the POSIX Extended
 // Regular Expression syntax.
 class GTEST_API_ RE {
  public:
   // A copy constructor is required by the Standard to initialize object
   // references from r-values.
   RE(const RE& other) { Init(other.pattern()); }
 
   // Constructs an RE from a string.
   RE(const ::std::string& regex) { Init(regex.c_str()); }  // NOLINT
 
   RE(const char* regex) { Init(regex); }  // NOLINT
   ~RE();
 
   // Returns the string representation of the regex.
   const char* pattern() const { return pattern_; }
 
   // FullMatch(str, re) returns true if and only if regular expression re
   // matches the entire str.
   // PartialMatch(str, re) returns true if and only if regular expression re
   // matches a substring of str (including str itself).
   static bool FullMatch(const ::std::string& str, const RE& re) {
     return FullMatch(str.c_str(), re);
   }
   static bool PartialMatch(const ::std::string& str, const RE& re) {
     return PartialMatch(str.c_str(), re);
   }
 
   static bool FullMatch(const char* str, const RE& re);
   static bool PartialMatch(const char* str, const RE& re);
 
  private:
   void Init(const char* regex);
   const char* pattern_;
   bool is_valid_;
 
 # if GTEST_USES_POSIX_RE
 
   regex_t full_regex_;     // For FullMatch().
   regex_t partial_regex_;  // For PartialMatch().
 
 # else  // GTEST_USES_SIMPLE_RE
 
   const char* full_pattern_;  // For FullMatch();
 
 # endif
 
   GTEST_DISALLOW_ASSIGN_(RE);
 };
 
 #endif  // GTEST_USES_PCRE
 
 // Formats a source file path and a line number as they would appear
 // in an error message from the compiler used to compile this code.
 GTEST_API_ ::std::string FormatFileLocation(const char* file, int line);
 
 // Formats a file location for compiler-independent XML output.
 // Although this function is not platform dependent, we put it next to
 // FormatFileLocation in order to contrast the two functions.
 GTEST_API_ ::std::string FormatCompilerIndependentFileLocation(const char* file,
                                                                int line);
 
 // Defines logging utilities:
 //   GTEST_LOG_(severity) - logs messages at the specified severity level. The
 //                          message itself is streamed into the macro.
 //   LogToStderr()  - directs all log messages to stderr.
 //   FlushInfoLog() - flushes informational log messages.
 
 enum GTestLogSeverity {
   GTEST_INFO,
   GTEST_WARNING,
   GTEST_ERROR,
   GTEST_FATAL
 };
 
 // Formats log entry severity, provides a stream object for streaming the
 // log message, and terminates the message with a newline when going out of
 // scope.
 class GTEST_API_ GTestLog {
  public:
   GTestLog(GTestLogSeverity severity, const char* file, int line);
 
   // Flushes the buffers and, if severity is GTEST_FATAL, aborts the program.
   ~GTestLog();
 
   ::std::ostream& GetStream() { return ::std::cerr; }
 
  private:
   const GTestLogSeverity severity_;
 
   GTEST_DISALLOW_COPY_AND_ASSIGN_(GTestLog);
 };
 
 #if !defined(GTEST_LOG_)
 
 # define GTEST_LOG_(severity) \
     ::testing::internal::GTestLog(::testing::internal::GTEST_##severity, \
                                   __FILE__, __LINE__).GetStream()
 
 inline void LogToStderr() {}
 inline void FlushInfoLog() { fflush(nullptr); }
 
 #endif  // !defined(GTEST_LOG_)
 
 #if !defined(GTEST_CHECK_)
 // INTERNAL IMPLEMENTATION - DO NOT USE.
 //
 // GTEST_CHECK_ is an all-mode assert. It aborts the program if the condition
 // is not satisfied.
 //  Synopsys:
 //    GTEST_CHECK_(boolean_condition);
 //     or
 //    GTEST_CHECK_(boolean_condition) << "Additional message";
 //
 //    This checks the condition and if the condition is not satisfied
 //    it prints message about the condition violation, including the
 //    condition itself, plus additional message streamed into it, if any,
 //    and then it aborts the program. It aborts the program irrespective of
 //    whether it is built in the debug mode or not.
 # define GTEST_CHECK_(condition) \
     GTEST_AMBIGUOUS_ELSE_BLOCKER_ \
     if (::testing::internal::IsTrue(condition)) \
       ; \
     else \
       GTEST_LOG_(FATAL) << "Condition " #condition " failed. "
 #endif  // !defined(GTEST_CHECK_)
 
 // An all-mode assert to verify that the given POSIX-style function
 // call returns 0 (indicating success).  Known limitation: this
 // doesn't expand to a balanced 'if' statement, so enclose the macro
 // in {} if you need to use it as the only statement in an 'if'
 // branch.
 #define GTEST_CHECK_POSIX_SUCCESS_(posix_call) \
   if (const int gtest_error = (posix_call)) \
     GTEST_LOG_(FATAL) << #posix_call << "failed with error " \
                       << gtest_error
 
 // Transforms "T" into "const T&" according to standard reference collapsing
 // rules (this is only needed as a backport for C++98 compilers that do not
 // support reference collapsing). Specifically, it transforms:
 //
 //   char         ==> const char&
 //   const char   ==> const char&
 //   char&        ==> char&
 //   const char&  ==> const char&
 //
 // Note that the non-const reference will not have "const" added. This is
 // standard, and necessary so that "T" can always bind to "const T&".
 template <typename T>
 struct ConstRef { typedef const T& type; };
 template <typename T>
 struct ConstRef<T&> { typedef T& type; };
 
 // The argument T must depend on some template parameters.
 #define GTEST_REFERENCE_TO_CONST_(T) \
   typename ::testing::internal::ConstRef<T>::type
 
 // INTERNAL IMPLEMENTATION - DO NOT USE IN USER CODE.
 //
 // Use ImplicitCast_ as a safe version of static_cast for upcasting in
 // the type hierarchy (e.g. casting a Foo* to a SuperclassOfFoo* or a
 // const Foo*).  When you use ImplicitCast_, the compiler checks that
 // the cast is safe.  Such explicit ImplicitCast_s are necessary in
 // surprisingly many situations where C++ demands an exact type match
 // instead of an argument type convertable to a target type.
 //
 // The syntax for using ImplicitCast_ is the same as for static_cast:
 //
 //   ImplicitCast_<ToType>(expr)
 //
 // ImplicitCast_ would have been part of the C++ standard library,
 // but the proposal was submitted too late.  It will probably make
 // its way into the language in the future.
 //
 // This relatively ugly name is intentional. It prevents clashes with
 // similar functions users may have (e.g., implicit_cast). The internal
 // namespace alone is not enough because the function can be found by ADL.
 template<typename To>
 inline To ImplicitCast_(To x) { return x; }
 
 // When you upcast (that is, cast a pointer from type Foo to type
 // SuperclassOfFoo), it's fine to use ImplicitCast_<>, since upcasts
 // always succeed.  When you downcast (that is, cast a pointer from
 // type Foo to type SubclassOfFoo), static_cast<> isn't safe, because
 // how do you know the pointer is really of type SubclassOfFoo?  It
 // could be a bare Foo, or of type DifferentSubclassOfFoo.  Thus,
 // when you downcast, you should use this macro.  In debug mode, we
 // use dynamic_cast<> to double-check the downcast is legal (we die
 // if it's not).  In normal mode, we do the efficient static_cast<>
 // instead.  Thus, it's important to test in debug mode to make sure
 // the cast is legal!
 //    This is the only place in the code we should use dynamic_cast<>.
 // In particular, you SHOULDN'T be using dynamic_cast<> in order to
 // do RTTI (eg code like this:
 //    if (dynamic_cast<Subclass1>(foo)) HandleASubclass1Object(foo);
 //    if (dynamic_cast<Subclass2>(foo)) HandleASubclass2Object(foo);
 // You should design the code some other way not to need this.
 //
 // This relatively ugly name is intentional. It prevents clashes with
 // similar functions users may have (e.g., down_cast). The internal
 // namespace alone is not enough because the function can be found by ADL.
 template<typename To, typename From>  // use like this: DownCast_<T*>(foo);
 inline To DownCast_(From* f) {  // so we only accept pointers
   // Ensures that To is a sub-type of From *.  This test is here only
   // for compile-time type checking, and has no overhead in an
   // optimized build at run-time, as it will be optimized away
   // completely.
   GTEST_INTENTIONAL_CONST_COND_PUSH_()
   if (false) {
   GTEST_INTENTIONAL_CONST_COND_POP_()
   const To to = nullptr;
   ::testing::internal::ImplicitCast_<From*>(to);
   }
 
 #if GTEST_HAS_RTTI
   // RTTI: debug mode only!
   GTEST_CHECK_(f == nullptr || dynamic_cast<To>(f) != nullptr);
 #endif
   return static_cast<To>(f);
 }
 
 // Downcasts the pointer of type Base to Derived.
 // Derived must be a subclass of Base. The parameter MUST
 // point to a class of type Derived, not any subclass of it.
 // When RTTI is available, the function performs a runtime
 // check to enforce this.
 template <class Derived, class Base>
 Derived* CheckedDowncastToActualType(Base* base) {
 #if GTEST_HAS_RTTI
   GTEST_CHECK_(typeid(*base) == typeid(Derived));
 #endif
 
 #if GTEST_HAS_DOWNCAST_
   return ::down_cast<Derived*>(base);
 #elif GTEST_HAS_RTTI
   return dynamic_cast<Derived*>(base);  // NOLINT
 #else
   return static_cast<Derived*>(base);  // Poor man's downcast.
 #endif
 }
 
 #if GTEST_HAS_STREAM_REDIRECTION
 
 // Defines the stderr capturer:
 //   CaptureStdout     - starts capturing stdout.
 //   GetCapturedStdout - stops capturing stdout and returns the captured string.
 //   CaptureStderr     - starts capturing stderr.
 //   GetCapturedStderr - stops capturing stderr and returns the captured string.
 //
 GTEST_API_ void CaptureStdout();
 GTEST_API_ std::string GetCapturedStdout();
 GTEST_API_ void CaptureStderr();
 GTEST_API_ std::string GetCapturedStderr();
 
 #endif  // GTEST_HAS_STREAM_REDIRECTION
 // Returns the size (in bytes) of a file.
 GTEST_API_ size_t GetFileSize(FILE* file);
 
 // Reads the entire content of a file as a string.
 GTEST_API_ std::string ReadEntireFile(FILE* file);
 
 // All command line arguments.
 GTEST_API_ std::vector<std::string> GetArgvs();
 
 #if GTEST_HAS_DEATH_TEST
 
 std::vector<std::string> GetInjectableArgvs();
 // Deprecated: pass the args vector by value instead.
 void SetInjectableArgvs(const std::vector<std::string>* new_argvs);
 void SetInjectableArgvs(const std::vector<std::string>& new_argvs);
 void ClearInjectableArgvs();
 
 #endif  // GTEST_HAS_DEATH_TEST
 
 // Defines synchronization primitives.
 #if GTEST_IS_THREADSAFE
 # if GTEST_HAS_PTHREAD
 // Sleeps for (roughly) n milliseconds.  This function is only for testing
 // Google Test's own constructs.  Don't use it in user tests, either
 // directly or indirectly.
 inline void SleepMilliseconds(int n) {
   const timespec time = {
     0,                  // 0 seconds.
     n * 1000L * 1000L,  // And n ms.
   };
   nanosleep(&time, nullptr);
 }
 # endif  // GTEST_HAS_PTHREAD
 
 # if GTEST_HAS_NOTIFICATION_
 // Notification has already been imported into the namespace.
 // Nothing to do here.
 
 # elif GTEST_HAS_PTHREAD
 // Allows a controller thread to pause execution of newly created
 // threads until notified.  Instances of this class must be created
 // and destroyed in the controller thread.
 //
 // This class is only for testing Google Test's own constructs. Do not
 // use it in user tests, either directly or indirectly.
 class Notification {
  public:
   Notification() : notified_(false) {
     GTEST_CHECK_POSIX_SUCCESS_(pthread_mutex_init(&mutex_, nullptr));
   }
   ~Notification() {
     pthread_mutex_destroy(&mutex_);
   }
 
   // Notifies all threads created with this notification to start. Must
   // be called from the controller thread.
   void Notify() {
     pthread_mutex_lock(&mutex_);
     notified_ = true;
     pthread_mutex_unlock(&mutex_);
   }
 
   // Blocks until the controller thread notifies. Must be called from a test
   // thread.
   void WaitForNotification() {
     for (;;) {
       pthread_mutex_lock(&mutex_);
       const bool notified = notified_;
       pthread_mutex_unlock(&mutex_);
       if (notified)
         break;
       SleepMilliseconds(10);
     }
   }
 
  private:
   pthread_mutex_t mutex_;
   bool notified_;
 
   GTEST_DISALLOW_COPY_AND_ASSIGN_(Notification);
 };
 
 # elif GTEST_OS_WINDOWS && !GTEST_OS_WINDOWS_PHONE && !GTEST_OS_WINDOWS_RT
 
 GTEST_API_ void SleepMilliseconds(int n);
 
 // Provides leak-safe Windows kernel handle ownership.
 // Used in death tests and in threading support.
 class GTEST_API_ AutoHandle {
  public:
   // Assume that Win32 HANDLE type is equivalent to void*. Doing so allows us to
   // avoid including <windows.h> in this header file. Including <windows.h> is
   // undesirable because it defines a lot of symbols and macros that tend to
   // conflict with client code. This assumption is verified by
   // WindowsTypesTest.HANDLEIsVoidStar.
   typedef void* Handle;
   AutoHandle();
   explicit AutoHandle(Handle handle);
 
   ~AutoHandle();
 
   Handle Get() const;
   void Reset();
   void Reset(Handle handle);
 
  private:
   // Returns true if and only if the handle is a valid handle object that can be
   // closed.
   bool IsCloseable() const;
 
   Handle handle_;
 
   GTEST_DISALLOW_COPY_AND_ASSIGN_(AutoHandle);
 };
 
 // Allows a controller thread to pause execution of newly created
 // threads until notified.  Instances of this class must be created
 // and destroyed in the controller thread.
 //
 // This class is only for testing Google Test's own constructs. Do not
 // use it in user tests, either directly or indirectly.
 class GTEST_API_ Notification {
  public:
   Notification();
   void Notify();
   void WaitForNotification();
 
  private:
   AutoHandle event_;
 
   GTEST_DISALLOW_COPY_AND_ASSIGN_(Notification);
 };
 # endif  // GTEST_HAS_NOTIFICATION_
 
 // On MinGW, we can have both GTEST_OS_WINDOWS and GTEST_HAS_PTHREAD
 // defined, but we don't want to use MinGW's pthreads implementation, which
 // has conformance problems with some versions of the POSIX standard.
 # if GTEST_HAS_PTHREAD && !GTEST_OS_WINDOWS_MINGW
 
 // As a C-function, ThreadFuncWithCLinkage cannot be templated itself.
 // Consequently, it cannot select a correct instantiation of ThreadWithParam
 // in order to call its Run(). Introducing ThreadWithParamBase as a
 // non-templated base class for ThreadWithParam allows us to bypass this
 // problem.
 class ThreadWithParamBase {
  public:
   virtual ~ThreadWithParamBase() {}
   virtual void Run() = 0;
 };
 
 // pthread_create() accepts a pointer to a function type with the C linkage.
 // According to the Standard (7.5/1), function types with different linkages
 // are different even if they are otherwise identical.  Some compilers (for
 // example, SunStudio) treat them as different types.  Since class methods
 // cannot be defined with C-linkage we need to define a free C-function to
 // pass into pthread_create().
 extern "C" inline void* ThreadFuncWithCLinkage(void* thread) {
   static_cast<ThreadWithParamBase*>(thread)->Run();
   return nullptr;
 }
 
 // Helper class for testing Google Test's multi-threading constructs.
 // To use it, write:
 //
 //   void ThreadFunc(int param) { /* Do things with param */ }
 //   Notification thread_can_start;
 //   ...
 //   // The thread_can_start parameter is optional; you can supply NULL.
 //   ThreadWithParam<int> thread(&ThreadFunc, 5, &thread_can_start);
 //   thread_can_start.Notify();
 //
 // These classes are only for testing Google Test's own constructs. Do
 // not use them in user tests, either directly or indirectly.
 template <typename T>
 class ThreadWithParam : public ThreadWithParamBase {
  public:
   typedef void UserThreadFunc(T);
 
   ThreadWithParam(UserThreadFunc* func, T param, Notification* thread_can_start)
       : func_(func),
         param_(param),
         thread_can_start_(thread_can_start),
         finished_(false) {
     ThreadWithParamBase* const base = this;
     // The thread can be created only after all fields except thread_
     // have been initialized.
     GTEST_CHECK_POSIX_SUCCESS_(
         pthread_create(&thread_, nullptr, &ThreadFuncWithCLinkage, base));
   }
   ~ThreadWithParam() override { Join(); }
 
   void Join() {
     if (!finished_) {
       GTEST_CHECK_POSIX_SUCCESS_(pthread_join(thread_, nullptr));
       finished_ = true;
     }
   }
 
   void Run() override {
     if (thread_can_start_ != nullptr) thread_can_start_->WaitForNotification();
     func_(param_);
   }
 
  private:
   UserThreadFunc* const func_;  // User-supplied thread function.
   const T param_;  // User-supplied parameter to the thread function.
   // When non-NULL, used to block execution until the controller thread
   // notifies.
   Notification* const thread_can_start_;
   bool finished_;  // true if and only if we know that the thread function has
                    // finished.
   pthread_t thread_;  // The native thread object.
 
   GTEST_DISALLOW_COPY_AND_ASSIGN_(ThreadWithParam);
 };
 # endif  // !GTEST_OS_WINDOWS && GTEST_HAS_PTHREAD ||
          // GTEST_HAS_MUTEX_AND_THREAD_LOCAL_
 
 # if GTEST_HAS_MUTEX_AND_THREAD_LOCAL_
 // Mutex and ThreadLocal have already been imported into the namespace.
 // Nothing to do here.
 
 # elif GTEST_OS_WINDOWS && !GTEST_OS_WINDOWS_PHONE && !GTEST_OS_WINDOWS_RT
 
 // Mutex implements mutex on Windows platforms.  It is used in conjunction
 // with class MutexLock:
 //
 //   Mutex mutex;
 //   ...
 //   MutexLock lock(&mutex);  // Acquires the mutex and releases it at the
 //                            // end of the current scope.
 //
 // A static Mutex *must* be defined or declared using one of the following
 // macros:
 //   GTEST_DEFINE_STATIC_MUTEX_(g_some_mutex);
 //   GTEST_DECLARE_STATIC_MUTEX_(g_some_mutex);
 //
 // (A non-static Mutex is defined/declared in the usual way).
 class GTEST_API_ Mutex {
  public:
   enum MutexType { kStatic = 0, kDynamic = 1 };
   // We rely on kStaticMutex being 0 as it is to what the linker initializes
   // type_ in static mutexes.  critical_section_ will be initialized lazily
   // in ThreadSafeLazyInit().
   enum StaticConstructorSelector { kStaticMutex = 0 };
 
   // This constructor intentionally does nothing.  It relies on type_ being
   // statically initialized to 0 (effectively setting it to kStatic) and on
   // ThreadSafeLazyInit() to lazily initialize the rest of the members.
   explicit Mutex(StaticConstructorSelector /*dummy*/) {}
 
   Mutex();
   ~Mutex();
 
   void Lock();
 
   void Unlock();
 
   // Does nothing if the current thread holds the mutex. Otherwise, crashes
   // with high probability.
   void AssertHeld();
 
  private:
   // Initializes owner_thread_id_ and critical_section_ in static mutexes.
   void ThreadSafeLazyInit();
 
   // Per https://blogs.msdn.microsoft.com/oldnewthing/20040223-00/?p=40503,
   // we assume that 0 is an invalid value for thread IDs.
   unsigned int owner_thread_id_;
 
   // For static mutexes, we rely on these members being initialized to zeros
   // by the linker.
   MutexType type_;
   long critical_section_init_phase_;  // NOLINT
   GTEST_CRITICAL_SECTION* critical_section_;
 
   GTEST_DISALLOW_COPY_AND_ASSIGN_(Mutex);
 };
 
 # define GTEST_DECLARE_STATIC_MUTEX_(mutex) \
     extern ::testing::internal::Mutex mutex
 
 # define GTEST_DEFINE_STATIC_MUTEX_(mutex) \
     ::testing::internal::Mutex mutex(::testing::internal::Mutex::kStaticMutex)
 
 // We cannot name this class MutexLock because the ctor declaration would
 // conflict with a macro named MutexLock, which is defined on some
 // platforms. That macro is used as a defensive measure to prevent against
 // inadvertent misuses of MutexLock like "MutexLock(&mu)" rather than
 // "MutexLock l(&mu)".  Hence the typedef trick below.
 class GTestMutexLock {
  public:
   explicit GTestMutexLock(Mutex* mutex)
       : mutex_(mutex) { mutex_->Lock(); }
 
   ~GTestMutexLock() { mutex_->Unlock(); }
 
  private:
   Mutex* const mutex_;
 
   GTEST_DISALLOW_COPY_AND_ASSIGN_(GTestMutexLock);
 };
 
 typedef GTestMutexLock MutexLock;
 
 // Base class for ValueHolder<T>.  Allows a caller to hold and delete a value
 // without knowing its type.
 class ThreadLocalValueHolderBase {
  public:
   virtual ~ThreadLocalValueHolderBase() {}
 };
 
 // Provides a way for a thread to send notifications to a ThreadLocal
 // regardless of its parameter type.
 class ThreadLocalBase {
  public:
   // Creates a new ValueHolder<T> object holding a default value passed to
   // this ThreadLocal<T>'s constructor and returns it.  It is the caller's
   // responsibility not to call this when the ThreadLocal<T> instance already
   // has a value on the current thread.
   virtual ThreadLocalValueHolderBase* NewValueForCurrentThread() const = 0;
 
  protected:
   ThreadLocalBase() {}
   virtual ~ThreadLocalBase() {}
 
  private:
   GTEST_DISALLOW_COPY_AND_ASSIGN_(ThreadLocalBase);
 };
 
 // Maps a thread to a set of ThreadLocals that have values instantiated on that
 // thread and notifies them when the thread exits.  A ThreadLocal instance is
 // expected to persist until all threads it has values on have terminated.
 class GTEST_API_ ThreadLocalRegistry {
  public:
   // Registers thread_local_instance as having value on the current thread.
   // Returns a value that can be used to identify the thread from other threads.
   static ThreadLocalValueHolderBase* GetValueOnCurrentThread(
       const ThreadLocalBase* thread_local_instance);
 
   // Invoked when a ThreadLocal instance is destroyed.
   static void OnThreadLocalDestroyed(
       const ThreadLocalBase* thread_local_instance);
 };
 
 class GTEST_API_ ThreadWithParamBase {
  public:
   void Join();
 
  protected:
   class Runnable {
    public:
     virtual ~Runnable() {}
     virtual void Run() = 0;
   };
 
   ThreadWithParamBase(Runnable *runnable, Notification* thread_can_start);
   virtual ~ThreadWithParamBase();
 
  private:
   AutoHandle thread_;
 };
 
 // Helper class for testing Google Test's multi-threading constructs.
 template <typename T>
 class ThreadWithParam : public ThreadWithParamBase {
  public:
   typedef void UserThreadFunc(T);
 
   ThreadWithParam(UserThreadFunc* func, T param, Notification* thread_can_start)
       : ThreadWithParamBase(new RunnableImpl(func, param), thread_can_start) {
   }
   virtual ~ThreadWithParam() {}
 
  private:
   class RunnableImpl : public Runnable {
    public:
     RunnableImpl(UserThreadFunc* func, T param)
         : func_(func),
           param_(param) {
     }
     virtual ~RunnableImpl() {}
     virtual void Run() {
       func_(param_);
     }
 
    private:
     UserThreadFunc* const func_;
     const T param_;
 
     GTEST_DISALLOW_COPY_AND_ASSIGN_(RunnableImpl);
   };
 
   GTEST_DISALLOW_COPY_AND_ASSIGN_(ThreadWithParam);
 };
 
 // Implements thread-local storage on Windows systems.
 //
 //   // Thread 1
 //   ThreadLocal<int> tl(100);  // 100 is the default value for each thread.
 //
 //   // Thread 2
 //   tl.set(150);  // Changes the value for thread 2 only.
 //   EXPECT_EQ(150, tl.get());
 //
 //   // Thread 1
 //   EXPECT_EQ(100, tl.get());  // In thread 1, tl has the original value.
 //   tl.set(200);
 //   EXPECT_EQ(200, tl.get());
 //
 // The template type argument T must have a public copy constructor.
 // In addition, the default ThreadLocal constructor requires T to have
 // a public default constructor.
 //
 // The users of a TheadLocal instance have to make sure that all but one
 // threads (including the main one) using that instance have exited before
 // destroying it. Otherwise, the per-thread objects managed for them by the
 // ThreadLocal instance are not guaranteed to be destroyed on all platforms.
 //
 // Google Test only uses global ThreadLocal objects.  That means they
 // will die after main() has returned.  Therefore, no per-thread
 // object managed by Google Test will be leaked as long as all threads
 // using Google Test have exited when main() returns.
 template <typename T>
 class ThreadLocal : public ThreadLocalBase {
  public:
   ThreadLocal() : default_factory_(new DefaultValueHolderFactory()) {}
   explicit ThreadLocal(const T& value)
       : default_factory_(new InstanceValueHolderFactory(value)) {}
 
   ~ThreadLocal() { ThreadLocalRegistry::OnThreadLocalDestroyed(this); }
 
   T* pointer() { return GetOrCreateValue(); }
   const T* pointer() const { return GetOrCreateValue(); }
   const T& get() const { return *pointer(); }
   void set(const T& value) { *pointer() = value; }
 
  private:
   // Holds a value of T.  Can be deleted via its base class without the caller
   // knowing the type of T.
   class ValueHolder : public ThreadLocalValueHolderBase {
    public:
     ValueHolder() : value_() {}
     explicit ValueHolder(const T& value) : value_(value) {}
 
     T* pointer() { return &value_; }
 
    private:
     T value_;
     GTEST_DISALLOW_COPY_AND_ASSIGN_(ValueHolder);
   };
 
 
   T* GetOrCreateValue() const {
     return static_cast<ValueHolder*>(
         ThreadLocalRegistry::GetValueOnCurrentThread(this))->pointer();
   }
 
   virtual ThreadLocalValueHolderBase* NewValueForCurrentThread() const {
     return default_factory_->MakeNewHolder();
   }
 
   class ValueHolderFactory {
    public:
     ValueHolderFactory() {}
     virtual ~ValueHolderFactory() {}
     virtual ValueHolder* MakeNewHolder() const = 0;
 
    private:
     GTEST_DISALLOW_COPY_AND_ASSIGN_(ValueHolderFactory);
   };
 
   class DefaultValueHolderFactory : public ValueHolderFactory {
    public:
     DefaultValueHolderFactory() {}
     ValueHolder* MakeNewHolder() const override { return new ValueHolder(); }
 
    private:
     GTEST_DISALLOW_COPY_AND_ASSIGN_(DefaultValueHolderFactory);
   };
 
   class InstanceValueHolderFactory : public ValueHolderFactory {
    public:
     explicit InstanceValueHolderFactory(const T& value) : value_(value) {}
     ValueHolder* MakeNewHolder() const override {
       return new ValueHolder(value_);
     }
 
    private:
     const T value_;  // The value for each thread.
 
     GTEST_DISALLOW_COPY_AND_ASSIGN_(InstanceValueHolderFactory);
   };
 
   std::unique_ptr<ValueHolderFactory> default_factory_;
 
   GTEST_DISALLOW_COPY_AND_ASSIGN_(ThreadLocal);
 };
 
 # elif GTEST_HAS_PTHREAD
 
 // MutexBase and Mutex implement mutex on pthreads-based platforms.
 class MutexBase {
  public:
   // Acquires this mutex.
   void Lock() {
     GTEST_CHECK_POSIX_SUCCESS_(pthread_mutex_lock(&mutex_));
     owner_ = pthread_self();
     has_owner_ = true;
   }
 
   // Releases this mutex.
   void Unlock() {
     // Since the lock is being released the owner_ field should no longer be
     // considered valid. We don't protect writing to has_owner_ here, as it's
     // the caller's responsibility to ensure that the current thread holds the
     // mutex when this is called.
     has_owner_ = false;
     GTEST_CHECK_POSIX_SUCCESS_(pthread_mutex_unlock(&mutex_));
   }
 
   // Does nothing if the current thread holds the mutex. Otherwise, crashes
   // with high probability.
   void AssertHeld() const {
     GTEST_CHECK_(has_owner_ && pthread_equal(owner_, pthread_self()))
         << "The current thread is not holding the mutex @" << this;
   }
 
   // A static mutex may be used before main() is entered.  It may even
   // be used before the dynamic initialization stage.  Therefore we
   // must be able to initialize a static mutex object at link time.
   // This means MutexBase has to be a POD and its member variables
   // have to be public.
  public:
   pthread_mutex_t mutex_;  // The underlying pthread mutex.
   // has_owner_ indicates whether the owner_ field below contains a valid thread
   // ID and is therefore safe to inspect (e.g., to use in pthread_equal()). All
   // accesses to the owner_ field should be protected by a check of this field.
   // An alternative might be to memset() owner_ to all zeros, but there's no
   // guarantee that a zero'd pthread_t is necessarily invalid or even different
   // from pthread_self().
   bool has_owner_;
   pthread_t owner_;  // The thread holding the mutex.
 };
 
 // Forward-declares a static mutex.
 #  define GTEST_DECLARE_STATIC_MUTEX_(mutex) \
      extern ::testing::internal::MutexBase mutex
 
 // Defines and statically (i.e. at link time) initializes a static mutex.
 // The initialization list here does not explicitly initialize each field,
 // instead relying on default initialization for the unspecified fields. In
 // particular, the owner_ field (a pthread_t) is not explicitly initialized.
 // This allows initialization to work whether pthread_t is a scalar or struct.
 // The flag -Wmissing-field-initializers must not be specified for this to work.
 #define GTEST_DEFINE_STATIC_MUTEX_(mutex) \
   ::testing::internal::MutexBase mutex = {PTHREAD_MUTEX_INITIALIZER, false, 0}
 
 // The Mutex class can only be used for mutexes created at runtime. It
 // shares its API with MutexBase otherwise.
 class Mutex : public MutexBase {
  public:
   Mutex() {
     GTEST_CHECK_POSIX_SUCCESS_(pthread_mutex_init(&mutex_, nullptr));
     has_owner_ = false;
   }
   ~Mutex() {
     GTEST_CHECK_POSIX_SUCCESS_(pthread_mutex_destroy(&mutex_));
   }
 
  private:
   GTEST_DISALLOW_COPY_AND_ASSIGN_(Mutex);
 };
 
 // We cannot name this class MutexLock because the ctor declaration would
 // conflict with a macro named MutexLock, which is defined on some
 // platforms. That macro is used as a defensive measure to prevent against
 // inadvertent misuses of MutexLock like "MutexLock(&mu)" rather than
 // "MutexLock l(&mu)".  Hence the typedef trick below.
 class GTestMutexLock {
  public:
   explicit GTestMutexLock(MutexBase* mutex)
       : mutex_(mutex) { mutex_->Lock(); }
 
   ~GTestMutexLock() { mutex_->Unlock(); }
 
  private:
   MutexBase* const mutex_;
 
   GTEST_DISALLOW_COPY_AND_ASSIGN_(GTestMutexLock);
 };
 
 typedef GTestMutexLock MutexLock;
 
 // Helpers for ThreadLocal.
 
 // pthread_key_create() requires DeleteThreadLocalValue() to have
 // C-linkage.  Therefore it cannot be templatized to access
 // ThreadLocal<T>.  Hence the need for class
 // ThreadLocalValueHolderBase.
 class ThreadLocalValueHolderBase {
  public:
   virtual ~ThreadLocalValueHolderBase() {}
 };
 
 // Called by pthread to delete thread-local data stored by
 // pthread_setspecific().
 extern "C" inline void DeleteThreadLocalValue(void* value_holder) {
   delete static_cast<ThreadLocalValueHolderBase*>(value_holder);
 }
 
 // Implements thread-local storage on pthreads-based systems.
 template <typename T>
 class GTEST_API_ ThreadLocal {
  public:
   ThreadLocal()
       : key_(CreateKey()), default_factory_(new DefaultValueHolderFactory()) {}
   explicit ThreadLocal(const T& value)
       : key_(CreateKey()),
         default_factory_(new InstanceValueHolderFactory(value)) {}
 
   ~ThreadLocal() {
     // Destroys the managed object for the current thread, if any.
     DeleteThreadLocalValue(pthread_getspecific(key_));
 
     // Releases resources associated with the key.  This will *not*
     // delete managed objects for other threads.
     GTEST_CHECK_POSIX_SUCCESS_(pthread_key_delete(key_));
   }
 
   T* pointer() { return GetOrCreateValue(); }
   const T* pointer() const { return GetOrCreateValue(); }
   const T& get() const { return *pointer(); }
   void set(const T& value) { *pointer() = value; }
 
  private:
   // Holds a value of type T.
   class ValueHolder : public ThreadLocalValueHolderBase {
    public:
     ValueHolder() : value_() {}
     explicit ValueHolder(const T& value) : value_(value) {}
 
     T* pointer() { return &value_; }
 
    private:
     T value_;
     GTEST_DISALLOW_COPY_AND_ASSIGN_(ValueHolder);
   };
 
   static pthread_key_t CreateKey() {
     pthread_key_t key;
     // When a thread exits, DeleteThreadLocalValue() will be called on
     // the object managed for that thread.
     GTEST_CHECK_POSIX_SUCCESS_(
         pthread_key_create(&key, &DeleteThreadLocalValue));
     return key;
   }
 
   T* GetOrCreateValue() const {
     ThreadLocalValueHolderBase* const holder =
         static_cast<ThreadLocalValueHolderBase*>(pthread_getspecific(key_));
     if (holder != nullptr) {
       return CheckedDowncastToActualType<ValueHolder>(holder)->pointer();
     }
 
     ValueHolder* const new_holder = default_factory_->MakeNewHolder();
     ThreadLocalValueHolderBase* const holder_base = new_holder;
     GTEST_CHECK_POSIX_SUCCESS_(pthread_setspecific(key_, holder_base));
     return new_holder->pointer();
   }
 
   class ValueHolderFactory {
    public:
     ValueHolderFactory() {}
     virtual ~ValueHolderFactory() {}
     virtual ValueHolder* MakeNewHolder() const = 0;
 
    private:
     GTEST_DISALLOW_COPY_AND_ASSIGN_(ValueHolderFactory);
   };
 
   class DefaultValueHolderFactory : public ValueHolderFactory {
    public:
     DefaultValueHolderFactory() {}
     ValueHolder* MakeNewHolder() const override { return new ValueHolder(); }
 
    private:
     GTEST_DISALLOW_COPY_AND_ASSIGN_(DefaultValueHolderFactory);
   };
 
   class InstanceValueHolderFactory : public ValueHolderFactory {
    public:
     explicit InstanceValueHolderFactory(const T& value) : value_(value) {}
     ValueHolder* MakeNewHolder() const override {
       return new ValueHolder(value_);
     }
 
    private:
     const T value_;  // The value for each thread.
 
     GTEST_DISALLOW_COPY_AND_ASSIGN_(InstanceValueHolderFactory);
   };
 
   // A key pthreads uses for looking up per-thread values.
   const pthread_key_t key_;
   std::unique_ptr<ValueHolderFactory> default_factory_;
 
   GTEST_DISALLOW_COPY_AND_ASSIGN_(ThreadLocal);
 };
 
 # endif  // GTEST_HAS_MUTEX_AND_THREAD_LOCAL_
 
 #else  // GTEST_IS_THREADSAFE
 
 // A dummy implementation of synchronization primitives (mutex, lock,
 // and thread-local variable).  Necessary for compiling Google Test where
 // mutex is not supported - using Google Test in multiple threads is not
 // supported on such platforms.
 
 class Mutex {
  public:
   Mutex() {}
   void Lock() {}
   void Unlock() {}
   void AssertHeld() const {}
 };
 
 # define GTEST_DECLARE_STATIC_MUTEX_(mutex) \
   extern ::testing::internal::Mutex mutex
 
 # define GTEST_DEFINE_STATIC_MUTEX_(mutex) ::testing::internal::Mutex mutex
 
 // We cannot name this class MutexLock because the ctor declaration would
 // conflict with a macro named MutexLock, which is defined on some
 // platforms. That macro is used as a defensive measure to prevent against
 // inadvertent misuses of MutexLock like "MutexLock(&mu)" rather than
 // "MutexLock l(&mu)".  Hence the typedef trick below.
 class GTestMutexLock {
  public:
   explicit GTestMutexLock(Mutex*) {}  // NOLINT
 };
 
 typedef GTestMutexLock MutexLock;
 
 template <typename T>
 class GTEST_API_ ThreadLocal {
  public:
   ThreadLocal() : value_() {}
   explicit ThreadLocal(const T& value) : value_(value) {}
   T* pointer() { return &value_; }
   const T* pointer() const { return &value_; }
   const T& get() const { return value_; }
   void set(const T& value) { value_ = value; }
  private:
   T value_;
 };
 
 #endif  // GTEST_IS_THREADSAFE
 
 // Returns the number of threads running in the process, or 0 to indicate that
 // we cannot detect it.
 GTEST_API_ size_t GetThreadCount();
 
 #if GTEST_OS_WINDOWS
 # define GTEST_PATH_SEP_ "\\"
 # define GTEST_HAS_ALT_PATH_SEP_ 1
 #else
 # define GTEST_PATH_SEP_ "/"
 # define GTEST_HAS_ALT_PATH_SEP_ 0
 #endif  // GTEST_OS_WINDOWS
 
 // Utilities for char.
 
 // isspace(int ch) and friends accept an unsigned char or EOF.  char
 // may be signed, depending on the compiler (or compiler flags).
 // Therefore we need to cast a char to unsigned char before calling
 // isspace(), etc.
 
 inline bool IsAlpha(char ch) {
   return isalpha(static_cast<unsigned char>(ch)) != 0;
 }
 inline bool IsAlNum(char ch) {
   return isalnum(static_cast<unsigned char>(ch)) != 0;
 }
 inline bool IsDigit(char ch) {
   return isdigit(static_cast<unsigned char>(ch)) != 0;
 }
 inline bool IsLower(char ch) {
   return islower(static_cast<unsigned char>(ch)) != 0;
 }
 inline bool IsSpace(char ch) {
   return isspace(static_cast<unsigned char>(ch)) != 0;
 }
 inline bool IsUpper(char ch) {
   return isupper(static_cast<unsigned char>(ch)) != 0;
 }
 inline bool IsXDigit(char ch) {
   return isxdigit(static_cast<unsigned char>(ch)) != 0;
 }
 inline bool IsXDigit(wchar_t ch) {
   const unsigned char low_byte = static_cast<unsigned char>(ch);
   return ch == low_byte && isxdigit(low_byte) != 0;
 }
 
 inline char ToLower(char ch) {
   return static_cast<char>(tolower(static_cast<unsigned char>(ch)));
 }
 inline char ToUpper(char ch) {
   return static_cast<char>(toupper(static_cast<unsigned char>(ch)));
 }
 
 inline std::string StripTrailingSpaces(std::string str) {
   std::string::iterator it = str.end();
   while (it != str.begin() && IsSpace(*--it))
     it = str.erase(it);
   return str;
 }
 
 // The testing::internal::posix namespace holds wrappers for common
 // POSIX functions.  These wrappers hide the differences between
 // Windows/MSVC and POSIX systems.  Since some compilers define these
 // standard functions as macros, the wrapper cannot have the same name
 // as the wrapped function.
 
 namespace posix {
 
 // Functions with a different name on Windows.
 
 #if GTEST_OS_WINDOWS
 
 typedef struct _stat StatStruct;
 
 # ifdef __BORLANDC__
 inline int DoIsATTY(int fd) { return isatty(fd); }
 inline int StrCaseCmp(const char* s1, const char* s2) {
   return stricmp(s1, s2);
 }
 inline char* StrDup(const char* src) { return strdup(src); }
 # else  // !__BORLANDC__
 #  if GTEST_OS_WINDOWS_MOBILE
 inline int DoIsATTY(int /* fd */) { return 0; }
 #  else
 inline int DoIsATTY(int fd) { return _isatty(fd); }
 #  endif  // GTEST_OS_WINDOWS_MOBILE
 inline int StrCaseCmp(const char* s1, const char* s2) {
   return _stricmp(s1, s2);
 }
 inline char* StrDup(const char* src) { return _strdup(src); }
 # endif  // __BORLANDC__
 
 # if GTEST_OS_WINDOWS_MOBILE
 inline int FileNo(FILE* file) { return reinterpret_cast<int>(_fileno(file)); }
 // Stat(), RmDir(), and IsDir() are not needed on Windows CE at this
 // time and thus not defined there.
 # else
 inline int FileNo(FILE* file) { return _fileno(file); }
 inline int Stat(const char* path, StatStruct* buf) { return _stat(path, buf); }
 inline int RmDir(const char* dir) { return _rmdir(dir); }
 inline bool IsDir(const StatStruct& st) {
   return (_S_IFDIR & st.st_mode) != 0;
 }
 # endif  // GTEST_OS_WINDOWS_MOBILE
 
 #elif GTEST_OS_ESP8266
 typedef struct stat StatStruct;
 
 inline int FileNo(FILE* file) { return fileno(file); }
 inline int DoIsATTY(int fd) { return isatty(fd); }
 inline int Stat(const char* path, StatStruct* buf) {
   // stat function not implemented on ESP8266
   return 0;
 }
 inline int StrCaseCmp(const char* s1, const char* s2) {
   return strcasecmp(s1, s2);
 }
 inline char* StrDup(const char* src) { return strdup(src); }
 inline int RmDir(const char* dir) { return rmdir(dir); }
 inline bool IsDir(const StatStruct& st) { return S_ISDIR(st.st_mode); }
 
 #else
 
 typedef struct stat StatStruct;
 
 inline int FileNo(FILE* file) { return fileno(file); }
 inline int DoIsATTY(int fd) { return isatty(fd); }
 inline int Stat(const char* path, StatStruct* buf) { return stat(path, buf); }
 inline int StrCaseCmp(const char* s1, const char* s2) {
   return strcasecmp(s1, s2);
 }
 inline char* StrDup(const char* src) { return strdup(src); }
 inline int RmDir(const char* dir) { return rmdir(dir); }
 inline bool IsDir(const StatStruct& st) { return S_ISDIR(st.st_mode); }
 
 #endif  // GTEST_OS_WINDOWS
 
 inline int IsATTY(int fd) {
   // DoIsATTY might change errno (for example ENOTTY in case you redirect stdout
   // to a file on Linux), which is unexpected, so save the previous value, and
   // restore it after the call.
   int savedErrno = errno;
   int isAttyValue = DoIsATTY(fd);
   errno = savedErrno;
 
   return isAttyValue;
 }
 
 // Functions deprecated by MSVC 8.0.
 
 GTEST_DISABLE_MSC_DEPRECATED_PUSH_()
 
 // ChDir(), FReopen(), FDOpen(), Read(), Write(), Close(), and
 // StrError() aren't needed on Windows CE at this time and thus not
 // defined there.
 
 #if !GTEST_OS_WINDOWS_MOBILE && !GTEST_OS_WINDOWS_PHONE && !GTEST_OS_WINDOWS_RT
 inline int ChDir(const char* dir) { return chdir(dir); }
 #endif
 inline FILE* FOpen(const char* path, const char* mode) {
   return fopen(path, mode);
 }
 #if !GTEST_OS_WINDOWS_MOBILE
 inline FILE *FReopen(const char* path, const char* mode, FILE* stream) {
   return freopen(path, mode, stream);
 }
 inline FILE* FDOpen(int fd, const char* mode) { return fdopen(fd, mode); }
 #endif
 inline int FClose(FILE* fp) { return fclose(fp); }
 #if !GTEST_OS_WINDOWS_MOBILE
 inline int Read(int fd, void* buf, unsigned int count) {
   return static_cast<int>(read(fd, buf, count));
 }
 inline int Write(int fd, const void* buf, unsigned int count) {
   return static_cast<int>(write(fd, buf, count));
 }
 inline int Close(int fd) { return close(fd); }
 inline const char* StrError(int errnum) { return strerror(errnum); }
 #endif
 inline const char* GetEnv(const char* name) {
 #if GTEST_OS_WINDOWS_MOBILE || GTEST_OS_WINDOWS_PHONE || \
     GTEST_OS_WINDOWS_RT || GTEST_OS_ESP8266
   // We are on an embedded platform, which has no environment variables.
   static_cast<void>(name);  // To prevent 'unused argument' warning.
   return nullptr;
 #elif defined(__BORLANDC__) || defined(__SunOS_5_8) || defined(__SunOS_5_9)
   // Environment variables which we programmatically clear will be set to the
   // empty string rather than unset (NULL).  Handle that case.
   const char* const env = getenv(name);
   return (env != nullptr && env[0] != '\0') ? env : nullptr;
 #else
   return getenv(name);
 #endif
 }
 
 GTEST_DISABLE_MSC_DEPRECATED_POP_()
 
 #if GTEST_OS_WINDOWS_MOBILE
 // Windows CE has no C library. The abort() function is used in
 // several places in Google Test. This implementation provides a reasonable
 // imitation of standard behaviour.
 [[noreturn]] void Abort();
 #else
 [[noreturn]] inline void Abort() { abort(); }
 #endif  // GTEST_OS_WINDOWS_MOBILE
 
 }  // namespace posix
 
 // MSVC "deprecates" snprintf and issues warnings wherever it is used.  In
 // order to avoid these warnings, we need to use _snprintf or _snprintf_s on
 // MSVC-based platforms.  We map the GTEST_SNPRINTF_ macro to the appropriate
 // function in order to achieve that.  We use macro definition here because
 // snprintf is a variadic function.
 #if _MSC_VER && !GTEST_OS_WINDOWS_MOBILE
 // MSVC 2005 and above support variadic macros.
 # define GTEST_SNPRINTF_(buffer, size, format, ...) \
      _snprintf_s(buffer, size, size, format, __VA_ARGS__)
 #elif defined(_MSC_VER)
 // Windows CE does not define _snprintf_s
 # define GTEST_SNPRINTF_ _snprintf
 #else
 # define GTEST_SNPRINTF_ snprintf
 #endif
 
 // The biggest signed integer type the compiler supports.
 //
 // long long is guaranteed to be at least 64-bits in C++11.
 using BiggestInt = long long;  // NOLINT
 
 // The maximum number a BiggestInt can represent.
 constexpr BiggestInt kMaxBiggestInt = (std::numeric_limits<BiggestInt>::max)();
 
 // This template class serves as a compile-time function from size to
 // type.  It maps a size in bytes to a primitive type with that
 // size. e.g.
 //
 //   TypeWithSize<4>::UInt
 //
 // is typedef-ed to be unsigned int (unsigned integer made up of 4
 // bytes).
 //
 // Such functionality should belong to STL, but I cannot find it
 // there.
 //
 // Google Test uses this class in the implementation of floating-point
 // comparison.
 //
 // For now it only handles UInt (unsigned int) as that's all Google Test
 // needs.  Other types can be easily added in the future if need
 // arises.
 template <size_t size>
 class TypeWithSize {
  public:
   // This prevents the user from using TypeWithSize<N> with incorrect
   // values of N.
   using UInt = void;
 };
 
 // The specialization for size 4.
 template <>
 class TypeWithSize<4> {
  public:
   using Int = std::int32_t;
   using UInt = std::uint32_t;
 };
 
 // The specialization for size 8.
 template <>
 class TypeWithSize<8> {
  public:
   using Int = std::int64_t;
   using UInt = std::uint64_t;
 };
 
 // Integer types of known sizes.
 using TimeInMillis = int64_t;  // Represents time in milliseconds.
 
 // Utilities for command line flags and environment variables.
 
 // Macro for referencing flags.
 #if !defined(GTEST_FLAG)
 # define GTEST_FLAG(name) FLAGS_gtest_##name
 #endif  // !defined(GTEST_FLAG)
 
 #if !defined(GTEST_USE_OWN_FLAGFILE_FLAG_)
 # define GTEST_USE_OWN_FLAGFILE_FLAG_ 1
 #endif  // !defined(GTEST_USE_OWN_FLAGFILE_FLAG_)
 
 #if !defined(GTEST_DECLARE_bool_)
 # define GTEST_FLAG_SAVER_ ::testing::internal::GTestFlagSaver
 
 // Macros for declaring flags.
 # define GTEST_DECLARE_bool_(name) GTEST_API_ extern bool GTEST_FLAG(name)
 # define GTEST_DECLARE_int32_(name) \
     GTEST_API_ extern std::int32_t GTEST_FLAG(name)
 # define GTEST_DECLARE_string_(name) \
     GTEST_API_ extern ::std::string GTEST_FLAG(name)
 
 // Macros for defining flags.
 # define GTEST_DEFINE_bool_(name, default_val, doc) \
     GTEST_API_ bool GTEST_FLAG(name) = (default_val)
 # define GTEST_DEFINE_int32_(name, default_val, doc) \
     GTEST_API_ std::int32_t GTEST_FLAG(name) = (default_val)
 # define GTEST_DEFINE_string_(name, default_val, doc) \
     GTEST_API_ ::std::string GTEST_FLAG(name) = (default_val)
 
 #endif  // !defined(GTEST_DECLARE_bool_)
 
 // Thread annotations
 #if !defined(GTEST_EXCLUSIVE_LOCK_REQUIRED_)
 # define GTEST_EXCLUSIVE_LOCK_REQUIRED_(locks)
 # define GTEST_LOCK_EXCLUDED_(locks)
 #endif  // !defined(GTEST_EXCLUSIVE_LOCK_REQUIRED_)
 
 // Parses 'str' for a 32-bit signed integer.  If successful, writes the result
 // to *value and returns true; otherwise leaves *value unchanged and returns
 // false.
 bool ParseInt32(const Message& src_text, const char* str, int32_t* value);
 
 // Parses a bool/int32_t/string from the environment variable
 // corresponding to the given Google Test flag.
 bool BoolFromGTestEnv(const char* flag, bool default_val);
 GTEST_API_ int32_t Int32FromGTestEnv(const char* flag, int32_t default_val);
 std::string OutputFlagAlsoCheckEnvVar();
 const char* StringFromGTestEnv(const char* flag, const char* default_val);
 
 }  // namespace internal
 }  // namespace testing
 
 #if !defined(GTEST_INTERNAL_DEPRECATED)
 
 // Internal Macro to mark an API deprecated, for googletest usage only
 // Usage: class GTEST_INTERNAL_DEPRECATED(message) MyClass or
 // GTEST_INTERNAL_DEPRECATED(message) <return_type> myFunction(); Every usage of
 // a deprecated entity will trigger a warning when compiled with
 // `-Wdeprecated-declarations` option (clang, gcc, any __GNUC__ compiler).
 // For msvc /W3 option will need to be used
 // Note that for 'other' compilers this macro evaluates to nothing to prevent
 // compilations errors.
 #if defined(_MSC_VER)
 #define GTEST_INTERNAL_DEPRECATED(message) __declspec(deprecated(message))
 #elif defined(__GNUC__)
 #define GTEST_INTERNAL_DEPRECATED(message) __attribute__((deprecated(message)))
 #else
 #define GTEST_INTERNAL_DEPRECATED(message)
 #endif
 
 #endif  // !defined(GTEST_INTERNAL_DEPRECATED)
 
 #if GTEST_HAS_ABSL
 // Always use absl::string_view for Matcher<> specializations if googletest
 // is built with absl support.
 # define GTEST_INTERNAL_HAS_STRING_VIEW 1
 #include "absl/strings/string_view.h"
 namespace testing {
 namespace internal {
 using StringView = ::absl::string_view;
 }  // namespace internal
 }  // namespace testing
 #else
 # ifdef __has_include
 #   if __has_include(<string_view>) && __cplusplus >= 201703L
 // Otherwise for C++17 and higher use std::string_view for Matcher<>
 // specializations.
 #   define GTEST_INTERNAL_HAS_STRING_VIEW 1
 #include <string_view>
 namespace testing {
 namespace internal {
 using StringView = ::std::string_view;
 }  // namespace internal
 }  // namespace testing
 // The case where absl is configured NOT to alias std::string_view is not
 // supported.
 #  endif  // __has_include(<string_view>) && __cplusplus >= 201703L
 # endif  // __has_include
 #endif  // GTEST_HAS_ABSL
 
 #endif  // GTEST_INCLUDE_GTEST_INTERNAL_GTEST_PORT_H_