From: Jonathan Wakely Date: Wed, 8 Dec 2021 20:58:11 +0000 (+0000) Subject: libstdc++: Implement std::ios_base::noreplace for C++23 [PR59769] X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=a219139e986a4200a9105d7c1fa63735d2945994;p=test_jj.git libstdc++: Implement std::ios_base::noreplace for C++23 [PR59769] This implements my P2467R0 proposal to support opening an fstream in exclusive mode. The new constant is also supported pre-C++23 as std::ios_base::__noreplace. This proposal hasn't been approved for C++23 yet, but I am confident it will be, as this is restoring a feture found in pre-ISO C++ iostreams implementations (and still present in the MSVC library as _Noreplace). If the proposal fails for C++23 we can remove the ios::noreplace name and just keep ios::__noreplace as an extension. libstdc++-v3/ChangeLog: PR libstdc++/59769 * config/io/basic_file_stdio.cc (fopen_mode): Add support for exclusive mode. * include/bits/ios_base.h (_S_noreplace): Define new enumerator. (ios_base::__noreplace): Define. (ios_base::noreplace): Define for C++23. * include/std/version (__cpp_lib_ios_noreplace): Define. * testsuite/27_io/basic_ofstream/open/char/noreplace.cc: New test. * testsuite/27_io/basic_ofstream/open/wchar_t/noreplace.cc: New test. --- diff --git a/libstdc++-v3/config/io/basic_file_stdio.cc b/libstdc++-v3/config/io/basic_file_stdio.cc index ce4a638..06ee016 100644 --- a/libstdc++-v3/config/io/basic_file_stdio.cc +++ b/libstdc++-v3/config/io/basic_file_stdio.cc @@ -78,32 +78,38 @@ namespace out = std::ios_base::out, trunc = std::ios_base::trunc, app = std::ios_base::app, - binary = std::ios_base::binary + binary = std::ios_base::binary, + noreplace = std::_S_noreplace }; // _GLIBCXX_RESOLVE_LIB_DEFECTS // 596. 27.8.1.3 Table 112 omits "a+" and "a+b" modes. - switch (mode & (in|out|trunc|app|binary)) + switch (mode & (in|out|trunc|app|binary|noreplace)) { - case ( out ): return "w"; - case ( out |app ): return "a"; - case ( app ): return "a"; - case ( out|trunc ): return "w"; - case (in ): return "r"; - case (in|out ): return "r+"; - case (in|out|trunc ): return "w+"; - case (in|out |app ): return "a+"; - case (in |app ): return "a+"; - - case ( out |binary): return "wb"; - case ( out |app|binary): return "ab"; - case ( app|binary): return "ab"; - case ( out|trunc |binary): return "wb"; - case (in |binary): return "rb"; - case (in|out |binary): return "r+b"; - case (in|out|trunc |binary): return "w+b"; - case (in|out |app|binary): return "a+b"; - case (in |app|binary): return "a+b"; + case ( out ): return "w"; + case ( out |noreplace): return "wx"; + case ( out|trunc ): return "w"; + case ( out|trunc |noreplace): return "wx"; + case ( out |app ): return "a"; + case ( app ): return "a"; + case (in ): return "r"; + case (in|out ): return "r+"; + case (in|out|trunc ): return "w+"; + case (in|out|trunc |noreplace): return "w+x"; + case (in|out |app ): return "a+"; + case (in |app ): return "a+"; + + case ( out |binary ): return "wb"; + case ( out |binary|noreplace): return "wbx"; + case ( out |app|binary ): return "ab"; + case ( app|binary ): return "ab"; + case ( out|trunc |binary ): return "wb"; + case (in |binary ): return "rb"; + case (in|out |binary ): return "r+b"; + case (in|out|trunc |binary ): return "w+b"; + case (in|out|trunc |binary|noreplace): return "w+bx"; + case (in|out |app|binary ): return "a+b"; + case (in |app|binary ): return "a+b"; default: return 0; // invalid } diff --git a/libstdc++-v3/include/bits/ios_base.h b/libstdc++-v3/include/bits/ios_base.h index d6626d4..5db0552 100644 --- a/libstdc++-v3/include/bits/ios_base.h +++ b/libstdc++-v3/include/bits/ios_base.h @@ -116,6 +116,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION _S_in = 1L << 3, _S_out = 1L << 4, _S_trunc = 1L << 5, + _S_noreplace = 1L << 6, _S_ios_openmode_end = 1L << 16, _S_ios_openmode_max = __INT_MAX__, _S_ios_openmode_min = ~__INT_MAX__ @@ -466,6 +467,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION /// Truncate an existing stream when opening. Default for @c ofstream. static const openmode trunc = _S_trunc; + static const openmode __noreplace = _S_noreplace; + +#if __cplusplus >= 202100L +#define __cpp_lib_ios_noreplace 202200L + /// Open a file in exclusive mode. + static const openmode noreplace = _S_noreplace; +#endif + // 27.4.2.1.5 Type ios_base::seekdir /** * @brief This is an enumerated type. diff --git a/libstdc++-v3/include/std/version b/libstdc++-v3/include/std/version index eb612f5..23890037 100644 --- a/libstdc++-v3/include/std/version +++ b/libstdc++-v3/include/std/version @@ -296,6 +296,7 @@ #define __cpp_lib_adaptor_iterator_pair_constructor 202106L #define __cpp_lib_byteswap 202110L #define __cpp_lib_invoke_r 202106L +#define __cpp_lib_ios_noreplace 202200L #define __cpp_lib_is_scoped_enum 202011L #if __cpp_lib_concepts # define __cpp_lib_monadic_optional 202110L diff --git a/libstdc++-v3/testsuite/27_io/basic_ofstream/open/char/noreplace.cc b/libstdc++-v3/testsuite/27_io/basic_ofstream/open/char/noreplace.cc new file mode 100644 index 0000000..e39f592 --- /dev/null +++ b/libstdc++-v3/testsuite/27_io/basic_ofstream/open/char/noreplace.cc @@ -0,0 +1,29 @@ +// { dg-do run } + +#include + +#if __cplusplus >= 202200L +#ifndef __cpp_lib_ios_noreplace +# error "Feature-test macro for ios::noreplace missing in " +#elif __cpp_lib_ios_noreplace < 202200L +# error "Feature-test macro for ios::noreplace has wrong value in " +#endif +#endif + +#include +#include + +int main() +{ +#if __cpp_lib_ios_noreplace + std::ios::openmode noreplace = std::ios::noreplace; +#else + std::ios::openmode noreplace = std::ios::__noreplace; +#endif + + std::ofstream of("noreplace"); + VERIFY( of.is_open() ); + of.close(); + of.open("noreplace", noreplace); + VERIFY( ! of.is_open() ); +} diff --git a/libstdc++-v3/testsuite/27_io/basic_ofstream/open/wchar_t/noreplace.cc b/libstdc++-v3/testsuite/27_io/basic_ofstream/open/wchar_t/noreplace.cc new file mode 100644 index 0000000..77f1186 --- /dev/null +++ b/libstdc++-v3/testsuite/27_io/basic_ofstream/open/wchar_t/noreplace.cc @@ -0,0 +1,29 @@ +// { dg-do run } + +#include + +#if __cplusplus >= 202200L +#ifndef __cpp_lib_ios_noreplace +# error "Feature-test macro for ios::noreplace missing in " +#elif __cpp_lib_ios_noreplace < 202200L +# error "Feature-test macro for ios::noreplace has wrong value in " +#endif +#endif + +#include +#include + +int main() +{ +#if __cpp_lib_ios_noreplace + std::wios::openmode noreplace = std::wios::noreplace; +#else + std::wios::openmode noreplace = std::wios::__noreplace; +#endif + + std::wofstream of("noreplace"); + VERIFY( of.is_open() ); + of.close(); + of.open("noreplace", noreplace); + VERIFY( ! of.is_open() ); +}