libcxx/include/__thread/formatter.h

   1 // -*- C++ -*-
   2 //===----------------------------------------------------------------------===//
   3 //
   4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   5 // See https://llvm.org/LICENSE.txt for license information.
   6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #ifndef _LIBCPP___THREAD_FORMATTER_H
  11 #define _LIBCPP___THREAD_FORMATTER_H
  12
  13 #include <__concepts/arithmetic.h>
  14 #include <__config>
  15 #include <__format/concepts.h>
  16 #include <__format/format_parse_context.h>
  17 #include <__format/formatter.h>
  18 #include <__format/formatter_integral.h>
  19 #include <__format/parser_std_format_spec.h>
  20 #include <__thread/id.h>
  21 #include <__type_traits/conditional.h>
  22 #include <__type_traits/is_pointer.h>
  23 #include <__type_traits/is_same.h>
  24 #include <cstdint>
  25
  26 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  27 #  pragma GCC system_header
  28 #endif
  29
  30 #if _LIBCPP_STD_VER >= 23
  31
  32 _LIBCPP_BEGIN_NAMESPACE_STD
  33
  34 #ifndef _LIBCPP_HAS_NO_THREADS
  35
  36 template <__fmt_char_type _CharT>
  37 struct _LIBCPP_TEMPLATE_VIS formatter<__thread_id, _CharT> {
  38   public:
  39     template <class _ParseContext>
  40     _LIBCPP_HIDE_FROM_ABI constexpr typename _ParseContext::iterator parse(_ParseContext& __ctx) {
  41         return __parser_.__parse(__ctx, __format_spec::__fields_fill_align_width);
  42     }
  43
  44     template <class _FormatContext>
  45     _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator format(__thread_id __id, _FormatContext& __ctx) const {
  46         // In __threading_support __libcpp_thread_id is either a
  47         // unsigned long long or a pthread_t.
  48         //
  49         // The type of pthread_t is left unspecified in POSIX so it can be any
  50         // type. The most logical types are an integral or pointer.
  51         // On Linux systems pthread_t is an unsigned long long.
  52         // On Apple systems pthread_t is a pointer type.
  53         //
  54         // Note the output should match what the stream operator does. Since
  55         // the ostream operator has been shipped years before this formatter
  56         // was added to the Standard, this formatter does what the stream
  57         // operator does. This may require platform specific changes.
  58
  59         using _Tp = decltype(__get_underlying_id(__id));
  60         using _Cp = conditional_t<integral<_Tp>, _Tp, conditional_t<is_pointer_v<_Tp>, uintptr_t, void>>;
  61         static_assert(!is_same_v<_Cp, void>, "unsupported thread::id type, please file a bug report");
  62
  63         __format_spec::__parsed_specifications<_CharT> __specs = __parser_.__get_parsed_std_specifications(__ctx);
  64         if constexpr (is_pointer_v<_Tp>) {
  65           __specs.__std_.__alternate_form_ = true;
  66           __specs.__std_.__type_           = __format_spec::__type::__hexadecimal_lower_case;
  67         }
  68         return __formatter::__format_integer(reinterpret_cast<_Cp>(__get_underlying_id(__id)), __ctx, __specs);
  69     }
  70
  71     __format_spec::__parser<_CharT> __parser_{.__alignment_ = __format_spec::__alignment::__right};
  72 };
  73
  74 #endif // !_LIBCPP_HAS_NO_THREADS
  75
  76 _LIBCPP_END_NAMESPACE_STD
  77
  78 #endif // _LIBCPP_STD_VER >= 23
  79
  80 #endif // _LIBCPP___THREAD_FORMATTER_H