| // -*- C++ -*- |
| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef _LIBCPP___FORMAT_FORMATTER_TUPLE_H |
| #define _LIBCPP___FORMAT_FORMATTER_TUPLE_H |
| |
| #include <__algorithm/ranges_copy.h> |
| #include <__availability> |
| #include <__chrono/statically_widen.h> |
| #include <__config> |
| #include <__format/concepts.h> |
| #include <__format/format_args.h> |
| #include <__format/format_context.h> |
| #include <__format/format_error.h> |
| #include <__format/format_parse_context.h> |
| #include <__format/formatter.h> |
| #include <__format/formatter_output.h> |
| #include <__format/parser_std_format_spec.h> |
| #include <__iterator/back_insert_iterator.h> |
| #include <__type_traits/remove_cvref.h> |
| #include <__utility/integer_sequence.h> |
| #include <__utility/pair.h> |
| #include <string_view> |
| #include <tuple> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| #if _LIBCPP_STD_VER > 20 |
| |
| template <__fmt_char_type _CharT, class _Tuple, formattable<_CharT>... _Args> |
| struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT __formatter_tuple { |
| _LIBCPP_HIDE_FROM_ABI constexpr void set_separator(basic_string_view<_CharT> __separator) { |
| __separator_ = __separator; |
| } |
| _LIBCPP_HIDE_FROM_ABI constexpr void |
| set_brackets(basic_string_view<_CharT> __opening_bracket, basic_string_view<_CharT> __closing_bracket) { |
| __opening_bracket_ = __opening_bracket; |
| __closing_bracket_ = __closing_bracket; |
| } |
| |
| template <class _ParseContext> |
| _LIBCPP_HIDE_FROM_ABI constexpr typename _ParseContext::iterator parse(_ParseContext& __parse_ctx) { |
| const _CharT* __begin = __parser_.__parse(__parse_ctx, __format_spec::__fields_tuple); |
| |
| // [format.tuple]/7 |
| // ... For each element e in underlying_, if e.set_debug_format() |
| // is a valid expression, calls e.set_debug_format(). |
| // TODO FMT this can be removed when P2733 is accepted. |
| std::__for_each_index_sequence(make_index_sequence<sizeof...(_Args)>(), [&]<size_t _Index> { |
| std::__set_debug_format(std::get<_Index>(__underlying_)); |
| }); |
| |
| const _CharT* __end = __parse_ctx.end(); |
| if (__begin == __end) |
| return __begin; |
| |
| if (*__begin == _CharT('m')) { |
| if constexpr (sizeof...(_Args) == 2) { |
| set_separator(_LIBCPP_STATICALLY_WIDEN(_CharT, ": ")); |
| set_brackets({}, {}); |
| ++__begin; |
| } else |
| std::__throw_format_error("The format specifier m requires a pair or a two-element tuple"); |
| } else if (*__begin == _CharT('n')) { |
| set_brackets({}, {}); |
| ++__begin; |
| } |
| |
| if (__begin != __end && *__begin != _CharT('}')) |
| std::__throw_format_error("The format-spec should consume the input or end with a '}'"); |
| |
| return __begin; |
| } |
| |
| template <class _FormatContext> |
| typename _FormatContext::iterator _LIBCPP_HIDE_FROM_ABI |
| format(conditional_t<(formattable<const _Args, _CharT> && ...), const _Tuple&, _Tuple&> __tuple, |
| _FormatContext& __ctx) const { |
| __format_spec::__parsed_specifications<_CharT> __specs = __parser_.__get_parsed_std_specifications(__ctx); |
| |
| if (!__specs.__has_width()) |
| return __format_tuple(__tuple, __ctx); |
| |
| basic_string<_CharT> __str; |
| |
| // Since the output is written to a different iterator a new context is |
| // created. Since the underlying formatter uses the default formatting it |
| // doesn't need a locale or the formatting arguments. So creating a new |
| // context works. |
| // |
| // This solution works for this formatter, but it will not work for the |
| // range_formatter. In that patch a generic solution is work in progress. |
| // Once that is finished it can be used here. (The range_formatter will use |
| // these features so it's easier to add it there and then port it.) |
| // |
| // TODO FMT Use formatting wrapping used in the range_formatter. |
| basic_format_context __c = std::__format_context_create( |
| back_insert_iterator{__str}, |
| basic_format_args<basic_format_context<back_insert_iterator<basic_string<_CharT>>, _CharT>>{}); |
| |
| __format_tuple(__tuple, __c); |
| |
| return __formatter::__write_string_no_precision(basic_string_view{__str}, __ctx.out(), __specs); |
| } |
| |
| template <class _FormatContext> |
| _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator __format_tuple(auto&& __tuple, _FormatContext& __ctx) const { |
| __ctx.advance_to(std::ranges::copy(__opening_bracket_, __ctx.out()).out); |
| |
| std::__for_each_index_sequence(make_index_sequence<sizeof...(_Args)>(), [&]<size_t _Index> { |
| if constexpr (_Index) |
| __ctx.advance_to(std::ranges::copy(__separator_, __ctx.out()).out); |
| |
| // During review Victor suggested to make the exposition only |
| // __underlying_ member a local variable. Currently the Standard |
| // requires nested debug-enabled formatter specializations not to |
| // output escaped output. P2733 fixes that bug, once accepted the |
| // code below can be used. |
| // (Note when a paper allows parsing a tuple-underlying-spec the |
| // exposition only member needs to be a class member. Earlier |
| // revisions of P2286 proposed that, but this was not pursued, |
| // due to time constrains and complexity of the matter.) |
| // TODO FMT This can be updated after P2733 is accepted. |
| # if 0 |
| // P2286 uses an exposition only member in the formatter |
| // tuple<formatter<remove_cvref_t<_Args>, _CharT>...> __underlying_; |
| // This was used in earlier versions of the paper since |
| // __underlying_.parse(...) was called. This is no longer the case |
| // so we can reduce the scope of the formatter. |
| // |
| // It does require the underlying's parse effect to be moved here too. |
| using _Arg = tuple_element<_Index, decltype(__tuple)>; |
| formatter<remove_cvref_t<_Args>, _CharT> __underlying; |
| |
| // [format.tuple]/7 |
| // ... For each element e in underlying_, if e.set_debug_format() |
| // is a valid expression, calls e.set_debug_format(). |
| std::__set_debug_format(__underlying); |
| # else |
| __ctx.advance_to(std::get<_Index>(__underlying_).format(std::get<_Index>(__tuple), __ctx)); |
| # endif |
| }); |
| |
| return std::ranges::copy(__closing_bracket_, __ctx.out()).out; |
| } |
| |
| __format_spec::__parser<_CharT> __parser_{.__alignment_ = __format_spec::__alignment::__left}; |
| |
| private: |
| tuple<formatter<remove_cvref_t<_Args>, _CharT>...> __underlying_; |
| basic_string_view<_CharT> __separator_ = _LIBCPP_STATICALLY_WIDEN(_CharT, ", "); |
| basic_string_view<_CharT> __opening_bracket_ = _LIBCPP_STATICALLY_WIDEN(_CharT, "("); |
| basic_string_view<_CharT> __closing_bracket_ = _LIBCPP_STATICALLY_WIDEN(_CharT, ")"); |
| }; |
| |
| template <__fmt_char_type _CharT, formattable<_CharT>... _Args> |
| struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<pair<_Args...>, _CharT> |
| : public __formatter_tuple<_CharT, pair<_Args...>, _Args...> {}; |
| |
| template <__fmt_char_type _CharT, formattable<_CharT>... _Args> |
| struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<tuple<_Args...>, _CharT> |
| : public __formatter_tuple<_CharT, tuple<_Args...>, _Args...> {}; |
| |
| #endif //_LIBCPP_STD_VER > 20 |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP___FORMAT_FORMATTER_TUPLE_H |