From e3b557809604d036af6e00c60f012c2025b59a5e Mon Sep 17 00:00:00 2001 From: Dimitry Andric Date: Sat, 11 Feb 2023 13:38:04 +0100 Subject: Vendor import of llvm-project main llvmorg-16-init-18548-gb0daacf58f41, the last commit before the upstream release/17.x branch was created. --- libcxx/include/__format/formatter_tuple.h | 178 ++++++++++++++++++++++++++++++ 1 file changed, 178 insertions(+) create mode 100644 libcxx/include/__format/formatter_tuple.h (limited to 'libcxx/include/__format/formatter_tuple.h') diff --git a/libcxx/include/__format/formatter_tuple.h b/libcxx/include/__format/formatter_tuple.h new file mode 100644 index 000000000000..82f5ada6e012 --- /dev/null +++ b/libcxx/include/__format/formatter_tuple.h @@ -0,0 +1,178 @@ +// -*- 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 +#include + +#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 + _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(), [&] { + 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 + typename _FormatContext::iterator _LIBCPP_HIDE_FROM_ABI + format(conditional_t<(formattable && ...), 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>, _CharT>>{}); + + __format_tuple(__tuple, __c); + + return __formatter::__write_string_no_precision(basic_string_view{__str}, __ctx.out(), __specs); + } + + template + _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(), [&] { + 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, _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, _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, _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, _CharT> + : public __formatter_tuple<_CharT, pair<_Args...>, _Args...> {}; + +template <__fmt_char_type _CharT, formattable<_CharT>... _Args> +struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter, _CharT> + : public __formatter_tuple<_CharT, tuple<_Args...>, _Args...> {}; + +#endif //_LIBCPP_STD_VER > 20 + +_LIBCPP_END_NAMESPACE_STD + +#endif // _LIBCPP___FORMAT_FORMATTER_TUPLE_H -- cgit v1.2.3