368faacac7
This commit reverts 5aaefa51 (and also partly 7f285f48e77 and b6d75682f9, which were related to the original commit). As landed, 5aaefa51 had unintended consequences on some downstream bots and didn't have proper coverage upstream due to a few subtle things. Implementing this is something we should do in libc++, however we'll first need to address a few issues listed in https://reviews.llvm.org/D106124#3349710. Differential Revision: https://reviews.llvm.org/D120683
110 lines
3.6 KiB
C++
110 lines
3.6 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___FORMAT_FORMAT_PARSE_CONTEXT_H
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#define _LIBCPP___FORMAT_FORMAT_PARSE_CONTEXT_H
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#include <__config>
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#include <__format/format_error.h>
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#include <string_view>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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#if _LIBCPP_STD_VER > 17
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// TODO FMT Remove this once we require compilers with proper C++20 support.
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// If the compiler has no concepts support, the format header will be disabled.
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// Without concepts support enable_if needs to be used and that too much effort
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// to support compilers with partial C++20 support.
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#if !defined(_LIBCPP_HAS_NO_CONCEPTS)
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template <class _CharT>
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class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT basic_format_parse_context {
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public:
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using char_type = _CharT;
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using const_iterator = typename basic_string_view<_CharT>::const_iterator;
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using iterator = const_iterator;
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_LIBCPP_HIDE_FROM_ABI
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constexpr explicit basic_format_parse_context(basic_string_view<_CharT> __fmt,
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size_t __num_args = 0) noexcept
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: __begin_(__fmt.begin()),
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__end_(__fmt.end()),
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__indexing_(__unknown),
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__next_arg_id_(0),
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__num_args_(__num_args) {}
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basic_format_parse_context(const basic_format_parse_context&) = delete;
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basic_format_parse_context&
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operator=(const basic_format_parse_context&) = delete;
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_LIBCPP_HIDE_FROM_ABI constexpr const_iterator begin() const noexcept {
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return __begin_;
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}
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_LIBCPP_HIDE_FROM_ABI constexpr const_iterator end() const noexcept {
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return __end_;
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}
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_LIBCPP_HIDE_FROM_ABI constexpr void advance_to(const_iterator __it) {
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__begin_ = __it;
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}
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_LIBCPP_HIDE_FROM_ABI constexpr size_t next_arg_id() {
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if (__indexing_ == __manual)
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__throw_format_error("Using automatic argument numbering in manual "
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"argument numbering mode");
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if (__indexing_ == __unknown)
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__indexing_ = __automatic;
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return __next_arg_id_++;
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}
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_LIBCPP_HIDE_FROM_ABI constexpr void check_arg_id(size_t __id) {
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if (__indexing_ == __automatic)
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__throw_format_error("Using manual argument numbering in automatic "
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"argument numbering mode");
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if (__indexing_ == __unknown)
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__indexing_ = __manual;
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// Throws an exception to make the expression a non core constant
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// expression as required by:
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// [format.parse.ctx]/11
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// Remarks: Call expressions where id >= num_args_ are not core constant
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// expressions ([expr.const]).
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// Note: the Throws clause [format.parse.ctx]/10 doesn't specify the
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// behavior when id >= num_args_.
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if (is_constant_evaluated() && __id >= __num_args_)
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__throw_format_error("Argument index outside the valid range");
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}
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private:
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iterator __begin_;
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iterator __end_;
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enum _Indexing { __unknown, __manual, __automatic };
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_Indexing __indexing_;
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size_t __next_arg_id_;
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size_t __num_args_;
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};
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using format_parse_context = basic_format_parse_context<char>;
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#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
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using wformat_parse_context = basic_format_parse_context<wchar_t>;
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#endif
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#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
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#endif //_LIBCPP_STD_VER > 17
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___FORMAT_FORMAT_PARSE_CONTEXT_H
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