48048c2f94
in to_string.hh, we define the specialization of
`fmt::formatter<std::optional<T>>`, which is available in {fmt} v10
and up. to avoid conditionally including `utils/to_string.hh` and
`fmt/std.h` in all source files formatting `std::optional<T>` using
{fmt}, let's include `fmt/std.h` if {fmt}'s verison is greater or equal
to 10. in future, we should drop the specialization and use `fmt/std.h`
directly.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closes scylladb/scylladb#18325
46 lines
1.2 KiB
C++
46 lines
1.2 KiB
C++
/*
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* Copyright (C) 2015-present ScyllaDB
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*/
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/*
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* SPDX-License-Identifier: AGPL-3.0-or-later
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*/
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#pragma once
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#include <fmt/format.h>
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#include <fmt/ostream.h>
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#if FMT_VERSION >= 100000
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#include <fmt/std.h>
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#else
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#include <optional>
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#endif
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#if FMT_VERSION < 100000
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template <typename T>
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struct fmt::formatter<std::optional<T>> : fmt::formatter<string_view> {
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template <typename FormatContext>
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auto format(const std::optional<T>& opt, FormatContext& ctx) const {
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if (opt) {
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return fmt::format_to(ctx.out(), "{}", *opt);
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} else {
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return fmt::format_to(ctx.out(), "{{}}");
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}
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}
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};
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#endif
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template <> struct fmt::formatter<std::strong_ordering> : fmt::formatter<string_view> {
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auto format(std::strong_ordering, fmt::format_context& ctx) const -> decltype(ctx.out());
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};
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template <> struct fmt::formatter<std::weak_ordering> : fmt::formatter<string_view> {
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auto format(std::weak_ordering, fmt::format_context& ctx) const -> decltype(ctx.out());
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};
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template <> struct fmt::formatter<std::partial_ordering> : fmt::formatter<string_view> {
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auto format(std::partial_ordering, fmt::format_context& ctx) const -> decltype(ctx.out());
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};
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