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42 lines
1.1 KiB
C++
42 lines
1.1 KiB
C++
/*
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* Copyright (C) 2025-present ScyllaDB
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*/
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/*
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* SPDX-License-Identifier: LicenseRef-ScyllaDB-Source-Available-1.1
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*/
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#pragma once
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#include <fmt/format.h>
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#include <functional>
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/// Type-erased formatter.
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/// Allows passing formattable objects without exposing their types.
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class abstract_formatter {
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std::function<void(fmt::format_context&)> _formatter;
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public:
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abstract_formatter() = default;
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template<typename Func>
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requires std::is_invocable_v<Func, fmt::format_context&>
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explicit abstract_formatter(Func&& f) : _formatter(std::forward<Func>(f)) {}
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fmt::format_context::iterator format_to(fmt::format_context& ctx) const {
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if (_formatter) {
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_formatter(ctx);
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}
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return ctx.out();
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}
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explicit operator bool() const noexcept { return bool(_formatter); }
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};
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template <> struct fmt::formatter<abstract_formatter> {
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constexpr auto parse(format_parse_context& ctx) { return ctx.begin(); }
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auto format(const abstract_formatter& formatter, fmt::format_context& ctx) const {
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return formatter.format_to(ctx);
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}
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};
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