serialize.hpp

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#pragma once
 
/// @file userver/formats/json/serialize.hpp
/// @brief Parsers and serializers to/from string and stream
 
#include <iosfwd>
#include <string_view>
 
#include <fmt/format.h>
 
#include <userver/formats/json/value.hpp>
#include <userver/utils/fast_pimpl.hpp>
#include <userver/utils/fmt_compat.hpp>
 
USERVER_NAMESPACE_BEGIN
 
namespace logging {
 
class LogHelper;
 
}  // namespace logging
 
namespace formats::json {
 
constexpr inline std::size_t kDepthParseLimit = 128;
 
/// Parse JSON from string
formats::json::Value FromString(std::string_view doc);
 
/// Parse JSON from stream
formats::json::Value FromStream(std::istream& is);
 
/// Serialize JSON to stream
void Serialize(const formats::json::Value& doc, std::ostream& os);
 
/// Serialize JSON to string
std::string ToString(const formats::json::Value& doc);
 
/// Stably serialize JSON to string. In result there is no whitespace, keys
/// are sorted and character escaping is stabilized
std::string ToStableString(const formats::json::Value& doc);
 
/// @overload
std::string ToStableString(formats::json::Value&& doc);
 
/// @see formats::json::ToPrettyString
struct PrettyFormat final {
    char indent_char{' '};
    std::size_t indent_char_count{2};
};
 
/// Serialize JSON to a string, using `\n` and indents for objects and arrays.
std::string ToPrettyString(const formats::json::Value& doc, PrettyFormat format = {});
 
/// Log JSON
logging::LogHelper& operator<<(logging::LogHelper&, const formats::json::Value&);
 
/// @brief Blocking operations that should not be used on main task processor after startup
namespace blocking {
/// Read JSON from file
formats::json::Value FromFile(const std::string& path);
}  // namespace blocking
 
namespace impl {
 
class StringBuffer final {
public:
    explicit StringBuffer(const formats::json::Value& value);
    ~StringBuffer();
 
    std::string_view GetStringView() const;
 
private:
    struct Impl;
    static constexpr std::size_t kSize = 48;
    static constexpr std::size_t kAlignment = 8;
    utils::FastPimpl<Impl, kSize, kAlignment> pimpl_;
};
 
}  // namespace impl
 
}  // namespace formats::json
 
USERVER_NAMESPACE_END
 
template <>
struct fmt::formatter<USERVER_NAMESPACE::formats::json::Value> : fmt::formatter<std::string_view> {
    constexpr static auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) { return ctx.begin(); }
 
    template <typename FormatContext>
    auto format(const USERVER_NAMESPACE::formats::json::Value& value, FormatContext& ctx)
        USERVER_FMT_CONST -> decltype(ctx.out()) {
        const USERVER_NAMESPACE::formats::json::impl::StringBuffer buffer(value);
        return fmt::format_to(ctx.out(), "{}", buffer.GetStringView());
    }
};