json_io.h

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#pragma once
 
#include <parcel/cell.h>
#include <parcel/error.h>
#include <parcel/json.h>
#include <parcel/registry.h>
 
#include <cstddef>
#include <span>
#include <string>
 
#if PARCEL_HAS_EXPECTED
#include <expected>
#endif
 
namespace parcel {
 
[[nodiscard]] inline cell_t cell_from_stream(std::istream& is, ParcelRegistry const& reg) {
    json_t j;
    is >> j;
    return reg.cell_from_json(j);
}
 
[[nodiscard]] inline cell_t cell_from_bytes(const std::span<const std::byte> bytes,
                                            ParcelRegistry const& reg) {
    // NOLINTBEGIN(cppcoreguidelines-pro-type-reinterpret-cast) — std::byte → const char* is the
    // canonical conversion at this boundary
    const auto j = json_t::parse(reinterpret_cast<const char*>(bytes.data()),
                                 reinterpret_cast<const char*>(bytes.data() + bytes.size()));
    // NOLINTEND(cppcoreguidelines-pro-type-reinterpret-cast)
    return reg.cell_from_json(j);
}
 
inline void cell_to_stream(std::ostream& os, cell_t const& c, const int indent = -1) {
    if (!c) {
        os << json_t().dump(indent);
        return;
    }
    os << c->to_json().dump(indent);
}
 
#if PARCEL_HAS_EXPECTED
[[nodiscard]] inline std::expected<cell_t, ParcelError>
try_cell_from_stream(std::istream& is, ParcelRegistry const& reg) {
    json_t j;
    try {
        is >> j;
    } catch (std::exception const& e) {
        return std::unexpected(ParcelError::make(ParcelError::Code::InvalidJson, e.what()));
    } catch (...) {
        return std::unexpected(
            ParcelError::make(ParcelError::Code::InvalidJson, "stream parse failed"));
    }
    return reg.try_cell_from_json(j);
}
 
[[nodiscard]] inline std::expected<cell_t, ParcelError>
try_cell_from_bytes(const std::span<const std::byte> bytes, ParcelRegistry const& reg) {
    json_t j;
    try {
        // NOLINTBEGIN(cppcoreguidelines-pro-type-reinterpret-cast) — std::byte → const char* is the
        // canonical conversion at this boundary
        j = json_t::parse(reinterpret_cast<const char*>(bytes.data()),
                          reinterpret_cast<const char*>(bytes.data() + bytes.size()));
        // NOLINTEND(cppcoreguidelines-pro-type-reinterpret-cast)
    } catch (std::exception const& e) {
        return std::unexpected(ParcelError::make(ParcelError::Code::InvalidJson, e.what()));
    } catch (...) {
        return std::unexpected(
            ParcelError::make(ParcelError::Code::InvalidJson, "bytes parse failed"));
    }
    return reg.try_cell_from_json(j);
}
#endif
 
}  // namespace parcel