Function write_bytes_atomic

src/CPfilepaths.cpp:132–163

}  // namespace

void write_bytes_atomic(const std::filesystem::path& target, const void* bytes, std::size_t size, bool restrict_perms) {
    const auto temp = make_temp_sibling(target);
    {
        std::ofstream out(temp, std::ios::binary | std::ios::trunc);
        if (!out) {
            throw std::runtime_error("write_bytes_atomic: cannot open temp " + temp.string());
        }
        if (size > 0) {
            out.write(reinterpret_cast<const char*>(bytes), static_cast<std::streamsize>(size));
        }
        out.flush();
        if (!out) {
            std::error_code ec_rm;
            std::filesystem::remove(temp, ec_rm);
            throw std::runtime_error("write_bytes_atomic: write failed for temp " + temp.string());
        }
    }
    if (restrict_perms) {
        std::error_code perm_ec;
        std::filesystem::permissions(temp, std::filesystem::perms::owner_read | std::filesystem::perms::owner_write,
                                     std::filesystem::perm_options::replace, perm_ec);
        // perm_ec ignored — owner-only is best-effort (no-op on Windows
        // where the POSIX permission model doesn't apply).
    }
    std::error_code rename_ec;
    std::filesystem::rename(temp, target, rename_ec);
    if (rename_ec) {
        std::error_code ec_rm;
        std::filesystem::remove(temp, ec_rm);
        throw std::runtime_error("write_bytes_atomic: rename to " + target.string() + " failed: " + rename_ec.message());
    }
}

// ---- make_dirs --------------------------------------------------------------