command.hpp

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#ifndef GUARD_SQLITE_COMMAND_HPP_INCLUDED
#define GUARD_SQLITE_COMMAND_HPP_INCLUDED
 
#include <concepts>
#include <cstddef>
#include <cstdint>
#include <memory>
#include <span>
#include <string>
#include <string_view>
#include <type_traits>
#include <utility>
#include <vector>
#include <sqlite/connection.hpp>
#include <sqlite/detail/type_helpers.hpp>
 
struct sqlite3_stmt;

namespace sqlite {
inline namespace v2 {
    template <typename T> struct named_parameter {
        std::string name;
        T value;
    };
 
    template <typename T> named_parameter<std::decay_t<T>> named(std::string_view name, T &&value) {
        return {std::string(name), std::forward<T>(value)};
    }

    struct null_type {};

    extern null_type nil;

    struct command {
        struct statement_handle;

        command(connection &con, std::string const &sql);
        command(command const &)            = delete;
        command &operator=(command const &) = delete;

        virtual ~command();

        void clear();
        void reset_statement();

        bool step_once();

        bool operator()();

        template <typename... Args> bool operator()(Args &&...args) {
            if constexpr (sizeof...(Args) == 0) {
                return operator()();
            }
            reset_statement();
            ((void)(*this % std::forward<Args>(args)), ...);
            auto result = step();
            last_arg_idx = 0;
            return result;
        }

        void bind(int idx);

        void bind(int idx, int v);

        void bind(int idx, std::int64_t v);

        void bind(int idx, double v);

        template <typename Text>
            requires std::convertible_to<Text, std::string_view>
        void bind(int idx, Text &&text) {
            bind_text_impl(idx, std::string_view(std::forward<Text>(text)));
        }

        void bind(int idx, void const *buf, size_t buf_size);

        void bind(int idx, std::vector<unsigned char> const &v);
        void bind(int idx, std::span<const unsigned char> v);
        void bind(int idx, std::span<const std::byte> v);
 
        template <typename Value> void bind_value(int idx, Value &&value);
 
        int parameter_index(std::string_view name) const;
 
        template <typename Value> void bind(std::string_view name, Value &&value) {
            bind(parameter_index(name), std::forward<Value>(value));
        }
 
        template <typename Value>
            requires detail::needs_generic_binding_v<Value>
        void bind(int idx, Value &&value) {
            bind_value(idx, std::forward<Value>(value));
        }

        command &operator%(null_type const &p);

        command &operator%(int p);

        command &operator%(std::int64_t p);

        command &operator%(double p);

        template <typename Text>
            requires std::convertible_to<Text, std::string_view>
        command &operator%(Text &&p) {
            bind(++last_arg_idx, std::string_view(std::forward<Text>(p)));
            return *this;
        }

        command &operator%(std::vector<unsigned char> const &p);
        command &operator%(std::span<const unsigned char> p);
        command &operator%(std::span<const std::byte> p);
 
        template <typename T> command &operator%(named_parameter<T> param) {
            bind(param.name, std::move(param.value));
            return *this;
        }
 
        template <typename Value>
            requires detail::needs_generic_binding_v<detail::decay_t<Value>>
        command &operator%(Value &&value) {
            bind_value(++last_arg_idx, std::forward<Value>(value));
            return *this;
        }
 
    protected:
        void access_check() const;
        bool step();
        struct sqlite3 *get_handle();
        std::string const &sql_text() const noexcept;
        std::shared_ptr<statement_handle> shared_statement() const;
 
    private:
        void prepare();
        void finalize();
        void bind_text_impl(int idx, std::string_view text);
 
    private:
        connection &m_con;
        std::string m_sql;
 
    protected:
        sqlite3_stmt *stmt;
 
    private:
        std::shared_ptr<statement_handle> stmt_owner_;
        int last_arg_idx;
    };
 
    template <typename Value> void command::bind_value(int idx, Value &&value) {
        using decayed = detail::decay_t<Value>;
        if constexpr (detail::is_optional_v<decayed>) {
            if (!value) {
                bind(idx);
            } else {
                bind_value(idx, *value);
            }
        } else if constexpr (detail::is_duration_v<decayed>) {
            auto micros = std::chrono::duration_cast<std::chrono::microseconds>(value).count();
            bind(idx, static_cast<std::int64_t>(micros));
        } else if constexpr (detail::is_time_point_v<decayed>) {
            auto micros =
                std::chrono::duration_cast<std::chrono::microseconds>(value.time_since_epoch())
                    .count();
            bind(idx, static_cast<std::int64_t>(micros));
        } else if constexpr (std::is_enum_v<decayed>) {
            bind(idx, static_cast<std::int64_t>(value));
        } else if constexpr (std::is_integral_v<decayed>) {
            bind(idx, static_cast<std::int64_t>(value));
        } else if constexpr (std::is_floating_point_v<decayed>) {
            bind(idx, static_cast<double>(value));
        } else if constexpr (detail::is_string_like_v<decayed>) {
            bind(idx, std::string_view(std::forward<Value>(value)));
        } else if constexpr (detail::is_byte_vector_v<decayed>) {
            bind(idx, value);
        } else if constexpr (detail::is_unsigned_char_span_v<decayed>) {
            bind(idx, value);
        } else if constexpr (detail::is_byte_span_v<decayed>) {
            bind(idx, value);
        } else {
            static_assert(detail::always_false_v<decayed>,
                          "Unsupported type for sqlite::command::bind_value");
        }
    }
} // namespace v2
} // namespace sqlite
 
#endif // GUARD_SQLITE_COMMAND_HPP_INCLUDED