SqlError.hpp

// SPDX-License-Identifier: Apache-2.0
 
#pragma once
 
#if defined(_WIN32) || defined(_WIN64)
    #include <Windows.h>
#endif
 
#include "Api.hpp"
 
#include <format>
#include <source_location>
#include <stdexcept>
#include <system_error>
 
#include <sql.h>
#include <sqlext.h>
#include <sqlspi.h>
#include <sqltypes.h>
 
/// @brief Represents an ODBC SQL error.
///
/// NOTE: This is a simple wrapper around the SQL return codes. It is not meant to be
/// comprehensive, but rather to provide a simple way to convert SQL return codes to
/// std::error_code.
///
/// The code below is DRAFT and may be subject to change.
struct SqlErrorInfo
{
    SQLINTEGER nativeErrorCode {};
    std::string sqlState = "     "; // 5 characters + null terminator
    std::string message;
 
    /// Constructs an ODBC error info object from the given ODBC connection handle.
    static SqlErrorInfo fromConnectionHandle(SQLHDBC hDbc)
    {
        return fromHandle(SQL_HANDLE_DBC, hDbc);
    }
 
    /// Constructs an ODBC error info object from the given ODBC statement handle.
    static SqlErrorInfo fromStatementHandle(SQLHSTMT hStmt)
    {
        return fromHandle(SQL_HANDLE_STMT, hStmt);
    }
 
    /// Asserts that the given result is a success code, otherwise throws an exception.
    static void RequireStatementSuccess(SQLRETURN result, SQLHSTMT hStmt, std::string_view message);
 
  private:
    static SqlErrorInfo fromHandle(SQLSMALLINT handleType, SQLHANDLE handle)
    {
        SqlErrorInfo info {};
        info.message = std::string(1024, '\0');
 
        SQLSMALLINT msgLen {};
        SQLGetDiagRecA(handleType,
                       handle,
                       1,
                       (SQLCHAR*) info.sqlState.data(),
                       &info.nativeErrorCode,
                       (SQLCHAR*) info.message.data(),
                       (SQLSMALLINT) info.message.capacity(),
                       &msgLen);
        info.message.resize(msgLen);
        return info;
    }
};
 
class SqlException: public std::runtime_error
{
  public:
    LIGHTWEIGHT_API explicit SqlException(SqlErrorInfo info,
                                          std::source_location location = std::source_location::current());
 
    [[nodiscard]] LIGHTWEIGHT_FORCE_INLINE SqlErrorInfo const& info() const noexcept
    {
        return _info;
    }
 
  private:
    SqlErrorInfo _info;
};
 
enum class SqlError : std::int16_t
{
    SUCCESS = SQL_SUCCESS,
    SUCCESS_WITH_INFO = SQL_SUCCESS_WITH_INFO,
    NODATA = SQL_NO_DATA,
    FAILURE = SQL_ERROR,
    INVALID_HANDLE = SQL_INVALID_HANDLE,
    STILL_EXECUTING = SQL_STILL_EXECUTING,
    NEED_DATA = SQL_NEED_DATA,
    PARAM_DATA_AVAILABLE = SQL_PARAM_DATA_AVAILABLE,
    NO_DATA_FOUND = SQL_NO_DATA_FOUND,
    UNSUPPORTED_TYPE = 1'000,
    INVALID_ARGUMENT = 1'001,
    TRANSACTION_ERROR = 1'002,
};
 
struct SqlErrorCategory: std::error_category
{
    static SqlErrorCategory const& get() noexcept
    {
        static SqlErrorCategory const category;
        return category;
    }
    [[nodiscard]] const char* name() const noexcept override
    {
        return "Lightweight";
    }
 
    [[nodiscard]] std::string message(int code) const override
    {
        using namespace std::string_literals;
        switch (static_cast<SqlError>(code))
        {
            case SqlError::SUCCESS:
                return "SQL_SUCCESS"s;
            case SqlError::SUCCESS_WITH_INFO:
                return "SQL_SUCCESS_WITH_INFO"s;
            case SqlError::NODATA:
                return "SQL_NO_DATA"s;
            case SqlError::FAILURE:
                return "SQL_ERROR"s;
            case SqlError::INVALID_HANDLE:
                return "SQL_INVALID_HANDLE"s;
            case SqlError::STILL_EXECUTING:
                return "SQL_STILL_EXECUTING"s;
            case SqlError::NEED_DATA:
                return "SQL_NEED_DATA"s;
            case SqlError::PARAM_DATA_AVAILABLE:
                return "SQL_PARAM_DATA_AVAILABLE"s;
            case SqlError::UNSUPPORTED_TYPE:
                return "SQL_UNSUPPORTED_TYPE"s;
            case SqlError::INVALID_ARGUMENT:
                return "SQL_INVALID_ARGUMENT"s;
            case SqlError::TRANSACTION_ERROR:
                return "SQL_TRANSACTION_ERROR"s;
        }
        return std::format("SQL error code {}", code);
    }
};
 
// Register our enum as an error code so we can constructor error_code from it
template <>
struct std::is_error_code_enum<SqlError>: public std::true_type
{
};
 
// Tells the compiler that MyErr pairs with MyCategory
inline std::error_code make_error_code(SqlError e)
{
    return { static_cast<int>(e), SqlErrorCategory::get() };
}
 
template <>
struct LIGHTWEIGHT_API std::formatter<SqlError>: formatter<std::string>
{
    auto format(SqlError value, format_context& ctx) const -> format_context::iterator
    {
        return formatter<std::string>::format(std::format("{}", SqlErrorCategory().message(static_cast<int>(value))),
                                              ctx);
    }
};
 
template <>
struct LIGHTWEIGHT_API std::formatter<SqlErrorInfo>: formatter<std::string>
{
    auto format(SqlErrorInfo const& info, format_context& ctx) const -> format_context::iterator
    {
        return formatter<std::string>::format(
            std::format("{} ({}) - {}", info.sqlState, info.nativeErrorCode, info.message), ctx);
    }
};