Function SQLAllocHandle

cpp/src/arrow/flight/sql/odbc/odbc_api.cc:42–137

void LoadPropertiesFromDSN(const std::string& dsn, Connection::ConnPropertyMap& props);

SQLRETURN SQLAllocHandle(SQLSMALLINT type, SQLHANDLE parent, SQLHANDLE* result) {
  ARROW_LOG(DEBUG) << "SQLAllocHandle called with type: " << type
                   << ", parent: " << parent
                   << ", result: " << static_cast<const void*>(result);
  *result = nullptr;
  switch (type) {
    case SQL_HANDLE_ENV: {
      using ODBC::ODBCEnvironment;

      *result = SQL_NULL_HENV;

      try {
        static std::shared_ptr<FlightSqlDriver> odbc_driver =
            std::make_shared<FlightSqlDriver>();
        *result = reinterpret_cast<SQLHENV>(new ODBCEnvironment(odbc_driver));

        return SQL_SUCCESS;
      } catch (const std::bad_alloc&) {
        // allocating environment failed so cannot log diagnostic error here
        return SQL_ERROR;
      }
    }

    case SQL_HANDLE_DBC: {
      using ODBC::ODBCConnection;
      using ODBC::ODBCEnvironment;

      *result = SQL_NULL_HDBC;

      ODBCEnvironment* environment = reinterpret_cast<ODBCEnvironment*>(parent);

      return ODBCEnvironment::ExecuteWithDiagnostics(environment, SQL_ERROR, [=]() {
        std::shared_ptr<ODBCConnection> conn = environment->CreateConnection();

        if (conn) {
          // Inside `CreateConnection`, the shared_ptr `conn` is kept
          // in a `std::vector` of connections inside the environment handle.
          // As long as the parent environment handle is alive, the connection shared_ptr
          // will be kept alive unless the user frees the connection.
          *result = reinterpret_cast<SQLHDBC>(conn.get());

          return SQL_SUCCESS;
        }

        return SQL_ERROR;
      });
    }

    case SQL_HANDLE_STMT: {
      using ODBC::ODBCConnection;
      using ODBC::ODBCStatement;

      *result = SQL_NULL_HSTMT;

      ODBCConnection* connection = reinterpret_cast<ODBCConnection*>(parent);

      return ODBCConnection::ExecuteWithDiagnostics(connection, SQL_ERROR, [=]() {
        std::shared_ptr<ODBCStatement> statement = connection->CreateStatement();