ZeroTierOne/ext/libpqxx-7.7.3/include/pqxx/transaction_focus.hxx
Adam Ierymenko b1faebae4a Re-add...
2022-06-23 13:24:33 -04:00

90 lines
2.7 KiB
C++

/** Transaction focus: types which monopolise a transaction's attention.
*
* Copyright (c) 2000-2022, Jeroen T. Vermeulen.
*
* See COPYING for copyright license. If you did not receive a file called
* COPYING with this source code, please notify the distributor of this
* mistake, or contact the author.
*/
#ifndef PQXX_H_TRANSACTION_FOCUS
#define PQXX_H_TRANSACTION_FOCUS
#if !defined(PQXX_HEADER_PRE)
# error "Include libpqxx headers as <pqxx/header>, not <pqxx/header.hxx>."
#endif
#include "pqxx/util.hxx"
namespace pqxx
{
/// Base class for things that monopolise a transaction's attention.
/** You probably won't need to use this class. But it can be useful to _know_
* that a given libpqxx class is derived from it.
*
* Pipelines, SQL statements, and data streams are examples of classes derived
* from `transaction_focus`. For any given transaction, only one object of
* such a class can be active at any given time.
*/
class PQXX_LIBEXPORT transaction_focus
{
public:
transaction_focus(
transaction_base &t, std::string_view cname, std::string_view oname) :
m_trans{t}, m_classname{cname}, m_name{oname}
{}
transaction_focus(
transaction_base &t, std::string_view cname, std::string &&oname) :
m_trans{t}, m_classname{cname}, m_name{std::move(oname)}
{}
transaction_focus(transaction_base &t, std::string_view cname) :
m_trans{t}, m_classname{cname}
{}
transaction_focus() = delete;
transaction_focus(transaction_focus const &) = delete;
transaction_focus &operator=(transaction_focus const &) = delete;
/// Class name, for human consumption.
[[nodiscard]] constexpr std::string_view classname() const noexcept
{
return m_classname;
}
/// Name for this object, if the caller passed one; empty string otherwise.
[[nodiscard]] std::string_view name() const &noexcept { return m_name; }
[[nodiscard]] std::string description() const
{
return pqxx::internal::describe_object(m_classname, m_name);
}
/// Can't move a transaction_focus.
/** Moving the transaction_focus would break the transaction's reference back
* to the object.
*/
transaction_focus(transaction_focus &&) = delete;
/// Can't move a transaction_focus.
/** Moving the transaction_focus would break the transaction's reference back
* to the object.
*/
transaction_focus &operator=(transaction_focus &&) = delete;
protected:
void register_me();
void unregister_me() noexcept;
void reg_pending_error(std::string const &) noexcept;
bool registered() const noexcept { return m_registered; }
transaction_base &m_trans;
private:
bool m_registered = false;
std::string_view m_classname;
std::string m_name;
};
} // namespace pqxx
#endif