xrpl::SeqProxy Class Reference

A type that represents either a sequence value or a ticket value. More...

#include <SeqProxy.h>

Collaboration diagram for xrpl::SeqProxy:

Public Types
enum class	Type : std::uint8_t { Seq = 0 , Ticket }

Public Member Functions
constexpr	SeqProxy (Type t, std::uint32_t v)
	SeqProxy (SeqProxy const &other)=default
SeqProxy &	operator= (SeqProxy const &other)=default
constexpr std::uint32_t	value () const
constexpr bool	isSeq () const
constexpr bool	isTicket () const
SeqProxy &	advanceBy (std::uint32_t amount)

Static Public Member Functions
static constexpr SeqProxy	sequence (std::uint32_t v)
	Factory function to return a sequence-based SeqProxy.

Private Attributes
std::uint32_t	value_
Type	type_

Friends
constexpr bool	operator== (SeqProxy lhs, SeqProxy rhs)
constexpr bool	operator!= (SeqProxy lhs, SeqProxy rhs)
constexpr bool	operator< (SeqProxy lhs, SeqProxy rhs)
constexpr bool	operator> (SeqProxy lhs, SeqProxy rhs)
constexpr bool	operator>= (SeqProxy lhs, SeqProxy rhs)
constexpr bool	operator<= (SeqProxy lhs, SeqProxy rhs)
std::ostream &	operator<< (std::ostream &os, SeqProxy seqProx)

Detailed Description

A type that represents either a sequence value or a ticket value.

We use the value() of a SeqProxy in places where a sequence was used before. An example of this is the sequence of an Offer stored in the ledger. We do the same thing with the in-ledger identifier of a Check, Payment Channel, and Escrow.

Why is this safe? If we use the SeqProxy::value(), how do we know that each ledger entry will be unique?

There are two components that make this safe:

1. A "TicketCreate" transaction carefully avoids creating a ticket that corresponds with an already used Sequence or Ticket value. The transactor does this by referring to the account root's sequence number. Creating the ticket advances the account root's sequence number so the same ticket (or sequence) value cannot be used again.

2. When a "TicketCreate" transaction creates a batch of tickets it advances the account root sequence to one past the largest created ticket.

   Therefore all tickets in a batch other than the first may never have the same value as a sequence on that same account. And since a ticket may only be used once there will never be any duplicates within this account.

Definition at line 35 of file SeqProxy.h.

Member Enumeration Documentation

Type

enum class xrpl::SeqProxy::Type : std::uint8_t

strong

Enumerator
Seq
Ticket

Definition at line 38 of file SeqProxy.h.

Constructor & Destructor Documentation

SeqProxy() [1/2]

xrpl::SeqProxy::SeqProxy ( Type t, std::uint32_t v )

explicitconstexpr

Definition at line 45 of file SeqProxy.h.

SeqProxy() [2/2]

xrpl::SeqProxy::SeqProxy ( SeqProxy const & other )

default

Member Function Documentation

operator=()

SeqProxy & xrpl::SeqProxy::operator= ( SeqProxy const & other )

default

sequence()

constexpr SeqProxy xrpl::SeqProxy::sequence ( std::uint32_t v )

staticconstexpr

Factory function to return a sequence-based SeqProxy.

Definition at line 56 of file SeqProxy.h.

value()

std::uint32_t xrpl::SeqProxy::value ( ) const

nodiscardconstexpr

Definition at line 62 of file SeqProxy.h.

isSeq()

bool xrpl::SeqProxy::isSeq ( ) const

nodiscardconstexpr

Definition at line 68 of file SeqProxy.h.

isTicket()

bool xrpl::SeqProxy::isTicket ( ) const

nodiscardconstexpr

Definition at line 74 of file SeqProxy.h.

advanceBy()

SeqProxy & xrpl::SeqProxy::advanceBy

(

std::uint32_t

amount

)

Definition at line 84 of file SeqProxy.h.

Friends And Related Symbol Documentation

operator==

bool operator== ( SeqProxy lhs, SeqProxy rhs )

friend

Definition at line 101 of file SeqProxy.h.

operator!=

bool operator!= ( SeqProxy lhs, SeqProxy rhs )

friend

Definition at line 109 of file SeqProxy.h.

operator<

bool operator< ( SeqProxy lhs, SeqProxy rhs )

friend

Definition at line 114 of file SeqProxy.h.

operator>

bool operator> ( SeqProxy lhs, SeqProxy rhs )

friend

Definition at line 123 of file SeqProxy.h.

operator>=

bool operator>= ( SeqProxy lhs, SeqProxy rhs )

friend

Definition at line 129 of file SeqProxy.h.

operator<=

bool operator<= ( SeqProxy lhs, SeqProxy rhs )

friend

Definition at line 134 of file SeqProxy.h.

operator<<

std::ostream & operator<< ( std::ostream & os, SeqProxy seqProx )

friend

Definition at line 140 of file SeqProxy.h.

Member Data Documentation

value_

std::uint32_t xrpl::SeqProxy::value_

private

Definition at line 41 of file SeqProxy.h.

type_

Type xrpl::SeqProxy::type_

private

Definition at line 42 of file SeqProxy.h.