ripple::SeqProxy Class Reference

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

#include <SeqProxy.h>

Collaboration diagram for ripple::SeqProxy:

Public Types
enum	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 36 of file SeqProxy.h.

Member Enumeration Documentation

Type

enum ripple::SeqProxy::Type : std::uint8_t

Enumerator
seq
ticket

Definition at line 39 of file SeqProxy.h.

Constructor & Destructor Documentation

SeqProxy() [1/2]

constexpr ripple::SeqProxy::SeqProxy ( Type  t, std::uint32_t  v  )

explicitconstexpr

Definition at line 46 of file SeqProxy.h.

SeqProxy() [2/2]

ripple::SeqProxy::SeqProxy ( SeqProxy const &  other )

default

Member Function Documentation

operator=()

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

default

sequence()

static constexpr SeqProxy ripple::SeqProxy::sequence ( std::uint32_t  v )

staticconstexpr

Factory function to return a sequence-based SeqProxy.

Definition at line 57 of file SeqProxy.h.

value()

constexpr std::uint32_t ripple::SeqProxy::value ( ) const

constexpr

Definition at line 63 of file SeqProxy.h.

isSeq()

constexpr bool ripple::SeqProxy::isSeq ( ) const

constexpr

Definition at line 69 of file SeqProxy.h.

isTicket()

constexpr bool ripple::SeqProxy::isTicket ( ) const

constexpr

Definition at line 75 of file SeqProxy.h.

advanceBy()

SeqProxy & ripple::SeqProxy::advanceBy

(

std::uint32_t

amount

)

Definition at line 85 of file SeqProxy.h.

Friends And Related Symbol Documentation

operator==

constexpr bool operator== ( SeqProxy  lhs, SeqProxy  rhs  )

friend

Definition at line 102 of file SeqProxy.h.

operator!=

constexpr bool operator!= ( SeqProxy  lhs, SeqProxy  rhs  )

friend

Definition at line 110 of file SeqProxy.h.

operator<

constexpr bool operator< ( SeqProxy  lhs, SeqProxy  rhs  )

friend

Definition at line 115 of file SeqProxy.h.

operator>

constexpr bool operator> ( SeqProxy  lhs, SeqProxy  rhs  )

friend

Definition at line 124 of file SeqProxy.h.

operator>=

constexpr bool operator>= ( SeqProxy  lhs, SeqProxy  rhs  )

friend

Definition at line 130 of file SeqProxy.h.

operator<=

constexpr bool operator<= ( SeqProxy  lhs, SeqProxy  rhs  )

friend

Definition at line 135 of file SeqProxy.h.

operator<<

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

friend

Definition at line 141 of file SeqProxy.h.

Member Data Documentation

value_

std::uint32_t ripple::SeqProxy::value_

private

Definition at line 42 of file SeqProxy.h.

type_

Type ripple::SeqProxy::type_

private

Definition at line 43 of file SeqProxy.h.