mirror of
https://github.com/XRPLF/rippled.git
synced 2026-06-03 00:36:48 +00:00
9294479a8a
# Conflicts: # include/xrpl/protocol/STParsedJSON.h # include/xrpl/shamap/SHAMapTreeNode.h # src/libxrpl/ledger/helpers/TokenHelpers.cpp # src/libxrpl/protocol/STIssue.cpp # src/libxrpl/protocol/STParsedJSON.cpp # src/libxrpl/shamap/SHAMapTreeNode.cpp # src/libxrpl/tx/invariants/PermissionedDEXInvariant.cpp # src/libxrpl/tx/transactors/nft/NFTokenAcceptOffer.cpp # src/libxrpl/tx/transactors/vault/VaultWithdraw.cpp # src/xrpld/rpc/detail/Role.cpp # src/xrpld/rpc/detail/TransactionSign.cpp # src/xrpld/rpc/handlers/account/AccountObjects.cpp
protocol
Classes and functions for handling data and values associated with the XRP Ledger protocol.
Serialized Objects
Objects transmitted over the network must be serialized into a canonical format. The prefix "ST" refers to classes that deal with the serialized format.
The term "Tx" or "tx" is an abbreviation for "Transaction", a commonly occurring object type.
Optional Fields
Our serialized fields have some "type magic" to make optional fields easier to read:
- The operation
x[sfFoo]means "return the value of 'Foo' if it exists, or the default value if it doesn't." - The operation
x[~sfFoo]means "return the value of 'Foo' if it exists, or nothing if it doesn't." This usage of the tilde/bitwise NOT operator is not standard outside of thexrpldcodebase.- As a consequence of this,
x[~sfFoo] = y[~sfFoo]assigns the value of Foo from y to x, including omitting Foo from x if it doesn't exist in y.
- As a consequence of this,
Typically, for things that are guaranteed to exist, you use
x[sfFoo] and avoid having to deal with a container that may
or may not hold a value. For things not guaranteed to exist,
you use x[~sfFoo] because you want such a container. It
avoids having to look something up twice, once just to see if
it exists and a second time to get/set its value.
(Real example)
The source of this "type magic" is in SField.h.