An account can be made signable with only its regular key by
disabling the master key. Now an account can also be made
exclusively multisigned by both disabling the master key and
having no regular key.
In order to prevent an account from becoming unsignable the
network uses these rules:
o An account can always add or replace a regular key or a
SignerList as long as the fee and reserve can be met by the
account.
o The master key on an account can be disabled if either a
regular key or a SignerList (or both) is present on the account.
Either the regular key or the SignerList can be used to
re-enable the master key later if that is desired.
o The regular key on an account may only be removed if either the
master key is enabled or the account has a SignerList (or both).
o The SignerList on an account may only be removed if either the
master key is enabled or a regular key is present (or both).
As a consequence of this change, the tecMASTER_DISABLED error
code is renamed to tecNO_ALTERNATIVE_KEY. The error code number
(130 decimal) is unchanged.
The preflight() function performs static validity
analysis of transactions without requiring a ledger.
* Use tx in ApplyContext
* Remove unused journal
* Document apply()
* Add preflight(), which takes an OpenView, uses its rules.
* Change `TER preCheck` to `void preCompute` since it can no longer fail.
This tidies up the View interface and makes transaction
application a free function, with the removal of the
TransactionEngine class. A new class ApplyContext provides
all the state information needed to apply a Transactor. The
Transactor is refactored to perform all the processing
activities previously part of TransactionEngine.
The calculation of metadata from a MetaView is improved.
A new apply function performs all the steps for calculating
and inserting metadata into the tx map.
Transaction processing code path is passed a Config instead
of retrieving the global, and uses the Journal supplied in
the call to apply() consistently.
To support transaction processing and RPC operations, a
new POD type ViewInfo is added which consolidates static
information about open and closed ledgers, such as the ledger
sequence number or the closing times. Ledger and MetaView are
refactored to use this info.
The ViewInfo now contains the "open ledger" setting. The
tapOPEN_LEDGER ViewFlag is removed. The view property of
being an open ledger is obtained from the base or by using
the MetaView constructor which presents a closed ledger as
an open one.
View, MetaView:
* Fix missing includes
* Add apply free function
* Use Journal in TransactionEngine
* Use BasicView in TransactionEngine
* inline NetworkOPs::batchApply
* Add shallow_copy, open_ledger MetaView ctor tags
* Add ViewInfo with open flag, seq, close times
* Make parent_ a reference
* Tidy up ctor arguments and base_ name
* Remove tapOPEN_LEDGER
* add assert to MetaView::apply
* ViewInfo comment
* Throw, pass Journal in txInsert
* Add BasicView::txCount
TransactionEngine:
* Add apply
* Make TransactionEngine private
* Refactor MetaView::apply and apply()
* Rename to TxMeta
* Refactor treatment of metadata in MetaView, TransactionEngine
* Rename to ApplyContext
* Use ApplyContext& in Transactor
* Pass Config in ApplyContext
* Declare Transactor classes in headers
* Use view flags in Transactor
