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refactor: Split LoanInvariant into LoanBrokerInvariant and LoanInvariant (#6674)
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+250
-229
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5 files changed

+250
-229
lines changed

‎include/xrpl/tx/invariants/InvariantCheck.h‎

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#include <xrpl/protocol/TER.h>
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#include <xrpl/tx/invariants/AMMInvariant.h>
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#include <xrpl/tx/invariants/FreezeInvariant.h>
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#include <xrpl/tx/invariants/LoanBrokerInvariant.h>
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#include <xrpl/tx/invariants/LoanInvariant.h>
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#include <xrpl/tx/invariants/MPTInvariant.h>
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#include <xrpl/tx/invariants/NFTInvariant.h>

‎include/xrpl/tx/invariants/LoanBrokerInvariant.h‎

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#pragma once
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#include <xrpl/basics/base_uint.h>
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#include <xrpl/beast/utility/Journal.h>
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#include <xrpl/ledger/ReadView.h>
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#include <xrpl/protocol/STTx.h>
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#include <xrpl/protocol/TER.h>
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#include <map>
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#include <vector>
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namespace xrpl {
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/**
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* @brief Invariants: Loan brokers are internally consistent
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*
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* 1. If `LoanBroker.OwnerCount = 0` the `DirectoryNode` will have at most one
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* node (the root), which will only hold entries for `RippleState` or
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* `MPToken` objects.
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*
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*/
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class ValidLoanBroker
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{
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// Not all of these elements will necessarily be populated. Remaining items
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// will be looked up as needed.
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struct BrokerInfo
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{
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SLE::const_pointer brokerBefore = nullptr;
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// After is used for most of the checks, except
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// those that check changed values.
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SLE::const_pointer brokerAfter = nullptr;
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};
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// Collect all the LoanBrokers found directly or indirectly through
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// pseudo-accounts. Key is the brokerID / index. It will be used to find the
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// LoanBroker object if brokerBefore and brokerAfter are nullptr
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std::map<uint256, BrokerInfo> brokers_;
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// Collect all the modified trust lines. Their high and low accounts will be
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// loaded to look for LoanBroker pseudo-accounts.
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std::vector<SLE::const_pointer> lines_;
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// Collect all the modified MPTokens. Their accounts will be loaded to look
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// for LoanBroker pseudo-accounts.
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std::vector<SLE::const_pointer> mpts_;
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static bool
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goodZeroDirectory(ReadView const& view, SLE::const_ref dir, beast::Journal const& j);
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public:
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void
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visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
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bool
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finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&);
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};
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} // namespace xrpl

‎include/xrpl/tx/invariants/LoanInvariant.h‎

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#pragma once
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3-
#include <xrpl/basics/base_uint.h>
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#include <xrpl/beast/utility/Journal.h>
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#include <xrpl/ledger/ReadView.h>
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#include <xrpl/protocol/STTx.h>
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#include <xrpl/protocol/TER.h>
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#include <map>
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#include <vector>
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namespace xrpl {
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/**
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* @brief Invariants: Loan brokers are internally consistent
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*
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* 1. If `LoanBroker.OwnerCount = 0` the `DirectoryNode` will have at most one
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* node (the root), which will only hold entries for `RippleState` or
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* `MPToken` objects.
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*
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*/
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class ValidLoanBroker
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{
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// Not all of these elements will necessarily be populated. Remaining items
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// will be looked up as needed.
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struct BrokerInfo
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{
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SLE::const_pointer brokerBefore = nullptr;
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// After is used for most of the checks, except
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// those that check changed values.
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SLE::const_pointer brokerAfter = nullptr;
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};
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// Collect all the LoanBrokers found directly or indirectly through
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// pseudo-accounts. Key is the brokerID / index. It will be used to find the
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// LoanBroker object if brokerBefore and brokerAfter are nullptr
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std::map<uint256, BrokerInfo> brokers_;
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// Collect all the modified trust lines. Their high and low accounts will be
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// loaded to look for LoanBroker pseudo-accounts.
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std::vector<SLE::const_pointer> lines_;
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// Collect all the modified MPTokens. Their accounts will be loaded to look
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// for LoanBroker pseudo-accounts.
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std::vector<SLE::const_pointer> mpts_;
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static bool
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goodZeroDirectory(ReadView const& view, SLE::const_ref dir, beast::Journal const& j);
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public:
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void
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visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
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bool
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finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&);
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};
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/**
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* @brief Invariants: Loans are internally consistent
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*

‎src/libxrpl/tx/invariants/LoanBrokerInvariant.cpp‎

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#include <xrpl/tx/invariants/LoanBrokerInvariant.h>
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//
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#include <xrpl/basics/Log.h>
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#include <xrpl/beast/utility/instrumentation.h>
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#include <xrpl/ledger/View.h>
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#include <xrpl/ledger/helpers/RippleStateHelpers.h>
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#include <xrpl/protocol/Indexes.h>
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#include <xrpl/protocol/LedgerFormats.h>
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#include <xrpl/protocol/STNumber.h>
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#include <xrpl/protocol/TxFormats.h>
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namespace xrpl {
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void
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ValidLoanBroker::visitEntry(
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bool isDelete,
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std::shared_ptr<SLE const> const& before,
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std::shared_ptr<SLE const> const& after)
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{
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if (after)
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{
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if (after->getType() == ltLOAN_BROKER)
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{
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auto& broker = brokers_[after->key()];
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broker.brokerBefore = before;
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broker.brokerAfter = after;
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}
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else if (after->getType() == ltACCOUNT_ROOT && after->isFieldPresent(sfLoanBrokerID))
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{
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auto const& loanBrokerID = after->at(sfLoanBrokerID);
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// create an entry if one doesn't already exist
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brokers_.emplace(loanBrokerID, BrokerInfo{});
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}
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else if (after->getType() == ltRIPPLE_STATE)
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{
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lines_.emplace_back(after);
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}
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else if (after->getType() == ltMPTOKEN)
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{
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mpts_.emplace_back(after);
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}
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}
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}
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bool
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ValidLoanBroker::goodZeroDirectory(
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ReadView const& view,
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SLE::const_ref dir,
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beast::Journal const& j)
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{
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auto const next = dir->at(~sfIndexNext);
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auto const prev = dir->at(~sfIndexPrevious);
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if ((prev && (*prev != 0u)) || (next && (*next != 0u)))
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{
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JLOG(j.fatal()) << "Invariant failed: Loan Broker with zero "
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"OwnerCount has multiple directory pages";
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return false;
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}
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auto indexes = dir->getFieldV256(sfIndexes);
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if (indexes.size() > 1)
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{
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JLOG(j.fatal()) << "Invariant failed: Loan Broker with zero "
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"OwnerCount has multiple indexes in the Directory root";
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return false;
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}
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if (indexes.size() == 1)
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{
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auto const index = indexes.value().front();
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auto const sle = view.read(keylet::unchecked(index));
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if (!sle)
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{
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JLOG(j.fatal()) << "Invariant failed: Loan Broker directory corrupt";
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return false;
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}
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if (sle->getType() != ltRIPPLE_STATE && sle->getType() != ltMPTOKEN)
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{
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JLOG(j.fatal()) << "Invariant failed: Loan Broker with zero "
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"OwnerCount has an unexpected entry in the directory";
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return false;
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}
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}
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return true;
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}
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bool
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ValidLoanBroker::finalize(
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STTx const& tx,
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TER const,
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XRPAmount const,
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ReadView const& view,
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beast::Journal const& j)
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{
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// Loan Brokers will not exist on ledger if the Lending Protocol amendment
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// is not enabled, so there's no need to check it.
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for (auto const& line : lines_)
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{
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for (auto const& field : {&sfLowLimit, &sfHighLimit})
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{
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auto const account = view.read(keylet::account(line->at(*field).getIssuer()));
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// This Invariant doesn't know about the rules for Trust Lines, so
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// if the account is missing, don't treat it as an error. This
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// loop is only concerned with finding Broker pseudo-accounts
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if (account && account->isFieldPresent(sfLoanBrokerID))
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{
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auto const& loanBrokerID = account->at(sfLoanBrokerID);
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// create an entry if one doesn't already exist
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brokers_.emplace(loanBrokerID, BrokerInfo{});
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}
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}
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}
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for (auto const& mpt : mpts_)
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{
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auto const account = view.read(keylet::account(mpt->at(sfAccount)));
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// This Invariant doesn't know about the rules for MPTokens, so
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// if the account is missing, don't treat is as an error. This
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// loop is only concerned with finding Broker pseudo-accounts
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if (account && account->isFieldPresent(sfLoanBrokerID))
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{
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auto const& loanBrokerID = account->at(sfLoanBrokerID);
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// create an entry if one doesn't already exist
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brokers_.emplace(loanBrokerID, BrokerInfo{});
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}
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}
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for (auto const& [brokerID, broker] : brokers_)
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{
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auto const& after =
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broker.brokerAfter ? broker.brokerAfter : view.read(keylet::loanbroker(brokerID));
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if (!after)
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{
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JLOG(j.fatal()) << "Invariant failed: Loan Broker missing";
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return false;
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}
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auto const& before = broker.brokerBefore;
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// https://github.com/Tapanito/XRPL-Standards/blob/xls-66-lending-protocol/XLS-0066d-lending-protocol/README.md#3123-invariants
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// If `LoanBroker.OwnerCount = 0` the `DirectoryNode` will have at most
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// one node (the root), which will only hold entries for `RippleState`
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// or `MPToken` objects.
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if (after->at(sfOwnerCount) == 0)
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{
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auto const dir = view.read(keylet::ownerDir(after->at(sfAccount)));
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if (dir)
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{
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if (!goodZeroDirectory(view, dir, j))
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{
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return false;
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}
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}
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}
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if (before && before->at(sfLoanSequence) > after->at(sfLoanSequence))
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{
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JLOG(j.fatal()) << "Invariant failed: Loan Broker sequence number "
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"decreased";
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return false;
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}
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if (after->at(sfDebtTotal) < 0)
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{
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JLOG(j.fatal()) << "Invariant failed: Loan Broker debt total is negative";
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return false;
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}
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if (after->at(sfCoverAvailable) < 0)
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{
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JLOG(j.fatal()) << "Invariant failed: Loan Broker cover available is negative";
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return false;
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}
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auto const vault = view.read(keylet::vault(after->at(sfVaultID)));
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if (!vault)
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{
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JLOG(j.fatal()) << "Invariant failed: Loan Broker vault ID is invalid";
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return false;
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}
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auto const& vaultAsset = vault->at(sfAsset);
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if (after->at(sfCoverAvailable) < accountHolds(
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view,
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after->at(sfAccount),
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vaultAsset,
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FreezeHandling::fhIGNORE_FREEZE,
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AuthHandling::ahIGNORE_AUTH,
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j))
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{
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JLOG(j.fatal()) << "Invariant failed: Loan Broker cover available "
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"is less than pseudo-account asset balance";
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return false;
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}
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}
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return true;
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}
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} // namespace xrpl

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