// Append a node, then create and insert before it any implied nodes. Order
// book nodes may go back to back.
//
// For each non-matching pair of IssuedCurrency, there's an order book.
//
// <-- resultCode: tesSUCCESS, temBAD_PATH, terNO_ACCOUNT, terNO_AUTH,
// terNO_LINE, tecPATH_DRY
TER PathState::pushNode (
const int iType,
AccountID const& account, // If not specified, means an order book.
Currency const& currency, // If not specified, default to previous.
AccountID const& issuer) // If not specified, default to previous.
{
path::Node node;
const bool pathIsEmpty = nodes_.empty ();
// TODO(tom): if pathIsEmpty, we probably don't need to do ANYTHING below.
// Indeed, we might just not even call pushNode in the first place!
auto const& backNode = pathIsEmpty ? path::Node () : nodes_.back ();
// true, iff node is a ripple account. false, iff node is an offer node.
const bool hasAccount = (iType & STPathElement::typeAccount);
// Is currency specified for the output of the current node?
const bool hasCurrency = (iType & STPathElement::typeCurrency);
// Issuer is specified for the output of the current node.
const bool hasIssuer = (iType & STPathElement::typeIssuer);
TER resultCode = tesSUCCESS;
JLOG (j_.trace)
<< "pushNode> " << iType << ": "
<< (hasAccount ? to_string(account) : std::string("-")) << " "
<< (hasCurrency ? to_string(currency) : std::string("-")) << "/"
<< (hasIssuer ? to_string(issuer) : std::string("-")) << "/";
node.uFlags = iType;
node.issue_.currency = hasCurrency ?
currency : backNode.issue_.currency;
// TODO(tom): we can probably just return immediately whenever we hit an
// error in these next pages.
if (iType & ~STPathElement::typeAll)
{
// Of course, this could never happen.
JLOG (j_.debug) << "pushNode: bad bits.";
resultCode = temBAD_PATH;
}
else if (hasIssuer && isXRP (node.issue_))
{
JLOG (j_.debug) << "pushNode: issuer specified for XRP.";
resultCode = temBAD_PATH;
}
else if (hasIssuer && !issuer)
{
JLOG (j_.debug) << "pushNode: specified bad issuer.";
resultCode = temBAD_PATH;
}
else if (!hasAccount && !hasCurrency && !hasIssuer)
{
// You can't default everything to the previous node as you would make
// no progress.
JLOG (j_.debug)
<< "pushNode: offer must specify at least currency or issuer.";
resultCode = temBAD_PATH;
}
else if (hasAccount)
{
// Account link
node.account_ = account;
node.issue_.account = hasIssuer ? issuer :
(isXRP (node.issue_) ? xrpAccount() : account);
// Zero value - for accounts.
node.saRevRedeem = STAmount ({node.issue_.currency, account});
node.saRevIssue = node.saRevRedeem;
// For order books only - zero currency with the issuer ID.
node.saRevDeliver = STAmount (node.issue_);
node.saFwdDeliver = node.saRevDeliver;
if (pathIsEmpty)
{
// The first node is always correct as is.
}
else if (!account)
{
JLOG (j_.debug)
<< "pushNode: specified bad account.";
resultCode = temBAD_PATH;
}
else
{
// Add required intermediate nodes to deliver to current account.
JLOG (j_.trace)
<< "pushNode: imply for account.";
resultCode = pushImpliedNodes (
node.account_,
node.issue_.currency,
isXRP(node.issue_.currency) ? xrpAccount() : account);
// Note: backNode may no longer be the immediately previous node.
}
if (resultCode == tesSUCCESS && !nodes_.empty ())
{
auto const& backNode = nodes_.back ();
if (backNode.isAccount())
{
auto sleRippleState = view().peek(
keylet::line(backNode.account_, node.account_, backNode.issue_.currency));
// A "RippleState" means a balance betweeen two accounts for a
// specific currency.
if (!sleRippleState)
{
JLOG (j_.trace)
<< "pushNode: No credit line between "
<< backNode.account_ << " and " << node.account_
<< " for " << node.issue_.currency << "." ;
JLOG (j_.trace) << getJson ();
resultCode = terNO_LINE;
}
else
{
JLOG (j_.trace)
<< "pushNode: Credit line found between "
<< backNode.account_ << " and " << node.account_
<< " for " << node.issue_.currency << "." ;
auto sleBck = view().peek (
keylet::account(backNode.account_));
// Is the source account the highest numbered account ID?
bool bHigh = backNode.account_ > node.account_;
if (!sleBck)
{
JLOG (j_.warning)
<< "pushNode: delay: can't receive IOUs from "
<< "non-existent issuer: " << backNode.account_;
resultCode = terNO_ACCOUNT;
}
else if ((sleBck->getFieldU32 (sfFlags) & lsfRequireAuth) &&
!(sleRippleState->getFieldU32 (sfFlags) &
(bHigh ? lsfHighAuth : lsfLowAuth)) &&
sleRippleState->getFieldAmount(sfBalance) == zero)
{
JLOG (j_.warning)
<< "pushNode: delay: can't receive IOUs from "
<< "issuer without auth.";
resultCode = terNO_AUTH;
}
if (resultCode == tesSUCCESS)
{
STAmount saOwed = creditBalance (view(),
node.account_, backNode.account_,
node.issue_.currency);
STAmount saLimit;
if (saOwed <= zero)
{
saLimit = creditLimit (view(),
node.account_,
backNode.account_,
node.issue_.currency);
if (-saOwed >= saLimit)
{
JLOG (j_.debug) <<
"pushNode: dry:" <<
" saOwed=" << saOwed <<
" saLimit=" << saLimit;
resultCode = tecPATH_DRY;
}
}
}
}
}
}
if (resultCode == tesSUCCESS)
nodes_.push_back (node);
}
else
{
// Offer link.
//
// Offers bridge a change in currency and issuer, or just a change in
// issuer.
if (hasIssuer)
node.issue_.account = issuer;
else if (isXRP (node.issue_.currency))
node.issue_.account = xrpAccount();
else if (isXRP (backNode.issue_.account))
node.issue_.account = backNode.account_;
else
node.issue_.account = backNode.issue_.account;
node.saRateMax = STAmount::saZero;
node.saRevDeliver = STAmount (node.issue_);
node.saFwdDeliver = node.saRevDeliver;
if (!isConsistent (node.issue_))
{
JLOG (j_.debug)
<< "pushNode: currency is inconsistent with issuer.";
resultCode = temBAD_PATH;
}
else if (backNode.issue_ == node.issue_)
{
JLOG (j_.debug) <<
"pushNode: bad path: offer to same currency and issuer";
resultCode = temBAD_PATH;
}
else {
JLOG (j_.trace) << "pushNode: imply for offer.";
// Insert intermediary issuer account if needed.
resultCode = pushImpliedNodes (
xrpAccount(), // Rippling, but offers don't have an account.
backNode.issue_.currency,
backNode.issue_.account);
}
if (resultCode == tesSUCCESS)
nodes_.push_back (node);
}
JLOG (j_.trace) << "pushNode< : " << transToken (resultCode);
return resultCode;
}
TER PathCursor::reverseLiquidityForAccount () const
{
TER terResult = tesSUCCESS;
auto const lastNodeIndex = nodeSize () - 1;
auto const isFinalNode = (nodeIndex_ == lastNodeIndex);
// 0 quality means none has yet been determined.
std::uint64_t uRateMax = 0;
// Current is allowed to redeem to next.
const bool previousNodeIsAccount = !nodeIndex_ ||
previousNode().isAccount();
const bool nextNodeIsAccount = isFinalNode || nextNode().isAccount();
AccountID const& previousAccountID = previousNodeIsAccount
? previousNode().account_ : node().account_;
AccountID const& nextAccountID = nextNodeIsAccount ? nextNode().account_
: node().account_; // Offers are always issue.
// This is the quality from from the previous node to this one.
auto const qualityIn
= (nodeIndex_ != 0)
? quality_in (view(),
node().account_,
previousAccountID,
node().issue_.currency)
: parityRate;
// And this is the quality from the next one to this one.
auto const qualityOut
= (nodeIndex_ != lastNodeIndex)
? quality_out (view(),
node().account_,
nextAccountID,
node().issue_.currency)
: parityRate;
// For previousNodeIsAccount:
// Previous account is already owed.
const STAmount saPrvOwed = (previousNodeIsAccount && nodeIndex_ != 0)
? creditBalance (view(),
node().account_,
previousAccountID,
node().issue_.currency)
: STAmount (node().issue_);
// The limit amount that the previous account may owe.
const STAmount saPrvLimit = (previousNodeIsAccount && nodeIndex_ != 0)
? creditLimit (view(),
node().account_,
previousAccountID,
node().issue_.currency)
: STAmount (node().issue_);
// Next account is owed.
const STAmount saNxtOwed = (nextNodeIsAccount && nodeIndex_ != lastNodeIndex)
? creditBalance (view(),
node().account_,
nextAccountID,
node().issue_.currency)
: STAmount (node().issue_);
JLOG (j_.trace())
<< "reverseLiquidityForAccount>"
<< " nodeIndex_=" << nodeIndex_ << "/" << lastNodeIndex
<< " previousAccountID=" << previousAccountID
<< " node.account_=" << node().account_
<< " nextAccountID=" << nextAccountID
<< " currency=" << node().issue_.currency
<< " qualityIn=" << qualityIn
<< " qualityOut=" << qualityOut
<< " saPrvOwed=" << saPrvOwed
<< " saPrvLimit=" << saPrvLimit;
// Requests are computed to be the maximum flow possible.
// Previous can redeem the owed IOUs it holds.
const STAmount saPrvRedeemReq = (saPrvOwed > beast::zero)
? saPrvOwed
: STAmount (saPrvOwed.issue ());
// Previous can issue up to limit minus whatever portion of limit already
// used (not including redeemable amount) - another "maximum flow".
const STAmount saPrvIssueReq = (saPrvOwed < beast::zero)
? saPrvLimit + saPrvOwed : saPrvLimit;
// Precompute these values in case we have an order book.
auto deliverCurrency = previousNode().saRevDeliver.getCurrency ();
const STAmount saPrvDeliverReq (
{deliverCurrency, previousNode().saRevDeliver.getIssuer ()}, -1);
// -1 means unlimited delivery.
// Set to zero, because we're trying to hit the previous node.
auto saCurRedeemAct = node().saRevRedeem.zeroed();
// Track the amount we actually redeem.
auto saCurIssueAct = node().saRevIssue.zeroed();
// For !nextNodeIsAccount
auto saCurDeliverAct = node().saRevDeliver.zeroed();
JLOG (j_.trace())
<< "reverseLiquidityForAccount:"
<< " saPrvRedeemReq:" << saPrvRedeemReq
<< " saPrvIssueReq:" << saPrvIssueReq
<< " previousNode.saRevDeliver:" << previousNode().saRevDeliver
<< " saPrvDeliverReq:" << saPrvDeliverReq
<< " node.saRevRedeem:" << node().saRevRedeem
<< " node.saRevIssue:" << node().saRevIssue
<< " saNxtOwed:" << saNxtOwed;
// VFALCO-FIXME this generates errors
//JLOG (j_.trace()) << pathState_.getJson ();
// Current redeem req can't be more than IOUs on hand.
assert (!node().saRevRedeem || -saNxtOwed >= node().saRevRedeem);
assert (!node().saRevIssue // If not issuing, fine.
|| saNxtOwed >= beast::zero
// saNxtOwed >= 0: Sender not holding next IOUs, saNxtOwed < 0:
// Sender holding next IOUs.
|| -saNxtOwed == node().saRevRedeem);
// If issue req, then redeem req must consume all owed.
if (nodeIndex_ == 0)
{
// ^ --> ACCOUNT --> account|offer
// Nothing to do, there is no previous to adjust.
//
// TODO(tom): we could have skipped all that setup and just left
// or even just never call this whole routine on nodeIndex_ = 0!
}
// The next four cases correspond to the table at the bottom of this Wiki
// page section: https://ripple.com/wiki/Transit_Fees#Implementation
else if (previousNodeIsAccount && nextNodeIsAccount)
{
if (isFinalNode)
{
// account --> ACCOUNT --> $
// Overall deliverable.
const STAmount saCurWantedReq = std::min (
pathState_.outReq() - pathState_.outAct(),
saPrvLimit + saPrvOwed);
auto saCurWantedAct = saCurWantedReq.zeroed ();
JLOG (j_.trace())
<< "reverseLiquidityForAccount: account --> "
<< "ACCOUNT --> $ :"
<< " saCurWantedReq=" << saCurWantedReq;
// Calculate redeem
if (saPrvRedeemReq) // Previous has IOUs to redeem.
{
// Redeem your own IOUs at 1:1
saCurWantedAct = std::min (saPrvRedeemReq, saCurWantedReq);
previousNode().saRevRedeem = saCurWantedAct;
uRateMax = STAmount::uRateOne;
JLOG (j_.trace())
<< "reverseLiquidityForAccount: Redeem at 1:1"
<< " saPrvRedeemReq=" << saPrvRedeemReq
<< " (available) previousNode.saRevRedeem="
<< previousNode().saRevRedeem
<< " uRateMax="
<< amountFromQuality (uRateMax).getText ();
}
else
{
previousNode().saRevRedeem.clear (saPrvRedeemReq);
}
// Calculate issuing.
previousNode().saRevIssue.clear (saPrvIssueReq);
if (saCurWantedReq != saCurWantedAct // Need more.
&& saPrvIssueReq) // Will accept IOUs from previous.
{
// Rate: quality in : 1.0
// If we previously redeemed and this has a poorer rate, this
// won't be included the current increment.
rippleLiquidity (
rippleCalc_,
qualityIn,
parityRate,
saPrvIssueReq,
saCurWantedReq,
previousNode().saRevIssue,
saCurWantedAct,
uRateMax);
JLOG (j_.trace())
<< "reverseLiquidityForAccount: Issuing: Rate: "
<< "quality in : 1.0"
<< " previousNode.saRevIssue:" << previousNode().saRevIssue
<< " saCurWantedAct:" << saCurWantedAct;
}
if (!saCurWantedAct)
{
// Must have processed something.
terResult = tecPATH_DRY;
}
}
else
{
// Not final node.
// account --> ACCOUNT --> account
previousNode().saRevRedeem.clear (saPrvRedeemReq);
previousNode().saRevIssue.clear (saPrvIssueReq);
// redeem (part 1) -> redeem
if (node().saRevRedeem
// Next wants IOUs redeemed from current account.
&& saPrvRedeemReq)
// Previous has IOUs to redeem to the current account.
{
// TODO(tom): add English.
// Rate : 1.0 : quality out - we must accept our own IOUs
// as 1:1.
rippleLiquidity (
rippleCalc_,
parityRate,
qualityOut,
saPrvRedeemReq,
node().saRevRedeem,
previousNode().saRevRedeem,
saCurRedeemAct,
uRateMax);
JLOG (j_.trace())
<< "reverseLiquidityForAccount: "
<< "Rate : 1.0 : quality out"
<< " previousNode.saRevRedeem:" << previousNode().saRevRedeem
<< " saCurRedeemAct:" << saCurRedeemAct;
}
// issue (part 1) -> redeem
if (node().saRevRedeem != saCurRedeemAct
// The current node has more IOUs to redeem.
&& previousNode().saRevRedeem == saPrvRedeemReq)
// The previous node has no IOUs to redeem remaining, so issues.
{
// Rate: quality in : quality out
rippleLiquidity (
rippleCalc_,
qualityIn,
qualityOut,
saPrvIssueReq,
node().saRevRedeem,
previousNode().saRevIssue,
saCurRedeemAct,
uRateMax);
JLOG (j_.trace())
<< "reverseLiquidityForAccount: "
<< "Rate: quality in : quality out:"
<< " previousNode.saRevIssue:" << previousNode().saRevIssue
<< " saCurRedeemAct:" << saCurRedeemAct;
}
// redeem (part 2) -> issue.
if (node().saRevIssue // Next wants IOUs issued.
// TODO(tom): this condition seems redundant.
&& saCurRedeemAct == node().saRevRedeem
// Can only issue if completed redeeming.
&& previousNode().saRevRedeem != saPrvRedeemReq)
// Did not complete redeeming previous IOUs.
{
// Rate : 1.0 : transfer_rate
rippleLiquidity (
rippleCalc_,
parityRate,
transferRate (view(), node().account_),
saPrvRedeemReq,
node().saRevIssue,
previousNode().saRevRedeem,
saCurIssueAct,
uRateMax);
JLOG (j_.debug())
<< "reverseLiquidityForAccount: "
<< "Rate : 1.0 : transfer_rate:"
<< " previousNode.saRevRedeem:" << previousNode().saRevRedeem
<< " saCurIssueAct:" << saCurIssueAct;
}
// issue (part 2) -> issue
if (node().saRevIssue != saCurIssueAct
// Need wants more IOUs issued.
&& saCurRedeemAct == node().saRevRedeem
// Can only issue if completed redeeming.
&& saPrvRedeemReq == previousNode().saRevRedeem
// Previously redeemed all owed IOUs.
&& saPrvIssueReq)
// Previous can issue.
{
// Rate: quality in : 1.0
rippleLiquidity (
rippleCalc_,
qualityIn,
parityRate,
saPrvIssueReq,
node().saRevIssue,
previousNode().saRevIssue,
saCurIssueAct,
uRateMax);
JLOG (j_.trace())
<< "reverseLiquidityForAccount: "
<< "Rate: quality in : 1.0:"
<< " previousNode.saRevIssue:" << previousNode().saRevIssue
<< " saCurIssueAct:" << saCurIssueAct;
}
if (!saCurRedeemAct && !saCurIssueAct)
{
// Did not make progress.
terResult = tecPATH_DRY;
}
JLOG (j_.trace())
<< "reverseLiquidityForAccount: "
<< "^|account --> ACCOUNT --> account :"
<< " node.saRevRedeem:" << node().saRevRedeem
<< " node.saRevIssue:" << node().saRevIssue
<< " saPrvOwed:" << saPrvOwed
<< " saCurRedeemAct:" << saCurRedeemAct
<< " saCurIssueAct:" << saCurIssueAct;
}
}
else if (previousNodeIsAccount && !nextNodeIsAccount)
{
// account --> ACCOUNT --> offer
// Note: deliver is always issue as ACCOUNT is the issuer for the offer
// input.
JLOG (j_.trace())
<< "reverseLiquidityForAccount: "
<< "account --> ACCOUNT --> offer";
previousNode().saRevRedeem.clear (saPrvRedeemReq);
previousNode().saRevIssue.clear (saPrvIssueReq);
// We have three cases: the nxt offer can be owned by current account,
// previous account or some third party account.
//
// Also, the current account may or may not have a redeemable balance
// with the account for the next offer, so we don't yet know if we're
// redeeming or issuing.
//
// TODO(tom): Make sure deliver was cleared, or check actual is zero.
// redeem -> deliver/issue.
if (saPrvOwed > beast::zero // Previous has IOUs to redeem.
&& node().saRevDeliver) // Need some issued.
{
// Rate : 1.0 : transfer_rate
rippleLiquidity (
rippleCalc_,
parityRate,
transferRate (view(), node().account_),
saPrvRedeemReq,
node().saRevDeliver,
previousNode().saRevRedeem,
saCurDeliverAct,
uRateMax);
}
// issue -> deliver/issue
if (saPrvRedeemReq == previousNode().saRevRedeem
// Previously redeemed all owed.
&& node().saRevDeliver != saCurDeliverAct) // Still need some issued.
{
// Rate: quality in : 1.0
rippleLiquidity (
rippleCalc_,
qualityIn,
parityRate,
saPrvIssueReq,
node().saRevDeliver,
previousNode().saRevIssue,
saCurDeliverAct,
uRateMax);
}
if (!saCurDeliverAct)
{
// Must want something.
terResult = tecPATH_DRY;
}
JLOG (j_.trace())
<< "reverseLiquidityForAccount: "
<< " node.saRevDeliver:" << node().saRevDeliver
<< " saCurDeliverAct:" << saCurDeliverAct
<< " saPrvOwed:" << saPrvOwed;
}
else if (!previousNodeIsAccount && nextNodeIsAccount)
{
if (isFinalNode)
{
// offer --> ACCOUNT --> $
// Previous is an offer, no limit: redeem own IOUs.
//
// This is the final node; we can't look to the right to get values;
// we have to go up to get the out value for the entire path state.
STAmount const& saCurWantedReq =
pathState_.outReq() - pathState_.outAct();
STAmount saCurWantedAct = saCurWantedReq.zeroed();
JLOG (j_.trace())
<< "reverseLiquidityForAccount: "
<< "offer --> ACCOUNT --> $ :"
<< " saCurWantedReq:" << saCurWantedReq
<< " saOutAct:" << pathState_.outAct()
<< " saOutReq:" << pathState_.outReq();
if (saCurWantedReq <= beast::zero)
{
assert(false);
JLOG (j_.fatal()) << "CurWantReq was not positive";
return tefEXCEPTION;
}
// The previous node is an offer; we are receiving our own currency.
// The previous order book's entries might hold our issuances; might
// not hold our issuances; might be our own offer.
//
// Assume the worst case, the case which costs the most to go
// through, which is that it is not our own offer or our own
// issuances. Later on the forward pass we may be able to do
// better.
//
// TODO: this comment applies generally to this section - move it up
// to a document.
// Rate: quality in : 1.0
rippleLiquidity (
rippleCalc_,
qualityIn,
parityRate,
saPrvDeliverReq,
saCurWantedReq,
previousNode().saRevDeliver,
saCurWantedAct,
uRateMax);
if (!saCurWantedAct)
{
// Must have processed something.
terResult = tecPATH_DRY;
}
JLOG (j_.trace())
<< "reverseLiquidityForAccount:"
<< " previousNode().saRevDeliver:" << previousNode().saRevDeliver
<< " saPrvDeliverReq:" << saPrvDeliverReq
<< " saCurWantedAct:" << saCurWantedAct
<< " saCurWantedReq:" << saCurWantedReq;
}
else
{
// offer --> ACCOUNT --> account
// Note: offer is always delivering(redeeming) as account is issuer.
JLOG (j_.trace())
<< "reverseLiquidityForAccount: "
<< "offer --> ACCOUNT --> account :"
<< " node.saRevRedeem:" << node().saRevRedeem
<< " node.saRevIssue:" << node().saRevIssue;
// deliver -> redeem
// TODO(tom): now we have more checking in nodeRipple, these checks
// might be redundant.
if (node().saRevRedeem) // Next wants us to redeem.
{
// cur holds IOUs from the account to the right, the nxt
// account. If someone is making the current account get rid of
// the nxt account's IOUs, then charge the input for quality
// out.
//
// Rate : 1.0 : quality out
rippleLiquidity (
rippleCalc_,
parityRate,
qualityOut,
saPrvDeliverReq,
node().saRevRedeem,
previousNode().saRevDeliver,
saCurRedeemAct,
uRateMax);
}
// deliver -> issue.
if (node().saRevRedeem == saCurRedeemAct
// Can only issue if previously redeemed all.
&& node().saRevIssue)
// Need some issued.
{
// Rate : 1.0 : transfer_rate
rippleLiquidity (
rippleCalc_,
parityRate,
transferRate (view(), node().account_),
saPrvDeliverReq,
node().saRevIssue,
previousNode().saRevDeliver,
saCurIssueAct,
uRateMax);
}
JLOG (j_.trace())
<< "reverseLiquidityForAccount:"
<< " saCurRedeemAct:" << saCurRedeemAct
<< " node.saRevRedeem:" << node().saRevRedeem
<< " previousNode.saRevDeliver:" << previousNode().saRevDeliver
<< " node.saRevIssue:" << node().saRevIssue;
if (!previousNode().saRevDeliver)
{
// Must want something.
terResult = tecPATH_DRY;
}
}
}
else
{
// offer --> ACCOUNT --> offer
// deliver/redeem -> deliver/issue.
JLOG (j_.trace())
<< "reverseLiquidityForAccount: offer --> ACCOUNT --> offer";
// Rate : 1.0 : transfer_rate
rippleLiquidity (
rippleCalc_,
parityRate,
transferRate (view(), node().account_),
saPrvDeliverReq,
node().saRevDeliver,
previousNode().saRevDeliver,
saCurDeliverAct,
uRateMax);
if (!saCurDeliverAct)
{
// Must want something.
terResult = tecPATH_DRY;
}
}
return terResult;
}
