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Use enums for some parameters in payments:

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* Use enums for StrandDirection, DebtDirection, and QualityDirection
This commit is contained in:
seelabs
2019-07-29 13:17:26 -07:00
committed by Nik Bougalis
parent c217baa367
commit 561942da23
5 changed files with 206 additions and 138 deletions
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48
src/ripple/app/paths/impl/BookStep.cpp
View File

@@ -110,10 +110,11 @@ public:
return EitherAmount (cache_->out);
}
bool
redeems (ReadView const& sb, bool fwd) const override
DebtDirection
debtDirection(ReadView const& sb, StrandDirection dir) const override
{
return !ownerPaysTransferFee_;
return ownerPaysTransferFee_ ? DebtDirection::issues
: DebtDirection::redeems;
}
boost::optional<Book>
@@ -123,7 +124,7 @@ public:
}
boost::optional<Quality>
qualityUpperBound(ReadView const& v, bool& redeems) const override;
qualityUpperBound(ReadView const& v, DebtDirection& dir) const override;
std::pair<TIn, TOut>
revImp (
@@ -188,7 +189,7 @@ private:
forEachOffer (
PaymentSandbox& sb,
ApplyView& afView,
bool prevStepRedeems,
DebtDirection prevStepDebtDir,
Callback& callback) const;
void consumeOffer (PaymentSandbox& sb,
@@ -248,7 +249,7 @@ public:
Quality
qualityUpperBound(ReadView const& v,
Quality const& ofrQ,
bool prevStepRedeems) const
DebtDirection prevStepDir) const
{
// Charge the offer owner, not the sender
// Charge a fee even if the owner is the same as the issuer
@@ -262,7 +263,7 @@ public:
};
auto const trIn =
prevStepRedeems ? rate(this->book_.in.account) : parityRate;
redeems(prevStepDir) ? rate(this->book_.in.account) : parityRate;
// Always charge the transfer fee, even if the owner is the issuer
auto const trOut =
this->ownerPaysTransferFee_
@@ -393,7 +394,7 @@ public:
Quality
qualityUpperBound(ReadView const& v,
Quality const& ofrQ,
bool prevStepRedeems) const
DebtDirection prevStepDir) const
{
// Offer x-ing does not charge a transfer fee when the offer's owner
// is the same as the strand dst. It is important that `qualityUpperBound`
@@ -427,10 +428,10 @@ bool BookStep<TIn, TOut, TDerived>::equal (Step const& rhs) const
template <class TIn, class TOut, class TDerived>
boost::optional<Quality>
BookStep<TIn, TOut, TDerived>::qualityUpperBound(
ReadView const& v, bool& redeems) const
ReadView const& v, DebtDirection& dir) const
{
auto const prevStepRedeems = redeems;
redeems = this->redeems(v, true);
auto const prevStepDir = dir;
dir = this->debtDirection(v, StrandDirection::forward);
// This can be simplified (and sped up) if directories are never empty.
Sandbox sb(&v, tapNONE);
@@ -439,7 +440,7 @@ BookStep<TIn, TOut, TDerived>::qualityUpperBound(
return boost::none;
return static_cast<TDerived const*>(this)->qualityUpperBound(
v, bt.quality(), prevStepRedeems);
v, bt.quality(), prevStepDir);
}
// Adjust the offer amount and step amount subject to the given input limit
@@ -493,7 +494,7 @@ std::pair<boost::container::flat_set<uint256>, std::uint32_t>
BookStep<TIn, TOut, TDerived>::forEachOffer (
PaymentSandbox& sb,
ApplyView& afView,
bool prevStepRedeems,
DebtDirection prevStepDir,
Callback& callback) const
{
// Charge the offer owner, not the sender
@@ -507,9 +508,8 @@ BookStep<TIn, TOut, TDerived>::forEachOffer (
return transferRate (sb, id).value;
};
std::uint32_t const trIn = prevStepRedeems
? rate (book_.in.account)
: QUALITY_ONE;
std::uint32_t const trIn =
redeems(prevStepDir) ? rate(book_.in.account) : QUALITY_ONE;
// Always charge the transfer fee, even if the owner is the issuer
std::uint32_t const trOut = ownerPaysTransferFee_
? rate (book_.out.account)
@@ -726,8 +726,12 @@ BookStep<TIn, TOut, TDerived>::revImp (
};
{
auto const prevStepRedeems = prevStep_ && prevStep_->redeems (sb, false);
auto const r = forEachOffer (sb, afView, prevStepRedeems, eachOffer);
auto const prevStepDebtDir = [&]{
if (prevStep_)
return prevStep_->debtDirection (sb, StrandDirection::reverse);
return DebtDirection::issues;
}();
auto const r = forEachOffer (sb, afView, prevStepDebtDir, eachOffer);
boost::container::flat_set<uint256> toRm = std::move(std::get<0>(r));
std::uint32_t const offersConsumed = std::get<1>(r);
SetUnion(ofrsToRm, toRm);
@@ -887,8 +891,12 @@ BookStep<TIn, TOut, TDerived>::fwdImp (
};
{
auto const prevStepRedeems = prevStep_ && prevStep_->redeems (sb, true);
auto const r = forEachOffer (sb, afView, prevStepRedeems, eachOffer);
auto const prevStepDebtDir = [&] {
if (prevStep_)
return prevStep_->debtDirection(sb, StrandDirection::forward);
return DebtDirection::issues;
}();
auto const r = forEachOffer(sb, afView, prevStepDebtDir, eachOffer);
boost::container::flat_set<uint256> toRm = std::move(std::get<0>(r));
std::uint32_t const offersConsumed = std::get<1>(r);
SetUnion(ofrsToRm, toRm);

222
src/ripple/app/paths/impl/DirectStep.cpp
View File

@@ -26,6 +26,7 @@
#include <ripple/protocol/Quality.h>
#include <boost/container/flat_set.hpp>
#include <boost/optional.hpp>
#include <numeric>
#include <sstream>
@@ -50,17 +51,17 @@ protected:
IOUAmount in;
IOUAmount srcToDst;
IOUAmount out;
bool srcRedeems;
DebtDirection srcDebtDir;
Cache (
IOUAmount const& in_,
IOUAmount const& srcToDst_,
IOUAmount const& out_,
bool srcRedeems_)
DebtDirection srcDebtDir_)
: in(in_)
, srcToDst(srcToDst_)
, out(out_)
, srcRedeems(srcRedeems_)
, srcDebtDir(srcDebtDir_)
{}
};
@@ -69,17 +70,28 @@ protected:
// Compute the maximum value that can flow from src->dst at
// the best available quality.
// return: first element is max amount that can flow,
// second is true if dst holds an iou from src.
std::pair<IOUAmount, bool>
// second is the debt direction of the source w.r.t. the dst
std::pair<IOUAmount, DebtDirection>
maxPaymentFlow (
ReadView const& sb) const;
// Compute srcQOut and dstQIn when the source redeems.
std::pair<std::uint32_t, std::uint32_t>
qualitiesSrcRedeems(
ReadView const& sb) const;
// Compute srcQOut and dstQIn when the source issues.
std::pair<std::uint32_t, std::uint32_t>
qualitiesSrcIssues(
ReadView const& sb,
DebtDirection prevStepDebtDirection) const;
// Returns srcQOut, dstQIn
std::pair <std::uint32_t, std::uint32_t>
qualities (
ReadView const& sb,
bool srcRedeems,
bool fwd) const;
DebtDirection srcDebtDir,
StrandDirection strandDir) const;
public:
DirectStepI (
@@ -135,14 +147,14 @@ public:
return std::make_pair(src_, dst_);
}
bool
redeems (ReadView const& sb, bool fwd) const override;
DebtDirection
debtDirection (ReadView const& sb, StrandDirection dir) const override;
std::uint32_t
lineQualityIn (ReadView const& v) const override;
boost::optional<Quality>
qualityUpperBound(ReadView const& v, bool& redeems) const override;
qualityUpperBound(ReadView const& v, DebtDirection& dir) const override;
std::pair<IOUAmount, IOUAmount>
revImp (
@@ -172,7 +184,7 @@ public:
IOUAmount const& fwdIn,
IOUAmount const& fwdSrcToDst,
IOUAmount const& fwdOut,
bool srcRedeems);
DebtDirection srcDebtDir);
friend bool operator==(DirectStepI const& lhs, DirectStepI const& rhs)
{
@@ -223,7 +235,7 @@ public:
using DirectStepI<DirectIPaymentStep>::DirectStepI;
using DirectStepI<DirectIPaymentStep>::check;
bool verifyPrevStepRedeems (bool) const
bool verifyPrevStepDebtDirection (DebtDirection) const
{
// A payment doesn't care whether or not prevStepRedeems.
return true;
@@ -237,14 +249,13 @@ public:
std::uint32_t
quality (ReadView const& sb,
// set true for quality in, false for quality out
bool qin) const;
QualityDirection qDir) const;
// Compute the maximum value that can flow from src->dst at
// the best available quality.
// return: first element is max amount that can flow,
// second is true if dst holds an iou from src.
std::pair<IOUAmount, bool>
// second is the debt direction w.r.t. the source account
std::pair<IOUAmount, DebtDirection>
maxFlow (ReadView const& sb, IOUAmount const& desired) const;
// Verify the consistency of the step. These checks are specific to
@@ -266,15 +277,15 @@ public:
using DirectStepI<DirectIOfferCrossingStep>::DirectStepI;
using DirectStepI<DirectIOfferCrossingStep>::check;
bool verifyPrevStepRedeems (bool prevStepRedeems) const
bool verifyPrevStepDebtDirection (DebtDirection prevStepDir) const
{
// During offer crossing we rely on the fact that prevStepRedeems
// will *always* be false. That's because:
// will *always* issue. That's because:
// o If there's a prevStep_, it will always be a BookStep.
// o BookStep::redeems() aways returns false when offer crossing.
// o BookStep::debtDirection() aways returns `issues` when offer crossing.
// An assert based on this return value will tell us if that
// behavior changes.
return !prevStepRedeems;
return issues(prevStepDir);
}
bool verifyDstQualityIn (std::uint32_t dstQIn) const
@@ -286,14 +297,13 @@ public:
std::uint32_t
quality (ReadView const& sb,
// set true for quality in, false for quality out
bool qin) const;
QualityDirection qDir) const;
// Compute the maximum value that can flow from src->dst at
// the best available quality.
// return: first element is max amount that can flow,
// second is true if dst holds an iou from src.
std::pair<IOUAmount, bool>
// second is the debt direction w.r.t the source
std::pair<IOUAmount, DebtDirection>
maxFlow (ReadView const& sb, IOUAmount const& desired) const;
// Verify the consistency of the step. These checks are specific to
@@ -313,8 +323,7 @@ public:
std::uint32_t
DirectIPaymentStep::quality (ReadView const& sb,
// set true for quality in, false for quality out
bool qin) const
QualityDirection qDir) const
{
if (src_ == dst_)
return QUALITY_ONE;
@@ -324,9 +333,9 @@ DirectIPaymentStep::quality (ReadView const& sb,
if (!sle)
return QUALITY_ONE;
auto const& field = [this, qin]() -> SF_U32 const&
auto const& field = [this, qDir]() -> SF_U32 const&
{
if (qin)
if (qDir == QualityDirection::in)
{
// compute dst quality in
if (this->dst_ < this->src_)
@@ -355,21 +364,20 @@ DirectIPaymentStep::quality (ReadView const& sb,
std::uint32_t
DirectIOfferCrossingStep::quality (ReadView const&,
// set true for quality in, false for quality out
bool) const
QualityDirection qDir) const
{
// If offer crossing then ignore trust line Quality fields. This
// preserves a long-standing tradition.
return QUALITY_ONE;
}
std::pair<IOUAmount, bool>
std::pair<IOUAmount, DebtDirection>
DirectIPaymentStep::maxFlow (ReadView const& sb, IOUAmount const&) const
{
return maxPaymentFlow (sb);
}
std::pair<IOUAmount, bool>
std::pair<IOUAmount, DebtDirection>
DirectIOfferCrossingStep::maxFlow (
ReadView const& sb, IOUAmount const& desired) const
{
@@ -386,7 +394,7 @@ DirectIOfferCrossingStep::maxFlow (
// "dstQIn" is always QUALITY_ONE for offer crossing.
if (isLast_)
return {desired, false};
return {desired, DebtDirection::issues};
return maxPaymentFlow (sb);
}
@@ -460,29 +468,31 @@ DirectIOfferCrossingStep::check (
//------------------------------------------------------------------------------
template <class TDerived>
std::pair<IOUAmount, bool>
std::pair<IOUAmount, DebtDirection>
DirectStepI<TDerived>::maxPaymentFlow (ReadView const& sb) const
{
auto const srcOwed = toAmount<IOUAmount> (
accountHolds (sb, src_, currency_, dst_, fhIGNORE_FREEZE, j_));
if (srcOwed.signum () > 0)
return {srcOwed, true};
return {srcOwed, DebtDirection::redeems};
// srcOwed is negative or zero
return {creditLimit2 (sb, dst_, src_, currency_) + srcOwed, false};
return {creditLimit2 (sb, dst_, src_, currency_) + srcOwed, DebtDirection::issues};
}
template <class TDerived>
bool
DirectStepI<TDerived>::redeems (ReadView const& sb, bool fwd) const
DebtDirection
DirectStepI<TDerived>::debtDirection(ReadView const& sb, StrandDirection dir)
const
{
if (fwd && cache_)
return cache_->srcRedeems;
if (dir == StrandDirection::forward && cache_)
return cache_->srcDebtDir;
auto const srcOwed = accountHolds (
sb, src_, currency_, dst_, fhIGNORE_FREEZE, j_);
return srcOwed.signum () > 0;
auto const srcOwed =
accountHolds(sb, src_, currency_, dst_, fhIGNORE_FREEZE, j_);
return srcOwed.signum() > 0 ? DebtDirection::redeems
: DebtDirection::issues;
}
template <class TDerived>
@@ -495,21 +505,22 @@ DirectStepI<TDerived>::revImp (
{
cache_.reset ();
bool srcRedeems;
DebtDirection srcDebtDir;
IOUAmount maxSrcToDst;
std::tie (maxSrcToDst, srcRedeems) =
std::tie (maxSrcToDst, srcDebtDir) =
static_cast<TDerived const*>(this)->maxFlow (sb, out);
std::uint32_t srcQOut, dstQIn;
std::tie (srcQOut, dstQIn) = qualities (sb, srcRedeems, false);
std::tie (srcQOut, dstQIn) = qualities (sb, srcDebtDir, StrandDirection::reverse);
assert (static_cast<TDerived const*>(this)->verifyDstQualityIn (dstQIn));
Issue const srcToDstIss (currency_, srcRedeems ? dst_ : src_);
Issue const srcToDstIss(
currency_, redeems(srcDebtDir) ? dst_ : src_);
JLOG (j_.trace()) <<
"DirectStepI::rev" <<
" srcRedeems: " << srcRedeems <<
" srcRedeems: " << redeems(srcDebtDir) <<
" outReq: " << to_string (out) <<
" maxSrcToDst: " << to_string (maxSrcToDst) <<
" srcQOut: " << srcQOut <<
@@ -522,7 +533,7 @@ DirectStepI<TDerived>::revImp (
IOUAmount (beast::zero),
IOUAmount (beast::zero),
IOUAmount (beast::zero),
srcRedeems);
srcDebtDir);
return {beast::zero, beast::zero};
}
@@ -533,13 +544,13 @@ DirectStepI<TDerived>::revImp (
{
IOUAmount const in = mulRatio (
srcToDst, srcQOut, QUALITY_ONE, /*roundUp*/ true);
cache_.emplace (in, srcToDst, out, srcRedeems);
cache_.emplace (in, srcToDst, out, srcDebtDir);
rippleCredit (sb,
src_, dst_, toSTAmount (srcToDst, srcToDstIss),
/*checkIssuer*/ true, j_);
JLOG (j_.trace()) <<
"DirectStepI::rev: Non-limiting" <<
" srcRedeems: " << srcRedeems <<
" srcRedeems: " << redeems(srcDebtDir) <<
" in: " << to_string (in) <<
" srcToDst: " << to_string (srcToDst) <<
" out: " << to_string (out);
@@ -551,13 +562,13 @@ DirectStepI<TDerived>::revImp (
maxSrcToDst, srcQOut, QUALITY_ONE, /*roundUp*/ true);
IOUAmount const actualOut = mulRatio (
maxSrcToDst, dstQIn, QUALITY_ONE, /*roundUp*/ false);
cache_.emplace (in, maxSrcToDst, actualOut, srcRedeems);
cache_.emplace (in, maxSrcToDst, actualOut, srcDebtDir);
rippleCredit (sb,
src_, dst_, toSTAmount (maxSrcToDst, srcToDstIss),
/*checkIssuer*/ true, j_);
JLOG (j_.trace()) <<
"DirectStepI::rev: Limiting" <<
" srcRedeems: " << srcRedeems <<
" srcRedeems: " << redeems(srcDebtDir) <<
" in: " << to_string (in) <<
" srcToDst: " << to_string (maxSrcToDst) <<
" out: " << to_string (out);
@@ -574,7 +585,7 @@ DirectStepI<TDerived>::setCacheLimiting (
IOUAmount const& fwdIn,
IOUAmount const& fwdSrcToDst,
IOUAmount const& fwdOut,
bool srcRedeems)
DebtDirection srcDebtDir)
{
if (cache_->in < fwdIn)
{
@@ -596,7 +607,7 @@ DirectStepI<TDerived>::setCacheLimiting (
<< " cacheSrcToDst: " << to_string (cache_->srcToDst)
<< " fwdOut: " << to_string (fwdOut)
<< " cacheOut: " << to_string (cache_->out);
cache_.emplace (fwdIn, fwdSrcToDst, fwdOut, srcRedeems);
cache_.emplace (fwdIn, fwdSrcToDst, fwdOut, srcDebtDir);
return;
}
}
@@ -606,7 +617,7 @@ DirectStepI<TDerived>::setCacheLimiting (
cache_->srcToDst = fwdSrcToDst;
if (fwdOut < cache_->out)
cache_->out = fwdOut;
cache_->srcRedeems = srcRedeems;
cache_->srcDebtDir = srcDebtDir;
};
template <class TDerived>
@@ -619,19 +630,19 @@ DirectStepI<TDerived>::fwdImp (
{
assert (cache_);
bool srcRedeems;
DebtDirection srcDebtDir;
IOUAmount maxSrcToDst;
std::tie (maxSrcToDst, srcRedeems) =
std::tie (maxSrcToDst, srcDebtDir) =
static_cast<TDerived const*>(this)->maxFlow (sb, cache_->srcToDst);
std::uint32_t srcQOut, dstQIn;
std::tie (srcQOut, dstQIn) = qualities (sb, srcRedeems, true);
std::tie (srcQOut, dstQIn) = qualities (sb, srcDebtDir, StrandDirection::forward);
Issue const srcToDstIss (currency_, srcRedeems ? dst_ : src_);
Issue const srcToDstIss (currency_, redeems(srcDebtDir) ? dst_ : src_);
JLOG (j_.trace()) <<
"DirectStepI::fwd" <<
" srcRedeems: " << srcRedeems <<
" srcRedeems: " << redeems(srcDebtDir) <<
" inReq: " << to_string (in) <<
" maxSrcToDst: " << to_string (maxSrcToDst) <<
" srcQOut: " << srcQOut <<
@@ -644,7 +655,7 @@ DirectStepI<TDerived>::fwdImp (
IOUAmount (beast::zero),
IOUAmount (beast::zero),
IOUAmount (beast::zero),
srcRedeems);
srcDebtDir);
return {beast::zero, beast::zero};
}
@@ -655,13 +666,13 @@ DirectStepI<TDerived>::fwdImp (
{
IOUAmount const out = mulRatio (
srcToDst, dstQIn, QUALITY_ONE, /*roundUp*/ false);
setCacheLimiting (in, srcToDst, out, srcRedeems);
setCacheLimiting (in, srcToDst, out, srcDebtDir);
rippleCredit (sb,
src_, dst_, toSTAmount (cache_->srcToDst, srcToDstIss),
/*checkIssuer*/ true, j_);
JLOG (j_.trace()) <<
"DirectStepI::fwd: Non-limiting" <<
" srcRedeems: " << srcRedeems <<
" srcRedeems: " << redeems(srcDebtDir) <<
" in: " << to_string (in) <<
" srcToDst: " << to_string (srcToDst) <<
" out: " << to_string (out);
@@ -673,13 +684,13 @@ DirectStepI<TDerived>::fwdImp (
maxSrcToDst, srcQOut, QUALITY_ONE, /*roundUp*/ true);
IOUAmount const out = mulRatio (
maxSrcToDst, dstQIn, QUALITY_ONE, /*roundUp*/ false);
setCacheLimiting (actualIn, maxSrcToDst, out, srcRedeems);
setCacheLimiting (actualIn, maxSrcToDst, out, srcDebtDir);
rippleCredit (sb,
src_, dst_, toSTAmount (cache_->srcToDst, srcToDstIss),
/*checkIssuer*/ true, j_);
JLOG (j_.trace()) <<
"DirectStepI::rev: Limiting" <<
" srcRedeems: " << srcRedeems <<
" srcRedeems: " << redeems(srcDebtDir) <<
" in: " << to_string (actualIn) <<
" srcToDst: " << to_string (srcToDst) <<
" out: " << to_string (out);
@@ -705,9 +716,9 @@ DirectStepI<TDerived>::validFwd (
assert (!in.native);
bool srcRedeems;
DebtDirection srcDebtDir;
IOUAmount maxSrcToDst;
std::tie (maxSrcToDst, srcRedeems) =
std::tie (maxSrcToDst, srcDebtDir) =
static_cast<TDerived const*>(this)->maxFlow (sb, cache_->srcToDst);
try
@@ -747,40 +758,65 @@ DirectStepI<TDerived>::validFwd (
// Returns srcQOut, dstQIn
template <class TDerived>
std::pair<std::uint32_t, std::uint32_t>
DirectStepI<TDerived>::qualities (
ReadView const& sb,
bool srcRedeems,
bool fwd) const
{
if (srcRedeems)
DirectStepI<TDerived>::qualitiesSrcRedeems(
ReadView const& sb) const
{
if (!prevStep_)
return {QUALITY_ONE, QUALITY_ONE};
auto const prevStepQIn = prevStep_->lineQualityIn(sb);
auto srcQOut = static_cast<TDerived const*>(this)->quality (
sb, /* src quality out */ false);
auto srcQOut =
static_cast<TDerived const*>(this)->quality(sb, QualityDirection::out);
if (prevStepQIn > srcQOut)
srcQOut = prevStepQIn;
return {srcQOut, QUALITY_ONE};
}
else
// Returns srcQOut, dstQIn
template <class TDerived>
std::pair<std::uint32_t, std::uint32_t>
DirectStepI<TDerived>::qualitiesSrcIssues(
ReadView const& sb,
DebtDirection prevStepDebtDirection) const
{
// Charge a transfer rate when issuing and previous step redeems
auto const prevStepRedeems = prevStep_ && prevStep_->redeems (sb, fwd);
assert (static_cast<TDerived const*>(this)->verifyPrevStepRedeems (
prevStepRedeems));
std::uint32_t const srcQOut =
prevStepRedeems ? transferRate (sb, src_).value : QUALITY_ONE;
assert(static_cast<TDerived const*>(this)->verifyPrevStepDebtDirection(
prevStepDebtDirection));
std::uint32_t const srcQOut = redeems(prevStepDebtDirection)
? transferRate(sb, src_).value
: QUALITY_ONE;
auto dstQIn = static_cast<TDerived const*>(this)->quality(
sb, /* dst quality in */ true);
sb, QualityDirection::in);
if (isLast_ && dstQIn > QUALITY_ONE)
dstQIn = QUALITY_ONE;
return {srcQOut, dstQIn};
}
// Returns srcQOut, dstQIn
template <class TDerived>
std::pair<std::uint32_t, std::uint32_t>
DirectStepI<TDerived>::qualities(
ReadView const& sb,
DebtDirection srcDebtDir,
StrandDirection strandDir) const
{
if (redeems(srcDebtDir))
{
return qualitiesSrcRedeems(sb);
}
else
{
auto const prevStepDebtDirection = [&] {
if (prevStep_)
return prevStep_->debtDirection(sb, strandDir);
return DebtDirection::issues;
}();
return qualitiesSrcIssues(sb, prevStepDebtDirection);
}
}
template <class TDerived>
@@ -789,19 +825,23 @@ DirectStepI<TDerived>::lineQualityIn (ReadView const& v) const
{
// dst quality in
return static_cast<TDerived const*>(this)->quality (
v, /* dst quality in */ true);
v, QualityDirection::in);
}
template <class TDerived>
boost::optional<Quality>
DirectStepI<TDerived>::qualityUpperBound(ReadView const& v, bool& redeems) const
DirectStepI<TDerived>::qualityUpperBound(ReadView const& v, DebtDirection& dir)
const
{
auto const prevRedeems = redeems;
redeems = this->redeems(v, true);
std::uint32_t const srcQOut =
(prevRedeems && !redeems) ? transferRate(v, src_).value : QUALITY_ONE;
auto dstQIn = static_cast<TDerived const*>(this)->quality (
v, /* dst quality in */ true);
auto const prevStepDebtDir = dir;
dir = this->debtDirection(v, StrandDirection::forward);
std::uint32_t const srcQOut = [&]() -> std::uint32_t {
if (redeems(prevStepDebtDir) && issues(dir))
return transferRate(v, src_).value;
return QUALITY_ONE;
}();
auto dstQIn =
static_cast<TDerived const*>(this)->quality(v, QualityDirection::in);
if (isLast_ && dstQIn > QUALITY_ONE)
dstQIn = QUALITY_ONE;

36
src/ripple/app/paths/impl/Steps.h
View File

@@ -34,6 +34,24 @@ class PaymentSandbox;
class ReadView;
class ApplyView;
enum class DebtDirection { issues, redeems };
enum class QualityDirection { in, out };
enum class StrandDirection { forward, reverse };
inline
bool
redeems(DebtDirection dir)
{
return dir == DebtDirection::redeems;
}
inline
bool
issues(DebtDirection dir)
{
return dir == DebtDirection::issues;
}
/**
A step in a payment path
@@ -63,7 +81,6 @@ class ApplyView;
class Step
{
public:
/** Step destructor. */
virtual ~Step() = default;
/**
@@ -145,13 +162,10 @@ public:
otherwise return true.
@param sb view with the strand's state of balances and offers
@param fwd false -> called from rev(); true -> called from fwd().
@param dir reverse -> called from rev(); forward -> called from fwd().
*/
virtual bool
redeems (ReadView const& sb, bool fwd) const
{
return false;
}
virtual DebtDirection
debtDirection (ReadView const& sb, StrandDirection dir) const = 0;
/**
If this step is a DirectStepI, return the quality in of the dst account.
@@ -166,14 +180,14 @@ public:
Find an upper bound of quality for the step
@param v view to query the ledger state from
@param redeems in/out param. Set to true if the previous step redeems.
Will be set to true if this step redeems; Will be set to false if this
step does not redeem.
@param dir in/out param. Set to DebtDirection::redeems if the previous step redeems.
Will be set to DebtDirection::redeems if this step redeems; Will be set to DebtDirection::issues if this
step does not redeem
@return The upper bound of quality for the step, or boost::none if the
step is dry.
*/
virtual boost::optional<Quality>
qualityUpperBound(ReadView const& v, bool& redeems) const = 0;
qualityUpperBound(ReadView const& v, DebtDirection& dir) const = 0;
/**
If this step is a BookStep, return the book.

4
src/ripple/app/paths/impl/StrandFlow.h
View File

@@ -401,10 +401,10 @@ boost::optional<Quality>
qualityUpperBound(ReadView const& v, Strand const& strand)
{
Quality q{STAmount::uRateOne};
bool redeems = false;
DebtDirection dir = DebtDirection::issues;
for (auto const& step : strand)
{
if (auto const stepQ = step->qualityUpperBound(v, redeems))
if (auto const stepQ = step->qualityUpperBound(v, dir))
q = composed_quality(q, *stepQ);
else
return boost::none;

12
src/ripple/app/paths/impl/XRPEndpointStep.cpp
View File

@@ -89,8 +89,14 @@ public:
return cached ();
}
DebtDirection
debtDirection(ReadView const& sb, StrandDirection dir) const override
{
return DebtDirection::issues;
}
boost::optional<Quality>
qualityUpperBound(ReadView const& v, bool& redeems) const override;
qualityUpperBound(ReadView const& v, DebtDirection& dir) const override;
std::pair<XRPAmount, XRPAmount>
revImp (
@@ -237,9 +243,9 @@ inline bool operator==(XRPEndpointStep<TDerived> const& lhs,
template <class TDerived>
boost::optional<Quality>
XRPEndpointStep<TDerived>::qualityUpperBound(
ReadView const& v, bool& redeems) const
ReadView const& v, DebtDirection& dir) const
{
redeems = this->redeems(v, true);
dir = this->debtDirection(v, StrandDirection::forward);
return Quality{STAmount::uRateOne};
}