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Add support for multiple path finding and path length limiting.

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This commit is contained in:
Arthur Britto
2012-12-11 15:31:55 -08:00
parent 154f4bc980
commit eac6fe88c1
3 changed files with 108 additions and 61 deletions
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163
src/cpp/ripple/Pathfinder.cpp
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@@ -75,6 +75,11 @@ PathOption::PathOption(PathOption::pointer other)
}
#endif
static bool bQualityCmp(std::pair<uint32, unsigned int> a, std::pair<uint32, unsigned int> b)
{
return a.first < b.first;
}
// Return true, if path is a default path with an element.
// A path is a default path if it is implied via src, dst, send, and sendmax.
bool Pathfinder::bDefaultPath(const STPath& spPath)
@@ -150,17 +155,17 @@ Pathfinder::Pathfinder(const RippleAddress& uSrcAccountID, const RippleAddress&
}
// If possible, returns a single path.
// --> maxSearchSteps: unused XXX
// --> maxPay: unused XXX
// --> iMaxSteps: Maximum nodes in paths to return.
// --> iMaxPaths: Maximum number of paths to return.
// <-- retPathSet: founds paths not including default paths.
// Returns true if found paths.
//
// When generating a path set blindly, don't allow the empty path, it is implied by default.
// When generating a path set for estimates, allow an empty path instead of no paths to indicate a path exists. The caller will
// need to strip the empty path when submitting the transaction.
bool Pathfinder::findPaths(int maxSearchSteps, int maxPay, STPathSet& retPathSet)
bool Pathfinder::findPaths(const unsigned int iMaxSteps, const unsigned int iMaxPaths, STPathSet& spsDst)
{
bool bFound = false;
bool bFound = false; // True, iff found a path.
cLog(lsDEBUG) << boost::str(boost::format("findPaths> mSrcAccountID=%s mDstAccountID=%s mDstAmount=%s mSrcCurrencyID=%s mSrcIssuerID=%s")
% RippleAddress::createHumanAccountID(mSrcAccountID)
@@ -172,72 +177,85 @@ bool Pathfinder::findPaths(int maxSearchSteps, int maxPay, STPathSet& retPathSet
if (mLedger)
{
std::queue<STPath> pqueue;
STPathElement ele(mSrcAccountID,
mSrcCurrencyID,
uint160()); // XXX Might add source issuer.
std::vector<STPath> vspResults;
std::queue<STPath> qspExplore;
STPathElement speEnd(mSrcAccountID,
mSrcCurrencyID,
uint160()); // XXX Might add source issuer.
STPath path;
path.addElement(ele); // Add the source.
path.addElement(speEnd); // Add the source.
pqueue.push(path);
qspExplore.push(path);
while (pqueue.size()) {
STPath path = pqueue.front();
while (qspExplore.size()) {
STPath spPath = qspExplore.front();
pqueue.pop(); // Pop the first path from the queue.
qspExplore.pop(); // Pop the first path from the queue.
ele = path.mPath.back(); // Get the last node from the path.
speEnd = spPath.mPath.back(); // Get the last node from the path.
// Done, if dest wants XRP and last element produces XRP.
if (!ele.mCurrencyID // Tail output is XRP.
if (!speEnd.mCurrencyID // Tail output is XRP.
&& !mDstAmount.getCurrency()) { // Which is dst currency.
// Remove implied first.
path.mPath.erase(path.mPath.begin());
spPath.mPath.erase(spPath.mPath.begin());
if (path.size())
if (spPath.size())
{
// There is an actual path element.
retPathSet.addPath(path); // Return the path.
vspResults.push_back(spPath); // Potential result.
cLog(lsDEBUG) << "findPaths: adding: " << path.getJson(0);
cLog(lsDEBUG) << "findPaths: adding: " << spPath.getJson(0);
}
else
{
cLog(lsDEBUG) << "findPaths: empty path: XRP->XRP";
}
return true;
continue;
}
// Done, if dest wants non-XRP and last element is dest.
// YYY Allows going through self. Is this wanted?
if (ele.mAccountID == mDstAccountID // Tail is destination account.
&& ele.mCurrencyID == mDstAmount.getCurrency()) { // With correct output currency.
if (speEnd.mAccountID == mDstAccountID // Tail is destination account.
&& speEnd.mCurrencyID == mDstAmount.getCurrency()) { // With correct output currency.
// Found a path to the destination.
if (bDefaultPath(path)) {
cLog(lsDEBUG) << "findPaths: default path: dropping: " << path.getJson(0);
return true;
if (bDefaultPath(spPath)) {
cLog(lsDEBUG) << "findPaths: default path: dropping: " << spPath.getJson(0);
bFound = true;
}
else
{
// Remove implied first and last nodes.
spPath.mPath.erase(spPath.mPath.begin());
spPath.mPath.erase(spPath.mPath.begin() + spPath.mPath.size()-1);
vspResults.push_back(spPath); // Potential result.
cLog(lsDEBUG) << "findPaths: adding: " << spPath.getJson(0);
}
// Remove implied first and last nodes.
path.mPath.erase(path.mPath.begin());
path.mPath.erase(path.mPath.begin() + path.mPath.size()-1);
// Return the path.
retPathSet.addPath(path);
cLog(lsDEBUG) << "findPaths: adding: " << path.getJson(0);
return true;
continue;
}
bool bContinued = false;
if (!ele.mCurrencyID) {
if (spPath.mPath.size() == iMaxSteps)
{
// Path is at maximum size. Don't want to add more.
cLog(lsDEBUG)
<< boost::str(boost::format("findPaths: path would exceed max steps: dropping"));
}
else if (!speEnd.mCurrencyID)
{
// Last element is for XRP continue with qualifying books.
BOOST_FOREACH(OrderBook::pointer book, mOrderBook.getXRPInBooks())
{
@@ -245,7 +263,7 @@ bool Pathfinder::findPaths(int maxSearchSteps, int maxPay, STPathSet& retPathSet
//if (!path.hasSeen(line->getAccountIDPeer().getAccountID()))
{
STPath new_path(path);
STPath new_path(spPath);
STPathElement new_ele(uint160(), book->getCurrencyOut(), book->getIssuerOut());
new_path.mPath.push_back(new_ele);
@@ -257,7 +275,7 @@ bool Pathfinder::findPaths(int maxSearchSteps, int maxPay, STPathSet& retPathSet
% STAmount::createHumanCurrency(new_path.mCurrencyID)
% RippleAddress::createHumanAccountID(new_path.mCurrentAccount));
pqueue.push(new_path);
qspExplore.push(new_path);
bContinued = true;
}
@@ -265,33 +283,34 @@ bool Pathfinder::findPaths(int maxSearchSteps, int maxPay, STPathSet& retPathSet
tLog(!bContinued, lsDEBUG)
<< boost::str(boost::format("findPaths: XRP input - dead end"));
} else {
}
else
{
// Last element is for non-XRP continue by adding ripple lines and order books.
// Create new paths for each outbound account not already in the path.
AccountItems rippleLines(ele.mAccountID, mLedger, AccountItem::pointer(new RippleState()));
AccountItems rippleLines(speEnd.mAccountID, mLedger, AccountItem::pointer(new RippleState()));
BOOST_FOREACH(AccountItem::pointer item, rippleLines.getItems())
{
RippleState* line=(RippleState*)item.get();
if (!path.hasSeen(line->getAccountIDPeer().getAccountID()))
if (!spPath.hasSeen(line->getAccountIDPeer().getAccountID()))
{
STPath new_path(path);
STPath new_path(spPath);
STPathElement new_ele(line->getAccountIDPeer().getAccountID(),
ele.mCurrencyID,
speEnd.mCurrencyID,
uint160());
cLog(lsDEBUG) <<
boost::str(boost::format("findPaths: %s/%s --> %s/%s")
% RippleAddress::createHumanAccountID(ele.mAccountID)
% STAmount::createHumanCurrency(ele.mCurrencyID)
% RippleAddress::createHumanAccountID(speEnd.mAccountID)
% STAmount::createHumanCurrency(speEnd.mCurrencyID)
% RippleAddress::createHumanAccountID(line->getAccountIDPeer().getAccountID())
% STAmount::createHumanCurrency(ele.mCurrencyID));
% STAmount::createHumanCurrency(speEnd.mCurrencyID));
new_path.mPath.push_back(new_ele);
pqueue.push(new_path);
qspExplore.push(new_path);
bContinued = true;
}
@@ -299,27 +318,27 @@ bool Pathfinder::findPaths(int maxSearchSteps, int maxPay, STPathSet& retPathSet
{
cLog(lsDEBUG) <<
boost::str(boost::format("findPaths: SEEN: %s/%s --> %s/%s")
% RippleAddress::createHumanAccountID(ele.mAccountID)
% STAmount::createHumanCurrency(ele.mCurrencyID)
% RippleAddress::createHumanAccountID(speEnd.mAccountID)
% STAmount::createHumanCurrency(speEnd.mCurrencyID)
% RippleAddress::createHumanAccountID(line->getAccountIDPeer().getAccountID())
% STAmount::createHumanCurrency(ele.mCurrencyID));
% STAmount::createHumanCurrency(speEnd.mCurrencyID));
}
}
// Every book that wants the source currency.
std::vector<OrderBook::pointer> books;
mOrderBook.getBooks(path.mCurrentAccount, path.mCurrencyID, books);
mOrderBook.getBooks(spPath.mCurrentAccount, spPath.mCurrencyID, books);
BOOST_FOREACH(OrderBook::pointer book,books)
{
STPath new_path(path);
STPath new_path(spPath);
STPathElement new_ele(uint160(), book->getCurrencyOut(), book->getIssuerOut());
cLog(lsDEBUG) <<
boost::str(boost::format("findPaths: %s/%s :: %s/%s")
% STAmount::createHumanCurrency(ele.mCurrencyID)
% RippleAddress::createHumanAccountID(ele.mAccountID)
% STAmount::createHumanCurrency(speEnd.mCurrencyID)
% RippleAddress::createHumanAccountID(speEnd.mAccountID)
% STAmount::createHumanCurrency(book->getCurrencyOut())
% RippleAddress::createHumanAccountID(book->getIssuerOut()));
@@ -327,14 +346,42 @@ bool Pathfinder::findPaths(int maxSearchSteps, int maxPay, STPathSet& retPathSet
new_path.mCurrentAccount=book->getIssuerOut();
new_path.mCurrencyID=book->getCurrencyOut();
pqueue.push(new_path);
qspExplore.push(new_path);
bContinued = true;
}
tLog(!bContinued, lsDEBUG)
<< boost::str(boost::format("findPaths: non-XRP input - dead end"));
}
}
unsigned int iLimit = std::min(iMaxPaths, (unsigned int) vspResults.size());
if (iLimit)
{
std::vector< std::pair<uint32, unsigned int> > vMap;
// Build map of quality to entry.
for (int i = vspResults.size(); i--;)
{
uint32 uQuality = 1;
if (uQuality)
vMap.push_back(std::make_pair(uQuality, i));
}
tLog(!bContinued, lsDEBUG)
<< boost::str(boost::format("findPaths: non-XRP input - dead end"));
std::sort(vMap.begin(), vMap.end(), bQualityCmp);
// Output best quality entries.
for (int i = 0; i != iLimit; ++i)
{
spsDst.addPath(vspResults[vMap[i].second]);
}
bFound = true;
cLog(lsWARNING) << boost::str(boost::format("findPaths: RESULTS: %s") % spsDst.getJson(0));
}
}
else