From 18b18359c591b9efc90724995e20b9119785c46b Mon Sep 17 00:00:00 2001
From: JoelKatz <DavidJoelSchwartz@GMail.com>
Date: Sat, 8 Sep 2012 04:14:06 -0700
Subject: [PATCH] Be smarter about tracking which peers have which ledgers.

---
 src/Peer.cpp | 20 +++++++++++++++++++-
 src/Peer.h   |  5 ++++-
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/src/Peer.cpp b/src/Peer.cpp
index 27db8ff017..aec3ce31e2 100644
--- a/src/Peer.cpp
+++ b/src/Peer.cpp
@@ -649,7 +649,10 @@ void Peer::recvHello(newcoin::TMHello& packet)
 			{
 				memcpy(mClosedLedgerHash.begin(), packet.ledgerclosed().data(), 256 / 8);
 				if ((packet.has_ledgerprevious()) && (packet.ledgerprevious().size() == (256 / 8)))
+				{
 					memcpy(mPreviousLedgerHash.begin(), packet.ledgerprevious().data(), 256 / 8);
+					addLedger(mPreviousLedgerHash);
+				}
 				else mPreviousLedgerHash.zero();
 			}
 
@@ -915,6 +918,7 @@ void Peer::recvStatus(newcoin::TMStatusChange& packet)
 	if (packet.has_ledgerhash() && (packet.ledgerhash().size() == (256 / 8)))
 	{ // a peer has changed ledgers
 		memcpy(mClosedLedgerHash.begin(), packet.ledgerhash().data(), 256 / 8);
+		addLedger(mClosedLedgerHash);
 		Log(lsTRACE) << "peer LCL is " << mClosedLedgerHash << " " << getIP();
 	}
 	else
@@ -926,6 +930,7 @@ void Peer::recvStatus(newcoin::TMStatusChange& packet)
 	if (packet.has_ledgerhashprevious() && packet.ledgerhashprevious().size() == (256 / 8))
 	{
 		memcpy(mPreviousLedgerHash.begin(), packet.ledgerhashprevious().data(), 256 / 8);
+		addLedger(mPreviousLedgerHash);
 	}
 	else mPreviousLedgerHash.zero();
 }
@@ -1134,7 +1139,20 @@ void Peer::recvLedger(newcoin::TMLedgerData& packet)
 
 bool Peer::hasLedger(const uint256& hash) const
 {
-	return (hash == mClosedLedgerHash) || (hash == mPreviousLedgerHash);
+	BOOST_FOREACH(const uint256& ledger, mRecentLedgers)
+		if (ledger == hash)
+			return true;
+	return false;
+}
+
+void Peer::addLedger(const uint256& hash)
+{
+	BOOST_FOREACH(const uint256& ledger, mRecentLedgers)
+		if (ledger == hash)
+			return;
+	if (mRecentLedgers.size() == 16)
+		mRecentLedgers.pop_front();
+	mRecentLedgers.push_back(hash);
 }
 
 // Get session information we can sign to prevent man in the middle attack.
diff --git a/src/Peer.h b/src/Peer.h
index 13c5fdb2de..ae4abf7307 100644
--- a/src/Peer.h
+++ b/src/Peer.h
@@ -44,7 +44,8 @@ private:
 	ipPort			mIpPortConnect;
 	uint256			mCookieHash;
 
-	uint256						mClosedLedgerHash, mPreviousLedgerHash;
+	uint256			mClosedLedgerHash, mPreviousLedgerHash;
+	std::list<uint256>	mRecentLedgers;
 
 	boost::asio::ssl::stream<boost::asio::ip::tcp::socket>		mSocketSsl;
 
@@ -116,6 +117,8 @@ protected:
 
 	void getSessionCookie(std::string& strDst);
 
+	void addLedger(const uint256& ledger);
+
 public:
 
 	//bool operator == (const Peer& other);