From d5075d706c2888169ade77770f72239ac08ad58c Mon Sep 17 00:00:00 2001
From: orignal <i2porignal@yandex.ru>
Date: Sun, 7 Aug 2016 16:27:36 -0400
Subject: [PATCH] eliminate decay timer

---
 SSUData.cpp | 30 ++++++++----------------------
 SSUData.h   | 10 ++++------
 2 files changed, 12 insertions(+), 28 deletions(-)

diff --git a/SSUData.cpp b/SSUData.cpp
index 2bd65682..e802791d 100644
--- a/SSUData.cpp
+++ b/SSUData.cpp
@@ -25,10 +25,10 @@ namespace transport
 	}
 
 	SSUData::SSUData (SSUSession& session):
-		m_Session (session), m_ResendTimer (session.GetService ()), m_DecayTimer (session.GetService ()),
+		m_Session (session), m_ResendTimer (session.GetService ()), 
 		m_IncompleteMessagesCleanupTimer (session.GetService ()), 
 		m_MaxPacketSize (session.IsV6 () ? SSU_V6_MAX_PACKET_SIZE : SSU_V4_MAX_PACKET_SIZE), 
-		m_PacketSize (m_MaxPacketSize)
+		m_PacketSize (m_MaxPacketSize), m_LastMessageReceivedTime (0)
 	{
 	}
 
@@ -44,7 +44,6 @@ namespace transport
 	void SSUData::Stop ()
 	{
 		m_ResendTimer.cancel ();
-		m_DecayTimer.cancel ();
 		m_IncompleteMessagesCleanupTimer.cancel ();
 	}	
 		
@@ -233,11 +232,8 @@ namespace transport
 				{
 					if (!m_ReceivedMessages.count (msgID))
 					{	
-						if (m_ReceivedMessages.size () > MAX_NUM_RECEIVED_MESSAGES)
-							m_ReceivedMessages.clear ();
-						else
-							ScheduleDecay ();
 						m_ReceivedMessages.insert (msgID);
+						m_LastMessageReceivedTime = i2p::util::GetSecondsSinceEpoch ();
 						if (!msg->IsExpired ())
 							m_Handler.PutNextMessage (msg);
 						else
@@ -469,21 +465,6 @@ namespace transport
 		}	
 	}	
 
-	void SSUData::ScheduleDecay ()
-	{		
-		m_DecayTimer.cancel ();
-		m_DecayTimer.expires_from_now (boost::posix_time::seconds(DECAY_INTERVAL));
-		auto s = m_Session.shared_from_this();
-		m_ResendTimer.async_wait ([s](const boost::system::error_code& ecode)
-			{ s->m_Data.HandleDecayTimer (ecode); });
-	}	
-
-	void SSUData::HandleDecayTimer (const boost::system::error_code& ecode)
-	{
-		if (ecode != boost::asio::error::operation_aborted)
-			m_ReceivedMessages.clear ();
-	}	
-
 	void SSUData::ScheduleIncompleteMessagesCleanup ()
 	{
 		m_IncompleteMessagesCleanupTimer.cancel ();
@@ -508,6 +489,11 @@ namespace transport
 				else
 					it++;
 			}	
+			// decay
+			if (m_ReceivedMessages.size () > MAX_NUM_RECEIVED_MESSAGES ||
+			    i2p::util::GetSecondsSinceEpoch () > m_LastMessageReceivedTime + DECAY_INTERVAL)
+				m_ReceivedMessages.clear ();
+			
 			ScheduleIncompleteMessagesCleanup ();
 		}	
 	}	
diff --git a/SSUData.h b/SSUData.h
index bfc75128..f3ad9ea8 100644
--- a/SSUData.h
+++ b/SSUData.h
@@ -5,7 +5,7 @@
 #include <string.h>
 #include <map>
 #include <vector>
-#include <set>
+#include <unordered_set>
 #include <memory>
 #include <boost/asio.hpp>
 #include "I2NPProtocol.h"
@@ -109,9 +109,6 @@ namespace transport
 			void ScheduleResend ();
 			void HandleResendTimer (const boost::system::error_code& ecode);	
 
-			void ScheduleDecay ();
-			void HandleDecayTimer (const boost::system::error_code& ecode);	
-
 			void ScheduleIncompleteMessagesCleanup ();
 			void HandleIncompleteMessagesCleanupTimer (const boost::system::error_code& ecode);	
 			
@@ -121,10 +118,11 @@ namespace transport
 			SSUSession& m_Session;
 			std::map<uint32_t, std::unique_ptr<IncompleteMessage> > m_IncompleteMessages;
 			std::map<uint32_t, std::unique_ptr<SentMessage> > m_SentMessages;
-			std::set<uint32_t> m_ReceivedMessages;
-			boost::asio::deadline_timer m_ResendTimer, m_DecayTimer, m_IncompleteMessagesCleanupTimer;
+			std::unordered_set<uint32_t> m_ReceivedMessages;
+			boost::asio::deadline_timer m_ResendTimer, m_IncompleteMessagesCleanupTimer;
 			int m_MaxPacketSize, m_PacketSize;
 			i2p::I2NPMessagesHandler m_Handler;
+			uint32_t m_LastMessageReceivedTime; // in second
 	};	
 }
 }