From 93ff88bcb8512a1273f5382282b5c2229f226b81 Mon Sep 17 00:00:00 2001
From: orignal <romakoshelkin@yandex.ru>
Date: Fri, 4 Apr 2014 16:29:40 -0400
Subject: [PATCH] DH keys supplier

---
 Transports.cpp | 75 ++++++++++++++++++++++++++++++++++++++++++++++----
 Transports.h   | 31 +++++++++++++++++++++
 2 files changed, 101 insertions(+), 5 deletions(-)

diff --git a/Transports.cpp b/Transports.cpp
index 48462ae3..6c326e72 100644
--- a/Transports.cpp
+++ b/Transports.cpp
@@ -9,10 +9,76 @@ using namespace i2p::data;
 
 namespace i2p
 {
+	DHKeysPairSupplier::~DHKeysPairSupplier ()
+	{
+		Stop ();
+	}
+
+	void DHKeysPairSupplier::Start ()
+	{
+		m_IsRunning = true;
+		m_Thread = new std::thread (std::bind (&DHKeysPairSupplier::Run, this));
+	}
+
+	void DHKeysPairSupplier::Stop ()
+	{
+		m_IsRunning = false;
+		m_Acquired.notify_one ();	
+		if (m_Thread)
+		{	
+			m_Thread->join (); 
+			delete m_Thread;
+			m_Thread = 0;
+		}	
+	}
+
+	void DHKeysPairSupplier::Run ()
+	{
+		while (m_IsRunning)
+		{
+			int num;
+			while ((num = m_QueueSize - m_Queue.size ()) > 0)
+				CreateDHKeysPairs (num);
+			std::unique_lock<std::mutex>  l(m_AcquiredMutex);
+			m_Acquired.wait (l); // wait for element gets aquired
+		}
+	}		
+
+	void DHKeysPairSupplier::CreateDHKeysPairs (int num)
+	{
+		if (num > 0)
+		{
+			for (int i = 0; i < num; i++)
+			{
+				i2p::data::DHKeysPair * pair = new i2p::data::DHKeysPair ();
+				i2p::data::CreateRandomDHKeysPair (pair);
+				m_Queue.push (pair);
+			}
+		}
+	}
+
+	i2p::data::DHKeysPair * DHKeysPairSupplier::Acquire ()
+	{
+		if (!m_Queue.empty ())
+		{
+			auto pair = m_Queue.front ();
+			m_Queue.pop ();
+			m_Acquired.notify_one ();
+			return pair;
+		}	
+		else // queue is empty, create new
+		{
+			i2p::data::DHKeysPair * pair = new i2p::data::DHKeysPair ();
+			i2p::data::CreateRandomDHKeysPair (pair);
+			return pair;
+		}
+	}
+
 	Transports transports;	
 	
 	Transports::Transports (): 
-		m_Thread (nullptr), m_Work (m_Service),m_NTCPAcceptor (nullptr), m_SSUServer (nullptr)
+		m_Thread (nullptr), m_Work (m_Service), m_NTCPAcceptor (nullptr), 
+		m_SSUServer (nullptr), m_DHKeysPairSupplier (5) // 5 pre-generated keys
 	{		
 	}
 		
@@ -23,6 +89,7 @@ namespace i2p
 
 	void Transports::Start ()
 	{
+		m_DHKeysPairSupplier.Start ();
 		m_IsRunning = true;
 		m_Thread = new std::thread (std::bind (&Transports::Run, this));
 		m_Timer = new boost::asio::deadline_timer (m_Service);
@@ -74,6 +141,7 @@ namespace i2p
 			delete m_SSUServer;
 		}
 
+		m_DHKeysPairSupplier.Stop ();
 		m_IsRunning = false;
 		m_Service.stop ();
 		if (m_Thread)
@@ -223,9 +291,6 @@ namespace i2p
 		
 	i2p::data::DHKeysPair * Transports::GetNextDHKeysPair ()
 	{
-		// TODO: use supplier with separate thread
-		i2p::data::DHKeysPair * pair = new i2p::data::DHKeysPair ();
-		i2p::data::CreateRandomDHKeysPair (pair);
-		return pair;
+		return m_DHKeysPairSupplier.Acquire ();
 	}
 }
diff --git a/Transports.h b/Transports.h
index ed75cd60..bcec7690 100644
--- a/Transports.h
+++ b/Transports.h
@@ -2,8 +2,11 @@
 #define TRANSPORTS_H__
 
 #include <thread>
+#include <mutex>
+#include <condition_variable>
 #include <functional>
 #include <map>
+#include <queue>
 #include <string>
 #include <boost/asio.hpp>
 #include "NTCPSession.h"
@@ -14,6 +17,32 @@
 
 namespace i2p
 {
+	class DHKeysPairSupplier
+	{
+		public:
+
+			DHKeysPairSupplier (int size): m_QueueSize (size), m_IsRunning (false), m_Thread (nullptr) {};
+			~DHKeysPairSupplier ();
+			void Start ();
+			void Stop ();
+			i2p::data::DHKeysPair * Acquire ();
+
+		private:
+
+			void Run ();
+			void CreateDHKeysPairs (int num);
+
+		private:
+
+			int m_QueueSize;
+			std::queue<i2p::data::DHKeysPair *> m_Queue;
+
+			bool m_IsRunning;
+			std::thread * m_Thread;	
+			std::condition_variable m_Acquired;
+			std::mutex m_AcquiredMutex;
+	};
+
 	class Transports
 	{
 		public:
@@ -56,6 +85,8 @@ namespace i2p
 			i2p::ssu::SSUServer * m_SSUServer;
 			boost::asio::deadline_timer * m_Timer;
 
+			DHKeysPairSupplier m_DHKeysPairSupplier;
+
 		public:
 
 			// for HTTP only