fixed potential deadlock

AddressBook.cpp

@@ -658,16 +658,23 @@ namespace client
 		if (!leaseSet)
 		{
 			std::unique_lock<std::mutex> l(newDataReceivedMutex);
-			i2p::client::context.GetSharedLocalDestination ()->RequestDestination (m_Ident,
+			if (i2p::client::context.GetSharedLocalDestination ()->RequestDestination (m_Ident,
 				[&newDataReceived, &leaseSet](std::shared_ptr<i2p::data::LeaseSet> ls)
 			    {
 					leaseSet = ls;
 					newDataReceived.notify_all ();
-				});
+				}))
+			{
 				if (newDataReceived.wait_for (l, std::chrono::seconds (SUBSCRIPTION_REQUEST_TIMEOUT)) == std::cv_status::timeout)
 				{
 					LogPrint (eLogError, "Addressbook: Subscription LeaseSet request timeout expired");
-				i2p::client::context.GetSharedLocalDestination ()->CancelDestinationRequest (m_Ident);
+					i2p::client::context.GetSharedLocalDestination ()->CancelDestinationRequest (m_Ident, false); // don't notify, because we know it already
+					return false;
+				}
+			}
+			else
+			{
+				LogPrint (eLogError, "Addressbook: Destination is not ready");
 				return false;
 			}
 		}

Destination.cpp

@@ -486,17 +486,17 @@ namespace client
 		return true;
 	}
 
-	void LeaseSetDestination::CancelDestinationRequest (const i2p::data::IdentHash& dest)
+	void LeaseSetDestination::CancelDestinationRequest (const i2p::data::IdentHash& dest, bool notify)
 	{
 		auto s = shared_from_this ();
-		m_Service.post ([dest, s](void)
+		m_Service.post ([dest, notify, s](void)
 			{
 				auto it = s->m_LeaseSetRequests.find (dest);
 				if (it != s->m_LeaseSetRequests.end ())
 				{	
 					auto requestComplete = it->second->requestComplete; 
 					s->m_LeaseSetRequests.erase (it);
-					if (requestComplete) requestComplete (nullptr);
+					if (notify && requestComplete) requestComplete (nullptr);
 				}	
 			});				
 	}

Destination.h

@@ -79,7 +79,7 @@ namespace client
 			bool IsReady () const { return m_LeaseSet && !m_LeaseSet->IsExpired () && m_Pool->GetOutboundTunnels ().size () > 0; };
 			std::shared_ptr<const i2p::data::LeaseSet> FindLeaseSet (const i2p::data::IdentHash& ident);
 			bool RequestDestination (const i2p::data::IdentHash& dest, RequestComplete requestComplete = nullptr);
-			void CancelDestinationRequest (const i2p::data::IdentHash& dest);	
+			void CancelDestinationRequest (const i2p::data::IdentHash& dest, bool notify = true);	
 
 			// implements GarlicDestination
 			std::shared_ptr<const i2p::data::LocalLeaseSet> GetLeaseSet ();