From 49b46b85dc301bfe1f311fcbde4563baa03416b7 Mon Sep 17 00:00:00 2001
From: Fletcher Dunn <fletcherd@valvesoftware.com>
Date: Wed, 13 Feb 2019 10:16:14 -0800
Subject: [PATCH] Fix bug not initializing data structures early enough.

We were initialzing some sentinels and iterators when a connection was established.  But these variables are accessed when you just query the state of the connection, which might happen before then.
---
 .../clientlib/steamnetworkingsockets_snp.cpp  | 50 ++++++++++---------
 .../clientlib/steamnetworkingsockets_snp.h    |  3 ++
 2 files changed, 30 insertions(+), 23 deletions(-)

diff --git a/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_snp.cpp b/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_snp.cpp
index 1b47f91..e8981dd 100644
--- a/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_snp.cpp
+++ b/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_snp.cpp
@@ -198,34 +198,38 @@ void SSNPSenderState::RemoveAckedReliableMessageFromUnackedList()
 	}
 }
 
+//-----------------------------------------------------------------------------
+SSNPSenderState::SSNPSenderState()
+{
+	// Setup the table of inflight packets with a sentinel.
+	m_mapInFlightPacketsByPktNum.clear();
+	SNPInFlightPacket_t &sentinel = m_mapInFlightPacketsByPktNum[INT64_MIN];
+	sentinel.m_bNack = false;
+	sentinel.m_usecWhenSent = 0;
+	m_itNextInFlightPacketToTimeout = m_mapInFlightPacketsByPktNum.end();
+}
+
+//-----------------------------------------------------------------------------
+SSNPReceiverState::SSNPReceiverState()
+{
+	// Init packet gaps with a sentinel
+	m_mapPacketGaps.clear();
+	SSNPPacketGap &sentinel = m_mapPacketGaps[INT64_MAX];
+	sentinel.m_nEnd = INT64_MAX; // Fixed value
+	sentinel.m_usecWhenOKToNack = INT64_MAX; // Fixed value, for when there is nothing left to nack
+	sentinel.m_usecWhenAckPrior = INT64_MAX; // Time when we need to flush a report on all lower-numbered packets
+
+	// Point at the sentinel
+	m_itPendingAck = m_mapPacketGaps.end();
+	--m_itPendingAck;
+	m_itPendingNack = m_itPendingAck;
+}
+
 //-----------------------------------------------------------------------------
 void CSteamNetworkConnectionBase::SNP_InitializeConnection( SteamNetworkingMicroseconds usecNow )
 {
 	m_senderState.TokenBucket_Init( usecNow );
 
-	// Setup the table of inflight packets with a sentinel.
-	{
-		m_senderState.m_mapInFlightPacketsByPktNum.clear();
-		SNPInFlightPacket_t &sentinel = m_senderState.m_mapInFlightPacketsByPktNum[INT64_MIN];
-		sentinel.m_bNack = false;
-		sentinel.m_usecWhenSent = 0;
-		m_senderState.m_itNextInFlightPacketToTimeout = m_senderState.m_mapInFlightPacketsByPktNum.end();
-	}
-
-	// Init packet gaps with a sentinel
-	{
-		m_receiverState.m_mapPacketGaps.clear();
-		SSNPPacketGap &sentinel = m_receiverState.m_mapPacketGaps[INT64_MAX];
-		sentinel.m_nEnd = INT64_MAX; // Fixed value
-		sentinel.m_usecWhenOKToNack = INT64_MAX; // Fixed value, for when there is nothing left to nack
-		sentinel.m_usecWhenAckPrior = INT64_MAX; // Time when we need to flush a report on all lower-numbered packets
-
-		// Point at the sentinel
-		m_receiverState.m_itPendingAck = m_receiverState.m_mapPacketGaps.end();
-		--m_receiverState.m_itPendingAck;
-		m_receiverState.m_itPendingNack = m_receiverState.m_itPendingAck;
-	}
-
 	SteamNetworkingMicroseconds usecPing = GetUsecPingWithFallback( this );
 
 	/*
diff --git a/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_snp.h b/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_snp.h
index 008d29a..e50801d 100644
--- a/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_snp.h
+++ b/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_snp.h
@@ -170,6 +170,7 @@ struct SSNPSendMessageList
 
 struct SSNPSenderState
 {
+	SSNPSenderState();
 	~SSNPSenderState() {
 		Reset();
 	}
@@ -350,6 +351,8 @@ struct SSNPPacketGap
 
 struct SSNPReceiverState
 {
+	SSNPReceiverState();
+
 	/// Unreliable message segments that we have received.  When an unreliable message
 	/// needs to be fragmented, we store the pieces here.  NOTE: it might be more efficient
 	/// to use a simpler container, with worse O(), since this should ordinarily be