From 67cd1b26d2833903e51b91e167a3d1f7ae884a31 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Wed, 11 Feb 2015 18:28:49 +0200
Subject: [PATCH] Better sequence syncing on route change

Immediately go into the wait state if an uncleared sequence point is
encountered during sync.
---
 source/libr2c2/trainrouter.cpp | 44 +++++++++++++++++++++-------------
 source/libr2c2/trainrouter.h   |  1 +
 2 files changed, 28 insertions(+), 17 deletions(-)

diff --git a/source/libr2c2/trainrouter.cpp b/source/libr2c2/trainrouter.cpp
index 27fca7a..e38e29c 100644
--- a/source/libr2c2/trainrouter.cpp
+++ b/source/libr2c2/trainrouter.cpp
@@ -85,8 +85,8 @@ void TrainRouter::route_changed()
 {
 	BlockIter fncb = train.get_first_noncritical_block();
 
+	arrival = ON_THE_WAY;
 	reserving_route = routes.begin();
-	bool already_at_end = false;
 	if(!routes.empty())
 	{
 		/* Find the route that should be used for the next allocated block.  We
@@ -98,7 +98,7 @@ void TrainRouter::route_changed()
 		{
 			if(!advance_to_track(reserving_route, track))
 			{
-				already_at_end = true;
+				arrival = RESERVED_TO_END;
 				break;
 			}
 			if(&track->get_block()==fncb.block())
@@ -106,30 +106,34 @@ void TrainRouter::route_changed()
 
 			if(seq_begin!=sequence_points.end() && seq_begin->block==&track->get_block())
 			{
+				// Assume any sequence points within critical blocks to be cleared
 				current_sequence = seq_begin->sequence_out;
 				++seq_begin;
 			}
 		}
 
 		sequence_points.erase(sequence_points.begin(), seq_begin);
-	}
 
-	if(!already_at_end)
-	{
-		// We are not at the end of the route now, but might have been before.
-		arrival = ON_THE_WAY;
-		train.refresh_blocks_from(*fncb);
-		if(!arrival)
-			train.stop_at(0);
+		if(!sequence_points.empty())
+		{
+			const SequencePoint &sp = sequence_points.front();
+			if(sp.block==fncb.block() && !sp.is_cleared())
+			{
+				arrival = WAITING_FOR_SEQUENCE;
+				sequence_check_pending = true;
+			}
+		}
 	}
-	else if(!arrival)
-	{
-		/* If arrival wasn't set before (perhaps because we weren't on a route),
-		set it now. */
-		arrival = RESERVED_TO_END;
+
+	/* Refresh from the first non-critical block to pick up any changes in the
+	route.  Set stop marker first in case an arrival condition was met within the
+	critical blocks. */
+	if(arrival)
 		train.stop_at(&*fncb.flip());
-		train.refresh_blocks_from(*fncb);
-	}
+	train.refresh_blocks_from(*fncb);
+	// If no arrival condition was found, clear a possible previous stop marker.
+	if(!arrival)
+		train.stop_at(0);
 
 	const Route *route = get_route();
 	signal_route_changed.emit(route);
@@ -241,7 +245,10 @@ void TrainRouter::tick(const Time::TimeDelta &dt)
 	if(sequence_check_pending)
 	{
 		if(sequence_points.front().is_cleared())
+		{
+			arrival = ON_THE_WAY;
 			train.stop_at(0);
+		}
 		sequence_check_pending = false;
 	}
 
@@ -345,7 +352,10 @@ void TrainRouter::block_reserved(Block &block, Train *t)
 	{
 		SequencePoint &sp = sequence_points.front();
 		if(sp.block==&track->get_block() && !sp.is_cleared())
+		{
+			arrival = WAITING_FOR_SEQUENCE;
 			train.stop_at(&block);
+		}
 	}
 }
 
diff --git a/source/libr2c2/trainrouter.h b/source/libr2c2/trainrouter.h
index 4571209..542d1ff 100644
--- a/source/libr2c2/trainrouter.h
+++ b/source/libr2c2/trainrouter.h
@@ -43,6 +43,7 @@ private:
 	enum ArrivalState
 	{
 		ON_THE_WAY,
+		WAITING_FOR_SEQUENCE,
 		RESERVED_TO_END,
 		ARRIVED
 	};
-- 
2.43.0