From 3d38bcbe8add00b558012fa0cd4e0be26464dbeb Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sun, 3 Oct 2010 18:31:48 +0000
Subject: [PATCH] Use RAII for setting the anti-recursion flags Fix some
 crashes with empty cur_blocks Refuse to give up the last of cur_blocks

---
 source/libmarklin/train.cpp | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/source/libmarklin/train.cpp b/source/libmarklin/train.cpp
index 96566a6..8166c09 100644
--- a/source/libmarklin/train.cpp
+++ b/source/libmarklin/train.cpp
@@ -24,6 +24,19 @@ Distributed under the GPL
 using namespace std;
 using namespace Msp;
 
+namespace {
+
+struct SetFlag
+{
+	bool &flag;
+
+	SetFlag(bool &f): flag(f) { flag = true; }
+	~SetFlag() { flag = false; }
+};
+
+}
+
+
 namespace Marklin {
 
 Train::Train(Layout &l, const VehicleType &t, unsigned a):
@@ -202,7 +215,7 @@ void Train::set_route(const Route *r)
 	next_route = 0;
 	end_of_route = false;
 
-	if(route)
+	if(route && !cur_blocks.empty())
 	{
 		BlockRef &last = (rsv_blocks.empty() ? cur_blocks.back() : rsv_blocks.back());
 		BlockRef next = last.next();
@@ -310,6 +323,9 @@ int Train::get_entry_to_block(Block &block) const
 
 float Train::get_reserved_distance() const
 {
+	if(cur_blocks.empty())
+		return 0;
+
 	Vehicle &veh = *(reverse ? vehicles.back() : vehicles.front());
 	const VehicleType &vtype = veh.get_type();
 
@@ -410,9 +426,8 @@ void Train::tick(const Time::TimeStamp &t, const Time::TimeDelta &dt)
 		float d = get_real_speed(current_speed)*(dt/Time::sec);
 		if(ok)
 		{
-			advancing = true;
+			SetFlag setf(advancing);
 			vehicle.advance(reverse ? -d : d);
-			advancing = false;
 		}
 		else if(accurate_position)
 		{
@@ -657,7 +672,7 @@ void Train::sensor_event(unsigned addr, bool state)
 				}
 			}
 		
-		if(end!=cur_blocks.begin())
+		if(end!=cur_blocks.begin() && end!=cur_blocks.end())
 			// Free blocks up to the last inactive sensor
 			release_blocks(cur_blocks, cur_blocks.begin(), end);
 	}
@@ -728,7 +743,7 @@ unsigned Train::reserve_more()
 		}
 	}
 
-	reserving = true;
+	SetFlag setf(reserving);
 
 	bool got_more = false;
 	BlockRef *good = last;
@@ -846,7 +861,6 @@ unsigned Train::reserve_more()
 			last = &rsv_blocks.back();
 	}
 
-	reserving = false;
 
 	// Make any sensorless blocks at the beginning immediately current
 	list<BlockRef>::iterator i;
-- 
2.45.2