From effc7049a235ec2c878a5a41cb4c72f00f66b33b Mon Sep 17 00:00:00 2001
From: hikerstk <hikerstk@178a84e3-b1eb-0310-8ba1-8eac791a3b58>
Date: Thu, 24 Oct 2013 06:04:22 +0000
Subject: [PATCH] Avoid infinite recursion when a track with looped shortcuts
 is loaded.

git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@14300 178a84e3-b1eb-0310-8ba1-8eac791a3b58
---
 src/tracks/quad_graph.cpp | 19 ++++++++++++++++---
 src/tracks/quad_graph.hpp |  4 +++-
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/src/tracks/quad_graph.cpp b/src/tracks/quad_graph.cpp
index 4c1e0dd31..d85b87c01 100644
--- a/src/tracks/quad_graph.cpp
+++ b/src/tracks/quad_graph.cpp
@@ -605,7 +605,7 @@ void QuadGraph::computeDistanceFromStart(unsigned int node, float new_distance)
         if(current_distance<new_distance)
         {
             float delta = new_distance - current_distance;
-            updateDistancesForAllSuccessors(gn->getQuadIndex(), delta);
+            updateDistancesForAllSuccessors(gn->getQuadIndex(), delta, 0);
         }
         return;
     }
@@ -634,9 +634,21 @@ void QuadGraph::computeDistanceFromStart(unsigned int node, float new_distance)
  *  distance from start.
  *  \param indx Index of the node for which to increase the distance.
  *  \param delta Amount by which to increase the distance.
+ *  \param recursive_count Counts how often this function was called 
+ *         recursively in order to catch incorrect graphs that contain loops.
  */
-void QuadGraph::updateDistancesForAllSuccessors(unsigned int indx, float delta)
+void QuadGraph::updateDistancesForAllSuccessors(unsigned int indx, float delta,
+                                                 unsigned int recursive_count)
 {
+    if(recursive_count>getNumNodes())
+    {
+        Log::error("QuadGraph",
+                   "Quad graph contains a loop (without start node).");
+        Log::fatal("QuadGraph",
+                   "Fix graph, check for directions of all shortcuts etc.");
+    }
+    recursive_count++;
+
     GraphNode &g=getNode(indx);
     g.setDistanceFromStart(g.getDistanceFromStart()+delta);
     for(unsigned int i=0; i<g.getNumberOfSuccessors(); i++)
@@ -653,7 +665,8 @@ void QuadGraph::updateDistancesForAllSuccessors(unsigned int indx, float delta)
         if(g.getDistanceFromStart()+g.getDistanceToSuccessor(i) >
             g_next.getDistanceFromStart())
         {
-            updateDistancesForAllSuccessors(g.getSuccessor(i), delta);
+            updateDistancesForAllSuccessors(g.getSuccessor(i), delta, 
+                                            recursive_count);
         }
     }
 }   // updateDistancesForAllSuccessors
diff --git a/src/tracks/quad_graph.hpp b/src/tracks/quad_graph.hpp
index 7c8d5d805..228bbbf76 100644
--- a/src/tracks/quad_graph.hpp
+++ b/src/tracks/quad_graph.hpp
@@ -123,7 +123,9 @@ public:
                                  const video::SColor &fill_color
                                         =video::SColor(127, 255, 255, 255) );
     void         mapPoint2MiniMap(const Vec3 &xyz, Vec3 *out) const;
-    void         updateDistancesForAllSuccessors(unsigned int indx, float delta);
+    void         updateDistancesForAllSuccessors(unsigned int indx, 
+                                                 float delta,
+                                                 unsigned int count);
     void         setupPaths();
     void         computeChecklineRequirements();
 // ----------------------------------------------------------------------