From a53308f7e84d468a7484d2b1e7643865cfee0383 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Fri, 23 Dec 2011 17:34:07 +0000
Subject: [PATCH] Gunnar Holm, "After upgrading from 2.8.3 to 3.0.1 we
 experienced a lock in the Mutex functionality when using
 Terrain::setVerticalScale. This was caused by the following call sequence
 resulting in a lockup:

void Terrain::setVerticalScale(float scale)
  CALLS    dirtyRegisteredTiles();


void Terrain::dirtyRegisteredTiles(int dirtyMask)
 SETS LOCK    OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_mutex);
 and CALLS (on every tile)   setDirtyMask(dirtyMask);


void TerrainTile::setDirtyMask(int dirtyMask)
 CALLS _terrain->updateTerrainTileOnNextFrame(this);


void Terrain::updateTerrainTileOnNextFrame(TerrainTile* terrainTile)
 SETS LOCK   OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_mutex);
******* PROBLEM - since lock has already been set! ********


The suggested fix submitted changes from using Mutex to ReentrantMutex.
"
---
 include/osgTerrain/Terrain |  3 ++-
 src/osgTerrain/Terrain.cpp | 17 ++++++++---------
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/include/osgTerrain/Terrain b/include/osgTerrain/Terrain
index 062bcf829..c7b3275ea 100644
--- a/include/osgTerrain/Terrain
+++ b/include/osgTerrain/Terrain
@@ -15,6 +15,7 @@
 #define OSGTerrain 1
 
 #include <osg/CoordinateSystemNode>
+#include <OpenThreads/ReentrantMutex>
 
 #include <osgTerrain/TerrainTile>
 
@@ -109,7 +110,7 @@ class OSGTERRAIN_EXPORT Terrain : public osg::CoordinateSystemNode
         TerrainTile::BlendingPolicy         _blendingPolicy;
         bool                                _equalizeBoundaries;
 
-        mutable OpenThreads::Mutex          _mutex;
+        mutable OpenThreads::ReentrantMutex _mutex;
         TerrainTileSet                      _terrainTileSet;
         TerrainTileMap                      _terrainTileMap;
         TerrainTileSet                      _updateTerrainTileSet;
diff --git a/src/osgTerrain/Terrain.cpp b/src/osgTerrain/Terrain.cpp
index 8d153ee94..ee84c0f8d 100644
--- a/src/osgTerrain/Terrain.cpp
+++ b/src/osgTerrain/Terrain.cpp
@@ -44,7 +44,7 @@ Terrain::Terrain(const Terrain& ts, const osg::CopyOp& copyop):
 
 Terrain::~Terrain()
 {
-    OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_mutex);
+    OpenThreads::ScopedLock<OpenThreads::ReentrantMutex> lock(_mutex);
 
     for(TerrainTileSet::iterator itr = _terrainTileSet.begin();
         itr != _terrainTileSet.end();
@@ -96,7 +96,7 @@ void Terrain::traverse(osg::NodeVisitor& nv)
             typedef std::list< osg::ref_ptr<TerrainTile> >  TerrainTileList;
             TerrainTileList tiles;
             {
-                OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_mutex);
+                OpenThreads::ScopedLock<OpenThreads::ReentrantMutex> lock(_mutex);
                 std::copy(_updateTerrainTileSet.begin(), _updateTerrainTileSet.end(), std::back_inserter(tiles));
                 _updateTerrainTileSet.clear();
             }
@@ -116,14 +116,14 @@ void Terrain::traverse(osg::NodeVisitor& nv)
 
 void Terrain::updateTerrainTileOnNextFrame(TerrainTile* terrainTile)
 {
-    OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_mutex);
+    OpenThreads::ScopedLock<OpenThreads::ReentrantMutex> lock(_mutex);
     _updateTerrainTileSet.insert(terrainTile);
 }
 
 
 TerrainTile* Terrain::getTile(const TileID& tileID)
 {
-    OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_mutex);
+    OpenThreads::ScopedLock<OpenThreads::ReentrantMutex> lock(_mutex);
 
     // OSG_NOTICE<<"Terrain::getTile("<<tileID.level<<", "<<tileID.x<<", "<<tileID.y<<")"<<std::endl;
 
@@ -135,7 +135,7 @@ TerrainTile* Terrain::getTile(const TileID& tileID)
 
 const TerrainTile* Terrain::getTile(const TileID& tileID) const
 {
-    OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_mutex);
+    OpenThreads::ScopedLock<OpenThreads::ReentrantMutex> lock(_mutex);
 
     TerrainTileMap::const_iterator itr = _terrainTileMap.find(tileID);
     if (itr == _terrainTileMap.end()) return 0;
@@ -145,8 +145,7 @@ const TerrainTile* Terrain::getTile(const TileID& tileID) const
 
 void Terrain::dirtyRegisteredTiles(int dirtyMask)
 {
-    OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_mutex);
-
+    OpenThreads::ScopedLock<OpenThreads::ReentrantMutex> lock(_mutex);
     for(TerrainTileSet::iterator itr = _terrainTileSet.begin();
         itr != _terrainTileSet.end();
         ++itr)
@@ -160,7 +159,7 @@ void Terrain::registerTerrainTile(TerrainTile* tile)
 {
     if (!tile) return;
 
-    OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_mutex);
+    OpenThreads::ScopedLock<OpenThreads::ReentrantMutex> lock(_mutex);
 
     if (tile->getTileID().valid())
     {
@@ -179,7 +178,7 @@ void Terrain::unregisterTerrainTile(TerrainTile* tile)
 {
     if (!tile) return;
 
-    OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_mutex);
+    OpenThreads::ScopedLock<OpenThreads::ReentrantMutex> lock(_mutex);
 
     if (tile->getTileID().valid())
     {