From 3b65b028b260fa11988297bb4248076a3b4fea8b Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Thu, 9 Oct 2003 09:48:36 +0000
Subject: [PATCH] Added protection to the DatabasePager::requestNodeFile()'s
 call to startThread to ensure that only one startThread is every issued.

---
 src/osgDB/DatabasePager.cpp | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/src/osgDB/DatabasePager.cpp b/src/osgDB/DatabasePager.cpp
index 2f4eb7c94..4b1067fe8 100644
--- a/src/osgDB/DatabasePager.cpp
+++ b/src/osgDB/DatabasePager.cpp
@@ -5,6 +5,8 @@
 #include <osg/Texture>
 #include <osg/Notify>
 
+#include <OpenThreads/ScopedLock>
+
 #ifdef WIN32
 #include <windows.h>
 #else
@@ -111,12 +113,22 @@ void DatabasePager::requestNodeFile(const std::string& fileName,osg::Group* grou
         _fileRequestListMutex.unlock();
     }
     
-    //if (!threadIsRunning())
     if (!isRunning())
     {
-        osg::notify(osg::DEBUG_INFO)<<"DatabasePager::startThread()"<<std::endl;
-        setSchedulePriority(PRIORITY_MIN);
-        startThread();
+        static OpenThreads::Mutex s_mutex;
+                
+        OpenThreads::ScopedLock<OpenThreads::Mutex> lock(s_mutex);
+        
+        static bool s_startThreadCalled = false;
+        
+        if (!s_startThreadCalled)
+        {
+            s_startThreadCalled = true;
+            osg::notify(osg::DEBUG_INFO)<<"DatabasePager::startThread()"<<std::endl;
+            setSchedulePriority(PRIORITY_MIN);
+            startThread();
+        }
+                
     }
 }