From 6d1944b9e2f629b79248a451930f5a987398f61b Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Thu, 20 Jan 2011 12:32:20 +0000
Subject: [PATCH] From Matthew Johnson-Roberson, "Small fix for operation
 thread to protect the access to _operations vector by functions
 getNumOperationsInQueue() and empty(). It is simply an addition of  
 OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_operationsMutex); to
 protect against accessing while writing which was segfaulting in VPB
 specifically in void ThreadPool::run(osg::Operation* op) in the waiting loop

while (_operationQueue->getNumOperationsInQueue() >= _maxNumberOfOperationsInQueue)
"
---
 include/osg/OperationThread |  4 ++--
 src/osg/OperationThread.cpp | 13 +++++++++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/include/osg/OperationThread b/include/osg/OperationThread
index e3fda41f7..6d3ef2c6e 100644
--- a/include/osg/OperationThread
+++ b/include/osg/OperationThread
@@ -105,10 +105,10 @@ class OSG_EXPORT OperationQueue : public Referenced
         osg::ref_ptr<Operation> getNextOperation(bool blockIfEmpty = false);
 
         /** Return true if the operation queue is empty. */
-        bool empty() const { return _operations.empty(); }
+        bool empty();
         
         /** Return the num of pending operations that are sitting in the OperationQueue.*/
-        unsigned int getNumOperationsInQueue() const { return static_cast<unsigned int>(_operations.size()); }
+        unsigned int getNumOperationsInQueue();
 
         /** Add operation to end of OperationQueue, this will be 
           * executed by the operation thread once this operation gets to the head of the queue.*/
diff --git a/src/osg/OperationThread.cpp b/src/osg/OperationThread.cpp
index 98276a1d6..5835928d9 100644
--- a/src/osg/OperationThread.cpp
+++ b/src/osg/OperationThread.cpp
@@ -55,6 +55,19 @@ OperationQueue::~OperationQueue()
 {
 }
 
+bool OperationQueue::empty() 
+{ 
+
+  OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_operationsMutex);
+  return _operations.empty(); 
+}
+
+unsigned int OperationQueue::getNumOperationsInQueue()
+{
+  OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_operationsMutex);
+  return static_cast<unsigned int>(_operations.size()); 
+}
+
 ref_ptr<Operation> OperationQueue::getNextOperation(bool blockIfEmpty)
 {
     if (blockIfEmpty && _operations.empty())