From 4ea8e7de5d29ed1747540c6058f2ee5bad63db43 Mon Sep 17 00:00:00 2001
From: Andrzej Kapolka <drzej.k@gmail.com>
Date: Wed, 23 Jul 2014 11:45:20 -0700
Subject: [PATCH] Atomics for better thread safety.

---
 libraries/metavoxels/src/MetavoxelData.cpp | 2 +-
 libraries/metavoxels/src/MetavoxelData.h   | 4 ++--
 libraries/metavoxels/src/SharedObject.cpp  | 4 ++--
 libraries/metavoxels/src/SharedObject.h    | 2 +-
 4 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/libraries/metavoxels/src/MetavoxelData.cpp b/libraries/metavoxels/src/MetavoxelData.cpp
index 112012e37f..0f8773a896 100644
--- a/libraries/metavoxels/src/MetavoxelData.cpp
+++ b/libraries/metavoxels/src/MetavoxelData.cpp
@@ -1117,7 +1117,7 @@ void MetavoxelNode::writeSpannerSubdivision(MetavoxelStreamState& state) const {
 }
 
 void MetavoxelNode::decrementReferenceCount(const AttributePointer& attribute) {
-    if (--_referenceCount == 0) {
+    if (!_referenceCount.deref()) {
         destroy(attribute);
         delete this;
     }
diff --git a/libraries/metavoxels/src/MetavoxelData.h b/libraries/metavoxels/src/MetavoxelData.h
index 1944090a38..dfebbe4586 100644
--- a/libraries/metavoxels/src/MetavoxelData.h
+++ b/libraries/metavoxels/src/MetavoxelData.h
@@ -212,7 +212,7 @@ public:
     void writeSpannerSubdivision(MetavoxelStreamState& state) const;
 
     /// Increments the node's reference count.
-    void incrementReferenceCount() { _referenceCount++; }
+    void incrementReferenceCount() { _referenceCount.ref(); }
 
     /// Decrements the node's reference count.  If the resulting reference count is zero, destroys the node
     /// and calls delete this.
@@ -238,7 +238,7 @@ private:
     
     friend class MetavoxelVisitation;
     
-    int _referenceCount;
+    QAtomicInt _referenceCount;
     void* _attributeValue;
     MetavoxelNode* _children[CHILD_COUNT];
 };
diff --git a/libraries/metavoxels/src/SharedObject.cpp b/libraries/metavoxels/src/SharedObject.cpp
index efc6aa4be6..053ef57bad 100644
--- a/libraries/metavoxels/src/SharedObject.cpp
+++ b/libraries/metavoxels/src/SharedObject.cpp
@@ -23,7 +23,7 @@
 REGISTER_META_OBJECT(SharedObject)
 
 SharedObject::SharedObject() :
-    _id(++_lastID),
+    _id(_nextID.fetchAndAddOrdered(1)),
     _originID(_id),
     _remoteID(0),
     _remoteOriginID(0) {
@@ -131,7 +131,7 @@ void SharedObject::dump(QDebug debug) const {
     }
 }
 
-int SharedObject::_lastID = 0;
+QAtomicInt SharedObject::_nextID(1);
 WeakSharedObjectHash SharedObject::_weakHash;
 QReadWriteLock SharedObject::_weakHashLock;
 
diff --git a/libraries/metavoxels/src/SharedObject.h b/libraries/metavoxels/src/SharedObject.h
index 5ff5aa9680..407fc820c8 100644
--- a/libraries/metavoxels/src/SharedObject.h
+++ b/libraries/metavoxels/src/SharedObject.h
@@ -87,7 +87,7 @@ private:
     int _remoteOriginID;
     QAtomicInt _referenceCount;
     
-    static int _lastID;
+    static QAtomicInt _nextID;
     static WeakSharedObjectHash _weakHash;
     static QReadWriteLock _weakHashLock;
 };