From 6817c9682e5483eb4aff765f054f8ecf956eb972 Mon Sep 17 00:00:00 2001
From: barnold1953 <brb555@utk.edu>
Date: Fri, 23 May 2014 11:17:55 -0700
Subject: [PATCH] Added a new lock specific to deleting, and improved safety

---
 interface/src/ui/overlays/Overlays.cpp | 43 ++++++++++++++++----------
 interface/src/ui/overlays/Overlays.h   |  1 +
 2 files changed, 28 insertions(+), 16 deletions(-)

diff --git a/interface/src/ui/overlays/Overlays.cpp b/interface/src/ui/overlays/Overlays.cpp
index bcac86d7f1..da7b05ead7 100644
--- a/interface/src/ui/overlays/Overlays.cpp
+++ b/interface/src/ui/overlays/Overlays.cpp
@@ -39,15 +39,22 @@ void Overlays::init(QGLWidget* parent) {
 }
 
 void Overlays::update(float deltatime) {
-    QWriteLocker lock(&_lock);
-    foreach (Overlay* thisOverlay, _overlays2D) {
-        thisOverlay->update(deltatime);
+
+    {
+        QWriteLocker lock(&_lock);
+        foreach(Overlay* thisOverlay, _overlays2D) {
+            thisOverlay->update(deltatime);
+        }
+        foreach(Overlay* thisOverlay, _overlays3D) {
+            thisOverlay->update(deltatime);
+        }
     }
-    foreach (Overlay* thisOverlay, _overlays3D) {
-        thisOverlay->update(deltatime);
-    }
-    while (!_overlaysToDelete.isEmpty()) {
-        delete _overlaysToDelete.takeLast();
+
+    if (!_overlaysToDelete.isEmpty()) {
+        QWriteLocker lock(&_deleteLock);
+        do {
+            delete _overlaysToDelete.takeLast();
+        } while (!_overlaysToDelete.isEmpty());
     }
     
 }
@@ -172,15 +179,19 @@ bool Overlays::editOverlay(unsigned int id, const QScriptValue& properties) {
 
 void Overlays::deleteOverlay(unsigned int id) {
     Overlay* overlayToDelete;
-    QWriteLocker lock(&_lock);
-    if (_overlays2D.contains(id)) {
-        overlayToDelete = _overlays2D.take(id);
-    } else if (_overlays3D.contains(id)) {
-        overlayToDelete = _overlays3D.take(id);
-    } else {
-        return;
+
+    {
+        QWriteLocker lock(&_lock);
+        if (_overlays2D.contains(id)) {
+            overlayToDelete = _overlays2D.take(id);
+        } else if (_overlays3D.contains(id)) {
+            overlayToDelete = _overlays3D.take(id);
+        } else {
+            return;
+        }
     }
-    
+
+    QWriteLocker lock(&_deleteLock);
     _overlaysToDelete.push_back(overlayToDelete);
 }
 
diff --git a/interface/src/ui/overlays/Overlays.h b/interface/src/ui/overlays/Overlays.h
index 20015b8af9..2fbdb993f4 100644
--- a/interface/src/ui/overlays/Overlays.h
+++ b/interface/src/ui/overlays/Overlays.h
@@ -46,6 +46,7 @@ private:
     unsigned int _nextOverlayID;
     QGLWidget* _parent;
     QReadWriteLock _lock;
+    QReadWriteLock _deleteLock;
 };