Crash/Deadlock fix: Web3DOverlay could be destroyed on wrong thread.

When script calls Entities.getChildrenIDs*() it is possible to deadlock the main thread, and also invoke
the destructor of Entities and Overlays, which is very NOT thread safe.

The fix is to use a pattern already in use in several places in our codebase.
Use the custom deleter parameter of std::shared_ptr to call deleteLater() instead of destroying the object in place.
This allows any thread to use shared_ptrs of SpatiallyNestables without fear.

interface/src/avatar/AvatarManager.cpp

@@ -53,7 +53,7 @@ const QUuid MY_AVATAR_KEY;  // NULL key
 
 AvatarManager::AvatarManager(QObject* parent) :
     _avatarsToFade(),
-    _myAvatar(std::make_shared<MyAvatar>(qApp->thread()))
+    _myAvatar(new MyAvatar(qApp->thread()), [](MyAvatar* ptr) { ptr->deleteLater(); })
 {
     // register a meta type for the weak pointer we'll use for the owning avatar mixer for each avatar
     qRegisterMetaType<QWeakPointer<Node> >("NodeWeakPointer");
@@ -297,7 +297,7 @@ void AvatarManager::simulateAvatarFades(float deltaTime) {
 }
 
 AvatarSharedPointer AvatarManager::newSharedAvatar() {
-    return std::make_shared<OtherAvatar>(qApp->thread());
+    return AvatarSharedPointer(new OtherAvatar(qApp->thread()), [](OtherAvatar* ptr) { ptr->deleteLater(); });
 }
 
 void AvatarManager::handleRemovedAvatar(const AvatarSharedPointer& removedAvatar, KillAvatarReason removalReason) {

interface/src/ui/overlays/Overlays.cpp

@@ -161,33 +161,33 @@ OverlayID Overlays::addOverlay(const QString& type, const QVariant& properties)
     Overlay::Pointer thisOverlay = nullptr;
 
     if (type == ImageOverlay::TYPE) {
-        thisOverlay = std::make_shared<ImageOverlay>();
+        thisOverlay = Overlay::Pointer(new ImageOverlay(), [](Overlay* ptr) { ptr->deleteLater(); });
     } else if (type == Image3DOverlay::TYPE || type == "billboard") { // "billboard" for backwards compatibility
-        thisOverlay = std::make_shared<Image3DOverlay>();
+        thisOverlay = Overlay::Pointer(new Image3DOverlay(), [](Overlay* ptr) { ptr->deleteLater(); });
     } else if (type == TextOverlay::TYPE) {
-        thisOverlay = std::make_shared<TextOverlay>();
+        thisOverlay = Overlay::Pointer(new TextOverlay(), [](Overlay* ptr) { ptr->deleteLater(); });
     } else if (type == Text3DOverlay::TYPE) {
-        thisOverlay = std::make_shared<Text3DOverlay>();
+        thisOverlay = Overlay::Pointer(new Text3DOverlay(), [](Overlay* ptr) { ptr->deleteLater(); });
     } else if (type == Shape3DOverlay::TYPE) {
-        thisOverlay = std::make_shared<Shape3DOverlay>();
+        thisOverlay = Overlay::Pointer(new Shape3DOverlay(), [](Overlay* ptr) { ptr->deleteLater(); });
     } else if (type == Cube3DOverlay::TYPE) {
-        thisOverlay = std::make_shared<Cube3DOverlay>();
+        thisOverlay = Overlay::Pointer(new Cube3DOverlay(), [](Overlay* ptr) { ptr->deleteLater(); });
     } else if (type == Sphere3DOverlay::TYPE) {
-        thisOverlay = std::make_shared<Sphere3DOverlay>();
+        thisOverlay = Overlay::Pointer(new Sphere3DOverlay(), [](Overlay* ptr) { ptr->deleteLater(); });
     } else if (type == Circle3DOverlay::TYPE) {
-        thisOverlay = std::make_shared<Circle3DOverlay>();
+        thisOverlay = Overlay::Pointer(new Circle3DOverlay(), [](Overlay* ptr) { ptr->deleteLater(); });
     } else if (type == Rectangle3DOverlay::TYPE) {
-        thisOverlay = std::make_shared<Rectangle3DOverlay>();
+        thisOverlay = Overlay::Pointer(new Rectangle3DOverlay(), [](Overlay* ptr) { ptr->deleteLater(); });
     } else if (type == Line3DOverlay::TYPE) {
-        thisOverlay = std::make_shared<Line3DOverlay>();
+        thisOverlay = Overlay::Pointer(new Line3DOverlay(), [](Overlay* ptr) { ptr->deleteLater(); });
     } else if (type == Grid3DOverlay::TYPE) {
-        thisOverlay = std::make_shared<Grid3DOverlay>();
+        thisOverlay = Overlay::Pointer(new Grid3DOverlay(), [](Overlay* ptr) { ptr->deleteLater(); });
     } else if (type == ModelOverlay::TYPE) {
-        thisOverlay = std::make_shared<ModelOverlay>();
+        thisOverlay = Overlay::Pointer(new ModelOverlay(), [](Overlay* ptr) { ptr->deleteLater(); });
     } else if (type == Web3DOverlay::TYPE) {
-        thisOverlay = std::make_shared<Web3DOverlay>();
+        thisOverlay = Overlay::Pointer(new Web3DOverlay(), [](Overlay* ptr) { ptr->deleteLater(); });
     } else if (type == RectangleOverlay::TYPE) {
-        thisOverlay = std::make_shared<RectangleOverlay>();
+        thisOverlay = Overlay::Pointer(new RectangleOverlay(), [](Overlay* ptr) { ptr->deleteLater(); });
     }
 
     if (thisOverlay) {
@@ -230,7 +230,7 @@ OverlayID Overlays::cloneOverlay(OverlayID id) {
     Overlay::Pointer thisOverlay = getOverlay(id);
 
     if (thisOverlay) {
-        OverlayID cloneId = addOverlay(Overlay::Pointer(thisOverlay->createClone()));
+        OverlayID cloneId = addOverlay(Overlay::Pointer(thisOverlay->createClone(), [](Overlay* ptr) { ptr->deleteLater(); }));
 #if OVERLAY_PANELS
         auto attachable = std::dynamic_pointer_cast<PanelAttachable>(thisOverlay);
         if (attachable && attachable->getParentPanel()) {

libraries/entities-renderer/src/RenderableModelEntityItem.cpp

@@ -60,7 +60,8 @@ bool ModelEntityWrapper::isModelLoaded() const {
 }
 
 EntityItemPointer RenderableModelEntityItem::factory(const EntityItemID& entityID, const EntityItemProperties& properties) {
-    EntityItemPointer entity{ new RenderableModelEntityItem(entityID, properties.getDimensionsInitialized()) };
+    EntityItemPointer entity(new RenderableModelEntityItem(entityID, properties.getDimensionsInitialized()),
+                             [](EntityItem* ptr) { ptr->deleteLater(); });
     entity->setProperties(properties);
     return entity;
 }

libraries/entities-renderer/src/RenderablePolyVoxEntityItem.cpp

@@ -138,7 +138,7 @@ void loop3(const T& start, const T& end, F f) {
 }
 
 EntityItemPointer RenderablePolyVoxEntityItem::factory(const EntityItemID& entityID, const EntityItemProperties& properties) {
-    std::shared_ptr<RenderablePolyVoxEntityItem> entity{ new RenderablePolyVoxEntityItem(entityID) };
+    std::shared_ptr<RenderablePolyVoxEntityItem> entity(new RenderablePolyVoxEntityItem(entityID), [](EntityItem* ptr) { ptr->deleteLater(); });
     entity->setProperties(properties);
     entity->initializePolyVox();
     return entity;

libraries/entities/src/LightEntityItem.cpp

@@ -30,7 +30,7 @@ const float LightEntityItem::DEFAULT_CUTOFF = PI / 2.0f;
 bool LightEntityItem::_lightsArePickable = false;
 
 EntityItemPointer LightEntityItem::factory(const EntityItemID& entityID, const EntityItemProperties& properties) {
-    EntityItemPointer entity { new LightEntityItem(entityID) };
+    EntityItemPointer entity(new LightEntityItem(entityID), [](EntityItem* ptr) { ptr->deleteLater(); });
     entity->setProperties(properties);
     return entity;
 }

libraries/entities/src/LineEntityItem.cpp

@@ -26,7 +26,7 @@ const int LineEntityItem::MAX_POINTS_PER_LINE = 70;
 
 
 EntityItemPointer LineEntityItem::factory(const EntityItemID& entityID, const EntityItemProperties& properties) {
-    EntityItemPointer entity { new LineEntityItem(entityID) };
+    EntityItemPointer entity(new LineEntityItem(entityID), [](EntityItem* ptr) { ptr->deleteLater(); });
     entity->setProperties(properties);
     return entity;
 }
@@ -214,4 +214,4 @@ void LineEntityItem::resetPointsChanged() {
     withWriteLock([&] {
         _pointsChanged = false;
     });
-}
+}

libraries/entities/src/ModelEntityItem.cpp

@@ -26,7 +26,7 @@ const QString ModelEntityItem::DEFAULT_MODEL_URL = QString("");
 const QString ModelEntityItem::DEFAULT_COMPOUND_SHAPE_URL = QString("");
 
 EntityItemPointer ModelEntityItem::factory(const EntityItemID& entityID, const EntityItemProperties& properties) {
-    EntityItemPointer entity { new ModelEntityItem(entityID) };
+    EntityItemPointer entity(new ModelEntityItem(entityID), [](EntityItem* ptr) { ptr->deleteLater(); });
     entity->setProperties(properties);
     return entity;
 }

libraries/entities/src/ParticleEffectEntityItem.cpp

@@ -147,7 +147,7 @@ uint64_t Properties::emitIntervalUsecs() const {
 
 
 EntityItemPointer ParticleEffectEntityItem::factory(const EntityItemID& entityID, const EntityItemProperties& properties) {
-    EntityItemPointer entity { new ParticleEffectEntityItem(entityID) };
+    EntityItemPointer entity(new ParticleEffectEntityItem(entityID), [](EntityItem* ptr) { ptr->deleteLater(); });
     entity->setProperties(properties);
     return entity;
 }

libraries/entities/src/PolyLineEntityItem.cpp

@@ -26,7 +26,7 @@ const int PolyLineEntityItem::MAX_POINTS_PER_LINE = 70;
 
 
 EntityItemPointer PolyLineEntityItem::factory(const EntityItemID& entityID, const EntityItemProperties& properties) {
-    EntityItemPointer entity{ new PolyLineEntityItem(entityID) };
+    EntityItemPointer entity(new PolyLineEntityItem(entityID), [](EntityItem* ptr) { ptr->deleteLater(); });
     entity->setProperties(properties);
     return entity;
 }

libraries/entities/src/PolyVoxEntityItem.cpp

@@ -47,7 +47,7 @@ const QString PolyVoxEntityItem::DEFAULT_Y_TEXTURE_URL = QString("");
 const QString PolyVoxEntityItem::DEFAULT_Z_TEXTURE_URL = QString("");
 
 EntityItemPointer PolyVoxEntityItem::factory(const EntityItemID& entityID, const EntityItemProperties& properties) {
-    EntityItemPointer entity { new PolyVoxEntityItem(entityID) };
+    EntityItemPointer entity(new PolyVoxEntityItem(entityID), [](EntityItem* ptr) { ptr->deleteLater(); });
     entity->setProperties(properties);
     return entity;
 }

libraries/entities/src/ShapeEntityItem.cpp

@@ -52,7 +52,7 @@ namespace entity {
 }
 
 ShapeEntityItem::Pointer ShapeEntityItem::baseFactory(const EntityItemID& entityID, const EntityItemProperties& properties) {
-    Pointer entity { new ShapeEntityItem(entityID) };
+    Pointer entity(new ShapeEntityItem(entityID), [](EntityItem* ptr) { ptr->deleteLater(); });
     entity->setProperties(properties);
     return entity;
 }

libraries/entities/src/TextEntityItem.cpp

@@ -30,7 +30,7 @@ const xColor TextEntityItem::DEFAULT_BACKGROUND_COLOR = { 0, 0, 0};
 const bool TextEntityItem::DEFAULT_FACE_CAMERA = false;
 
 EntityItemPointer TextEntityItem::factory(const EntityItemID& entityID, const EntityItemProperties& properties) {
-    EntityItemPointer entity { new TextEntityItem(entityID) };
+    EntityItemPointer entity(new TextEntityItem(entityID), [](EntityItem* ptr) { ptr->deleteLater(); });
     entity->setProperties(properties);
     return entity;
 }

libraries/entities/src/WebEntityItem.cpp

@@ -24,7 +24,7 @@
 const QString WebEntityItem::DEFAULT_SOURCE_URL("http://www.google.com");
 
 EntityItemPointer WebEntityItem::factory(const EntityItemID& entityID, const EntityItemProperties& properties) {
-    EntityItemPointer entity { new WebEntityItem(entityID) };
+    EntityItemPointer entity(new WebEntityItem(entityID), [](EntityItem* ptr) { ptr->deleteLater(); });
     entity->setProperties(properties);
     return entity;
 }

libraries/entities/src/ZoneEntityItem.cpp

@@ -32,7 +32,7 @@ const bool ZoneEntityItem::DEFAULT_GHOSTING_ALLOWED = true;
 const QString ZoneEntityItem::DEFAULT_FILTER_URL = "";
 
 EntityItemPointer ZoneEntityItem::factory(const EntityItemID& entityID, const EntityItemProperties& properties) {
-    EntityItemPointer entity { new ZoneEntityItem(entityID) };
+    EntityItemPointer entity(new ZoneEntityItem(entityID), [](EntityItem* ptr) { ptr->deleteLater(); });
     entity->setProperties(properties);
     return entity;
 }