Couple improvements to the dependency manager

libraries/shared/src/DependencyManager.cpp

@@ -16,17 +16,10 @@ DependencyManager& DependencyManager::getInstance() {
     return instance;
 }
 
-DependencyManager::DependencyManager() {
-    // Guard against request of ourself
-    // We could set the value to this, but since it doesn't make sense to access
-    // the DependencyManager instance from the outside let's set it to NULL
-    _instanceHash.insert(typeid(DependencyManager).name(), NULL);
-}
-
 DependencyManager::~DependencyManager() {
     foreach (Dependency* instance, _instanceHash) {
         if (instance) {
-            instance->deleteInstance();
+            delete instance;
         }
     }
     _instanceHash.clear();

libraries/shared/src/DependencyManager.h

@@ -19,16 +19,24 @@
 
 class DependencyManager {
 public:
+    // Only accessible method.
+    // usage: T* instance = DependencyManager::get<T>();
     template<typename T>
     static T* get();
     
+    // Any class T in the DependencyManager needs to subclass Dependency
+    // They also need to have protected constructor(s) and virtual destructor
+    // As well as declare DependencyManager a friend class
     class Dependency {
-        virtual void deleteInstance() = 0;
+    protected:
+        Dependency() {}
+        virtual ~Dependency() {} // Ensure the proper destruction of the object
         friend DependencyManager;
     };
+    
 private:
     static DependencyManager& getInstance();
-    DependencyManager();
+    DependencyManager() {}
     ~DependencyManager();
     
     typedef QHash<QString, Dependency*> InstanceHash;
@@ -52,4 +60,4 @@ T* DependencyManager::get() {
     return newInstance;
 }
 
-#endif // hifi_DependencyManager_h
+#endif // hifi_DependencyManager_h