From 14cda00ebc46ba02f68bbbd3ae111059d1ccac9c Mon Sep 17 00:00:00 2001
From: Atlante45 <clement.brisset@gmail.com>
Date: Fri, 12 Dec 2014 20:52:41 -0800
Subject: [PATCH] First implementation of the DependencyManager

---
 libraries/shared/src/DependencyManager.cpp | 33 +++++++++++++
 libraries/shared/src/DependencyManager.h   | 55 ++++++++++++++++++++++
 2 files changed, 88 insertions(+)
 create mode 100644 libraries/shared/src/DependencyManager.cpp
 create mode 100644 libraries/shared/src/DependencyManager.h

diff --git a/libraries/shared/src/DependencyManager.cpp b/libraries/shared/src/DependencyManager.cpp
new file mode 100644
index 0000000000..b4b3061317
--- /dev/null
+++ b/libraries/shared/src/DependencyManager.cpp
@@ -0,0 +1,33 @@
+//
+//  DependencyManager.cpp
+//
+//
+//  Created by Clément Brisset on 12/10/14.
+//  Copyright 2014 High Fidelity, Inc.
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+
+#include "DependencyManager.h"
+
+DependencyManager& DependencyManager::getInstance() {
+    static DependencyManager instance;
+    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();
+        }
+    }
+    _instanceHash.clear();
+}
\ No newline at end of file
diff --git a/libraries/shared/src/DependencyManager.h b/libraries/shared/src/DependencyManager.h
new file mode 100644
index 0000000000..690058cab4
--- /dev/null
+++ b/libraries/shared/src/DependencyManager.h
@@ -0,0 +1,55 @@
+//
+//  DependencyManager.h
+//
+//
+//  Created by Clément Brisset on 12/10/14.
+//  Copyright 2014 High Fidelity, Inc.
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+
+#ifndef hifi_DependencyManager_h
+#define hifi_DependencyManager_h
+
+#include <QHash>
+#include <QString>
+
+#include <typeinfo>
+
+class DependencyManager {
+public:
+    template<typename T>
+    static T* get();
+    
+    class Dependency {
+        virtual void deleteInstance() = 0;
+        friend DependencyManager;
+    };
+private:
+    static DependencyManager& getInstance();
+    DependencyManager();
+    ~DependencyManager();
+    
+    typedef QHash<QString, Dependency*> InstanceHash;
+    static InstanceHash& getInstanceHash() { return getInstance()._instanceHash; }
+    InstanceHash _instanceHash;
+};
+
+template <typename T>
+T* DependencyManager::get() {
+    const QString& typeId = typeid(T).name();
+    
+    // Search the hash for global instance
+    Dependency* instance = getInstanceHash().value(typeId, NULL);
+    if (instance) {
+        return dynamic_cast<T*>(instance);
+    }
+
+    // Found no instance in hash so we create one.
+    T* newInstance = new T();
+    getInstanceHash().insert(typeId, dynamic_cast<Dependency*>(newInstance));
+    return newInstance;
+}
+
+#endif // hifi_DependencyManager_h
\ No newline at end of file