Merge branch 'fixes' into 'master'

Fix unregisterSystem function

See merge request Mergul/bubel-ecs!26

source/bubel/ecs/hash_map.d

@@ -341,7 +341,7 @@ nothrow:
 		int result;
 		foreach (ref Key k; this)
 		{
-			result = (cast(int delegate(ref Key k) nothrow)dg)(k);
+			result = (cast(int delegate(ref Key k) nothrow @nogc)dg)(k);
 			if (result)
 				break;
 		}
@@ -353,7 +353,7 @@ nothrow:
 		int result;
 		foreach (ref Value v; this)
 		{
-			result = (cast(int delegate(ref Value v) nothrow)dg)(v);
+			result = (cast(int delegate(ref Value v) nothrow @nogc)dg)(v);
 			if (result)
 				break;
 		}
@@ -365,7 +365,7 @@ nothrow:
 		int result;
 		foreach (ref Key k, ref Value v; this)
 		{
-			result = (cast(int delegate(ref Key k, ref Value v) nothrow)dg)(k, v);
+			result = (cast(int delegate(ref Key k, ref Value v) nothrow @nogc)dg)(k, v);
 			if (result)
 				break;
 		}

source/bubel/ecs/manager.d

@@ -76,7 +76,7 @@ export struct EntityManager
                 UpdatePass* pass = Mallocator.make!UpdatePass;
                 pass.name = Mallocator.makeArray(cast(char[]) "update");
                 passes.add(pass);
-                passes_map.add(cast(string) pass.name, cast(ushort)(passes.length - 1));
+                passes_map.add(cast(const(char)[]) pass.name, cast(ushort)(passes.length - 1));
             }
         }
     }
@@ -84,7 +84,7 @@ export struct EntityManager
     /************************************************************************************************************************
     Deinitialize and destroy ECS. This function release whole memory.
     */
-    export static void destroy()
+    export static void destroy() nothrow @nogc
     {
         if (gEntityManager is null)
             return;
@@ -334,16 +334,23 @@ export struct EntityManager
     */
     void unregisterSystem(Sys)()
     {
-        assert(register_state, "unregisterSystem must be called between beginRegister() and endRegister().");
-
         ushort system_id = becsID!Sys;
         System* system = getSystem(system_id);
 
-        assert(system, "System was not registered");
+        unregisterSystem(system);
+    }
+
+    /************************************************************************************************************************
+    Unregister given system form EntityManager.
+    */
+    export void unregisterSystem(System* system) nothrow @nogc
+    {
+        assert(register_state, "unregisterSystem must be called between beginRegister() and endRegister().");
+        assert(system !is null, "System was not registered");
         assert(system.isAlive, "System already unregistered");
         
-        system.destroy();
+        //disable, destroy and dispose user created system but keep name and other data
-        *system = System.init;
+        system.destroySystemData();
     }
 
     /************************************************************************************************************************
@@ -1248,7 +1255,8 @@ export struct EntityManager
     }
 
     /************************************************************************************************************************
-    Return system ECS api by id
+    Return system ECS api by id.
+    System pointer might become invalid after registration process. It should be get once again after new systems are registered.
     */
     export System* getSystem(ushort id) nothrow @nogc
     {

source/bubel/ecs/system.d

@@ -97,38 +97,92 @@ struct System
         return m_system_pointer != null;
     }
 
+    /************************************************************************************************************************
+    Return pointer to user side system object
+    */
+    export void* ptr() nothrow @nogc
+    {
+        return m_system_pointer;
+    }
+
 package:
 
-    void destroy()
+    ///destory system. Dispose all data
+    void destroy() nothrow @nogc
+    {
+        import bubel.ecs.std : Mallocator;
+
+        destroySystemData();
+
+        if (m_name)
+        {
+            Mallocator.dispose(m_name);
+            m_name = null;
+        }
+    }
+
+    ///destroy all system data but keeps name which is used for case of system re-registration
+    void destroySystemData() nothrow @nogc
     {
         import bubel.ecs.std : Mallocator;
         disable();
         if (m_destroy)
-            (cast(void function(void*)) m_destroy)(m_system_pointer);
+        {
+            (cast(void function(void*) nothrow @nogc) m_destroy)(m_system_pointer);
+            m_destroy = null;
+        }
 
-        if (m_name)
-            Mallocator.dispose(m_name);
         if (m_components)
+        {
             Mallocator.dispose(m_components);
+            m_components = null;
+        }
         if (m_excluded_components)
+        {
             Mallocator.dispose(m_excluded_components);
+            m_excluded_components = null;
+        }
         if (m_optional_components)
+        {
             Mallocator.dispose(m_optional_components);
+            m_optional_components = null;
+        }
         if (jobs)
+        {
             Mallocator.dispose(jobs);
+            jobs = null;
+        }
         if (m_read_only_components)
+        {
             Mallocator.dispose(m_read_only_components);
+            m_read_only_components = null;
+        }
         if (m_writable_components)
+        {
             Mallocator.dispose(m_writable_components);
+            m_writable_components = null;
+        }
         if (m_readonly_dependencies)
+        {
             Mallocator.dispose(m_readonly_dependencies);
+            m_readonly_dependencies = null;
+        }
         if (m_writable_dependencies)
+        {
             Mallocator.dispose(m_writable_dependencies);
+            m_writable_dependencies = null;
+        }
         if (m_event_callers)
+        {
             Mallocator.dispose(m_event_callers);
+            m_event_callers = null;
+        }
 
         if (m_system_pointer)
+        {
             Mallocator.dispose(m_system_pointer);
+            m_system_pointer = null;
+        }
     }
 
     struct EventCaller