comparison base/ById.h @ 1752:6d09d68165a4 by-id

Further review of ById: make IDs only available when adding a model to the ById store, not by querying the item directly. This means any id encountered in the wild must have been added to the store at some point (even if later released), which simplifies reasoning about lifecycles

         m_id(IdAlloc::getNextId()) {
     }
     virtual ~WithId() {
     }
 
+protected:
+    friend class AnyById;
+    
     /**
      * Return an id for this object. The id is a unique number for
      * this object among all objects that implement WithId within this
      * single run of the application.
      */

 public:
     typedef TypedId<T> Id;
     
     WithTypedId() : WithId() { }
 
+protected:
+    template <typename Item, typename Id>
+    friend class TypedById;
+    
     /**
      * Return an id for this object. The id is a unique value for this
      * object among all objects that implement WithTypedId within this
      * single run of the application.
      */

 };
 
 class AnyById
 {
 public:
-    static void add(int, std::shared_ptr<WithId>);
+    static int add(std::shared_ptr<WithId>);
     static void release(int);
     static std::shared_ptr<WithId> get(int); 
 
     template <typename Derived>
     static bool isa(int id) {

 template <typename Item, typename Id>
 class TypedById
 {
 public:
     static Id add(std::shared_ptr<Item> item) {
-        auto id = item->getId();
-        if (id.isNone()) {
-            throw std::logic_error("item id should never be None");
-        }
-        AnyById::add(id.untyped, item);
+        Id id;
+        id.untyped = AnyById::add(item);
         return id;
     }
 
     static void release(Id id) {
         AnyById::release(id.untyped);

     }
 
     static std::shared_ptr<Item> get(Id id) {
         return getAs<Item>(id);
     }
-
+    
     /**
      * If the Item type is an XmlExportable, return the export ID of
      * the given item ID. A call to this function will fail to compile
      * if the Item is not an XmlExportable.
      *