Throw an exception if a future object couldn't be created

[libs/datafile.git] / source / collection.h

diff --git a/source/collection.h b/source/collection.h
index b2c91d6879c82ef486b9b29b78f0f4054779dd59..c83b4376d20b2b6d4854b29dfc0fbda9c0c286b5 100644 (file)
--- a/source/collection.h
+++ b/source/collection.h
@@ -55,34 +55,27 @@ public:
                template<typename T> friend class CollectionItemType;
 
        private:
-               template<typename T, typename S, bool = NeedsCollection<typename T::Loader>::value>
-               struct Add;
-
                Collection &coll;
 
        public:
                Loader(Collection &);
                Collection &get_object() const { return coll; }
        private:
-               template<typename T, typename S, typename C>
-               void coll_item(const std::string &n)
-               {
-                       RefPtr<T> it = new T;
-                       load_sub(*it, dynamic_cast<C &>(coll));
-                       coll.add<S>(n, it.get());
-                       it.release();
-               }
-
                template<typename T, typename S>
                void item(const std::string &n)
                {
                        RefPtr<T> it = new T;
-                       load_sub(*it);
+                       ItemLoader<T> ldr(*it, coll);
+                       load_sub_with(ldr);
                        coll.add<S>(n, it.get());
                        it.release();
                }
        };
 
+protected:
+       template<typename T, bool = NeedsCollection<typename T::Loader>::value>
+       class ItemLoader;
+
 private:
        typedef std::map<std::string, Variant> ItemMap;
        typedef std::list<CollectionItemTypeBase *> TypeList;
@@ -137,8 +130,14 @@ protected:
                insert_unique(items, name, ptr);
        }
 
+       /** Adds the name of a future object, guessing its type.  If a type matching
+       the name can't be found, nothing is done. */
        void add_future(const std::string &name);
 
+       /** Adds the name of a future object, using a keyword to determine its type.
+       The keyword must be known to the collection. */
+       void add_future_with_keyword(const std::string &name, const std::string &);
+
 public:
        /// Gets a typed object from the collection.
        template<typename T>
@@ -272,19 +271,22 @@ protected:
        CollectionItemType<T> &add_type();
 };
 
-
-template<typename T, typename S>
-struct Collection::Loader::Add<T, S, false>
+template<typename T>
+class Collection::ItemLoader<T, false>: public T::Loader
 {
-       static void add(Loader &loader, const std::string &kwd)
-       { loader.add(kwd, &Loader::item<T, S>); }
+public:
+       ItemLoader(T &o, Collection &):
+               T::Loader(o)
+       { }
 };
 
-template<typename T, typename S>
-struct Collection::Loader::Add<T, S, true>
+template<typename T>
+class Collection::ItemLoader<T, true>: public T::Loader
 {
-       static void add(Loader &loader, const std::string &kwd)
-       { loader.add(kwd, &Loader::coll_item<T, S, typename T::Loader::Collection>); }
+public:
+       ItemLoader(T &o, Collection &c):
+               T::Loader(o, dynamic_cast<typename T::Loader::Collection &>(c))
+       { }
 };
 
 
@@ -312,11 +314,12 @@ public:
        virtual ~CollectionItemTypeBase();
 
        void set_keyword(const std::string &);
+       const std::string &get_keyword() const { return kwd; }
        void add_suffix(const std::string &);
+       bool match_name(const std::string &) const;
        virtual void add_to_loader(Collection::Loader &) const = 0;
        virtual bool can_create() const = 0;
        virtual void create_item(Collection &, const std::string &) const = 0;
-       bool match_name(const std::string &) const;
        virtual Variant create_future() const = 0;
 
        template<typename T>
@@ -383,7 +386,7 @@ private:
                { return RefPtr<S>(0); }
 
                virtual void add_to_loader(Collection::Loader &loader, const std::string &kwd)
-               { Collection::Loader::Add<T, S>::add(loader, kwd); }
+               { loader.add(kwd, &Collection::Loader::item<T, S>); }
        };
 
        CreatorBase *creat;
@@ -482,7 +485,10 @@ T &Collection::get(const std::string &name)
                if((*j)->can_create() && (*j)->check_type<NCT>())
                        (*j)->create_item(*this, name);
 
-       return *get_item(items, name).value<RefPtr<NCT> >();
+       NCT *ptr = get_item(items, name).value<RefPtr<NCT> >().get();
+       if(!ptr)
+               throw key_error(typeid(ItemMap));
+       return *ptr;
 }
 
 template<typename T>