+ /**
+ * Register a type with the extension of files which this type can
+ * load. If any type has already been registered with the given file
+ * extension, it will be replaced.
+ * \param extension The file extension.
+ */
+ template <class T>
+ static void register_type(const std::string& extension)
+ {
+ //if (!type_lookup_) type_lookup_ = type_lookup_ptr(new type_lookup);
+ loader_ptr loader(new specific_loader<T>);
+ //(*type_lookup_)[extension] = loader;
+ //type_lookup_[extension] = loader;
+ manage_loader(extension, loader, true);
+ }
+
+ /**
+ * Unregister the type associated with a file extension. Resources of
+ * this type will no longer be loadable, although resources which are
+ * already loaded will remain loaded.
+ * \param extension The file extension
+ */
+ static void unregister_type(const std::string& extension)
+ {
+ //type_lookup_.erase(extension);
+ //type_lookup_->erase(extension);
+ loader_ptr loader;
+ manage_loader(extension, loader, true);
+ }
+
+
+ static resource_ptr load(const std::string& path);
+
+ static resource_ptr reload(std::string& path);
+
+
+ /**
+ * Construct a resource container.
+ * \param ptr A pointer to the underlying resource data.
+ */
+ template <class T>
+ explicit resource(T* ptr) :
+ resource_(ptr),
+ typeinfo_(const_cast<std::type_info*>(&typeid(T))),
+ unloader_(new specific_unloader<T>(ptr)) {}
+
+ /**
+ * Deconstruct a resource container.
+ */
+ virtual ~resource();
+
+
+ /**
+ * Reload the resource data. This will cause the resource file to be
+ * reread, and the underlying resource data will change.
+ */
+ void reload();
+
+
+ /**
+ * Get whether or not the type of the underlying resource data matches
+ * an expected type.
+ * \return True if the types match, false otherwise.
+ */
+ template <class T>
+ bool check() const
+ {
+ return *typeinfo_ == typeid(T);
+ }
+
+ /**
+ * Get a pointer to the underlying resource data as long as the type of
+ * the resource data matches the expected type.
+ * \return The resource data, or null if there is a type mismatch.
+ */
+ template <class T>
+ T* get() const
+ {
+ if (check<T>()) return (T*)resource_;
+ return 0;
+ }
+
+
+ /**
+ * Reloads some resources which have been modified on disk since they
+ * were loaded. Hotloading must have been enabled at compile-time.
+ * \return The number of resources reloaded.
+ */
+ static int reload_as_needed();
+
+ static void print_types();
+
+
+private:
+
+ class loader
+ {
+ public:
+
+ virtual ~loader() {}
+
+ virtual resource* load(const std::string& path)
+ {
+ return 0;
+ }
+ };
+
+ typedef boost::shared_ptr<loader> loader_ptr;
+
+ template <class T>
+ class specific_loader : public loader
+ {
+ public:
+
+ virtual resource* load(const std::string& path)
+ {
+ log_info("loading resource of type ", typeid(T).name());
+ return new resource(new T(path));
+ }
+ };
+
+
+ class unloader
+ {
+ public:
+
+ virtual ~unloader() {};
+ };
+
+ typedef boost::shared_ptr<unloader> unloader_ptr;
+
+ template <class T>
+ class specific_unloader : public unloader
+ {
+ public:
+
+ specific_unloader(T* object = 0) :
+ object_(object) {}
+
+ virtual ~specific_unloader()
+ {
+ log_info("unloading resource of type ", typeid(T).name());
+ delete object_;
+ }
+
+
+ private:
+
+ T* object_;
+ };
+
+
+ void set_loader(const std::string& path, loader_ptr loader)
+ {
+ path_ = path;
+ loader_ = loader;
+ }
+
+
+ void* resource_;
+ std::type_info* typeinfo_;
+ unloader_ptr unloader_;
+
+ std::string path_;
+ loader_ptr loader_;
+
+ typedef std::map<std::string,loader_ptr> type_lookup;
+ //typedef boost::shared_ptr<type_lookup> type_lookup_ptr;
+ //static type_lookup_ptr type_lookup_;
+ //static type_lookup type_lookup_;
+
+ static void manage_loader(const std::string& extension, loader_ptr& loader, bool set = false);
+
+#ifdef USE_HOTLOADING
+ int wd_;
+
+ void set_watch_descriptor(int wd)
+ {
+ wd_ = wd;
+ }
+#endif
+};
+
+
+/**
+ * The resource handle class provides a nicer way to work with resources.
+ * It allows you to work with a resource pointer as if you already know the
+ * type of the resource.
+ */
+template <class T>
+class resource_handle
+{
+public:
+
+ /**
+ * Construct a null resource handle.
+ */
+ resource_handle() {}
+
+ /**
+ * Construct a resource handle.
+ * \param ptr The resource pointer to reference.
+ */
+ resource_handle(resource_ptr ptr) :
+ resource_(ptr) {}
+
+
+ /**
+ * Get whether or not the handle is dereferenceable to the type of this
+ * handle. A resource handle is dereferenceable if it is not a null
+ * handle and if its underlying resource is in fact the same type as is
+ * expected by the handle.
+ * \return True if the handle is dereferenceable, false otherwise.
+ */
+ operator bool () const
+ {
+ if (!resource_) return false;
+ return resource_->check<T>();
+ }
+
+
+ /**
+ * Get a pointer to the underlying resource.
+ * \return The pointer, or null if this handle is not dereferenceable.
+ */
+ T* get() const
+ {
+ if (!*this) return 0;
+ return resource_->get<T>();
+ }
+
+ /**
+ * Dereference the handle all the way to the underlying resource.
+ * \return A reference to the resource.
+ * \throws std::runtime_error If this is a null handle.
+ */
+ T& get_reference() const
+ {
+ if (!*this) throw std::runtime_error("dereference null handle");
+ return *(resource_->get<T>());
+ }
+
+
+ /**
+ * Same as get() for getting a pointer to the underlying resources.
+ * \return The pointer, or null if this handle is not dereferenceable.
+ */
+ T* operator -> () const
+ {
+ return get();
+ }
+
+ /**
+ * Same a get_reference() for dereferencing the handle.
+ * \return A reference to the resource.
+ * \throws std::runtime_error If this is a null handle.
+ */
+ T& operator * () const
+ {
+ return get_reference();
+ }
+
+