While this class can be instantiated by itself and used for storing objects,
loading requires that a subclass defines the supported types. See the add_type
method for details.
+
+Collections also support a notion of "future objects". These are objects which
+are known to be possible to load, but loading them is deferred to the first
+time they are requested.
*/
class Collection
{
if(!item)
throw std::invalid_argument("Collection::add(item)");
- RefPtr<typename RemoveConst<T>::Type> ptr(item);
- try
- {
- insert_unique(items, name, ptr);
- }
- catch(...)
+ typedef RefPtr<typename RemoveConst<T>::Type> RPNCT;
+
+ ItemMap::iterator i = items.find(name);
+ if(i!=items.end())
{
- // Avoid deleting the object
- ptr.release();
- throw;
+ if(i->second.check_type<RPNCT>())
+ {
+ // Replace a future object placeholder
+ RPNCT &ptr = i->second.value<RPNCT>();
+ if(!ptr)
+ {
+ ptr = item;
+ return;
+ }
+ }
+
+ throw key_error(typeid(ItemMap));
}
+
+ items.insert(ItemMap::value_type(name, RPNCT(item)));
+ }
+
+protected:
+ /** Adds the name of a future object to the collection. The object itself
+ will be loaded on first access. The calling subclass should be prepared to
+ create the object on request. */
+ template<typename T>
+ void add_future(const std::string &name)
+ {
+ RefPtr<typename RemoveConst<T>::Type> ptr(0);
+ insert_unique(items, name, ptr);
}
+ void add_future(const std::string &name);
+
+public:
/// Gets a typed object from the collection.
template<typename T>
T &get(const std::string &name) const
{
typedef typename RemoveConst<T>::Type NCT;
- return *get_item(items, name).value<RefPtr<NCT> >();
+ T *ptr = get_item(items, name).value<RefPtr<NCT> >().get();
+ if(!ptr)
+ throw key_error(typeid(ItemMap));
+ return *ptr;
}
/** Gets a typed object from the collection. If the name is not found in
template<typename T>
T &get(const std::string &);
- /// Returns a list of the names of objects of one type in the collection.
+private:
+ template<typename T>
+ void collect_items(std::list<T *> *objects, std::list<std::string> *names, std::list<std::string> *future_names) const
+ {
+ typedef RefPtr<typename RemoveConst<T>::Type> RPNCT;
+
+ for(ItemMap::const_iterator i=items.begin(); i!=items.end(); ++i)
+ if(i->second.check_type<RPNCT>())
+ {
+ T *ptr = i->second.value<RPNCT>().get();
+ if(ptr)
+ {
+ if(objects)
+ objects->push_back(ptr);
+ if(names)
+ names->push_back(i->first);
+ }
+ else if(future_names)
+ future_names->push_back(i->first);
+ }
+ }
+
+public:
+ /** Returns a list of the names of loaded objects of one type in the
+ collection. */
template<typename T>
std::list<std::string> get_names() const
{
std::list<std::string> result;
- for(ItemMap::const_iterator i=items.begin(); i!=items.end(); ++i)
- if(i->second.check_type<RefPtr<typename RemoveConst<T>::Type> >())
- result.push_back(i->first);
+ collect_items<T>(0, &result, 0);
+ return result;
+ }
+
+ /** Returns a list of the names of objects of one type in the collection,
+ including any future objects. */
+ template<typename T>
+ std::list<std::string> get_names()
+ {
+ std::list<std::string> result;
+ collect_items<T>(0, &result, &result);
return result;
}
- /// Returns a list of objects of one type in the collection.
+ /// Returns a list of loaded objects of one type in the collection.
template<typename T>
std::list<T *> get_list() const
{
- typedef RefPtr<typename RemoveConst<T>::Type> RPNCT;
+ std::list<T *> result;
+ collect_items<T>(&result, 0, 0);
+ return result;
+ }
+ /** Returns a list of objects of one type in the collection. Any future
+ objects of that type are loaded and returned in the list. */
+ template<typename T>
+ std::list<T *> get_list()
+ {
std::list<T *> result;
- for(ItemMap::const_iterator i=items.begin(); i!=items.end(); ++i)
- if(i->second.check_type<RPNCT>())
- result.push_back(i->second.value<RPNCT>().get());
+ std::list<std::string> future;
+ collect_items<T>(&result, 0, &future);
+ for(std::list<std::string>::iterator i=future.begin(); i!=future.end(); ++i)
+ result.push_back(&get<T>(*i));
return result;
}
- /** Checks whether a name exists in the collection. Does not care about the
- type of the object. */
- bool contains(const std::string &n) const;
+private:
+ template<typename T>
+ unsigned get_status(const std::string &name) const
+ {
+ ItemMap::const_iterator i = items.find(name);
+ if(i==items.end())
+ return false;
+
+ typedef RefPtr<typename RemoveConst<T>::Type> RPNCT;
+ if(!i->second.check_type<RPNCT>())
+ return false;
+
+ T *ptr = i->second.value<RPNCT>().get();
+ return ptr ? 1 : 2;
+ }
+
+public:
+ /// Checks whether a typed object exists and is loaded in the collection.
+ template<typename T>
+ bool contains(const std::string &name) const
+ { return get_status<T>(name)==1; }
+
+ /** Checks whether a typed object exists in the collection, as either a
+ loaded or future object. */
+ template<typename T>
+ bool contains(const std::string &name)
+ { return get_status<T>(name)>0; }
/// Returns the name of an item in the collection.
template<typename T>
template<typename T>
class Tag: public TagBase
- {
- public:
- virtual ~Tag() { }
- };
+ { };
std::string kwd;
+ std::vector<std::string> suffixes;
TagBase *tag;
- CollectionItemTypeBase(): tag(0) { }
+ CollectionItemTypeBase();
public:
- virtual ~CollectionItemTypeBase()
- { delete tag; }
+ virtual ~CollectionItemTypeBase();
+ void set_keyword(const std::string &);
+ void add_suffix(const std::string &);
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>
bool check_type() const
virtual ~StoreBase() { }
virtual void store(Collection &, const std::string &, T *) = 0;
+ virtual Variant create_future() const = 0;
virtual void add_to_loader(Collection::Loader &, const std::string &) = 0;
};
virtual void store(Collection &coll, const std::string &name, T *obj)
{ coll.add(name, static_cast<S *>(obj)); }
+ virtual Variant create_future() const
+ { return RefPtr<S>(0); }
+
virtual void add_to_loader(Collection::Loader &loader, const std::string &kwd)
{ Collection::Loader::Add<T, S>::add(loader, kwd); }
};
item's name. */
CollectionItemType &keyword(const std::string &k)
{
- kwd = k;
+ set_keyword(k);
+ return *this;
+ }
+
+ /** Adds a suffix that is used to match names when looking for future
+ objects. There is no implied separator; a name matches if it ends with the
+ suffix. If a keyword is defined before any suffixes, then "."+keyword is
+ added as a suffix. */
+ CollectionItemType &suffix(const std::string &s)
+ {
+ add_suffix(s);
return *this;
}
if(obj)
store->store(coll, name, obj);
}
+
+ virtual Variant create_future() const
+ { return store->create_future(); }
};
{
typedef typename RemoveConst<T>::Type NCT;
- if(!items.count(name))
+ ItemMap::iterator i = items.find(name);
+ if(i!=items.end())
{
- for(TypeList::iterator i=types.begin(); i!=types.end(); ++i)
- if((*i)->can_create() && (*i)->check_type<NCT>())
- (*i)->create_item(*this, name);
+ NCT *ptr = i->second.value<RefPtr<NCT> >().get();
+ if(ptr)
+ return *ptr;
}
+ for(TypeList::iterator j=types.begin(); j!=types.end(); ++j)
+ if((*j)->can_create() && (*j)->check_type<NCT>())
+ (*j)->create_item(*this, name);
+
return *get_item(items, name).value<RefPtr<NCT> >();
}
projects / libs / datafile.git / blobdiff