3 This file is part of libmspdatafile
4 Copyright © 2006 Mikko Rasa, Mikkosoft Productions
5 Distributed under the LGPL
8 #ifndef MSP_DATAFILE_COLLECTION_H_
9 #define MSP_DATAFILE_COLLECTION_H_
11 #include <msp/core/refptr.h>
18 Helper struct to determine whether a Loader has a Collection typedef.
21 struct NeedsCollection
23 struct Yes { char c[2]; };
24 struct No { char c; };
27 static Yes f(typename U::Collection *);
31 enum { result=(sizeof(f<T>(0))==sizeof(Yes)) };
39 struct RemoveConst<const T>
43 A collection of objects that can be loaded from a datafile. Each object is
44 identified by a name, which must be unique across the entire collection.
52 /* XXX I don't really like sticking all this stuff in here, but there's some
53 complex inter-class relationships, especially between ItemKeyword and
54 Collection::Loader. */
58 virtual ~ItemBase() { }
62 struct Item: public ItemBase
66 Item(T *d): data(d) { }
67 ~Item() { delete data; }
71 Used to store keywords for types that can be loaded.
73 struct ItemKeywordBase
75 virtual void add_to_loader(Loader &) const { };
78 template<typename T, typename S, bool need_coll=NeedsCollection<typename T::Loader>::result>
79 struct ItemKeyword: public ItemKeywordBase
83 ItemKeyword(const std::string &kw): keyword(kw) { }
85 void add_to_loader(Loader &ldr) const
86 { ldr.add(keyword, &Loader::item<T, S>); }
89 template<typename T, typename S>
90 struct ItemKeyword<T, S, true>: public ItemKeywordBase
94 ItemKeyword(const std::string &kw): keyword(kw) { }
96 virtual void add_to_loader(Loader &ldr) const
97 { ldr.add(keyword, &Loader::coll_item<T, S, typename T::Loader::Collection>); }
101 Used to store types that can be created automatically.
103 struct ItemCreatorBase
105 virtual ~ItemCreatorBase() { }
108 bool create(Collection &coll, const std::string &name, S *&ptr)
110 ItemCreatorBridge<S> *creator=dynamic_cast<ItemCreatorBridge<S> *>(this);
113 ptr=creator->create(coll, name);
121 struct ItemCreatorBridge: public ItemCreatorBase
123 virtual S *create(Collection &, const std::string &) const =0;
126 template<typename T, typename S, typename C>
127 struct ItemCreator: public ItemCreatorBridge<S>
129 typedef T *(C::*fCreate)(const std::string &);
133 ItemCreator(fCreate cf): create_func(cf) { }
134 virtual S *create(Collection &coll, const std::string &name) const
135 { return (dynamic_cast<C &>(coll).*create_func)(name); }
140 Loads objects into a Collection.
142 class Loader: public DataFile::Loader
148 Loader(Collection &);
149 Collection &get_object() const { return coll; }
151 template<typename T, typename S, typename C>
152 void coll_item(const std::string &n)
155 load_sub(*it, dynamic_cast<C &>(coll));
156 coll.add<S>(n, it.get());
160 template<typename T, typename S>
161 void item(const std::string &n)
165 coll.add<S>(n, it.get());
169 template<typename, typename, bool> friend class ItemKeyword;
173 typedef std::map<std::string, ItemBase *> ItemMap;
174 typedef std::list<ItemKeywordBase *> ItemKeywordSeq;
175 typedef std::list<ItemCreatorBase *> ItemCreatorSeq;
178 ItemKeywordSeq keywords;
179 ItemCreatorSeq creators;
181 Collection(const Collection &);
182 Collection &operator=(const Collection &);
185 virtual ~Collection();
188 Adds an object into the collection. If a name collision occurs, an
189 exception is thrown. The collection takes ownership of the object.
192 void add(const std::string &name, T *d)
194 if(items.count(name))
195 throw KeyError("Duplicate key in collection", name);
197 items[name]=new Item<typename RemoveConst<T>::Type>(d);
201 Gets an object of a specific type from the collection.
204 T *get(const std::string &name) const
206 typedef typename RemoveConst<T>::Type NCT;
208 ItemMap::const_iterator i=items.find(name);
210 throw KeyError("Item not found in collection", name);
212 const Item<NCT> *item=dynamic_cast<const Item<NCT> *>(i->second);
214 throw TypeError("Type mismatch on item '"+name+"'");
220 Gets an object of a specific type from the collection. If the name is not
221 found in the collection and there is a creator for the item type, it is
225 T *get(const std::string &name)
227 typedef typename RemoveConst<T>::Type NCT;
229 ItemMap::const_iterator i=items.find(name);
232 for(ItemCreatorSeq::iterator j=creators.begin(); j!=creators.end(); ++j)
235 if((*j)->create(*this, name, d))
237 // We already know that the item didn't exist yet
238 items[name]=new Item<NCT>(d);
242 throw KeyError("Item not found in collection", name);
245 const Item<NCT> *item=dynamic_cast<const Item<NCT> *>(i->second);
247 throw TypeError("Type mismatch on item '"+name+"'");
253 Returns a list of the names of objects of a specific type in the collection.
256 std::list<std::string> get_names() const
258 std::list<std::string> result;
259 for(ItemMap::const_iterator i=items.begin(); i!=items.end(); ++i)
260 if(dynamic_cast<const Item<typename RemoveConst<T>::Type> *>(i->second))
261 result.push_back(i->first);
266 Returns a list of objects of a specific type in the collection.
269 std::list<T *> get_list() const
271 typedef typename RemoveConst<T>::Type NCT;
273 std::list<T *> result;
274 for(ItemMap::const_iterator i=items.begin(); i!=items.end(); ++i)
275 if(Item<NCT> *item=dynamic_cast<Item<NCT> *>(i->second))
276 result.push_back(item->data);
281 Checks whether a name exists in the collection. Does not care about the
284 bool contains(const std::string &n) const;
288 Adds a type that can be loaded from datafiles.
291 void add_keyword(const std::string &keyword)
292 { add_keyword<T, T>(keyword); }
295 Adds a type that can be loaded from datafiles, with different storage type.
297 template<typename T, typename S>
298 void add_keyword(const std::string &keyword)
299 { keywords.push_back(new ItemKeyword<T, S>(keyword)); }
302 Adds a type that can be created automatically.
304 template<typename T, typename C>
305 void add_creator(T *(C::*func)(const std::string &))
306 { add_creator<T, T, C>(func); }
308 template<typename T, typename S, typename C>
309 void add_creator(T *(C::*func)(const std::string &))
310 { creators.push_back(new ItemCreator<T, S, C>(func)); }
313 } // namespace DataFile