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 S *create(Collection &coll, const std::string &name)
110 ItemCreatorBridge<S> *creator=dynamic_cast<ItemCreatorBridge<S> *>(this);
112 return creator->create(coll, name);
118 struct ItemCreatorBridge: public ItemCreatorBase
120 virtual S *create(Collection &, const std::string &) const =0;
123 template<typename T, typename S, typename C>
124 struct ItemCreator: public ItemCreatorBridge<S>
126 typedef T *(C::*fCreate)(const std::string &);
130 ItemCreator(fCreate cf): create_func(cf) { }
131 virtual S *create(Collection &coll, const std::string &name) const
132 { return (dynamic_cast<C &>(coll).*create_func)(name); }
137 Loads objects into a Collection.
139 class Loader: public DataFile::Loader
145 Loader(Collection &);
146 Collection &get_object() const { return coll; }
148 template<typename T, typename S, typename C>
149 void coll_item(const std::string &n)
152 load_sub(*it, dynamic_cast<C &>(coll));
153 coll.add<S>(n, it.get());
157 template<typename T, typename S>
158 void item(const std::string &n)
162 coll.add<S>(n, it.get());
166 template<typename, typename, bool> friend class ItemKeyword;
170 typedef std::map<std::string, ItemBase *> ItemMap;
171 typedef std::list<ItemKeywordBase *> ItemKeywordSeq;
172 typedef std::list<ItemCreatorBase *> ItemCreatorSeq;
175 ItemKeywordSeq keywords;
176 ItemCreatorSeq creators;
178 Collection(const Collection &);
179 Collection &operator=(const Collection &);
182 virtual ~Collection();
185 Adds an object into the collection. If a name collision occurs, an
186 exception is thrown. The collection takes ownership of the object.
189 void add(const std::string &name, T *d)
191 if(items.count(name))
192 throw KeyError("Duplicate key '"+name+"' in collection");
194 items[name]=new Item<typename RemoveConst<T>::Type>(d);
198 Gets an object of a specific type from the collection.
201 T &get(const std::string &name) const
203 typedef typename RemoveConst<T>::Type NCT;
205 ItemMap::const_iterator i=items.find(name);
207 throw KeyError("Item '"+name+"' not found in collection");
209 const Item<NCT> *item=dynamic_cast<const Item<NCT> *>(i->second);
211 throw TypeError("Item '"+name+"' is not of correct type");
217 Gets an object of a specific type from the collection. If the name is not
218 found in the collection and there is a creator for the item type, it is
222 T &get(const std::string &name)
224 typedef typename RemoveConst<T>::Type NCT;
226 ItemMap::const_iterator i=items.find(name);
229 for(ItemCreatorSeq::iterator j=creators.begin(); j!=creators.end(); ++j)
230 if(NCT *d=(*j)->create<NCT>(*this, name))
232 // We already know that the item didn't exist yet
233 items[name]=new Item<NCT>(d);
236 throw KeyError("Item '"+name+"' not found in collection");
239 const Item<NCT> *item=dynamic_cast<const Item<NCT> *>(i->second);
241 throw TypeError("Item '"+name+"' is not of correct type");
247 Returns a list of the names of objects of a specific type in the collection.
250 std::list<std::string> get_names() const
252 std::list<std::string> result;
253 for(ItemMap::const_iterator i=items.begin(); i!=items.end(); ++i)
254 if(dynamic_cast<const Item<T> *>(i->second))
255 result.push_back(i->first);
260 Checks whether a name exists in the collection. Does not care about the
263 bool contains(const std::string &n) const;
267 Adds a type that can be loaded from datafiles.
270 void add_keyword(const std::string &keyword)
271 { add_keyword<T, T>(keyword); }
274 Adds a type that can be loaded from datafiles, with different storage type.
276 template<typename T, typename S>
277 void add_keyword(const std::string &keyword)
278 { keywords.push_back(new ItemKeyword<T, S>(keyword)); }
281 Adds a type that can be created automatically.
283 template<typename T, typename C>
284 void add_creator(T *(C::*func)(const std::string &))
285 { add_creator<T, T, C>(func); }
287 template<typename T, typename S, typename C>
288 void add_creator(T *(C::*func)(const std::string &))
289 { creators.push_back(new ItemCreator<T, S, C>(func)); }
292 } // namespace DataFile