1 #ifndef MSP_DATAFILE_COLLECTION_H_
2 #define MSP_DATAFILE_COLLECTION_H_
5 #include <msp/core/attributes.h>
6 #include <msp/core/maputils.h>
7 #include <msp/core/noncopyable.h>
8 #include <msp/core/refptr.h>
9 #include "collectionsource.h"
13 /* XXX This file is a big mess with too many things in it. However, the
14 dependencies between those things make it difficult to split up. */
19 class CollectionItemTypeBase;
22 class CollectionItemType;
25 class LoadableCollectionItemType;
27 template<typename T, bool = HasLoader<T>::value>
28 struct CollectionItemTypeChooser;
31 struct CollectionItemTypeChooser<T, true>
32 { typedef LoadableCollectionItemType<T> Type; };
35 struct CollectionItemTypeChooser<T, false>
36 { typedef CollectionItemType<T> Type; };
39 A collection of objects that can be loaded from a datafile. Each object is
40 identified by a name, which must be unique across the entire collection.
42 While this class can be instantiated by itself and used for storing objects,
43 loading requires that a subclass defines the supported types. See the add_type
46 Collections can have sources for loading objects on demand. Automatic loading
47 only works on a non-const Collection. See class CollectionSource for details.
49 As a last resort, a fallback collection can be designated for loading items
50 that are not present. Items retrieted from the fallback collection are shared
51 between the collections, and are only deleted when all collections in the chain
54 class Collection: private NonCopyable
58 Loads objects into a Collection. Automatically picks up keywords from
61 class Loader: public DataFile::Loader
63 template<typename T> friend class LoadableCollectionItemType;
70 Collection &get_object() const { return coll; }
72 template<typename T, typename S>
73 void item(const std::string &n)
76 ItemLoader<T> ldr(*it, coll);
78 coll.add<S>(n, it.get());
83 template<typename T, bool = NeedsCollection<typename T::Loader>::value>
87 typedef std::map<std::string, Variant> ItemMap;
89 std::vector<CollectionItemTypeBase *> types;
91 std::vector<const CollectionSource *> sources;
96 virtual ~Collection();
98 /** Adds an object into the collection. The name must not pre-exist. The
99 collection takes ownership of the object. */
101 void add(const std::string &name, T *item)
104 throw std::invalid_argument("Collection::add(item)");
106 typedef typename std::remove_cv<T>::type NCT;
107 RefPtr<NCT> ptr(item);
110 add_var(name, get_type<NCT>(name), ptr);
114 // Avoid deleting the object
120 /// Gets a typed object from the collection.
122 T &get(const std::string &name) const
124 return extract<typename std::remove_cv<T>::type>(get_item(items, name));
127 /** Gets a typed object from the collection. If the name is not found,
128 automatic creation with the type's creator function (if defined) or from
129 sources (if present) is attempted. */
131 T &get(const std::string &name)
133 typedef typename std::remove_cv<T>::type NCT;
134 return extract<NCT>(get_var(name, get_type<NCT>(name)));
137 /** Finds a typed object in the collection. Returns null if the name does
138 not exist. Throws if the name exists but the object is of an incorrect
141 T *find(const std::string &name) const
143 ItemMap::const_iterator i = items.find(name);
144 return (i!=items.end() ? extract<typename std::remove_cv<T>::type>(i->second) : 0);
148 T *find(const std::string &name)
150 typedef typename std::remove_cv<T>::type NCT;
151 const Variant *var = find_var(name, get_type<NCT>(name));
152 return (var ? &extract<NCT>(*var) : 0);
156 void add_var(const std::string &, const CollectionItemTypeBase *, const Variant &);
157 const Variant &get_var(const std::string &, const CollectionItemTypeBase *);
158 const Variant *find_var(const std::string &, const CollectionItemTypeBase *);
161 T &extract(const Variant &var) const;
164 std::list<T *> extract_list(const std::vector<const Variant *> &vars) const
166 std::list<T *> result;
167 for(const Variant *v: vars)
168 result.push_back(&extract<T>(*v));
172 void gather_items(std::vector<const Variant *> *, std::list<std::string> *, const CollectionItemTypeBase &, bool) const;
175 void gather_items(std::vector<const Variant *> *vars, std::list<std::string> *names, const CollectionItemTypeBase *type, bool include_sources) const
177 if(type || (type = get_type<T>()))
178 gather_items(vars, names, *type, include_sources);
180 gather_items(vars, names, CollectionItemType<T>(), false);
184 /// Returns a list of the names of objects of one type in the collection.
186 std::list<std::string> get_names() const
188 std::list<std::string> names;
189 gather_items<typename std::remove_cv<T>::type>(0, &names, 0, false);
193 /** Returns a list of the names of objects of one type in the collection or
194 available from sources. */
196 std::list<std::string> get_names()
198 std::list<std::string> names;
199 gather_items<typename std::remove_cv<T>::type>(0, &names, 0, true);
203 /// Returns a list of objects of one type in the collection.
205 std::list<T *> get_list() const
207 std::vector<const Variant *> vars;
208 gather_items<typename std::remove_cv<T>::type>(&vars, 0, 0, false);
209 return extract_list<T>(vars);
212 /** Returns a list of objects of one type, loading them from sources if
215 std::list<T *> get_list()
217 CollectionItemTypeBase *type = get_type<typename std::remove_cv<T>::type>();
219 load_items_from_sources(*type);
221 std::vector<const Variant *> vars;
222 gather_items<typename std::remove_cv<T>::type>(&vars, 0, type, true);
223 return extract_list<T>(vars);
227 unsigned get_status(const std::string &, const CollectionItemTypeBase &) const;
230 unsigned get_status(const std::string &name) const
232 // XXX Should go through all applicable types
233 if(CollectionItemTypeBase *type = get_type<T>())
234 return get_status(name, *type);
236 ItemMap::const_iterator i = items.find(name);
237 return (i!=items.end() && i->second.check_type<RefPtr<T> >());
241 /// Checks whether a typed object exists in the collection.
243 bool contains(const std::string &name) const
244 { return get_status<typename std::remove_cv<T>::type>(name)==1; }
246 /** Checks whether a typed object exists in the collection or is loadable
249 bool contains(const std::string &name)
250 { return get_status<typename std::remove_cv<T>::type>(name)>0; }
252 /// Returns the name of an item in the collection.
254 const std::string &get_name(T *d) const
256 typedef RefPtr<typename std::remove_cv<T>::type> RPNCT;
258 for(const auto &kvp: items)
259 if(kvp.second.check_type<RPNCT>())
260 if(kvp.second.value<RPNCT>().get()==d)
263 // XXX Need better exception class
264 throw std::runtime_error("Item not found in collection");
268 /** Adds a type to the collection. The returned descriptor object reference
269 can be used to define how objects of that type can be loaded. */
271 typename CollectionItemTypeChooser<T>::Type &add_type();
273 /** Returns a mutable reference to an existing type descriptor. This can be
274 used to e.g. override the creator function of a type added by a base class. */
276 typename CollectionItemTypeChooser<T>::Type &modify_type();
279 /** Returns the descriptor for a type, or null if one isn't defined. An
280 optional name can be given to prioritize matching types. */
282 CollectionItemTypeBase *get_type(const std::string & = std::string()) const;
284 /// Gets a descriptor with the same type as another descriptor.
285 CollectionItemTypeBase *get_type(const CollectionItemTypeBase &) const;
287 /// Returns the descriptor for an item, or null if it's of an unknown type.
288 CollectionItemTypeBase *get_type_for_item(const Variant &) const;
291 /** Adds a source for automatically loading items. Sources are consulted
292 in the order they are added. */
293 void add_source(const CollectionSource &);
296 /** Opens a raw resource, without interpreting it as object data. Null is
297 returned if no such file is found. The caller must dispose of the returned
298 object when done with it. */
299 IO::Seekable *open_raw(const std::string &) const;
302 void gather_names_from_sources(std::list<std::string> &, const CollectionItemTypeBase &) const;
304 void load_items_from_sources(const CollectionItemTypeBase &);
307 /** Sets a fallback collection, which will be consulted if an item is not
309 void set_fallback(Collection *);
311 Collection *get_fallback() const { return fallback; }
315 class Collection::ItemLoader<T, false>: public T::Loader
318 ItemLoader(T &o, Collection &):
324 class Collection::ItemLoader<T, true>: public T::Loader
327 ItemLoader(T &o, Collection &c):
328 T::Loader(o, dynamic_cast<typename T::Loader::Collection &>(c))
333 class CollectionItemTypeBase
338 virtual ~ExtractorBase() { }
342 struct Extractor: ExtractorBase
344 virtual T &extract(const Variant &) const = 0;
348 std::vector<std::string> suffixes;
349 std::vector<ExtractorBase *> extractors;
351 CollectionItemTypeBase() { }
353 virtual ~CollectionItemTypeBase();
356 void set_keyword(const std::string &);
357 void add_suffix(const std::string &);
359 const std::string &get_keyword() const { return kwd; }
360 bool match_name(const std::string &) const;
361 virtual bool is_same_type(const CollectionItemTypeBase &) const = 0;
362 virtual bool check_item_type(const Variant &) const = 0;
363 virtual void add_to_loader(Collection::Loader &) const = 0;
364 virtual bool can_create() const = 0;
365 virtual void create_item(Collection &, const std::string &) const = 0;
366 virtual void load_item(Collection &, Parser &, const std::string &) const = 0;
367 virtual void notify_item(const std::string &, const Variant &) const = 0;
370 bool can_extract() const
372 for(ExtractorBase *e: extractors)
373 if(dynamic_cast<Extractor<T> *>(e))
379 T *extract(const Variant &var) const
381 for(ExtractorBase *e: extractors)
382 if(Extractor<T> *ex = dynamic_cast<Extractor<T> *>(e))
383 return &ex->extract(var);
390 Describes a type of item that can be loaded by a Collection. These are created
391 by Collection::add_type.
394 class CollectionItemType: public CollectionItemTypeBase
398 struct Extractor: CollectionItemTypeBase::Extractor<B>
400 virtual B &extract(const Variant &var) const
401 { return *var.value<RefPtr<T> >(); }
404 std::function<T *(const std::string &)> create_func;
405 std::vector<std::function<void(const std::string &, T &)>> notify_funcs;
408 /** Sets a datafile keyword for this item type. The Collection's loader
409 will accept a statement with this keyword and a single string argument - the
411 CollectionItemType &keyword(const std::string &k)
417 /** Adds a suffix that is used to match names when looking for loadable
418 objects. There is no implied separator; a name matches if it ends with the
419 suffix. If a keyword is defined before any suffixes, then "."+keyword is
420 added as a suffix. */
421 CollectionItemType &suffix(const std::string &s)
427 /** Attaches a creator function to this item type. If an item is not found
428 in the Collection, the creator function for its type is called to create it.
429 The function must be a member of the Collection subclass containing the
430 type. It must return the created object, or null if it could not be
431 created. It's also permissible to load the item via other means and then
434 CollectionItemType &creator(F func)
440 /** Makes items of this type available through a base class. */
442 CollectionItemType &base()
444 extractors.push_back(new Extractor<B>);
449 CollectionItemType ¬ify(F func)
451 notify_funcs.emplace_back(func);
455 virtual bool is_same_type(const CollectionItemTypeBase &other) const
456 { return dynamic_cast<const CollectionItemType<T> *>(&other); }
458 virtual bool check_item_type(const Variant &var) const
459 { return var.check_type<RefPtr<T> >(); }
461 virtual void add_to_loader(Collection::Loader &) const
464 virtual bool can_create() const
465 { return static_cast<bool>(create_func); }
467 virtual void create_item(Collection &coll, const std::string &name) const
470 throw std::runtime_error("no creator");
471 T *obj = create_func(name);
476 virtual void load_item(Collection &, Parser &, const std::string &) const
478 throw std::runtime_error("this type cannot be loaded");
481 virtual void notify_item(const std::string &name, const Variant &var) const
483 RefPtr<T> obj = var.value<RefPtr<T> >();
484 for(const auto &n: notify_funcs)
491 class LoadableCollectionItemType: public CollectionItemType<T>
494 virtual void add_to_loader(Collection::Loader &loader) const
495 { loader.add(this->kwd, &Collection::Loader::item<T, T>); }
497 virtual void load_item(Collection &coll, Parser &parser, const std::string &name) const
499 RefPtr<T> obj = new T;
500 Collection::ItemLoader<T> ldr(*obj, coll);
502 coll.add(name, obj.get());
509 T &Collection::extract(const Variant &var) const
511 if(!var.check_type<RefPtr<T> >())
512 if(CollectionItemTypeBase *type = get_type_for_item(var))
513 if(T *item = type->extract<T>(var))
516 return *var.value<RefPtr<T> >();
520 typename CollectionItemTypeChooser<T>::Type &Collection::add_type()
522 typename CollectionItemTypeChooser<T>::Type *type = new typename CollectionItemTypeChooser<T>::Type;
523 types.push_back(type);
528 typename CollectionItemTypeChooser<T>::Type &Collection::modify_type()
530 for(CollectionItemTypeBase *t: types)
531 if(CollectionItemType<T> *tt = dynamic_cast<CollectionItemType<T> *>(t))
534 throw std::logic_error("type not found in collection");
538 CollectionItemTypeBase *Collection::get_type(const std::string &name) const
540 for(CollectionItemTypeBase *t: types)
541 if(dynamic_cast<CollectionItemType<T> *>(t))
543 CollectionItemTypeBase *type = 0;
544 for(CollectionItemTypeBase *t: types)
545 if(t->can_extract<T>())
547 if(!name.empty() && t->match_name(name))
554 } // namespace DataFile