X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Fcollection.h;h=3d5b7f0a6abce95bc8aa5d6ec05749be3ec6f8b2;hb=8955db30f9cd1c1566b349da29e669f065f84e36;hp=3a3b90e57398ec3ff99221b09f85143a37330f02;hpb=e39534940056cdbec16c0d09d43e5375e2bbaf1c;p=libs%2Fdatafile.git

diff --git a/source/collection.h b/source/collection.h
index 3a3b90e..3d5b7f0 100644
--- a/source/collection.h
+++ b/source/collection.h
@@ -1,13 +1,8 @@
-/* $Id$
-
-This file is part of libmspdatafile
-Copyright © 2006  Mikko Rasa, Mikkosoft Productions
-Distributed under the LGPL
-*/
-
 #ifndef MSP_DATAFILE_COLLECTION_H_
 #define MSP_DATAFILE_COLLECTION_H_
 
+#include <msp/core/maputils.h>
+#include <msp/core/meta.h>
 #include <msp/core/refptr.h>
 #include "loader.h"
 
@@ -28,251 +23,471 @@ struct NeedsCollection
 	template<typename U>
 	static No f(...);
 
-	enum { result=(sizeof(f<T>(0))==sizeof(Yes)) };
+	enum { value = (sizeof(f<T>(0))==sizeof(Yes)) };
 };
 
+class CollectionItemTypeBase;
+
+template<typename T>
+class CollectionItemType;
+
 /**
 A collection of objects that can be loaded from a datafile.  Each object is
 identified by a name, which must be unique across the entire collection.
+
+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
 {
 public:
-	class Loader;
+	/**
+	Loads objects into a Collection.  Automatically picks up keywords from
+	defined item types.
+	*/
+	class Loader: public DataFile::Loader
+	{
+		template<typename T> friend class CollectionItemType;
 
-private:
-	/* XXX I don't really like sticking all this stuff in here, but there's some
-	   complex inter-class relationships, especially between ItemKeyword and
-	   Collection::Loader. */
+	private:
+		Collection &coll;
 
-	struct ItemBase
-	{
-		virtual ~ItemBase() { }
+	public:
+		Loader(Collection &);
+		Collection &get_object() const { return coll; }
+	private:
+		template<typename T, typename S>
+		void item(const std::string &n)
+		{
+			RefPtr<T> it = new T;
+			ItemLoader<T> ldr(*it, coll);
+			load_sub_with(ldr);
+			coll.add<S>(n, it.get());
+			it.release();
+		}
 	};
 
+protected:
+	template<typename T, bool = NeedsCollection<typename T::Loader>::value>
+	class ItemLoader;
+
+private:
+	typedef std::map<std::string, Variant> ItemMap;
+	typedef std::list<CollectionItemTypeBase *> TypeList;
+
+	TypeList types;
+	ItemMap items;
+
+	Collection(const Collection &);
+	Collection &operator=(const Collection &);
+public:
+	Collection() { }
+	virtual ~Collection();
+
+	/** Adds an object into the collection.  The name must not pre-exist.  The
+	collection takes ownership of the object. */
 	template<typename T>
-	struct Item: public ItemBase
+	void add(const std::string &name, T *item)
 	{
-		T *data;
+		if(!item)
+			throw std::invalid_argument("Collection::add(item)");
 
-		Item(T *d): data(d) { }
-		~Item() { delete data; }
-	};
+		typedef RefPtr<typename RemoveConst<T>::Type> RPNCT;
 
-	/**
-	Used to store keywords for types that can be loaded.
-	*/
-	struct ItemKeywordBase
+		ItemMap::iterator i = items.find(name);
+		if(i!=items.end())
+		{
+			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)
 	{
-		virtual void add_to_loader(Loader &) const { };
-	};
+		RefPtr<typename RemoveConst<T>::Type> ptr(0);
+		insert_unique(items, name, ptr);
+	}
 
-	template<typename T, typename S, bool need_coll=NeedsCollection<typename T::Loader>::result>
-	struct ItemKeyword: public ItemKeywordBase
+	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
 	{
-		std::string keyword;
+		typedef typename RemoveConst<T>::Type NCT;
 
-		ItemKeyword(const std::string &kw): keyword(kw) { }
+		T *ptr = get_item(items, name).value<RefPtr<NCT> >().get();
+		if(!ptr)
+			throw key_error(typeid(ItemMap));
+		return *ptr;
+	}
 
-		void add_to_loader(Loader &ldr) const
-		{ ldr.add(keyword, &Loader::item<T, S>); }
-	};
+	/** Gets a typed object from the collection.  If the name is not found in
+	and a creator for the item type is defined, it is invoked. */
+	template<typename T>
+	T &get(const std::string &);
 
-	template<typename T, typename S>
-	struct ItemKeyword<T, S, true>: public ItemKeywordBase
+private:
+	template<typename T>
+	void collect_items(std::list<T *> *objects, std::list<std::string> *names, std::list<std::string> *future_names) const
 	{
-		std::string keyword;
+		typedef RefPtr<typename RemoveConst<T>::Type> RPNCT;
 
-		ItemKeyword(const std::string &kw): keyword(kw) { }
+		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);
+			}
+	}
 
-		virtual void add_to_loader(Loader &ldr) const
-		{ ldr.add(keyword, &Loader::coll_item<T, S, typename T::Loader::Collection>); }
-	};
+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;
+		collect_items<T>(0, &result, 0);
+		return result;
+	}
 
-	/**
-	Used to store types that can be created automatically.
-	*/
-	struct ItemCreatorBase
+	/** 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()
 	{
-		virtual ~ItemCreatorBase() { }
+		std::list<std::string> result;
+		collect_items<T>(0, &result, &result);
+		return result;
+	}
 
-		template<typename S>
-		S *create(Collection &coll, const std::string &name)
-		{
-			ItemCreatorBridge<S> *creator=dynamic_cast<ItemCreatorBridge<S> *>(this);
-			if(creator)
-				return creator->create(coll, name);
-			return 0;
-		}
-	};
+	/// Returns a list of loaded objects of one type in the collection.
+	template<typename T>
+	std::list<T *> get_list() const
+	{
+		std::list<T *> result;
+		collect_items<T>(&result, 0, 0);
+		return result;
+	}
 
-	template<typename S>
-	struct ItemCreatorBridge: public ItemCreatorBase
+	/** 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()
 	{
-		virtual S *create(Collection &, const std::string &) const =0;
-	};
+		std::list<T *> result;
+		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;
+	}
+
+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; }
 
-	template<typename T, typename S, typename C>
-	struct ItemCreator: public ItemCreatorBridge<S>
+	/** 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>
+	const std::string &get_name(T *d) const
 	{
-		typedef T *(C::*fCreate)(const std::string &);
+		typedef RefPtr<typename RemoveConst<T>::Type> RPNCT;
+
+		for(ItemMap::const_iterator i=items.begin(); i!=items.end(); ++i)
+			if(i->second.check_type<RPNCT>())
+				if(i->second.value<RPNCT>().get()==d)
+					return i->first;
+	
+		// XXX Need better exception class
+		throw std::runtime_error("Item not found in collection");
+	}
+
+protected:
+	/** Adds a type to the collection.  The returned descriptor object reference
+	can be used to define how objects of that type can be loaded. */
+	template<typename T>
+	CollectionItemType<T> &add_type();
+};
+
+template<typename T>
+class Collection::ItemLoader<T, false>: public T::Loader
+{
+public:
+	ItemLoader(T &o, Collection &):
+		T::Loader(o)
+	{ }
+};
+
+template<typename T>
+class Collection::ItemLoader<T, true>: public T::Loader
+{
+public:
+	ItemLoader(T &o, Collection &c):
+		T::Loader(o, dynamic_cast<typename T::Loader::Collection &>(c))
+	{ }
+};
 
-		fCreate create_func;
 
-		ItemCreator(fCreate cf): create_func(cf) { }
-		virtual S *create(Collection &coll, const std::string &name) const
-		{ return (dynamic_cast<C &>(coll).*create_func)(name); }
+class CollectionItemTypeBase
+{
+protected:
+	class TagBase
+	{
+	protected:
+		TagBase() { }
+	public:
+		virtual ~TagBase() { }
 	};
 
+	template<typename T>
+	class Tag: public TagBase
+	{ };
+
+	std::string kwd;
+	std::vector<std::string> suffixes;
+	TagBase *tag;
+
+	CollectionItemTypeBase();
 public:
-	/**
-	Loads objects into a Collection.
-	*/
-	class Loader: public DataFile::Loader
+	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
+	{ return dynamic_cast<Tag<T> *>(tag); }
+};
+
+
+/**
+Describes a type of item that can be loaded by a Collection.  These are created
+by Collection::add_type.
+*/
+template<typename T>
+class CollectionItemType: public CollectionItemTypeBase
+{
+private:
+	class CreatorBase
 	{
-	private:
-		Collection &coll;
+	protected:
+		CreatorBase() { }
+	public:
+		virtual ~CreatorBase() { }
+
+		virtual T *create(Collection &, const std::string &) const = 0;
+	};
 
+	template<typename C>
+	class Creator: public CreatorBase
+	{
 	public:
-		Loader(Collection &);
-		Collection &get_object() const { return coll; }
+		typedef T *(C::*FuncPtr)(const std::string &);
+
 	private:
-		template<typename T, typename S, typename C>
-		void coll_item(const std::string &n)
-		{
-			RefPtr<T> it=new T;
-			load_sub(*it, dynamic_cast<C &>(coll));
-			coll.add<S>(n, it.get());
-			it.release();
-		}
+		FuncPtr func;
 
-		template<typename T, typename S>
-		void item(const std::string &n)
-		{
-			RefPtr<T> it=new T;
-			load_sub(*it);
-			coll.add<S>(n, it.get());
-			it.release();
-		}
+	public:
+		Creator(FuncPtr f): func(f) { }
 
-		template<typename, typename, bool> friend class ItemKeyword;
+		virtual T *create(Collection &coll, const std::string &name) const
+		{ return (static_cast<C &>(coll).*func)(name); }
 	};
 
-private:
-	typedef std::map<std::string, ItemBase *> ItemMap;
-	typedef std::list<ItemKeywordBase *> ItemKeywordSeq;
-	typedef std::list<ItemCreatorBase *> ItemCreatorSeq;
+	class StoreBase
+	{
+	protected:
+		StoreBase() { }
+	public:
+		virtual ~StoreBase() { }
 
-	ItemMap items;
-	ItemKeywordSeq keywords;
-	ItemCreatorSeq creators;
+		virtual void store(Collection &, const std::string &, T *) = 0;
+		virtual Variant create_future() const = 0;
 
-public:
-	virtual ~Collection();
+		virtual void add_to_loader(Collection::Loader &, const std::string &) = 0;
+	};
 
-	/**
-	Adds an object into the collection.  If a name collision occurs, an
-	exception is thrown.  The collection takes ownership of the object.
-	*/
-	template<typename T>
-	void add(const std::string &name, T *d)
+	template<typename S>
+	class Store: public StoreBase
 	{
-		if(items.count(name))
-			throw KeyError("Duplicate key '"+name+"' in collection");
+	public:
+		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)
+		{ loader.add(kwd, &Collection::Loader::item<T, S>); }
+	};
 
-		items[name]=new Item<T>(d);
+	CreatorBase *creat;
+	StoreBase *store;
+
+public:
+	CollectionItemType():
+		creat(0), store(new Store<T>)
+	{ tag = new Tag<T>; }
+
+	~CollectionItemType()
+	{
+		delete creat;
+		delete store;
 	}
 
-	/**
-	Gets an object of a specific type from the collection.
-	*/
-	template<typename T>
-	T &get(const std::string &name) const
+	/** Sets a datafile keyword for this item type.  The Collection's loader
+	will accept a statement with this keyword and a single string argument - the
+	item's name. */
+	CollectionItemType &keyword(const std::string &k)
 	{
-		ItemMap::const_iterator i=items.find(name);
-		if(i==items.end())
-			throw KeyError("Item '"+name+"' not found in collection");
+		set_keyword(k);
+		return *this;
+	}
 
-		const Item<T> *item=dynamic_cast<const Item<T> *>(i->second);
-		if(!item)
-			throw TypeError("Item '"+name+"' is not of correct type");
+	/** 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;
+	}
 
-		return *item->data;
+	/** Attaches a creator function to this item type.  If an item is not found
+	in the Collection, the creator function for its type is called to create it.
+	The function must be a member of the Collection subclass containing the
+	type.  It must return the created object, or null if it could not be
+	created.  It's also permissible to load the item via other means and then
+	return null. */
+	template<typename C>
+	CollectionItemType &creator(T *(C::*func)(const std::string &))
+	{
+		delete creat;
+		creat = new Creator<C>(func);
+		return *this;
 	}
 
-	/**
-	Gets an object of a specific type from the collection.  If the name is not
-	found in the collection and there is a creator for the item type, it is
-	invoked.
-	*/
-	template<typename T>
-	T &get(const std::string &name)
+	/** Specifies the storage type for items of this type.  It must be a base
+	class of the actual type.  */
+	template<typename S>
+	CollectionItemType &store_as()
 	{
-		ItemMap::const_iterator i=items.find(name);
-		if(i==items.end())
-		{
-			for(ItemCreatorSeq::iterator j=creators.begin(); j!=creators.end(); ++j)
-				if(T *d=(*j)->create<T>(*this, name))
-				{
-					// We already know that the item didn't exist yet
-					items[name]=new Item<T>(d);
-					return *d;
-				}
-			throw KeyError("Item '"+name+"' not found in collection");
-		}
+		delete tag;
+		tag = new Tag<S>;
+		delete store;
+		store = new Store<S>;
+		return *this;
+	}
 
-		const Item<T> *item=dynamic_cast<const Item<T> *>(i->second);
-		if(!item)
-			throw TypeError("Item '"+name+"' is not of correct type");
+	virtual void add_to_loader(Collection::Loader &loader) const
+	{ store->add_to_loader(loader, kwd); }
 
-		return *item->data;
-	}
+	virtual bool can_create() const
+	{ return creat!=0; }
 
-	/**
-	Returns a list of the names of objects of a specific type in the collection.
-	*/
-	template<typename T>
-	std::list<std::string> get_names() const
+	virtual void create_item(Collection &coll, const std::string &name) const
 	{
-		std::list<std::string> result;
-		for(ItemMap::const_iterator i=items.begin(); i!=items.end(); ++i)
-			if(dynamic_cast<const Item<T> *>(i->second))
-				result.push_back(i->first);
-		return result;
+		if(!creat)
+			throw std::runtime_error("no creator");
+		T *obj = creat->create(coll, name);
+		if(obj)
+			store->store(coll, name, obj);
 	}
 
-	/**
-	Checks whether a name exists in the collection.  Does not care about the
-	type of the object.
-	*/
-	bool contains(const std::string &n) const;
+	virtual Variant create_future() const
+	{ return store->create_future(); }
+};
 
-protected:
-	/**
-	Adds a type that can be loaded from datafiles.
-	*/
-	template<typename T>
-	void add_keyword(const std::string &keyword)
-	{ add_keyword<T, T>(keyword); }
 
-	/**
-	Adds a type that can be loaded from datafiles, with different storage type.
-	*/
-	template<typename T, typename S>
-	void add_keyword(const std::string &keyword)
-	{ keywords.push_back(new ItemKeyword<T, S>(keyword)); }
+template<typename T>
+T &Collection::get(const std::string &name)
+{
+	typedef typename RemoveConst<T>::Type NCT;
 
-	/**
-	Adds a type that can be created automatically.
-	*/
-	template<typename T, typename C>
-	void add_creator(T *(C::*func)(const std::string &))
-	{ add_creator<T, T, C>(func); }
+	ItemMap::iterator i = items.find(name);
+	if(i!=items.end())
+	{
+		NCT *ptr = i->second.value<RefPtr<NCT> >().get();
+		if(ptr)
+			return *ptr;
+	}
 
-	template<typename T, typename S, typename C>
-	void add_creator(T *(C::*func)(const std::string &))
-	{ creators.push_back(new ItemCreator<T, S, C>(func)); }
-};
+	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> >();
+}
+
+template<typename T>
+CollectionItemType<T> &Collection::add_type()
+{
+	CollectionItemType<T> *type = new CollectionItemType<T>;
+	types.push_back(type);
+	return *type;
+}
 
 } // namespace DataFile
 } // namespace Msp