X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Fcollection.h;h=aa3c18a0fcc1a5e27f5d4ddc1278b58e65904877;hb=fbf76ed98dbd2cca6785efe2dd489d717fa5dce6;hp=be9ae88c491595f925db46e30aeff2daa67deb5f;hpb=698d4ae13da87b7c53aa96bca99c3deaff397eec;p=libs%2Fdatafile.git

diff --git a/source/collection.h b/source/collection.h
index be9ae88..aa3c18a 100644
--- a/source/collection.h
+++ b/source/collection.h
@@ -1,11 +1,13 @@
 #ifndef MSP_DATAFILE_COLLECTION_H_
 #define MSP_DATAFILE_COLLECTION_H_
 
+#include <msp/core/attributes.h>
 #include <msp/core/maputils.h>
-#include <msp/core/meta.h>
+#include <msp/core/noncopyable.h>
 #include <msp/core/refptr.h>
 #include "collectionsource.h"
 #include "loader.h"
+#include "meta.h"
 
 /* XXX This file is a big mess with too many things in it.  However, the
 dependencies between those things make it difficult to split up. */
@@ -13,27 +15,24 @@ dependencies between those things make it difficult to split up. */
 namespace Msp {
 namespace DataFile {
 
-/**
-Helper struct to determine whether a Loader has a Collection typedef.
-*/
+class CollectionItemTypeBase;
+
 template<typename T>
-struct NeedsCollection
-{
-	struct Yes { char c[2]; };
-	struct No { char c; };
+class CollectionItemType;
 
-	template<typename U>
-	static Yes f(typename U::Collection *);
-	template<typename U>
-	static No f(...);
+template<typename T>
+class LoadableCollectionItemType;
 
-	enum { value = (sizeof(f<T>(0))==sizeof(Yes)) };
-};
+template<typename T, bool = HasLoader<T>::value>
+struct CollectionItemTypeChooser;
 
-class CollectionItemTypeBase;
+template<typename T>
+struct CollectionItemTypeChooser<T, true>
+{ typedef LoadableCollectionItemType<T> Type; };
 
 template<typename T>
-class CollectionItemType;
+struct CollectionItemTypeChooser<T, false>
+{ typedef CollectionItemType<T> Type; };
 
 /**
 A collection of objects that can be loaded from a datafile.  Each object is
@@ -45,8 +44,13 @@ method for details.
 
 Collections can have sources for loading objects on demand.  Automatic loading
 only works on a non-const Collection.  See class CollectionSource for details.
+
+As a last resort, a fallback collection can be designated for loading items
+that are not present.  Items retrieted from the fallback collection are shared
+between the collections, and are only deleted when all collections in the chain
+have been destroyed.
 */
-class Collection
+class Collection: private NonCopyable
 {
 public:
 	/**
@@ -55,7 +59,7 @@ public:
 	*/
 	class Loader: public DataFile::Loader
 	{
-		template<typename T> friend class CollectionItemType;
+		template<typename T> friend class LoadableCollectionItemType;
 
 	private:
 		Collection &coll;
@@ -75,23 +79,21 @@ public:
 		}
 	};
 
-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;
-	typedef std::list<CollectionSource *> SourceList;
+	typedef std::vector<CollectionItemTypeBase *> TypeList;
+	typedef std::vector<const CollectionSource *> SourceList;
 
 	TypeList types;
 	ItemMap items;
 	SourceList sources;
+	Collection *fallback;
 
-	Collection(const Collection &);
-	Collection &operator=(const Collection &);
 public:
-	Collection() { }
+	Collection();
 	virtual ~Collection();
 
 	/** Adds an object into the collection.  The name must not pre-exist.  The
@@ -102,14 +104,25 @@ public:
 		if(!item)
 			throw std::invalid_argument("Collection::add(item)");
 
-		insert_unique(items, name, RefPtr<typename RemoveConst<T>::Type>(item));
+		typedef typename RemoveConst<T>::Type NCT;
+		RefPtr<NCT> ptr(item);
+		try
+		{
+			add_var(name, get_type<NCT>(name), ptr);
+		}
+		catch(...)
+		{
+			// Avoid deleting the object
+			ptr.release();
+			throw;
+		}
 	}
 
 	/// Gets a typed object from the collection.
 	template<typename T>
 	T &get(const std::string &name) const
 	{
-		return extract<T>(get_item(items, name));
+		return extract<typename RemoveConst<T>::Type>(get_item(items, name));
 	}
 
 	/** Gets a typed object from the collection.  If the name is not found,
@@ -118,43 +131,54 @@ public:
 	template<typename T>
 	T &get(const std::string &name)
 	{
-		return extract<T>(get_var(name, get_type<T>()));
+		typedef typename RemoveConst<T>::Type NCT;
+		return extract<NCT>(get_var(name, get_type<NCT>(name)));
+	}
+
+	/** Finds a typed object in the collection.  Returns null if the name does
+	not exist.  Throws if the name exists but the object is of an incorrect
+	type. */
+	template<typename T>
+	T *find(const std::string &name) const
+	{
+		ItemMap::const_iterator i = items.find(name);
+		return (i!=items.end() ? extract<typename RemoveConst<T>::Type>(i->second) : 0);
+	}
+
+	template<typename T>
+	T *find(const std::string &name)
+	{
+		typedef typename RemoveConst<T>::Type NCT;
+		const Variant *var = find_var(name, get_type<NCT>(name));
+		return (var ? &extract<NCT>(*var) : 0);
 	}
 
 private:
+	void add_var(const std::string &, const CollectionItemTypeBase *, const Variant &);
 	const Variant &get_var(const std::string &, const CollectionItemTypeBase *);
+	const Variant *find_var(const std::string &, const CollectionItemTypeBase *);
+
+	template<typename T>
+	T &extract(const Variant &var) const;
 
 	template<typename T>
-	T &extract(const Variant &var) const
+	std::list<T *> extract_list(const std::vector<const Variant *> &vars) const
 	{
-		return *var.value<RefPtr<typename RemoveConst<T>::Type> >();
+		std::list<T *> result;
+		for(std::vector<const Variant *>::const_iterator i=vars.begin(); i!=vars.end(); ++i)
+			result.push_back(&extract<T>(**i));
+		return result;
 	}
 
+	void gather_items(std::vector<const Variant *> *, std::list<std::string> *, const CollectionItemTypeBase &, bool) const;
+
 	template<typename T>
-	void collect_items(std::list<T *> *objects, std::list<std::string> *names, std::list<std::string> *future_names) const
+	void gather_items(std::vector<const Variant *> *vars, std::list<std::string> *names, const CollectionItemTypeBase *type, bool include_sources) 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>())
-			{
-				if(objects)
-					objects->push_back(i->second.value<RPNCT>().get());
-				if(names)
-					names->push_back(i->first);
-			}
-
-		if(future_names)
-			if(CollectionItemTypeBase *type = get_type<T>())
-			{
-				for(SourceList::const_iterator i=sources.begin(); i!=sources.end(); ++i)
-				{
-					std::list<std::string> available_names = (*i)->get_names(*type);
-					for(std::list<std::string>::iterator j=available_names.begin(); j!=available_names.end(); ++j)
-						if(!items.count(*j))
-							future_names->push_back(*j);
-				}
-			}
+		if(type || (type = get_type<T>()))
+			gather_items(vars, names, *type, include_sources);
+		else
+			gather_items(vars, names, CollectionItemType<T>(), false);
 	}
 
 public:
@@ -162,9 +186,9 @@ public:
 	template<typename T>
 	std::list<std::string> get_names() const
 	{
-		std::list<std::string> result;
-		collect_items<T>(0, &result, 0);
-		return result;
+		std::list<std::string> names;
+		gather_items<typename RemoveConst<T>::Type>(0, &names, 0, false);
+		return names;
 	}
 
 	/** Returns a list of the names of objects of one type in the collection or
@@ -172,18 +196,18 @@ public:
 	template<typename T>
 	std::list<std::string> get_names()
 	{
-		std::list<std::string> result;
-		collect_items<T>(0, &result, &result);
-		return result;
+		std::list<std::string> names;
+		gather_items<typename RemoveConst<T>::Type>(0, &names, 0, true);
+		return names;
 	}
 
 	/// Returns a list of 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;
+		std::vector<const Variant *> vars;
+		gather_items<typename RemoveConst<T>::Type>(&vars, 0, 0, false);
+		return extract_list<T>(vars);
 	}
 
 	/** Returns a list of objects of one type, loading them from sources if
@@ -191,48 +215,40 @@ public:
 	template<typename T>
 	std::list<T *> get_list()
 	{
-		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;
+		CollectionItemTypeBase *type = get_type<typename RemoveConst<T>::Type>();
+		if(type)
+			load_items_from_sources(*type);
+
+		std::vector<const Variant *> vars;
+		gather_items<typename RemoveConst<T>::Type>(&vars, 0, type, true);
+		return extract_list<T>(vars);
 	}
 
 private:
+	unsigned get_status(const std::string &, const CollectionItemTypeBase &) const;
+
 	template<typename T>
 	unsigned get_status(const std::string &name) const
 	{
-		ItemMap::const_iterator i = items.find(name);
-		if(i==items.end())
-		{
-			if(CollectionItemTypeBase *type = get_type<T>())
-			{
-				for(SourceList::const_iterator j=sources.begin(); j!=sources.end(); ++j)
-					if((*j)->is_loadable(*type, name))
-						return 2;
-			}
-			return 0;
-		}
-
-		typedef RefPtr<typename RemoveConst<T>::Type> RPNCT;
-		if(!i->second.check_type<RPNCT>())
-			return 0;
+		// XXX Should go through all applicable types
+		if(CollectionItemTypeBase *type = get_type<T>())
+			return get_status(name, *type);
 
-		return 1;
+		ItemMap::const_iterator i = items.find(name);
+		return (i!=items.end() && i->second.check_type<RefPtr<T> >());
 	}
 
 public:
 	/// Checks whether a typed object exists in the collection.
 	template<typename T>
 	bool contains(const std::string &name) const
-	{ return get_status<T>(name)==1; }
+	{ return get_status<typename RemoveConst<T>::Type>(name)==1; }
 
 	/** Checks whether a typed object exists in the collection or is loadable
 	from a source. */
 	template<typename T>
 	bool contains(const std::string &name)
-	{ return get_status<T>(name)>0; }
+	{ return get_status<typename RemoveConst<T>::Type>(name)>0; }
 
 	/// Returns the name of an item in the collection.
 	template<typename T>
@@ -253,13 +269,47 @@ 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();
+	typename CollectionItemTypeChooser<T>::Type &add_type();
+
+	/** Returns a mutable reference to an existing type descriptor.  This can be
+	used to e.g. override the creator function of a type added by a base class. */
+	template<typename T>
+	typename CollectionItemTypeChooser<T>::Type &modify_type();
 
-	/** Returns the descriptor for a type, or null if one isn't defined. */
+private:
+	/** Returns the descriptor for a type, or null if one isn't defined.  An
+	optional name can be given to prioritize matching types. */
 	template<typename T>
-	CollectionItemTypeBase *get_type() const;
+	CollectionItemTypeBase *get_type(const std::string & = std::string()) const;
+
+	/// Gets a descriptor with the same type as another descriptor.
+	CollectionItemTypeBase *get_type(const CollectionItemTypeBase &) const;
+
+	/// Returns the descriptor for an item, or null if it's of an unknown type.
+	CollectionItemTypeBase *get_type_for_item(const Variant &) const;
+
+protected:
+	/** Adds a source for automatically loading items.  Sources are consulted
+	in the order they are added. */
+	void add_source(const CollectionSource &);
 
-	void add_source(CollectionSource &);
+public:
+	/** Opens a raw resource, without interpreting it as object data.  Null is
+	returned if no such file is found.  The caller must dispose of the returned
+	object when done with it. */
+	IO::Seekable *open_raw(const std::string &) const;
+
+private:
+	void gather_names_from_sources(std::list<std::string> &, const CollectionItemTypeBase &) const;
+
+	void load_items_from_sources(const CollectionItemTypeBase &);
+
+protected:
+	/** Sets a fallback collection, which will be consulted if an item is not
+	found. */
+	void set_fallback(Collection *);
+
+	Collection *get_fallback() const { return fallback; }
 };
 
 template<typename T>
@@ -284,38 +334,56 @@ public:
 class CollectionItemTypeBase
 {
 protected:
-	class TagBase
+	struct ExtractorBase
 	{
-	protected:
-		TagBase() { }
-	public:
-		virtual ~TagBase() { }
+		virtual ~ExtractorBase() { }
 	};
 
 	template<typename T>
-	class Tag: public TagBase
-	{ };
+	struct Extractor: ExtractorBase
+	{
+		virtual T &extract(const Variant &) const = 0;
+	};
 
 	std::string kwd;
 	std::vector<std::string> suffixes;
-	TagBase *tag;
+	std::vector<ExtractorBase *> extractors;
 
-	CollectionItemTypeBase();
+	CollectionItemTypeBase() { }
 public:
 	virtual ~CollectionItemTypeBase();
 
+protected:
 	void set_keyword(const std::string &);
-	const std::string &get_keyword() const { return kwd; }
 	void add_suffix(const std::string &);
+public:
+	const std::string &get_keyword() const { return kwd; }
 	bool match_name(const std::string &) const;
+	virtual bool is_same_type(const CollectionItemTypeBase &) const = 0;
+	virtual bool check_item_type(const Variant &) const = 0;
 	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;
 	virtual void load_item(Collection &, Parser &, const std::string &) const = 0;
+	virtual void notify_item(Collection &, const std::string &, const Variant &) const = 0;
+
+	template<typename T>
+	bool can_extract() const
+	{
+		for(std::vector<ExtractorBase *>::const_iterator i=extractors.begin(); i!=extractors.end(); ++i)
+			if(dynamic_cast<Extractor<T> *>(*i))
+				return true;
+		return false;
+	}
 
 	template<typename T>
-	bool check_type() const
-	{ return dynamic_cast<Tag<T> *>(tag); }
+	T *extract(const Variant &var) const
+	{
+		for(std::vector<ExtractorBase *>::const_iterator i=extractors.begin(); i!=extractors.end(); ++i)
+			if(Extractor<T> *ex = dynamic_cast<Extractor<T> *>(*i))
+				return &ex->extract(var);
+		return 0;
+	}
 };
 
 
@@ -327,67 +395,66 @@ template<typename T>
 class CollectionItemType: public CollectionItemTypeBase
 {
 private:
-	class CreatorBase
+	struct CreatorBase
 	{
-	protected:
-		CreatorBase() { }
-	public:
 		virtual ~CreatorBase() { }
 
 		virtual T *create(Collection &, const std::string &) const = 0;
 	};
 
 	template<typename C>
-	class Creator: public CreatorBase
+	struct Creator: CreatorBase
 	{
-	public:
 		typedef T *(C::*FuncPtr)(const std::string &);
 
-	private:
 		FuncPtr func;
 
-	public:
 		Creator(FuncPtr f): func(f) { }
 
 		virtual T *create(Collection &coll, const std::string &name) const
-		{ return (static_cast<C &>(coll).*func)(name); }
+		{ return (dynamic_cast<C &>(coll).*func)(name); }
 	};
 
-	class StoreBase
+	struct NotifyeeBase
 	{
-	protected:
-		StoreBase() { }
-	public:
-		virtual ~StoreBase() { }
-
-		virtual void store(Collection &, const std::string &, T *) = 0;
+		virtual ~NotifyeeBase() { }
 
-		virtual void add_to_loader(Collection::Loader &, const std::string &) = 0;
+		virtual void notify(Collection &, const std::string &, T &) const = 0;
 	};
 
-	template<typename S>
-	class Store: public StoreBase
+	template<typename C>
+	struct Notifyee: NotifyeeBase
 	{
-	public:
-		virtual void store(Collection &coll, const std::string &name, T *obj)
-		{ coll.add(name, static_cast<S *>(obj)); }
+		typedef void (C::*FuncPtr)(const std::string &, T &);
+
+		FuncPtr func;
+
+		Notifyee(FuncPtr f): func(f) { }
+
+		virtual void notify(Collection &coll, const std::string &name, T &item) const
+		{ (dynamic_cast<C &>(coll).*func)(name, item); }
+	};
 
-		virtual void add_to_loader(Collection::Loader &loader, const std::string &kwd)
-		{ loader.add(kwd, &Collection::Loader::item<T, S>); }
+	template<typename B>
+	struct Extractor: CollectionItemTypeBase::Extractor<B>
+	{
+		virtual B &extract(const Variant &var) const
+		{ return *var.value<RefPtr<T> >(); }
 	};
 
 	CreatorBase *creat;
-	StoreBase *store;
+	std::vector<NotifyeeBase *> notif;
 
 public:
 	CollectionItemType():
-		creat(0), store(new Store<T>)
-	{ tag = new Tag<T>; }
+		creat(0)
+	{ }
 
 	~CollectionItemType()
 	{
 		delete creat;
-		delete store;
+		for(typename std::vector<NotifyeeBase *>::const_iterator i=notif.begin(); i!=notif.end(); ++i)
+			delete *i;
 	}
 
 	/** Sets a datafile keyword for this item type.  The Collection's loader
@@ -399,7 +466,7 @@ public:
 		return *this;
 	}
 
-	/** Adds a suffix that is used to match names when looking for future
+	/** Adds a suffix that is used to match names when looking for loadable
 	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. */
@@ -423,20 +490,29 @@ public:
 		return *this;
 	}
 
-	/** 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()
+	/** Makes items of this type available through a base class. */
+	template<typename B>
+	CollectionItemType &base()
 	{
-		delete tag;
-		tag = new Tag<S>;
-		delete store;
-		store = new Store<S>;
+		extractors.push_back(new Extractor<B>);
 		return *this;
 	}
 
-	virtual void add_to_loader(Collection::Loader &loader) const
-	{ store->add_to_loader(loader, kwd); }
+	template<typename C>
+	CollectionItemType &notify(void (C::*func)(const std::string &, T &))
+	{
+		notif.push_back(new Notifyee<C>(func));
+		return *this;
+	}
+
+	virtual bool is_same_type(const CollectionItemTypeBase &other) const
+	{ return dynamic_cast<const CollectionItemType<T> *>(&other); }
+
+	virtual bool check_item_type(const Variant &var) const
+	{ return var.check_type<RefPtr<T> >(); }
+
+	virtual void add_to_loader(Collection::Loader &) const
+	{ }
 
 	virtual bool can_create() const
 	{ return creat!=0; }
@@ -447,35 +523,85 @@ public:
 			throw std::runtime_error("no creator");
 		T *obj = creat->create(coll, name);
 		if(obj)
-			store->store(coll, name, obj);
+			coll.add(name, obj);
+	}
+
+	virtual void load_item(Collection &, Parser &, const std::string &) const
+	{
+		throw std::runtime_error("this type cannot be loaded");
+	}
+
+	virtual void notify_item(Collection &coll, const std::string &name, const Variant &var) const
+	{
+		RefPtr<T> obj = var.value<RefPtr<T> >();
+		for(typename std::vector<NotifyeeBase *>::const_iterator i=notif.begin(); i!=notif.end(); ++i)
+			(*i)->notify(coll, name, *obj);
 	}
+};
+
+
+template<typename T>
+class LoadableCollectionItemType: public CollectionItemType<T>
+{
+public:
+	virtual void add_to_loader(Collection::Loader &loader) const
+	{ loader.add(this->kwd, &Collection::Loader::item<T, T>); }
 
 	virtual void load_item(Collection &coll, Parser &parser, const std::string &name) const
 	{
 		RefPtr<T> obj = new T;
 		Collection::ItemLoader<T> ldr(*obj, coll);
 		ldr.load(parser);
-		store->store(coll, name, obj.get());
+		coll.add(name, obj.get());
 		obj.release();
 	}
 };
 
 
 template<typename T>
-CollectionItemType<T> &Collection::add_type()
+T &Collection::extract(const Variant &var) const
+{
+	if(!var.check_type<RefPtr<T> >())
+		if(CollectionItemTypeBase *type = get_type_for_item(var))
+			if(T *item = type->extract<T>(var))
+				return *item;
+
+	return *var.value<RefPtr<T> >();
+}
+
+template<typename T>
+typename CollectionItemTypeChooser<T>::Type &Collection::add_type()
 {
-	CollectionItemType<T> *type = new CollectionItemType<T>;
+	typename CollectionItemTypeChooser<T>::Type *type = new typename CollectionItemTypeChooser<T>::Type;
 	types.push_back(type);
 	return *type;
 }
 
 template<typename T>
-CollectionItemTypeBase *Collection::get_type() const
+typename CollectionItemTypeChooser<T>::Type &Collection::modify_type()
 {
 	for(TypeList::const_iterator j=types.begin(); j!=types.end(); ++j)
-		if((*j)->check_type<typename RemoveConst<T>::Type>())
+		if(CollectionItemType<T> *t = dynamic_cast<CollectionItemType<T> *>(*j))
+			return *t;
+
+	throw std::logic_error("type not found in collection");
+}
+
+template<typename T>
+CollectionItemTypeBase *Collection::get_type(const std::string &name) const
+{
+	for(TypeList::const_iterator j=types.begin(); j!=types.end(); ++j)
+		if(dynamic_cast<CollectionItemType<T> *>(*j))
 			return *j;
-	return 0;
+	CollectionItemTypeBase *type = 0;
+	for(TypeList::const_iterator j=types.begin(); j!=types.end(); ++j)
+		if((*j)->can_extract<T>())
+		{
+			if(!name.empty() && (*j)->match_name(name))
+				return *j;
+			type = *j;
+		}
+	return type;
 }
 
 } // namespace DataFile