X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Fcollection.h;h=0cd799abf060e399a20c55027371917e14f563c5;hb=f19f861eb6858f396d574f0d45c5e967221a384b;hp=612a0af01879deaac213f1883db29df76d3cd57d;hpb=5e677b2b3eeb2b3c41216a329f7b1363aade0aed;p=libs%2Fdatafile.git

diff --git a/source/collection.h b/source/collection.h
index 612a0af..0cd799a 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. */
@@ -13,24 +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: public Sfinae
-{
-	template<typename U>
-	static Yes f(typename U::Collection *);
-	template<typename U>
-	static No f(...);
+class CollectionItemType;
 
-	enum { value = Evaluate<sizeof(f<T>(0))>::value };
-};
+template<typename T>
+class LoadableCollectionItemType;
 
-class CollectionItemTypeBase;
+template<typename T, bool = HasLoader<T>::value>
+struct CollectionItemTypeChooser;
 
 template<typename T>
-class CollectionItemType;
+struct CollectionItemTypeChooser<T, true>
+{ typedef LoadableCollectionItemType<T> Type; };
+
+template<typename T>
+struct CollectionItemTypeChooser<T, false>
+{ typedef CollectionItemType<T> Type; };
 
 /**
 A collection of objects that can be loaded from a datafile.  Each object is
@@ -48,7 +50,7 @@ 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:
 	/**
@@ -57,7 +59,7 @@ public:
 	*/
 	class Loader: public DataFile::Loader
 	{
-		template<typename T> friend class CollectionItemType;
+		template<typename T> friend class LoadableCollectionItemType;
 
 	private:
 		Collection &coll;
@@ -82,16 +84,14 @@ public:
 
 private:
 	typedef std::map<std::string, Variant> ItemMap;
-	typedef std::list<CollectionItemTypeBase *> TypeList;
-	typedef std::list<const 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();
 	virtual ~Collection();
@@ -131,28 +131,47 @@ public:
 	T &get(const std::string &name)
 	{
 		typedef typename RemoveConst<T>::Type NCT;
-		return extract<NCT>(get_var(name, get_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:
 	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>
-	std::list<T *> extract_list(const std::list<const Variant *> &vars) const
+	std::list<T *> extract_list(const std::vector<const Variant *> &vars) const
 	{
 		std::list<T *> result;
-		for(std::list<const Variant *>::const_iterator i=vars.begin(); i!=vars.end(); ++i)
+		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::list<const Variant *> *, std::list<std::string> *, const CollectionItemTypeBase &, bool) const;
+	void gather_items(std::vector<const Variant *> *, std::list<std::string> *, const CollectionItemTypeBase &, bool) const;
 
 	template<typename T>
-	void gather_items(std::list<const Variant *> *vars, std::list<std::string> *names, const CollectionItemTypeBase *type, bool include_sources) const
+	void gather_items(std::vector<const Variant *> *vars, std::list<std::string> *names, const CollectionItemTypeBase *type, bool include_sources) const
 	{
 		if(type || (type = get_type<T>()))
 			gather_items(vars, names, *type, include_sources);
@@ -184,7 +203,7 @@ public:
 	template<typename T>
 	std::list<T *> get_list() const
 	{
-		std::list<const Variant *> vars;
+		std::vector<const Variant *> vars;
 		gather_items<typename RemoveConst<T>::Type>(&vars, 0, 0, false);
 		return extract_list<T>(vars);
 	}
@@ -198,7 +217,7 @@ public:
 		if(type)
 			load_items_from_sources(*type);
 
-		std::list<const Variant *> vars;
+		std::vector<const Variant *> vars;
 		gather_items<typename RemoveConst<T>::Type>(&vars, 0, type, true);
 		return extract_list<T>(vars);
 	}
@@ -248,12 +267,18 @@ 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();
 
 private:
-	/// Returns the descriptor for a type, or null if one isn't defined.
+	/** 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;
@@ -272,9 +297,6 @@ public:
 	object when done with it. */
 	IO::Seekable *open_raw(const std::string &) const;
 
-protected:
-	IO::Seekable *open_from_sources(const std::string &n) { return open_raw(n); }
-
 private:
 	void gather_names_from_sources(std::list<std::string> &, const CollectionItemTypeBase &) const;
 
@@ -284,6 +306,8 @@ 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>
@@ -327,9 +351,11 @@ protected:
 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;
@@ -414,7 +440,7 @@ 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. */
@@ -452,8 +478,8 @@ public:
 	virtual bool check_item_type(const Variant &var) const
 	{ return var.check_type<RefPtr<T> >(); }
 
-	virtual void add_to_loader(Collection::Loader &loader) const
-	{ loader.add(kwd, &Collection::Loader::item<T, T>); }
+	virtual void add_to_loader(Collection::Loader &) const
+	{ }
 
 	virtual bool can_create() const
 	{ return creat!=0; }
@@ -467,6 +493,20 @@ public:
 			coll.add(name, obj);
 	}
 
+	virtual void load_item(Collection &, Parser &, const std::string &) const
+	{
+		throw std::runtime_error("this type cannot be loaded");
+	}
+};
+
+
+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;
@@ -490,23 +530,38 @@ T &Collection::extract(const Variant &var) const
 }
 
 template<typename T>
-CollectionItemType<T> &Collection::add_type()
+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(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;
+	CollectionItemTypeBase *type = 0;
 	for(TypeList::const_iterator j=types.begin(); j!=types.end(); ++j)
 		if((*j)->can_extract<T>())
-			return *j;
-	return 0;
+		{
+			if(!name.empty() && (*j)->match_name(name))
+				return *j;
+			type = *j;
+		}
+	return type;
 }
 
 } // namespace DataFile