-/* $Id$
-
-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"
template<typename U>
static No f(...);
- enum { result=(sizeof(f<T>(0))==sizeof(Yes)) };
+ enum { value = (sizeof(f<T>(0))==sizeof(Yes)) };
};
-template<typename T>
-struct RemoveConst
-{ typedef T Type; };
+class CollectionItemTypeBase;
template<typename T>
-struct RemoveConst<const T>
-{ typedef T Type; };
+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;
-
-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. */
-
- struct ItemBase
- {
- virtual ~ItemBase() { }
- };
-
- template<typename T>
- struct Item: public ItemBase
- {
- T *data;
-
- Item(T *d): data(d) { }
- ~Item() { delete data; }
- };
-
/**
- Used to store keywords for types that can be loaded.
- */
- struct ItemKeywordBase
- {
- virtual void add_to_loader(Loader &) const { };
- };
-
- template<typename T, typename S, bool need_coll=NeedsCollection<typename T::Loader>::result>
- struct ItemKeyword: public ItemKeywordBase
- {
- std::string keyword;
-
- ItemKeyword(const std::string &kw): keyword(kw) { }
-
- void add_to_loader(Loader &ldr) const
- { ldr.add(keyword, &Loader::item<T, S>); }
- };
-
- template<typename T, typename S>
- struct ItemKeyword<T, S, true>: public ItemKeywordBase
- {
- std::string keyword;
-
- ItemKeyword(const std::string &kw): keyword(kw) { }
-
- virtual void add_to_loader(Loader &ldr) const
- { ldr.add(keyword, &Loader::coll_item<T, S, typename T::Loader::Collection>); }
- };
-
- /**
- Used to store types that can be created automatically.
- */
- struct ItemCreatorBase
- {
- virtual ~ItemCreatorBase() { }
-
- 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;
- }
- };
-
- template<typename S>
- struct ItemCreatorBridge: public ItemCreatorBase
- {
- virtual S *create(Collection &, const std::string &) const =0;
- };
-
- template<typename T, typename S, typename C>
- struct ItemCreator: public ItemCreatorBridge<S>
- {
- typedef T *(C::*fCreate)(const std::string &);
-
- 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); }
- };
-
-public:
- /**
- Loads objects into a Collection.
+ 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:
+ template<typename T, typename S, bool = NeedsCollection<typename T::Loader>::value>
+ struct Add;
+
Collection &coll;
public:
template<typename T, typename S, typename C>
void coll_item(const std::string &n)
{
- RefPtr<T> it=new T;
+ RefPtr<T> it = new T;
load_sub(*it, dynamic_cast<C &>(coll));
coll.add<S>(n, it.get());
it.release();
template<typename T, typename S>
void item(const std::string &n)
{
- RefPtr<T> it=new T;
+ RefPtr<T> it = new T;
load_sub(*it);
coll.add<S>(n, it.get());
it.release();
}
-
- template<typename, typename, bool> friend class ItemKeyword;
};
private:
- typedef std::map<std::string, ItemBase *> ItemMap;
- typedef std::list<ItemKeywordBase *> ItemKeywordSeq;
- typedef std::list<ItemCreatorBase *> ItemCreatorSeq;
+ typedef std::map<std::string, Variant> ItemMap;
+ typedef std::list<CollectionItemTypeBase *> TypeList;
+ TypeList types;
ItemMap items;
- ItemKeywordSeq keywords;
- ItemCreatorSeq creators;
Collection(const Collection &);
Collection &operator=(const Collection &);
Collection() { }
virtual ~Collection();
- /**
- Adds an object into the collection. If a name collision occurs, an
- exception is thrown. The collection takes ownership of the object.
- */
+ /** Adds an object into the collection. The name must not pre-exist. The
+ collection takes ownership of the object. */
template<typename T>
- void add(const std::string &name, T *d)
+ void add(const std::string &name, T *item)
{
- if(items.count(name))
- throw KeyError("Duplicate key '"+name+"' in collection");
+ if(!item)
+ throw std::invalid_argument("Collection::add(item)");
+
+ typedef RefPtr<typename RemoveConst<T>::Type> RPNCT;
+
+ 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[name]=new Item<typename RemoveConst<T>::Type>(d);
+ items.insert(ItemMap::value_type(name, RPNCT(item)));
}
- /**
- Gets an object of a specific type from the collection.
- */
+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)
+ {
+ RefPtr<typename RemoveConst<T>::Type> ptr(0);
+ insert_unique(items, name, ptr);
+ }
+
+public:
+ /// Gets a typed object from the collection.
template<typename T>
T &get(const std::string &name) const
{
typedef typename RemoveConst<T>::Type NCT;
- ItemMap::const_iterator i=items.find(name);
- if(i==items.end())
- throw KeyError("Item '"+name+"' not found in collection");
-
- const Item<NCT> *item=dynamic_cast<const Item<NCT> *>(i->second);
- if(!item)
- throw TypeError("Item '"+name+"' is not of correct type");
-
- return *item->data;
+ T *ptr = get_item(items, name).value<RefPtr<NCT> >();
+ if(!ptr)
+ throw key_error(typeid(ItemMap));
+ return *ptr;
}
- /**
- 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.
- */
+ /** 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 &);
+
+private:
template<typename T>
- T &get(const std::string &name)
+ void collect_items(std::list<T *> *objects, std::list<std::string> *names, std::list<std::string> *future_names)
{
- typedef typename RemoveConst<T>::Type NCT;
+ typedef RefPtr<typename RemoveConst<T>::Type> RPNCT;
- ItemMap::const_iterator i=items.find(name);
- if(i==items.end())
- {
- for(ItemCreatorSeq::iterator j=creators.begin(); j!=creators.end(); ++j)
- if(NCT *d=(*j)->create<NCT>(*this, name))
+ 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)
{
- // We already know that the item didn't exist yet
- items[name]=new Item<NCT>(d);
- return *d;
+ if(objects)
+ objects->push_back(ptr);
+ if(names)
+ names->push_back(i->first);
}
- throw KeyError("Item '"+name+"' not found in collection");
- }
-
- const Item<NCT> *item=dynamic_cast<const Item<NCT> *>(i->second);
- if(!item)
- throw TypeError("Item '"+name+"' is not of correct type");
-
- return *item->data;
+ else if(future_names)
+ future_names->push_back(i->first);
+ }
}
- /**
- Returns a list of the names of objects of a specific type in the 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;
- for(ItemMap::const_iterator i=items.begin(); i!=items.end(); ++i)
- if(dynamic_cast<const Item<typename RemoveConst<T>::Type> *>(i->second))
- result.push_back(i->first);
+ collect_items<T>(0, &result, 0);
return result;
}
- /**
- Returns a list of objects of a specific type in the collection.
- */
+ /** 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()
+ {
+ std::list<std::string> result;
+ collect_items<T>(0, &result, &result);
+ return result;
+ }
+
+ /// Returns a list of loaded objects of one type in the collection.
template<typename T>
std::list<T *> get_list() const
{
- typedef typename RemoveConst<T>::Type NCT;
+ std::list<T *> result;
+ collect_items<T>(&result, 0, 0);
+ return result;
+ }
+ /** 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()
+ {
std::list<T *> result;
- for(ItemMap::const_iterator i=items.begin(); i!=items.end(); ++i)
- if(Item<NCT> *item=dynamic_cast<Item<NCT> *>(i->second))
- result.push_back(item->data);
+ 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;
}
- /**
- Checks whether a name exists in the collection. Does not care about the
- type of the object.
- */
- bool contains(const std::string &n) const;
+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; }
+
+ /** 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 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 that can be loaded from datafiles.
- */
+ /** 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>
- void add_keyword(const std::string &keyword)
- { add_keyword<T, T>(keyword); }
+ CollectionItemType<T> &add_type();
+};
- /**
- 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)); }
- /**
- 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); }
+template<typename T, typename S>
+struct Collection::Loader::Add<T, S, false>
+{
+ static void add(Loader &loader, const std::string &kwd)
+ { loader.add(kwd, &Loader::item<T, S>); }
+};
- 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)); }
+template<typename T, typename S>
+struct Collection::Loader::Add<T, S, true>
+{
+ static void add(Loader &loader, const std::string &kwd)
+ { loader.add(kwd, &Loader::coll_item<T, S, typename T::Loader::Collection>); }
};
+
+class CollectionItemTypeBase
+{
+protected:
+ class TagBase
+ {
+ protected:
+ TagBase() { }
+ public:
+ virtual ~TagBase() { }
+ };
+
+ template<typename T>
+ class Tag: public TagBase
+ { };
+
+ std::string kwd;
+ TagBase *tag;
+
+ CollectionItemTypeBase();
+public:
+ virtual ~CollectionItemTypeBase();
+
+ 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;
+
+ 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
+ {
+ protected:
+ CreatorBase() { }
+ public:
+ virtual ~CreatorBase() { }
+
+ virtual T *create(Collection &, const std::string &) const = 0;
+ };
+
+ template<typename C>
+ class Creator: public 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); }
+ };
+
+ class StoreBase
+ {
+ protected:
+ StoreBase() { }
+ public:
+ virtual ~StoreBase() { }
+
+ virtual void store(Collection &, const std::string &, T *) = 0;
+
+ virtual void add_to_loader(Collection::Loader &, const std::string &) = 0;
+ };
+
+ template<typename S>
+ class Store: public StoreBase
+ {
+ public:
+ virtual void store(Collection &coll, const std::string &name, T *obj)
+ { coll.add(name, static_cast<S *>(obj)); }
+
+ virtual void add_to_loader(Collection::Loader &loader, const std::string &kwd)
+ { Collection::Loader::Add<T, S>::add(loader, kwd); }
+ };
+
+ CreatorBase *creat;
+ StoreBase *store;
+
+public:
+ CollectionItemType():
+ creat(0), store(new Store<T>)
+ { tag = new Tag<T>; }
+
+ ~CollectionItemType()
+ {
+ delete creat;
+ delete store;
+ }
+
+ /** 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)
+ {
+ kwd = k;
+ return *this;
+ }
+
+ /** 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;
+ }
+
+ /** 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()
+ {
+ delete tag;
+ tag = new Tag<S>;
+ delete store;
+ store = new Store<S>;
+ return *this;
+ }
+
+ virtual void add_to_loader(Collection::Loader &loader) const
+ { store->add_to_loader(loader, kwd); }
+
+ virtual bool can_create() const
+ { return creat!=0; }
+
+ virtual void create_item(Collection &coll, const std::string &name) const
+ {
+ if(!creat)
+ throw std::runtime_error("no creator");
+ T *obj = creat->create(coll, name);
+ if(obj)
+ store->store(coll, name, obj);
+ }
+};
+
+
+template<typename T>
+T &Collection::get(const std::string &name)
+{
+ typedef typename RemoveConst<T>::Type NCT;
+
+ ItemMap::iterator i = items.find(name);
+ if(i!=items.end())
+ {
+ NCT *ptr = i->second.value<RefPtr<NCT> >().get();
+ if(ptr)
+ return *ptr;
+ }
+
+ 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
projects / libs / datafile.git / blobdiff