X-Git-Url: http://git.tdb.fi/?p=libs%2Fdatafile.git;a=blobdiff_plain;f=source%2Fcollection.h;h=5dd2fe67ff2769083532605e2b33bd5fe3c9dec1;hp=0bbc9fc34203aa10c8aa4d9ddec467fddd24ea78;hb=b48d1eb90c63e70b03519923dab5e123b11d91a4;hpb=256f7238bc60d6dcc31a564988f5cc02a60c4537 diff --git a/source/collection.h b/source/collection.h index 0bbc9fc..5dd2fe6 100644 --- a/source/collection.h +++ b/source/collection.h @@ -1,13 +1,7 @@ -/* $Id$ - -This file is part of libmspdatafile -Copyright © 2006-2008 Mikko Rasa, Mikkosoft Productions -Distributed under the LGPL -*/ - #ifndef MSP_DATAFILE_COLLECTION_H_ #define MSP_DATAFILE_COLLECTION_H_ +#include #include #include #include "loader.h" @@ -29,113 +23,37 @@ struct NeedsCollection template static No f(...); - enum { result=(sizeof(f(0))==sizeof(Yes)) }; + enum { value = (sizeof(f(0))==sizeof(Yes)) }; }; +class CollectionItemTypeBase; + +template +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. */ 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 - 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 ~ItemKeywordBase() { } - virtual void add_to_loader(Loader &) const { }; - }; - - template::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); } - }; - - template - struct ItemKeyword: 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); } - }; - /** - Used to store types that can be created automatically. - */ - struct ItemCreatorBase - { - virtual ~ItemCreatorBase() { } - - template - bool create(Collection &coll, const std::string &name, S *&ptr) - { - ItemCreatorBridge *creator=dynamic_cast *>(this); - if(creator) - { - ptr=creator->create(coll, name); - return true; - } - return false; - } - }; - - template - struct ItemCreatorBridge: public ItemCreatorBase - { - virtual S *create(Collection &, const std::string &) const =0; - }; - - template - struct ItemCreator: public ItemCreatorBridge - { - 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(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 friend class CollectionItemType; + private: + template::value> + struct Add; + Collection &coll; public: @@ -145,7 +63,7 @@ public: template void coll_item(const std::string &n) { - RefPtr it=new T; + RefPtr it = new T; load_sub(*it, dynamic_cast(coll)); coll.add(n, it.get()); it.release(); @@ -154,23 +72,19 @@ public: template void item(const std::string &n) { - RefPtr it=new T; + RefPtr it = new T; load_sub(*it); coll.add(n, it.get()); it.release(); } - - template friend class ItemKeyword; }; private: - typedef std::map ItemMap; - typedef std::list ItemKeywordSeq; - typedef std::list ItemCreatorSeq; + typedef std::map ItemMap; + typedef std::list TypeList; + TypeList types; ItemMap items; - ItemKeywordSeq keywords; - ItemCreatorSeq creators; Collection(const Collection &); Collection &operator=(const Collection &); @@ -178,148 +92,289 @@ public: 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 - void add(const std::string &name, T *d) + void add(const std::string &name, T *item) { - if(items.count(name)) - throw KeyError("Duplicate key in collection", name); + if(!item) + throw std::invalid_argument("Collection::add(item)"); - items[name]=new Item::Type>(d); + RefPtr::Type> ptr(item); + try + { + insert_unique(items, name, ptr); + } + catch(...) + { + // Avoid deleting the object + ptr.release(); + throw; + } } - /** - Gets an object of a specific type from the collection. - */ + /// Gets a typed object from the collection. template - T *get(const std::string &name) const + T &get(const std::string &name) const { typedef typename RemoveConst::Type NCT; - ItemMap::const_iterator i=items.find(name); - if(i==items.end()) - throw KeyError("Item not found in collection", name); - - const Item *item=dynamic_cast *>(i->second); - if(!item) - throw TypeError("Type mismatch on item '"+name+"'"); - - return item->data; + return *get_item(items, name).value >(); } - /** - 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 - T *get(const std::string &name) - { - typedef typename RemoveConst::Type NCT; - - ItemMap::const_iterator i=items.find(name); - if(i==items.end()) - { - for(ItemCreatorSeq::iterator j=creators.begin(); j!=creators.end(); ++j) - { - NCT *d=0; - if((*j)->create(*this, name, d)) - { - // We already know that the item didn't exist yet - items[name]=new Item(d); - return d; - } - } - throw KeyError("Item not found in collection", name); - } - - const Item *item=dynamic_cast *>(i->second); - if(!item) - throw TypeError("Type mismatch on item '"+name+"'"); + T &get(const std::string &); - return item->data; - } - - /** - Returns a list of the names of objects of a specific type in the collection. - */ + /// Returns a list of the names of objects of one type in the collection. template std::list get_names() const { std::list result; for(ItemMap::const_iterator i=items.begin(); i!=items.end(); ++i) - if(dynamic_cast::Type> *>(i->second)) + if(i->second.check_type::Type> >()) result.push_back(i->first); return result; } - /** - Returns a list of objects of a specific type in the collection. - */ + /// Returns a list of objects of one type in the collection. template std::list get_list() const { - typedef typename RemoveConst::Type NCT; + typedef RefPtr::Type> RPNCT; std::list result; for(ItemMap::const_iterator i=items.begin(); i!=items.end(); ++i) - if(Item *item=dynamic_cast *>(i->second)) - result.push_back(item->data); + if(i->second.check_type()) + result.push_back(i->second.value().get()); return result; } - /** - Checks whether a name exists in the collection. Does not care about the - type of the object. - */ + /** Checks whether a name exists in the collection. Does not care about the + type of the object. */ bool contains(const std::string &n) const; - /** - Returns the name of an item in the collection. - */ + /// Returns the name of an item in the collection. template const std::string &get_name(T *d) const { - typedef typename RemoveConst::Type NCT; + typedef RefPtr::Type> RPNCT; for(ItemMap::const_iterator i=items.begin(); i!=items.end(); ++i) - if(Item *item=dynamic_cast *>(i->second)) - if(item->data==d) + if(i->second.check_type()) + if(i->second.value().get()==d) return i->first; - throw KeyError("Item not found in collection"); + // 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 - void add_keyword(const std::string &keyword) - { add_keyword(keyword); } + CollectionItemType &add_type(); +}; - /** - Adds a type that can be loaded from datafiles, with different storage type. - */ - template - void add_keyword(const std::string &keyword) - { keywords.push_back(new ItemKeyword(keyword)); } - /** - Adds a type that can be created automatically. - */ - template - void add_creator(T *(C::*func)(const std::string &)) - { add_creator(func); } +template +struct Collection::Loader::Add +{ + static void add(Loader &loader, const std::string &kwd) + { loader.add(kwd, &Loader::item); } +}; + +template +struct Collection::Loader::Add +{ + static void add(Loader &loader, const std::string &kwd) + { loader.add(kwd, &Loader::coll_item); } +}; + + +class CollectionItemTypeBase +{ +protected: + class TagBase + { + protected: + TagBase() { } + public: + virtual ~TagBase() { } + }; + + template + class Tag: public TagBase + { + public: + virtual ~Tag() { } + }; + + std::string kwd; + TagBase *tag; + + CollectionItemTypeBase(): tag(0) { } +public: + virtual ~CollectionItemTypeBase() + { delete tag; } + + 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 + bool check_type() const + { return dynamic_cast *>(tag); } +}; + + +/** +Describes a type of item that can be loaded by a Collection. These are created +by Collection::add_type. +*/ +template +class CollectionItemType: public CollectionItemTypeBase +{ +private: + class CreatorBase + { + protected: + CreatorBase() { } + public: + virtual ~CreatorBase() { } + + virtual T *create(Collection &, const std::string &) const = 0; + }; + + template + class Creator: public CreatorBase + { + public: + typedef T *(C::*FuncPtr)(const std::string &); + + private: + FuncPtr func; + + public: + Creator(FuncPtr f): func(f) { } - template - void add_creator(T *(C::*func)(const std::string &)) - { creators.push_back(new ItemCreator(func)); } + virtual T *create(Collection &coll, const std::string &name) const + { return (static_cast(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 + class Store: public StoreBase + { + public: + virtual void store(Collection &coll, const std::string &name, T *obj) + { coll.add(name, static_cast(obj)); } + + virtual void add_to_loader(Collection::Loader &loader, const std::string &kwd) + { Collection::Loader::Add::add(loader, kwd); } + }; + + CreatorBase *creat; + StoreBase *store; + +public: + CollectionItemType(): + creat(0), store(new Store) + { tag = new Tag; } + + ~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 + CollectionItemType &creator(T *(C::*func)(const std::string &)) + { + delete creat; + creat = new Creator(func); + return *this; + } + + /** Specifies the storage type for items of this type. It must be a base + class of the actual type. */ + template + CollectionItemType &store_as() + { + delete tag; + tag = new Tag; + delete store; + store = new Store; + 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 +T &Collection::get(const std::string &name) +{ + typedef typename RemoveConst::Type NCT; + + if(!items.count(name)) + { + for(TypeList::iterator i=types.begin(); i!=types.end(); ++i) + if((*i)->can_create() && (*i)->check_type()) + (*i)->create_item(*this, name); + } + + return *get_item(items, name).value >(); +} + +template +CollectionItemType &Collection::add_type() +{ + CollectionItemType *type = new CollectionItemType; + types.push_back(type); + return *type; +} + } // namespace DataFile } // namespace Msp