-/* $Id$
-
-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 "collectionsource.h"
#include "loader.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. */
+
namespace Msp {
namespace DataFile {
Helper struct to determine whether a Loader has a Collection typedef.
*/
template<typename T>
-struct NeedsCollection
+struct NeedsCollection: public Sfinae
{
- struct Yes { char c[2]; };
- struct No { char c; };
-
template<typename U>
static Yes f(typename U::Collection *);
template<typename U>
static No f(...);
- enum { result=(sizeof(f<T>(0))==sizeof(Yes)) };
+ enum { value = Evaluate<sizeof(f<T>(0))>::value };
};
-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 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
{
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();
+ }
};
+ 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<const CollectionSource *> SourceList;
+
+ TypeList types;
+ ItemMap items;
+ SourceList sources;
+ Collection *fallback;
+
+ 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; }
- };
+ RefPtr<typename RemoveConst<T>::Type> ptr(item);
+ try
+ {
+ insert_unique(items, name, ptr);
+ }
+ catch(...)
+ {
+ // Avoid deleting the object
+ ptr.release();
+ throw;
+ }
+ }
- /**
- Used to store keywords for types that can be loaded.
- */
- struct ItemKeywordBase
+ /// Gets a typed object from the collection.
+ template<typename T>
+ T &get(const std::string &name) const
{
- virtual void add_to_loader(Loader &) const { };
- };
+ return extract<typename RemoveConst<T>::Type>(get_item(items, name));
+ }
- template<typename T, typename S, bool need_coll=NeedsCollection<typename T::Loader>::result>
- struct ItemKeyword: public ItemKeywordBase
+ /** Gets a typed object from the collection. If the name is not found,
+ automatic creation with the type's creator function (if defined) or from
+ sources (if present) is attempted. */
+ template<typename T>
+ T &get(const std::string &name)
{
- std::string keyword;
+ typedef typename RemoveConst<T>::Type NCT;
+ return extract<NCT>(get_var(name, get_type<NCT>()));
+ }
- ItemKeyword(const std::string &kw): keyword(kw) { }
+private:
+ const Variant &get_var(const std::string &, const CollectionItemTypeBase *);
- void add_to_loader(Loader &ldr) const
- { ldr.add(keyword, &Loader::item<T, S>); }
- };
+ template<typename T>
+ T &extract(const Variant &var) const;
- template<typename T, typename S>
- struct ItemKeyword<T, S, true>: public ItemKeywordBase
+ template<typename T>
+ std::list<T *> extract_list(const std::list<const Variant *> &vars) const
{
- std::string keyword;
+ std::list<T *> result;
+ for(std::list<const Variant *>::const_iterator i=vars.begin(); i!=vars.end(); ++i)
+ result.push_back(&extract<T>(**i));
+ return result;
+ }
- ItemKeyword(const std::string &kw): keyword(kw) { }
+ void gather_items(std::list<const Variant *> *, std::list<std::string> *, const CollectionItemTypeBase &, bool) const;
- virtual void add_to_loader(Loader &ldr) const
- { ldr.add(keyword, &Loader::coll_item<T, S, typename T::Loader::Collection>); }
- };
+ template<typename T>
+ void gather_items(std::list<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);
+ else
+ gather_items(vars, names, CollectionItemType<T>(), false);
+ }
- /**
- Used to store types that can be created automatically.
- */
- struct ItemCreatorBase
+public:
+ /// Returns a list of the names of objects of one type in the collection.
+ template<typename T>
+ std::list<std::string> get_names() const
{
- virtual ~ItemCreatorBase() { }
+ std::list<std::string> names;
+ gather_items<typename RemoveConst<T>::Type>(0, &names, 0, false);
+ return names;
+ }
- template<typename S>
- bool create(Collection &coll, const std::string &name, S *&ptr)
- {
- ItemCreatorBridge<S> *creator=dynamic_cast<ItemCreatorBridge<S> *>(this);
- if(creator)
- {
- creator->create(coll, name, ptr);
- return true;
- }
- return false;
- }
- };
+ /** Returns a list of the names of objects of one type in the collection or
+ available from sources. */
+ template<typename T>
+ std::list<std::string> get_names()
+ {
+ std::list<std::string> names;
+ gather_items<typename RemoveConst<T>::Type>(0, &names, 0, true);
+ return names;
+ }
- template<typename S>
- struct ItemCreatorBridge: public ItemCreatorBase
+ /// Returns a list of objects of one type in the collection.
+ template<typename T>
+ std::list<T *> get_list() const
{
- virtual bool create(Collection &, const std::string &, S *&) const =0;
- };
+ std::list<const Variant *> vars;
+ gather_items<typename RemoveConst<T>::Type>(&vars, 0, 0, false);
+ return extract_list<T>(vars);
+ }
- template<typename T, typename S, typename C>
- struct ItemCreator: public ItemCreatorBridge<S>
+ /** Returns a list of objects of one type, loading them from sources if
+ necessary. */
+ template<typename T>
+ std::list<T *> get_list()
{
- typedef T *(C::*fCreate)(const std::string &);
+ CollectionItemTypeBase *type = get_type<typename RemoveConst<T>::Type>();
+ if(type)
+ load_items_from_sources(*type);
- fCreate create_func;
+ std::list<const Variant *> vars;
+ gather_items<typename RemoveConst<T>::Type>(&vars, 0, type, true);
+ return extract_list<T>(vars);
+ }
- ItemCreator(fCreate cf): create_func(cf) { }
- virtual S *create(Collection &coll, const std::string &name) const
- { return (dynamic_cast<C &>(coll).*create_func)(name); }
- };
+private:
+ unsigned get_status(const std::string &, const CollectionItemTypeBase &) const;
+
+ template<typename T>
+ unsigned get_status(const std::string &name) const
+ {
+ // XXX Should go through all applicable types
+ if(CollectionItemTypeBase *type = get_type<T>())
+ return get_status(name, *type);
+
+ ItemMap::const_iterator i = items.find(name);
+ return (i!=items.end() && i->second.check_type<RefPtr<T> >());
+ }
public:
- /**
- Loads objects into a Collection.
- */
- class Loader: public DataFile::Loader
+ /// Checks whether a typed object exists in the collection.
+ template<typename T>
+ bool contains(const std::string &name) const
+ { 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<typename RemoveConst<T>::Type>(name)>0; }
+
+ /// Returns the name of an item in the collection.
+ template<typename T>
+ const std::string &get_name(T *d) const
{
- private:
- Collection &coll;
+ typedef RefPtr<typename RemoveConst<T>::Type> RPNCT;
- public:
- Loader(Collection &);
- Collection &get_object() const { return coll; }
- 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();
- }
+ 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");
+ }
- 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();
- }
+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, typename, bool> friend class ItemKeyword;
- };
+private:
+ /// Returns the descriptor for a type, or null if one isn't defined.
+ template<typename T>
+ CollectionItemTypeBase *get_type() 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 &);
+
+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;
+
+protected:
+ IO::Seekable *open_from_sources(const std::string &n) { return open_raw(n); }
private:
- typedef std::map<std::string, ItemBase *> ItemMap;
- typedef std::list<ItemKeywordBase *> ItemKeywordSeq;
- typedef std::list<ItemCreatorBase *> ItemCreatorSeq;
+ void gather_names_from_sources(std::list<std::string> &, const CollectionItemTypeBase &) const;
- ItemMap items;
- ItemKeywordSeq keywords;
- ItemCreatorSeq creators;
+ void load_items_from_sources(const CollectionItemTypeBase &);
- Collection(const Collection &);
- Collection &operator=(const Collection &);
+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>
+class Collection::ItemLoader<T, false>: public T::Loader
+{
public:
- Collection() { }
- virtual ~Collection();
+ 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))
+ { }
+};
+
+
+class CollectionItemTypeBase
+{
+protected:
+ struct ExtractorBase
+ {
+ virtual ~ExtractorBase() { }
+ };
- /**
- 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)
+ struct Extractor: ExtractorBase
{
- if(items.count(name))
- throw KeyError("Duplicate key '"+name+"' in collection");
+ virtual T &extract(const Variant &) const = 0;
+ };
- items[name]=new Item<typename RemoveConst<T>::Type>(d);
+ std::string kwd;
+ std::vector<std::string> suffixes;
+ std::vector<ExtractorBase *> extractors;
+
+ CollectionItemTypeBase() { }
+public:
+ virtual ~CollectionItemTypeBase();
+
+ void set_keyword(const std::string &);
+ const std::string &get_keyword() const { return kwd; }
+ void add_suffix(const std::string &);
+ 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;
+
+ 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;
}
- /**
- Gets an object of a specific type from the collection.
- */
template<typename T>
- T *get(const std::string &name) const
+ T *extract(const Variant &var) const
{
- typedef typename RemoveConst<T>::Type NCT;
+ 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;
+ }
+};
- 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");
+/**
+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:
+ struct CreatorBase
+ {
+ virtual ~CreatorBase() { }
- return *item->data;
- }
+ virtual T *create(Collection &, const std::string &) const = 0;
+ };
- /**
- 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)
+ template<typename C>
+ struct Creator: CreatorBase
{
- typedef typename RemoveConst<T>::Type NCT;
+ typedef T *(C::*FuncPtr)(const std::string &);
- 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<NCT>(d);
- return *d;
- }
- }
- throw KeyError("Item '"+name+"' not found in collection");
- }
+ FuncPtr func;
- const Item<NCT> *item=dynamic_cast<const Item<NCT> *>(i->second);
- if(!item)
- throw TypeError("Item '"+name+"' is not of correct type");
+ Creator(FuncPtr f): func(f) { }
- return *item->data;
+ virtual T *create(Collection &coll, const std::string &name) const
+ { return (dynamic_cast<C &>(coll).*func)(name); }
+ };
+
+ template<typename B>
+ struct Extractor: CollectionItemTypeBase::Extractor<B>
+ {
+ virtual B &extract(const Variant &var) const
+ { return *var.value<RefPtr<T> >(); }
+ };
+
+ CreatorBase *creat;
+
+public:
+ CollectionItemType():
+ creat(0)
+ { }
+
+ ~CollectionItemType()
+ {
+ delete creat;
}
- /**
- 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
+ /** 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)
{
- 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);
- return result;
+ set_keyword(k);
+ return *this;
}
- /**
- Returns a list of objects of a specific type in the collection.
- */
- template<typename T>
- std::list<T *> get_list() const
+ /** 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)
{
- typedef typename RemoveConst<T>::Type NCT;
+ add_suffix(s);
+ return *this;
+ }
- 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);
- return result;
+ /** 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;
}
- /**
- Checks whether a name exists in the collection. Does not care about the
- type of the object.
- */
- bool contains(const std::string &n) const;
+ /** Makes items of this type available through a base class. */
+ template<typename B>
+ CollectionItemType &base()
+ {
+ extractors.push_back(new Extractor<B>);
+ return *this;
+ }
-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); }
+ virtual bool is_same_type(const CollectionItemTypeBase &other) const
+ { return dynamic_cast<const CollectionItemType<T> *>(&other); }
- /**
- 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)); }
+ virtual bool check_item_type(const Variant &var) const
+ { return var.check_type<RefPtr<T> >(); }
- /**
- 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); }
+ virtual void add_to_loader(Collection::Loader &loader) const
+ { loader.add(kwd, &Collection::Loader::item<T, T>); }
- 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)); }
+ 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)
+ coll.add(name, obj);
+ }
+
+ 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);
+ coll.add(name, obj.get());
+ obj.release();
+ }
};
+
+template<typename T>
+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>
+CollectionItemType<T> &Collection::add_type()
+{
+ CollectionItemType<T> *type = new CollectionItemType<T>;
+ types.push_back(type);
+ return *type;
+}
+
+template<typename T>
+CollectionItemTypeBase *Collection::get_type() const
+{
+ for(TypeList::const_iterator j=types.begin(); j!=types.end(); ++j)
+ if(dynamic_cast<CollectionItemType<T> *>(*j))
+ return *j;
+ for(TypeList::const_iterator j=types.begin(); j!=types.end(); ++j)
+ if((*j)->can_extract<T>())
+ return *j;
+ return 0;
+}
+
} // namespace DataFile
} // namespace Msp
projects / libs / datafile.git / blobdiff