#ifndef MSP_DATAFILE_COLLECTION_H_
#define MSP_DATAFILE_COLLECTION_H_
+#include <type_traits>
+#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. */
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
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.
+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:
/**
*/
class Loader: public DataFile::Loader
{
- template<typename T> friend class CollectionItemType;
+ template<typename T> friend class LoadableCollectionItemType;
private:
- template<typename T, typename S, bool = NeedsCollection<typename T::Loader>::value>
- struct Add;
-
Collection &coll;
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();
- }
-
template<typename T, typename S>
void item(const std::string &n)
{
RefPtr<T> it = new T;
- load_sub(*it);
+ 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;
- TypeList types;
+ std::vector<CollectionItemTypeBase *> types;
ItemMap items;
+ std::vector<const CollectionSource *> 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
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())
+ typedef typename std::remove_cv<T>::type NCT;
+ RefPtr<NCT> ptr(item);
+ try
{
- 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));
+ add_var(name, get_type<NCT>(name), ptr);
+ }
+ catch(...)
+ {
+ // Avoid deleting the object
+ ptr.release();
+ throw;
}
-
- items.insert(ItemMap::value_type(name, RPNCT(item)));
}
-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. */
+ /// Gets a typed object from the collection.
template<typename T>
- void add_future(const std::string &name)
+ T &get(const std::string &name) const
{
- RefPtr<typename RemoveConst<T>::Type> ptr(0);
- insert_unique(items, name, ptr);
+ return extract<typename std::remove_cv<T>::type>(get_item(items, name));
}
- void add_future(const std::string &name);
-
-public:
- /// Gets a typed object from the collection.
+ /** 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) const
+ T &get(const std::string &name)
{
- typedef typename RemoveConst<T>::Type NCT;
+ typedef typename std::remove_cv<T>::type NCT;
+ return extract<NCT>(get_var(name, get_type<NCT>(name)));
+ }
- T *ptr = get_item(items, name).value<RefPtr<NCT> >();
- if(!ptr)
- throw key_error(typeid(ItemMap));
- return *ptr;
+ /** 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 std::remove_cv<T>::type>(i->second) : 0);
}
- /** 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 &);
+ T *find(const std::string &name)
+ {
+ typedef typename std::remove_cv<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>
- void collect_items(std::list<T *> *objects, std::list<std::string> *names, std::list<std::string> *future_names)
- {
- typedef RefPtr<typename RemoveConst<T>::Type> RPNCT;
-
- 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)
- {
- if(objects)
- objects->push_back(ptr);
- if(names)
- names->push_back(i->first);
- }
- else if(future_names)
- future_names->push_back(i->first);
- }
+ T &extract(const Variant &var) const;
+
+ template<typename T>
+ std::list<T *> extract_list(const std::vector<const Variant *> &vars) const
+ {
+ std::list<T *> result;
+ for(const Variant *v: vars)
+ result.push_back(&extract<T>(*v));
+ return result;
+ }
+
+ void gather_items(std::vector<const Variant *> *, std::list<std::string> *, const CollectionItemTypeBase &, bool) const;
+
+ template<typename T>
+ 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);
+ else
+ gather_items(vars, names, CollectionItemType<T>(), false);
}
public:
- /** Returns a list of the names of loaded objects of one type in the
- collection. */
+ /// Returns a list of the names of objects of one type in the collection.
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 std::remove_cv<T>::type>(0, &names, 0, false);
+ return names;
}
- /** Returns a list of the names of objects of one type in the collection,
- including any future objects. */
+ /** 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> result;
- collect_items<T>(0, &result, &result);
- return result;
+ std::list<std::string> names;
+ gather_items<typename std::remove_cv<T>::type>(0, &names, 0, true);
+ return names;
}
- /// Returns a list of loaded objects of one type in the collection.
+ /// 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 std::remove_cv<T>::type>(&vars, 0, 0, false);
+ return extract_list<T>(vars);
}
- /** Returns a list of objects of one type in the collection. Any future
- objects of that type are loaded and returned in the list. */
+ /** Returns a list of objects of one type, loading them from sources if
+ necessary. */
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 std::remove_cv<T>::type>();
+ if(type)
+ load_items_from_sources(*type);
+
+ std::vector<const Variant *> vars;
+ gather_items<typename std::remove_cv<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())
- return false;
-
- typedef RefPtr<typename RemoveConst<T>::Type> RPNCT;
- if(!i->second.check_type<RPNCT>())
- return false;
+ // XXX Should go through all applicable types
+ if(CollectionItemTypeBase *type = get_type<T>())
+ return get_status(name, *type);
- T *ptr = i->second.value<RPNCT>().get();
- return ptr ? 1 : 2;
+ ItemMap::const_iterator i = items.find(name);
+ return (i!=items.end() && i->second.check_type<RefPtr<T> >());
}
public:
- /// Checks whether a typed object exists and is loaded in the collection.
+ /// 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 std::remove_cv<T>::type>(name)==1; }
- /** Checks whether a typed object exists in the collection, as either a
- loaded or future object. */
+ /** 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 std::remove_cv<T>::type>(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;
+ typedef RefPtr<typename std::remove_cv<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;
+ for(const auto &kvp: items)
+ if(kvp.second.check_type<RPNCT>())
+ if(kvp.second.value<RPNCT>().get()==d)
+ return kvp.first;
// XXX Need better exception class
throw std::runtime_error("Item not found in collection");
/** 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. An
+ optional name can be given to prioritize matching types. */
+ template<typename T>
+ 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 &);
+
+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, typename S>
-struct Collection::Loader::Add<T, S, false>
+template<typename T>
+class Collection::ItemLoader<T, false>: public T::Loader
{
- static void add(Loader &loader, const std::string &kwd)
- { loader.add(kwd, &Loader::item<T, S>); }
+public:
+ ItemLoader(T &o, Collection &):
+ T::Loader(o)
+ { }
};
-template<typename T, typename S>
-struct Collection::Loader::Add<T, S, true>
+template<typename T>
+class Collection::ItemLoader<T, true>: public T::Loader
{
- static void add(Loader &loader, const std::string &kwd)
- { loader.add(kwd, &Loader::coll_item<T, S, typename T::Loader::Collection>); }
+public:
+ ItemLoader(T &o, Collection &c):
+ T::Loader(o, dynamic_cast<typename T::Loader::Collection &>(c))
+ { }
};
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 &);
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;
- bool match_name(const std::string &) const;
- virtual Variant create_future() 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 check_type() const
- { return dynamic_cast<Tag<T> *>(tag); }
+ bool can_extract() const
+ {
+ for(ExtractorBase *e: extractors)
+ if(dynamic_cast<Extractor<T> *>(e))
+ return true;
+ return false;
+ }
+
+ template<typename T>
+ T *extract(const Variant &var) const
+ {
+ for(ExtractorBase *e: extractors)
+ if(Extractor<T> *ex = dynamic_cast<Extractor<T> *>(e))
+ return &ex->extract(var);
+ return 0;
+ }
};
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 ~NotifyeeBase() { }
- virtual void store(Collection &, const std::string &, T *) = 0;
- virtual Variant create_future() const = 0;
-
- 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 &);
- virtual Variant create_future() const
- { return RefPtr<S>(0); }
+ FuncPtr func;
- virtual void add_to_loader(Collection::Loader &loader, const std::string &kwd)
- { Collection::Loader::Add<T, S>::add(loader, kwd); }
+ Notifyee(FuncPtr f): func(f) { }
+
+ virtual void notify(Collection &coll, const std::string &name, T &item) const
+ { (dynamic_cast<C &>(coll).*func)(name, item); }
+ };
+
+ 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(NotifyeeBase *n: notif)
+ delete n;
}
/** Sets a datafile keyword for this item type. The Collection's loader
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. */
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 ¬ify(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; }
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 Variant create_future() const
- { return store->create_future(); }
+ virtual void notify_item(Collection &coll, const std::string &name, const Variant &var) const
+ {
+ RefPtr<T> obj = var.value<RefPtr<T> >();
+ for(NotifyeeBase *n: notif)
+ n->notify(coll, name, *obj);
+ }
};
template<typename T>
-T &Collection::get(const std::string &name)
+class LoadableCollectionItemType: public CollectionItemType<T>
{
- typedef typename RemoveConst<T>::Type NCT;
+public:
+ virtual void add_to_loader(Collection::Loader &loader) const
+ { loader.add(this->kwd, &Collection::Loader::item<T, T>); }
- ItemMap::iterator i = items.find(name);
- if(i!=items.end())
+ virtual void load_item(Collection &coll, Parser &parser, const std::string &name) const
{
- NCT *ptr = i->second.value<RefPtr<NCT> >().get();
- if(ptr)
- return *ptr;
+ RefPtr<T> obj = new T;
+ Collection::ItemLoader<T> ldr(*obj, coll);
+ ldr.load(parser);
+ coll.add(name, obj.get());
+ obj.release();
}
+};
- 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>
+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()
+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>
+typename CollectionItemTypeChooser<T>::Type &Collection::modify_type()
+{
+ for(CollectionItemTypeBase *t: types)
+ if(CollectionItemType<T> *tt = dynamic_cast<CollectionItemType<T> *>(t))
+ return *tt;
+
+ throw std::logic_error("type not found in collection");
+}
+
+template<typename T>
+CollectionItemTypeBase *Collection::get_type(const std::string &name) const
+{
+ for(CollectionItemTypeBase *t: types)
+ if(dynamic_cast<CollectionItemType<T> *>(t))
+ return t;
+ CollectionItemTypeBase *type = 0;
+ for(CollectionItemTypeBase *t: types)
+ if(t->can_extract<T>())
+ {
+ if(!name.empty() && t->match_name(name))
+ return t;
+ type = t;
+ }
+ return type;
+}
+
} // namespace DataFile
} // namespace Msp
projects / libs / datafile.git / blobdiff