X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Fcollection.h;h=a7ac59bc8069b19697fab896826ef499b3a84e8d;hb=07d4c0e55aa9571c9f24cf39d134f1f7474fd7cb;hp=ee7eb469cf53d5ee1ab8d9cd06a0b88688511b06;hpb=a5d5fa04bcbe360fc55fdb25b45937b29fb5c9cd;p=libs%2Fdatafile.git diff --git a/source/collection.h b/source/collection.h index ee7eb46..a7ac59b 100644 --- a/source/collection.h +++ b/source/collection.h @@ -17,17 +17,14 @@ namespace DataFile { Helper struct to determine whether a Loader has a Collection typedef. */ template -struct NeedsCollection +struct NeedsCollection: public Sfinae { - struct Yes { char c[2]; }; - struct No { char c; }; - template static Yes f(typename U::Collection *); template static No f(...); - enum { value = (sizeof(f(0))==sizeof(Yes)) }; + enum { value = Evaluate(0))>::value }; }; class CollectionItemTypeBase; @@ -46,8 +43,8 @@ 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. -A fallback collection can be designated as another way of loading items that -are not present. Items retrieted from the fallback collection are shared +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. */ @@ -262,8 +259,15 @@ private: 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(CollectionSource &); + /** 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_from_sources(const std::string &); + private: void gather_names_from_sources(std::list &, const CollectionItemTypeBase &) const;