X-Git-Url: http://git.tdb.fi/?p=libs%2Fdatafile.git;a=blobdiff_plain;f=source%2Fobjectloader.h;h=e383109f791937739c7e80e5e3d10486bc1641ff;hp=f1cb6ffe051c5f8405fa652a67d36b3001dee380;hb=HEAD;hpb=302f73123da1194dd91b43138cd880cae9318a14

diff --git a/source/objectloader.h b/source/objectloader.h
index f1cb6ff..978366f 100644
--- a/source/objectloader.h
+++ b/source/objectloader.h
@@ -1,18 +1,12 @@
 #ifndef MSP_DATAFILE_OBJECTLOADER_H_
 #define MSP_DATAFILE_OBJECTLOADER_H_
 
-#include <typeinfo>
+#include "except.h"
 #include "loader.h"
 
 namespace Msp {
 namespace DataFile {
 
-class no_collection: public std::runtime_error
-{
-public:
-	no_collection(const std::type_info &);
-};
-
 class Collection;
 
 /**
@@ -20,7 +14,7 @@ Provides the basic functionality of an object loader.  Deriving from this
 allows loading values directly into member variables of the objects.
 */
 template<typename O>
-class ObjectLoader: public Loader
+class ObjectLoader: virtual public Loader
 {
 public:
 	typedef O Object;
@@ -35,6 +29,27 @@ public:
 };
 
 
+/**
+Convenience class for loading derived objects.  Inherits from the base class
+loader and shadows its members with ones for the derived type.
+*/
+template<typename O, typename B>
+class DerivedObjectLoader: public B
+{
+public:
+	typedef O Object;
+
+protected:
+	O &obj;
+
+	template<typename... Args>
+	DerivedObjectLoader(O &o, Args &&... a): B(o, std::forward<Args>(a)...), obj(o) { }
+
+public:
+	O &get_object() const { return obj; }
+};
+
+
 /**
 Provides functionality for loading objects with a Collection.  Deriving from
 this allows loading pointers to objects in the collection automatically.
@@ -46,7 +61,7 @@ public:
 	typedef C Collection;
 
 protected:
-	C *coll;
+	C *coll = nullptr;
 
 	CollectionObjectLoader(O &o, C *c): ObjectLoader<O>(o), coll(c) { }