From: Mikko Rasa <tdb@tdb.fi>
Date: Fri, 7 Jun 2019 17:27:17 +0000 (+0300)
Subject: Allow modifying existing types in a collection
X-Git-Url: http://git.tdb.fi/?p=libs%2Fdatafile.git;a=commitdiff_plain;h=7f49649f70becbb4345ad0b936c5e00194d9dc82

Allow modifying existing types in a collection
---

diff --git a/source/collection.h b/source/collection.h
index bc84d62..005abd0 100644
--- a/source/collection.h
+++ b/source/collection.h
@@ -237,6 +237,11 @@ protected:
 	template<typename T>
 	CollectionItemType<T> &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>
+	CollectionItemType<T> &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. */
@@ -488,6 +493,16 @@ CollectionItemType<T> &Collection::add_type()
 	return *type;
 }
 
+template<typename T>
+CollectionItemType<T> &Collection::modify_type()
+{
+	for(TypeList::const_iterator j=types.begin(); j!=types.end(); ++j)
+		if(CollectionItemType<T> *t = dynamic_cast<CollectionItemType<T> *>(*j))
+			return *t;
+
+	throw std::logic_error("type not found in collection");
+}
+
 template<typename T>
 CollectionItemTypeBase *Collection::get_type(const std::string &name) const
 {