From b26fbba2bf5d53554325762b8022c501b3b8c8fb Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Wed, 30 Dec 2020 18:40:48 +0200
Subject: [PATCH] Add find functions to Collection

---
 source/collection.cpp | 16 +++++++++++++---
 source/collection.h   | 19 +++++++++++++++++++
 2 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/source/collection.cpp b/source/collection.cpp
index 129c0a8..6d73063 100644
--- a/source/collection.cpp
+++ b/source/collection.cpp
@@ -17,10 +17,19 @@ Collection::~Collection()
 }
 
 const Variant &Collection::get_var(const string &name, const CollectionItemTypeBase *type)
+{
+	const Variant *var = find_var(name, type);
+	if(var)
+		return *var;
+
+	throw key_error(name);
+}
+
+const Variant *Collection::find_var(const string &name, const CollectionItemTypeBase *type)
 {
 	ItemMap::iterator i = items.find(name);
 	if(i!=items.end())
-		return i->second;
+		return &i->second;
 
 	if(type)
 	{
@@ -38,10 +47,11 @@ const Variant &Collection::get_var(const string &name, const CollectionItemTypeB
 		if(!loaded && fallback)
 			if(CollectionItemTypeBase *fb_type = fallback->get_type(*type))
 				if(fallback->get_status(name, *fb_type))
-					return fallback->get_var(name, fb_type);
+					return fallback->find_var(name, fb_type);
 	}
 
-	return get_item(items, name);
+	i = items.find(name);
+	return (i!=items.end() ? &i->second : 0);
 }
 
 void Collection::gather_items(vector<const Variant *> *vars, list<string> *names, const CollectionItemTypeBase &type, bool include_sources) const
diff --git a/source/collection.h b/source/collection.h
index d0e8a1a..87af3a2 100644
--- a/source/collection.h
+++ b/source/collection.h
@@ -135,8 +135,27 @@ public:
 		return extract<NCT>(get_var(name, get_type<NCT>(name)));
 	}
 
+	/** 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 RemoveConst<T>::Type>(i->second) : 0);
+	}
+
+	template<typename T>
+	T *find(const std::string &name)
+	{
+		typedef typename RemoveConst<T>::Type NCT;
+		const Variant *var = find_var(name, get_type<NCT>(name));
+		return (var ? &extract<NCT>(*var) : 0);
+	}
+
 private:
 	const Variant &get_var(const std::string &, const CollectionItemTypeBase *);
+	const Variant *find_var(const std::string &, const CollectionItemTypeBase *);
 
 	template<typename T>
 	T &extract(const Variant &var) const;
-- 
2.43.0