Add RAII backref context switch

Author: plafosse

demangler/msvc/demangle_msvc.cpp

@@ -111,6 +111,26 @@ void Demangle::BackrefList::PushTemplateSpecialization(const DemangledTypeNode&
 }
 
 
+Demangle::BackrefContextSwitch::BackrefContextSwitch(BackrefList& active): active(active)
+{
+	Swap(active, saved);
+}
+
+
+Demangle::BackrefContextSwitch::~BackrefContextSwitch()
+{
+	Swap(active, saved);
+}
+
+
+void Demangle::BackrefContextSwitch::Swap(BackrefList& left, BackrefList& right)
+{
+	std::swap(left.typeList, right.typeList);
+	std::swap(left.nameList, right.nameList);
+	std::swap(left.templateList, right.templateList);
+}
+
+
 
 Demangle::Demangle(Architecture* arch, const string& mangledName) :
 	m_mangledName(mangledName),
@@ -1206,33 +1226,17 @@ DemangledTypeNode Demangle::DemangleTemplateInstantiationNameInLocalContext(Back
 	vector<DemangledTypeNode::Param> params;
 	BNNameType dummyFunctionType = NoNameType;
 	NameList dummyNameList;
-	BackrefList outerBackrefs;
 	bool backrefEligible = true;
 	MSVC_TRACE("DemangleTemplateInstantiationNameInLocalContext: '%s'\n", reader.GetRaw());
 
-	std::swap(outerBackrefs.typeList, nameBackrefList.typeList);
-	std::swap(outerBackrefs.nameList, nameBackrefList.nameList);
-	std::swap(outerBackrefs.templateList, nameBackrefList.templateList);
-
-	try
 	{
+		BackrefContextSwitch localContext(nameBackrefList);
 		reader.Consume(2);
 		out = DemangleUnqualifiedSymbolName(dummyNameList, nameBackrefList, dummyFunctionType, backrefEligible);
 		if (backrefEligible && dummyFunctionType == NoNameType)
 			nameBackrefList.PushNameBackref(out);
 		DemangleTemplateParams(params, nameBackrefList, out);
 	}
-	catch (...)
-	{
-		std::swap(outerBackrefs.typeList, nameBackrefList.typeList);
-		std::swap(outerBackrefs.nameList, nameBackrefList.nameList);
-		std::swap(outerBackrefs.templateList, nameBackrefList.templateList);
-		throw;
-	}
-
-	std::swap(outerBackrefs.typeList, nameBackrefList.typeList);
-	std::swap(outerBackrefs.nameList, nameBackrefList.nameList);
-	std::swap(outerBackrefs.templateList, nameBackrefList.templateList);
 
 	nameBackrefList.PushTemplateSpecialization(out);
 	nameBackrefList.PushNameBackref(out);

demangler/msvc/demangle_msvc.h

@@ -173,6 +173,19 @@ class Demangle
 		void PushTemplateSpecialization(const DemangledTypeNode& t);
 	};
 
+	struct BackrefContextSwitch
+	{
+		BackrefList& active;
+		BackrefList saved;
+
+		BackrefContextSwitch(BackrefList& active);
+		BackrefContextSwitch(const BackrefContextSwitch&) = delete;
+		BackrefContextSwitch& operator=(const BackrefContextSwitch&) = delete;
+		~BackrefContextSwitch();
+
+		static void Swap(BackrefList& left, BackrefList& right);
+	};
+
 	// Internal name list type - keeps template names structured during parsing.
 	typedef _STD_VECTOR<DemangledTypeNode> NameList;