Implement constructor-style casts

fixes #8832

lib/base/function.cpp

@@ -23,7 +23,7 @@
 
 using namespace icinga;
 
-REGISTER_PRIMITIVE_TYPE(Function, Function::GetPrototype());
+REGISTER_PRIMITIVE_TYPE_NOINST(Function, Function::GetPrototype());
 
 Function::Function(const Callback& function)
 	: m_Callback(function)

lib/base/primitivetype.cpp

@@ -22,8 +22,8 @@
 
 using namespace icinga;
 
-PrimitiveType::PrimitiveType(const String& name)
-	: m_Name(name)
+PrimitiveType::PrimitiveType(const String& name, const ObjectFactory& factory)
+	: m_Name(name), m_Factory(factory)
 { }
 
 String PrimitiveType::GetName(void) const
@@ -58,6 +58,6 @@ int PrimitiveType::GetFieldCount(void) const
 
 ObjectFactory PrimitiveType::GetFactory(void) const
 {
-	return NULL;
+	return m_Factory;
 }
 

lib/base/primitivetype.hpp

@@ -30,7 +30,7 @@ namespace icinga
 class I2_BASE_API PrimitiveType : public Type
 {
 public:
-	PrimitiveType(const String& name);
+	PrimitiveType(const String& name, const ObjectFactory& factory = ObjectFactory());
 
 	virtual String GetName(void) const;
 	virtual Type::Ptr GetBaseType(void) const;
@@ -44,6 +44,7 @@ protected:
 
 private:
 	String m_Name;
+	ObjectFactory m_Factory;
 };
 
 #define REGISTER_BUILTIN_TYPE(type, prototype)					\
@@ -57,11 +58,11 @@ private:
 		INITIALIZE_ONCE_WITH_PRIORITY(RegisterBuiltinType, 15);		\
 	} } }
 
-#define REGISTER_PRIMITIVE_TYPE(type, prototype)				\
+#define REGISTER_PRIMITIVE_TYPE_FACTORY(type, prototype, factory)		\
 	namespace { namespace UNIQUE_NAME(prt) { namespace prt ## type {	\
 		void RegisterPrimitiveType(void)				\
 		{								\
-			icinga::Type::Ptr t = new PrimitiveType(#type);		\
+			icinga::Type::Ptr t = new PrimitiveType(#type, factory);\
 			t->SetPrototype(prototype);				\
 			icinga::Type::Register(t);				\
 			type::TypeInstance = t;					\
@@ -70,6 +71,12 @@ private:
 	} } }									\
 	DEFINE_TYPE_INSTANCE(type)
 
+#define REGISTER_PRIMITIVE_TYPE(type, prototype)				\
+	REGISTER_PRIMITIVE_TYPE_FACTORY(type, prototype, DefaultObjectFactory<type>)
+
+#define REGISTER_PRIMITIVE_TYPE_NOINST(type, prototype)				\
+	REGISTER_PRIMITIVE_TYPE_FACTORY(type, prototype, NULL)
+
 }
 
 #endif /* PRIMITIVETYPE_H */

lib/config/expression.cpp

@@ -395,6 +395,18 @@ ExpressionResult FunctionCallExpression::DoEvaluate(ScriptFrame& frame, DebugHin
 		vfunc = vfuncres.GetValue();
 	}
 
+	if (vfunc.IsObjectType<Type>()) {
+		if (m_Args.empty())
+			return VMOps::ConstructorCall(vfunc, m_DebugInfo);
+		else if (m_Args.size() == 1) {
+			ExpressionResult argres = m_Args[0]->Evaluate(frame);
+			CHECK_RESULT(argres);
+
+			return VMOps::CopyConstructorCall(vfunc, argres.GetValue(), m_DebugInfo);
+		} else
+			BOOST_THROW_EXCEPTION(ScriptError("Too many arguments for constructor.", m_DebugInfo));
+	}
+
 	if (!vfunc.IsObjectType<Function>())
 		BOOST_THROW_EXCEPTION(ScriptError("Argument is not a callable object.", m_DebugInfo));
 

lib/config/vmops.hpp

@@ -54,6 +54,38 @@ public:
 			return ScriptGlobal::Get(name);
 	}
 
+	static inline Value CopyConstructorCall(const Type::Ptr& type, const Value& value, const DebugInfo& debugInfo = DebugInfo())
+	{
+		if (type->GetName() == "String")
+			return Convert::ToString(value);
+		else if (type->GetName() == "Number")
+			return Convert::ToDouble(value);
+		else if (type->GetName() == "Boolean")
+			return Convert::ToBool(value);
+		else if (!type->IsAssignableFrom(value.GetReflectionType()))
+			BOOST_THROW_EXCEPTION(ScriptError("Invalid cast: Tried to cast object of type '" + value.GetReflectionType()->GetName() + "' to type '" + type->GetName() + "'", debugInfo));
+		else
+			return value;
+	}
+
+	static inline Value ConstructorCall(const Type::Ptr& type, const DebugInfo& debugInfo = DebugInfo())
+	{
+		if (type->GetName() == "String")
+			return "";
+		else if (type->GetName() == "Number")
+			return 0;
+		else if (type->GetName() == "Boolean")
+			return false;
+		else {
+			Object::Ptr object = type->Instantiate();
+
+			if (!object)
+				BOOST_THROW_EXCEPTION(ScriptError("Failed to instantiate object of type '" + type->GetName() + "'", debugInfo));
+
+			return object;
+		}
+	}
+
 	static inline Value FunctionCall(ScriptFrame& frame, const Value& self, const Function::Ptr& func, const std::vector<Value>& arguments)
 	{
 		boost::shared_ptr<ScriptFrame> vframe;