Implement joins for status queries

fixes #10060

lib/base/object.cpp

@@ -107,6 +107,11 @@ void Object::NotifyField(int id, const Value& cookie)
 	BOOST_THROW_EXCEPTION(std::runtime_error("Invalid field ID."));
 }
 
+Object::Ptr Object::NavigateField(int id) const
+{
+	BOOST_THROW_EXCEPTION(std::runtime_error("Invalid field ID."));
+}
+
 Object::Ptr Object::Clone(void) const
 {
 	BOOST_THROW_EXCEPTION(std::runtime_error("Object cannot be cloned."));

lib/base/object.hpp

@@ -109,6 +109,7 @@ public:
 	virtual Value GetField(int id) const;
 	virtual void ValidateField(int id, const Value& value, const ValidationUtils& utils);
 	virtual void NotifyField(int id, const Value& cookie = Empty);
+	virtual Object::Ptr NavigateField(int id) const;
 
 #ifdef I2_DEBUG
 	bool OwnsLock(void) const;

lib/base/type.cpp

@@ -169,11 +169,11 @@ Field TypeType::GetFieldInfo(int id) const
 		return GetBaseType()->GetFieldInfo(id);
 
 	if (id == 0)
-		return Field(0, "String", "name", NULL, 0, 0);
+		return Field(0, "String", "name", "", NULL, 0, 0);
 	else if (id == 1)
-		return Field(1, "Object", "prototype", NULL, 0, 0);
+		return Field(1, "Object", "prototype", "", NULL, 0, 0);
 	else if (id == 2)
-		return Field(2, "Type", "base", NULL, 0, 0);
+		return Field(2, "Type", "base", "", NULL, 0, 0);
 
 	throw std::runtime_error("Invalid field ID.");
 }

lib/base/type.hpp

@@ -37,8 +37,9 @@ enum FieldAttribute
 	FAConfig = 2,
 	FAState = 4,
 	FAInternal = 64,
-	FARequired = 512
+	FARequired = 512,
-}; 
+	FANavigation = 1024
+};
 
 class Type;
 
@@ -47,12 +48,13 @@ struct Field
 	int ID;
 	const char *TypeName;
 	const char *Name;
+	const char *NavigationName;
 	const char *RefTypeName;
 	int Attributes;
 	int ArrayRank;
 
-	Field(int id, const char *type, const char *name, const char *reftype, int attributes, int arrayRank)
+	Field(int id, const char *type, const char *name, const char *navigationName, const char *reftype, int attributes, int arrayRank)
-		: ID(id), TypeName(type), Name(name), RefTypeName(reftype), Attributes(attributes), ArrayRank(arrayRank)
+		: ID(id), TypeName(type), Name(name), NavigationName(navigationName), RefTypeName(reftype), Attributes(attributes), ArrayRank(arrayRank)
 	{ }
 };
 

lib/icinga/checkable-check.cpp

@@ -42,7 +42,7 @@ boost::signals2::signal<void (const Checkable::Ptr&, NotificationType, const Che
 
 CheckCommand::Ptr Checkable::GetCheckCommand(void) const
 {
-	return CheckCommand::GetByName(GetCheckCommandRaw());
+	return dynamic_pointer_cast<CheckCommand>(NavigateCheckCommandRaw());
 }
 
 TimePeriod::Ptr Checkable::GetCheckPeriod(void) const

lib/icinga/checkable.ti

@@ -20,6 +20,8 @@
 #include "icinga/icingaapplication.hpp"
 #include "icinga/customvarobject.hpp"
 #include "base/array.hpp"
+#impl_include "icinga/checkcommand.hpp"
+#impl_include "icinga/eventcommand.hpp"
 
 library icinga;
 
@@ -42,18 +44,30 @@ enum AcknowledgementType
 
 abstract class Checkable : CustomVarObject
 {
-	[config, required] name(CheckCommand) check_command (CheckCommandRaw);
+	[config, required, navigation] name(CheckCommand) check_command (CheckCommandRaw) {
+		navigate {{{
+			return CheckCommand::GetByName(GetCheckCommandRaw());
+		}}}
+	};
 	[config] int max_check_attempts {
 		default {{{ return 3; }}}
 	};
-	[config] name(TimePeriod) check_period (CheckPeriodRaw);
+	[config, navigation] name(TimePeriod) check_period (CheckPeriodRaw) {
+		navigate {{{
+			return TimePeriod::GetByName(GetCheckPeriodRaw());
+		}}}
+	};
 	[config] double check_interval {
 		default {{{ return 5 * 60; }}}
 	};
 	[config] double retry_interval {
 		default {{{ return 60; }}}
 	};
-	[config] name(EventCommand) event_command (EventCommandRaw);
+	[config, navigation] name(EventCommand) event_command (EventCommandRaw) {
+		navigate {{{
+			return EventCommand::GetByName(GetEventCommandRaw());
+		}}}
+	};
 	[config] bool volatile;
 	[config] double flapping_threshold {
 		default {{{ return 30; }}}
@@ -137,7 +151,11 @@ abstract class Checkable : CustomVarObject
 		get {{{ return false; }}}
 	};
 
-	[config] name(Endpoint) command_endpoint (CommandEndpointRaw);
+	[config, navigation] name(Endpoint) command_endpoint (CommandEndpointRaw) {
+		navigate {{{
+			return Endpoint::GetByName(GetCommandEndpointRaw());
+		}}}
+	};
 };
 
 }

lib/icinga/dependency.ti

@@ -40,8 +40,13 @@ class Dependency : CustomVarObject < DependencyNameComposer
 	load_after Host;
 	load_after Service;
 
-	[config, required] name(Host) child_host_name;
+	[config, required, navigation(child_host)] name(Host) child_host_name {
-	[config] String child_service_name {
+		navigate {{{
+			return Host::GetByName(GetChildHostName());
+		}}}
+	};
+
+	[config, navigation(child_service)] String child_service_name {
 		track {{{
 			if (!oldValue.IsEmpty()) {
 				Service::Ptr service = Service::GetByNamePair(GetParentHostName(), oldValue);
@@ -53,10 +58,22 @@ class Dependency : CustomVarObject < DependencyNameComposer
 				DependencyGraph::RemoveDependency(this, service.get());
 			}
 		}}}
+		navigate {{{
+			if (GetChildServiceName().IsEmpty())
+				return Service::Ptr();
+
+			Host::Ptr host = Host::GetByName(GetChildHostName());
+			return host->GetServiceByShortName(GetChildServiceName());
+		}}}
 	};
 
-	[config, required] name(Host) parent_host_name;
+	[config, required, navigation(parent_host)] name(Host) parent_host_name {
-	[config] String parent_service_name {
+		navigate {{{
+			return Host::GetByName(GetParentHostName());
+		}}}
+	};
+
+	[config, navigation(parent_service)] String parent_service_name {
 		track {{{
 			if (!oldValue.IsEmpty()) {
 				Service::Ptr service = Service::GetByNamePair(GetParentHostName(), oldValue);
@@ -68,9 +85,20 @@ class Dependency : CustomVarObject < DependencyNameComposer
 				DependencyGraph::RemoveDependency(this, service.get());
 			}
 		}}}
+		navigate {{{
+			if (GetParentServiceName().IsEmpty())
+				return Service::Ptr();
+
+			Host::Ptr host = Host::GetByName(GetParentHostName());
+			return host->GetServiceByShortName(GetParentServiceName());
+		}}}
 	};
 
-	[config] name(TimePeriod) period (PeriodRaw);
+	[config, navigation] name(TimePeriod) period (PeriodRaw) {
+		navigate {{{
+			return TimePeriod::GetByName(GetPeriodRaw());
+		}}}
+	};
 
 	[config] array(double) states;
 	int state_filter_real (StateFilter);

lib/icinga/notification.ti

@@ -18,6 +18,7 @@
  ******************************************************************************/
 
 #include "icinga/customvarobject.hpp"
+#impl_include "icinga/notificationcommand.hpp"
 #impl_include "icinga/service.hpp"
 
 library icinga;
@@ -39,11 +40,19 @@ class Notification : CustomVarObject < NotificationNameComposer
 	load_after Host;
 	load_after Service;
 
-	[config, protected, required] name(NotificationCommand) command (CommandRaw);
+	[config, protected, required, navigation] name(NotificationCommand) command (CommandRaw) {
+		navigate {{{
+			return NotificationCommand::GetByName(GetCommandRaw());
+		}}}
+	};
 	[config] double interval {
 		default {{{ return 1800; }}}
 	};
-	[config] name(TimePeriod) period (PeriodRaw);
+	[config, navigation] name(TimePeriod) period (PeriodRaw) {
+		navigate {{{
+			return TimePeriod::GetByName(GetPeriodRaw());
+		}}}
+	};
 	[config, protected] array(name(User)) users (UsersRaw);
 	[config, protected] array(name(UserGroup)) user_groups (UserGroupsRaw);
 	[config] Dictionary::Ptr times;
@@ -51,8 +60,12 @@ class Notification : CustomVarObject < NotificationNameComposer
 	int type_filter_real (TypeFilter);
 	[config] array(double) states;
 	int state_filter_real (StateFilter);
-	[config, protected, required] name(Host) host_name;
+	[config, protected, required, navigation(host)] name(Host) host_name {
-	[config, protected] String service_name {
+		navigate {{{
+			return Host::GetByName(GetHostName());
+		}}}
+	};
+	[config, protected, navigation(service)] String service_name {
 		track {{{
 			if (!oldValue.IsEmpty()) {
 				Service::Ptr service = Service::GetByNamePair(GetHostName(), oldValue);
@@ -64,6 +77,13 @@ class Notification : CustomVarObject < NotificationNameComposer
 				DependencyGraph::RemoveDependency(this, service.get());
 			}
 		}}}
+		navigate {{{
+			if (GetServiceName().IsEmpty())
+				return Service::Ptr();
+
+			Host::Ptr host = Host::GetByName(GetHostName());
+			return host->GetServiceByShortName(GetServiceName());
+		}}}
 	};
 
 	[state] Array::Ptr notified_users {
@@ -75,7 +95,11 @@ class Notification : CustomVarObject < NotificationNameComposer
 	[state, set_protected] Value notification_number;
 	[state] double last_problem_notification;
 
-	[config] name(Endpoint) command_endpoint (CommandEndpointRaw);
+	[config, navigation] name(Endpoint) command_endpoint (CommandEndpointRaw) {
+		navigate {{{
+			return Endpoint::GetByName(GetCommandEndpointRaw());
+		}}}
+	};
 };
 
 validator Notification {

lib/icinga/scheduleddowntime.ti

@@ -39,8 +39,12 @@ class ScheduledDowntime : CustomVarObject < ScheduledDowntimeNameComposer
 	load_after Host;
 	load_after Service;
 
-	[config, protected, required] name(Host) host_name;
+	[config, protected, required, navigation(host)] name(Host) host_name {
-	[config, protected] String service_name {
+		navigate {{{
+			return Host::GetByName(GetHostName());
+		}}}
+	};
+	[config, protected, navigation(service)] String service_name {
 		track {{{
 			if (!oldValue.IsEmpty()) {
 				Service::Ptr service = Service::GetByNamePair(GetHostName(), oldValue);
@@ -52,6 +56,13 @@ class ScheduledDowntime : CustomVarObject < ScheduledDowntimeNameComposer
 				DependencyGraph::RemoveDependency(this, service.get());
 			}
 		}}}
+		navigate {{{
+			if (GetServiceName().IsEmpty())
+				return Service::Ptr();
+
+			Host::Ptr host = Host::GetByName(GetHostName());
+			return host->GetServiceByShortName(GetServiceName());
+		}}}
 	};
 
 	[config, required] String author;

lib/icinga/service.hpp

@@ -41,7 +41,7 @@ public:
 
 	static Service::Ptr GetByNamePair(const String& hostName, const String& serviceName);
 
-	Host::Ptr GetHost(void) const;
+	virtual Host::Ptr GetHost(void) const override;
 
 	virtual bool ResolveMacro(const String& macro, const CheckResult::Ptr& cr, Value *result) const override;
 

lib/icinga/service.ti

@@ -53,6 +53,12 @@ class Service : Checkable < ServiceNameComposer
 		}}}
 	};
 	[config, required] name(Host) host_name;
+	[no_storage, navigation] Host::Ptr host {
+		get;
+		navigate {{{
+			return GetHost();
+		}}}
+	};
 	[enum, no_storage] ServiceState "state" {
 		get {{{
 			return GetStateRaw();

lib/icinga/user.ti

@@ -38,7 +38,12 @@ class User : CustomVarObject
 	[config] array(name(UserGroup)) groups {
 		default {{{ return new Array(); }}}
 	};
-	[config] name(TimePeriod) period (PeriodRaw);
+	[config, navigation] name(TimePeriod) period (PeriodRaw) {
+		navigate {{{
+			return TimePeriod::GetByName(GetPeriodRaw());
+		}}}
+	};
+
 	[config] array(double) types;
 	int type_filter_real (TypeFilter);
 	[config] array(double) states;

lib/remote/filterutility.cpp

@@ -78,10 +78,28 @@ String ConfigObjectTargetProvider::GetPluralName(const String& type) const
 	return Type::GetByName(type)->GetPluralName();
 }
 
-static void FilteredAddTarget(ScriptFrame& frame, const String& varName, Expression *ufilter, std::vector<Value>& result, const Value& target)
+static void FilteredAddTarget(ScriptFrame& frame, Expression *ufilter, std::vector<Value>& result, const Object::Ptr& target)
 {
+	Type::Ptr type = target->GetReflectionType();
+	String varName = type->GetName();
+	boost::algorithm::to_lower(varName);
+
 	frame.Locals->Set(varName, target);
 
+	for (int fid = 0; fid < type->GetFieldCount(); fid++) {
+		Field field = type->GetFieldInfo(fid);
+
+		if ((field.Attributes & FANavigation) == 0)
+			continue;
+
+		Object::Ptr joinedObj = target->NavigateField(fid);
+
+		varName = field.TypeName;
+		boost::algorithm::to_lower(varName);
+
+		frame.Locals->Set(varName, joinedObj);
+	}
+
 	if (Convert::ToBool(ufilter->Evaluate(frame)))
 		result.push_back(target);
 }
@@ -153,11 +171,8 @@ std::vector<Value> FilterUtility::GetFilterTargets(const QueryDescription& qd, c
 			}
 		}
 
-		String varName = type;
-		boost::algorithm::to_lower(varName);
-
 		try {
-			provider->FindTargets(type, boost::bind(&FilteredAddTarget, boost::ref(frame), varName, ufilter, boost::ref(result), _1));
+			provider->FindTargets(type, boost::bind(&FilteredAddTarget, boost::ref(frame), ufilter, boost::ref(result), _1));
 		} catch (const std::exception& ex) {
 			delete ufilter;
 			throw;

lib/remote/statusqueryhandler.cpp

@@ -46,8 +46,15 @@ bool StatusQueryHandler::HandleRequest(const ApiUser::Ptr& user, HttpRequest& re
 	QueryDescription qd;
 	qd.Types.insert(type->GetName());
 
-	std::vector<String> joinTypes;
+	std::vector<String> joinAttrs;
-	joinTypes.push_back(type->GetName());
+	joinAttrs.push_back("");
+
+	for (int fid = 0; fid < type->GetFieldCount(); fid++) {
+		Field field = type->GetFieldInfo(fid);
+
+		if (field.Attributes & FANavigation)
+			joinAttrs.push_back(field.Name);
+	}
 
 	Dictionary::Ptr params = HttpUtility::FetchRequestParameters(request);
 
@@ -80,17 +87,44 @@ bool StatusQueryHandler::HandleRequest(const ApiUser::Ptr& user, HttpRequest& re
 		Dictionary::Ptr resultAttrs = new Dictionary();
 		result1->Set("attrs", resultAttrs);
 
-		BOOST_FOREACH(const String& joinType, joinTypes) {
+		BOOST_FOREACH(const String& joinAttr, joinAttrs) {
-			String prefix = joinType;
+			Object::Ptr joinedObj;
+			String prefix;
+
+			if (joinAttr.IsEmpty()) {
+				joinedObj = obj;
+				prefix = type->GetName();
+			} else {
+				int fid = type->GetFieldId(joinAttr);
+				joinedObj = static_cast<Object::Ptr>(obj)->NavigateField(fid);
+
+				if (!joinedObj)
+					continue;
+
+				Field field = type->GetFieldInfo(fid);
+				prefix = field.NavigationName;
+			}
+
 			boost::algorithm::to_lower(prefix);
 
-			for (int fid = 0; fid < type->GetFieldCount(); fid++) {
+			Type::Ptr joinedType = joinedObj->GetReflectionType();
-				Field field = type->GetFieldInfo(fid);
+
+			for (int fid = 0; fid < joinedType->GetFieldCount(); fid++) {
+				Field field = joinedType->GetFieldInfo(fid);
 				String aname = prefix + "." + field.Name;
 				if (!attrs.empty() && attrs.find(aname) == attrs.end())
 					continue;
 
-				Value val = static_cast<Object::Ptr>(obj)->GetField(fid);
+				Value val = joinedObj->GetField(fid);
+
+				/* hide internal navigation fields */
+				if (field.Attributes & FANavigation) {
+					Value nval = joinedObj->NavigateField(fid);
+
+					if (val == nval)
+						continue;
+				}
+
 				Value sval = Serialize(val, FAConfig | FAState);
 				resultAttrs->Set(aname, sval);
 			}

lib/remote/typequeryhandler.cpp

@@ -138,6 +138,8 @@ bool TypeQueryHandler::HandleRequest(const ApiUser::Ptr& user, HttpRequest& requ
 			fieldInfo->Set("type", field.TypeName);
 			if (field.RefTypeName)
 				fieldInfo->Set("ref_type", field.RefTypeName);
+			if (field.Attributes & FANavigation)
+				fieldInfo->Set("navigation_name", field.NavigationName);
 			fieldInfo->Set("array_rank", field.ArrayRank);
 
 			Dictionary::Ptr attributeInfo = new Dictionary();
@@ -147,7 +149,7 @@ bool TypeQueryHandler::HandleRequest(const ApiUser::Ptr& user, HttpRequest& requ
 			attributeInfo->Set("state", static_cast<bool>(field.Attributes & FAState));
 			attributeInfo->Set("internal", static_cast<bool>(field.Attributes & FAInternal));
 			attributeInfo->Set("required", static_cast<bool>(field.Attributes & FARequired));
-
+			attributeInfo->Set("navigation", static_cast<bool>(field.Attributes & FANavigation));
 		}
 	}
 

lib/remote/zone.ti

@@ -26,7 +26,12 @@ namespace icinga
 
 class Zone : ConfigObject
 {
-	[config] name(Zone) parent (ParentRaw);
+	[config, navigation] name(Zone) parent (ParentRaw) {
+		navigate {{{
+			return Zone::GetByName(GetParentRaw());
+		}}}
+	};
+
 	[config] array(name(Endpoint)) endpoints (EndpointsRaw);
 	[config] bool global;
 };

tools/mkclass/class_lexer.ll

@@ -145,6 +145,7 @@ set_protected			{ yylval->num = FASetProtected; return T_FIELD_ATTRIBUTE; }
 protected			{ yylval->num = FAGetProtected | FASetProtected; return T_FIELD_ATTRIBUTE; }
 internal			{ yylval->num = FAInternal; return T_FIELD_ATTRIBUTE; }
 no_storage			{ yylval->num = FANoStorage; return T_FIELD_ATTRIBUTE; }
+navigation			{ return T_NAVIGATION; }
 validator			{ return T_VALIDATOR; }
 required			{ return T_REQUIRED; }
 name				{ return T_NAME; }
@@ -153,8 +154,9 @@ default				{ yylval->num = FTDefault; return T_FIELD_ACCESSOR_TYPE; }
 get				{ yylval->num = FTGet; return T_FIELD_ACCESSOR_TYPE; }
 set				{ yylval->num = FTSet; return T_FIELD_ACCESSOR_TYPE; }
 track				{ yylval->num = FTTrack; return T_FIELD_ACCESSOR_TYPE; }
+navigate			{ yylval->num = FTNavigate; return T_FIELD_ACCESSOR_TYPE; }
 \"[^\"]+\"			{ yylval->text = strdup(yytext + 1); yylval->text[strlen(yylval->text) - 1] = '\0'; return T_STRING; }
-\<[^>]+\>			{ yylval->text = strdup(yytext + 1); yylval->text[strlen(yylval->text) - 1] = '\0'; return T_ANGLE_STRING; }
+\<[^ \>]*\>			{ yylval->text = strdup(yytext + 1); yylval->text[strlen(yylval->text) - 1] = '\0'; return T_ANGLE_STRING; }
 [a-zA-Z_][:a-zA-Z0-9\-_]*	{ yylval->text = strdup(yytext); return T_IDENTIFIER; }
 
 .				return yytext[0];

tools/mkclass/class_parser.yy

@@ -65,6 +65,7 @@ using namespace icinga;
 %token T_NAMESPACE "namespace (T_NAMESPACE)"
 %token T_VALIDATOR "validator (T_VALIDATOR)"
 %token T_REQUIRED "required (T_REQUIRED)"
+%token T_NAVIGATION "navigation (T_NAVIGATION)"
 %token T_NAME "name (T_NAME)"
 %token T_ARRAY "array (T_ARRAY)"
 %token T_STRING "string (T_STRING)"
@@ -89,9 +90,9 @@ using namespace icinga;
 %type <text> angle_impl_include
 %type <text> code
 %type <num> T_FIELD_ATTRIBUTE
-%type <num> field_attribute
+%type <field> field_attribute
-%type <num> field_attributes
+%type <field> field_attributes
-%type <num> field_attribute_list
+%type <field> field_attribute_list
 %type <num> T_FIELD_ACCESSOR_TYPE
 %type <num> T_CLASS_ATTRIBUTE
 %type <num> class_attribute_list
@@ -328,9 +329,7 @@ field_type: identifier
 
 class_field: field_attribute_list field_type identifier alternative_name_specifier field_accessor_list ';'
 	{
-		Field *field = new Field();
+		Field *field = $1;
-
-		field->Attributes = $1;
 
 		if ((field->Attributes & (FAConfig | FAState)) == 0)
 			field->Attributes |= FAEphemeral;
@@ -363,6 +362,10 @@ class_field: field_attribute_list field_type identifier alternative_name_specifi
 				case FTTrack:
 					field->TrackAccessor = it->Accessor;
 					break;
+				case FTNavigate:
+					field->NavigateAccessor = it->Accessor;
+					field->PureNavigateAccessor = it->Pure;
+					break;
 			}
 		}
 
@@ -392,7 +395,7 @@ alternative_name_specifier: /* empty */
 
 field_attribute_list: /* empty */
 	{
-		$$ = 0;
+		$$ = new Field();
 	}
 	| '[' field_attributes ']'
 	{
@@ -402,21 +405,39 @@ field_attribute_list: /* empty */
 
 field_attribute: T_FIELD_ATTRIBUTE
 	{
-		$$ = $1;
+		$$ = new Field();
+		$$->Attributes = $1;
 	}
 	| T_REQUIRED
 	{
-		$$ = FARequired;
+		$$ = new Field();
+		$$->Attributes = FARequired;
+	}
+	| T_NAVIGATION '(' identifier ')'
+	{
+		$$ = new Field();
+		$$->Attributes = FANavigation;
+		$$->NavigationName = $3;
+		std::free($3);
+	}
+	| T_NAVIGATION
+	{
+		$$ = new Field();
+		$$->Attributes = FANavigation;
 	}
 	;
 
 field_attributes: /* empty */
 	{
-		$$ = 0;
+		$$ = new Field();
 	}
 	| field_attributes ',' field_attribute
 	{
-		$$ = $1 | $3;
+		$$ = $1;
+		$$->Attributes |= $3->Attributes;
+		if (!$3->NavigationName.empty())
+			$$->NavigationName = $3->NavigationName;
+		delete $3;
 	}
 	| field_attribute
 	{

tools/mkclass/classcompiler.cpp

@@ -366,7 +366,7 @@ void ClassCompiler::HandleClass(const Klass& klass, const ClassDebugInfo&)
 				nameref = "NULL";
 
 			m_Impl << "\t\t" << "case " << num << ":" << std::endl
-				 << "\t\t\t" << "return Field(" << num << ", \"" << ftype << "\", \"" << it->Name << "\", " << nameref << ", " << it->Attributes << ", " << it->Type.ArrayRank << ");" << std::endl;
+				 << "\t\t\t" << "return Field(" << num << ", \"" << ftype << "\", \"" << it->Name << "\", \"" << (it->NavigationName.empty() ? it->Name : it->NavigationName) << "\", "  << nameref << ", " << it->Attributes << ", " << it->Type.ArrayRank << ");" << std::endl;
 			num++;
 		}
 
@@ -695,6 +695,42 @@ void ClassCompiler::HandleClass(const Klass& klass, const ClassDebugInfo&)
 
 		m_Impl << "}" << std::endl << std::endl;
 
+		/* NavigateField */
+		m_Header << "protected:" << std::endl
+			 << "\t" << "virtual Object::Ptr NavigateField(int id) const override;" << std::endl;
+
+		m_Impl << "Object::Ptr ObjectImpl<" << klass.Name << ">::NavigateField(int id) const" << std::endl
+		       << "{" << std::endl;
+
+		if (!klass.Parent.empty())
+			m_Impl << "\t" << "int real_id = id - " << klass.Parent << "::TypeInstance->GetFieldCount(); " << std::endl
+			       << "\t" << "if (real_id < 0) { return " << klass.Parent << "::NavigateField(id); }" << std::endl;
+
+		m_Impl << "\t" << "switch (";
+
+		if (!klass.Parent.empty())
+			m_Impl << "real_id";
+		else
+			m_Impl << "id";
+
+		m_Impl << ") {" << std::endl;
+
+		num = 0;
+		for (it = klass.Fields.begin(); it != klass.Fields.end(); it++) {
+			if (it->Attributes & FANavigation) {
+				m_Impl << "\t\t" << "case " << num << ":" << std::endl
+				       << "\t\t\t" << "return Navigate" << it->GetFriendlyName() << "();" << std::endl;
+			}
+
+			num++;
+		}
+
+		m_Impl << "\t\t" << "default:" << std::endl
+		       << "\t\t\t" << "throw std::runtime_error(\"Invalid field ID.\");" << std::endl
+		       << "\t" << "}" << std::endl;
+
+		m_Impl << "}" << std::endl << std::endl;
+
 		/* getters */
 		for (it = klass.Fields.begin(); it != klass.Fields.end(); it++) {
 			std::string prot;
@@ -811,6 +847,31 @@ void ClassCompiler::HandleClass(const Klass& klass, const ClassDebugInfo&)
 			m_Impl << "}" << std::endl << std::endl;
 		}
 
+		/* navigation */
+		for (it = klass.Fields.begin(); it != klass.Fields.end(); it++) {
+			if ((it->Attributes & FANavigation) == 0)
+				continue;
+
+			m_Header << "public:" << std::endl
+				 << "\t" << "virtual Object::Ptr Navigate" << it->GetFriendlyName() << "(void) const";
+
+			if (it->PureNavigateAccessor) {
+				m_Header << " = 0;" << std::endl;
+			} else {
+				m_Header << ";" << std::endl;
+
+				m_Impl << "Object::Ptr ObjectImpl<" << klass.Name << ">::Navigate" << it->GetFriendlyName() << "(void) const" << std::endl
+				       << "{" << std::endl;
+
+				if (it->NavigateAccessor.empty())
+					m_Impl << "\t" << "return Get" << it->GetFriendlyName() << "();" << std::endl;
+				else
+					m_Impl << "\t" << it->NavigateAccessor << std::endl;
+
+				m_Impl << "}" << std::endl << std::endl;
+			}
+		}
+
 		/* start/stop */
 		if (needs_tracking) {
 			m_Header << "virtual void Start(void) override;" << std::endl

tools/mkclass/classcompiler.hpp

@@ -43,7 +43,8 @@ enum FieldAccessorType
 	FTGet,
 	FTSet,
 	FTDefault,
-	FTTrack
+	FTTrack,
+	FTNavigate
 };
 
 struct FieldAccessor
@@ -69,7 +70,8 @@ enum FieldAttribute
 	FAInternal = 64,
 	FANoStorage = 128,
 	FALoadDependency = 256,
-	FARequired = 512
+	FARequired = 512,
+	FANavigation = 1024
 };
 
 struct FieldType
@@ -116,9 +118,12 @@ struct Field
 	bool PureSetAccessor;
 	std::string DefaultAccessor;
 	std::string TrackAccessor;
+	std::string NavigationName;
+	std::string NavigateAccessor;
+	bool PureNavigateAccessor;
 
 	Field(void)
-		: Attributes(0), PureGetAccessor(false), PureSetAccessor(false)
+		: Attributes(0), PureGetAccessor(false), PureSetAccessor(false), PureNavigateAccessor(false)
 	{ }
 
 	inline std::string GetFriendlyName(void) const