Feature/212 provide overview of modified variables (#94)

* #212 Initial commit for server branch

* #212 Add manipulated variables to JsonResponse

* #212 Fixed server duplication issue when appending to array

* #212 Actually commit latest code for hungry reviewers

* #212 C API change

* Following up my own review comments

cse/cse.go

@@ -364,6 +364,41 @@ func addVariableMetadata(execution *C.cse_execution, fmu *structs.FMU) error {
 	return nil
 }
 
+func fetchManipulatedVariables(execution *C.cse_execution) []structs.ManipulatedVariable {
+	nVars := int(C.cse_get_num_modified_variables(execution))
+	if nVars <= 0 {
+		return nil
+	}
+
+	var variables = make([]C.cse_variable_id, nVars)
+	numVars := int(C.cse_get_modified_variables(execution, &variables[0], C.size_t(nVars)))
+
+	if numVars < 0 {
+		log.Println("Error while fetching modified variables: ", lastErrorMessage())
+		return nil
+	}
+
+	var varStructs = make([]structs.ManipulatedVariable, numVars)
+	for n, variable := range variables[0:numVars] {
+		slaveIndex := int(variable.slave_index)
+		valueReference := int(variable.variable_index)
+		variableType, err := parseType(variable._type)
+
+		if err != nil {
+			log.Println("Problem parsing variable type: ", variable._type)
+			return nil
+		}
+
+		varStructs[n] = structs.ManipulatedVariable{
+			slaveIndex,
+			variableType,
+			valueReference,
+		}
+	}
+
+	return varStructs
+}
+
 func simulationTeardown(sim *Simulation) (bool, string) {
 	executionDestroy(sim.Execution)
 	observerDestroy(sim.Observer)
@@ -658,6 +693,7 @@ func GenerateJsonResponse(status *structs.SimulationStatus, sim *Simulation, fee
 		response.Module = findModuleData(status, sim.MetaData, sim.Observer)
 		response.ConfigDir = status.ConfigDir
 		response.Trends = status.Trends
+		response.ManipulatedVariables = fetchManipulatedVariables(sim.Execution)
 		if sim.ScenarioManager != nil && isScenarioRunning(sim.ScenarioManager) {
 			response.RunningScenario = status.CurrentScenario
 		}

structs/structs.go

@@ -12,21 +12,28 @@ type Module struct {
 	Name    string   `json:"name,omitempty"`
 }
 
+type ManipulatedVariable struct {
+	SlaveIndex     int    `json:"slaveIndex"`
+	Type           string `json:"type"`
+	ValueReference int    `json:"valueReference"`
+}
+
 type JsonResponse struct {
-	Loaded               bool             `json:"loaded"`
-	SimulationTime       float64          `json:"time"`
-	RealTimeFactor       float64          `json:"realTimeFactor"`
-	RealTimeFactorTarget float64          `json:"realTimeFactorTarget"`
-	IsRealTimeSimulation bool             `json:"isRealTime"`
-	ConfigDir            string           `json:"configDir,omitempty"`
-	Status               string           `json:"status,omitempty"`
-	Module               Module           `json:"module,omitempty"`
-	Trends               []Trend          `json:"trends"`
-	ModuleData           *MetaData        `json:"module-data,omitempty"`
-	Feedback             *CommandFeedback `json:"feedback,omitempy"`
-	Scenarios            *[]string        `json:"scenarios,omitempty"`
-	Scenario             *interface{}     `json:"scenario,omitempty"`
-	RunningScenario      string           `json:"running-scenario"`
+	Loaded               bool                  `json:"loaded"`
+	SimulationTime       float64               `json:"time"`
+	RealTimeFactor       float64               `json:"realTimeFactor"`
+	RealTimeFactorTarget float64               `json:"realTimeFactorTarget"`
+	IsRealTimeSimulation bool                  `json:"isRealTime"`
+	ConfigDir            string                `json:"configDir,omitempty"`
+	Status               string                `json:"status,omitempty"`
+	Module               Module                `json:"module,omitempty"`
+	Trends               []Trend               `json:"trends"`
+	ModuleData           *MetaData             `json:"module-data,omitempty"`
+	Feedback             *CommandFeedback      `json:"feedback,omitempy"`
+	Scenarios            *[]string             `json:"scenarios,omitempty"`
+	Scenario             *interface{}          `json:"scenario,omitempty"`
+	RunningScenario      string                `json:"running-scenario"`
+	ManipulatedVariables []ManipulatedVariable `json:"manipulatedVariables"`
 }
 
 type TrendSignal struct {