implement mvc HandleError as requested at #1244

Former-commit-id: 58a69f9cffe67c3aa1bab5d9425c5df65e2367ed

mvc/reflect.go

@@ -1,13 +1,42 @@
 package mvc
 
-import "reflect"
+import (
+	"reflect"
 
-var baseControllerTyp = reflect.TypeOf((*BaseController)(nil)).Elem()
+	"github.com/kataras/iris/hero"
+)
+
+var (
+	baseControllerTyp = reflect.TypeOf((*BaseController)(nil)).Elem()
+	errorHandlerTyp   = reflect.TypeOf((*hero.ErrorHandler)(nil)).Elem()
+	errorTyp          = reflect.TypeOf((*error)(nil)).Elem()
+)
 
 func isBaseController(ctrlTyp reflect.Type) bool {
 	return ctrlTyp.Implements(baseControllerTyp)
 }
 
+func isErrorHandler(ctrlTyp reflect.Type) bool {
+	return ctrlTyp.Implements(errorHandlerTyp)
+}
+
+func hasErrorOutArgs(fn reflect.Method) bool {
+	n := fn.Type.NumOut()
+	if n == 0 {
+		return false
+	}
+
+	for i := 0; i < n; i++ {
+		if out := fn.Type.Out(i); out.Kind() == reflect.Interface {
+			if out.Implements(errorTyp) {
+				return true
+			}
+		}
+	}
+
+	return false
+}
+
 func getInputArgsFromFunc(funcTyp reflect.Type) []reflect.Type {
 	n := funcTyp.NumIn()
 	funcIn := make([]reflect.Type, n, n)