[#123] Resolve funlen linter issue

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

util/protogen/internalgengo/json.go

@@ -70,6 +70,24 @@ func emitJSONParseInteger(g *protogen.GeneratedFile, ident string, method string
 	g.P(ident, " := ", typ, "(v)")
 }
 
+func emitJSONReadEnum(g *protogen.GeneratedFile, name string, enumType string) {
+	g.P(`switch v := in.Interface().(type) {
+	case string:
+		if vv, ok := `+enumType+`_value[v]; ok {
+			`+name+` = `+enumType+`(vv)
+			break
+		}
+		vv, err := `, strconvPackage.Ident("ParseInt"), `(v, 10, 32)
+		if err != nil {
+			in.AddError(err)
+			return
+		}
+		`+name+` = `+enumType+`(vv)
+	case float64:
+		`+name+` = `+enumType+`(v)
+	}`)
+}
+
 func emitJSONFieldRead(g *protogen.GeneratedFile, f *protogen.Field, name string) {
 	g.P("{")
 	defer g.P("}")
@@ -94,21 +112,7 @@ func emitJSONFieldRead(g *protogen.GeneratedFile, f *protogen.Field, name string
 
 		enumType := fieldType(g, f).String()
 		g.P("var parsedValue " + enumType)
-		g.P(`switch v := in.Interface().(type) {
+		emitJSONReadEnum(g, "parsedValue", enumType)
-		case string:
-			if vv, ok := `+enumType+`_value[v]; ok {
-				parsedValue = `+enumType+`(vv)
-				break
-			}
-			vv, err := `, strconvPackage.Ident("ParseInt"), `(v, 10, 32)
-			if err != nil {
-				in.AddError(err)
-				return
-			}
-			parsedValue = `+enumType+`(vv)
-		case float64:
-			parsedValue = `+enumType+`(v)
-		}`)
 		template = "%s = parsedValue"
 	case protoreflect.Int32Kind, protoreflect.Sint32Kind, protoreflect.Sfixed32Kind:
 		emitJSONParseInteger(g, "pv", "ParseInt", 32, "int32")