reflect/protoreflect: add MessageFieldTypes
The MessageFieldTypes interface (if implemented by a MessageType)
provides Go type information about the fields if they are
an enum or message type.
Change-Id: I68b20f5726377f6b0f2c20a8b6e45f9802b43f67
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/236777
Reviewed-by: Damien Neil <dneil@google.com>
diff --git a/internal/impl/message.go b/internal/impl/message.go
index c026a98..c8c3859 100644
--- a/internal/impl/message.go
+++ b/internal/impl/message.go
@@ -15,6 +15,7 @@
"google.golang.org/protobuf/internal/genid"
"google.golang.org/protobuf/reflect/protoreflect"
pref "google.golang.org/protobuf/reflect/protoreflect"
+ preg "google.golang.org/protobuf/reflect/protoregistry"
)
// MessageInfo provides protobuf related functionality for a given Go type
@@ -212,4 +213,53 @@
func (mi *MessageInfo) Zero() protoreflect.Message {
return mi.MessageOf(reflect.Zero(mi.GoReflectType).Interface())
}
-func (mi *MessageInfo) Descriptor() protoreflect.MessageDescriptor { return mi.Desc }
+func (mi *MessageInfo) Descriptor() protoreflect.MessageDescriptor {
+ return mi.Desc
+}
+func (mi *MessageInfo) Enum(i int) protoreflect.EnumType {
+ mi.init()
+ fd := mi.Desc.Fields().Get(i)
+ return Export{}.EnumTypeOf(mi.fieldTypes[fd.Number()])
+}
+func (mi *MessageInfo) Message(i int) protoreflect.MessageType {
+ mi.init()
+ fd := mi.Desc.Fields().Get(i)
+ switch {
+ case fd.IsWeak():
+ mt, _ := preg.GlobalTypes.FindMessageByName(fd.Message().FullName())
+ return mt
+ case fd.IsMap():
+ return mapEntryType{fd.Message(), mi.fieldTypes[fd.Number()]}
+ default:
+ return Export{}.MessageTypeOf(mi.fieldTypes[fd.Number()])
+ }
+}
+
+type mapEntryType struct {
+ desc protoreflect.MessageDescriptor
+ valType interface{} // zero value of enum or message type
+}
+
+func (mt mapEntryType) New() protoreflect.Message {
+ return nil
+}
+func (mt mapEntryType) Zero() protoreflect.Message {
+ return nil
+}
+func (mt mapEntryType) Descriptor() protoreflect.MessageDescriptor {
+ return mt.desc
+}
+func (mt mapEntryType) Enum(i int) protoreflect.EnumType {
+ fd := mt.desc.Fields().Get(i)
+ if fd.Enum() == nil {
+ return nil
+ }
+ return Export{}.EnumTypeOf(mt.valType)
+}
+func (mt mapEntryType) Message(i int) protoreflect.MessageType {
+ fd := mt.desc.Fields().Get(i)
+ if fd.Message() == nil {
+ return nil
+ }
+ return Export{}.MessageTypeOf(mt.valType)
+}