cmd/protoc-gen-go: unexport implementation-specific XXX fields
We modify protoc-gen-go to stop generating exported XXX fields.
The unsafe implementation is unaffected by this change since unsafe
can access fields regardless of visibility. However, for the purego
implementation, we need to respect Go visibility rules as enforced
by the reflect package.
We work around this by generating a exporter function that given
a reference to the message and the field to export, returns a reference
to the unexported field value. This exporter function is protected by
a constant such that it is not linked into the final binary in non-purego
build environment.
Updates golang/protobuf#276
Change-Id: Idf5c1f158973fa1c61187ff41440acb21c5dac94
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/185141
Reviewed-by: Damien Neil <dneil@google.com>
diff --git a/cmd/protoc-gen-go/internal_gengo/main.go b/cmd/protoc-gen-go/internal_gengo/main.go
index 3cd0c38..22d87ca 100644
--- a/cmd/protoc-gen-go/internal_gengo/main.go
+++ b/cmd/protoc-gen-go/internal_gengo/main.go
@@ -39,6 +39,22 @@
// generateOneofWrapperMethods specifies whether to generate
// XXX_OneofWrappers methods on messages with oneofs.
generateOneofWrapperMethods = false
+
+ // generateNoUnkeyedLiteralFields specifies whether to generate
+ // the XXX_NoUnkeyedLiteral field.
+ generateNoUnkeyedLiteralFields = false
+
+ // generateExportedSizeCacheFields specifies whether to generate an exported
+ // XXX_sizecache field instead of an unexported sizeCache field.
+ generateExportedSizeCacheFields = false
+
+ // generateExportedUnknownFields specifies whether to generate an exported
+ // XXX_unrecognized field instead of an unexported unknownFields field.
+ generateExportedUnknownFields = false
+
+ // generateExportedExtensionFields specifies whether to generate an exported
+ // XXX_InternalExtensions field instead of an unexported extensionFields field.
+ generateExportedExtensionFields = false
)
const (
@@ -54,11 +70,28 @@
type fileInfo struct {
*protogen.File
- allEnums []*protogen.Enum
- allEnumsByPtr map[*protogen.Enum]int // value is index into allEnums
- allMessages []*protogen.Message
- allMessagesByPtr map[*protogen.Message]int // value is index into allMessages
- allExtensions []*protogen.Extension
+ allEnums []*protogen.Enum
+ allMessages []*protogen.Message
+ allExtensions []*protogen.Extension
+
+ allEnumsByPtr map[*protogen.Enum]int // value is index into allEnums
+ allMessagesByPtr map[*protogen.Message]int // value is index into allMessages
+ allMessageFieldsByPtr map[*protogen.Message]*structFields
+}
+
+type structFields struct {
+ count int
+ unexported map[int]string
+}
+
+func (sf *structFields) append(name string) {
+ if r, _ := utf8.DecodeRuneInString(name); !unicode.IsUpper(r) {
+ if sf.unexported == nil {
+ sf.unexported = make(map[int]string)
+ }
+ sf.unexported[sf.count] = name
+ }
+ sf.count++
}
// GenerateFile generates the contents of a .pb.go file.
@@ -90,8 +123,10 @@
}
if len(f.allMessages) > 0 {
f.allMessagesByPtr = make(map[*protogen.Message]int)
+ f.allMessageFieldsByPtr = make(map[*protogen.Message]*structFields)
for i, m := range f.allMessages {
f.allMessagesByPtr[m] = i
+ f.allMessageFieldsByPtr[m] = new(structFields)
}
}
@@ -347,15 +382,28 @@
}
g.Annotate(message.GoIdent.GoName, message.Location)
g.P("type ", message.GoIdent, " struct {")
+ sf := f.allMessageFieldsByPtr[message]
for _, field := range message.Fields {
if field.Oneof != nil {
// It would be a bit simpler to iterate over the oneofs below,
// but generating the field here keeps the contents of the Go
// struct in the same order as the contents of the source
// .proto file.
- if field == field.Oneof.Fields[0] {
- genOneofField(gen, g, f, message, field.Oneof)
+ oneof := field.Oneof
+ if field != oneof.Fields[0] {
+ continue // already generated oneof field for first entry
}
+ if g.PrintLeadingComments(oneof.Location) {
+ g.P("//")
+ }
+ g.P("// Types that are valid to be assigned to ", oneofFieldName(oneof), ":")
+ for _, field := range oneof.Fields {
+ g.PrintLeadingComments(field.Location)
+ g.P("//\t*", fieldOneofType(field))
+ }
+ g.Annotate(message.GoIdent.GoName+"."+oneofFieldName(oneof), oneof.Location)
+ g.P(oneofFieldName(oneof), " ", oneofInterfaceName(oneof), " `protobuf_oneof:\"", oneof.Desc.Name(), "\"`")
+ sf.append(oneofFieldName(oneof))
continue
}
g.PrintLeadingComments(field.Location)
@@ -378,19 +426,42 @@
g.Annotate(message.GoIdent.GoName+"."+field.GoName, field.Location)
g.P(field.GoName, " ", goType, " `", strings.Join(tags, " "), "`",
deprecationComment(field.Desc.Options().(*descriptorpb.FieldOptions).GetDeprecated()))
+ sf.append(field.GoName)
}
- g.P("XXX_NoUnkeyedLiteral struct{} `json:\"-\"`")
+ if generateNoUnkeyedLiteralFields {
+ g.P("XXX_NoUnkeyedLiteral", " struct{} `json:\"-\"`")
+ sf.append("XXX_NoUnkeyedLiteral")
+ }
+ if generateExportedSizeCacheFields {
+ g.P("XXX_sizecache", " ", protoimplPackage.Ident("SizeCache"), " `json:\"-\"`")
+ sf.append("XXX_sizecache")
+ } else {
+ g.P("sizeCache", " ", protoimplPackage.Ident("SizeCache"))
+ sf.append("sizeCache")
+ }
+ if generateExportedUnknownFields {
+ g.P("XXX_unrecognized", " ", protoimplPackage.Ident("UnknownFields"), " `json:\"-\"`")
+ sf.append("XXX_unrecognized")
+ } else {
+ g.P("unknownFields", " ", protoimplPackage.Ident("UnknownFields"))
+ sf.append("unknownFields")
+ }
if message.Desc.ExtensionRanges().Len() > 0 {
+ // TODO: Remove this tag when we drop v1 support.
var tags []string
if message.Desc.Options().(*descriptorpb.MessageOptions).GetMessageSetWireFormat() {
tags = append(tags, `protobuf_messageset:"1"`)
}
- tags = append(tags, `json:"-"`)
- g.P("XXX_InternalExtensions ", protoimplPackage.Ident("ExtensionFields"), " `", strings.Join(tags, " "), "`")
+ if generateExportedExtensionFields {
+ tags = append(tags, `json:"-"`)
+ g.P("XXX_InternalExtensions", " ", protoimplPackage.Ident("ExtensionFields"), " `", strings.Join(tags, " "), "`")
+ sf.append("XXX_InternalExtensions")
+ } else {
+ g.P("extensionFields", " ", protoimplPackage.Ident("ExtensionFields"), " `", strings.Join(tags, " "), "`")
+ sf.append("extensionFields")
+ }
}
- g.P("XXX_unrecognized ", protoimplPackage.Ident("UnknownFields"), " `json:\"-\"`")
- g.P("XXX_sizecache ", protoimplPackage.Ident("SizeCache"), " `json:\"-\"`")
g.P("}")
g.P()
@@ -744,20 +815,6 @@
"google.protobuf.Value": true,
}
-// genOneofField generates the struct field for a oneof.
-func genOneofField(gen *protogen.Plugin, g *protogen.GeneratedFile, f *fileInfo, message *protogen.Message, oneof *protogen.Oneof) {
- if g.PrintLeadingComments(oneof.Location) {
- g.P("//")
- }
- g.P("// Types that are valid to be assigned to ", oneofFieldName(oneof), ":")
- for _, field := range oneof.Fields {
- g.PrintLeadingComments(field.Location)
- g.P("//\t*", fieldOneofType(field))
- }
- g.Annotate(message.GoIdent.GoName+"."+oneofFieldName(oneof), oneof.Location)
- g.P(oneofFieldName(oneof), " ", oneofInterfaceName(oneof), " `protobuf_oneof:\"", oneof.Desc.Name(), "\"`")
-}
-
// genOneofGetter generate a Get method for a oneof.
func genOneofGetter(gen *protogen.Plugin, g *protogen.GeneratedFile, f *fileInfo, message *protogen.Message, oneof *protogen.Oneof) {
g.Annotate(message.GoIdent.GoName+".Get"+oneof.GoName, oneof.Location)