//Collapses a proto fieldpath into a go fieldpath. They are different if some of the fields in the fieldpath have been embedded.
func Collapse(rootPkg string, rootMsg string, path string, descriptorSet *descriptor.FileDescriptorSet) (string, error) {
msg := descriptorSet.GetMessage(rootPkg, rootMsg)
if msg == nil {
return "", &errUndefined{rootPkg, rootMsg, path}
}
paths := strings.Split(path, ".")
if len(paths) == 0 {
return "", &errUndefined{rootPkg, rootMsg, path}
}
if len(paths) == 1 {
return path, nil
}
for _, f := range msg.GetField() {
if f.GetName() != paths[0] {
continue
}
if f.IsMessage() {
newRootPkg, newRootMsg := descriptorSet.FindMessage(rootPkg, rootMsg, f.GetName())
if len(newRootPkg) == 0 || len(newRootMsg) == 0 {
return "", &errUndefined{rootPkg, rootMsg, path}
}
newPath, err := Collapse(newRootPkg, newRootMsg, strings.Join(paths[1:], "."), descriptorSet)
if err != nil {
return "", err
}
if gogoproto.IsEmbed(f) {
return newPath, nil
} else {
return paths[0] + "." + newPath, nil
}
}
}
if msg.IsExtendable() {
newRootPkg, f := descriptorSet.FindExtension(rootPkg, rootMsg, paths[0])
if f == nil {
return "", &errUndefined{rootPkg, rootMsg, path}
}
typeName := f.GetTypeName()
typeNames := strings.Split(typeName, ".")
newRootMsg := typeName
if len(typeNames) > 1 {
newRootMsg = typeNames[len(typeNames)-1]
}
newPath, err := Collapse(newRootPkg, newRootMsg, strings.Join(paths[1:], "."), descriptorSet)
if err != nil {
return "", err
}
if gogoproto.IsEmbed(f) {
return newPath, nil
} else {
return paths[0] + "." + newPath, nil
}
}
return "", nil
}
// The NoMerge function checks that the marshaled protocol buffer does not require any merging when unmarshaling
// When this property holds, streaming processing is possible.
//
// See below quotes from the protocol buffer documentation that describes how merging should work.
//
// https://developers.google.com/protocol-buffers/docs/encoding#optional
//
// Normally, an encoded message would never have more than one instance of an optional or required field.
// However, parsers are expected to handle the case in which they do.
// For numeric types and strings, if the same value appears multiple times, the parser accepts the last value it sees.
// For embedded message fields, the parser merges multiple instances of the same field,
// as if with the Message::MergeFrom method – that is,
// all singular scalar fields in the latter instance replace those in the former,
// singular embedded messages are merged, and repeated fields are concatenated.
// The effect of these rules is that parsing the concatenation of two encoded messages produces
// exactly the same result as if you had parsed the two messages separately and merged the resulting objects.
// That is, this:
//
// MyMessage message;
// message.ParseFromString(str1 + str2);
//
// is equivalent to this:
//
// MyMessage message, message2;
// message.ParseFromString(str1);
// message2.ParseFromString(str2);
// message.MergeFrom(message2);
//
// This property is occasionally useful, as it allows you to merge two messages even if you do not know their types.
//
// https://developers.google.com/protocol-buffers/docs/encoding#order
//
// However, protocol buffer parsers must be able to parse fields in any order,
// as not all messages are created by simply serializing an object – for instance,
// it's sometimes useful to merge two messages by simply concatenating them.
func NoMerge(buf []byte, descriptorSet *descriptor.FileDescriptorSet, rootPkg string, rootMsg string) error {
msg := descriptorSet.GetMessage(rootPkg, rootMsg)
if msg == nil {
return &errUndefined{rootPkg, rootMsg, ""}
}
i := 0
seen := make(map[int32]bool)
for i < len(buf) {
key, n, err := decodeVarint(buf, i)
if err != nil {
return err
}
i = i + n
fieldNum := int32(key >> 3)
wireType := int(key & 0x7)
field := getFieldNumber(descriptorSet, rootPkg, rootMsg, msg, fieldNum)
if field == nil || field.GetLabel() == descriptor.FieldDescriptorProto_LABEL_REPEATED {
i, err = skip(buf, i, wireType)
if err != nil {
return err
}
continue
}
if seen[fieldNum] {
return &errMerge{msg.GetName() + "." + field.GetName()}
}
seen[fieldNum] = true
if !field.IsMessage() {
i, err = skip(buf, i, wireType)
if err != nil {
return err
}
continue
}
length, n, err := decodeVarint(buf, i)
if err != nil {
return err
}
i += n
fieldPkg, fieldMsg := descriptorSet.FindMessage(rootPkg, rootMsg, field.GetName())
if len(fieldMsg) == 0 {
return &errUndefined{rootPkg, rootMsg, field.GetName()}
}
err = NoMerge(buf[i:i+int(length)], descriptorSet, fieldPkg, fieldMsg)
if err != nil {
return err
}
i += int(length)
}
return nil
}
func toMessages(elems []string, fileDescriptorSet *descriptor.FileDescriptorSet, messages []string) ([]string, error) {
if len(elems) < 2 {
return nil, &errUndefinedMsg{elems[0], "???"}
}
msg := fileDescriptorSet.GetMessage(elems[0], elems[1])
if msg == nil {
return nil, &errUndefinedMsg{elems[0], elems[1]}
}
if len(elems) == 2 {
messages = append(messages, elems[0]+"."+elems[1])
return messages, nil
}
newPkg, newMsg := fileDescriptorSet.FindMessage(elems[0], elems[1], elems[2])
if len(newMsg) == 0 {
return nil, &errUndefined{elems[0], elems[1], elems[2]}
}
messages = append(messages, elems[0]+"."+elems[1])
elems[1] = newPkg
elems[2] = newMsg
return toMessages(elems[1:], fileDescriptorSet, messages)
}
//Converts a marshalled protocol buffer to string.
//It does this pretty effienctly by not combining slices.
//It rather prints every element of the slice seperately.
//This is typically used for debugging.
func ToString(rootPkg string, rootMsg string, desc *descriptor.FileDescriptorSet, fpath string, buf []byte, tabs int, writer io.Writer) error {
w := &stringWriter{tabs, writer}
messagePkg := rootPkg
messageName := rootMsg
if len(fpath) > 0 {
fd, err := new(rootPkg, rootMsg, desc, fpath)
if err != nil {
panic(err)
}
messagePkg = fd.rootPkg
messageName = fd.rootMsg
}
msg := desc.GetMessage(messagePkg, messageName)
if msg == nil {
panic("message not found: " + messagePkg + "." + messageName)
}
offset := 0
for offset < len(buf) {
key, n, err := decodeVarint(buf, offset)
if err != nil {
panic(err)
}
offset += n
fieldNum := int32(key >> 3)
found := false
for _, f := range msg.GetField() {
if f.IsPacked() {
panic("not implemented")
}
if f.GetNumber() != fieldNum {
continue
}
found = true
if f.GetType() == descriptor.FieldDescriptorProto_TYPE_MESSAGE {
length, nn, err := decodeVarint(buf, offset)
if err != nil {
panic(err)
}
offset += nn
w.tab()
w.String(f.GetName() + `:{` + "\n")
err = ToString(messagePkg, messageName, desc, f.GetName(), buf[offset:offset+int(length)], tabs+1, writer)
if err != nil {
return err
}
offset += int(length)
w.tab()
w.String(`}` + "\n")
break
} else {
w.tab()
w.String(f.GetName() + `:`)
var n int
var err error
switch f.GetType() {
case descriptor.FieldDescriptorProto_TYPE_DOUBLE:
n, err = DecFloat64(buf, offset, w)
case descriptor.FieldDescriptorProto_TYPE_FLOAT:
n, err = DecFloat32(buf, offset, w)
case descriptor.FieldDescriptorProto_TYPE_INT64:
n, err = DecInt64(buf, offset, w)
case descriptor.FieldDescriptorProto_TYPE_UINT64:
n, err = DecUint64(buf, offset, w)
case descriptor.FieldDescriptorProto_TYPE_INT32:
n, err = DecInt32(buf, offset, w)
case descriptor.FieldDescriptorProto_TYPE_FIXED64:
n, err = DecFixed64(buf, offset, w)
case descriptor.FieldDescriptorProto_TYPE_FIXED32:
n, err = DecFixed32(buf, offset, w)
case descriptor.FieldDescriptorProto_TYPE_BOOL:
n, err = DecBool(buf, offset, w)
case descriptor.FieldDescriptorProto_TYPE_STRING:
n, err = DecString(buf, offset, w)
case descriptor.FieldDescriptorProto_TYPE_GROUP:
panic("not implemented")
case descriptor.FieldDescriptorProto_TYPE_BYTES:
n, err = DecBytes(buf, offset, w)
case descriptor.FieldDescriptorProto_TYPE_UINT32:
n, err = DecUint32(buf, offset, w)
case descriptor.FieldDescriptorProto_TYPE_ENUM:
n, err = DecInt32(buf, offset, w)
case descriptor.FieldDescriptorProto_TYPE_SFIXED32:
n, err = DecSfixed32(buf, offset, w)
case descriptor.FieldDescriptorProto_TYPE_SFIXED64:
n, err = DecSfixed64(buf, offset, w)
case descriptor.FieldDescriptorProto_TYPE_SINT32:
n, err = DecSint32(buf, offset, w)
case descriptor.FieldDescriptorProto_TYPE_SINT64:
n, err = DecSint64(buf, offset, w)
default:
panic("unreachable")
}
offset += n
if err != nil {
panic(err)
}
w.String(",\n")
break
}
}
if !found {
for _, extRange := range msg.GetExtensionRange() {
if extRange.GetStart() <= fieldNum && fieldNum <= extRange.GetEnd() {
found = true
break
}
}
w.tab()
offset -= n
nn, err := proto.Skip(buf[offset:])
if err != nil {
panic(err)
}
if !found {
w.String("XXX_unrecognized:")
} else {
w.String("XXX_extensions:")
extPkg, ext := desc.FindExtensionByFieldNumber(messagePkg, messageName, fieldNum)
if ext != nil && ext.IsMessage() {
names := strings.Split(ext.GetTypeName(), ".")
if len(names) == 3 {
_, nnn, err := decodeVarint(buf, offset+n)
if err != nil {
panic(err)
}
w.tab()
w.String(extPkg + "." + names[2] + `:{` + "\n")
err = ToString(extPkg, names[2], desc, "", buf[offset+n+nnn:offset+nn], tabs+1, writer)
if err != nil {
return err
}
offset += nn
w.tab()
w.String(`}` + "\n")
break
} else {
panic(ext.GetTypeName())
}
}
}
w.Bytes(buf[offset : offset+nn])
w.String("\n")
offset += nn
}
}
return nil
}