Prometheus endpoint (#5256)

* Add prometheus collector and route

* dep ensure -add github.com/prometheus/client_golang/prometheus

* dep ensure -update github.com/golang/protobuf

* add metrics to reserved usernames

* add comment head in metrics package

* fix style imports

* add metrics settings

* add bearer token check

* mapping metrics configs

* fix lint

* update config cheat sheet

* update conf sample, typo fix

vendor/github.com/golang/protobuf/proto/decode.go

@@ -39,8 +39,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"os"
-	"reflect"
 )
 
 // errOverflow is returned when an integer is too large to be represented.
@@ -50,10 +48,6 @@ var errOverflow = errors.New("proto: integer overflow")
 // wire type is encountered. It does not get returned to user code.
 var ErrInternalBadWireType = errors.New("proto: internal error: bad wiretype for oneof")
 
-// The fundamental decoders that interpret bytes on the wire.
-// Those that take integer types all return uint64 and are
-// therefore of type valueDecoder.
-
 // DecodeVarint reads a varint-encoded integer from the slice.
 // It returns the integer and the number of bytes consumed, or
 // zero if there is not enough.
@@ -61,7 +55,6 @@ var ErrInternalBadWireType = errors.New("proto: internal error: bad wiretype for
 // int32, int64, uint32, uint64, bool, and enum
 // protocol buffer types.
 func DecodeVarint(buf []byte) (x uint64, n int) {
-	// x, n already 0
 	for shift := uint(0); shift < 64; shift += 7 {
 		if n >= len(buf) {
 			return 0, 0
@@ -78,13 +71,7 @@ func DecodeVarint(buf []byte) (x uint64, n int) {
 	return 0, 0
 }
 
-// DecodeVarint reads a varint-encoded integer from the Buffer.
-// This is the format for the
-// int32, int64, uint32, uint64, bool, and enum
-// protocol buffer types.
-func (p *Buffer) DecodeVarint() (x uint64, err error) {
-	// x, err already 0
-
+func (p *Buffer) decodeVarintSlow() (x uint64, err error) {
 	i := p.index
 	l := len(p.buf)
 
@@ -107,6 +94,107 @@ func (p *Buffer) DecodeVarint() (x uint64, err error) {
 	return
 }
 
+// DecodeVarint reads a varint-encoded integer from the Buffer.
+// This is the format for the
+// int32, int64, uint32, uint64, bool, and enum
+// protocol buffer types.
+func (p *Buffer) DecodeVarint() (x uint64, err error) {
+	i := p.index
+	buf := p.buf
+
+	if i >= len(buf) {
+		return 0, io.ErrUnexpectedEOF
+	} else if buf[i] < 0x80 {
+		p.index++
+		return uint64(buf[i]), nil
+	} else if len(buf)-i < 10 {
+		return p.decodeVarintSlow()
+	}
+
+	var b uint64
+	// we already checked the first byte
+	x = uint64(buf[i]) - 0x80
+	i++
+
+	b = uint64(buf[i])
+	i++
+	x += b << 7
+	if b&0x80 == 0 {
+		goto done
+	}
+	x -= 0x80 << 7
+
+	b = uint64(buf[i])
+	i++
+	x += b << 14
+	if b&0x80 == 0 {
+		goto done
+	}
+	x -= 0x80 << 14
+
+	b = uint64(buf[i])
+	i++
+	x += b << 21
+	if b&0x80 == 0 {
+		goto done
+	}
+	x -= 0x80 << 21
+
+	b = uint64(buf[i])
+	i++
+	x += b << 28
+	if b&0x80 == 0 {
+		goto done
+	}
+	x -= 0x80 << 28
+
+	b = uint64(buf[i])
+	i++
+	x += b << 35
+	if b&0x80 == 0 {
+		goto done
+	}
+	x -= 0x80 << 35
+
+	b = uint64(buf[i])
+	i++
+	x += b << 42
+	if b&0x80 == 0 {
+		goto done
+	}
+	x -= 0x80 << 42
+
+	b = uint64(buf[i])
+	i++
+	x += b << 49
+	if b&0x80 == 0 {
+		goto done
+	}
+	x -= 0x80 << 49
+
+	b = uint64(buf[i])
+	i++
+	x += b << 56
+	if b&0x80 == 0 {
+		goto done
+	}
+	x -= 0x80 << 56
+
+	b = uint64(buf[i])
+	i++
+	x += b << 63
+	if b&0x80 == 0 {
+		goto done
+	}
+	// x -= 0x80 << 63 // Always zero.
+
+	return 0, errOverflow
+
+done:
+	p.index = i
+	return x, nil
+}
+
 // DecodeFixed64 reads a 64-bit integer from the Buffer.
 // This is the format for the
 // fixed64, sfixed64, and double protocol buffer types.
@@ -173,9 +261,6 @@ func (p *Buffer) DecodeZigzag32() (x uint64, err error) {
 	return
 }
 
-// These are not ValueDecoders: they produce an array of bytes or a string.
-// bytes, embedded messages
-
 // DecodeRawBytes reads a count-delimited byte buffer from the Buffer.
 // This is the format used for the bytes protocol buffer
 // type and for embedded messages.
@@ -217,81 +302,29 @@ func (p *Buffer) DecodeStringBytes() (s string, err error) {
 	return string(buf), nil
 }
 
-// Skip the next item in the buffer. Its wire type is decoded and presented as an argument.
-// If the protocol buffer has extensions, and the field matches, add it as an extension.
-// Otherwise, if the XXX_unrecognized field exists, append the skipped data there.
-func (o *Buffer) skipAndSave(t reflect.Type, tag, wire int, base structPointer, unrecField field) error {
-	oi := o.index
-
-	err := o.skip(t, tag, wire)
-	if err != nil {
-		return err
-	}
-
-	if !unrecField.IsValid() {
-		return nil
-	}
-
-	ptr := structPointer_Bytes(base, unrecField)
-
-	// Add the skipped field to struct field
-	obuf := o.buf
-
-	o.buf = *ptr
-	o.EncodeVarint(uint64(tag<<3 | wire))
-	*ptr = append(o.buf, obuf[oi:o.index]...)
-
-	o.buf = obuf
-
-	return nil
-}
-
-// Skip the next item in the buffer. Its wire type is decoded and presented as an argument.
-func (o *Buffer) skip(t reflect.Type, tag, wire int) error {
-
-	var u uint64
-	var err error
-
-	switch wire {
-	case WireVarint:
-		_, err = o.DecodeVarint()
-	case WireFixed64:
-		_, err = o.DecodeFixed64()
-	case WireBytes:
-		_, err = o.DecodeRawBytes(false)
-	case WireFixed32:
-		_, err = o.DecodeFixed32()
-	case WireStartGroup:
-		for {
-			u, err = o.DecodeVarint()
-			if err != nil {
-				break
-			}
-			fwire := int(u & 0x7)
-			if fwire == WireEndGroup {
-				break
-			}
-			ftag := int(u >> 3)
-			err = o.skip(t, ftag, fwire)
-			if err != nil {
-				break
-			}
-		}
-	default:
-		err = fmt.Errorf("proto: can't skip unknown wire type %d for %s", wire, t)
-	}
-	return err
-}
-
 // Unmarshaler is the interface representing objects that can
-// unmarshal themselves.  The method should reset the receiver before
-// decoding starts.  The argument points to data that may be
+// unmarshal themselves.  The argument points to data that may be
 // overwritten, so implementations should not keep references to the
 // buffer.
+// Unmarshal implementations should not clear the receiver.
+// Any unmarshaled data should be merged into the receiver.
+// Callers of Unmarshal that do not want to retain existing data
+// should Reset the receiver before calling Unmarshal.
 type Unmarshaler interface {
 	Unmarshal([]byte) error
 }
 
+// newUnmarshaler is the interface representing objects that can
+// unmarshal themselves. The semantics are identical to Unmarshaler.
+//
+// This exists to support protoc-gen-go generated messages.
+// The proto package will stop type-asserting to this interface in the future.
+//
+// DO NOT DEPEND ON THIS.
+type newUnmarshaler interface {
+	XXX_Unmarshal([]byte) error
+}
+
 // Unmarshal parses the protocol buffer representation in buf and places the
 // decoded result in pb.  If the struct underlying pb does not match
 // the data in buf, the results can be unpredictable.
@@ -301,7 +334,13 @@ type Unmarshaler interface {
 // to preserve and append to existing data.
 func Unmarshal(buf []byte, pb Message) error {
 	pb.Reset()
-	return UnmarshalMerge(buf, pb)
+	if u, ok := pb.(newUnmarshaler); ok {
+		return u.XXX_Unmarshal(buf)
+	}
+	if u, ok := pb.(Unmarshaler); ok {
+		return u.Unmarshal(buf)
+	}
+	return NewBuffer(buf).Unmarshal(pb)
 }
 
 // UnmarshalMerge parses the protocol buffer representation in buf and
@@ -311,8 +350,16 @@ func Unmarshal(buf []byte, pb Message) error {
 // UnmarshalMerge merges into existing data in pb.
 // Most code should use Unmarshal instead.
 func UnmarshalMerge(buf []byte, pb Message) error {
-	// If the object can unmarshal itself, let it.
+	if u, ok := pb.(newUnmarshaler); ok {
+		return u.XXX_Unmarshal(buf)
+	}
 	if u, ok := pb.(Unmarshaler); ok {
+		// NOTE: The history of proto have unfortunately been inconsistent
+		// whether Unmarshaler should or should not implicitly clear itself.
+		// Some implementations do, most do not.
+		// Thus, calling this here may or may not do what people want.
+		//
+		// See https://github.com/golang/protobuf/issues/424
 		return u.Unmarshal(buf)
 	}
 	return NewBuffer(buf).Unmarshal(pb)
@@ -328,541 +375,54 @@ func (p *Buffer) DecodeMessage(pb Message) error {
 }
 
 // DecodeGroup reads a tag-delimited group from the Buffer.
+// StartGroup tag is already consumed. This function consumes
+// EndGroup tag.
 func (p *Buffer) DecodeGroup(pb Message) error {
-	typ, base, err := getbase(pb)
-	if err != nil {
-		return err
+	b := p.buf[p.index:]
+	x, y := findEndGroup(b)
+	if x < 0 {
+		return io.ErrUnexpectedEOF
 	}
-	return p.unmarshalType(typ.Elem(), GetProperties(typ.Elem()), true, base)
+	err := Unmarshal(b[:x], pb)
+	p.index += y
+	return err
 }
 
 // Unmarshal parses the protocol buffer representation in the
 // Buffer and places the decoded result in pb.  If the struct
 // underlying pb does not match the data in the buffer, the results can be
 // unpredictable.
+//
+// Unlike proto.Unmarshal, this does not reset pb before starting to unmarshal.
 func (p *Buffer) Unmarshal(pb Message) error {
 	// If the object can unmarshal itself, let it.
+	if u, ok := pb.(newUnmarshaler); ok {
+		err := u.XXX_Unmarshal(p.buf[p.index:])
+		p.index = len(p.buf)
+		return err
+	}
 	if u, ok := pb.(Unmarshaler); ok {
+		// NOTE: The history of proto have unfortunately been inconsistent
+		// whether Unmarshaler should or should not implicitly clear itself.
+		// Some implementations do, most do not.
+		// Thus, calling this here may or may not do what people want.
+		//
+		// See https://github.com/golang/protobuf/issues/424
 		err := u.Unmarshal(p.buf[p.index:])
 		p.index = len(p.buf)
 		return err
 	}
 
-	typ, base, err := getbase(pb)
-	if err != nil {
-		return err
-	}
-
-	err = p.unmarshalType(typ.Elem(), GetProperties(typ.Elem()), false, base)
-
-	if collectStats {
-		stats.Decode++
-	}
-
-	return err
-}
-
-// unmarshalType does the work of unmarshaling a structure.
-func (o *Buffer) unmarshalType(st reflect.Type, prop *StructProperties, is_group bool, base structPointer) error {
-	var state errorState
-	required, reqFields := prop.reqCount, uint64(0)
-
-	var err error
-	for err == nil && o.index < len(o.buf) {
-		oi := o.index
-		var u uint64
-		u, err = o.DecodeVarint()
-		if err != nil {
-			break
-		}
-		wire := int(u & 0x7)
-		if wire == WireEndGroup {
-			if is_group {
-				return nil // input is satisfied
-			}
-			return fmt.Errorf("proto: %s: wiretype end group for non-group", st)
-		}
-		tag := int(u >> 3)
-		if tag <= 0 {
-			return fmt.Errorf("proto: %s: illegal tag %d (wire type %d)", st, tag, wire)
-		}
-		fieldnum, ok := prop.decoderTags.get(tag)
-		if !ok {
-			// Maybe it's an extension?
-			if prop.extendable {
-				if e := structPointer_Interface(base, st).(extendableProto); isExtensionField(e, int32(tag)) {
-					if err = o.skip(st, tag, wire); err == nil {
-						ext := e.ExtensionMap()[int32(tag)] // may be missing
-						ext.enc = append(ext.enc, o.buf[oi:o.index]...)
-						e.ExtensionMap()[int32(tag)] = ext
-					}
-					continue
-				}
-			}
-			// Maybe it's a oneof?
-			if prop.oneofUnmarshaler != nil {
-				m := structPointer_Interface(base, st).(Message)
-				// First return value indicates whether tag is a oneof field.
-				ok, err = prop.oneofUnmarshaler(m, tag, wire, o)
-				if err == ErrInternalBadWireType {
-					// Map the error to something more descriptive.
-					// Do the formatting here to save generated code space.
-					err = fmt.Errorf("bad wiretype for oneof field in %T", m)
-				}
-				if ok {
-					continue
-				}
-			}
-			err = o.skipAndSave(st, tag, wire, base, prop.unrecField)
-			continue
-		}
-		p := prop.Prop[fieldnum]
-
-		if p.dec == nil {
-			fmt.Fprintf(os.Stderr, "proto: no protobuf decoder for %s.%s\n", st, st.Field(fieldnum).Name)
-			continue
-		}
-		dec := p.dec
-		if wire != WireStartGroup && wire != p.WireType {
-			if wire == WireBytes && p.packedDec != nil {
-				// a packable field
-				dec = p.packedDec
-			} else {
-				err = fmt.Errorf("proto: bad wiretype for field %s.%s: got wiretype %d, want %d", st, st.Field(fieldnum).Name, wire, p.WireType)
-				continue
-			}
-		}
-		decErr := dec(o, p, base)
-		if decErr != nil && !state.shouldContinue(decErr, p) {
-			err = decErr
-		}
-		if err == nil && p.Required {
-			// Successfully decoded a required field.
-			if tag <= 64 {
-				// use bitmap for fields 1-64 to catch field reuse.
-				var mask uint64 = 1 << uint64(tag-1)
-				if reqFields&mask == 0 {
-					// new required field
-					reqFields |= mask
-					required--
-				}
-			} else {
-				// This is imprecise. It can be fooled by a required field
-				// with a tag > 64 that is encoded twice; that's very rare.
-				// A fully correct implementation would require allocating
-				// a data structure, which we would like to avoid.
-				required--
-			}
-		}
-	}
-	if err == nil {
-		if is_group {
-			return io.ErrUnexpectedEOF
-		}
-		if state.err != nil {
-			return state.err
-		}
-		if required > 0 {
-			// Not enough information to determine the exact field. If we use extra
-			// CPU, we could determine the field only if the missing required field
-			// has a tag <= 64 and we check reqFields.
-			return &RequiredNotSetError{"{Unknown}"}
-		}
-	}
-	return err
-}
-
-// Individual type decoders
-// For each,
-//	u is the decoded value,
-//	v is a pointer to the field (pointer) in the struct
-
-// Sizes of the pools to allocate inside the Buffer.
-// The goal is modest amortization and allocation
-// on at least 16-byte boundaries.
-const (
-	boolPoolSize   = 16
-	uint32PoolSize = 8
-	uint64PoolSize = 4
-)
-
-// Decode a bool.
-func (o *Buffer) dec_bool(p *Properties, base structPointer) error {
-	u, err := p.valDec(o)
-	if err != nil {
-		return err
-	}
-	if len(o.bools) == 0 {
-		o.bools = make([]bool, boolPoolSize)
-	}
-	o.bools[0] = u != 0
-	*structPointer_Bool(base, p.field) = &o.bools[0]
-	o.bools = o.bools[1:]
-	return nil
-}
-
-func (o *Buffer) dec_proto3_bool(p *Properties, base structPointer) error {
-	u, err := p.valDec(o)
-	if err != nil {
-		return err
-	}
-	*structPointer_BoolVal(base, p.field) = u != 0
-	return nil
-}
-
-// Decode an int32.
-func (o *Buffer) dec_int32(p *Properties, base structPointer) error {
-	u, err := p.valDec(o)
-	if err != nil {
-		return err
-	}
-	word32_Set(structPointer_Word32(base, p.field), o, uint32(u))
-	return nil
-}
-
-func (o *Buffer) dec_proto3_int32(p *Properties, base structPointer) error {
-	u, err := p.valDec(o)
-	if err != nil {
-		return err
-	}
-	word32Val_Set(structPointer_Word32Val(base, p.field), uint32(u))
-	return nil
-}
-
-// Decode an int64.
-func (o *Buffer) dec_int64(p *Properties, base structPointer) error {
-	u, err := p.valDec(o)
-	if err != nil {
-		return err
-	}
-	word64_Set(structPointer_Word64(base, p.field), o, u)
-	return nil
-}
-
-func (o *Buffer) dec_proto3_int64(p *Properties, base structPointer) error {
-	u, err := p.valDec(o)
-	if err != nil {
-		return err
-	}
-	word64Val_Set(structPointer_Word64Val(base, p.field), o, u)
-	return nil
-}
-
-// Decode a string.
-func (o *Buffer) dec_string(p *Properties, base structPointer) error {
-	s, err := o.DecodeStringBytes()
-	if err != nil {
-		return err
-	}
-	*structPointer_String(base, p.field) = &s
-	return nil
-}
-
-func (o *Buffer) dec_proto3_string(p *Properties, base structPointer) error {
-	s, err := o.DecodeStringBytes()
-	if err != nil {
-		return err
-	}
-	*structPointer_StringVal(base, p.field) = s
-	return nil
-}
-
-// Decode a slice of bytes ([]byte).
-func (o *Buffer) dec_slice_byte(p *Properties, base structPointer) error {
-	b, err := o.DecodeRawBytes(true)
-	if err != nil {
-		return err
-	}
-	*structPointer_Bytes(base, p.field) = b
-	return nil
-}
-
-// Decode a slice of bools ([]bool).
-func (o *Buffer) dec_slice_bool(p *Properties, base structPointer) error {
-	u, err := p.valDec(o)
-	if err != nil {
-		return err
-	}
-	v := structPointer_BoolSlice(base, p.field)
-	*v = append(*v, u != 0)
-	return nil
-}
-
-// Decode a slice of bools ([]bool) in packed format.
-func (o *Buffer) dec_slice_packed_bool(p *Properties, base structPointer) error {
-	v := structPointer_BoolSlice(base, p.field)
-
-	nn, err := o.DecodeVarint()
-	if err != nil {
-		return err
-	}
-	nb := int(nn) // number of bytes of encoded bools
-	fin := o.index + nb
-	if fin < o.index {
-		return errOverflow
-	}
-
-	y := *v
-	for o.index < fin {
-		u, err := p.valDec(o)
-		if err != nil {
-			return err
-		}
-		y = append(y, u != 0)
-	}
-
-	*v = y
-	return nil
-}
-
-// Decode a slice of int32s ([]int32).
-func (o *Buffer) dec_slice_int32(p *Properties, base structPointer) error {
-	u, err := p.valDec(o)
-	if err != nil {
-		return err
-	}
-	structPointer_Word32Slice(base, p.field).Append(uint32(u))
-	return nil
-}
-
-// Decode a slice of int32s ([]int32) in packed format.
-func (o *Buffer) dec_slice_packed_int32(p *Properties, base structPointer) error {
-	v := structPointer_Word32Slice(base, p.field)
-
-	nn, err := o.DecodeVarint()
-	if err != nil {
-		return err
-	}
-	nb := int(nn) // number of bytes of encoded int32s
-
-	fin := o.index + nb
-	if fin < o.index {
-		return errOverflow
-	}
-	for o.index < fin {
-		u, err := p.valDec(o)
-		if err != nil {
-			return err
-		}
-		v.Append(uint32(u))
-	}
-	return nil
-}
-
-// Decode a slice of int64s ([]int64).
-func (o *Buffer) dec_slice_int64(p *Properties, base structPointer) error {
-	u, err := p.valDec(o)
-	if err != nil {
-		return err
-	}
-
-	structPointer_Word64Slice(base, p.field).Append(u)
-	return nil
-}
-
-// Decode a slice of int64s ([]int64) in packed format.
-func (o *Buffer) dec_slice_packed_int64(p *Properties, base structPointer) error {
-	v := structPointer_Word64Slice(base, p.field)
-
-	nn, err := o.DecodeVarint()
-	if err != nil {
-		return err
-	}
-	nb := int(nn) // number of bytes of encoded int64s
-
-	fin := o.index + nb
-	if fin < o.index {
-		return errOverflow
-	}
-	for o.index < fin {
-		u, err := p.valDec(o)
-		if err != nil {
-			return err
-		}
-		v.Append(u)
-	}
-	return nil
-}
-
-// Decode a slice of strings ([]string).
-func (o *Buffer) dec_slice_string(p *Properties, base structPointer) error {
-	s, err := o.DecodeStringBytes()
-	if err != nil {
-		return err
-	}
-	v := structPointer_StringSlice(base, p.field)
-	*v = append(*v, s)
-	return nil
-}
-
-// Decode a slice of slice of bytes ([][]byte).
-func (o *Buffer) dec_slice_slice_byte(p *Properties, base structPointer) error {
-	b, err := o.DecodeRawBytes(true)
-	if err != nil {
-		return err
-	}
-	v := structPointer_BytesSlice(base, p.field)
-	*v = append(*v, b)
-	return nil
-}
-
-// Decode a map field.
-func (o *Buffer) dec_new_map(p *Properties, base structPointer) error {
-	raw, err := o.DecodeRawBytes(false)
-	if err != nil {
-		return err
-	}
-	oi := o.index       // index at the end of this map entry
-	o.index -= len(raw) // move buffer back to start of map entry
-
-	mptr := structPointer_NewAt(base, p.field, p.mtype) // *map[K]V
-	if mptr.Elem().IsNil() {
-		mptr.Elem().Set(reflect.MakeMap(mptr.Type().Elem()))
-	}
-	v := mptr.Elem() // map[K]V
-
-	// Prepare addressable doubly-indirect placeholders for the key and value types.
-	// See enc_new_map for why.
-	keyptr := reflect.New(reflect.PtrTo(p.mtype.Key())).Elem() // addressable *K
-	keybase := toStructPointer(keyptr.Addr())                  // **K
-
-	var valbase structPointer
-	var valptr reflect.Value
-	switch p.mtype.Elem().Kind() {
-	case reflect.Slice:
-		// []byte
-		var dummy []byte
-		valptr = reflect.ValueOf(&dummy)  // *[]byte
-		valbase = toStructPointer(valptr) // *[]byte
-	case reflect.Ptr:
-		// message; valptr is **Msg; need to allocate the intermediate pointer
-		valptr = reflect.New(reflect.PtrTo(p.mtype.Elem())).Elem() // addressable *V
-		valptr.Set(reflect.New(valptr.Type().Elem()))
-		valbase = toStructPointer(valptr)
-	default:
-		// everything else
-		valptr = reflect.New(reflect.PtrTo(p.mtype.Elem())).Elem() // addressable *V
-		valbase = toStructPointer(valptr.Addr())                   // **V
-	}
-
-	// Decode.
-	// This parses a restricted wire format, namely the encoding of a message
-	// with two fields. See enc_new_map for the format.
-	for o.index < oi {
-		// tagcode for key and value properties are always a single byte
-		// because they have tags 1 and 2.
-		tagcode := o.buf[o.index]
-		o.index++
-		switch tagcode {
-		case p.mkeyprop.tagcode[0]:
-			if err := p.mkeyprop.dec(o, p.mkeyprop, keybase); err != nil {
-				return err
-			}
-		case p.mvalprop.tagcode[0]:
-			if err := p.mvalprop.dec(o, p.mvalprop, valbase); err != nil {
-				return err
-			}
-		default:
-			// TODO: Should we silently skip this instead?
-			return fmt.Errorf("proto: bad map data tag %d", raw[0])
-		}
-	}
-	keyelem, valelem := keyptr.Elem(), valptr.Elem()
-	if !keyelem.IsValid() {
-		keyelem = reflect.Zero(p.mtype.Key())
-	}
-	if !valelem.IsValid() {
-		valelem = reflect.Zero(p.mtype.Elem())
-	}
-
-	v.SetMapIndex(keyelem, valelem)
-	return nil
-}
-
-// Decode a group.
-func (o *Buffer) dec_struct_group(p *Properties, base structPointer) error {
-	bas := structPointer_GetStructPointer(base, p.field)
-	if structPointer_IsNil(bas) {
-		// allocate new nested message
-		bas = toStructPointer(reflect.New(p.stype))
-		structPointer_SetStructPointer(base, p.field, bas)
-	}
-	return o.unmarshalType(p.stype, p.sprop, true, bas)
-}
-
-// Decode an embedded message.
-func (o *Buffer) dec_struct_message(p *Properties, base structPointer) (err error) {
-	raw, e := o.DecodeRawBytes(false)
-	if e != nil {
-		return e
-	}
-
-	bas := structPointer_GetStructPointer(base, p.field)
-	if structPointer_IsNil(bas) {
-		// allocate new nested message
-		bas = toStructPointer(reflect.New(p.stype))
-		structPointer_SetStructPointer(base, p.field, bas)
-	}
-
-	// If the object can unmarshal itself, let it.
-	if p.isUnmarshaler {
-		iv := structPointer_Interface(bas, p.stype)
-		return iv.(Unmarshaler).Unmarshal(raw)
-	}
-
-	obuf := o.buf
-	oi := o.index
-	o.buf = raw
-	o.index = 0
-
-	err = o.unmarshalType(p.stype, p.sprop, false, bas)
-	o.buf = obuf
-	o.index = oi
-
-	return err
-}
-
-// Decode a slice of embedded messages.
-func (o *Buffer) dec_slice_struct_message(p *Properties, base structPointer) error {
-	return o.dec_slice_struct(p, false, base)
-}
-
-// Decode a slice of embedded groups.
-func (o *Buffer) dec_slice_struct_group(p *Properties, base structPointer) error {
-	return o.dec_slice_struct(p, true, base)
-}
-
-// Decode a slice of structs ([]*struct).
-func (o *Buffer) dec_slice_struct(p *Properties, is_group bool, base structPointer) error {
-	v := reflect.New(p.stype)
-	bas := toStructPointer(v)
-	structPointer_StructPointerSlice(base, p.field).Append(bas)
-
-	if is_group {
-		err := o.unmarshalType(p.stype, p.sprop, is_group, bas)
-		return err
-	}
-
-	raw, err := o.DecodeRawBytes(false)
-	if err != nil {
-		return err
-	}
-
-	// If the object can unmarshal itself, let it.
-	if p.isUnmarshaler {
-		iv := v.Interface()
-		return iv.(Unmarshaler).Unmarshal(raw)
-	}
-
-	obuf := o.buf
-	oi := o.index
-	o.buf = raw
-	o.index = 0
-
-	err = o.unmarshalType(p.stype, p.sprop, is_group, bas)
-
-	o.buf = obuf
-	o.index = oi
-
+	// Slow workaround for messages that aren't Unmarshalers.
+	// This includes some hand-coded .pb.go files and
+	// bootstrap protos.
+	// TODO: fix all of those and then add Unmarshal to
+	// the Message interface. Then:
+	// The cast above and code below can be deleted.
+	// The old unmarshaler can be deleted.
+	// Clients can call Unmarshal directly (can already do that, actually).
+	var info InternalMessageInfo
+	err := info.Unmarshal(pb, p.buf[p.index:])
+	p.index = len(p.buf)
 	return err
 }