mirror of
https://github.com/protocolbuffers/protobuf-go.git
synced 2025-01-01 03:14:16 +00:00
5d63473da8
This CL adds runtime support for unknown fields to be represented as *[]byte in addition to the current representation as []byte. This CL does not change generated code to use *[]byte. Comparison between using *[]byte and []byte: • Every message supports unknown fields, so use of []byte expands a message size by 24B (for 64-bit systems). In contrast, *[]byte only expands a message by 8B. This has significant memory implications for small messages. • If unknown fields are encountered, *[]byte has extra overhead allocating the 24B slice header. However, it is assumed that messages rarely see any unknown fields at runtime, or generally do so for a temporary period of time. Change-Id: I81935e4ea7394166e61ff4579f76f59fa792dfc9 Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/244937 Reviewed-by: Damien Neil <dneil@google.com>
124 lines
3.2 KiB
Go
124 lines
3.2 KiB
Go
// Copyright 2019 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package impl
|
|
|
|
import (
|
|
"sort"
|
|
|
|
"google.golang.org/protobuf/encoding/protowire"
|
|
"google.golang.org/protobuf/internal/encoding/messageset"
|
|
"google.golang.org/protobuf/internal/errors"
|
|
"google.golang.org/protobuf/internal/flags"
|
|
)
|
|
|
|
func sizeMessageSet(mi *MessageInfo, p pointer, opts marshalOptions) (size int) {
|
|
if !flags.ProtoLegacy {
|
|
return 0
|
|
}
|
|
|
|
ext := *p.Apply(mi.extensionOffset).Extensions()
|
|
for _, x := range ext {
|
|
xi := getExtensionFieldInfo(x.Type())
|
|
if xi.funcs.size == nil {
|
|
continue
|
|
}
|
|
num, _ := protowire.DecodeTag(xi.wiretag)
|
|
size += messageset.SizeField(num)
|
|
size += xi.funcs.size(x.Value(), protowire.SizeTag(messageset.FieldMessage), opts)
|
|
}
|
|
|
|
if u := mi.getUnknownBytes(p); u != nil {
|
|
size += messageset.SizeUnknown(*u)
|
|
}
|
|
|
|
return size
|
|
}
|
|
|
|
func marshalMessageSet(mi *MessageInfo, b []byte, p pointer, opts marshalOptions) ([]byte, error) {
|
|
if !flags.ProtoLegacy {
|
|
return b, errors.New("no support for message_set_wire_format")
|
|
}
|
|
|
|
ext := *p.Apply(mi.extensionOffset).Extensions()
|
|
switch len(ext) {
|
|
case 0:
|
|
case 1:
|
|
// Fast-path for one extension: Don't bother sorting the keys.
|
|
for _, x := range ext {
|
|
var err error
|
|
b, err = marshalMessageSetField(mi, b, x, opts)
|
|
if err != nil {
|
|
return b, err
|
|
}
|
|
}
|
|
default:
|
|
// Sort the keys to provide a deterministic encoding.
|
|
// Not sure this is required, but the old code does it.
|
|
keys := make([]int, 0, len(ext))
|
|
for k := range ext {
|
|
keys = append(keys, int(k))
|
|
}
|
|
sort.Ints(keys)
|
|
for _, k := range keys {
|
|
var err error
|
|
b, err = marshalMessageSetField(mi, b, ext[int32(k)], opts)
|
|
if err != nil {
|
|
return b, err
|
|
}
|
|
}
|
|
}
|
|
|
|
if u := mi.getUnknownBytes(p); u != nil {
|
|
var err error
|
|
b, err = messageset.AppendUnknown(b, *u)
|
|
if err != nil {
|
|
return b, err
|
|
}
|
|
}
|
|
|
|
return b, nil
|
|
}
|
|
|
|
func marshalMessageSetField(mi *MessageInfo, b []byte, x ExtensionField, opts marshalOptions) ([]byte, error) {
|
|
xi := getExtensionFieldInfo(x.Type())
|
|
num, _ := protowire.DecodeTag(xi.wiretag)
|
|
b = messageset.AppendFieldStart(b, num)
|
|
b, err := xi.funcs.marshal(b, x.Value(), protowire.EncodeTag(messageset.FieldMessage, protowire.BytesType), opts)
|
|
if err != nil {
|
|
return b, err
|
|
}
|
|
b = messageset.AppendFieldEnd(b)
|
|
return b, nil
|
|
}
|
|
|
|
func unmarshalMessageSet(mi *MessageInfo, b []byte, p pointer, opts unmarshalOptions) (out unmarshalOutput, err error) {
|
|
if !flags.ProtoLegacy {
|
|
return out, errors.New("no support for message_set_wire_format")
|
|
}
|
|
|
|
ep := p.Apply(mi.extensionOffset).Extensions()
|
|
if *ep == nil {
|
|
*ep = make(map[int32]ExtensionField)
|
|
}
|
|
ext := *ep
|
|
initialized := true
|
|
err = messageset.Unmarshal(b, true, func(num protowire.Number, v []byte) error {
|
|
o, err := mi.unmarshalExtension(v, num, protowire.BytesType, ext, opts)
|
|
if err == errUnknown {
|
|
u := mi.mutableUnknownBytes(p)
|
|
*u = protowire.AppendTag(*u, num, protowire.BytesType)
|
|
*u = append(*u, v...)
|
|
return nil
|
|
}
|
|
if !o.initialized {
|
|
initialized = false
|
|
}
|
|
return err
|
|
})
|
|
out.n = len(b)
|
|
out.initialized = initialized
|
|
return out, err
|
|
}
|