forked from FerretDB/FerretDB
/
op_msg.go
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/
op_msg.go
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// Copyright 2021 FerretDB Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package wire
import (
"encoding/binary"
"fmt"
"github.com/FerretDB/FerretDB/internal/bson2"
"github.com/FerretDB/FerretDB/internal/types"
"github.com/FerretDB/FerretDB/internal/util/debugbuild"
"github.com/FerretDB/FerretDB/internal/util/lazyerrors"
"github.com/FerretDB/FerretDB/internal/util/must"
)
// typesValidation, when true, enables validation of types in wire messages.
const typesValidation = true
// OpMsgSection is one or more sections contained in an OpMsg.
type OpMsgSection struct {
// The order of fields is weird to make the struct smaller due to alignment.
// The wire order is: kind, identifier, documents.
Identifier string
Documents []bson2.RawDocument
Kind byte
}
// MakeOpMsgSection creates [OpMsgSection] with a single document.
func MakeOpMsgSection(doc *types.Document) OpMsgSection {
raw := must.NotFail(must.NotFail(bson2.ConvertDocument(doc)).Encode())
return OpMsgSection{
Documents: []bson2.RawDocument{raw},
}
}
// OpMsg is the main wire protocol message type.
type OpMsg struct {
// The order of fields is weird to make the struct smaller due to alignment.
// The wire order is: flags, sections, optional checksum.
sections []OpMsgSection
Flags OpMsgFlags
checksum uint32
}
// NewOpMsg creates a message with a single section of kind 0 with a single raw document.
func NewOpMsg(raw bson2.RawDocument) (*OpMsg, error) {
var msg OpMsg
if err := msg.SetSections(OpMsgSection{Documents: []bson2.RawDocument{raw}}); err != nil {
return nil, lazyerrors.Error(err)
}
return &msg, nil
}
// checkSections checks given sections.
func checkSections(sections []OpMsgSection) error {
if len(sections) == 0 {
return lazyerrors.New("no sections")
}
var kind0Found bool
for _, s := range sections {
switch s.Kind {
case 0:
if kind0Found {
return lazyerrors.New("multiple kind 0 sections")
}
kind0Found = true
if s.Identifier != "" {
return lazyerrors.New("kind 0 section has identifier")
}
if len(s.Documents) != 1 {
return lazyerrors.Errorf("kind 0 section has %d documents", len(s.Documents))
}
case 1:
if s.Identifier == "" {
return lazyerrors.New("kind 1 section has no identifier")
}
default:
return lazyerrors.Errorf("unknown kind %d", s.Kind)
}
}
return nil
}
// Sections returns the sections of the OpMsg.
func (msg *OpMsg) Sections() []OpMsgSection {
return msg.sections
}
// SetSections sets sections of the OpMsg.
func (msg *OpMsg) SetSections(sections ...OpMsgSection) error {
if err := checkSections(sections); err != nil {
return lazyerrors.Error(err)
}
msg.sections = sections
if debugbuild.Enabled {
if err := msg.check(); err != nil {
return lazyerrors.Error(err)
}
}
if typesValidation {
if _, err := msg.Document(); err != nil {
return lazyerrors.Error(err)
}
}
return nil
}
// Document returns the value of msg as a [types.Document].
//
// All sections are merged together.
func (msg *OpMsg) Document() (*types.Document, error) {
if err := checkSections(msg.sections); err != nil {
return nil, lazyerrors.Error(err)
}
docs := make([]*types.Document, 0, len(msg.sections))
// Sections of kind 1 may come before the section of kind 0,
// but the command is defined by the first key in the section of kind 0.
// Reorder documents to set keys in the right order.
for _, section := range msg.sections {
if section.Kind != 0 {
continue
}
doc, err := section.Documents[0].Convert()
if err != nil {
return nil, lazyerrors.Error(err)
}
docs = append(docs, doc)
}
for _, section := range msg.sections {
if section.Kind == 0 {
continue
}
a := types.MakeArray(len(section.Documents))
for _, d := range section.Documents {
doc, err := d.Convert()
if err != nil {
return nil, lazyerrors.Error(err)
}
a.Append(doc)
}
docs = append(docs, must.NotFail(types.NewDocument(section.Identifier, a)))
}
res := types.MakeDocument(2)
for _, doc := range docs {
values := doc.Values()
for i, k := range doc.Keys() {
res.Set(k, values[i])
}
}
if err := validateValue(res); err != nil {
res.Remove("lsid") // to simplify error message
return nil, newValidationError(fmt.Errorf("wire.OpMsg.Document: validation failed for %v with: %v",
types.FormatAnyValue(res),
err,
))
}
return res, nil
}
// RawSections returns the value of section with kind 0 and the value of all sections with kind 1.
func (msg *OpMsg) RawSections() (bson2.RawDocument, []byte) {
var spec bson2.RawDocument
var seq []byte
for _, s := range msg.Sections() {
switch s.Kind {
case 0:
spec = s.Documents[0]
case 1:
for _, d := range s.Documents {
seq = append(seq, d...)
}
}
}
return spec, seq
}
// RawDocument returns the value of msg as a [bson2.RawDocument].
//
// The error is returned if msg contains anything other than a single section of kind 0
// with a single document.
func (msg *OpMsg) RawDocument() (bson2.RawDocument, error) {
if err := checkSections(msg.sections); err != nil {
return nil, err
}
s := msg.sections[0]
if s.Kind != 0 || s.Identifier != "" {
return nil, lazyerrors.Errorf(`expected section 0/"", got %d/%q`, s.Kind, s.Identifier)
}
return s.Documents[0], nil
}
func (msg *OpMsg) msgbody() {}
// check implements [MsgBody] interface.
func (msg *OpMsg) check() error {
for _, s := range msg.sections {
for _, d := range s.Documents {
if _, err := d.DecodeDeep(); err != nil {
return lazyerrors.Error(err)
}
}
}
return nil
}
// UnmarshalBinaryNocopy implements [MsgBody] interface.
func (msg *OpMsg) UnmarshalBinaryNocopy(b []byte) error {
if len(b) < 6 {
return lazyerrors.Errorf("len=%d", len(b))
}
msg.Flags = OpMsgFlags(binary.LittleEndian.Uint32(b[0:4]))
offset := 4
for {
var section OpMsgSection
section.Kind = b[offset]
offset++
switch section.Kind {
case 0:
l, err := bson2.FindRaw(b[offset:])
if err != nil {
return lazyerrors.Error(err)
}
section.Documents = []bson2.RawDocument{b[offset : offset+l]}
offset += l
case 1:
if len(b) < offset+4 {
return lazyerrors.Errorf("len(b) = %d, offset = %d", len(b), offset)
}
secSize := int(binary.LittleEndian.Uint32(b[offset:offset+4])) - 4
if secSize < 5 {
return lazyerrors.Errorf("size = %d", secSize)
}
offset += 4
var err error
if len(b) < offset {
return lazyerrors.Errorf("len(b) = %d, offset = %d", len(b), offset)
}
section.Identifier, err = bson2.DecodeCString(b[offset:])
if err != nil {
return lazyerrors.Error(err)
}
offset += bson2.SizeCString(section.Identifier)
secSize -= bson2.SizeCString(section.Identifier)
for secSize != 0 {
if secSize < 0 {
return lazyerrors.Errorf("size = %d", secSize)
}
if len(b) < offset {
return lazyerrors.Errorf("len(b) = %d, offset = %d", len(b), offset)
}
l, err := bson2.FindRaw(b[offset:])
if err != nil {
return lazyerrors.Error(err)
}
section.Documents = append(section.Documents, b[offset:offset+l])
offset += l
secSize -= l
}
default:
return lazyerrors.Errorf("kind is %d", section.Kind)
}
msg.sections = append(msg.sections, section)
if msg.Flags.FlagSet(OpMsgChecksumPresent) {
if offset == len(b)-4 {
break
}
} else {
if offset == len(b) {
break
}
}
}
if msg.Flags.FlagSet(OpMsgChecksumPresent) {
// Move checksum validation here. It needs header data to be available.
// TODO https://github.com/FerretDB/FerretDB/issues/2690
msg.checksum = binary.LittleEndian.Uint32(b[offset:])
}
if err := checkSections(msg.sections); err != nil {
return lazyerrors.Error(err)
}
if debugbuild.Enabled {
if err := msg.check(); err != nil {
return lazyerrors.Error(err)
}
}
if typesValidation {
if _, err := msg.Document(); err != nil {
return lazyerrors.Error(err)
}
}
return nil
}
// MarshalBinary writes an OpMsg to a byte array.
func (msg *OpMsg) MarshalBinary() ([]byte, error) {
if err := checkSections(msg.sections); err != nil {
return nil, lazyerrors.Error(err)
}
if debugbuild.Enabled {
if err := msg.check(); err != nil {
return nil, lazyerrors.Error(err)
}
}
if typesValidation {
if _, err := msg.Document(); err != nil {
return nil, lazyerrors.Error(err)
}
}
b := make([]byte, 4, 16)
binary.LittleEndian.PutUint32(b, uint32(msg.Flags))
for _, section := range msg.sections {
b = append(b, section.Kind)
switch section.Kind {
case 0:
b = append(b, section.Documents[0]...)
case 1:
sec := make([]byte, bson2.SizeCString(section.Identifier))
bson2.EncodeCString(sec, section.Identifier)
for _, doc := range section.Documents {
sec = append(sec, doc...)
}
var size [4]byte
binary.LittleEndian.PutUint32(size[:], uint32(len(sec)+4))
b = append(b, size[:]...)
b = append(b, sec...)
default:
return nil, lazyerrors.Errorf("kind is %d", section.Kind)
}
}
if msg.Flags.FlagSet(OpMsgChecksumPresent) {
// Calculate checksum before writing it. It needs header data to be ready and available here.
// TODO https://github.com/FerretDB/FerretDB/issues/2690
var checksum [4]byte
binary.LittleEndian.PutUint32(checksum[:], msg.checksum)
b = append(b, checksum[:]...)
}
return b, nil
}
// logMessage returns a string representation for logging.
func (msg *OpMsg) logMessage(block bool) string {
if msg == nil {
return "<nil>"
}
m := must.NotFail(bson2.NewDocument(
"FlagBits", msg.Flags.String(),
"Checksum", int64(msg.checksum),
))
sections := bson2.MakeArray(len(msg.sections))
for _, section := range msg.sections {
s := must.NotFail(bson2.NewDocument(
"Kind", int32(section.Kind),
))
switch section.Kind {
case 0:
doc, err := section.Documents[0].DecodeDeep()
if err == nil {
must.NoError(s.Add("Document", doc))
} else {
must.NoError(s.Add("DocumentError", err.Error()))
}
case 1:
must.NoError(s.Add("Identifier", section.Identifier))
docs := bson2.MakeArray(len(section.Documents))
for _, d := range section.Documents {
doc, err := d.DecodeDeep()
if err == nil {
must.NoError(docs.Add(doc))
} else {
must.NoError(docs.Add(must.NotFail(bson2.NewDocument("error", err.Error()))))
}
}
must.NoError(s.Add("Documents", docs))
default:
panic(fmt.Sprintf("unknown kind %d", section.Kind))
}
must.NoError(sections.Add(s))
}
must.NoError(m.Add("Sections", sections))
if block {
return m.LogMessageBlock()
}
return m.LogMessage()
}
// String returns a string representation for logging.
func (msg *OpMsg) String() string {
return msg.logMessage(false)
}
// StringBlock returns an indented string representation for logging.
func (msg *OpMsg) StringBlock() string {
return msg.logMessage(true)
}
// check interfaces
var (
_ MsgBody = (*OpMsg)(nil)
)