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// 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 (
"fmt"
"reflect"
"sort"
"google.golang.org/protobuf/encoding/protowire"
"google.golang.org/protobuf/internal/encoding/messageset"
"google.golang.org/protobuf/internal/order"
pref "google.golang.org/protobuf/reflect/protoreflect"
piface "google.golang.org/protobuf/runtime/protoiface"
)
// coderMessageInfo contains per-message information used by the fast-path functions.
// This is a different type from MessageInfo to keep MessageInfo as general-purpose as
// possible.
type coderMessageInfo struct {
methods piface.Methods
orderedCoderFields []*coderFieldInfo
denseCoderFields []*coderFieldInfo
coderFields map[protowire.Number]*coderFieldInfo
sizecacheOffset offset
unknownOffset offset
unknownPtrKind bool
extensionOffset offset
needsInitCheck bool
isMessageSet bool
numRequiredFields uint8
}
type coderFieldInfo struct {
funcs pointerCoderFuncs // fast-path per-field functions
mi *MessageInfo // field's message
ft reflect.Type
validation validationInfo // information used by message validation
num pref.FieldNumber // field number
offset offset // struct field offset
wiretag uint64 // field tag (number + wire type)
tagsize int // size of the varint-encoded tag
isPointer bool // true if IsNil may be called on the struct field
isRequired bool // true if field is required
}
func (mi *MessageInfo) makeCoderMethods(t reflect.Type, si structInfo) {
mi.sizecacheOffset = invalidOffset
mi.unknownOffset = invalidOffset
mi.extensionOffset = invalidOffset
if si.sizecacheOffset.IsValid() && si.sizecacheType == sizecacheType {
mi.sizecacheOffset = si.sizecacheOffset
}
if si.unknownOffset.IsValid() && (si.unknownType == unknownFieldsAType || si.unknownType == unknownFieldsBType) {
mi.unknownOffset = si.unknownOffset
mi.unknownPtrKind = si.unknownType.Kind() == reflect.Ptr
}
if si.extensionOffset.IsValid() && si.extensionType == extensionFieldsType {
mi.extensionOffset = si.extensionOffset
}
mi.coderFields = make(map[protowire.Number]*coderFieldInfo)
fields := mi.Desc.Fields()
preallocFields := make([]coderFieldInfo, fields.Len())
for i := 0; i < fields.Len(); i++ {
fd := fields.Get(i)
fs := si.fieldsByNumber[fd.Number()]
isOneof := fd.ContainingOneof() != nil && !fd.ContainingOneof().IsSynthetic()
if isOneof {
fs = si.oneofsByName[fd.ContainingOneof().Name()]
}
ft := fs.Type
var wiretag uint64
if !fd.IsPacked() {
wiretag = protowire.EncodeTag(fd.Number(), wireTypes[fd.Kind()])
} else {
wiretag = protowire.EncodeTag(fd.Number(), protowire.BytesType)
}
var fieldOffset offset
var funcs pointerCoderFuncs
var childMessage *MessageInfo
switch {
case ft == nil:
// This never occurs for generated message types.
// It implies that a hand-crafted type has missing Go fields
// for specific protobuf message fields.
funcs = pointerCoderFuncs{
size: func(p pointer, f *coderFieldInfo, opts marshalOptions) int {
return 0
},
marshal: func(b []byte, p pointer, f *coderFieldInfo, opts marshalOptions) ([]byte, error) {
return nil, nil
},
unmarshal: func(b []byte, p pointer, wtyp protowire.Type, f *coderFieldInfo, opts unmarshalOptions) (unmarshalOutput, error) {
panic("missing Go struct field for " + string(fd.FullName()))
},
isInit: func(p pointer, f *coderFieldInfo) error {
panic("missing Go struct field for " + string(fd.FullName()))
},
merge: func(dst, src pointer, f *coderFieldInfo, opts mergeOptions) {
panic("missing Go struct field for " + string(fd.FullName()))
},
}
case isOneof:
fieldOffset = offsetOf(fs, mi.Exporter)
case fd.IsWeak():
fieldOffset = si.weakOffset
funcs = makeWeakMessageFieldCoder(fd)
default:
fieldOffset = offsetOf(fs, mi.Exporter)
childMessage, funcs = fieldCoder(fd, ft)
}
cf := &preallocFields[i]
*cf = coderFieldInfo{
num: fd.Number(),
offset: fieldOffset,
wiretag: wiretag,
ft: ft,
tagsize: protowire.SizeVarint(wiretag),
funcs: funcs,
mi: childMessage,
validation: newFieldValidationInfo(mi, si, fd, ft),
isPointer: fd.Cardinality() == pref.Repeated || fd.HasPresence(),
isRequired: fd.Cardinality() == pref.Required,
}
mi.orderedCoderFields = append(mi.orderedCoderFields, cf)
mi.coderFields[cf.num] = cf
}
for i, oneofs := 0, mi.Desc.Oneofs(); i < oneofs.Len(); i++ {
if od := oneofs.Get(i); !od.IsSynthetic() {
mi.initOneofFieldCoders(od, si)
}
}
if messageset.IsMessageSet(mi.Desc) {
if !mi.extensionOffset.IsValid() {
panic(fmt.Sprintf("%v: MessageSet with no extensions field", mi.Desc.FullName()))
}
if !mi.unknownOffset.IsValid() {
panic(fmt.Sprintf("%v: MessageSet with no unknown field", mi.Desc.FullName()))
}
mi.isMessageSet = true
}
sort.Slice(mi.orderedCoderFields, func(i, j int) bool {
return mi.orderedCoderFields[i].num < mi.orderedCoderFields[j].num
})
var maxDense pref.FieldNumber
for _, cf := range mi.orderedCoderFields {
if cf.num >= 16 && cf.num >= 2*maxDense {
break
}
maxDense = cf.num
}
mi.denseCoderFields = make([]*coderFieldInfo, maxDense+1)
for _, cf := range mi.orderedCoderFields {
if int(cf.num) >= len(mi.denseCoderFields) {
break
}
mi.denseCoderFields[cf.num] = cf
}
// To preserve compatibility with historic wire output, marshal oneofs last.
if mi.Desc.Oneofs().Len() > 0 {
sort.Slice(mi.orderedCoderFields, func(i, j int) bool {
fi := fields.ByNumber(mi.orderedCoderFields[i].num)
fj := fields.ByNumber(mi.orderedCoderFields[j].num)
return order.LegacyFieldOrder(fi, fj)
})
}
mi.needsInitCheck = needsInitCheck(mi.Desc)
if mi.methods.Marshal == nil && mi.methods.Size == nil {
mi.methods.Flags |= piface.SupportMarshalDeterministic
mi.methods.Marshal = mi.marshal
mi.methods.Size = mi.size
}
if mi.methods.Unmarshal == nil {
mi.methods.Flags |= piface.SupportUnmarshalDiscardUnknown
mi.methods.Unmarshal = mi.unmarshal
}
if mi.methods.CheckInitialized == nil {
mi.methods.CheckInitialized = mi.checkInitialized
}
if mi.methods.Merge == nil {
mi.methods.Merge = mi.merge
}
}
// getUnknownBytes returns a *[]byte for the unknown fields.
// It is the caller's responsibility to check whether the pointer is nil.
// This function is specially designed to be inlineable.
func (mi *MessageInfo) getUnknownBytes(p pointer) *[]byte {
if mi.unknownPtrKind {
return *p.Apply(mi.unknownOffset).BytesPtr()
} else {
return p.Apply(mi.unknownOffset).Bytes()
}
}
// mutableUnknownBytes returns a *[]byte for the unknown fields.
// The returned pointer is guaranteed to not be nil.
func (mi *MessageInfo) mutableUnknownBytes(p pointer) *[]byte {
if mi.unknownPtrKind {
bp := p.Apply(mi.unknownOffset).BytesPtr()
if *bp == nil {
*bp = new([]byte)
}
return *bp
} else {
return p.Apply(mi.unknownOffset).Bytes()
}
}