protobuf-go/internal/impl/message_reflect_field.go
Joe Tsai fd528ff53f internal/impl: unexport Unwrapper
This interface is only ever used within the impl package.
Unexport it to avoid potential abuse by users.

Change-Id: I58d0cc2e8cb01c8c9d36cdec469c8d2196c4f836
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/193197
Reviewed-by: Damien Neil <dneil@google.com>
2019-09-05 06:07:39 +00:00

442 lines
11 KiB
Go

// Copyright 2018 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"
"math"
"reflect"
"sync"
"google.golang.org/protobuf/internal/flags"
pref "google.golang.org/protobuf/reflect/protoreflect"
preg "google.golang.org/protobuf/reflect/protoregistry"
piface "google.golang.org/protobuf/runtime/protoiface"
)
type fieldInfo struct {
fieldDesc pref.FieldDescriptor
// These fields are used for protobuf reflection support.
has func(pointer) bool
clear func(pointer)
get func(pointer) pref.Value
set func(pointer, pref.Value)
mutable func(pointer) pref.Value
newMessage func() pref.Message
newField func() pref.Value
}
func fieldInfoForOneof(fd pref.FieldDescriptor, fs reflect.StructField, x exporter, ot reflect.Type) fieldInfo {
ft := fs.Type
if ft.Kind() != reflect.Interface {
panic(fmt.Sprintf("invalid type: got %v, want interface kind", ft))
}
if ot.Kind() != reflect.Struct {
panic(fmt.Sprintf("invalid type: got %v, want struct kind", ot))
}
if !reflect.PtrTo(ot).Implements(ft) {
panic(fmt.Sprintf("invalid type: %v does not implement %v", ot, ft))
}
conv := NewConverter(ot.Field(0).Type, fd)
isMessage := fd.Message() != nil
// TODO: Implement unsafe fast path?
fieldOffset := offsetOf(fs, x)
return fieldInfo{
// NOTE: The logic below intentionally assumes that oneof fields are
// well-formatted. That is, the oneof interface never contains a
// typed nil pointer to one of the wrapper structs.
fieldDesc: fd,
has: func(p pointer) bool {
if p.IsNil() {
return false
}
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if rv.IsNil() || rv.Elem().Type().Elem() != ot || rv.Elem().IsNil() {
return false
}
return true
},
clear: func(p pointer) {
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if rv.IsNil() || rv.Elem().Type().Elem() != ot {
// NOTE: We intentionally don't check for rv.Elem().IsNil()
// so that (*OneofWrapperType)(nil) gets cleared to nil.
return
}
rv.Set(reflect.Zero(rv.Type()))
},
get: func(p pointer) pref.Value {
if p.IsNil() {
return conv.Zero()
}
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if rv.IsNil() || rv.Elem().Type().Elem() != ot || rv.Elem().IsNil() {
return conv.Zero()
}
rv = rv.Elem().Elem().Field(0)
return conv.PBValueOf(rv)
},
set: func(p pointer, v pref.Value) {
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if rv.IsNil() || rv.Elem().Type().Elem() != ot || rv.Elem().IsNil() {
rv.Set(reflect.New(ot))
}
rv = rv.Elem().Elem().Field(0)
rv.Set(conv.GoValueOf(v))
},
mutable: func(p pointer) pref.Value {
if !isMessage {
panic("invalid Mutable on field with non-composite type")
}
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if rv.IsNil() || rv.Elem().Type().Elem() != ot || rv.Elem().IsNil() {
rv.Set(reflect.New(ot))
}
rv = rv.Elem().Elem().Field(0)
if rv.IsNil() {
rv.Set(conv.GoValueOf(pref.ValueOf(conv.New().Message())))
}
return conv.PBValueOf(rv)
},
newMessage: func() pref.Message {
return conv.New().Message()
},
newField: func() pref.Value {
return conv.New()
},
}
}
func fieldInfoForMap(fd pref.FieldDescriptor, fs reflect.StructField, x exporter) fieldInfo {
ft := fs.Type
if ft.Kind() != reflect.Map {
panic(fmt.Sprintf("invalid type: got %v, want map kind", ft))
}
conv := NewConverter(ft, fd)
// TODO: Implement unsafe fast path?
fieldOffset := offsetOf(fs, x)
return fieldInfo{
fieldDesc: fd,
has: func(p pointer) bool {
if p.IsNil() {
return false
}
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
return rv.Len() > 0
},
clear: func(p pointer) {
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
rv.Set(reflect.Zero(rv.Type()))
},
get: func(p pointer) pref.Value {
if p.IsNil() {
return conv.Zero()
}
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
return conv.PBValueOf(rv)
},
set: func(p pointer, v pref.Value) {
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
rv.Set(conv.GoValueOf(v))
},
mutable: func(p pointer) pref.Value {
v := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if v.IsNil() {
v.Set(reflect.MakeMap(fs.Type))
}
return conv.PBValueOf(v)
},
newField: func() pref.Value {
return conv.New()
},
}
}
func fieldInfoForList(fd pref.FieldDescriptor, fs reflect.StructField, x exporter) fieldInfo {
ft := fs.Type
if ft.Kind() != reflect.Slice {
panic(fmt.Sprintf("invalid type: got %v, want slice kind", ft))
}
conv := NewConverter(reflect.PtrTo(ft), fd)
// TODO: Implement unsafe fast path?
fieldOffset := offsetOf(fs, x)
return fieldInfo{
fieldDesc: fd,
has: func(p pointer) bool {
if p.IsNil() {
return false
}
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
return rv.Len() > 0
},
clear: func(p pointer) {
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
rv.Set(reflect.Zero(rv.Type()))
},
get: func(p pointer) pref.Value {
if p.IsNil() {
return conv.Zero()
}
rv := p.Apply(fieldOffset).AsValueOf(fs.Type)
return conv.PBValueOf(rv)
},
set: func(p pointer, v pref.Value) {
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
rv.Set(reflect.ValueOf(v.List().(unwrapper).protoUnwrap()).Elem())
},
mutable: func(p pointer) pref.Value {
v := p.Apply(fieldOffset).AsValueOf(fs.Type)
return conv.PBValueOf(v)
},
newField: func() pref.Value {
return conv.New()
},
}
}
var (
nilBytes = reflect.ValueOf([]byte(nil))
emptyBytes = reflect.ValueOf([]byte{})
)
func fieldInfoForScalar(fd pref.FieldDescriptor, fs reflect.StructField, x exporter) fieldInfo {
ft := fs.Type
nullable := fd.Syntax() == pref.Proto2
isBytes := ft.Kind() == reflect.Slice && ft.Elem().Kind() == reflect.Uint8
if nullable {
if ft.Kind() != reflect.Ptr && ft.Kind() != reflect.Slice {
panic(fmt.Sprintf("invalid type: got %v, want pointer", ft))
}
if ft.Kind() == reflect.Ptr {
ft = ft.Elem()
}
}
conv := NewConverter(ft, fd)
// TODO: Implement unsafe fast path?
fieldOffset := offsetOf(fs, x)
return fieldInfo{
fieldDesc: fd,
has: func(p pointer) bool {
if p.IsNil() {
return false
}
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if nullable {
return !rv.IsNil()
}
switch rv.Kind() {
case reflect.Bool:
return rv.Bool()
case reflect.Int32, reflect.Int64:
return rv.Int() != 0
case reflect.Uint32, reflect.Uint64:
return rv.Uint() != 0
case reflect.Float32, reflect.Float64:
return rv.Float() != 0 || math.Signbit(rv.Float())
case reflect.String, reflect.Slice:
return rv.Len() > 0
default:
panic(fmt.Sprintf("invalid type: %v", rv.Type())) // should never happen
}
},
clear: func(p pointer) {
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
rv.Set(reflect.Zero(rv.Type()))
},
get: func(p pointer) pref.Value {
if p.IsNil() {
return conv.Zero()
}
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if nullable {
if rv.IsNil() {
return conv.Zero()
}
if rv.Kind() == reflect.Ptr {
rv = rv.Elem()
}
}
return conv.PBValueOf(rv)
},
set: func(p pointer, v pref.Value) {
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if nullable && rv.Kind() == reflect.Ptr {
if rv.IsNil() {
rv.Set(reflect.New(ft))
}
rv = rv.Elem()
}
rv.Set(conv.GoValueOf(v))
if isBytes && rv.Len() == 0 {
if nullable {
rv.Set(emptyBytes) // preserve presence in proto2
} else {
rv.Set(nilBytes) // do not preserve presence in proto3
}
}
},
newField: func() pref.Value {
return conv.New()
},
}
}
func fieldInfoForWeakMessage(fd pref.FieldDescriptor, weakOffset offset) fieldInfo {
if !flags.ProtoLegacy {
panic("no support for proto1 weak fields")
}
var once sync.Once
var messageType pref.MessageType
lazyInit := func() {
once.Do(func() {
messageName := fd.Message().FullName()
messageType, _ = preg.GlobalTypes.FindMessageByName(messageName)
if messageType == nil {
panic(fmt.Sprintf("weak message %v is not linked in", messageName))
}
})
}
num := int32(fd.Number())
return fieldInfo{
fieldDesc: fd,
has: func(p pointer) bool {
if p.IsNil() {
return false
}
fs := p.Apply(weakOffset).WeakFields()
_, ok := (*fs)[num]
return ok
},
clear: func(p pointer) {
fs := p.Apply(weakOffset).WeakFields()
delete(*fs, num)
},
get: func(p pointer) pref.Value {
lazyInit()
if p.IsNil() {
return pref.ValueOf(messageType.Zero())
}
fs := p.Apply(weakOffset).WeakFields()
m, ok := (*fs)[num]
if !ok {
return pref.ValueOf(messageType.Zero())
}
return pref.ValueOf(m.(pref.ProtoMessage).ProtoReflect())
},
set: func(p pointer, v pref.Value) {
lazyInit()
m := v.Message()
if m.Descriptor() != messageType.Descriptor() {
panic("mismatching message descriptor")
}
fs := p.Apply(weakOffset).WeakFields()
if *fs == nil {
*fs = make(WeakFields)
}
(*fs)[num] = m.Interface().(piface.MessageV1)
},
mutable: func(p pointer) pref.Value {
lazyInit()
fs := p.Apply(weakOffset).WeakFields()
if *fs == nil {
*fs = make(WeakFields)
}
m, ok := (*fs)[num]
if !ok {
m = messageType.New().Interface().(piface.MessageV1)
(*fs)[num] = m
}
return pref.ValueOf(m.(pref.ProtoMessage).ProtoReflect())
},
newMessage: func() pref.Message {
lazyInit()
return messageType.New()
},
newField: func() pref.Value {
lazyInit()
return pref.ValueOf(messageType.New())
},
}
}
func fieldInfoForMessage(fd pref.FieldDescriptor, fs reflect.StructField, x exporter) fieldInfo {
ft := fs.Type
conv := NewConverter(ft, fd)
// TODO: Implement unsafe fast path?
fieldOffset := offsetOf(fs, x)
return fieldInfo{
fieldDesc: fd,
has: func(p pointer) bool {
if p.IsNil() {
return false
}
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
return !rv.IsNil()
},
clear: func(p pointer) {
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
rv.Set(reflect.Zero(rv.Type()))
},
get: func(p pointer) pref.Value {
if p.IsNil() {
return conv.Zero()
}
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
return conv.PBValueOf(rv)
},
set: func(p pointer, v pref.Value) {
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
rv.Set(conv.GoValueOf(v))
if rv.IsNil() {
panic("invalid nil pointer")
}
},
mutable: func(p pointer) pref.Value {
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if rv.IsNil() {
rv.Set(conv.GoValueOf(conv.New()))
}
return conv.PBValueOf(rv)
},
newMessage: func() pref.Message {
return conv.New().Message()
},
newField: func() pref.Value {
return conv.New()
},
}
}
type oneofInfo struct {
oneofDesc pref.OneofDescriptor
which func(pointer) pref.FieldNumber
}
func makeOneofInfo(od pref.OneofDescriptor, fs reflect.StructField, x exporter, wrappersByType map[reflect.Type]pref.FieldNumber) *oneofInfo {
fieldOffset := offsetOf(fs, x)
return &oneofInfo{
oneofDesc: od,
which: func(p pointer) pref.FieldNumber {
if p.IsNil() {
return 0
}
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if rv.IsNil() {
return 0
}
return wrappersByType[rv.Elem().Type().Elem()]
},
}
}