// 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"
"google.golang.org/protobuf/reflect/protoreflect"
"google.golang.org/protobuf/reflect/protoregistry"
)
type fieldInfo struct {
fieldDesc protoreflect.FieldDescriptor
// These fields are used for protobuf reflection support.
has func(pointer) bool
clear func(pointer)
get func(pointer) protoreflect.Value
set func(pointer, protoreflect.Value)
mutable func(pointer) protoreflect.Value
newMessage func() protoreflect.Message
newField func() protoreflect.Value
}
func fieldInfoForMissing(fd protoreflect.FieldDescriptor) fieldInfo {
// This never occurs for generated message types.
// It implies that a hand-crafted type has missing Go fields
// for specific protobuf message fields.
return fieldInfo{
fieldDesc: fd,
has: func(p pointer) bool {
return false
},
clear: func(p pointer) {
panic("missing Go struct field for " + string(fd.FullName()))
},
get: func(p pointer) protoreflect.Value {
return fd.Default()
},
set: func(p pointer, v protoreflect.Value) {
panic("missing Go struct field for " + string(fd.FullName()))
},
mutable: func(p pointer) protoreflect.Value {
panic("missing Go struct field for " + string(fd.FullName()))
},
newMessage: func() protoreflect.Message {
panic("missing Go struct field for " + string(fd.FullName()))
},
newField: func() protoreflect.Value {
if v := fd.Default(); v.IsValid() {
return v
}
panic("missing Go struct field for " + string(fd.FullName()))
},
}
}
func fieldInfoForOneof(fd protoreflect.FieldDescriptor, fs reflect.StructField, x exporter, ot reflect.Type) fieldInfo {
ft := fs.Type
if ft.Kind() != reflect.Interface {
panic(fmt.Sprintf("field %v has invalid type: got %v, want interface kind", fd.FullName(), ft))
}
if ot.Kind() != reflect.Struct {
panic(fmt.Sprintf("field %v has invalid type: got %v, want struct kind", fd.FullName(), ot))
}
if !reflect.PtrTo(ot).Implements(ft) {
panic(fmt.Sprintf("field %v has invalid type: %v does not implement %v", fd.FullName(), 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) protoreflect.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 protoreflect.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) protoreflect.Value {
if !isMessage {
panic(fmt.Sprintf("field %v with invalid Mutable call on field with non-composite type", fd.FullName()))
}
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.Kind() == reflect.Ptr && rv.IsNil() {
rv.Set(conv.GoValueOf(protoreflect.ValueOfMessage(conv.New().Message())))
}
return conv.PBValueOf(rv)
},
newMessage: func() protoreflect.Message {
return conv.New().Message()
},
newField: func() protoreflect.Value {
return conv.New()
},
}
}
func fieldInfoForMap(fd protoreflect.FieldDescriptor, fs reflect.StructField, x exporter) fieldInfo {
ft := fs.Type
if ft.Kind() != reflect.Map {
panic(fmt.Sprintf("field %v has invalid type: got %v, want map kind", fd.FullName(), 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) protoreflect.Value {
if p.IsNil() {
return conv.Zero()
}
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if rv.Len() == 0 {
return conv.Zero()
}
return conv.PBValueOf(rv)
},
set: func(p pointer, v protoreflect.Value) {
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
pv := conv.GoValueOf(v)
if pv.IsNil() {
panic(fmt.Sprintf("map field %v cannot be set with read-only value", fd.FullName()))
}
rv.Set(pv)
},
mutable: func(p pointer) protoreflect.Value {
v := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if v.IsNil() {
v.Set(reflect.MakeMap(fs.Type))
}
return conv.PBValueOf(v)
},
newField: func() protoreflect.Value {
return conv.New()
},
}
}
func fieldInfoForList(fd protoreflect.FieldDescriptor, fs reflect.StructField, x exporter) fieldInfo {
ft := fs.Type
if ft.Kind() != reflect.Slice {
panic(fmt.Sprintf("field %v has invalid type: got %v, want slice kind", fd.FullName(), 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) protoreflect.Value {
if p.IsNil() {
return conv.Zero()
}
rv := p.Apply(fieldOffset).AsValueOf(fs.Type)
if rv.Elem().Len() == 0 {
return conv.Zero()
}
return conv.PBValueOf(rv)
},
set: func(p pointer, v protoreflect.Value) {
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
pv := conv.GoValueOf(v)
if pv.IsNil() {
panic(fmt.Sprintf("list field %v cannot be set with read-only value", fd.FullName()))
}
rv.Set(pv.Elem())
},
mutable: func(p pointer) protoreflect.Value {
v := p.Apply(fieldOffset).AsValueOf(fs.Type)
return conv.PBValueOf(v)
},
newField: func() protoreflect.Value {
return conv.New()
},
}
}
var (
nilBytes = reflect.ValueOf([]byte(nil))
emptyBytes = reflect.ValueOf([]byte{})
)
func fieldInfoForScalar(fd protoreflect.FieldDescriptor, fs reflect.StructField, x exporter) fieldInfo {
ft := fs.Type
nullable := fd.HasPresence()
isBytes := ft.Kind() == reflect.Slice && ft.Elem().Kind() == reflect.Uint8
if nullable {
if ft.Kind() != reflect.Ptr && ft.Kind() != reflect.Slice {
// This never occurs for generated message types.
// Despite the protobuf type system specifying presence,
// the Go field type cannot represent it.
nullable = false
}
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("field %v has invalid type: %v", fd.FullName(), 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) protoreflect.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 protoreflect.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
} else {
rv.Set(nilBytes) // do not preserve presence
}
}
},
newField: func() protoreflect.Value {
return conv.New()
},
}
}
func fieldInfoForWeakMessage(fd protoreflect.FieldDescriptor, weakOffset offset) fieldInfo {
if !flags.ProtoLegacy {
panic("no support for proto1 weak fields")
}
var once sync.Once
var messageType protoreflect.MessageType
lazyInit := func() {
once.Do(func() {
messageName := fd.Message().FullName()
messageType, _ = protoregistry.GlobalTypes.FindMessageByName(messageName)
if messageType == nil {
panic(fmt.Sprintf("weak message %v for field %v is not linked in", messageName, fd.FullName()))
}
})
}
num := fd.Number()
return fieldInfo{
fieldDesc: fd,
has: func(p pointer) bool {
if p.IsNil() {
return false
}
_, ok := p.Apply(weakOffset).WeakFields().get(num)
return ok
},
clear: func(p pointer) {
p.Apply(weakOffset).WeakFields().clear(num)
},
get: func(p pointer) protoreflect.Value {
lazyInit()
if p.IsNil() {
return protoreflect.ValueOfMessage(messageType.Zero())
}
m, ok := p.Apply(weakOffset).WeakFields().get(num)
if !ok {
return protoreflect.ValueOfMessage(messageType.Zero())
}
return protoreflect.ValueOfMessage(m.ProtoReflect())
},
set: func(p pointer, v protoreflect.Value) {
lazyInit()
m := v.Message()
if m.Descriptor() != messageType.Descriptor() {
if got, want := m.Descriptor().FullName(), messageType.Descriptor().FullName(); got != want {
panic(fmt.Sprintf("field %v has mismatching message descriptor: got %v, want %v", fd.FullName(), got, want))
}
panic(fmt.Sprintf("field %v has mismatching message descriptor: %v", fd.FullName(), m.Descriptor().FullName()))
}
p.Apply(weakOffset).WeakFields().set(num, m.Interface())
},
mutable: func(p pointer) protoreflect.Value {
lazyInit()
fs := p.Apply(weakOffset).WeakFields()
m, ok := fs.get(num)
if !ok {
m = messageType.New().Interface()
fs.set(num, m)
}
return protoreflect.ValueOfMessage(m.ProtoReflect())
},
newMessage: func() protoreflect.Message {
lazyInit()
return messageType.New()
},
newField: func() protoreflect.Value {
lazyInit()
return protoreflect.ValueOfMessage(messageType.New())
},
}
}
func fieldInfoForMessage(fd protoreflect.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()
if fs.Type.Kind() != reflect.Ptr {
return !isZero(rv)
}
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) protoreflect.Value {
if p.IsNil() {
return conv.Zero()
}
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
return conv.PBValueOf(rv)
},
set: func(p pointer, v protoreflect.Value) {
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
rv.Set(conv.GoValueOf(v))
if fs.Type.Kind() == reflect.Ptr && rv.IsNil() {
panic(fmt.Sprintf("field %v has invalid nil pointer", fd.FullName()))
}
},
mutable: func(p pointer) protoreflect.Value {
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if fs.Type.Kind() == reflect.Ptr && rv.IsNil() {
rv.Set(conv.GoValueOf(conv.New()))
}
return conv.PBValueOf(rv)
},
newMessage: func() protoreflect.Message {
return conv.New().Message()
},
newField: func() protoreflect.Value {
return conv.New()
},
}
}
type oneofInfo struct {
oneofDesc protoreflect.OneofDescriptor
which func(pointer) protoreflect.FieldNumber
}
func makeOneofInfo(od protoreflect.OneofDescriptor, si structInfo, x exporter) *oneofInfo {
oi := &oneofInfo{oneofDesc: od}
if od.IsSynthetic() {
fs := si.fieldsByNumber[od.Fields().Get(0).Number()]
fieldOffset := offsetOf(fs, x)
oi.which = func(p pointer) protoreflect.FieldNumber {
if p.IsNil() {
return 0
}
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if rv.IsNil() { // valid on either *T or []byte
return 0
}
return od.Fields().Get(0).Number()
}
} else {
fs := si.oneofsByName[od.Name()]
fieldOffset := offsetOf(fs, x)
oi.which = func(p pointer) protoreflect.FieldNumber {
if p.IsNil() {
return 0
}
rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if rv.IsNil() {
return 0
}
rv = rv.Elem()
if rv.IsNil() {
return 0
}
return si.oneofWrappersByType[rv.Type().Elem()]
}
}
return oi
}
// isZero is identical to reflect.Value.IsZero.
// TODO: Remove this when Go1.13 is the minimally supported Go version.
func isZero(v reflect.Value) bool {
switch v.Kind() {
case reflect.Bool:
return !v.Bool()
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return v.Int() == 0
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
return v.Uint() == 0
case reflect.Float32, reflect.Float64:
return math.Float64bits(v.Float()) == 0
case reflect.Complex64, reflect.Complex128:
c := v.Complex()
return math.Float64bits(real(c)) == 0 && math.Float64bits(imag(c)) == 0
case reflect.Array:
for i := 0; i < v.Len(); i++ {
if !isZero(v.Index(i)) {
return false
}
}
return true
case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map, reflect.Ptr, reflect.Slice, reflect.UnsafePointer:
return v.IsNil()
case reflect.String:
return v.Len() == 0
case reflect.Struct:
for i := 0; i < v.NumField(); i++ {
if !isZero(v.Field(i)) {
return false
}
}
return true
default:
panic(&reflect.ValueError{"reflect.Value.IsZero", v.Kind()})
}
}