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// 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 prototype
import (
"bytes"
"fmt"
"strings"
"sync"
pragma "github.com/golang/protobuf/v2/internal/pragma"
pfmt "github.com/golang/protobuf/v2/internal/typefmt"
pref "github.com/golang/protobuf/v2/reflect/protoreflect"
)
// inheritedMeta is information inherited from the parent.
type inheritedMeta struct {
parent pref.Descriptor
index int
syntax pref.Syntax
fullName pref.FullName
}
func (m *inheritedMeta) init(nb *nameBuilder, parent pref.Descriptor, index int, name pref.Name, child bool) {
// Most descriptors are namespaced as a child of their parent.
// However, EnumValues are the exception in that they are namespaced
// as a sibling of the parent Enum type.
prefix := parent.FullName()
if child {
prefix = prefix.Parent()
}
m.parent = parent
m.index = index
m.syntax = parent.Syntax()
m.fullName = nb.Append(prefix, name)
}
type fileMeta struct {
ms messagesMeta
es enumsMeta
xs extensionsMeta
ss servicesMeta
ds descriptorsMeta
}
type fileDesc struct{ f *File }
func newFile(f *File) fileDesc {
if f.fileMeta != nil {
panic("already initialized")
}
f.fileMeta = new(fileMeta)
return fileDesc{f}
}
func (t fileDesc) Parent() (pref.Descriptor, bool) { return nil, false }
func (t fileDesc) Index() int { return 0 }
func (t fileDesc) Syntax() pref.Syntax { return t.f.Syntax }
func (t fileDesc) Name() pref.Name { return t.f.Package.Name() }
func (t fileDesc) FullName() pref.FullName { return t.f.Package }
func (t fileDesc) IsPlaceholder() bool { return false }
func (t fileDesc) DescriptorProto() (pref.Message, bool) { return nil, false }
func (t fileDesc) Options() pref.ProtoMessage { return t.f.Options }
func (t fileDesc) Path() string { return t.f.Path }
func (t fileDesc) Package() pref.FullName { return t.f.Package }
func (t fileDesc) Imports() pref.FileImports { return (*fileImports)(&t.f.Imports) }
func (t fileDesc) Messages() pref.MessageDescriptors { return t.f.ms.lazyInit(t, t.f.Messages) }
func (t fileDesc) Enums() pref.EnumDescriptors { return t.f.es.lazyInit(t, t.f.Enums) }
func (t fileDesc) Extensions() pref.ExtensionDescriptors { return t.f.xs.lazyInit(t, t.f.Extensions) }
func (t fileDesc) Services() pref.ServiceDescriptors { return t.f.ss.lazyInit(t, t.f.Services) }
func (t fileDesc) DescriptorByName(s pref.FullName) pref.Descriptor { return t.f.ds.lookup(t, s) }
func (t fileDesc) Format(s fmt.State, r rune) { pfmt.FormatDesc(s, r, t) }
func (t fileDesc) ProtoType(pref.FileDescriptor) {}
func (t fileDesc) ProtoInternal(pragma.DoNotImplement) {}
// descriptorsMeta is a lazily initialized map of all descriptors declared in
// the file by full name.
type descriptorsMeta struct {
once sync.Once
m map[pref.FullName]pref.Descriptor
}
func (m *descriptorsMeta) lookup(fd pref.FileDescriptor, s pref.FullName) pref.Descriptor {
m.once.Do(func() {
m.m = make(map[pref.FullName]pref.Descriptor)
m.initMap(fd)
delete(m.m, fd.Package()) // avoid registering the file descriptor itself
})
return m.m[s]
}
func (m *descriptorsMeta) initMap(d pref.Descriptor) {
m.m[d.FullName()] = d
if ds, ok := d.(interface {
Enums() pref.EnumDescriptors
}); ok {
for i := 0; i < ds.Enums().Len(); i++ {
m.initMap(ds.Enums().Get(i))
}
}
if ds, ok := d.(interface {
Values() pref.EnumValueDescriptors
}); ok {
for i := 0; i < ds.Values().Len(); i++ {
m.initMap(ds.Values().Get(i))
}
}
if ds, ok := d.(interface {
Messages() pref.MessageDescriptors
}); ok {
for i := 0; i < ds.Messages().Len(); i++ {
m.initMap(ds.Messages().Get(i))
}
}
if ds, ok := d.(interface {
Fields() pref.FieldDescriptors
}); ok {
for i := 0; i < ds.Fields().Len(); i++ {
m.initMap(ds.Fields().Get(i))
}
}
if ds, ok := d.(interface {
Oneofs() pref.OneofDescriptors
}); ok {
for i := 0; i < ds.Oneofs().Len(); i++ {
m.initMap(ds.Oneofs().Get(i))
}
}
if ds, ok := d.(interface {
Extensions() pref.ExtensionDescriptors
}); ok {
for i := 0; i < ds.Extensions().Len(); i++ {
m.initMap(ds.Extensions().Get(i))
}
}
if ds, ok := d.(interface {
Services() pref.ServiceDescriptors
}); ok {
for i := 0; i < ds.Services().Len(); i++ {
m.initMap(ds.Services().Get(i))
}
}
if ds, ok := d.(interface {
Methods() pref.MethodDescriptors
}); ok {
for i := 0; i < ds.Methods().Len(); i++ {
m.initMap(ds.Methods().Get(i))
}
}
}
type messageMeta struct {
inheritedMeta
fs fieldsMeta
os oneofsMeta
ns numbersMeta
ms messagesMeta
es enumsMeta
xs extensionsMeta
mo messageOptions
}
type messageDesc struct{ m *Message }
func (t messageDesc) Parent() (pref.Descriptor, bool) { return t.m.parent, true }
func (t messageDesc) Index() int { return t.m.index }
func (t messageDesc) Syntax() pref.Syntax { return t.m.syntax }
func (t messageDesc) Name() pref.Name { return t.m.Name }
func (t messageDesc) FullName() pref.FullName { return t.m.fullName }
func (t messageDesc) IsPlaceholder() bool { return false }
func (t messageDesc) DescriptorProto() (pref.Message, bool) { return nil, false }
func (t messageDesc) Options() pref.ProtoMessage { return t.m.Options }
func (t messageDesc) IsMapEntry() bool { return t.m.mo.lazyInit(t).isMapEntry }
func (t messageDesc) Fields() pref.FieldDescriptors { return t.m.fs.lazyInit(t, t.m.Fields) }
func (t messageDesc) Oneofs() pref.OneofDescriptors { return t.m.os.lazyInit(t, t.m.Oneofs) }
func (t messageDesc) RequiredNumbers() pref.FieldNumbers { return t.m.ns.lazyInit(t.m.Fields) }
func (t messageDesc) ExtensionRanges() pref.FieldRanges { return (*ranges)(&t.m.ExtensionRanges) }
func (t messageDesc) Messages() pref.MessageDescriptors { return t.m.ms.lazyInit(t, t.m.Messages) }
func (t messageDesc) Enums() pref.EnumDescriptors { return t.m.es.lazyInit(t, t.m.Enums) }
func (t messageDesc) Extensions() pref.ExtensionDescriptors { return t.m.xs.lazyInit(t, t.m.Extensions) }
func (t messageDesc) Format(s fmt.State, r rune) { pfmt.FormatDesc(s, r, t) }
func (t messageDesc) ProtoType(pref.MessageDescriptor) {}
func (t messageDesc) ProtoInternal(pragma.DoNotImplement) {}
type messageOptions struct {
once sync.Once
isMapEntry bool
}
func (p *messageOptions) lazyInit(m pref.MessageDescriptor) *messageOptions {
p.once.Do(func() {
if m.Options() != nil {
const mapEntryFieldNumber = 7 // google.protobuf.MessageOptions.map_entry
fs := m.Options().ProtoReflect().KnownFields()
p.isMapEntry = fs.Get(mapEntryFieldNumber).Bool()
}
})
return p
}
type fieldMeta struct {
inheritedMeta
js jsonName
dv defaultValue
ot oneofReference
mt messageReference
et enumReference
fo fieldOptions
}
type fieldDesc struct{ f *Field }
func (t fieldDesc) Parent() (pref.Descriptor, bool) { return t.f.parent, true }
func (t fieldDesc) Index() int { return t.f.index }
func (t fieldDesc) Syntax() pref.Syntax { return t.f.syntax }
func (t fieldDesc) Name() pref.Name { return t.f.Name }
func (t fieldDesc) FullName() pref.FullName { return t.f.fullName }
func (t fieldDesc) IsPlaceholder() bool { return false }
func (t fieldDesc) DescriptorProto() (pref.Message, bool) { return nil, false }
func (t fieldDesc) Options() pref.ProtoMessage { return t.f.Options }
func (t fieldDesc) Number() pref.FieldNumber { return t.f.Number }
func (t fieldDesc) Cardinality() pref.Cardinality { return t.f.Cardinality }
func (t fieldDesc) Kind() pref.Kind { return t.f.Kind }
func (t fieldDesc) JSONName() string { return t.f.js.lazyInit(t.f) }
func (t fieldDesc) IsPacked() bool { return t.f.fo.lazyInit(t).isPacked }
func (t fieldDesc) IsWeak() bool { return t.f.fo.lazyInit(t).isWeak }
func (t fieldDesc) IsMap() bool { return t.f.fo.lazyInit(t).isMap }
func (t fieldDesc) Default() pref.Value { return t.f.dv.value(t, t.f.Default) }
func (t fieldDesc) DefaultEnumValue() pref.EnumValueDescriptor { return t.f.dv.enum(t, t.f.Default) }
func (t fieldDesc) HasDefault() bool { return t.f.Default.IsValid() }
func (t fieldDesc) OneofType() pref.OneofDescriptor { return t.f.ot.lazyInit(t, t.f.OneofName) }
func (t fieldDesc) ExtendedType() pref.MessageDescriptor { return nil }
func (t fieldDesc) MessageType() pref.MessageDescriptor { return t.f.mt.lazyInit(t, &t.f.MessageType) }
func (t fieldDesc) EnumType() pref.EnumDescriptor { return t.f.et.lazyInit(t, &t.f.EnumType) }
func (t fieldDesc) Format(s fmt.State, r rune) { pfmt.FormatDesc(s, r, t) }
func (t fieldDesc) ProtoType(pref.FieldDescriptor) {}
func (t fieldDesc) ProtoInternal(pragma.DoNotImplement) {}
type jsonName struct{ once sync.Once }
func (p *jsonName) lazyInit(f *Field) string {
p.once.Do(func() {
// TODO: We may need to share this logic with jsonpb for implementation
// of the FieldMask well-known type.
if f.JSONName != "" {
return
}
var b []byte
var wasUnderscore bool
for i := 0; i < len(f.Name); i++ { // proto identifiers are always ASCII
c := f.Name[i]
if c != '_' {
isLower := 'a' <= c && c <= 'z'
if wasUnderscore && isLower {
c -= 'a' - 'A'
}
b = append(b, c)
}
wasUnderscore = c == '_'
}
f.JSONName = string(b)
})
return f.JSONName
}
// oneofReference resolves the name of a oneof by searching the parent
// message for the matching OneofDescriptor declaration.
type oneofReference struct {
once sync.Once
otyp pref.OneofDescriptor
}
func (p *oneofReference) lazyInit(parent pref.Descriptor, name pref.Name) pref.OneofDescriptor {
p.once.Do(func() {
if name != "" {
mtyp, _ := parent.Parent()
p.otyp = mtyp.(pref.MessageDescriptor).Oneofs().ByName(name)
// TODO: We need validate to detect this mismatch.
}
})
return p.otyp
}
type fieldOptions struct {
once sync.Once
isPacked bool
isWeak bool
isMap bool
}
func (p *fieldOptions) lazyInit(f pref.FieldDescriptor) *fieldOptions {
p.once.Do(func() {
if f.Cardinality() == pref.Repeated {
// In proto3, repeated fields of scalar numeric types use
// packed encoding by default.
// See https://developers.google.com/protocol-buffers/docs/proto3
if f.Syntax() == pref.Proto3 {
p.isPacked = isScalarNumeric[f.Kind()]
}
if f.Kind() == pref.MessageKind {
p.isMap = f.MessageType().IsMapEntry()
}
}
if f.Options() != nil {
const packedFieldNumber = 2 // google.protobuf.FieldOptions.packed
const weakFieldNumber = 10 // google.protobuf.FieldOptions.weak
fs := f.Options().ProtoReflect().KnownFields()
if fs.Has(packedFieldNumber) {
p.isPacked = fs.Get(packedFieldNumber).Bool()
}
p.isWeak = fs.Get(weakFieldNumber).Bool()
}
})
return p
}
// isPacked reports whether the packed options is set.
func isPacked(m pref.ProtoMessage) (isPacked bool) {
if m != nil {
const packedFieldNumber = 2 // google.protobuf.FieldOptions.packed
fs := m.ProtoReflect().KnownFields()
isPacked = fs.Get(packedFieldNumber).Bool()
}
return isPacked
}
// isWeak reports whether the weak options is set.
func isWeak(m pref.ProtoMessage) (isWeak bool) {
if m != nil {
const weakFieldNumber = 10 // google.protobuf.FieldOptions.weak
fs := m.ProtoReflect().KnownFields()
isWeak = fs.Get(weakFieldNumber).Bool()
}
return isWeak
}
var isScalarNumeric = map[pref.Kind]bool{
pref.BoolKind: true,
pref.EnumKind: true,
pref.Int32Kind: true,
pref.Sint32Kind: true,
pref.Uint32Kind: true,
pref.Int64Kind: true,
pref.Sint64Kind: true,
pref.Uint64Kind: true,
pref.Sfixed32Kind: true,
pref.Fixed32Kind: true,
pref.FloatKind: true,
pref.Sfixed64Kind: true,
pref.Fixed64Kind: true,
pref.DoubleKind: true,
}
type oneofMeta struct {
inheritedMeta
fs oneofFieldsMeta
}
type oneofDesc struct{ o *Oneof }
func (t oneofDesc) Parent() (pref.Descriptor, bool) { return t.o.parent, true }
func (t oneofDesc) Index() int { return t.o.index }
func (t oneofDesc) Syntax() pref.Syntax { return t.o.syntax }
func (t oneofDesc) Name() pref.Name { return t.o.Name }
func (t oneofDesc) FullName() pref.FullName { return t.o.fullName }
func (t oneofDesc) IsPlaceholder() bool { return false }
func (t oneofDesc) DescriptorProto() (pref.Message, bool) { return nil, false }
func (t oneofDesc) Options() pref.ProtoMessage { return t.o.Options }
func (t oneofDesc) Fields() pref.FieldDescriptors { return t.o.fs.lazyInit(t) }
func (t oneofDesc) Format(s fmt.State, r rune) { pfmt.FormatDesc(s, r, t) }
func (t oneofDesc) ProtoType(pref.OneofDescriptor) {}
func (t oneofDesc) ProtoInternal(pragma.DoNotImplement) {}
type extensionMeta struct {
inheritedMeta
dv defaultValue
xt messageReference
mt messageReference
et enumReference
}
type extensionDesc struct{ x *Extension }
func (t extensionDesc) Parent() (pref.Descriptor, bool) { return t.x.parent, true }
func (t extensionDesc) Syntax() pref.Syntax { return t.x.syntax }
func (t extensionDesc) Index() int { return t.x.index }
func (t extensionDesc) Name() pref.Name { return t.x.Name }
func (t extensionDesc) FullName() pref.FullName { return t.x.fullName }
func (t extensionDesc) IsPlaceholder() bool { return false }
func (t extensionDesc) DescriptorProto() (pref.Message, bool) { return nil, false }
func (t extensionDesc) Options() pref.ProtoMessage { return t.x.Options }
func (t extensionDesc) Number() pref.FieldNumber { return t.x.Number }
func (t extensionDesc) Cardinality() pref.Cardinality { return t.x.Cardinality }
func (t extensionDesc) Kind() pref.Kind { return t.x.Kind }
func (t extensionDesc) JSONName() string { return "" }
func (t extensionDesc) IsPacked() bool { return isPacked(t.Options()) }
func (t extensionDesc) IsWeak() bool { return false }
func (t extensionDesc) IsMap() bool { return false }
func (t extensionDesc) Default() pref.Value { return t.x.dv.value(t, t.x.Default) }
func (t extensionDesc) DefaultEnumValue() pref.EnumValueDescriptor { return t.x.dv.enum(t, t.x.Default) }
func (t extensionDesc) HasDefault() bool { return t.x.Default.IsValid() }
func (t extensionDesc) OneofType() pref.OneofDescriptor { return nil }
func (t extensionDesc) ExtendedType() pref.MessageDescriptor {
return t.x.xt.lazyInit(t, &t.x.ExtendedType)
}
func (t extensionDesc) MessageType() pref.MessageDescriptor {
return t.x.mt.lazyInit(t, &t.x.MessageType)
}
func (t extensionDesc) EnumType() pref.EnumDescriptor { return t.x.et.lazyInit(t, &t.x.EnumType) }
func (t extensionDesc) Format(s fmt.State, r rune) { pfmt.FormatDesc(s, r, t) }
func (t extensionDesc) ProtoType(pref.FieldDescriptor) {}
func (t extensionDesc) ProtoInternal(pragma.DoNotImplement) {}
type enumMeta struct {
inheritedMeta
vs enumValuesMeta
}
type enumDesc struct{ e *Enum }
func (t enumDesc) Parent() (pref.Descriptor, bool) { return t.e.parent, true }
func (t enumDesc) Index() int { return t.e.index }
func (t enumDesc) Syntax() pref.Syntax { return t.e.syntax }
func (t enumDesc) Name() pref.Name { return t.e.Name }
func (t enumDesc) FullName() pref.FullName { return t.e.fullName }
func (t enumDesc) IsPlaceholder() bool { return false }
func (t enumDesc) DescriptorProto() (pref.Message, bool) { return nil, false }
func (t enumDesc) Options() pref.ProtoMessage { return t.e.Options }
func (t enumDesc) Values() pref.EnumValueDescriptors { return t.e.vs.lazyInit(t, t.e.Values) }
func (t enumDesc) Format(s fmt.State, r rune) { pfmt.FormatDesc(s, r, t) }
func (t enumDesc) ProtoType(pref.EnumDescriptor) {}
func (t enumDesc) ProtoInternal(pragma.DoNotImplement) {}
type enumValueMeta struct {
inheritedMeta
}
type enumValueDesc struct{ v *EnumValue }
func (t enumValueDesc) Parent() (pref.Descriptor, bool) { return t.v.parent, true }
func (t enumValueDesc) Index() int { return t.v.index }
func (t enumValueDesc) Syntax() pref.Syntax { return t.v.syntax }
func (t enumValueDesc) Name() pref.Name { return t.v.Name }
func (t enumValueDesc) FullName() pref.FullName { return t.v.fullName }
func (t enumValueDesc) IsPlaceholder() bool { return false }
func (t enumValueDesc) DescriptorProto() (pref.Message, bool) { return nil, false }
func (t enumValueDesc) Options() pref.ProtoMessage { return t.v.Options }
func (t enumValueDesc) Number() pref.EnumNumber { return t.v.Number }
func (t enumValueDesc) Format(s fmt.State, r rune) { pfmt.FormatDesc(s, r, t) }
func (t enumValueDesc) ProtoType(pref.EnumValueDescriptor) {}
func (t enumValueDesc) ProtoInternal(pragma.DoNotImplement) {}
type serviceMeta struct {
inheritedMeta
ms methodsMeta
}
type serviceDesc struct{ s *Service }
func (t serviceDesc) Parent() (pref.Descriptor, bool) { return t.s.parent, true }
func (t serviceDesc) Index() int { return t.s.index }
func (t serviceDesc) Syntax() pref.Syntax { return t.s.syntax }
func (t serviceDesc) Name() pref.Name { return t.s.Name }
func (t serviceDesc) FullName() pref.FullName { return t.s.fullName }
func (t serviceDesc) IsPlaceholder() bool { return false }
func (t serviceDesc) DescriptorProto() (pref.Message, bool) { return nil, false }
func (t serviceDesc) Options() pref.ProtoMessage { return t.s.Options }
func (t serviceDesc) Methods() pref.MethodDescriptors { return t.s.ms.lazyInit(t, t.s.Methods) }
func (t serviceDesc) Format(s fmt.State, r rune) { pfmt.FormatDesc(s, r, t) }
func (t serviceDesc) ProtoType(pref.ServiceDescriptor) {}
func (t serviceDesc) ProtoInternal(pragma.DoNotImplement) {}
type methodMeta struct {
inheritedMeta
mit messageReference
mot messageReference
}
type methodDesc struct{ m *Method }
func (t methodDesc) Parent() (pref.Descriptor, bool) { return t.m.parent, true }
func (t methodDesc) Index() int { return t.m.index }
func (t methodDesc) Syntax() pref.Syntax { return t.m.syntax }
func (t methodDesc) Name() pref.Name { return t.m.Name }
func (t methodDesc) FullName() pref.FullName { return t.m.fullName }
func (t methodDesc) IsPlaceholder() bool { return false }
func (t methodDesc) DescriptorProto() (pref.Message, bool) { return nil, false }
func (t methodDesc) Options() pref.ProtoMessage { return t.m.Options }
func (t methodDesc) InputType() pref.MessageDescriptor { return t.m.mit.lazyInit(t, &t.m.InputType) }
func (t methodDesc) OutputType() pref.MessageDescriptor { return t.m.mot.lazyInit(t, &t.m.OutputType) }
func (t methodDesc) IsStreamingClient() bool { return t.m.IsStreamingClient }
func (t methodDesc) IsStreamingServer() bool { return t.m.IsStreamingServer }
func (t methodDesc) Format(s fmt.State, r rune) { pfmt.FormatDesc(s, r, t) }
func (t methodDesc) ProtoType(pref.MethodDescriptor) {}
func (t methodDesc) ProtoInternal(pragma.DoNotImplement) {}
type defaultValue struct {
once sync.Once
val pref.Value
eval pref.EnumValueDescriptor
buf []byte
}
var (
zeroBool = pref.ValueOf(false)
zeroInt32 = pref.ValueOf(int32(0))
zeroInt64 = pref.ValueOf(int64(0))
zeroUint32 = pref.ValueOf(uint32(0))
zeroUint64 = pref.ValueOf(uint64(0))
zeroFloat32 = pref.ValueOf(float32(0))
zeroFloat64 = pref.ValueOf(float64(0))
zeroString = pref.ValueOf(string(""))
zeroBytes = pref.ValueOf([]byte(nil))
zeroEnum = pref.ValueOf(pref.EnumNumber(0))
)
func (p *defaultValue) lazyInit(t pref.FieldDescriptor, v pref.Value) {
p.once.Do(func() {
p.val = v
if v.IsValid() {
switch t.Kind() {
case pref.EnumKind:
// Treat a string value as an identifier referencing some enum
// value by name and extract the enum number.
// If this fails, validateMessage will later detect that the
// default value for an enum value is the wrong type.
switch v := v.Interface().(type) {
case string:
if ev := t.EnumType().Values().ByName(pref.Name(v)); ev != nil {
p.eval = ev
p.val = pref.ValueOf(p.eval.Number())
}
case pref.EnumNumber:
p.eval = t.EnumType().Values().ByNumber(v)
}
case pref.BytesKind:
// Store a copy of the default bytes, so that we can detect
// accidental mutations of the original value.
if b, ok := v.Interface().([]byte); ok && len(b) > 0 {
p.buf = append([]byte(nil), b...)
}
}
return
}
switch t.Kind() {
case pref.BoolKind:
p.val = zeroBool
case pref.Int32Kind, pref.Sint32Kind, pref.Sfixed32Kind:
p.val = zeroInt32
case pref.Int64Kind, pref.Sint64Kind, pref.Sfixed64Kind:
p.val = zeroInt64
case pref.Uint32Kind, pref.Fixed32Kind:
p.val = zeroUint32
case pref.Uint64Kind, pref.Fixed64Kind:
p.val = zeroUint64
case pref.FloatKind:
p.val = zeroFloat32
case pref.DoubleKind:
p.val = zeroFloat64
case pref.StringKind:
p.val = zeroString
case pref.BytesKind:
p.val = zeroBytes
case pref.EnumKind:
p.val = zeroEnum
if t.Syntax() == pref.Proto2 {
if et := t.EnumType(); et != nil {
if vs := et.Values(); vs.Len() > 0 {
p.val = pref.ValueOf(vs.Get(0).Number())
}
}
}
}
})
if len(p.buf) > 0 && !bytes.Equal(p.buf, p.val.Bytes()) {
// TODO: Avoid panic if we're running with the race detector and instead
// spawn a goroutine that periodically resets this value back to the
// original to induce a race that can be detected by the detector.
panic(fmt.Sprintf("proto: detected mutation on the default bytes for %v", t.FullName()))
}
}
func (p *defaultValue) value(t pref.FieldDescriptor, v pref.Value) pref.Value {
p.lazyInit(t, v)
return p.val
}
func (p *defaultValue) enum(t pref.FieldDescriptor, v pref.Value) pref.EnumValueDescriptor {
p.lazyInit(t, v)
return p.eval
}
// messageReference resolves PlaceholderMessages that reference declarations
// within the FileDescriptor tree that parent is a member of.
type messageReference struct{ once sync.Once }
func (p *messageReference) lazyInit(parent pref.Descriptor, pt *pref.MessageDescriptor) pref.MessageDescriptor {
p.once.Do(func() {
if t := *pt; t != nil && t.IsPlaceholder() {
if d, ok := resolveReference(parent, t.FullName()).(pref.MessageDescriptor); ok {
*pt = d
}
}
})
return *pt
}
// enumReference resolves PlaceholderEnums that reference declarations
// within the FileDescriptor tree that parent is a member of.
type enumReference struct{ once sync.Once }
func (p *enumReference) lazyInit(parent pref.Descriptor, pt *pref.EnumDescriptor) pref.EnumDescriptor {
p.once.Do(func() {
if t := *pt; t != nil && t.IsPlaceholder() {
if d, ok := resolveReference(parent, t.FullName()).(pref.EnumDescriptor); ok {
*pt = d
}
}
})
return *pt
}
// resolveReference searches parent for the MessageDescriptor or EnumDescriptor
// declaration identified by refName. This returns nil if not found.
func resolveReference(parent pref.Descriptor, refName pref.FullName) pref.Descriptor {
// Ascend upwards until a prefix match is found.
cur := parent
for cur != nil {
curName := cur.FullName()
if strings.HasPrefix(string(refName), string(curName)) {
if len(refName) == len(curName) {
refName = refName[len(curName):]
break // e.g., refName: foo.firetruck, curName: foo.firetruck
} else if refName[len(curName)] == '.' {
refName = refName[len(curName)+len("."):]
break // e.g., refName: foo.firetruck.driver, curName: foo.firetruck
} else if len(curName) == 0 {
break // FileDescriptor has no package name
}
// No match. (e.g., refName: foo.firetruck, curName: foo.fire)
}
cur, _ = cur.Parent() // nil after ascending above FileDescriptor
}
// Descend downwards to resolve all relative names.
for cur != nil && len(refName) > 0 {
var head pref.Name
head, refName = pref.Name(refName), ""
if i := strings.IndexByte(string(head), '.'); i >= 0 {
head, refName = head[:i], pref.FullName(head[i+len("."):])
}
// Search the current descriptor for the nested declaration.
var next pref.Descriptor
if t, ok := cur.(interface {
Messages() pref.MessageDescriptors
}); ok && next == nil {
if d := t.Messages().ByName(head); d != nil {
next = d
}
}
if t, ok := cur.(interface {
Enums() pref.EnumDescriptors
}); ok && next == nil {
if d := t.Enums().ByName(head); d != nil {
next = d
}
}
cur = next // nil if not found
}
return cur
}