gtsocial-umbx

message_reflect.go (13923B)

---

 // 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"
 
 	"google.golang.org/protobuf/internal/detrand"
 	"google.golang.org/protobuf/internal/pragma"
 	"google.golang.org/protobuf/reflect/protoreflect"
 )
 
 type reflectMessageInfo struct {
 	fields map[protoreflect.FieldNumber]*fieldInfo
 	oneofs map[protoreflect.Name]*oneofInfo
 
 	// fieldTypes contains the zero value of an enum or message field.
 	// For lists, it contains the element type.
 	// For maps, it contains the entry value type.
 	fieldTypes map[protoreflect.FieldNumber]interface{}
 
 	// denseFields is a subset of fields where:
 	//	0 < fieldDesc.Number() < len(denseFields)
 	// It provides faster access to the fieldInfo, but may be incomplete.
 	denseFields []*fieldInfo
 
 	// rangeInfos is a list of all fields (not belonging to a oneof) and oneofs.
 	rangeInfos []interface{} // either *fieldInfo or *oneofInfo
 
 	getUnknown   func(pointer) protoreflect.RawFields
 	setUnknown   func(pointer, protoreflect.RawFields)
 	extensionMap func(pointer) *extensionMap
 
 	nilMessage atomicNilMessage
 }
 
 // makeReflectFuncs generates the set of functions to support reflection.
 func (mi *MessageInfo) makeReflectFuncs(t reflect.Type, si structInfo) {
 	mi.makeKnownFieldsFunc(si)
 	mi.makeUnknownFieldsFunc(t, si)
 	mi.makeExtensionFieldsFunc(t, si)
 	mi.makeFieldTypes(si)
 }
 
 // makeKnownFieldsFunc generates functions for operations that can be performed
 // on each protobuf message field. It takes in a reflect.Type representing the
 // Go struct and matches message fields with struct fields.
 //
 // This code assumes that the struct is well-formed and panics if there are
 // any discrepancies.
 func (mi *MessageInfo) makeKnownFieldsFunc(si structInfo) {
 	mi.fields = map[protoreflect.FieldNumber]*fieldInfo{}
 	md := mi.Desc
 	fds := md.Fields()
 	for i := 0; i < fds.Len(); i++ {
 		fd := fds.Get(i)
 		fs := si.fieldsByNumber[fd.Number()]
 		isOneof := fd.ContainingOneof() != nil && !fd.ContainingOneof().IsSynthetic()
 		if isOneof {
 			fs = si.oneofsByName[fd.ContainingOneof().Name()]
 		}
 		var fi fieldInfo
 		switch {
 		case fs.Type == nil:
 			fi = fieldInfoForMissing(fd) // never occurs for officially generated message types
 		case isOneof:
 			fi = fieldInfoForOneof(fd, fs, mi.Exporter, si.oneofWrappersByNumber[fd.Number()])
 		case fd.IsMap():
 			fi = fieldInfoForMap(fd, fs, mi.Exporter)
 		case fd.IsList():
 			fi = fieldInfoForList(fd, fs, mi.Exporter)
 		case fd.IsWeak():
 			fi = fieldInfoForWeakMessage(fd, si.weakOffset)
 		case fd.Message() != nil:
 			fi = fieldInfoForMessage(fd, fs, mi.Exporter)
 		default:
 			fi = fieldInfoForScalar(fd, fs, mi.Exporter)
 		}
 		mi.fields[fd.Number()] = &fi
 	}
 
 	mi.oneofs = map[protoreflect.Name]*oneofInfo{}
 	for i := 0; i < md.Oneofs().Len(); i++ {
 		od := md.Oneofs().Get(i)
 		mi.oneofs[od.Name()] = makeOneofInfo(od, si, mi.Exporter)
 	}
 
 	mi.denseFields = make([]*fieldInfo, fds.Len()*2)
 	for i := 0; i < fds.Len(); i++ {
 		if fd := fds.Get(i); int(fd.Number()) < len(mi.denseFields) {
 			mi.denseFields[fd.Number()] = mi.fields[fd.Number()]
 		}
 	}
 
 	for i := 0; i < fds.Len(); {
 		fd := fds.Get(i)
 		if od := fd.ContainingOneof(); od != nil && !od.IsSynthetic() {
 			mi.rangeInfos = append(mi.rangeInfos, mi.oneofs[od.Name()])
 			i += od.Fields().Len()
 		} else {
 			mi.rangeInfos = append(mi.rangeInfos, mi.fields[fd.Number()])
 			i++
 		}
 	}
 
 	// Introduce instability to iteration order, but keep it deterministic.
 	if len(mi.rangeInfos) > 1 && detrand.Bool() {
 		i := detrand.Intn(len(mi.rangeInfos) - 1)
 		mi.rangeInfos[i], mi.rangeInfos[i+1] = mi.rangeInfos[i+1], mi.rangeInfos[i]
 	}
 }
 
 func (mi *MessageInfo) makeUnknownFieldsFunc(t reflect.Type, si structInfo) {
 	switch {
 	case si.unknownOffset.IsValid() && si.unknownType == unknownFieldsAType:
 		// Handle as []byte.
 		mi.getUnknown = func(p pointer) protoreflect.RawFields {
 			if p.IsNil() {
 				return nil
 			}
 			return *p.Apply(mi.unknownOffset).Bytes()
 		}
 		mi.setUnknown = func(p pointer, b protoreflect.RawFields) {
 			if p.IsNil() {
 				panic("invalid SetUnknown on nil Message")
 			}
 			*p.Apply(mi.unknownOffset).Bytes() = b
 		}
 	case si.unknownOffset.IsValid() && si.unknownType == unknownFieldsBType:
 		// Handle as *[]byte.
 		mi.getUnknown = func(p pointer) protoreflect.RawFields {
 			if p.IsNil() {
 				return nil
 			}
 			bp := p.Apply(mi.unknownOffset).BytesPtr()
 			if *bp == nil {
 				return nil
 			}
 			return **bp
 		}
 		mi.setUnknown = func(p pointer, b protoreflect.RawFields) {
 			if p.IsNil() {
 				panic("invalid SetUnknown on nil Message")
 			}
 			bp := p.Apply(mi.unknownOffset).BytesPtr()
 			if *bp == nil {
 				*bp = new([]byte)
 			}
 			**bp = b
 		}
 	default:
 		mi.getUnknown = func(pointer) protoreflect.RawFields {
 			return nil
 		}
 		mi.setUnknown = func(p pointer, _ protoreflect.RawFields) {
 			if p.IsNil() {
 				panic("invalid SetUnknown on nil Message")
 			}
 		}
 	}
 }
 
 func (mi *MessageInfo) makeExtensionFieldsFunc(t reflect.Type, si structInfo) {
 	if si.extensionOffset.IsValid() {
 		mi.extensionMap = func(p pointer) *extensionMap {
 			if p.IsNil() {
 				return (*extensionMap)(nil)
 			}
 			v := p.Apply(si.extensionOffset).AsValueOf(extensionFieldsType)
 			return (*extensionMap)(v.Interface().(*map[int32]ExtensionField))
 		}
 	} else {
 		mi.extensionMap = func(pointer) *extensionMap {
 			return (*extensionMap)(nil)
 		}
 	}
 }
 func (mi *MessageInfo) makeFieldTypes(si structInfo) {
 	md := mi.Desc
 	fds := md.Fields()
 	for i := 0; i < fds.Len(); i++ {
 		var ft reflect.Type
 		fd := fds.Get(i)
 		fs := si.fieldsByNumber[fd.Number()]
 		isOneof := fd.ContainingOneof() != nil && !fd.ContainingOneof().IsSynthetic()
 		if isOneof {
 			fs = si.oneofsByName[fd.ContainingOneof().Name()]
 		}
 		var isMessage bool
 		switch {
 		case fs.Type == nil:
 			continue // never occurs for officially generated message types
 		case isOneof:
 			if fd.Enum() != nil || fd.Message() != nil {
 				ft = si.oneofWrappersByNumber[fd.Number()].Field(0).Type
 			}
 		case fd.IsMap():
 			if fd.MapValue().Enum() != nil || fd.MapValue().Message() != nil {
 				ft = fs.Type.Elem()
 			}
 			isMessage = fd.MapValue().Message() != nil
 		case fd.IsList():
 			if fd.Enum() != nil || fd.Message() != nil {
 				ft = fs.Type.Elem()
 			}
 			isMessage = fd.Message() != nil
 		case fd.Enum() != nil:
 			ft = fs.Type
 			if fd.HasPresence() && ft.Kind() == reflect.Ptr {
 				ft = ft.Elem()
 			}
 		case fd.Message() != nil:
 			ft = fs.Type
 			if fd.IsWeak() {
 				ft = nil
 			}
 			isMessage = true
 		}
 		if isMessage && ft != nil && ft.Kind() != reflect.Ptr {
 			ft = reflect.PtrTo(ft) // never occurs for officially generated message types
 		}
 		if ft != nil {
 			if mi.fieldTypes == nil {
 				mi.fieldTypes = make(map[protoreflect.FieldNumber]interface{})
 			}
 			mi.fieldTypes[fd.Number()] = reflect.Zero(ft).Interface()
 		}
 	}
 }
 
 type extensionMap map[int32]ExtensionField
 
 func (m *extensionMap) Range(f func(protoreflect.FieldDescriptor, protoreflect.Value) bool) {
 	if m != nil {
 		for _, x := range *m {
 			xd := x.Type().TypeDescriptor()
 			v := x.Value()
 			if xd.IsList() && v.List().Len() == 0 {
 				continue
 			}
 			if !f(xd, v) {
 				return
 			}
 		}
 	}
 }
 func (m *extensionMap) Has(xt protoreflect.ExtensionType) (ok bool) {
 	if m == nil {
 		return false
 	}
 	xd := xt.TypeDescriptor()
 	x, ok := (*m)[int32(xd.Number())]
 	if !ok {
 		return false
 	}
 	switch {
 	case xd.IsList():
 		return x.Value().List().Len() > 0
 	case xd.IsMap():
 		return x.Value().Map().Len() > 0
 	case xd.Message() != nil:
 		return x.Value().Message().IsValid()
 	}
 	return true
 }
 func (m *extensionMap) Clear(xt protoreflect.ExtensionType) {
 	delete(*m, int32(xt.TypeDescriptor().Number()))
 }
 func (m *extensionMap) Get(xt protoreflect.ExtensionType) protoreflect.Value {
 	xd := xt.TypeDescriptor()
 	if m != nil {
 		if x, ok := (*m)[int32(xd.Number())]; ok {
 			return x.Value()
 		}
 	}
 	return xt.Zero()
 }
 func (m *extensionMap) Set(xt protoreflect.ExtensionType, v protoreflect.Value) {
 	xd := xt.TypeDescriptor()
 	isValid := true
 	switch {
 	case !xt.IsValidValue(v):
 		isValid = false
 	case xd.IsList():
 		isValid = v.List().IsValid()
 	case xd.IsMap():
 		isValid = v.Map().IsValid()
 	case xd.Message() != nil:
 		isValid = v.Message().IsValid()
 	}
 	if !isValid {
 		panic(fmt.Sprintf("%v: assigning invalid value", xt.TypeDescriptor().FullName()))
 	}
 
 	if *m == nil {
 		*m = make(map[int32]ExtensionField)
 	}
 	var x ExtensionField
 	x.Set(xt, v)
 	(*m)[int32(xd.Number())] = x
 }
 func (m *extensionMap) Mutable(xt protoreflect.ExtensionType) protoreflect.Value {
 	xd := xt.TypeDescriptor()
 	if xd.Kind() != protoreflect.MessageKind && xd.Kind() != protoreflect.GroupKind && !xd.IsList() && !xd.IsMap() {
 		panic("invalid Mutable on field with non-composite type")
 	}
 	if x, ok := (*m)[int32(xd.Number())]; ok {
 		return x.Value()
 	}
 	v := xt.New()
 	m.Set(xt, v)
 	return v
 }
 
 // MessageState is a data structure that is nested as the first field in a
 // concrete message. It provides a way to implement the ProtoReflect method
 // in an allocation-free way without needing to have a shadow Go type generated
 // for every message type. This technique only works using unsafe.
 //
 // Example generated code:
 //
 //	type M struct {
 //		state protoimpl.MessageState
 //
 //		Field1 int32
 //		Field2 string
 //		Field3 *BarMessage
 //		...
 //	}
 //
 //	func (m *M) ProtoReflect() protoreflect.Message {
 //		mi := &file_fizz_buzz_proto_msgInfos[5]
 //		if protoimpl.UnsafeEnabled && m != nil {
 //			ms := protoimpl.X.MessageStateOf(Pointer(m))
 //			if ms.LoadMessageInfo() == nil {
 //				ms.StoreMessageInfo(mi)
 //			}
 //			return ms
 //		}
 //		return mi.MessageOf(m)
 //	}
 //
 // The MessageState type holds a *MessageInfo, which must be atomically set to
 // the message info associated with a given message instance.
 // By unsafely converting a *M into a *MessageState, the MessageState object
 // has access to all the information needed to implement protobuf reflection.
 // It has access to the message info as its first field, and a pointer to the
 // MessageState is identical to a pointer to the concrete message value.
 //
 // Requirements:
 //   - The type M must implement protoreflect.ProtoMessage.
 //   - The address of m must not be nil.
 //   - The address of m and the address of m.state must be equal,
 //     even though they are different Go types.
 type MessageState struct {
 	pragma.NoUnkeyedLiterals
 	pragma.DoNotCompare
 	pragma.DoNotCopy
 
 	atomicMessageInfo *MessageInfo
 }
 
 type messageState MessageState
 
 var (
 	_ protoreflect.Message = (*messageState)(nil)
 	_ unwrapper            = (*messageState)(nil)
 )
 
 // messageDataType is a tuple of a pointer to the message data and
 // a pointer to the message type. It is a generalized way of providing a
 // reflective view over a message instance. The disadvantage of this approach
 // is the need to allocate this tuple of 16B.
 type messageDataType struct {
 	p  pointer
 	mi *MessageInfo
 }
 
 type (
 	messageReflectWrapper messageDataType
 	messageIfaceWrapper   messageDataType
 )
 
 var (
 	_ protoreflect.Message      = (*messageReflectWrapper)(nil)
 	_ unwrapper                 = (*messageReflectWrapper)(nil)
 	_ protoreflect.ProtoMessage = (*messageIfaceWrapper)(nil)
 	_ unwrapper                 = (*messageIfaceWrapper)(nil)
 )
 
 // MessageOf returns a reflective view over a message. The input must be a
 // pointer to a named Go struct. If the provided type has a ProtoReflect method,
 // it must be implemented by calling this method.
 func (mi *MessageInfo) MessageOf(m interface{}) protoreflect.Message {
 	if reflect.TypeOf(m) != mi.GoReflectType {
 		panic(fmt.Sprintf("type mismatch: got %T, want %v", m, mi.GoReflectType))
 	}
 	p := pointerOfIface(m)
 	if p.IsNil() {
 		return mi.nilMessage.Init(mi)
 	}
 	return &messageReflectWrapper{p, mi}
 }
 
 func (m *messageReflectWrapper) pointer() pointer          { return m.p }
 func (m *messageReflectWrapper) messageInfo() *MessageInfo { return m.mi }
 
 // Reset implements the v1 proto.Message.Reset method.
 func (m *messageIfaceWrapper) Reset() {
 	if mr, ok := m.protoUnwrap().(interface{ Reset() }); ok {
 		mr.Reset()
 		return
 	}
 	rv := reflect.ValueOf(m.protoUnwrap())
 	if rv.Kind() == reflect.Ptr && !rv.IsNil() {
 		rv.Elem().Set(reflect.Zero(rv.Type().Elem()))
 	}
 }
 func (m *messageIfaceWrapper) ProtoReflect() protoreflect.Message {
 	return (*messageReflectWrapper)(m)
 }
 func (m *messageIfaceWrapper) protoUnwrap() interface{} {
 	return m.p.AsIfaceOf(m.mi.GoReflectType.Elem())
 }
 
 // checkField verifies that the provided field descriptor is valid.
 // Exactly one of the returned values is populated.
 func (mi *MessageInfo) checkField(fd protoreflect.FieldDescriptor) (*fieldInfo, protoreflect.ExtensionType) {
 	var fi *fieldInfo
 	if n := fd.Number(); 0 < n && int(n) < len(mi.denseFields) {
 		fi = mi.denseFields[n]
 	} else {
 		fi = mi.fields[n]
 	}
 	if fi != nil {
 		if fi.fieldDesc != fd {
 			if got, want := fd.FullName(), fi.fieldDesc.FullName(); got != want {
 				panic(fmt.Sprintf("mismatching field: got %v, want %v", got, want))
 			}
 			panic(fmt.Sprintf("mismatching field: %v", fd.FullName()))
 		}
 		return fi, nil
 	}
 
 	if fd.IsExtension() {
 		if got, want := fd.ContainingMessage().FullName(), mi.Desc.FullName(); got != want {
 			// TODO: Should this be exact containing message descriptor match?
 			panic(fmt.Sprintf("extension %v has mismatching containing message: got %v, want %v", fd.FullName(), got, want))
 		}
 		if !mi.Desc.ExtensionRanges().Has(fd.Number()) {
 			panic(fmt.Sprintf("extension %v extends %v outside the extension range", fd.FullName(), mi.Desc.FullName()))
 		}
 		xtd, ok := fd.(protoreflect.ExtensionTypeDescriptor)
 		if !ok {
 			panic(fmt.Sprintf("extension %v does not implement protoreflect.ExtensionTypeDescriptor", fd.FullName()))
 		}
 		return nil, xtd.Type()
 	}
 	panic(fmt.Sprintf("field %v is invalid", fd.FullName()))
 }