gtsocial-umbx

message.go (8571B)

---

 // 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"
 	"reflect"
 	"strconv"
 	"strings"
 	"sync"
 	"sync/atomic"
 
 	"google.golang.org/protobuf/internal/genid"
 	"google.golang.org/protobuf/reflect/protoreflect"
 	"google.golang.org/protobuf/reflect/protoregistry"
 )
 
 // MessageInfo provides protobuf related functionality for a given Go type
 // that represents a message. A given instance of MessageInfo is tied to
 // exactly one Go type, which must be a pointer to a struct type.
 //
 // The exported fields must be populated before any methods are called
 // and cannot be mutated after set.
 type MessageInfo struct {
 	// GoReflectType is the underlying message Go type and must be populated.
 	GoReflectType reflect.Type // pointer to struct
 
 	// Desc is the underlying message descriptor type and must be populated.
 	Desc protoreflect.MessageDescriptor
 
 	// Exporter must be provided in a purego environment in order to provide
 	// access to unexported fields.
 	Exporter exporter
 
 	// OneofWrappers is list of pointers to oneof wrapper struct types.
 	OneofWrappers []interface{}
 
 	initMu   sync.Mutex // protects all unexported fields
 	initDone uint32
 
 	reflectMessageInfo // for reflection implementation
 	coderMessageInfo   // for fast-path method implementations
 }
 
 // exporter is a function that returns a reference to the ith field of v,
 // where v is a pointer to a struct. It returns nil if it does not support
 // exporting the requested field (e.g., already exported).
 type exporter func(v interface{}, i int) interface{}
 
 // getMessageInfo returns the MessageInfo for any message type that
 // is generated by our implementation of protoc-gen-go (for v2 and on).
 // If it is unable to obtain a MessageInfo, it returns nil.
 func getMessageInfo(mt reflect.Type) *MessageInfo {
 	m, ok := reflect.Zero(mt).Interface().(protoreflect.ProtoMessage)
 	if !ok {
 		return nil
 	}
 	mr, ok := m.ProtoReflect().(interface{ ProtoMessageInfo() *MessageInfo })
 	if !ok {
 		return nil
 	}
 	return mr.ProtoMessageInfo()
 }
 
 func (mi *MessageInfo) init() {
 	// This function is called in the hot path. Inline the sync.Once logic,
 	// since allocating a closure for Once.Do is expensive.
 	// Keep init small to ensure that it can be inlined.
 	if atomic.LoadUint32(&mi.initDone) == 0 {
 		mi.initOnce()
 	}
 }
 
 func (mi *MessageInfo) initOnce() {
 	mi.initMu.Lock()
 	defer mi.initMu.Unlock()
 	if mi.initDone == 1 {
 		return
 	}
 
 	t := mi.GoReflectType
 	if t.Kind() != reflect.Ptr && t.Elem().Kind() != reflect.Struct {
 		panic(fmt.Sprintf("got %v, want *struct kind", t))
 	}
 	t = t.Elem()
 
 	si := mi.makeStructInfo(t)
 	mi.makeReflectFuncs(t, si)
 	mi.makeCoderMethods(t, si)
 
 	atomic.StoreUint32(&mi.initDone, 1)
 }
 
 // getPointer returns the pointer for a message, which should be of
 // the type of the MessageInfo. If the message is of a different type,
 // it returns ok==false.
 func (mi *MessageInfo) getPointer(m protoreflect.Message) (p pointer, ok bool) {
 	switch m := m.(type) {
 	case *messageState:
 		return m.pointer(), m.messageInfo() == mi
 	case *messageReflectWrapper:
 		return m.pointer(), m.messageInfo() == mi
 	}
 	return pointer{}, false
 }
 
 type (
 	SizeCache       = int32
 	WeakFields      = map[int32]protoreflect.ProtoMessage
 	UnknownFields   = unknownFieldsA // TODO: switch to unknownFieldsB
 	unknownFieldsA  = []byte
 	unknownFieldsB  = *[]byte
 	ExtensionFields = map[int32]ExtensionField
 )
 
 var (
 	sizecacheType       = reflect.TypeOf(SizeCache(0))
 	weakFieldsType      = reflect.TypeOf(WeakFields(nil))
 	unknownFieldsAType  = reflect.TypeOf(unknownFieldsA(nil))
 	unknownFieldsBType  = reflect.TypeOf(unknownFieldsB(nil))
 	extensionFieldsType = reflect.TypeOf(ExtensionFields(nil))
 )
 
 type structInfo struct {
 	sizecacheOffset offset
 	sizecacheType   reflect.Type
 	weakOffset      offset
 	weakType        reflect.Type
 	unknownOffset   offset
 	unknownType     reflect.Type
 	extensionOffset offset
 	extensionType   reflect.Type
 
 	fieldsByNumber        map[protoreflect.FieldNumber]reflect.StructField
 	oneofsByName          map[protoreflect.Name]reflect.StructField
 	oneofWrappersByType   map[reflect.Type]protoreflect.FieldNumber
 	oneofWrappersByNumber map[protoreflect.FieldNumber]reflect.Type
 }
 
 func (mi *MessageInfo) makeStructInfo(t reflect.Type) structInfo {
 	si := structInfo{
 		sizecacheOffset: invalidOffset,
 		weakOffset:      invalidOffset,
 		unknownOffset:   invalidOffset,
 		extensionOffset: invalidOffset,
 
 		fieldsByNumber:        map[protoreflect.FieldNumber]reflect.StructField{},
 		oneofsByName:          map[protoreflect.Name]reflect.StructField{},
 		oneofWrappersByType:   map[reflect.Type]protoreflect.FieldNumber{},
 		oneofWrappersByNumber: map[protoreflect.FieldNumber]reflect.Type{},
 	}
 
 fieldLoop:
 	for i := 0; i < t.NumField(); i++ {
 		switch f := t.Field(i); f.Name {
 		case genid.SizeCache_goname, genid.SizeCacheA_goname:
 			if f.Type == sizecacheType {
 				si.sizecacheOffset = offsetOf(f, mi.Exporter)
 				si.sizecacheType = f.Type
 			}
 		case genid.WeakFields_goname, genid.WeakFieldsA_goname:
 			if f.Type == weakFieldsType {
 				si.weakOffset = offsetOf(f, mi.Exporter)
 				si.weakType = f.Type
 			}
 		case genid.UnknownFields_goname, genid.UnknownFieldsA_goname:
 			if f.Type == unknownFieldsAType || f.Type == unknownFieldsBType {
 				si.unknownOffset = offsetOf(f, mi.Exporter)
 				si.unknownType = f.Type
 			}
 		case genid.ExtensionFields_goname, genid.ExtensionFieldsA_goname, genid.ExtensionFieldsB_goname:
 			if f.Type == extensionFieldsType {
 				si.extensionOffset = offsetOf(f, mi.Exporter)
 				si.extensionType = f.Type
 			}
 		default:
 			for _, s := range strings.Split(f.Tag.Get("protobuf"), ",") {
 				if len(s) > 0 && strings.Trim(s, "0123456789") == "" {
 					n, _ := strconv.ParseUint(s, 10, 64)
 					si.fieldsByNumber[protoreflect.FieldNumber(n)] = f
 					continue fieldLoop
 				}
 			}
 			if s := f.Tag.Get("protobuf_oneof"); len(s) > 0 {
 				si.oneofsByName[protoreflect.Name(s)] = f
 				continue fieldLoop
 			}
 		}
 	}
 
 	// Derive a mapping of oneof wrappers to fields.
 	oneofWrappers := mi.OneofWrappers
 	for _, method := range []string{"XXX_OneofFuncs", "XXX_OneofWrappers"} {
 		if fn, ok := reflect.PtrTo(t).MethodByName(method); ok {
 			for _, v := range fn.Func.Call([]reflect.Value{reflect.Zero(fn.Type.In(0))}) {
 				if vs, ok := v.Interface().([]interface{}); ok {
 					oneofWrappers = vs
 				}
 			}
 		}
 	}
 	for _, v := range oneofWrappers {
 		tf := reflect.TypeOf(v).Elem()
 		f := tf.Field(0)
 		for _, s := range strings.Split(f.Tag.Get("protobuf"), ",") {
 			if len(s) > 0 && strings.Trim(s, "0123456789") == "" {
 				n, _ := strconv.ParseUint(s, 10, 64)
 				si.oneofWrappersByType[tf] = protoreflect.FieldNumber(n)
 				si.oneofWrappersByNumber[protoreflect.FieldNumber(n)] = tf
 				break
 			}
 		}
 	}
 
 	return si
 }
 
 func (mi *MessageInfo) New() protoreflect.Message {
 	m := reflect.New(mi.GoReflectType.Elem()).Interface()
 	if r, ok := m.(protoreflect.ProtoMessage); ok {
 		return r.ProtoReflect()
 	}
 	return mi.MessageOf(m)
 }
 func (mi *MessageInfo) Zero() protoreflect.Message {
 	return mi.MessageOf(reflect.Zero(mi.GoReflectType).Interface())
 }
 func (mi *MessageInfo) Descriptor() protoreflect.MessageDescriptor {
 	return mi.Desc
 }
 func (mi *MessageInfo) Enum(i int) protoreflect.EnumType {
 	mi.init()
 	fd := mi.Desc.Fields().Get(i)
 	return Export{}.EnumTypeOf(mi.fieldTypes[fd.Number()])
 }
 func (mi *MessageInfo) Message(i int) protoreflect.MessageType {
 	mi.init()
 	fd := mi.Desc.Fields().Get(i)
 	switch {
 	case fd.IsWeak():
 		mt, _ := protoregistry.GlobalTypes.FindMessageByName(fd.Message().FullName())
 		return mt
 	case fd.IsMap():
 		return mapEntryType{fd.Message(), mi.fieldTypes[fd.Number()]}
 	default:
 		return Export{}.MessageTypeOf(mi.fieldTypes[fd.Number()])
 	}
 }
 
 type mapEntryType struct {
 	desc    protoreflect.MessageDescriptor
 	valType interface{} // zero value of enum or message type
 }
 
 func (mt mapEntryType) New() protoreflect.Message {
 	return nil
 }
 func (mt mapEntryType) Zero() protoreflect.Message {
 	return nil
 }
 func (mt mapEntryType) Descriptor() protoreflect.MessageDescriptor {
 	return mt.desc
 }
 func (mt mapEntryType) Enum(i int) protoreflect.EnumType {
 	fd := mt.desc.Fields().Get(i)
 	if fd.Enum() == nil {
 		return nil
 	}
 	return Export{}.EnumTypeOf(mt.valType)
 }
 func (mt mapEntryType) Message(i int) protoreflect.MessageType {
 	fd := mt.desc.Fields().Get(i)
 	if fd.Message() == nil {
 		return nil
 	}
 	return Export{}.MessageTypeOf(mt.valType)
 }