diff options
Diffstat (limited to 'vendor/google.golang.org/protobuf/internal/impl/message.go')
-rw-r--r-- | vendor/google.golang.org/protobuf/internal/impl/message.go | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/vendor/google.golang.org/protobuf/internal/impl/message.go b/vendor/google.golang.org/protobuf/internal/impl/message.go new file mode 100644 index 00000000..7dd994bd --- /dev/null +++ b/vendor/google.golang.org/protobuf/internal/impl/message.go @@ -0,0 +1,215 @@ +// 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/genname" + "google.golang.org/protobuf/reflect/protoreflect" + pref "google.golang.org/protobuf/reflect/protoreflect" +) + +// 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 pref.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().(pref.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 pref.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 = []byte + ExtensionFields = map[int32]ExtensionField +) + +var ( + sizecacheType = reflect.TypeOf(SizeCache(0)) + weakFieldsType = reflect.TypeOf(WeakFields(nil)) + unknownFieldsType = reflect.TypeOf(UnknownFields(nil)) + extensionFieldsType = reflect.TypeOf(ExtensionFields(nil)) +) + +type structInfo struct { + sizecacheOffset offset + weakOffset offset + unknownOffset offset + extensionOffset offset + + fieldsByNumber map[pref.FieldNumber]reflect.StructField + oneofsByName map[pref.Name]reflect.StructField + oneofWrappersByType map[reflect.Type]pref.FieldNumber + oneofWrappersByNumber map[pref.FieldNumber]reflect.Type +} + +func (mi *MessageInfo) makeStructInfo(t reflect.Type) structInfo { + si := structInfo{ + sizecacheOffset: invalidOffset, + weakOffset: invalidOffset, + unknownOffset: invalidOffset, + extensionOffset: invalidOffset, + + fieldsByNumber: map[pref.FieldNumber]reflect.StructField{}, + oneofsByName: map[pref.Name]reflect.StructField{}, + oneofWrappersByType: map[reflect.Type]pref.FieldNumber{}, + oneofWrappersByNumber: map[pref.FieldNumber]reflect.Type{}, + } + +fieldLoop: + for i := 0; i < t.NumField(); i++ { + switch f := t.Field(i); f.Name { + case genname.SizeCache, genname.SizeCacheA: + if f.Type == sizecacheType { + si.sizecacheOffset = offsetOf(f, mi.Exporter) + } + case genname.WeakFields, genname.WeakFieldsA: + if f.Type == weakFieldsType { + si.weakOffset = offsetOf(f, mi.Exporter) + } + case genname.UnknownFields, genname.UnknownFieldsA: + if f.Type == unknownFieldsType { + si.unknownOffset = offsetOf(f, mi.Exporter) + } + case genname.ExtensionFields, genname.ExtensionFieldsA, genname.ExtensionFieldsB: + if f.Type == extensionFieldsType { + si.extensionOffset = offsetOf(f, mi.Exporter) + } + 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[pref.FieldNumber(n)] = f + continue fieldLoop + } + } + if s := f.Tag.Get("protobuf_oneof"); len(s) > 0 { + si.oneofsByName[pref.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] = pref.FieldNumber(n) + si.oneofWrappersByNumber[pref.FieldNumber(n)] = tf + break + } + } + } + + return si +} + +func (mi *MessageInfo) New() protoreflect.Message { + return mi.MessageOf(reflect.New(mi.GoReflectType.Elem()).Interface()) +} +func (mi *MessageInfo) Zero() protoreflect.Message { + return mi.MessageOf(reflect.Zero(mi.GoReflectType).Interface()) +} +func (mi *MessageInfo) Descriptor() protoreflect.MessageDescriptor { return mi.Desc } |