| // 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/pragma" |
| pref "google.golang.org/protobuf/reflect/protoreflect" |
| ) |
| |
| type reflectMessageInfo struct { |
| fields map[pref.FieldNumber]*fieldInfo |
| oneofs map[pref.Name]*oneofInfo |
| |
| // 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) pref.RawFields |
| setUnknown func(pointer, pref.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) |
| } |
| |
| // 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[pref.FieldNumber]*fieldInfo{} |
| md := mi.Desc |
| fds := md.Fields() |
| for i := 0; i < fds.Len(); i++ { |
| fd := fds.Get(i) |
| fs := si.fieldsByNumber[fd.Number()] |
| var fi fieldInfo |
| switch { |
| case fd.ContainingOneof() != nil: |
| fi = fieldInfoForOneof(fd, si.oneofsByName[fd.ContainingOneof().Name()], 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.Kind() == pref.MessageKind || fd.Kind() == pref.GroupKind: |
| fi = fieldInfoForMessage(fd, fs, mi.Exporter) |
| default: |
| fi = fieldInfoForScalar(fd, fs, mi.Exporter) |
| } |
| mi.fields[fd.Number()] = &fi |
| } |
| |
| mi.oneofs = map[pref.Name]*oneofInfo{} |
| for i := 0; i < md.Oneofs().Len(); i++ { |
| od := md.Oneofs().Get(i) |
| mi.oneofs[od.Name()] = makeOneofInfo(od, si.oneofsByName[od.Name()], mi.Exporter, si.oneofWrappersByType) |
| } |
| |
| 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 { |
| mi.rangeInfos = append(mi.rangeInfos, mi.oneofs[od.Name()]) |
| i += od.Fields().Len() |
| } else { |
| mi.rangeInfos = append(mi.rangeInfos, mi.fields[fd.Number()]) |
| i++ |
| } |
| } |
| } |
| |
| func (mi *MessageInfo) makeUnknownFieldsFunc(t reflect.Type, si structInfo) { |
| mi.getUnknown = func(pointer) pref.RawFields { return nil } |
| mi.setUnknown = func(pointer, pref.RawFields) { return } |
| if si.unknownOffset.IsValid() { |
| mi.getUnknown = func(p pointer) pref.RawFields { |
| if p.IsNil() { |
| return nil |
| } |
| rv := p.Apply(si.unknownOffset).AsValueOf(unknownFieldsType) |
| return pref.RawFields(*rv.Interface().(*[]byte)) |
| } |
| mi.setUnknown = func(p pointer, b pref.RawFields) { |
| if p.IsNil() { |
| panic("invalid SetUnknown on nil Message") |
| } |
| rv := p.Apply(si.unknownOffset).AsValueOf(unknownFieldsType) |
| *rv.Interface().(*[]byte) = []byte(b) |
| } |
| } else { |
| mi.getUnknown = func(pointer) pref.RawFields { |
| return nil |
| } |
| mi.setUnknown = func(p pointer, _ pref.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) |
| } |
| } |
| } |
| |
| type extensionMap map[int32]ExtensionField |
| |
| func (m *extensionMap) Range(f func(pref.FieldDescriptor, pref.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 pref.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 |
| } |
| return true |
| } |
| func (m *extensionMap) Clear(xt pref.ExtensionType) { |
| delete(*m, int32(xt.TypeDescriptor().Number())) |
| } |
| func (m *extensionMap) Get(xt pref.ExtensionType) pref.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 pref.ExtensionType, v pref.Value) { |
| if !xt.IsValidValue(v) { |
| 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(xt.TypeDescriptor().Number())] = x |
| } |
| func (m *extensionMap) Mutable(xt pref.ExtensionType) pref.Value { |
| xd := xt.TypeDescriptor() |
| if xd.Kind() != pref.MessageKind && xd.Kind() != pref.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 |
| |
| mi *MessageInfo |
| } |
| |
| type messageState MessageState |
| |
| var ( |
| _ pref.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 ( |
| _ pref.Message = (*messageReflectWrapper)(nil) |
| _ unwrapper = (*messageReflectWrapper)(nil) |
| _ pref.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{}) pref.Message { |
| // TODO: Switch the input to be an opaque Pointer. |
| 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 } |
| |
| func (m *messageIfaceWrapper) ProtoReflect() pref.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 pref.FieldDescriptor) (*fieldInfo, pref.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 { |
| panic("mismatching field descriptor") |
| } |
| return fi, nil |
| } |
| |
| if fd.IsExtension() { |
| if fd.ContainingMessage().FullName() != mi.Desc.FullName() { |
| // TODO: Should this be exact containing message descriptor match? |
| panic("mismatching containing message") |
| } |
| if !mi.Desc.ExtensionRanges().Has(fd.Number()) { |
| panic("invalid extension field") |
| } |
| xtd, ok := fd.(pref.ExtensionTypeDescriptor) |
| if !ok { |
| panic("extension descriptor does not implement ExtensionTypeDescriptor") |
| } |
| return nil, xtd.Type() |
| } |
| panic("invalid field descriptor") |
| } |