1 // Go support for Protocol Buffers - Google's data interchange format
3 // Copyright 2010 The Go Authors. All rights reserved.
4 // https://github.com/golang/protobuf
6 // Redistribution and use in source and binary forms, with or without
7 // modification, are permitted provided that the following conditions are
10 // * Redistributions of source code must retain the above copyright
11 // notice, this list of conditions and the following disclaimer.
12 // * Redistributions in binary form must reproduce the above
13 // copyright notice, this list of conditions and the following disclaimer
14 // in the documentation and/or other materials provided with the
16 // * Neither the name of Google Inc. nor the names of its
17 // contributors may be used to endorse or promote products derived from
18 // this software without specific prior written permission.
20 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 Package proto converts data structures to and from the wire format of
34 protocol buffers. It works in concert with the Go source code generated
35 for .proto files by the protocol compiler.
37 A summary of the properties of the protocol buffer interface
38 for a protocol buffer variable v:
40 - Names are turned from camel_case to CamelCase for export.
41 - There are no methods on v to set fields; just treat
42 them as structure fields.
43 - There are getters that return a field's value if set,
44 and return the field's default value if unset.
45 The getters work even if the receiver is a nil message.
46 - The zero value for a struct is its correct initialization state.
47 All desired fields must be set before marshaling.
48 - A Reset() method will restore a protobuf struct to its zero state.
49 - Non-repeated fields are pointers to the values; nil means unset.
50 That is, optional or required field int32 f becomes F *int32.
51 - Repeated fields are slices.
52 - Helper functions are available to aid the setting of fields.
53 msg.Foo = proto.String("hello") // set field
54 - Constants are defined to hold the default values of all fields that
55 have them. They have the form Default_StructName_FieldName.
56 Because the getter methods handle defaulted values,
57 direct use of these constants should be rare.
58 - Enums are given type names and maps from names to values.
59 Enum values are prefixed by the enclosing message's name, or by the
60 enum's type name if it is a top-level enum. Enum types have a String
61 method, and a Enum method to assist in message construction.
62 - Nested messages, groups and enums have type names prefixed with the name of
63 the surrounding message type.
64 - Extensions are given descriptor names that start with E_,
65 followed by an underscore-delimited list of the nested messages
66 that contain it (if any) followed by the CamelCased name of the
67 extension field itself. HasExtension, ClearExtension, GetExtension
68 and SetExtension are functions for manipulating extensions.
69 - Oneof field sets are given a single field in their message,
70 with distinguished wrapper types for each possible field value.
71 - Marshal and Unmarshal are functions to encode and decode the wire format.
73 When the .proto file specifies `syntax="proto3"`, there are some differences:
75 - Non-repeated fields of non-message type are values instead of pointers.
76 - Enum types do not get an Enum method.
78 The simplest way to describe this is to see an example.
79 Given file test.proto, containing
86 required string label = 1;
87 optional int32 type = 2 [default=77];
88 repeated int64 reps = 3;
89 optional group OptionalGroup = 4 {
90 required string RequiredField = 5;
98 The resulting file, test.pb.go, is:
102 import proto "github.com/golang/protobuf/proto"
109 var FOO_name = map[int32]string{
112 var FOO_value = map[string]int32{
116 func (x FOO) Enum() *FOO {
121 func (x FOO) String() string {
122 return proto.EnumName(FOO_name, int32(x))
124 func (x *FOO) UnmarshalJSON(data []byte) error {
125 value, err := proto.UnmarshalJSONEnum(FOO_value, data)
134 Label *string `protobuf:"bytes,1,req,name=label" json:"label,omitempty"`
135 Type *int32 `protobuf:"varint,2,opt,name=type,def=77" json:"type,omitempty"`
136 Reps []int64 `protobuf:"varint,3,rep,name=reps" json:"reps,omitempty"`
137 Optionalgroup *Test_OptionalGroup `protobuf:"group,4,opt,name=OptionalGroup" json:"optionalgroup,omitempty"`
138 // Types that are valid to be assigned to Union:
141 Union isTest_Union `protobuf_oneof:"union"`
142 XXX_unrecognized []byte `json:"-"`
144 func (m *Test) Reset() { *m = Test{} }
145 func (m *Test) String() string { return proto.CompactTextString(m) }
146 func (*Test) ProtoMessage() {}
148 type isTest_Union interface {
152 type Test_Number struct {
153 Number int32 `protobuf:"varint,6,opt,name=number"`
155 type Test_Name struct {
156 Name string `protobuf:"bytes,7,opt,name=name"`
159 func (*Test_Number) isTest_Union() {}
160 func (*Test_Name) isTest_Union() {}
162 func (m *Test) GetUnion() isTest_Union {
168 const Default_Test_Type int32 = 77
170 func (m *Test) GetLabel() string {
171 if m != nil && m.Label != nil {
177 func (m *Test) GetType() int32 {
178 if m != nil && m.Type != nil {
181 return Default_Test_Type
184 func (m *Test) GetOptionalgroup() *Test_OptionalGroup {
186 return m.Optionalgroup
191 type Test_OptionalGroup struct {
192 RequiredField *string `protobuf:"bytes,5,req" json:"RequiredField,omitempty"`
194 func (m *Test_OptionalGroup) Reset() { *m = Test_OptionalGroup{} }
195 func (m *Test_OptionalGroup) String() string { return proto.CompactTextString(m) }
197 func (m *Test_OptionalGroup) GetRequiredField() string {
198 if m != nil && m.RequiredField != nil {
199 return *m.RequiredField
204 func (m *Test) GetNumber() int32 {
205 if x, ok := m.GetUnion().(*Test_Number); ok {
211 func (m *Test) GetName() string {
212 if x, ok := m.GetUnion().(*Test_Name); ok {
219 proto.RegisterEnum("example.FOO", FOO_name, FOO_value)
222 To create and play with a Test object:
229 "github.com/golang/protobuf/proto"
235 Label: proto.String("hello"),
236 Type: proto.Int32(17),
237 Reps: []int64{1, 2, 3},
238 Optionalgroup: &pb.Test_OptionalGroup{
239 RequiredField: proto.String("good bye"),
241 Union: &pb.Test_Name{"fred"},
243 data, err := proto.Marshal(test)
245 log.Fatal("marshaling error: ", err)
247 newTest := &pb.Test{}
248 err = proto.Unmarshal(data, newTest)
250 log.Fatal("unmarshaling error: ", err)
252 // Now test and newTest contain the same data.
253 if test.GetLabel() != newTest.GetLabel() {
254 log.Fatalf("data mismatch %q != %q", test.GetLabel(), newTest.GetLabel())
256 // Use a type switch to determine which oneof was set.
257 switch u := test.Union.(type) {
258 case *pb.Test_Number: // u.Number contains the number.
259 case *pb.Test_Name: // u.Name contains the string.
276 // RequiredNotSetError is an error type returned by either Marshal or Unmarshal.
277 // Marshal reports this when a required field is not initialized.
278 // Unmarshal reports this when a required field is missing from the wire data.
279 type RequiredNotSetError struct{ field string }
281 func (e *RequiredNotSetError) Error() string {
283 return fmt.Sprintf("proto: required field not set")
285 return fmt.Sprintf("proto: required field %q not set", e.field)
287 func (e *RequiredNotSetError) RequiredNotSet() bool {
291 type invalidUTF8Error struct{ field string }
293 func (e *invalidUTF8Error) Error() string {
295 return "proto: invalid UTF-8 detected"
297 return fmt.Sprintf("proto: field %q contains invalid UTF-8", e.field)
299 func (e *invalidUTF8Error) InvalidUTF8() bool {
303 // errInvalidUTF8 is a sentinel error to identify fields with invalid UTF-8.
304 // This error should not be exposed to the external API as such errors should
305 // be recreated with the field information.
306 var errInvalidUTF8 = &invalidUTF8Error{}
308 // isNonFatal reports whether the error is either a RequiredNotSet error
309 // or a InvalidUTF8 error.
310 func isNonFatal(err error) bool {
311 if re, ok := err.(interface{ RequiredNotSet() bool }); ok && re.RequiredNotSet() {
314 if re, ok := err.(interface{ InvalidUTF8() bool }); ok && re.InvalidUTF8() {
320 type nonFatal struct{ E error }
322 // Merge merges err into nf and reports whether it was successful.
323 // Otherwise it returns false for any fatal non-nil errors.
324 func (nf *nonFatal) Merge(err error) (ok bool) {
326 return true // not an error
328 if !isNonFatal(err) {
329 return false // fatal error
332 nf.E = err // store first instance of non-fatal error
337 // Message is implemented by generated protocol buffer messages.
338 type Message interface {
344 // A Buffer is a buffer manager for marshaling and unmarshaling
345 // protocol buffers. It may be reused between invocations to
346 // reduce memory usage. It is not necessary to use a Buffer;
347 // the global functions Marshal and Unmarshal create a
348 // temporary Buffer and are fine for most applications.
350 buf []byte // encode/decode byte stream
351 index int // read point
356 // NewBuffer allocates a new Buffer and initializes its internal data to
357 // the contents of the argument slice.
358 func NewBuffer(e []byte) *Buffer {
359 return &Buffer{buf: e}
362 // Reset resets the Buffer, ready for marshaling a new protocol buffer.
363 func (p *Buffer) Reset() {
364 p.buf = p.buf[0:0] // for reading/writing
365 p.index = 0 // for reading
368 // SetBuf replaces the internal buffer with the slice,
369 // ready for unmarshaling the contents of the slice.
370 func (p *Buffer) SetBuf(s []byte) {
375 // Bytes returns the contents of the Buffer.
376 func (p *Buffer) Bytes() []byte { return p.buf }
378 // SetDeterministic sets whether to use deterministic serialization.
380 // Deterministic serialization guarantees that for a given binary, equal
381 // messages will always be serialized to the same bytes. This implies:
383 // - Repeated serialization of a message will return the same bytes.
384 // - Different processes of the same binary (which may be executing on
385 // different machines) will serialize equal messages to the same bytes.
387 // Note that the deterministic serialization is NOT canonical across
388 // languages. It is not guaranteed to remain stable over time. It is unstable
389 // across different builds with schema changes due to unknown fields.
390 // Users who need canonical serialization (e.g., persistent storage in a
391 // canonical form, fingerprinting, etc.) should define their own
392 // canonicalization specification and implement their own serializer rather
393 // than relying on this API.
395 // If deterministic serialization is requested, map entries will be sorted
396 // by keys in lexographical order. This is an implementation detail and
397 // subject to change.
398 func (p *Buffer) SetDeterministic(deterministic bool) {
399 p.deterministic = deterministic
403 * Helper routines for simplifying the creation of optional fields of basic type.
406 // Bool is a helper routine that allocates a new bool value
407 // to store v and returns a pointer to it.
408 func Bool(v bool) *bool {
412 // Int32 is a helper routine that allocates a new int32 value
413 // to store v and returns a pointer to it.
414 func Int32(v int32) *int32 {
418 // Int is a helper routine that allocates a new int32 value
419 // to store v and returns a pointer to it, but unlike Int32
420 // its argument value is an int.
421 func Int(v int) *int32 {
427 // Int64 is a helper routine that allocates a new int64 value
428 // to store v and returns a pointer to it.
429 func Int64(v int64) *int64 {
433 // Float32 is a helper routine that allocates a new float32 value
434 // to store v and returns a pointer to it.
435 func Float32(v float32) *float32 {
439 // Float64 is a helper routine that allocates a new float64 value
440 // to store v and returns a pointer to it.
441 func Float64(v float64) *float64 {
445 // Uint32 is a helper routine that allocates a new uint32 value
446 // to store v and returns a pointer to it.
447 func Uint32(v uint32) *uint32 {
451 // Uint64 is a helper routine that allocates a new uint64 value
452 // to store v and returns a pointer to it.
453 func Uint64(v uint64) *uint64 {
457 // String is a helper routine that allocates a new string value
458 // to store v and returns a pointer to it.
459 func String(v string) *string {
463 // EnumName is a helper function to simplify printing protocol buffer enums
464 // by name. Given an enum map and a value, it returns a useful string.
465 func EnumName(m map[int32]string, v int32) string {
470 return strconv.Itoa(int(v))
473 // UnmarshalJSONEnum is a helper function to simplify recovering enum int values
474 // from their JSON-encoded representation. Given a map from the enum's symbolic
475 // names to its int values, and a byte buffer containing the JSON-encoded
476 // value, it returns an int32 that can be cast to the enum type by the caller.
478 // The function can deal with both JSON representations, numeric and symbolic.
479 func UnmarshalJSONEnum(m map[string]int32, data []byte, enumName string) (int32, error) {
481 // New style: enums are strings.
483 if err := json.Unmarshal(data, &repr); err != nil {
488 return 0, fmt.Errorf("unrecognized enum %s value %q", enumName, repr)
492 // Old style: enums are ints.
494 if err := json.Unmarshal(data, &val); err != nil {
495 return 0, fmt.Errorf("cannot unmarshal %#q into enum %s", data, enumName)
500 // DebugPrint dumps the encoded data in b in a debugging format with a header
501 // including the string s. Used in testing but made available for general debugging.
502 func (p *Buffer) DebugPrint(s string, b []byte) {
511 fmt.Printf("\n--- %s ---\n", s)
515 for i := 0; i < depth; i++ {
520 if index == len(p.buf) {
524 op, err := p.DecodeVarint()
526 fmt.Printf("%3d: fetching op err %v\n", index, err)
534 fmt.Printf("%3d: t=%3d unknown wire=%d\n",
541 r, err = p.DecodeRawBytes(false)
545 fmt.Printf("%3d: t=%3d bytes [%d]", index, tag, len(r))
547 for i := 0; i < len(r); i++ {
548 fmt.Printf(" %.2x", r[i])
551 for i := 0; i < 3; i++ {
552 fmt.Printf(" %.2x", r[i])
555 for i := len(r) - 3; i < len(r); i++ {
556 fmt.Printf(" %.2x", r[i])
562 u, err = p.DecodeFixed32()
564 fmt.Printf("%3d: t=%3d fix32 err %v\n", index, tag, err)
567 fmt.Printf("%3d: t=%3d fix32 %d\n", index, tag, u)
570 u, err = p.DecodeFixed64()
572 fmt.Printf("%3d: t=%3d fix64 err %v\n", index, tag, err)
575 fmt.Printf("%3d: t=%3d fix64 %d\n", index, tag, u)
578 u, err = p.DecodeVarint()
580 fmt.Printf("%3d: t=%3d varint err %v\n", index, tag, err)
583 fmt.Printf("%3d: t=%3d varint %d\n", index, tag, u)
586 fmt.Printf("%3d: t=%3d start\n", index, tag)
591 fmt.Printf("%3d: t=%3d end\n", index, tag)
596 fmt.Printf("%3d: start-end not balanced %d\n", p.index, depth)
604 // SetDefaults sets unset protocol buffer fields to their default values.
605 // It only modifies fields that are both unset and have defined defaults.
606 // It recursively sets default values in any non-nil sub-messages.
607 func SetDefaults(pb Message) {
608 setDefaults(reflect.ValueOf(pb), true, false)
611 // v is a pointer to a struct.
612 func setDefaults(v reflect.Value, recur, zeros bool) {
616 dm, ok := defaults[v.Type()]
619 dm = buildDefaultMessage(v.Type())
621 defaults[v.Type()] = dm
625 for _, sf := range dm.scalars {
626 f := v.Field(sf.index)
632 if dv == nil && !zeros {
633 // no explicit default, and don't want to set zeros
636 fptr := f.Addr().Interface() // **T
637 // TODO: Consider batching the allocations we do here.
645 case reflect.Float32:
650 *(fptr.(**float32)) = f
651 case reflect.Float64:
656 *(fptr.(**float64)) = f
659 if ft := f.Type(); ft != int32PtrType {
661 f.Set(reflect.New(ft.Elem()))
663 f.Elem().SetInt(int64(dv.(int32)))
671 *(fptr.(**int32)) = i
678 *(fptr.(**int64)) = i
684 *(fptr.(**string)) = s
686 // exceptional case: []byte
690 b = make([]byte, len(db))
695 *(fptr.(*[]byte)) = b
701 *(fptr.(**uint32)) = u
707 *(fptr.(**uint64)) = u
709 log.Printf("proto: can't set default for field %v (sf.kind=%v)", f, sf.kind)
713 for _, ni := range dm.nested {
715 // f is *T or []*T or map[T]*T
721 setDefaults(f, recur, zeros)
724 for i := 0; i < f.Len(); i++ {
729 setDefaults(e, recur, zeros)
733 for _, k := range f.MapKeys() {
738 setDefaults(e, recur, zeros)
745 // defaults maps a protocol buffer struct type to a slice of the fields,
746 // with its scalar fields set to their proto-declared non-zero default values.
747 defaultMu sync.RWMutex
748 defaults = make(map[reflect.Type]defaultMessage)
750 int32PtrType = reflect.TypeOf((*int32)(nil))
753 // defaultMessage represents information about the default values of a message.
754 type defaultMessage struct {
755 scalars []scalarField
756 nested []int // struct field index of nested messages
759 type scalarField struct {
760 index int // struct field index
761 kind reflect.Kind // element type (the T in *T or []T)
762 value interface{} // the proto-declared default value, or nil
765 // t is a struct type.
766 func buildDefaultMessage(t reflect.Type) (dm defaultMessage) {
767 sprop := GetProperties(t)
768 for _, prop := range sprop.Prop {
769 fi, ok := sprop.decoderTags.get(prop.Tag)
774 ft := t.Field(fi).Type
776 sf, nested, err := fieldDefault(ft, prop)
781 dm.nested = append(dm.nested, fi)
784 dm.scalars = append(dm.scalars, *sf)
791 // fieldDefault returns the scalarField for field type ft.
792 // sf will be nil if the field can not have a default.
793 // nestedMessage will be true if this is a nested message.
794 // Note that sf.index is not set on return.
795 func fieldDefault(ft reflect.Type, prop *Properties) (sf *scalarField, nestedMessage bool, err error) {
796 var canHaveDefault bool
799 if ft.Elem().Kind() == reflect.Struct {
802 canHaveDefault = true // proto2 scalar field
806 switch ft.Elem().Kind() {
808 nestedMessage = true // repeated message
810 canHaveDefault = true // bytes field
814 if ft.Elem().Kind() == reflect.Ptr {
815 nestedMessage = true // map with message values
821 return nil, true, nil
823 return nil, false, nil
826 // We now know that ft is a pointer or slice.
827 sf = &scalarField{kind: ft.Elem().Kind()}
829 // scalar fields without defaults
830 if !prop.HasDefault {
831 return sf, false, nil
834 // a scalar field: either *T or []byte
835 switch ft.Elem().Kind() {
837 x, err := strconv.ParseBool(prop.Default)
839 return nil, false, fmt.Errorf("proto: bad default bool %q: %v", prop.Default, err)
842 case reflect.Float32:
843 x, err := strconv.ParseFloat(prop.Default, 32)
845 return nil, false, fmt.Errorf("proto: bad default float32 %q: %v", prop.Default, err)
847 sf.value = float32(x)
848 case reflect.Float64:
849 x, err := strconv.ParseFloat(prop.Default, 64)
851 return nil, false, fmt.Errorf("proto: bad default float64 %q: %v", prop.Default, err)
855 x, err := strconv.ParseInt(prop.Default, 10, 32)
857 return nil, false, fmt.Errorf("proto: bad default int32 %q: %v", prop.Default, err)
861 x, err := strconv.ParseInt(prop.Default, 10, 64)
863 return nil, false, fmt.Errorf("proto: bad default int64 %q: %v", prop.Default, err)
867 sf.value = prop.Default
869 // []byte (not *uint8)
870 sf.value = []byte(prop.Default)
872 x, err := strconv.ParseUint(prop.Default, 10, 32)
874 return nil, false, fmt.Errorf("proto: bad default uint32 %q: %v", prop.Default, err)
878 x, err := strconv.ParseUint(prop.Default, 10, 64)
880 return nil, false, fmt.Errorf("proto: bad default uint64 %q: %v", prop.Default, err)
884 return nil, false, fmt.Errorf("proto: unhandled def kind %v", ft.Elem().Kind())
887 return sf, false, nil
890 // mapKeys returns a sort.Interface to be used for sorting the map keys.
891 // Map fields may have key types of non-float scalars, strings and enums.
892 func mapKeys(vs []reflect.Value) sort.Interface {
893 s := mapKeySorter{vs: vs}
895 // Type specialization per https://developers.google.com/protocol-buffers/docs/proto#maps.
899 switch vs[0].Kind() {
900 case reflect.Int32, reflect.Int64:
901 s.less = func(a, b reflect.Value) bool { return a.Int() < b.Int() }
902 case reflect.Uint32, reflect.Uint64:
903 s.less = func(a, b reflect.Value) bool { return a.Uint() < b.Uint() }
905 s.less = func(a, b reflect.Value) bool { return !a.Bool() && b.Bool() } // false < true
907 s.less = func(a, b reflect.Value) bool { return a.String() < b.String() }
909 panic(fmt.Sprintf("unsupported map key type: %v", vs[0].Kind()))
915 type mapKeySorter struct {
917 less func(a, b reflect.Value) bool
920 func (s mapKeySorter) Len() int { return len(s.vs) }
921 func (s mapKeySorter) Swap(i, j int) { s.vs[i], s.vs[j] = s.vs[j], s.vs[i] }
922 func (s mapKeySorter) Less(i, j int) bool {
923 return s.less(s.vs[i], s.vs[j])
926 // isProto3Zero reports whether v is a zero proto3 value.
927 func isProto3Zero(v reflect.Value) bool {
931 case reflect.Int32, reflect.Int64:
933 case reflect.Uint32, reflect.Uint64:
935 case reflect.Float32, reflect.Float64:
936 return v.Float() == 0
938 return v.String() == ""
944 // ProtoPackageIsVersion3 is referenced from generated protocol buffer files
945 // to assert that that code is compatible with this version of the proto package.
946 ProtoPackageIsVersion3 = true
948 // ProtoPackageIsVersion2 is referenced from generated protocol buffer files
949 // to assert that that code is compatible with this version of the proto package.
950 ProtoPackageIsVersion2 = true
952 // ProtoPackageIsVersion1 is referenced from generated protocol buffer files
953 // to assert that that code is compatible with this version of the proto package.
954 ProtoPackageIsVersion1 = true
957 // InternalMessageInfo is a type used internally by generated .pb.go files.
958 // This type is not intended to be used by non-generated code.
959 // This type is not subject to any compatibility guarantee.
960 type InternalMessageInfo struct {
962 unmarshal *unmarshalInfo