proto/message_set.go - third_party/golang/protobuf - Git at Google

 // Go support for Protocol Buffers - Google's data interchange format
 //
 // Copyright 2010 The Go Authors.  All rights reserved.
 // https://github.com/golang/protobuf
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 // copyright notice, this list of conditions and the following disclaimer
 // in the documentation and/or other materials provided with the
 // distribution.
 //     * Neither the name of Google Inc. nor the names of its
 // contributors may be used to endorse or promote products derived from
 // this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 package proto

 /*
  * Support for message sets.
  */

 import (
 	"bytes"
 	"encoding/json"
 	"errors"
 	"fmt"
 	"reflect"
 	"sort"
 )

 // errNoMessageTypeID occurs when a protocol buffer does not have a message type ID.
 // A message type ID is required for storing a protocol buffer in a message set.
 var errNoMessageTypeID = errors.New("proto does not have a message type ID")

 // The first two types (_MessageSet_Item and messageSet)
 // model what the protocol compiler produces for the following protocol message:
 //   message MessageSet {
 //     repeated group Item = 1 {
 //       required int32 type_id = 2;
 //       required string message = 3;
 //     };
 //   }
 // That is the MessageSet wire format. We can't use a proto to generate these
 // because that would introduce a circular dependency between it and this package.

 type _MessageSet_Item struct {
 	TypeId  *int32 `protobuf:"varint,2,req,name=type_id"`
 	Message []byte `protobuf:"bytes,3,req,name=message"`
 }

 type messageSet struct {
 	Item             []*_MessageSet_Item `protobuf:"group,1,rep"`
 	XXX_unrecognized []byte
 	// TODO: caching?
 }

 // Make sure messageSet is a Message.
 var _ Message = (*messageSet)(nil)

 // messageTypeIder is an interface satisfied by a protocol buffer type
 // that may be stored in a MessageSet.
 type messageTypeIder interface {
 	MessageTypeId() int32
 }

 func (ms *messageSet) find(pb Message) *_MessageSet_Item {
 	mti, ok := pb.(messageTypeIder)
 	if !ok {
 		return nil
 	}
 	id := mti.MessageTypeId()
 	for _, item := range ms.Item {
 		if *item.TypeId == id {
 			return item
 		}
 	}
 	return nil
 }

 func (ms *messageSet) Has(pb Message) bool {
 	if ms.find(pb) != nil {
 		return true
 	}
 	return false
 }

 func (ms *messageSet) Unmarshal(pb Message) error {
 	if item := ms.find(pb); item != nil {
 		return Unmarshal(item.Message, pb)
 	}
 	if _, ok := pb.(messageTypeIder); !ok {
 		return errNoMessageTypeID
 	}
 	return nil // TODO: return error instead?
 }

 func (ms *messageSet) Marshal(pb Message) error {
 	msg, err := Marshal(pb)
 	if err != nil {
 		return err
 	}
 	if item := ms.find(pb); item != nil {
 		// reuse existing item
 		item.Message = msg
 		return nil
 	}

 	mti, ok := pb.(messageTypeIder)
 	if !ok {
 		return errNoMessageTypeID
 	}

 	mtid := mti.MessageTypeId()
 	ms.Item = append(ms.Item, &_MessageSet_Item{
 		TypeId:  &mtid,
 		Message: msg,
 	})
 	return nil
 }

 func (ms *messageSet) Reset()         { *ms = messageSet{} }
 func (ms *messageSet) String() string { return CompactTextString(ms) }
 func (*messageSet) ProtoMessage()     {}

 // Support for the message_set_wire_format message option.

 func skipVarint(buf []byte) []byte {
 	i := 0
 	for ; buf[i]&0x80 != 0; i++ {
 	}
 	return buf[i+1:]
 }

 // MarshalMessageSet encodes the extension map represented by m in the message set wire format.
 // It is called by generated Marshal methods on protocol buffer messages with the message_set_wire_format option.
 func MarshalMessageSet(m map[int32]Extension) ([]byte, error) {
 	if err := encodeExtensionMap(m); err != nil {
 		return nil, err
 	}

 	// Sort extension IDs to provide a deterministic encoding.
 	// See also enc_map in encode.go.
 	ids := make([]int, 0, len(m))
 	for id := range m {
 		ids = append(ids, int(id))
 	}
 	sort.Ints(ids)

 	ms := &messageSet{Item: make([]*_MessageSet_Item, 0, len(m))}
 	for _, id := range ids {
 		e := m[int32(id)]
 		// Remove the wire type and field number varint, as well as the length varint.
 		msg := skipVarint(skipVarint(e.enc))

 		ms.Item = append(ms.Item, &_MessageSet_Item{
 			TypeId:  Int32(int32(id)),
 			Message: msg,
 		})
 	}
 	return Marshal(ms)
 }

 // UnmarshalMessageSet decodes the extension map encoded in buf in the message set wire format.
 // It is called by generated Unmarshal methods on protocol buffer messages with the message_set_wire_format option.
 func UnmarshalMessageSet(buf []byte, m map[int32]Extension) error {
 	ms := new(messageSet)
 	if err := Unmarshal(buf, ms); err != nil {
 		return err
 	}
 	for _, item := range ms.Item {
 		id := *item.TypeId
 		msg := item.Message

 		// Restore wire type and field number varint, plus length varint.
 		// Be careful to preserve duplicate items.
 		b := EncodeVarint(uint64(id)<<3 | WireBytes)
 		if ext, ok := m[id]; ok {
 			// Existing data; rip off the tag and length varint
 			// so we join the new data correctly.
 			// We can assume that ext.enc is set because we are unmarshaling.
 			o := ext.enc[len(b):]   // skip wire type and field number
 			_, n := DecodeVarint(o) // calculate length of length varint
 			o = o[n:]               // skip length varint
 			msg = append(o, msg...) // join old data and new data
 		}
 		b = append(b, EncodeVarint(uint64(len(msg)))...)
 		b = append(b, msg...)

 		m[id] = Extension{enc: b}
 	}
 	return nil
 }

 // MarshalMessageSetJSON encodes the extension map represented by m in JSON format.
 // It is called by generated MarshalJSON methods on protocol buffer messages with the message_set_wire_format option.
 func MarshalMessageSetJSON(m map[int32]Extension) ([]byte, error) {
 	var b bytes.Buffer
 	b.WriteByte('{')

 	// Process the map in key order for deterministic output.
 	ids := make([]int32, 0, len(m))
 	for id := range m {
 		ids = append(ids, id)
 	}
 	sort.Sort(int32Slice(ids)) // int32Slice defined in text.go

 	for i, id := range ids {
 		ext := m[id]
 		if i > 0 {
 			b.WriteByte(',')
 		}

 		msd, ok := messageSetMap[id]
 		if !ok {
 			// Unknown type; we can't render it, so skip it.
 			continue
 		}
 		fmt.Fprintf(&b, `"[%s]":`, msd.name)

 		x := ext.value
 		if x == nil {
 			x = reflect.New(msd.t.Elem()).Interface()
 			if err := Unmarshal(ext.enc, x.(Message)); err != nil {
 				return nil, err
 			}
 		}
 		d, err := json.Marshal(x)
 		if err != nil {
 			return nil, err
 		}
 		b.Write(d)
 	}
 	b.WriteByte('}')
 	return b.Bytes(), nil
 }

 // UnmarshalMessageSetJSON decodes the extension map encoded in buf in JSON format.
 // It is called by generated UnmarshalJSON methods on protocol buffer messages with the message_set_wire_format option.
 func UnmarshalMessageSetJSON(buf []byte, m map[int32]Extension) error {
 	// Common-case fast path.
 	if len(buf) == 0 || bytes.Equal(buf, []byte("{}")) {
 		return nil
 	}

 	// This is fairly tricky, and it's not clear that it is needed.
 	return errors.New("TODO: UnmarshalMessageSetJSON not yet implemented")
 }

 // A global registry of types that can be used in a MessageSet.

 var messageSetMap = make(map[int32]messageSetDesc)

 type messageSetDesc struct {
 	t    reflect.Type // pointer to struct
 	name string
 }

 // RegisterMessageSetType is called from the generated code.
 func RegisterMessageSetType(m Message, fieldNum int32, name string) {
 	messageSetMap[fieldNum] = messageSetDesc{
 		t:    reflect.TypeOf(m),
 		name: name,
 	}
 }
	// Go support for Protocol Buffers - Google's data interchange format
	//
	// Copyright 2010 The Go Authors. All rights reserved.
	// https://github.com/golang/protobuf
	//
	// Redistribution and use in source and binary forms, with or without
	// modification, are permitted provided that the following conditions are
	// met:
	//
	// * Redistributions of source code must retain the above copyright
	// notice, this list of conditions and the following disclaimer.
	// * Redistributions in binary form must reproduce the above
	// copyright notice, this list of conditions and the following disclaimer
	// in the documentation and/or other materials provided with the
	// distribution.
	// * Neither the name of Google Inc. nor the names of its
	// contributors may be used to endorse or promote products derived from
	// this software without specific prior written permission.
	//
	// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

	package proto

	/*
	* Support for message sets.
	*/

	import (
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"reflect"
	"sort"
	)

	// errNoMessageTypeID occurs when a protocol buffer does not have a message type ID.
	// A message type ID is required for storing a protocol buffer in a message set.
	var errNoMessageTypeID = errors.New("proto does not have a message type ID")

	// The first two types (_MessageSet_Item and messageSet)
	// model what the protocol compiler produces for the following protocol message:
	// message MessageSet {
	// repeated group Item = 1 {
	// required int32 type_id = 2;
	// required string message = 3;
	// };
	// }
	// That is the MessageSet wire format. We can't use a proto to generate these
	// because that would introduce a circular dependency between it and this package.

	type _MessageSet_Item struct {
	TypeId *int32 `protobuf:"varint,2,req,name=type_id"`
	Message []byte `protobuf:"bytes,3,req,name=message"`
	}

	type messageSet struct {
	Item []*_MessageSet_Item `protobuf:"group,1,rep"`
	XXX_unrecognized []byte
	// TODO: caching?
	}

	// Make sure messageSet is a Message.
	var _ Message = (*messageSet)(nil)

	// messageTypeIder is an interface satisfied by a protocol buffer type
	// that may be stored in a MessageSet.
	type messageTypeIder interface {
	MessageTypeId() int32
	}

	func (ms messageSet) find(pb Message) _MessageSet_Item {
	mti, ok := pb.(messageTypeIder)
	if !ok {
	return nil
	}
	id := mti.MessageTypeId()
	for _, item := range ms.Item {
	if *item.TypeId == id {
	return item
	}
	}
	return nil
	}

	func (ms *messageSet) Has(pb Message) bool {
	if ms.find(pb) != nil {
	return true
	}
	return false
	}

	func (ms *messageSet) Unmarshal(pb Message) error {
	if item := ms.find(pb); item != nil {
	return Unmarshal(item.Message, pb)
	}
	if _, ok := pb.(messageTypeIder); !ok {
	return errNoMessageTypeID
	}
	return nil // TODO: return error instead?
	}

	func (ms *messageSet) Marshal(pb Message) error {
	msg, err := Marshal(pb)
	if err != nil {
	return err
	}
	if item := ms.find(pb); item != nil {
	// reuse existing item
	item.Message = msg
	return nil
	}

	mti, ok := pb.(messageTypeIder)
	if !ok {
	return errNoMessageTypeID
	}

	mtid := mti.MessageTypeId()
	ms.Item = append(ms.Item, &_MessageSet_Item{
	TypeId: &mtid,
	Message: msg,
	})
	return nil
	}

	func (ms messageSet) Reset() { ms = messageSet{} }
	func (ms *messageSet) String() string { return CompactTextString(ms) }
	func (*messageSet) ProtoMessage() {}

	// Support for the message_set_wire_format message option.

	func skipVarint(buf []byte) []byte {
	i := 0
	for ; buf[i]&0x80 != 0; i++ {
	}
	return buf[i+1:]
	}

	// MarshalMessageSet encodes the extension map represented by m in the message set wire format.
	// It is called by generated Marshal methods on protocol buffer messages with the message_set_wire_format option.
	func MarshalMessageSet(m map[int32]Extension) ([]byte, error) {
	if err := encodeExtensionMap(m); err != nil {
	return nil, err
	}

	// Sort extension IDs to provide a deterministic encoding.
	// See also enc_map in encode.go.
	ids := make([]int, 0, len(m))
	for id := range m {
	ids = append(ids, int(id))
	}
	sort.Ints(ids)

	ms := &messageSet{Item: make([]*_MessageSet_Item, 0, len(m))}
	for _, id := range ids {
	e := m[int32(id)]
	// Remove the wire type and field number varint, as well as the length varint.
	msg := skipVarint(skipVarint(e.enc))

	ms.Item = append(ms.Item, &_MessageSet_Item{
	TypeId: Int32(int32(id)),
	Message: msg,
	})
	}
	return Marshal(ms)
	}

	// UnmarshalMessageSet decodes the extension map encoded in buf in the message set wire format.
	// It is called by generated Unmarshal methods on protocol buffer messages with the message_set_wire_format option.
	func UnmarshalMessageSet(buf []byte, m map[int32]Extension) error {
	ms := new(messageSet)
	if err := Unmarshal(buf, ms); err != nil {
	return err
	}
	for _, item := range ms.Item {
	id := *item.TypeId
	msg := item.Message

	// Restore wire type and field number varint, plus length varint.
	// Be careful to preserve duplicate items.
	b := EncodeVarint(uint64(id)<<3 \| WireBytes)
	if ext, ok := m[id]; ok {
	// Existing data; rip off the tag and length varint
	// so we join the new data correctly.
	// We can assume that ext.enc is set because we are unmarshaling.
	o := ext.enc[len(b):] // skip wire type and field number
	_, n := DecodeVarint(o) // calculate length of length varint
	o = o[n:] // skip length varint
	msg = append(o, msg...) // join old data and new data
	}
	b = append(b, EncodeVarint(uint64(len(msg)))...)
	b = append(b, msg...)

	m[id] = Extension{enc: b}
	}
	return nil
	}

	// MarshalMessageSetJSON encodes the extension map represented by m in JSON format.
	// It is called by generated MarshalJSON methods on protocol buffer messages with the message_set_wire_format option.
	func MarshalMessageSetJSON(m map[int32]Extension) ([]byte, error) {
	var b bytes.Buffer
	b.WriteByte('{')

	// Process the map in key order for deterministic output.
	ids := make([]int32, 0, len(m))
	for id := range m {
	ids = append(ids, id)
	}
	sort.Sort(int32Slice(ids)) // int32Slice defined in text.go

	for i, id := range ids {
	ext := m[id]
	if i > 0 {
	b.WriteByte(',')
	}

	msd, ok := messageSetMap[id]
	if !ok {
	// Unknown type; we can't render it, so skip it.
	continue
	}
	fmt.Fprintf(&b, `"[%s]":`, msd.name)

	x := ext.value
	if x == nil {
	x = reflect.New(msd.t.Elem()).Interface()
	if err := Unmarshal(ext.enc, x.(Message)); err != nil {
	return nil, err
	}
	}
	d, err := json.Marshal(x)
	if err != nil {
	return nil, err
	}
	b.Write(d)
	}
	b.WriteByte('}')
	return b.Bytes(), nil
	}

	// UnmarshalMessageSetJSON decodes the extension map encoded in buf in JSON format.
	// It is called by generated UnmarshalJSON methods on protocol buffer messages with the message_set_wire_format option.
	func UnmarshalMessageSetJSON(buf []byte, m map[int32]Extension) error {
	// Common-case fast path.
	if len(buf) == 0 \|\| bytes.Equal(buf, []byte("{}")) {
	return nil
	}

	// This is fairly tricky, and it's not clear that it is needed.
	return errors.New("TODO: UnmarshalMessageSetJSON not yet implemented")
	}

	// A global registry of types that can be used in a MessageSet.

	var messageSetMap = make(map[int32]messageSetDesc)

	type messageSetDesc struct {
	t reflect.Type // pointer to struct
	name string
	}

	// RegisterMessageSetType is called from the generated code.
	func RegisterMessageSetType(m Message, fieldNum int32, name string) {
	messageSetMap[fieldNum] = messageSetDesc{
	t: reflect.TypeOf(m),
	name: name,
	}
	}