vendor/github.com/golang/protobuf/proto/properties.go - voltctl - Gitiles

 // 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

 /*
  * Routines for encoding data into the wire format for protocol buffers.
  */

 import (
 	"fmt"
 	"log"
 	"os"
 	"reflect"
 	"sort"
 	"strconv"
 	"strings"
 	"sync"
 )

 const debug bool = false

 // Constants that identify the encoding of a value on the wire.
 const (
 	WireVarint     = 0
 	WireFixed64    = 1
 	WireBytes      = 2
 	WireStartGroup = 3
 	WireEndGroup   = 4
 	WireFixed32    = 5
 )

 // tagMap is an optimization over map[int]int for typical protocol buffer
 // use-cases. Encoded protocol buffers are often in tag order with small tag
 // numbers.
 type tagMap struct {
 	fastTags []int
 	slowTags map[int]int
 }

 // tagMapFastLimit is the upper bound on the tag number that will be stored in
 // the tagMap slice rather than its map.
 const tagMapFastLimit = 1024

 func (p *tagMap) get(t int) (int, bool) {
 	if t > 0 && t < tagMapFastLimit {
 		if t >= len(p.fastTags) {
 			return 0, false
 		}
 		fi := p.fastTags[t]
 		return fi, fi >= 0
 	}
 	fi, ok := p.slowTags[t]
 	return fi, ok
 }

 func (p *tagMap) put(t int, fi int) {
 	if t > 0 && t < tagMapFastLimit {
 		for len(p.fastTags) < t+1 {
 			p.fastTags = append(p.fastTags, -1)
 		}
 		p.fastTags[t] = fi
 		return
 	}
 	if p.slowTags == nil {
 		p.slowTags = make(map[int]int)
 	}
 	p.slowTags[t] = fi
 }

 // StructProperties represents properties for all the fields of a struct.
 // decoderTags and decoderOrigNames should only be used by the decoder.
 type StructProperties struct {
 	Prop             []*Properties  // properties for each field
 	reqCount         int            // required count
 	decoderTags      tagMap         // map from proto tag to struct field number
 	decoderOrigNames map[string]int // map from original name to struct field number
 	order            []int          // list of struct field numbers in tag order

 	// OneofTypes contains information about the oneof fields in this message.
 	// It is keyed by the original name of a field.
 	OneofTypes map[string]*OneofProperties
 }

 // OneofProperties represents information about a specific field in a oneof.
 type OneofProperties struct {
 	Type  reflect.Type // pointer to generated struct type for this oneof field
 	Field int          // struct field number of the containing oneof in the message
 	Prop  *Properties
 }

 // Implement the sorting interface so we can sort the fields in tag order, as recommended by the spec.
 // See encode.go, (*Buffer).enc_struct.

 func (sp *StructProperties) Len() int { return len(sp.order) }
 func (sp *StructProperties) Less(i, j int) bool {
 	return sp.Prop[sp.order[i]].Tag < sp.Prop[sp.order[j]].Tag
 }
 func (sp *StructProperties) Swap(i, j int) { sp.order[i], sp.order[j] = sp.order[j], sp.order[i] }

 // Properties represents the protocol-specific behavior of a single struct field.
 type Properties struct {
 	Name     string // name of the field, for error messages
 	OrigName string // original name before protocol compiler (always set)
 	JSONName string // name to use for JSON; determined by protoc
 	Wire     string
 	WireType int
 	Tag      int
 	Required bool
 	Optional bool
 	Repeated bool
 	Packed   bool   // relevant for repeated primitives only
 	Enum     string // set for enum types only
 	proto3   bool   // whether this is known to be a proto3 field
 	oneof    bool   // whether this is a oneof field

 	Default    string // default value
 	HasDefault bool   // whether an explicit default was provided

 	stype reflect.Type      // set for struct types only
 	sprop *StructProperties // set for struct types only

 	mtype      reflect.Type // set for map types only
 	MapKeyProp *Properties  // set for map types only
 	MapValProp *Properties  // set for map types only
 }

 // String formats the properties in the protobuf struct field tag style.
 func (p *Properties) String() string {
 	s := p.Wire
 	s += ","
 	s += strconv.Itoa(p.Tag)
 	if p.Required {
 		s += ",req"
 	}
 	if p.Optional {
 		s += ",opt"
 	}
 	if p.Repeated {
 		s += ",rep"
 	}
 	if p.Packed {
 		s += ",packed"
 	}
 	s += ",name=" + p.OrigName
 	if p.JSONName != p.OrigName {
 		s += ",json=" + p.JSONName
 	}
 	if p.proto3 {
 		s += ",proto3"
 	}
 	if p.oneof {
 		s += ",oneof"
 	}
 	if len(p.Enum) > 0 {
 		s += ",enum=" + p.Enum
 	}
 	if p.HasDefault {
 		s += ",def=" + p.Default
 	}
 	return s
 }

 // Parse populates p by parsing a string in the protobuf struct field tag style.
 func (p *Properties) Parse(s string) {
 	// "bytes,49,opt,name=foo,def=hello!"
 	fields := strings.Split(s, ",") // breaks def=, but handled below.
 	if len(fields) < 2 {
 		fmt.Fprintf(os.Stderr, "proto: tag has too few fields: %q\n", s)
 		return
 	}

 	p.Wire = fields[0]
 	switch p.Wire {
 	case "varint":
 		p.WireType = WireVarint
 	case "fixed32":
 		p.WireType = WireFixed32
 	case "fixed64":
 		p.WireType = WireFixed64
 	case "zigzag32":
 		p.WireType = WireVarint
 	case "zigzag64":
 		p.WireType = WireVarint
 	case "bytes", "group":
 		p.WireType = WireBytes
 		// no numeric converter for non-numeric types
 	default:
 		fmt.Fprintf(os.Stderr, "proto: tag has unknown wire type: %q\n", s)
 		return
 	}

 	var err error
 	p.Tag, err = strconv.Atoi(fields[1])
 	if err != nil {
 		return
 	}

 outer:
 	for i := 2; i < len(fields); i++ {
 		f := fields[i]
 		switch {
 		case f == "req":
 			p.Required = true
 		case f == "opt":
 			p.Optional = true
 		case f == "rep":
 			p.Repeated = true
 		case f == "packed":
 			p.Packed = true
 		case strings.HasPrefix(f, "name="):
 			p.OrigName = f[5:]
 		case strings.HasPrefix(f, "json="):
 			p.JSONName = f[5:]
 		case strings.HasPrefix(f, "enum="):
 			p.Enum = f[5:]
 		case f == "proto3":
 			p.proto3 = true
 		case f == "oneof":
 			p.oneof = true
 		case strings.HasPrefix(f, "def="):
 			p.HasDefault = true
 			p.Default = f[4:] // rest of string
 			if i+1 < len(fields) {
 				// Commas aren't escaped, and def is always last.
 				p.Default += "," + strings.Join(fields[i+1:], ",")
 				break outer
 			}
 		}
 	}
 }

 var protoMessageType = reflect.TypeOf((*Message)(nil)).Elem()

 // setFieldProps initializes the field properties for submessages and maps.
 func (p *Properties) setFieldProps(typ reflect.Type, f *reflect.StructField, lockGetProp bool) {
 	switch t1 := typ; t1.Kind() {
 	case reflect.Ptr:
 		if t1.Elem().Kind() == reflect.Struct {
 			p.stype = t1.Elem()
 		}

 	case reflect.Slice:
 		if t2 := t1.Elem(); t2.Kind() == reflect.Ptr && t2.Elem().Kind() == reflect.Struct {
 			p.stype = t2.Elem()
 		}

 	case reflect.Map:
 		p.mtype = t1
 		p.MapKeyProp = &Properties{}
 		p.MapKeyProp.init(reflect.PtrTo(p.mtype.Key()), "Key", f.Tag.Get("protobuf_key"), nil, lockGetProp)
 		p.MapValProp = &Properties{}
 		vtype := p.mtype.Elem()
 		if vtype.Kind() != reflect.Ptr && vtype.Kind() != reflect.Slice {
 			// The value type is not a message (*T) or bytes ([]byte),
 			// so we need encoders for the pointer to this type.
 			vtype = reflect.PtrTo(vtype)
 		}
 		p.MapValProp.init(vtype, "Value", f.Tag.Get("protobuf_val"), nil, lockGetProp)
 	}

 	if p.stype != nil {
 		if lockGetProp {
 			p.sprop = GetProperties(p.stype)
 		} else {
 			p.sprop = getPropertiesLocked(p.stype)
 		}
 	}
 }

 var (
 	marshalerType = reflect.TypeOf((*Marshaler)(nil)).Elem()
 )

 // Init populates the properties from a protocol buffer struct tag.
 func (p *Properties) Init(typ reflect.Type, name, tag string, f *reflect.StructField) {
 	p.init(typ, name, tag, f, true)
 }

 func (p *Properties) init(typ reflect.Type, name, tag string, f *reflect.StructField, lockGetProp bool) {
 	// "bytes,49,opt,def=hello!"
 	p.Name = name
 	p.OrigName = name
 	if tag == "" {
 		return
 	}
 	p.Parse(tag)
 	p.setFieldProps(typ, f, lockGetProp)
 }

 var (
 	propertiesMu  sync.RWMutex
 	propertiesMap = make(map[reflect.Type]*StructProperties)
 )

 // GetProperties returns the list of properties for the type represented by t.
 // t must represent a generated struct type of a protocol message.
 func GetProperties(t reflect.Type) *StructProperties {
 	if t.Kind() != reflect.Struct {
 		panic("proto: type must have kind struct")
 	}

 	// Most calls to GetProperties in a long-running program will be
 	// retrieving details for types we have seen before.
 	propertiesMu.RLock()
 	sprop, ok := propertiesMap[t]
 	propertiesMu.RUnlock()
 	if ok {
 		return sprop
 	}

 	propertiesMu.Lock()
 	sprop = getPropertiesLocked(t)
 	propertiesMu.Unlock()
 	return sprop
 }

 type (
 	oneofFuncsIface interface {
 		XXX_OneofFuncs() (func(Message, *Buffer) error, func(Message, int, int, *Buffer) (bool, error), func(Message) int, []interface{})
 	}
 	oneofWrappersIface interface {
 		XXX_OneofWrappers() []interface{}
 	}
 )

 // getPropertiesLocked requires that propertiesMu is held.
 func getPropertiesLocked(t reflect.Type) *StructProperties {
 	if prop, ok := propertiesMap[t]; ok {
 		return prop
 	}

 	prop := new(StructProperties)
 	// in case of recursive protos, fill this in now.
 	propertiesMap[t] = prop

 	// build properties
 	prop.Prop = make([]*Properties, t.NumField())
 	prop.order = make([]int, t.NumField())

 	for i := 0; i < t.NumField(); i++ {
 		f := t.Field(i)
 		p := new(Properties)
 		name := f.Name
 		p.init(f.Type, name, f.Tag.Get("protobuf"), &f, false)

 		oneof := f.Tag.Get("protobuf_oneof") // special case
 		if oneof != "" {
 			// Oneof fields don't use the traditional protobuf tag.
 			p.OrigName = oneof
 		}
 		prop.Prop[i] = p
 		prop.order[i] = i
 		if debug {
 			print(i, " ", f.Name, " ", t.String(), " ")
 			if p.Tag > 0 {
 				print(p.String())
 			}
 			print("\n")
 		}
 	}

 	// Re-order prop.order.
 	sort.Sort(prop)

 	var oots []interface{}
 	switch m := reflect.Zero(reflect.PtrTo(t)).Interface().(type) {
 	case oneofFuncsIface:
 		_, _, _, oots = m.XXX_OneofFuncs()
 	case oneofWrappersIface:
 		oots = m.XXX_OneofWrappers()
 	}
 	if len(oots) > 0 {
 		// Interpret oneof metadata.
 		prop.OneofTypes = make(map[string]*OneofProperties)
 		for _, oot := range oots {
 			oop := &OneofProperties{
 				Type: reflect.ValueOf(oot).Type(), // *T
 				Prop: new(Properties),
 			}
 			sft := oop.Type.Elem().Field(0)
 			oop.Prop.Name = sft.Name
 			oop.Prop.Parse(sft.Tag.Get("protobuf"))
 			// There will be exactly one interface field that
 			// this new value is assignable to.
 			for i := 0; i < t.NumField(); i++ {
 				f := t.Field(i)
 				if f.Type.Kind() != reflect.Interface {
 					continue
 				}
 				if !oop.Type.AssignableTo(f.Type) {
 					continue
 				}
 				oop.Field = i
 				break
 			}
 			prop.OneofTypes[oop.Prop.OrigName] = oop
 		}
 	}

 	// build required counts
 	// build tags
 	reqCount := 0
 	prop.decoderOrigNames = make(map[string]int)
 	for i, p := range prop.Prop {
 		if strings.HasPrefix(p.Name, "XXX_") {
 			// Internal fields should not appear in tags/origNames maps.
 			// They are handled specially when encoding and decoding.
 			continue
 		}
 		if p.Required {
 			reqCount++
 		}
 		prop.decoderTags.put(p.Tag, i)
 		prop.decoderOrigNames[p.OrigName] = i
 	}
 	prop.reqCount = reqCount

 	return prop
 }

 // A global registry of enum types.
 // The generated code will register the generated maps by calling RegisterEnum.

 var enumValueMaps = make(map[string]map[string]int32)

 // RegisterEnum is called from the generated code to install the enum descriptor
 // maps into the global table to aid parsing text format protocol buffers.
 func RegisterEnum(typeName string, unusedNameMap map[int32]string, valueMap map[string]int32) {
 	if _, ok := enumValueMaps[typeName]; ok {
 		panic("proto: duplicate enum registered: " + typeName)
 	}
 	enumValueMaps[typeName] = valueMap
 }

 // EnumValueMap returns the mapping from names to integers of the
 // enum type enumType, or a nil if not found.
 func EnumValueMap(enumType string) map[string]int32 {
 	return enumValueMaps[enumType]
 }

 // A registry of all linked message types.
 // The string is a fully-qualified proto name ("pkg.Message").
 var (
 	protoTypedNils = make(map[string]Message)      // a map from proto names to typed nil pointers
 	protoMapTypes  = make(map[string]reflect.Type) // a map from proto names to map types
 	revProtoTypes  = make(map[reflect.Type]string)
 )

 // RegisterType is called from generated code and maps from the fully qualified
 // proto name to the type (pointer to struct) of the protocol buffer.
 func RegisterType(x Message, name string) {
 	if _, ok := protoTypedNils[name]; ok {
 		// TODO: Some day, make this a panic.
 		log.Printf("proto: duplicate proto type registered: %s", name)
 		return
 	}
 	t := reflect.TypeOf(x)
 	if v := reflect.ValueOf(x); v.Kind() == reflect.Ptr && v.Pointer() == 0 {
 		// Generated code always calls RegisterType with nil x.
 		// This check is just for extra safety.
 		protoTypedNils[name] = x
 	} else {
 		protoTypedNils[name] = reflect.Zero(t).Interface().(Message)
 	}
 	revProtoTypes[t] = name
 }

 // RegisterMapType is called from generated code and maps from the fully qualified
 // proto name to the native map type of the proto map definition.
 func RegisterMapType(x interface{}, name string) {
 	if reflect.TypeOf(x).Kind() != reflect.Map {
 		panic(fmt.Sprintf("RegisterMapType(%T, %q); want map", x, name))
 	}
 	if _, ok := protoMapTypes[name]; ok {
 		log.Printf("proto: duplicate proto type registered: %s", name)
 		return
 	}
 	t := reflect.TypeOf(x)
 	protoMapTypes[name] = t
 	revProtoTypes[t] = name
 }

 // MessageName returns the fully-qualified proto name for the given message type.
 func MessageName(x Message) string {
 	type xname interface {
 		XXX_MessageName() string
 	}
 	if m, ok := x.(xname); ok {
 		return m.XXX_MessageName()
 	}
 	return revProtoTypes[reflect.TypeOf(x)]
 }

 // MessageType returns the message type (pointer to struct) for a named message.
 // The type is not guaranteed to implement proto.Message if the name refers to a
 // map entry.
 func MessageType(name string) reflect.Type {
 	if t, ok := protoTypedNils[name]; ok {
 		return reflect.TypeOf(t)
 	}
 	return protoMapTypes[name]
 }

 // A registry of all linked proto files.
 var (
 	protoFiles = make(map[string][]byte) // file name => fileDescriptor
 )

 // RegisterFile is called from generated code and maps from the
 // full file name of a .proto file to its compressed FileDescriptorProto.
 func RegisterFile(filename string, fileDescriptor []byte) {
 	protoFiles[filename] = fileDescriptor
 }

 // FileDescriptor returns the compressed FileDescriptorProto for a .proto file.
 func FileDescriptor(filename string) []byte { return protoFiles[filename] }
	// 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

	/*
	* Routines for encoding data into the wire format for protocol buffers.
	*/

	import (
	"fmt"
	"log"
	"os"
	"reflect"
	"sort"
	"strconv"
	"strings"
	"sync"
	)

	const debug bool = false

	// Constants that identify the encoding of a value on the wire.
	const (
	WireVarint = 0
	WireFixed64 = 1
	WireBytes = 2
	WireStartGroup = 3
	WireEndGroup = 4
	WireFixed32 = 5
	)

	// tagMap is an optimization over map[int]int for typical protocol buffer
	// use-cases. Encoded protocol buffers are often in tag order with small tag
	// numbers.
	type tagMap struct {
	fastTags []int
	slowTags map[int]int
	}

	// tagMapFastLimit is the upper bound on the tag number that will be stored in
	// the tagMap slice rather than its map.
	const tagMapFastLimit = 1024

	func (p *tagMap) get(t int) (int, bool) {
	if t > 0 && t < tagMapFastLimit {
	if t >= len(p.fastTags) {
	return 0, false
	}
	fi := p.fastTags[t]
	return fi, fi >= 0
	}
	fi, ok := p.slowTags[t]
	return fi, ok
	}

	func (p *tagMap) put(t int, fi int) {
	if t > 0 && t < tagMapFastLimit {
	for len(p.fastTags) < t+1 {
	p.fastTags = append(p.fastTags, -1)
	}
	p.fastTags[t] = fi
	return
	}
	if p.slowTags == nil {
	p.slowTags = make(map[int]int)
	}
	p.slowTags[t] = fi
	}

	// StructProperties represents properties for all the fields of a struct.
	// decoderTags and decoderOrigNames should only be used by the decoder.
	type StructProperties struct {
	Prop []*Properties // properties for each field
	reqCount int // required count
	decoderTags tagMap // map from proto tag to struct field number
	decoderOrigNames map[string]int // map from original name to struct field number
	order []int // list of struct field numbers in tag order

	// OneofTypes contains information about the oneof fields in this message.
	// It is keyed by the original name of a field.
	OneofTypes map[string]*OneofProperties
	}

	// OneofProperties represents information about a specific field in a oneof.
	type OneofProperties struct {
	Type reflect.Type // pointer to generated struct type for this oneof field
	Field int // struct field number of the containing oneof in the message
	Prop *Properties
	}

	// Implement the sorting interface so we can sort the fields in tag order, as recommended by the spec.
	// See encode.go, (*Buffer).enc_struct.

	func (sp *StructProperties) Len() int { return len(sp.order) }
	func (sp *StructProperties) Less(i, j int) bool {
	return sp.Prop[sp.order[i]].Tag < sp.Prop[sp.order[j]].Tag
	}
	func (sp *StructProperties) Swap(i, j int) { sp.order[i], sp.order[j] = sp.order[j], sp.order[i] }

	// Properties represents the protocol-specific behavior of a single struct field.
	type Properties struct {
	Name string // name of the field, for error messages
	OrigName string // original name before protocol compiler (always set)
	JSONName string // name to use for JSON; determined by protoc
	Wire string
	WireType int
	Tag int
	Required bool
	Optional bool
	Repeated bool
	Packed bool // relevant for repeated primitives only
	Enum string // set for enum types only
	proto3 bool // whether this is known to be a proto3 field
	oneof bool // whether this is a oneof field

	Default string // default value
	HasDefault bool // whether an explicit default was provided

	stype reflect.Type // set for struct types only
	sprop *StructProperties // set for struct types only

	mtype reflect.Type // set for map types only
	MapKeyProp *Properties // set for map types only
	MapValProp *Properties // set for map types only
	}

	// String formats the properties in the protobuf struct field tag style.
	func (p *Properties) String() string {
	s := p.Wire
	s += ","
	s += strconv.Itoa(p.Tag)
	if p.Required {
	s += ",req"
	}
	if p.Optional {
	s += ",opt"
	}
	if p.Repeated {
	s += ",rep"
	}
	if p.Packed {
	s += ",packed"
	}
	s += ",name=" + p.OrigName
	if p.JSONName != p.OrigName {
	s += ",json=" + p.JSONName
	}
	if p.proto3 {
	s += ",proto3"
	}
	if p.oneof {
	s += ",oneof"
	}
	if len(p.Enum) > 0 {
	s += ",enum=" + p.Enum
	}
	if p.HasDefault {
	s += ",def=" + p.Default
	}
	return s
	}

	// Parse populates p by parsing a string in the protobuf struct field tag style.
	func (p *Properties) Parse(s string) {
	// "bytes,49,opt,name=foo,def=hello!"
	fields := strings.Split(s, ",") // breaks def=, but handled below.
	if len(fields) < 2 {
	fmt.Fprintf(os.Stderr, "proto: tag has too few fields: %q\n", s)
	return
	}

	p.Wire = fields[0]
	switch p.Wire {
	case "varint":
	p.WireType = WireVarint
	case "fixed32":
	p.WireType = WireFixed32
	case "fixed64":
	p.WireType = WireFixed64
	case "zigzag32":
	p.WireType = WireVarint
	case "zigzag64":
	p.WireType = WireVarint
	case "bytes", "group":
	p.WireType = WireBytes
	// no numeric converter for non-numeric types
	default:
	fmt.Fprintf(os.Stderr, "proto: tag has unknown wire type: %q\n", s)
	return
	}

	var err error
	p.Tag, err = strconv.Atoi(fields[1])
	if err != nil {
	return
	}

	outer:
	for i := 2; i < len(fields); i++ {
	f := fields[i]
	switch {
	case f == "req":
	p.Required = true
	case f == "opt":
	p.Optional = true
	case f == "rep":
	p.Repeated = true
	case f == "packed":
	p.Packed = true
	case strings.HasPrefix(f, "name="):
	p.OrigName = f[5:]
	case strings.HasPrefix(f, "json="):
	p.JSONName = f[5:]
	case strings.HasPrefix(f, "enum="):
	p.Enum = f[5:]
	case f == "proto3":
	p.proto3 = true
	case f == "oneof":
	p.oneof = true
	case strings.HasPrefix(f, "def="):
	p.HasDefault = true
	p.Default = f[4:] // rest of string
	if i+1 < len(fields) {
	// Commas aren't escaped, and def is always last.
	p.Default += "," + strings.Join(fields[i+1:], ",")
	break outer
	}
	}
	}
	}

	var protoMessageType = reflect.TypeOf((*Message)(nil)).Elem()

	// setFieldProps initializes the field properties for submessages and maps.
	func (p Properties) setFieldProps(typ reflect.Type, f reflect.StructField, lockGetProp bool) {
	switch t1 := typ; t1.Kind() {
	case reflect.Ptr:
	if t1.Elem().Kind() == reflect.Struct {
	p.stype = t1.Elem()
	}

	case reflect.Slice:
	if t2 := t1.Elem(); t2.Kind() == reflect.Ptr && t2.Elem().Kind() == reflect.Struct {
	p.stype = t2.Elem()
	}

	case reflect.Map:
	p.mtype = t1
	p.MapKeyProp = &Properties{}
	p.MapKeyProp.init(reflect.PtrTo(p.mtype.Key()), "Key", f.Tag.Get("protobuf_key"), nil, lockGetProp)
	p.MapValProp = &Properties{}
	vtype := p.mtype.Elem()
	if vtype.Kind() != reflect.Ptr && vtype.Kind() != reflect.Slice {
	// The value type is not a message (*T) or bytes ([]byte),
	// so we need encoders for the pointer to this type.
	vtype = reflect.PtrTo(vtype)
	}
	p.MapValProp.init(vtype, "Value", f.Tag.Get("protobuf_val"), nil, lockGetProp)
	}

	if p.stype != nil {
	if lockGetProp {
	p.sprop = GetProperties(p.stype)
	} else {
	p.sprop = getPropertiesLocked(p.stype)
	}
	}
	}

	var (
	marshalerType = reflect.TypeOf((*Marshaler)(nil)).Elem()
	)

	// Init populates the properties from a protocol buffer struct tag.
	func (p Properties) Init(typ reflect.Type, name, tag string, f reflect.StructField) {
	p.init(typ, name, tag, f, true)
	}

	func (p Properties) init(typ reflect.Type, name, tag string, f reflect.StructField, lockGetProp bool) {
	// "bytes,49,opt,def=hello!"
	p.Name = name
	p.OrigName = name
	if tag == "" {
	return
	}
	p.Parse(tag)
	p.setFieldProps(typ, f, lockGetProp)
	}

	var (
	propertiesMu sync.RWMutex
	propertiesMap = make(map[reflect.Type]*StructProperties)
	)

	// GetProperties returns the list of properties for the type represented by t.
	// t must represent a generated struct type of a protocol message.
	func GetProperties(t reflect.Type) *StructProperties {
	if t.Kind() != reflect.Struct {
	panic("proto: type must have kind struct")
	}

	// Most calls to GetProperties in a long-running program will be
	// retrieving details for types we have seen before.
	propertiesMu.RLock()
	sprop, ok := propertiesMap[t]
	propertiesMu.RUnlock()
	if ok {
	return sprop
	}

	propertiesMu.Lock()
	sprop = getPropertiesLocked(t)
	propertiesMu.Unlock()
	return sprop
	}

	type (
	oneofFuncsIface interface {
	XXX_OneofFuncs() (func(Message, Buffer) error, func(Message, int, int, Buffer) (bool, error), func(Message) int, []interface{})
	}
	oneofWrappersIface interface {
	XXX_OneofWrappers() []interface{}
	}
	)

	// getPropertiesLocked requires that propertiesMu is held.
	func getPropertiesLocked(t reflect.Type) *StructProperties {
	if prop, ok := propertiesMap[t]; ok {
	return prop
	}

	prop := new(StructProperties)
	// in case of recursive protos, fill this in now.
	propertiesMap[t] = prop

	// build properties
	prop.Prop = make([]*Properties, t.NumField())
	prop.order = make([]int, t.NumField())

	for i := 0; i < t.NumField(); i++ {
	f := t.Field(i)
	p := new(Properties)
	name := f.Name
	p.init(f.Type, name, f.Tag.Get("protobuf"), &f, false)

	oneof := f.Tag.Get("protobuf_oneof") // special case
	if oneof != "" {
	// Oneof fields don't use the traditional protobuf tag.
	p.OrigName = oneof
	}
	prop.Prop[i] = p
	prop.order[i] = i
	if debug {
	print(i, " ", f.Name, " ", t.String(), " ")
	if p.Tag > 0 {
	print(p.String())
	}
	print("\n")
	}
	}

	// Re-order prop.order.
	sort.Sort(prop)

	var oots []interface{}
	switch m := reflect.Zero(reflect.PtrTo(t)).Interface().(type) {
	case oneofFuncsIface:
	_, _, _, oots = m.XXX_OneofFuncs()
	case oneofWrappersIface:
	oots = m.XXX_OneofWrappers()
	}
	if len(oots) > 0 {
	// Interpret oneof metadata.
	prop.OneofTypes = make(map[string]*OneofProperties)
	for _, oot := range oots {
	oop := &OneofProperties{
	Type: reflect.ValueOf(oot).Type(), // *T
	Prop: new(Properties),
	}
	sft := oop.Type.Elem().Field(0)
	oop.Prop.Name = sft.Name
	oop.Prop.Parse(sft.Tag.Get("protobuf"))
	// There will be exactly one interface field that
	// this new value is assignable to.
	for i := 0; i < t.NumField(); i++ {
	f := t.Field(i)
	if f.Type.Kind() != reflect.Interface {
	continue
	}
	if !oop.Type.AssignableTo(f.Type) {
	continue
	}
	oop.Field = i
	break
	}
	prop.OneofTypes[oop.Prop.OrigName] = oop
	}
	}

	// build required counts
	// build tags
	reqCount := 0
	prop.decoderOrigNames = make(map[string]int)
	for i, p := range prop.Prop {
	if strings.HasPrefix(p.Name, "XXX_") {
	// Internal fields should not appear in tags/origNames maps.
	// They are handled specially when encoding and decoding.
	continue
	}
	if p.Required {
	reqCount++
	}
	prop.decoderTags.put(p.Tag, i)
	prop.decoderOrigNames[p.OrigName] = i
	}
	prop.reqCount = reqCount

	return prop
	}

	// A global registry of enum types.
	// The generated code will register the generated maps by calling RegisterEnum.

	var enumValueMaps = make(map[string]map[string]int32)

	// RegisterEnum is called from the generated code to install the enum descriptor
	// maps into the global table to aid parsing text format protocol buffers.
	func RegisterEnum(typeName string, unusedNameMap map[int32]string, valueMap map[string]int32) {
	if _, ok := enumValueMaps[typeName]; ok {
	panic("proto: duplicate enum registered: " + typeName)
	}
	enumValueMaps[typeName] = valueMap
	}

	// EnumValueMap returns the mapping from names to integers of the
	// enum type enumType, or a nil if not found.
	func EnumValueMap(enumType string) map[string]int32 {
	return enumValueMaps[enumType]
	}

	// A registry of all linked message types.
	// The string is a fully-qualified proto name ("pkg.Message").
	var (
	protoTypedNils = make(map[string]Message) // a map from proto names to typed nil pointers
	protoMapTypes = make(map[string]reflect.Type) // a map from proto names to map types
	revProtoTypes = make(map[reflect.Type]string)
	)

	// RegisterType is called from generated code and maps from the fully qualified
	// proto name to the type (pointer to struct) of the protocol buffer.
	func RegisterType(x Message, name string) {
	if _, ok := protoTypedNils[name]; ok {
	// TODO: Some day, make this a panic.
	log.Printf("proto: duplicate proto type registered: %s", name)
	return
	}
	t := reflect.TypeOf(x)
	if v := reflect.ValueOf(x); v.Kind() == reflect.Ptr && v.Pointer() == 0 {
	// Generated code always calls RegisterType with nil x.
	// This check is just for extra safety.
	protoTypedNils[name] = x
	} else {
	protoTypedNils[name] = reflect.Zero(t).Interface().(Message)
	}
	revProtoTypes[t] = name
	}

	// RegisterMapType is called from generated code and maps from the fully qualified
	// proto name to the native map type of the proto map definition.
	func RegisterMapType(x interface{}, name string) {
	if reflect.TypeOf(x).Kind() != reflect.Map {
	panic(fmt.Sprintf("RegisterMapType(%T, %q); want map", x, name))
	}
	if _, ok := protoMapTypes[name]; ok {
	log.Printf("proto: duplicate proto type registered: %s", name)
	return
	}
	t := reflect.TypeOf(x)
	protoMapTypes[name] = t
	revProtoTypes[t] = name
	}

	// MessageName returns the fully-qualified proto name for the given message type.
	func MessageName(x Message) string {
	type xname interface {
	XXX_MessageName() string
	}
	if m, ok := x.(xname); ok {
	return m.XXX_MessageName()
	}
	return revProtoTypes[reflect.TypeOf(x)]
	}

	// MessageType returns the message type (pointer to struct) for a named message.
	// The type is not guaranteed to implement proto.Message if the name refers to a
	// map entry.
	func MessageType(name string) reflect.Type {
	if t, ok := protoTypedNils[name]; ok {
	return reflect.TypeOf(t)
	}
	return protoMapTypes[name]
	}

	// A registry of all linked proto files.
	var (
	protoFiles = make(map[string][]byte) // file name => fileDescriptor
	)

	// RegisterFile is called from generated code and maps from the
	// full file name of a .proto file to its compressed FileDescriptorProto.
	func RegisterFile(filename string, fileDescriptor []byte) {
	protoFiles[filename] = fileDescriptor
	}

	// FileDescriptor returns the compressed FileDescriptorProto for a .proto file.
	func FileDescriptor(filename string) []byte { return protoFiles[filename] }