// 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] }