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// 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
// Functions for writing the text protocol buffer format.
import (
"bufio"
"bytes"
"encoding"
"errors"
"fmt"
"io"
"log"
"math"
"reflect"
"sort"
"strings"
)
var (
newline = []byte("\n")
spaces = []byte(" ")
endBraceNewline = []byte("}\n")
backslashN = []byte{'\\', 'n'}
backslashR = []byte{'\\', 'r'}
backslashT = []byte{'\\', 't'}
backslashDQ = []byte{'\\', '"'}
backslashBS = []byte{'\\', '\\'}
posInf = []byte("inf")
negInf = []byte("-inf")
nan = []byte("nan")
)
type writer interface {
io.Writer
WriteByte(byte) error
}
// textWriter is an io.Writer that tracks its indentation level.
type textWriter struct {
ind int
complete bool // if the current position is a complete line
compact bool // whether to write out as a one-liner
w writer
}
func (w *textWriter) WriteString(s string) (n int, err error) {
if !strings.Contains(s, "\n") {
if !w.compact && w.complete {
w.writeIndent()
}
w.complete = false
return io.WriteString(w.w, s)
}
// WriteString is typically called without newlines, so this
// codepath and its copy are rare. We copy to avoid
// duplicating all of Write's logic here.
return w.Write([]byte(s))
}
func (w *textWriter) Write(p []byte) (n int, err error) {
newlines := bytes.Count(p, newline)
if newlines == 0 {
if !w.compact && w.complete {
w.writeIndent()
}
n, err = w.w.Write(p)
w.complete = false
return n, err
}
frags := bytes.SplitN(p, newline, newlines+1)
if w.compact {
for i, frag := range frags {
if i > 0 {
if err := w.w.WriteByte(' '); err != nil {
return n, err
}
n++
}
nn, err := w.w.Write(frag)
n += nn
if err != nil {
return n, err
}
}
return n, nil
}
for i, frag := range frags {
if w.complete {
w.writeIndent()
}
nn, err := w.w.Write(frag)
n += nn
if err != nil {
return n, err
}
if i+1 < len(frags) {
if err := w.w.WriteByte('\n'); err != nil {
return n, err
}
n++
}
}
w.complete = len(frags[len(frags)-1]) == 0
return n, nil
}
func (w *textWriter) WriteByte(c byte) error {
if w.compact && c == '\n' {
c = ' '
}
if !w.compact && w.complete {
w.writeIndent()
}
err := w.w.WriteByte(c)
w.complete = c == '\n'
return err
}
func (w *textWriter) indent() { w.ind++ }
func (w *textWriter) unindent() {
if w.ind == 0 {
log.Print("proto: textWriter unindented too far")
return
}
w.ind--
}
func writeName(w *textWriter, props *Properties) error {
if _, err := w.WriteString(props.OrigName); err != nil {
return err
}
if props.Wire != "group" {
return w.WriteByte(':')
}
return nil
}
func requiresQuotes(u string) bool {
// When type URL contains any characters except [0-9A-Za-z./\-]*, it must be quoted.
for _, ch := range u {
switch {
case ch == '.' || ch == '/' || ch == '_':
continue
case '0' <= ch && ch <= '9':
continue
case 'A' <= ch && ch <= 'Z':
continue
case 'a' <= ch && ch <= 'z':
continue
default:
return true
}
}
return false
}
// isAny reports whether sv is a google.protobuf.Any message
func isAny(sv reflect.Value) bool {
type wkt interface {
XXX_WellKnownType() string
}
t, ok := sv.Addr().Interface().(wkt)
return ok && t.XXX_WellKnownType() == "Any"
}
// writeProto3Any writes an expanded google.protobuf.Any message.
//
// It returns (false, nil) if sv value can't be unmarshaled (e.g. because
// required messages are not linked in).
//
// It returns (true, error) when sv was written in expanded format or an error
// was encountered.
func (tm *TextMarshaler) writeProto3Any(w *textWriter, sv reflect.Value) (bool, error) {
turl := sv.FieldByName("TypeUrl")
val := sv.FieldByName("Value")
if !turl.IsValid() || !val.IsValid() {
return true, errors.New("proto: invalid google.protobuf.Any message")
}
b, ok := val.Interface().([]byte)
if !ok {
return true, errors.New("proto: invalid google.protobuf.Any message")
}
parts := strings.Split(turl.String(), "/")
mt := MessageType(parts[len(parts)-1])
if mt == nil {
return false, nil
}
m := reflect.New(mt.Elem())
if err := Unmarshal(b, m.Interface().(Message)); err != nil {
return false, nil
}
w.Write([]byte("["))
u := turl.String()
if requiresQuotes(u) {
writeString(w, u)
} else {
w.Write([]byte(u))
}
if w.compact {
w.Write([]byte("]:<"))
} else {
w.Write([]byte("]: <\n"))
w.ind++
}
if err := tm.writeStruct(w, m.Elem()); err != nil {
return true, err
}
if w.compact {
w.Write([]byte("> "))
} else {
w.ind--
w.Write([]byte(">\n"))
}
return true, nil
}
func (tm *TextMarshaler) writeStruct(w *textWriter, sv reflect.Value) error {
if tm.ExpandAny && isAny(sv) {
if canExpand, err := tm.writeProto3Any(w, sv); canExpand {
return err
}
}
st := sv.Type()
sprops := GetProperties(st)
for i := 0; i < sv.NumField(); i++ {
fv := sv.Field(i)
props := sprops.Prop[i]
name := st.Field(i).Name
if name == "XXX_NoUnkeyedLiteral" {
continue
}
if strings.HasPrefix(name, "XXX_") {
// There are two XXX_ fields:
// XXX_unrecognized []byte
// XXX_extensions map[int32]proto.Extension
// The first is handled here;
// the second is handled at the bottom of this function.
if name == "XXX_unrecognized" && !fv.IsNil() {
if err := writeUnknownStruct(w, fv.Interface().([]byte)); err != nil {
return err
}
}
continue
}
if fv.Kind() == reflect.Ptr && fv.IsNil() {
// Field not filled in. This could be an optional field or
// a required field that wasn't filled in. Either way, there
// isn't anything we can show for it.
continue
}
if fv.Kind() == reflect.Slice && fv.IsNil() {
// Repeated field that is empty, or a bytes field that is unused.
continue
}
if props.Repeated && fv.Kind() == reflect.Slice {
// Repeated field.
for j := 0; j < fv.Len(); j++ {
if err := writeName(w, props); err != nil {
return err
}
if !w.compact {
if err := w.WriteByte(' '); err != nil {
return err
}
}
v := fv.Index(j)
if v.Kind() == reflect.Ptr && v.IsNil() {
// A nil message in a repeated field is not valid,
// but we can handle that more gracefully than panicking.
if _, err := w.Write([]byte("<nil>\n")); err != nil {
return err
}
continue
}
if err := tm.writeAny(w, v, props); err != nil {
return err
}
if err := w.WriteByte('\n'); err != nil {
return err
}
}
continue
}
if fv.Kind() == reflect.Map {
// Map fields are rendered as a repeated struct with key/value fields.
keys := fv.MapKeys()
sort.Sort(mapKeys(keys))
for _, key := range keys {
val := fv.MapIndex(key)
if err := writeName(w, props); err != nil {
return err
}
if !w.compact {
if err := w.WriteByte(' '); err != nil {
return err
}
}
// open struct
if err := w.WriteByte('<'); err != nil {
return err
}
if !w.compact {
if err := w.WriteByte('\n'); err != nil {
return err
}
}
w.indent()
// key
if _, err := w.WriteString("key:"); err != nil {
return err
}
if !w.compact {
if err := w.WriteByte(' '); err != nil {
return err
}
}
if err := tm.writeAny(w, key, props.MapKeyProp); err != nil {
return err
}
if err := w.WriteByte('\n'); err != nil {
return err
}
// nil values aren't legal, but we can avoid panicking because of them.
if val.Kind() != reflect.Ptr || !val.IsNil() {
// value
if _, err := w.WriteString("value:"); err != nil {
return err
}
if !w.compact {
if err := w.WriteByte(' '); err != nil {
return err
}
}
if err := tm.writeAny(w, val, props.MapValProp); err != nil {
return err
}
if err := w.WriteByte('\n'); err != nil {
return err
}
}
// close struct
w.unindent()
if err := w.WriteByte('>'); err != nil {
return err
}
if err := w.WriteByte('\n'); err != nil {
return err
}
}
continue
}
if props.proto3 && fv.Kind() == reflect.Slice && fv.Len() == 0 {
// empty bytes field
continue
}
if fv.Kind() != reflect.Ptr && fv.Kind() != reflect.Slice {
// proto3 non-repeated scalar field; skip if zero value
if isProto3Zero(fv) {
continue
}
}
if fv.Kind() == reflect.Interface {
// Check if it is a oneof.
if st.Field(i).Tag.Get("protobuf_oneof") != "" {
// fv is nil, or holds a pointer to generated struct.
// That generated struct has exactly one field,
// which has a protobuf struct tag.
if fv.IsNil() {
continue
}
inner := fv.Elem().Elem() // interface -> *T -> T
tag := inner.Type().Field(0).Tag.Get("protobuf")
props = new(Properties) // Overwrite the outer props var, but not its pointee.
props.Parse(tag)
// Write the value in the oneof, not the oneof itself.
fv = inner.Field(0)
// Special case to cope with malformed messages gracefully:
// If the value in the oneof is a nil pointer, don't panic
// in writeAny.
if fv.Kind() == reflect.Ptr && fv.IsNil() {
// Use errors.New so writeAny won't render quotes.
msg := errors.New("/* nil */")
fv = reflect.ValueOf(&msg).Elem()
}
}
}
if err := writeName(w, props); err != nil {
return err
}
if !w.compact {
if err := w.WriteByte(' '); err != nil {
return err
}
}
// Enums have a String method, so writeAny will work fine.
if err := tm.writeAny(w, fv, props); err != nil {
return err
}
if err := w.WriteByte('\n'); err != nil {
return err
}
}
// Extensions (the XXX_extensions field).
pv := sv.Addr()
if _, err := extendable(pv.Interface()); err == nil {
if err := tm.writeExtensions(w, pv); err != nil {
return err
}
}
return nil
}
// writeAny writes an arbitrary field.
func (tm *TextMarshaler) writeAny(w *textWriter, v reflect.Value, props *Properties) error {
v = reflect.Indirect(v)
// Floats have special cases.
if v.Kind() == reflect.Float32 || v.Kind() == reflect.Float64 {
x := v.Float()
var b []byte
switch {
case math.IsInf(x, 1):
b = posInf
case math.IsInf(x, -1):
b = negInf
case math.IsNaN(x):
b = nan
}
if b != nil {
_, err := w.Write(b)
return err
}
// Other values are handled below.
}
// We don't attempt to serialise every possible value type; only those
// that can occur in protocol buffers.
switch v.Kind() {
case reflect.Slice:
// Should only be a []byte; repeated fields are handled in writeStruct.
if err := writeString(w, string(v.Bytes())); err != nil {
return err
}
case reflect.String:
if err := writeString(w, v.String()); err != nil {
return err
}
case reflect.Struct:
// Required/optional group/message.
var bra, ket byte = '<', '>'
if props != nil && props.Wire == "group" {
bra, ket = '{', '}'
}
if err := w.WriteByte(bra); err != nil {
return err
}
if !w.compact {
if err := w.WriteByte('\n'); err != nil {
return err
}
}
w.indent()
if v.CanAddr() {
// Calling v.Interface on a struct causes the reflect package to
// copy the entire struct. This is racy with the new Marshaler
// since we atomically update the XXX_sizecache.
//
// Thus, we retrieve a pointer to the struct if possible to avoid
// a race since v.Interface on the pointer doesn't copy the struct.
//
// If v is not addressable, then we are not worried about a race
// since it implies that the binary Marshaler cannot possibly be
// mutating this value.
v = v.Addr()
}
if etm, ok := v.Interface().(encoding.TextMarshaler); ok {
text, err := etm.MarshalText()
if err != nil {
return err
}
if _, err = w.Write(text); err != nil {
return err
}
} else {
if v.Kind() == reflect.Ptr {
v = v.Elem()
}
if err := tm.writeStruct(w, v); err != nil {
return err
}
}
w.unindent()
if err := w.WriteByte(ket); err != nil {
return err
}
default:
_, err := fmt.Fprint(w, v.Interface())
return err
}
return nil
}
// equivalent to C's isprint.
func isprint(c byte) bool {
return c >= 0x20 && c < 0x7f
}
// writeString writes a string in the protocol buffer text format.
// It is similar to strconv.Quote except we don't use Go escape sequences,
// we treat the string as a byte sequence, and we use octal escapes.
// These differences are to maintain interoperability with the other
// languages' implementations of the text format.
func writeString(w *textWriter, s string) error {
// use WriteByte here to get any needed indent
if err := w.WriteByte('"'); err != nil {
return err
}
// Loop over the bytes, not the runes.
for i := 0; i < len(s); i++ {
var err error
// Divergence from C++: we don't escape apostrophes.
// There's no need to escape them, and the C++ parser
// copes with a naked apostrophe.
switch c := s[i]; c {
case '\n':
_, err = w.w.Write(backslashN)
case '\r':
_, err = w.w.Write(backslashR)
case '\t':
_, err = w.w.Write(backslashT)
case '"':
_, err = w.w.Write(backslashDQ)
case '\\':
_, err = w.w.Write(backslashBS)
default:
if isprint(c) {
err = w.w.WriteByte(c)
} else {
_, err = fmt.Fprintf(w.w, "\\%03o", c)
}
}
if err != nil {
return err
}
}
return w.WriteByte('"')
}
func writeUnknownStruct(w *textWriter, data []byte) (err error) {
if !w.compact {
if _, err := fmt.Fprintf(w, "/* %d unknown bytes */\n", len(data)); err != nil {
return err
}
}
b := NewBuffer(data)
for b.index < len(b.buf) {
x, err := b.DecodeVarint()
if err != nil {
_, err := fmt.Fprintf(w, "/* %v */\n", err)
return err
}
wire, tag := x&7, x>>3
if wire == WireEndGroup {
w.unindent()
if _, err := w.Write(endBraceNewline); err != nil {
return err
}
continue
}
if _, err := fmt.Fprint(w, tag); err != nil {
return err
}
if wire != WireStartGroup {
if err := w.WriteByte(':'); err != nil {
return err
}
}
if !w.compact || wire == WireStartGroup {
if err := w.WriteByte(' '); err != nil {
return err
}
}
switch wire {
case WireBytes:
buf, e := b.DecodeRawBytes(false)
if e == nil {
_, err = fmt.Fprintf(w, "%q", buf)
} else {
_, err = fmt.Fprintf(w, "/* %v */", e)
}
case WireFixed32:
x, err = b.DecodeFixed32()
err = writeUnknownInt(w, x, err)
case WireFixed64:
x, err = b.DecodeFixed64()
err = writeUnknownInt(w, x, err)
case WireStartGroup:
err = w.WriteByte('{')
w.indent()
case WireVarint:
x, err = b.DecodeVarint()
err = writeUnknownInt(w, x, err)
default:
_, err = fmt.Fprintf(w, "/* unknown wire type %d */", wire)
}
if err != nil {
return err
}
if err = w.WriteByte('\n'); err != nil {
return err
}
}
return nil
}
func writeUnknownInt(w *textWriter, x uint64, err error) error {
if err == nil {
_, err = fmt.Fprint(w, x)
} else {
_, err = fmt.Fprintf(w, "/* %v */", err)
}
return err
}
type int32Slice []int32
func (s int32Slice) Len() int { return len(s) }
func (s int32Slice) Less(i, j int) bool { return s[i] < s[j] }
func (s int32Slice) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
// writeExtensions writes all the extensions in pv.
// pv is assumed to be a pointer to a protocol message struct that is extendable.
func (tm *TextMarshaler) writeExtensions(w *textWriter, pv reflect.Value) error {
emap := extensionMaps[pv.Type().Elem()]
ep, _ := extendable(pv.Interface())
// Order the extensions by ID.
// This isn't strictly necessary, but it will give us
// canonical output, which will also make testing easier.
m, mu := ep.extensionsRead()
if m == nil {
return nil
}
mu.Lock()
ids := make([]int32, 0, len(m))
for id := range m {
ids = append(ids, id)
}
sort.Sort(int32Slice(ids))
mu.Unlock()
for _, extNum := range ids {
ext := m[extNum]
var desc *ExtensionDesc
if emap != nil {
desc = emap[extNum]
}
if desc == nil {
// Unknown extension.
if err := writeUnknownStruct(w, ext.enc); err != nil {
return err
}
continue
}
pb, err := GetExtension(ep, desc)
if err != nil {
return fmt.Errorf("failed getting extension: %v", err)
}
// Repeated extensions will appear as a slice.
if !desc.repeated() {
if err := tm.writeExtension(w, desc.Name, pb); err != nil {
return err
}
} else {
v := reflect.ValueOf(pb)
for i := 0; i < v.Len(); i++ {
if err := tm.writeExtension(w, desc.Name, v.Index(i).Interface()); err != nil {
return err
}
}
}
}
return nil
}
func (tm *TextMarshaler) writeExtension(w *textWriter, name string, pb interface{}) error {
if _, err := fmt.Fprintf(w, "[%s]:", name); err != nil {
return err
}
if !w.compact {
if err := w.WriteByte(' '); err != nil {
return err
}
}
if err := tm.writeAny(w, reflect.ValueOf(pb), nil); err != nil {
return err
}
if err := w.WriteByte('\n'); err != nil {
return err
}
return nil
}
func (w *textWriter) writeIndent() {
if !w.complete {
return
}
remain := w.ind * 2
for remain > 0 {
n := remain
if n > len(spaces) {
n = len(spaces)
}
w.w.Write(spaces[:n])
remain -= n
}
w.complete = false
}
// TextMarshaler is a configurable text format marshaler.
type TextMarshaler struct {
Compact bool // use compact text format (one line).
ExpandAny bool // expand google.protobuf.Any messages of known types
}
// Marshal writes a given protocol buffer in text format.
// The only errors returned are from w.
func (tm *TextMarshaler) Marshal(w io.Writer, pb Message) error {
val := reflect.ValueOf(pb)
if pb == nil || val.IsNil() {
w.Write([]byte("<nil>"))
return nil
}
var bw *bufio.Writer
ww, ok := w.(writer)
if !ok {
bw = bufio.NewWriter(w)
ww = bw
}
aw := &textWriter{
w: ww,
complete: true,
compact: tm.Compact,
}
if etm, ok := pb.(encoding.TextMarshaler); ok {
text, err := etm.MarshalText()
if err != nil {
return err
}
if _, err = aw.Write(text); err != nil {
return err
}
if bw != nil {
return bw.Flush()
}
return nil
}
// Dereference the received pointer so we don't have outer < and >.
v := reflect.Indirect(val)
if err := tm.writeStruct(aw, v); err != nil {
return err
}
if bw != nil {
return bw.Flush()
}
return nil
}
// Text is the same as Marshal, but returns the string directly.
func (tm *TextMarshaler) Text(pb Message) string {
var buf bytes.Buffer
tm.Marshal(&buf, pb)
return buf.String()
}
var (
defaultTextMarshaler = TextMarshaler{}
compactTextMarshaler = TextMarshaler{Compact: true}
)
// TODO: consider removing some of the Marshal functions below.
// MarshalText writes a given protocol buffer in text format.
// The only errors returned are from w.
func MarshalText(w io.Writer, pb Message) error { return defaultTextMarshaler.Marshal(w, pb) }
// MarshalTextString is the same as MarshalText, but returns the string directly.
func MarshalTextString(pb Message) string { return defaultTextMarshaler.Text(pb) }
// CompactText writes a given protocol buffer in compact text format (one line).
func CompactText(w io.Writer, pb Message) error { return compactTextMarshaler.Marshal(w, pb) }
// CompactTextString is the same as CompactText, but returns the string directly.
func CompactTextString(pb Message) string { return compactTextMarshaler.Text(pb) }