You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
400 lines
13 KiB
Go
400 lines
13 KiB
Go
8 years ago
|
// 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
|
||
|
|
||
|
/*
|
||
|
* Types and routines for supporting protocol buffer extensions.
|
||
|
*/
|
||
|
|
||
|
import (
|
||
|
"errors"
|
||
|
"fmt"
|
||
|
"reflect"
|
||
|
"strconv"
|
||
|
"sync"
|
||
|
)
|
||
|
|
||
|
// ErrMissingExtension is the error returned by GetExtension if the named extension is not in the message.
|
||
|
var ErrMissingExtension = errors.New("proto: missing extension")
|
||
|
|
||
|
// ExtensionRange represents a range of message extensions for a protocol buffer.
|
||
|
// Used in code generated by the protocol compiler.
|
||
|
type ExtensionRange struct {
|
||
|
Start, End int32 // both inclusive
|
||
|
}
|
||
|
|
||
|
// extendableProto is an interface implemented by any protocol buffer that may be extended.
|
||
|
type extendableProto interface {
|
||
|
Message
|
||
|
ExtensionRangeArray() []ExtensionRange
|
||
|
ExtensionMap() map[int32]Extension
|
||
|
}
|
||
|
|
||
|
var extendableProtoType = reflect.TypeOf((*extendableProto)(nil)).Elem()
|
||
|
|
||
|
// ExtensionDesc represents an extension specification.
|
||
|
// Used in generated code from the protocol compiler.
|
||
|
type ExtensionDesc struct {
|
||
|
ExtendedType Message // nil pointer to the type that is being extended
|
||
|
ExtensionType interface{} // nil pointer to the extension type
|
||
|
Field int32 // field number
|
||
|
Name string // fully-qualified name of extension, for text formatting
|
||
|
Tag string // protobuf tag style
|
||
|
}
|
||
|
|
||
|
func (ed *ExtensionDesc) repeated() bool {
|
||
|
t := reflect.TypeOf(ed.ExtensionType)
|
||
|
return t.Kind() == reflect.Slice && t.Elem().Kind() != reflect.Uint8
|
||
|
}
|
||
|
|
||
|
// Extension represents an extension in a message.
|
||
|
type Extension struct {
|
||
|
// When an extension is stored in a message using SetExtension
|
||
|
// only desc and value are set. When the message is marshaled
|
||
|
// enc will be set to the encoded form of the message.
|
||
|
//
|
||
|
// When a message is unmarshaled and contains extensions, each
|
||
|
// extension will have only enc set. When such an extension is
|
||
|
// accessed using GetExtension (or GetExtensions) desc and value
|
||
|
// will be set.
|
||
|
desc *ExtensionDesc
|
||
|
value interface{}
|
||
|
enc []byte
|
||
|
}
|
||
|
|
||
|
// SetRawExtension is for testing only.
|
||
|
func SetRawExtension(base extendableProto, id int32, b []byte) {
|
||
|
base.ExtensionMap()[id] = Extension{enc: b}
|
||
|
}
|
||
|
|
||
|
// isExtensionField returns true iff the given field number is in an extension range.
|
||
|
func isExtensionField(pb extendableProto, field int32) bool {
|
||
|
for _, er := range pb.ExtensionRangeArray() {
|
||
|
if er.Start <= field && field <= er.End {
|
||
|
return true
|
||
|
}
|
||
|
}
|
||
|
return false
|
||
|
}
|
||
|
|
||
|
// checkExtensionTypes checks that the given extension is valid for pb.
|
||
|
func checkExtensionTypes(pb extendableProto, extension *ExtensionDesc) error {
|
||
|
// Check the extended type.
|
||
|
if a, b := reflect.TypeOf(pb), reflect.TypeOf(extension.ExtendedType); a != b {
|
||
|
return errors.New("proto: bad extended type; " + b.String() + " does not extend " + a.String())
|
||
|
}
|
||
|
// Check the range.
|
||
|
if !isExtensionField(pb, extension.Field) {
|
||
|
return errors.New("proto: bad extension number; not in declared ranges")
|
||
|
}
|
||
|
return nil
|
||
|
}
|
||
|
|
||
|
// extPropKey is sufficient to uniquely identify an extension.
|
||
|
type extPropKey struct {
|
||
|
base reflect.Type
|
||
|
field int32
|
||
|
}
|
||
|
|
||
|
var extProp = struct {
|
||
|
sync.RWMutex
|
||
|
m map[extPropKey]*Properties
|
||
|
}{
|
||
|
m: make(map[extPropKey]*Properties),
|
||
|
}
|
||
|
|
||
|
func extensionProperties(ed *ExtensionDesc) *Properties {
|
||
|
key := extPropKey{base: reflect.TypeOf(ed.ExtendedType), field: ed.Field}
|
||
|
|
||
|
extProp.RLock()
|
||
|
if prop, ok := extProp.m[key]; ok {
|
||
|
extProp.RUnlock()
|
||
|
return prop
|
||
|
}
|
||
|
extProp.RUnlock()
|
||
|
|
||
|
extProp.Lock()
|
||
|
defer extProp.Unlock()
|
||
|
// Check again.
|
||
|
if prop, ok := extProp.m[key]; ok {
|
||
|
return prop
|
||
|
}
|
||
|
|
||
|
prop := new(Properties)
|
||
|
prop.Init(reflect.TypeOf(ed.ExtensionType), "unknown_name", ed.Tag, nil)
|
||
|
extProp.m[key] = prop
|
||
|
return prop
|
||
|
}
|
||
|
|
||
|
// encodeExtensionMap encodes any unmarshaled (unencoded) extensions in m.
|
||
|
func encodeExtensionMap(m map[int32]Extension) error {
|
||
|
for k, e := range m {
|
||
|
if e.value == nil || e.desc == nil {
|
||
|
// Extension is only in its encoded form.
|
||
|
continue
|
||
|
}
|
||
|
|
||
|
// We don't skip extensions that have an encoded form set,
|
||
|
// because the extension value may have been mutated after
|
||
|
// the last time this function was called.
|
||
|
|
||
|
et := reflect.TypeOf(e.desc.ExtensionType)
|
||
|
props := extensionProperties(e.desc)
|
||
|
|
||
|
p := NewBuffer(nil)
|
||
|
// If e.value has type T, the encoder expects a *struct{ X T }.
|
||
|
// Pass a *T with a zero field and hope it all works out.
|
||
|
x := reflect.New(et)
|
||
|
x.Elem().Set(reflect.ValueOf(e.value))
|
||
|
if err := props.enc(p, props, toStructPointer(x)); err != nil {
|
||
|
return err
|
||
|
}
|
||
|
e.enc = p.buf
|
||
|
m[k] = e
|
||
|
}
|
||
|
return nil
|
||
|
}
|
||
|
|
||
|
func sizeExtensionMap(m map[int32]Extension) (n int) {
|
||
|
for _, e := range m {
|
||
|
if e.value == nil || e.desc == nil {
|
||
|
// Extension is only in its encoded form.
|
||
|
n += len(e.enc)
|
||
|
continue
|
||
|
}
|
||
|
|
||
|
// We don't skip extensions that have an encoded form set,
|
||
|
// because the extension value may have been mutated after
|
||
|
// the last time this function was called.
|
||
|
|
||
|
et := reflect.TypeOf(e.desc.ExtensionType)
|
||
|
props := extensionProperties(e.desc)
|
||
|
|
||
|
// If e.value has type T, the encoder expects a *struct{ X T }.
|
||
|
// Pass a *T with a zero field and hope it all works out.
|
||
|
x := reflect.New(et)
|
||
|
x.Elem().Set(reflect.ValueOf(e.value))
|
||
|
n += props.size(props, toStructPointer(x))
|
||
|
}
|
||
|
return
|
||
|
}
|
||
|
|
||
|
// HasExtension returns whether the given extension is present in pb.
|
||
|
func HasExtension(pb extendableProto, extension *ExtensionDesc) bool {
|
||
|
// TODO: Check types, field numbers, etc.?
|
||
|
_, ok := pb.ExtensionMap()[extension.Field]
|
||
|
return ok
|
||
|
}
|
||
|
|
||
|
// ClearExtension removes the given extension from pb.
|
||
|
func ClearExtension(pb extendableProto, extension *ExtensionDesc) {
|
||
|
// TODO: Check types, field numbers, etc.?
|
||
|
delete(pb.ExtensionMap(), extension.Field)
|
||
|
}
|
||
|
|
||
|
// GetExtension parses and returns the given extension of pb.
|
||
|
// If the extension is not present and has no default value it returns ErrMissingExtension.
|
||
|
func GetExtension(pb extendableProto, extension *ExtensionDesc) (interface{}, error) {
|
||
|
if err := checkExtensionTypes(pb, extension); err != nil {
|
||
|
return nil, err
|
||
|
}
|
||
|
|
||
|
emap := pb.ExtensionMap()
|
||
|
e, ok := emap[extension.Field]
|
||
|
if !ok {
|
||
|
// defaultExtensionValue returns the default value or
|
||
|
// ErrMissingExtension if there is no default.
|
||
|
return defaultExtensionValue(extension)
|
||
|
}
|
||
|
|
||
|
if e.value != nil {
|
||
|
// Already decoded. Check the descriptor, though.
|
||
|
if e.desc != extension {
|
||
|
// This shouldn't happen. If it does, it means that
|
||
|
// GetExtension was called twice with two different
|
||
|
// descriptors with the same field number.
|
||
|
return nil, errors.New("proto: descriptor conflict")
|
||
|
}
|
||
|
return e.value, nil
|
||
|
}
|
||
|
|
||
|
v, err := decodeExtension(e.enc, extension)
|
||
|
if err != nil {
|
||
|
return nil, err
|
||
|
}
|
||
|
|
||
|
// Remember the decoded version and drop the encoded version.
|
||
|
// That way it is safe to mutate what we return.
|
||
|
e.value = v
|
||
|
e.desc = extension
|
||
|
e.enc = nil
|
||
|
emap[extension.Field] = e
|
||
|
return e.value, nil
|
||
|
}
|
||
|
|
||
|
// defaultExtensionValue returns the default value for extension.
|
||
|
// If no default for an extension is defined ErrMissingExtension is returned.
|
||
|
func defaultExtensionValue(extension *ExtensionDesc) (interface{}, error) {
|
||
|
t := reflect.TypeOf(extension.ExtensionType)
|
||
|
props := extensionProperties(extension)
|
||
|
|
||
|
sf, _, err := fieldDefault(t, props)
|
||
|
if err != nil {
|
||
|
return nil, err
|
||
|
}
|
||
|
|
||
|
if sf == nil || sf.value == nil {
|
||
|
// There is no default value.
|
||
|
return nil, ErrMissingExtension
|
||
|
}
|
||
|
|
||
|
if t.Kind() != reflect.Ptr {
|
||
|
// We do not need to return a Ptr, we can directly return sf.value.
|
||
|
return sf.value, nil
|
||
|
}
|
||
|
|
||
|
// We need to return an interface{} that is a pointer to sf.value.
|
||
|
value := reflect.New(t).Elem()
|
||
|
value.Set(reflect.New(value.Type().Elem()))
|
||
|
if sf.kind == reflect.Int32 {
|
||
|
// We may have an int32 or an enum, but the underlying data is int32.
|
||
|
// Since we can't set an int32 into a non int32 reflect.value directly
|
||
|
// set it as a int32.
|
||
|
value.Elem().SetInt(int64(sf.value.(int32)))
|
||
|
} else {
|
||
|
value.Elem().Set(reflect.ValueOf(sf.value))
|
||
|
}
|
||
|
return value.Interface(), nil
|
||
|
}
|
||
|
|
||
|
// decodeExtension decodes an extension encoded in b.
|
||
|
func decodeExtension(b []byte, extension *ExtensionDesc) (interface{}, error) {
|
||
|
o := NewBuffer(b)
|
||
|
|
||
|
t := reflect.TypeOf(extension.ExtensionType)
|
||
|
|
||
|
props := extensionProperties(extension)
|
||
|
|
||
|
// t is a pointer to a struct, pointer to basic type or a slice.
|
||
|
// Allocate a "field" to store the pointer/slice itself; the
|
||
|
// pointer/slice will be stored here. We pass
|
||
|
// the address of this field to props.dec.
|
||
|
// This passes a zero field and a *t and lets props.dec
|
||
|
// interpret it as a *struct{ x t }.
|
||
|
value := reflect.New(t).Elem()
|
||
|
|
||
|
for {
|
||
|
// Discard wire type and field number varint. It isn't needed.
|
||
|
if _, err := o.DecodeVarint(); err != nil {
|
||
|
return nil, err
|
||
|
}
|
||
|
|
||
|
if err := props.dec(o, props, toStructPointer(value.Addr())); err != nil {
|
||
|
return nil, err
|
||
|
}
|
||
|
|
||
|
if o.index >= len(o.buf) {
|
||
|
break
|
||
|
}
|
||
|
}
|
||
|
return value.Interface(), nil
|
||
|
}
|
||
|
|
||
|
// GetExtensions returns a slice of the extensions present in pb that are also listed in es.
|
||
|
// The returned slice has the same length as es; missing extensions will appear as nil elements.
|
||
|
func GetExtensions(pb Message, es []*ExtensionDesc) (extensions []interface{}, err error) {
|
||
|
epb, ok := pb.(extendableProto)
|
||
|
if !ok {
|
||
|
err = errors.New("proto: not an extendable proto")
|
||
|
return
|
||
|
}
|
||
|
extensions = make([]interface{}, len(es))
|
||
|
for i, e := range es {
|
||
|
extensions[i], err = GetExtension(epb, e)
|
||
|
if err == ErrMissingExtension {
|
||
|
err = nil
|
||
|
}
|
||
|
if err != nil {
|
||
|
return
|
||
|
}
|
||
|
}
|
||
|
return
|
||
|
}
|
||
|
|
||
|
// SetExtension sets the specified extension of pb to the specified value.
|
||
|
func SetExtension(pb extendableProto, extension *ExtensionDesc, value interface{}) error {
|
||
|
if err := checkExtensionTypes(pb, extension); err != nil {
|
||
|
return err
|
||
|
}
|
||
|
typ := reflect.TypeOf(extension.ExtensionType)
|
||
|
if typ != reflect.TypeOf(value) {
|
||
|
return errors.New("proto: bad extension value type")
|
||
|
}
|
||
|
// nil extension values need to be caught early, because the
|
||
|
// encoder can't distinguish an ErrNil due to a nil extension
|
||
|
// from an ErrNil due to a missing field. Extensions are
|
||
|
// always optional, so the encoder would just swallow the error
|
||
|
// and drop all the extensions from the encoded message.
|
||
|
if reflect.ValueOf(value).IsNil() {
|
||
|
return fmt.Errorf("proto: SetExtension called with nil value of type %T", value)
|
||
|
}
|
||
|
|
||
|
pb.ExtensionMap()[extension.Field] = Extension{desc: extension, value: value}
|
||
|
return nil
|
||
|
}
|
||
|
|
||
|
// A global registry of extensions.
|
||
|
// The generated code will register the generated descriptors by calling RegisterExtension.
|
||
|
|
||
|
var extensionMaps = make(map[reflect.Type]map[int32]*ExtensionDesc)
|
||
|
|
||
|
// RegisterExtension is called from the generated code.
|
||
|
func RegisterExtension(desc *ExtensionDesc) {
|
||
|
st := reflect.TypeOf(desc.ExtendedType).Elem()
|
||
|
m := extensionMaps[st]
|
||
|
if m == nil {
|
||
|
m = make(map[int32]*ExtensionDesc)
|
||
|
extensionMaps[st] = m
|
||
|
}
|
||
|
if _, ok := m[desc.Field]; ok {
|
||
|
panic("proto: duplicate extension registered: " + st.String() + " " + strconv.Itoa(int(desc.Field)))
|
||
|
}
|
||
|
m[desc.Field] = desc
|
||
|
}
|
||
|
|
||
|
// RegisteredExtensions returns a map of the registered extensions of a
|
||
|
// protocol buffer struct, indexed by the extension number.
|
||
|
// The argument pb should be a nil pointer to the struct type.
|
||
|
func RegisteredExtensions(pb Message) map[int32]*ExtensionDesc {
|
||
|
return extensionMaps[reflect.TypeOf(pb).Elem()]
|
||
|
}
|