130 lines
2.7 KiB
Go
130 lines
2.7 KiB
Go
package typeurl
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import (
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"encoding/json"
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"path"
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"reflect"
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"strings"
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"sync"
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"github.com/containerd/containerd/errdefs"
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"github.com/gogo/protobuf/proto"
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"github.com/gogo/protobuf/types"
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)
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const Prefix = "types.containerd.io"
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var (
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mu sync.Mutex
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registry = make(map[reflect.Type]string)
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)
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// Register a type with the base url of the type
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func Register(v interface{}, args ...string) {
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t := tryDereference(v)
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mu.Lock()
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defer mu.Unlock()
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if _, ok := registry[t]; ok {
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panic(errdefs.ErrAlreadyExists)
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}
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registry[t] = path.Join(append([]string{Prefix}, args...)...)
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}
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// TypeURL returns the type url for a registred type
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func TypeURL(v interface{}) (string, error) {
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mu.Lock()
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u, ok := registry[tryDereference(v)]
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mu.Unlock()
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if !ok {
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// fallback to the proto registry if it is a proto message
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pb, ok := v.(proto.Message)
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if !ok {
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return "", errdefs.ErrNotFound
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}
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return path.Join(Prefix, proto.MessageName(pb)), nil
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}
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return u, nil
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}
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// Is returns true if the type of the Any is the same as v
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func Is(any *types.Any, v interface{}) bool {
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// call to check that v is a pointer
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tryDereference(v)
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url, err := TypeURL(v)
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if err != nil {
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return false
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}
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return any.TypeUrl == url
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}
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// MarshalAny marshals the value v into an any with the correct TypeUrl
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func MarshalAny(v interface{}) (*types.Any, error) {
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var data []byte
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url, err := TypeURL(v)
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if err != nil {
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return nil, err
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}
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switch t := v.(type) {
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case proto.Message:
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data, err = proto.Marshal(t)
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default:
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data, err = json.Marshal(v)
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}
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if err != nil {
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return nil, err
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}
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return &types.Any{
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TypeUrl: url,
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Value: data,
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}, nil
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}
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// UnmarshalAny unmarshals the any type into a concrete type
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func UnmarshalAny(any *types.Any) (interface{}, error) {
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t, err := getTypeByUrl(any.TypeUrl)
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if err != nil {
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return nil, err
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}
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v := reflect.New(t.t).Interface()
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if t.isProto {
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err = proto.Unmarshal(any.Value, v.(proto.Message))
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} else {
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err = json.Unmarshal(any.Value, v)
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}
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return v, err
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}
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type urlType struct {
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t reflect.Type
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isProto bool
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}
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func getTypeByUrl(url string) (urlType, error) {
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for t, u := range registry {
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if u == url {
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return urlType{
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t: t,
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}, nil
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}
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}
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// fallback to proto registry
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t := proto.MessageType(strings.TrimPrefix(url, Prefix+"/"))
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if t != nil {
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return urlType{
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// get the underlying Elem because proto returns a pointer to the type
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t: t.Elem(),
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isProto: true,
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}, nil
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}
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return urlType{}, errdefs.ErrNotFound
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}
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func tryDereference(v interface{}) reflect.Type {
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t := reflect.TypeOf(v)
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if t.Kind() == reflect.Ptr {
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// require check of pointer but dereference to register
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return t.Elem()
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}
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panic("v is not a pointer to a type")
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}
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