diff options
Diffstat (limited to 'vendor/github.com/golang/protobuf/proto/discard.go')
| -rw-r--r-- | vendor/github.com/golang/protobuf/proto/discard.go | 201 |
1 files changed, 200 insertions, 1 deletions
diff --git a/vendor/github.com/golang/protobuf/proto/discard.go b/vendor/github.com/golang/protobuf/proto/discard.go index bd0e3bb4c..dea2617ce 100644 --- a/vendor/github.com/golang/protobuf/proto/discard.go +++ b/vendor/github.com/golang/protobuf/proto/discard.go @@ -35,8 +35,14 @@ import ( "fmt" "reflect" "strings" + "sync" + "sync/atomic" ) +type generatedDiscarder interface { + XXX_DiscardUnknown() +} + // DiscardUnknown recursively discards all unknown fields from this message // and all embedded messages. // @@ -49,9 +55,202 @@ import ( // For proto2 messages, the unknown fields of message extensions are only // discarded from messages that have been accessed via GetExtension. func DiscardUnknown(m Message) { + if m, ok := m.(generatedDiscarder); ok { + m.XXX_DiscardUnknown() + return + } + // TODO: Dynamically populate a InternalMessageInfo for legacy messages, + // but the master branch has no implementation for InternalMessageInfo, + // so it would be more work to replicate that approach. discardLegacy(m) } +// DiscardUnknown recursively discards all unknown fields. +func (a *InternalMessageInfo) DiscardUnknown(m Message) { + di := atomicLoadDiscardInfo(&a.discard) + if di == nil { + di = getDiscardInfo(reflect.TypeOf(m).Elem()) + atomicStoreDiscardInfo(&a.discard, di) + } + di.discard(toPointer(&m)) +} + +type discardInfo struct { + typ reflect.Type + + initialized int32 // 0: only typ is valid, 1: everything is valid + lock sync.Mutex + + fields []discardFieldInfo + unrecognized field +} + +type discardFieldInfo struct { + field field // Offset of field, guaranteed to be valid + discard func(src pointer) +} + +var ( + discardInfoMap = map[reflect.Type]*discardInfo{} + discardInfoLock sync.Mutex +) + +func getDiscardInfo(t reflect.Type) *discardInfo { + discardInfoLock.Lock() + defer discardInfoLock.Unlock() + di := discardInfoMap[t] + if di == nil { + di = &discardInfo{typ: t} + discardInfoMap[t] = di + } + return di +} + +func (di *discardInfo) discard(src pointer) { + if src.isNil() { + return // Nothing to do. + } + + if atomic.LoadInt32(&di.initialized) == 0 { + di.computeDiscardInfo() + } + + for _, fi := range di.fields { + sfp := src.offset(fi.field) + fi.discard(sfp) + } + + // For proto2 messages, only discard unknown fields in message extensions + // that have been accessed via GetExtension. + if em, err := extendable(src.asPointerTo(di.typ).Interface()); err == nil { + // Ignore lock since DiscardUnknown is not concurrency safe. + emm, _ := em.extensionsRead() + for _, mx := range emm { + if m, ok := mx.value.(Message); ok { + DiscardUnknown(m) + } + } + } + + if di.unrecognized.IsValid() { + *src.offset(di.unrecognized).toBytes() = nil + } +} + +func (di *discardInfo) computeDiscardInfo() { + di.lock.Lock() + defer di.lock.Unlock() + if di.initialized != 0 { + return + } + t := di.typ + n := t.NumField() + + for i := 0; i < n; i++ { + f := t.Field(i) + if strings.HasPrefix(f.Name, "XXX_") { + continue + } + + dfi := discardFieldInfo{field: toField(&f)} + tf := f.Type + + // Unwrap tf to get its most basic type. + var isPointer, isSlice bool + if tf.Kind() == reflect.Slice && tf.Elem().Kind() != reflect.Uint8 { + isSlice = true + tf = tf.Elem() + } + if tf.Kind() == reflect.Ptr { + isPointer = true + tf = tf.Elem() + } + if isPointer && isSlice && tf.Kind() != reflect.Struct { + panic(fmt.Sprintf("%v.%s cannot be a slice of pointers to primitive types", t, f.Name)) + } + + switch tf.Kind() { + case reflect.Struct: + switch { + case !isPointer: + panic(fmt.Sprintf("%v.%s cannot be a direct struct value", t, f.Name)) + case isSlice: // E.g., []*pb.T + di := getDiscardInfo(tf) + dfi.discard = func(src pointer) { + sps := src.getPointerSlice() + for _, sp := range sps { + if !sp.isNil() { + di.discard(sp) + } + } + } + default: // E.g., *pb.T + di := getDiscardInfo(tf) + dfi.discard = func(src pointer) { + sp := src.getPointer() + if !sp.isNil() { + di.discard(sp) + } + } + } + case reflect.Map: + switch { + case isPointer || isSlice: + panic(fmt.Sprintf("%v.%s cannot be a pointer to a map or a slice of map values", t, f.Name)) + default: // E.g., map[K]V + if tf.Elem().Kind() == reflect.Ptr { // Proto struct (e.g., *T) + dfi.discard = func(src pointer) { + sm := src.asPointerTo(tf).Elem() + if sm.Len() == 0 { + return + } + for _, key := range sm.MapKeys() { + val := sm.MapIndex(key) + DiscardUnknown(val.Interface().(Message)) + } + } + } else { + dfi.discard = func(pointer) {} // Noop + } + } + case reflect.Interface: + // Must be oneof field. + switch { + case isPointer || isSlice: + panic(fmt.Sprintf("%v.%s cannot be a pointer to a interface or a slice of interface values", t, f.Name)) + default: // E.g., interface{} + // TODO: Make this faster? + dfi.discard = func(src pointer) { + su := src.asPointerTo(tf).Elem() + if !su.IsNil() { + sv := su.Elem().Elem().Field(0) + if sv.Kind() == reflect.Ptr && sv.IsNil() { + return + } + switch sv.Type().Kind() { + case reflect.Ptr: // Proto struct (e.g., *T) + DiscardUnknown(sv.Interface().(Message)) + } + } + } + } + default: + continue + } + di.fields = append(di.fields, dfi) + } + + di.unrecognized = invalidField + if f, ok := t.FieldByName("XXX_unrecognized"); ok { + if f.Type != reflect.TypeOf([]byte{}) { + panic("expected XXX_unrecognized to be of type []byte") + } + di.unrecognized = toField(&f) + } + + atomic.StoreInt32(&di.initialized, 1) +} + func discardLegacy(m Message) { v := reflect.ValueOf(m) if v.Kind() != reflect.Ptr || v.IsNil() { @@ -139,7 +338,7 @@ func discardLegacy(m Message) { // For proto2 messages, only discard unknown fields in message extensions // that have been accessed via GetExtension. - if em, ok := extendable(m); ok { + if em, err := extendable(m); err == nil { // Ignore lock since discardLegacy is not concurrency safe. emm, _ := em.extensionsRead() for _, mx := range emm { |