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Diffstat (limited to 'vendor/github.com/golang/protobuf/proto/extensions.go')
| -rw-r--r-- | vendor/github.com/golang/protobuf/proto/extensions.go | 587 |
1 files changed, 587 insertions, 0 deletions
diff --git a/vendor/github.com/golang/protobuf/proto/extensions.go b/vendor/github.com/golang/protobuf/proto/extensions.go new file mode 100644 index 000000000..eaad21831 --- /dev/null +++ b/vendor/github.com/golang/protobuf/proto/extensions.go @@ -0,0 +1,587 @@ +// 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 generated by the current +// proto compiler that may be extended. +type extendableProto interface { + Message + ExtensionRangeArray() []ExtensionRange + extensionsWrite() map[int32]Extension + extensionsRead() (map[int32]Extension, sync.Locker) +} + +// extendableProtoV1 is an interface implemented by a protocol buffer generated by the previous +// version of the proto compiler that may be extended. +type extendableProtoV1 interface { + Message + ExtensionRangeArray() []ExtensionRange + ExtensionMap() map[int32]Extension +} + +// extensionAdapter is a wrapper around extendableProtoV1 that implements extendableProto. +type extensionAdapter struct { + extendableProtoV1 +} + +func (e extensionAdapter) extensionsWrite() map[int32]Extension { + return e.ExtensionMap() +} + +func (e extensionAdapter) extensionsRead() (map[int32]Extension, sync.Locker) { + return e.ExtensionMap(), notLocker{} +} + +// notLocker is a sync.Locker whose Lock and Unlock methods are nops. +type notLocker struct{} + +func (n notLocker) Lock() {} +func (n notLocker) Unlock() {} + +// extendable returns the extendableProto interface for the given generated proto message. +// If the proto message has the old extension format, it returns a wrapper that implements +// the extendableProto interface. +func extendable(p interface{}) (extendableProto, bool) { + if ep, ok := p.(extendableProto); ok { + return ep, ok + } + if ep, ok := p.(extendableProtoV1); ok { + return extensionAdapter{ep}, ok + } + return nil, false +} + +// XXX_InternalExtensions is an internal representation of proto extensions. +// +// Each generated message struct type embeds an anonymous XXX_InternalExtensions field, +// thus gaining the unexported 'extensions' method, which can be called only from the proto package. +// +// The methods of XXX_InternalExtensions are not concurrency safe in general, +// but calls to logically read-only methods such as has and get may be executed concurrently. +type XXX_InternalExtensions struct { + // The struct must be indirect so that if a user inadvertently copies a + // generated message and its embedded XXX_InternalExtensions, they + // avoid the mayhem of a copied mutex. + // + // The mutex serializes all logically read-only operations to p.extensionMap. + // It is up to the client to ensure that write operations to p.extensionMap are + // mutually exclusive with other accesses. + p *struct { + mu sync.Mutex + extensionMap map[int32]Extension + } +} + +// extensionsWrite returns the extension map, creating it on first use. +func (e *XXX_InternalExtensions) extensionsWrite() map[int32]Extension { + if e.p == nil { + e.p = new(struct { + mu sync.Mutex + extensionMap map[int32]Extension + }) + e.p.extensionMap = make(map[int32]Extension) + } + return e.p.extensionMap +} + +// extensionsRead returns the extensions map for read-only use. It may be nil. +// The caller must hold the returned mutex's lock when accessing Elements within the map. +func (e *XXX_InternalExtensions) extensionsRead() (map[int32]Extension, sync.Locker) { + if e.p == nil { + return nil, nil + } + return e.p.extensionMap, &e.p.mu +} + +var extendableProtoType = reflect.TypeOf((*extendableProto)(nil)).Elem() +var extendableProtoV1Type = reflect.TypeOf((*extendableProtoV1)(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 + Filename string // name of the file in which the extension is defined +} + +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 Message, id int32, b []byte) { + epb, ok := extendable(base) + if !ok { + return + } + extmap := epb.extensionsWrite() + extmap[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 { + var pbi interface{} = pb + // Check the extended type. + if ea, ok := pbi.(extensionAdapter); ok { + pbi = ea.extendableProtoV1 + } + if a, b := reflect.TypeOf(pbi), 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 +} + +// encode encodes any unmarshaled (unencoded) extensions in e. +func encodeExtensions(e *XXX_InternalExtensions) error { + m, mu := e.extensionsRead() + if m == nil { + return nil // fast path + } + mu.Lock() + defer mu.Unlock() + return encodeExtensionsMap(m) +} + +// encode encodes any unmarshaled (unencoded) extensions in e. +func encodeExtensionsMap(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 extensionsSize(e *XXX_InternalExtensions) (n int) { + m, mu := e.extensionsRead() + if m == nil { + return 0 + } + mu.Lock() + defer mu.Unlock() + return extensionsMapSize(m) +} + +func extensionsMapSize(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 Message, extension *ExtensionDesc) bool { + // TODO: Check types, field numbers, etc.? + epb, ok := extendable(pb) + if !ok { + return false + } + extmap, mu := epb.extensionsRead() + if extmap == nil { + return false + } + mu.Lock() + _, ok = extmap[extension.Field] + mu.Unlock() + return ok +} + +// ClearExtension removes the given extension from pb. +func ClearExtension(pb Message, extension *ExtensionDesc) { + epb, ok := extendable(pb) + if !ok { + return + } + // TODO: Check types, field numbers, etc.? + extmap := epb.extensionsWrite() + delete(extmap, 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 Message, extension *ExtensionDesc) (interface{}, error) { + epb, ok := extendable(pb) + if !ok { + return nil, errors.New("proto: not an extendable proto") + } + + if err := checkExtensionTypes(epb, extension); err != nil { + return nil, err + } + + emap, mu := epb.extensionsRead() + if emap == nil { + return defaultExtensionValue(extension) + } + mu.Lock() + defer mu.Unlock() + 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 := extendable(pb) + if !ok { + return nil, errors.New("proto: not an extendable proto") + } + 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 +} + +// ExtensionDescs returns a new slice containing pb's extension descriptors, in undefined order. +// For non-registered extensions, ExtensionDescs returns an incomplete descriptor containing +// just the Field field, which defines the extension's field number. +func ExtensionDescs(pb Message) ([]*ExtensionDesc, error) { + epb, ok := extendable(pb) + if !ok { + return nil, fmt.Errorf("proto: %T is not an extendable proto.Message", pb) + } + registeredExtensions := RegisteredExtensions(pb) + + emap, mu := epb.extensionsRead() + if emap == nil { + return nil, nil + } + mu.Lock() + defer mu.Unlock() + extensions := make([]*ExtensionDesc, 0, len(emap)) + for extid, e := range emap { + desc := e.desc + if desc == nil { + desc = registeredExtensions[extid] + if desc == nil { + desc = &ExtensionDesc{Field: extid} + } + } + + extensions = append(extensions, desc) + } + return extensions, nil +} + +// SetExtension sets the specified extension of pb to the specified value. +func SetExtension(pb Message, extension *ExtensionDesc, value interface{}) error { + epb, ok := extendable(pb) + if !ok { + return errors.New("proto: not an extendable proto") + } + if err := checkExtensionTypes(epb, 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) + } + + extmap := epb.extensionsWrite() + extmap[extension.Field] = Extension{desc: extension, value: value} + return nil +} + +// ClearAllExtensions clears all extensions from pb. +func ClearAllExtensions(pb Message) { + epb, ok := extendable(pb) + if !ok { + return + } + m := epb.extensionsWrite() + for k := range m { + delete(m, k) + } +} + +// 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()] +} |