Import of https://github.com/ciena/voltctl at commit 40d61fbf3f910ed4017cf67c9c79e8e1f82a33a5

Change-Id: I8464c59e60d76cb8612891db3303878975b5416c
diff --git a/vendor/github.com/jhump/protoreflect/desc/load.go b/vendor/github.com/jhump/protoreflect/desc/load.go
new file mode 100644
index 0000000..4a05830
--- /dev/null
+++ b/vendor/github.com/jhump/protoreflect/desc/load.go
@@ -0,0 +1,341 @@
+package desc
+
+import (
+	"fmt"
+	"reflect"
+	"sync"
+
+	"github.com/golang/protobuf/proto"
+	dpb "github.com/golang/protobuf/protoc-gen-go/descriptor"
+
+	"github.com/jhump/protoreflect/internal"
+)
+
+var (
+	cacheMu       sync.RWMutex
+	filesCache    = map[string]*FileDescriptor{}
+	messagesCache = map[string]*MessageDescriptor{}
+	enumCache     = map[reflect.Type]*EnumDescriptor{}
+)
+
+// LoadFileDescriptor creates a file descriptor using the bytes returned by
+// proto.FileDescriptor. Descriptors are cached so that they do not need to be
+// re-processed if the same file is fetched again later.
+func LoadFileDescriptor(file string) (*FileDescriptor, error) {
+	return loadFileDescriptor(file, nil)
+}
+
+func loadFileDescriptor(file string, r *ImportResolver) (*FileDescriptor, error) {
+	f := getFileFromCache(file)
+	if f != nil {
+		return f, nil
+	}
+	cacheMu.Lock()
+	defer cacheMu.Unlock()
+	return loadFileDescriptorLocked(file, r)
+}
+
+func loadFileDescriptorLocked(file string, r *ImportResolver) (*FileDescriptor, error) {
+	f := filesCache[file]
+	if f != nil {
+		return f, nil
+	}
+	fd, err := internal.LoadFileDescriptor(file)
+	if err != nil {
+		return nil, err
+	}
+
+	f, err = toFileDescriptorLocked(fd, r)
+	if err != nil {
+		return nil, err
+	}
+	putCacheLocked(file, f)
+	return f, nil
+}
+
+func toFileDescriptorLocked(fd *dpb.FileDescriptorProto, r *ImportResolver) (*FileDescriptor, error) {
+	deps := make([]*FileDescriptor, len(fd.GetDependency()))
+	for i, dep := range fd.GetDependency() {
+		resolvedDep := r.ResolveImport(fd.GetName(), dep)
+		var err error
+		deps[i], err = loadFileDescriptorLocked(resolvedDep, r)
+		if _, ok := err.(internal.ErrNoSuchFile); ok && resolvedDep != dep {
+			// try original path
+			deps[i], err = loadFileDescriptorLocked(dep, r)
+		}
+		if err != nil {
+			return nil, err
+		}
+	}
+	return CreateFileDescriptor(fd, deps...)
+}
+
+func getFileFromCache(file string) *FileDescriptor {
+	cacheMu.RLock()
+	defer cacheMu.RUnlock()
+	return filesCache[file]
+}
+
+func putCacheLocked(filename string, fd *FileDescriptor) {
+	filesCache[filename] = fd
+	putMessageCacheLocked(fd.messages)
+}
+
+func putMessageCacheLocked(mds []*MessageDescriptor) {
+	for _, md := range mds {
+		messagesCache[md.fqn] = md
+		putMessageCacheLocked(md.nested)
+	}
+}
+
+// interface implemented by generated messages, which all have a Descriptor() method in
+// addition to the methods of proto.Message
+type protoMessage interface {
+	proto.Message
+	Descriptor() ([]byte, []int)
+}
+
+// LoadMessageDescriptor loads descriptor using the encoded descriptor proto returned by
+// Message.Descriptor() for the given message type. If the given type is not recognized,
+// then a nil descriptor is returned.
+func LoadMessageDescriptor(message string) (*MessageDescriptor, error) {
+	return loadMessageDescriptor(message, nil)
+}
+
+func loadMessageDescriptor(message string, r *ImportResolver) (*MessageDescriptor, error) {
+	m := getMessageFromCache(message)
+	if m != nil {
+		return m, nil
+	}
+
+	pt := proto.MessageType(message)
+	if pt == nil {
+		return nil, nil
+	}
+	msg, err := messageFromType(pt)
+	if err != nil {
+		return nil, err
+	}
+
+	cacheMu.Lock()
+	defer cacheMu.Unlock()
+	return loadMessageDescriptorForTypeLocked(message, msg, r)
+}
+
+// LoadMessageDescriptorForType loads descriptor using the encoded descriptor proto returned
+// by message.Descriptor() for the given message type. If the given type is not recognized,
+// then a nil descriptor is returned.
+func LoadMessageDescriptorForType(messageType reflect.Type) (*MessageDescriptor, error) {
+	return loadMessageDescriptorForType(messageType, nil)
+}
+
+func loadMessageDescriptorForType(messageType reflect.Type, r *ImportResolver) (*MessageDescriptor, error) {
+	m, err := messageFromType(messageType)
+	if err != nil {
+		return nil, err
+	}
+	return loadMessageDescriptorForMessage(m, r)
+}
+
+// LoadMessageDescriptorForMessage loads descriptor using the encoded descriptor proto
+// returned by message.Descriptor(). If the given type is not recognized, then a nil
+// descriptor is returned.
+func LoadMessageDescriptorForMessage(message proto.Message) (*MessageDescriptor, error) {
+	return loadMessageDescriptorForMessage(message, nil)
+}
+
+func loadMessageDescriptorForMessage(message proto.Message, r *ImportResolver) (*MessageDescriptor, error) {
+	// efficiently handle dynamic messages
+	type descriptorable interface {
+		GetMessageDescriptor() *MessageDescriptor
+	}
+	if d, ok := message.(descriptorable); ok {
+		return d.GetMessageDescriptor(), nil
+	}
+
+	name := proto.MessageName(message)
+	if name == "" {
+		return nil, nil
+	}
+	m := getMessageFromCache(name)
+	if m != nil {
+		return m, nil
+	}
+
+	cacheMu.Lock()
+	defer cacheMu.Unlock()
+	return loadMessageDescriptorForTypeLocked(name, message.(protoMessage), nil)
+}
+
+func messageFromType(mt reflect.Type) (protoMessage, error) {
+	if mt.Kind() != reflect.Ptr {
+		mt = reflect.PtrTo(mt)
+	}
+	m, ok := reflect.Zero(mt).Interface().(protoMessage)
+	if !ok {
+		return nil, fmt.Errorf("failed to create message from type: %v", mt)
+	}
+	return m, nil
+}
+
+func loadMessageDescriptorForTypeLocked(name string, message protoMessage, r *ImportResolver) (*MessageDescriptor, error) {
+	m := messagesCache[name]
+	if m != nil {
+		return m, nil
+	}
+
+	fdb, _ := message.Descriptor()
+	fd, err := internal.DecodeFileDescriptor(name, fdb)
+	if err != nil {
+		return nil, err
+	}
+
+	f, err := toFileDescriptorLocked(fd, r)
+	if err != nil {
+		return nil, err
+	}
+	putCacheLocked(fd.GetName(), f)
+	return f.FindSymbol(name).(*MessageDescriptor), nil
+}
+
+func getMessageFromCache(message string) *MessageDescriptor {
+	cacheMu.RLock()
+	defer cacheMu.RUnlock()
+	return messagesCache[message]
+}
+
+// interface implemented by all generated enums
+type protoEnum interface {
+	EnumDescriptor() ([]byte, []int)
+}
+
+// NB: There is no LoadEnumDescriptor that takes a fully-qualified enum name because
+// it is not useful since protoc-gen-go does not expose the name anywhere in generated
+// code or register it in a way that is it accessible for reflection code. This also
+// means we have to cache enum descriptors differently -- we can only cache them as
+// they are requested, as opposed to caching all enum types whenever a file descriptor
+// is cached. This is because we need to know the generated type of the enums, and we
+// don't know that at the time of caching file descriptors.
+
+// LoadEnumDescriptorForType loads descriptor using the encoded descriptor proto returned
+// by enum.EnumDescriptor() for the given enum type.
+func LoadEnumDescriptorForType(enumType reflect.Type) (*EnumDescriptor, error) {
+	return loadEnumDescriptorForType(enumType, nil)
+}
+
+func loadEnumDescriptorForType(enumType reflect.Type, r *ImportResolver) (*EnumDescriptor, error) {
+	// we cache descriptors using non-pointer type
+	if enumType.Kind() == reflect.Ptr {
+		enumType = enumType.Elem()
+	}
+	e := getEnumFromCache(enumType)
+	if e != nil {
+		return e, nil
+	}
+	enum, err := enumFromType(enumType)
+	if err != nil {
+		return nil, err
+	}
+
+	cacheMu.Lock()
+	defer cacheMu.Unlock()
+	return loadEnumDescriptorForTypeLocked(enumType, enum, r)
+}
+
+// LoadEnumDescriptorForEnum loads descriptor using the encoded descriptor proto
+// returned by enum.EnumDescriptor().
+func LoadEnumDescriptorForEnum(enum protoEnum) (*EnumDescriptor, error) {
+	return loadEnumDescriptorForEnum(enum, nil)
+}
+
+func loadEnumDescriptorForEnum(enum protoEnum, r *ImportResolver) (*EnumDescriptor, error) {
+	et := reflect.TypeOf(enum)
+	// we cache descriptors using non-pointer type
+	if et.Kind() == reflect.Ptr {
+		et = et.Elem()
+		enum = reflect.Zero(et).Interface().(protoEnum)
+	}
+	e := getEnumFromCache(et)
+	if e != nil {
+		return e, nil
+	}
+
+	cacheMu.Lock()
+	defer cacheMu.Unlock()
+	return loadEnumDescriptorForTypeLocked(et, enum, r)
+}
+
+func enumFromType(et reflect.Type) (protoEnum, error) {
+	if et.Kind() != reflect.Int32 {
+		et = reflect.PtrTo(et)
+	}
+	e, ok := reflect.Zero(et).Interface().(protoEnum)
+	if !ok {
+		return nil, fmt.Errorf("failed to create enum from type: %v", et)
+	}
+	return e, nil
+}
+
+func loadEnumDescriptorForTypeLocked(et reflect.Type, enum protoEnum, r *ImportResolver) (*EnumDescriptor, error) {
+	e := enumCache[et]
+	if e != nil {
+		return e, nil
+	}
+
+	fdb, path := enum.EnumDescriptor()
+	name := fmt.Sprintf("%v", et)
+	fd, err := internal.DecodeFileDescriptor(name, fdb)
+	if err != nil {
+		return nil, err
+	}
+	// see if we already have cached "rich" descriptor
+	f, ok := filesCache[fd.GetName()]
+	if !ok {
+		f, err = toFileDescriptorLocked(fd, r)
+		if err != nil {
+			return nil, err
+		}
+		putCacheLocked(fd.GetName(), f)
+	}
+
+	ed := findEnum(f, path)
+	enumCache[et] = ed
+	return ed, nil
+}
+
+func getEnumFromCache(et reflect.Type) *EnumDescriptor {
+	cacheMu.RLock()
+	defer cacheMu.RUnlock()
+	return enumCache[et]
+}
+
+func findEnum(fd *FileDescriptor, path []int) *EnumDescriptor {
+	if len(path) == 1 {
+		return fd.GetEnumTypes()[path[0]]
+	}
+	md := fd.GetMessageTypes()[path[0]]
+	for _, i := range path[1 : len(path)-1] {
+		md = md.GetNestedMessageTypes()[i]
+	}
+	return md.GetNestedEnumTypes()[path[len(path)-1]]
+}
+
+// LoadFieldDescriptorForExtension loads the field descriptor that corresponds to the given
+// extension description.
+func LoadFieldDescriptorForExtension(ext *proto.ExtensionDesc) (*FieldDescriptor, error) {
+	return loadFieldDescriptorForExtension(ext, nil)
+}
+
+func loadFieldDescriptorForExtension(ext *proto.ExtensionDesc, r *ImportResolver) (*FieldDescriptor, error) {
+	file, err := loadFileDescriptor(ext.Filename, r)
+	if err != nil {
+		return nil, err
+	}
+	field, ok := file.FindSymbol(ext.Name).(*FieldDescriptor)
+	// make sure descriptor agrees with attributes of the ExtensionDesc
+	if !ok || !field.IsExtension() || field.GetOwner().GetFullyQualifiedName() != proto.MessageName(ext.ExtendedType) ||
+		field.GetNumber() != ext.Field {
+		return nil, fmt.Errorf("file descriptor contained unexpected object with name %s", ext.Name)
+	}
+	return field, nil
+}