gtsocial-umbx

desc.go (10574B)

---

 // Copyright 2018 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 // Package protodesc provides functionality for converting
 // FileDescriptorProto messages to/from protoreflect.FileDescriptor values.
 //
 // The google.protobuf.FileDescriptorProto is a protobuf message that describes
 // the type information for a .proto file in a form that is easily serializable.
 // The protoreflect.FileDescriptor is a more structured representation of
 // the FileDescriptorProto message where references and remote dependencies
 // can be directly followed.
 package protodesc
 
 import (
 	"google.golang.org/protobuf/internal/errors"
 	"google.golang.org/protobuf/internal/filedesc"
 	"google.golang.org/protobuf/internal/pragma"
 	"google.golang.org/protobuf/internal/strs"
 	"google.golang.org/protobuf/proto"
 	"google.golang.org/protobuf/reflect/protoreflect"
 	"google.golang.org/protobuf/reflect/protoregistry"
 
 	"google.golang.org/protobuf/types/descriptorpb"
 )
 
 // Resolver is the resolver used by NewFile to resolve dependencies.
 // The enums and messages provided must belong to some parent file,
 // which is also registered.
 //
 // It is implemented by protoregistry.Files.
 type Resolver interface {
 	FindFileByPath(string) (protoreflect.FileDescriptor, error)
 	FindDescriptorByName(protoreflect.FullName) (protoreflect.Descriptor, error)
 }
 
 // FileOptions configures the construction of file descriptors.
 type FileOptions struct {
 	pragma.NoUnkeyedLiterals
 
 	// AllowUnresolvable configures New to permissively allow unresolvable
 	// file, enum, or message dependencies. Unresolved dependencies are replaced
 	// by placeholder equivalents.
 	//
 	// The following dependencies may be left unresolved:
 	//	• Resolving an imported file.
 	//	• Resolving the type for a message field or extension field.
 	//	If the kind of the field is unknown, then a placeholder is used for both
 	//	the Enum and Message accessors on the protoreflect.FieldDescriptor.
 	//	• Resolving an enum value set as the default for an optional enum field.
 	//	If unresolvable, the protoreflect.FieldDescriptor.Default is set to the
 	//	first value in the associated enum (or zero if the also enum dependency
 	//	is also unresolvable). The protoreflect.FieldDescriptor.DefaultEnumValue
 	//	is populated with a placeholder.
 	//	• Resolving the extended message type for an extension field.
 	//	• Resolving the input or output message type for a service method.
 	//
 	// If the unresolved dependency uses a relative name,
 	// then the placeholder will contain an invalid FullName with a "*." prefix,
 	// indicating that the starting prefix of the full name is unknown.
 	AllowUnresolvable bool
 }
 
 // NewFile creates a new protoreflect.FileDescriptor from the provided
 // file descriptor message. See FileOptions.New for more information.
 func NewFile(fd *descriptorpb.FileDescriptorProto, r Resolver) (protoreflect.FileDescriptor, error) {
 	return FileOptions{}.New(fd, r)
 }
 
 // NewFiles creates a new protoregistry.Files from the provided
 // FileDescriptorSet message. See FileOptions.NewFiles for more information.
 func NewFiles(fd *descriptorpb.FileDescriptorSet) (*protoregistry.Files, error) {
 	return FileOptions{}.NewFiles(fd)
 }
 
 // New creates a new protoreflect.FileDescriptor from the provided
 // file descriptor message. The file must represent a valid proto file according
 // to protobuf semantics. The returned descriptor is a deep copy of the input.
 //
 // Any imported files, enum types, or message types referenced in the file are
 // resolved using the provided registry. When looking up an import file path,
 // the path must be unique. The newly created file descriptor is not registered
 // back into the provided file registry.
 func (o FileOptions) New(fd *descriptorpb.FileDescriptorProto, r Resolver) (protoreflect.FileDescriptor, error) {
 	if r == nil {
 		r = (*protoregistry.Files)(nil) // empty resolver
 	}
 
 	// Handle the file descriptor content.
 	f := &filedesc.File{L2: &filedesc.FileL2{}}
 	switch fd.GetSyntax() {
 	case "proto2", "":
 		f.L1.Syntax = protoreflect.Proto2
 	case "proto3":
 		f.L1.Syntax = protoreflect.Proto3
 	default:
 		return nil, errors.New("invalid syntax: %q", fd.GetSyntax())
 	}
 	f.L1.Path = fd.GetName()
 	if f.L1.Path == "" {
 		return nil, errors.New("file path must be populated")
 	}
 	f.L1.Package = protoreflect.FullName(fd.GetPackage())
 	if !f.L1.Package.IsValid() && f.L1.Package != "" {
 		return nil, errors.New("invalid package: %q", f.L1.Package)
 	}
 	if opts := fd.GetOptions(); opts != nil {
 		opts = proto.Clone(opts).(*descriptorpb.FileOptions)
 		f.L2.Options = func() protoreflect.ProtoMessage { return opts }
 	}
 
 	f.L2.Imports = make(filedesc.FileImports, len(fd.GetDependency()))
 	for _, i := range fd.GetPublicDependency() {
 		if !(0 <= i && int(i) < len(f.L2.Imports)) || f.L2.Imports[i].IsPublic {
 			return nil, errors.New("invalid or duplicate public import index: %d", i)
 		}
 		f.L2.Imports[i].IsPublic = true
 	}
 	for _, i := range fd.GetWeakDependency() {
 		if !(0 <= i && int(i) < len(f.L2.Imports)) || f.L2.Imports[i].IsWeak {
 			return nil, errors.New("invalid or duplicate weak import index: %d", i)
 		}
 		f.L2.Imports[i].IsWeak = true
 	}
 	imps := importSet{f.Path(): true}
 	for i, path := range fd.GetDependency() {
 		imp := &f.L2.Imports[i]
 		f, err := r.FindFileByPath(path)
 		if err == protoregistry.NotFound && (o.AllowUnresolvable || imp.IsWeak) {
 			f = filedesc.PlaceholderFile(path)
 		} else if err != nil {
 			return nil, errors.New("could not resolve import %q: %v", path, err)
 		}
 		imp.FileDescriptor = f
 
 		if imps[imp.Path()] {
 			return nil, errors.New("already imported %q", path)
 		}
 		imps[imp.Path()] = true
 	}
 	for i := range fd.GetDependency() {
 		imp := &f.L2.Imports[i]
 		imps.importPublic(imp.Imports())
 	}
 
 	// Handle source locations.
 	f.L2.Locations.File = f
 	for _, loc := range fd.GetSourceCodeInfo().GetLocation() {
 		var l protoreflect.SourceLocation
 		// TODO: Validate that the path points to an actual declaration?
 		l.Path = protoreflect.SourcePath(loc.GetPath())
 		s := loc.GetSpan()
 		switch len(s) {
 		case 3:
 			l.StartLine, l.StartColumn, l.EndLine, l.EndColumn = int(s[0]), int(s[1]), int(s[0]), int(s[2])
 		case 4:
 			l.StartLine, l.StartColumn, l.EndLine, l.EndColumn = int(s[0]), int(s[1]), int(s[2]), int(s[3])
 		default:
 			return nil, errors.New("invalid span: %v", s)
 		}
 		// TODO: Validate that the span information is sensible?
 		// See https://github.com/protocolbuffers/protobuf/issues/6378.
 		if false && (l.EndLine < l.StartLine || l.StartLine < 0 || l.StartColumn < 0 || l.EndColumn < 0 ||
 			(l.StartLine == l.EndLine && l.EndColumn <= l.StartColumn)) {
 			return nil, errors.New("invalid span: %v", s)
 		}
 		l.LeadingDetachedComments = loc.GetLeadingDetachedComments()
 		l.LeadingComments = loc.GetLeadingComments()
 		l.TrailingComments = loc.GetTrailingComments()
 		f.L2.Locations.List = append(f.L2.Locations.List, l)
 	}
 
 	// Step 1: Allocate and derive the names for all declarations.
 	// This copies all fields from the descriptor proto except:
 	//	google.protobuf.FieldDescriptorProto.type_name
 	//	google.protobuf.FieldDescriptorProto.default_value
 	//	google.protobuf.FieldDescriptorProto.oneof_index
 	//	google.protobuf.FieldDescriptorProto.extendee
 	//	google.protobuf.MethodDescriptorProto.input
 	//	google.protobuf.MethodDescriptorProto.output
 	var err error
 	sb := new(strs.Builder)
 	r1 := make(descsByName)
 	if f.L1.Enums.List, err = r1.initEnumDeclarations(fd.GetEnumType(), f, sb); err != nil {
 		return nil, err
 	}
 	if f.L1.Messages.List, err = r1.initMessagesDeclarations(fd.GetMessageType(), f, sb); err != nil {
 		return nil, err
 	}
 	if f.L1.Extensions.List, err = r1.initExtensionDeclarations(fd.GetExtension(), f, sb); err != nil {
 		return nil, err
 	}
 	if f.L1.Services.List, err = r1.initServiceDeclarations(fd.GetService(), f, sb); err != nil {
 		return nil, err
 	}
 
 	// Step 2: Resolve every dependency reference not handled by step 1.
 	r2 := &resolver{local: r1, remote: r, imports: imps, allowUnresolvable: o.AllowUnresolvable}
 	if err := r2.resolveMessageDependencies(f.L1.Messages.List, fd.GetMessageType()); err != nil {
 		return nil, err
 	}
 	if err := r2.resolveExtensionDependencies(f.L1.Extensions.List, fd.GetExtension()); err != nil {
 		return nil, err
 	}
 	if err := r2.resolveServiceDependencies(f.L1.Services.List, fd.GetService()); err != nil {
 		return nil, err
 	}
 
 	// Step 3: Validate every enum, message, and extension declaration.
 	if err := validateEnumDeclarations(f.L1.Enums.List, fd.GetEnumType()); err != nil {
 		return nil, err
 	}
 	if err := validateMessageDeclarations(f.L1.Messages.List, fd.GetMessageType()); err != nil {
 		return nil, err
 	}
 	if err := validateExtensionDeclarations(f.L1.Extensions.List, fd.GetExtension()); err != nil {
 		return nil, err
 	}
 
 	return f, nil
 }
 
 type importSet map[string]bool
 
 func (is importSet) importPublic(imps protoreflect.FileImports) {
 	for i := 0; i < imps.Len(); i++ {
 		if imp := imps.Get(i); imp.IsPublic {
 			is[imp.Path()] = true
 			is.importPublic(imp.Imports())
 		}
 	}
 }
 
 // NewFiles creates a new protoregistry.Files from the provided
 // FileDescriptorSet message. The descriptor set must include only
 // valid files according to protobuf semantics. The returned descriptors
 // are a deep copy of the input.
 func (o FileOptions) NewFiles(fds *descriptorpb.FileDescriptorSet) (*protoregistry.Files, error) {
 	files := make(map[string]*descriptorpb.FileDescriptorProto)
 	for _, fd := range fds.File {
 		if _, ok := files[fd.GetName()]; ok {
 			return nil, errors.New("file appears multiple times: %q", fd.GetName())
 		}
 		files[fd.GetName()] = fd
 	}
 	r := &protoregistry.Files{}
 	for _, fd := range files {
 		if err := o.addFileDeps(r, fd, files); err != nil {
 			return nil, err
 		}
 	}
 	return r, nil
 }
 func (o FileOptions) addFileDeps(r *protoregistry.Files, fd *descriptorpb.FileDescriptorProto, files map[string]*descriptorpb.FileDescriptorProto) error {
 	// Set the entry to nil while descending into a file's dependencies to detect cycles.
 	files[fd.GetName()] = nil
 	for _, dep := range fd.Dependency {
 		depfd, ok := files[dep]
 		if depfd == nil {
 			if ok {
 				return errors.New("import cycle in file: %q", dep)
 			}
 			continue
 		}
 		if err := o.addFileDeps(r, depfd, files); err != nil {
 			return err
 		}
 	}
 	// Delete the entry once dependencies are processed.
 	delete(files, fd.GetName())
 	f, err := o.New(fd, r)
 	if err != nil {
 		return err
 	}
 	return r.RegisterFile(f)
 }