podman
1// Copyright 2018 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package impl6
7import (8"bytes"9"compress/gzip"10"io/ioutil"11"sync"12
13"google.golang.org/protobuf/internal/filedesc"14"google.golang.org/protobuf/reflect/protoreflect"15"google.golang.org/protobuf/reflect/protoregistry"16)
17
18// Every enum and message type generated by protoc-gen-go since commit 2fc053c5
19// on February 25th, 2016 has had a method to get the raw descriptor.
20// Types that were not generated by protoc-gen-go or were generated prior
21// to that version are not supported.
22//
23// The []byte returned is the encoded form of a FileDescriptorProto message
24// compressed using GZIP. The []int is the path from the top-level file
25// to the specific message or enum declaration.
26type (27enumV1 interface {28EnumDescriptor() ([]byte, []int)29}30messageV1 interface {31Descriptor() ([]byte, []int)32}33)
34
35var legacyFileDescCache sync.Map // map[*byte]protoreflect.FileDescriptor36
37// legacyLoadFileDesc unmarshals b as a compressed FileDescriptorProto message.
38//
39// This assumes that b is immutable and that b does not refer to part of a
40// concatenated series of GZIP files (which would require shenanigans that
41// rely on the concatenation properties of both protobufs and GZIP).
42// File descriptors generated by protoc-gen-go do not rely on that property.
43func legacyLoadFileDesc(b []byte) protoreflect.FileDescriptor {44// Fast-path: check whether we already have a cached file descriptor.45if fd, ok := legacyFileDescCache.Load(&b[0]); ok {46return fd.(protoreflect.FileDescriptor)47}48
49// Slow-path: decompress and unmarshal the file descriptor proto.50zr, err := gzip.NewReader(bytes.NewReader(b))51if err != nil {52panic(err)53}54b2, err := ioutil.ReadAll(zr)55if err != nil {56panic(err)57}58
59fd := filedesc.Builder{60RawDescriptor: b2,61FileRegistry: resolverOnly{protoregistry.GlobalFiles}, // do not register back to global registry62}.Build().File63if fd, ok := legacyFileDescCache.LoadOrStore(&b[0], fd); ok {64return fd.(protoreflect.FileDescriptor)65}66return fd67}
68
69type resolverOnly struct {70reg *protoregistry.Files71}
72
73func (r resolverOnly) FindFileByPath(path string) (protoreflect.FileDescriptor, error) {74return r.reg.FindFileByPath(path)75}
76func (r resolverOnly) FindDescriptorByName(name protoreflect.FullName) (protoreflect.Descriptor, error) {77return r.reg.FindDescriptorByName(name)78}
79func (resolverOnly) RegisterFile(protoreflect.FileDescriptor) error {80return nil81}
82