mpagenko | af80163 | 2020-07-03 10:00:42 +0000 | [diff] [blame^] | 1 | // Copyright 2019 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 | |
| 5 | package impl |
| 6 | |
| 7 | import ( |
| 8 | "encoding/binary" |
| 9 | "encoding/json" |
| 10 | "hash/crc32" |
| 11 | "math" |
| 12 | "reflect" |
| 13 | |
| 14 | "google.golang.org/protobuf/internal/errors" |
| 15 | pref "google.golang.org/protobuf/reflect/protoreflect" |
| 16 | piface "google.golang.org/protobuf/runtime/protoiface" |
| 17 | ) |
| 18 | |
| 19 | // These functions exist to support exported APIs in generated protobufs. |
| 20 | // While these are deprecated, they cannot be removed for compatibility reasons. |
| 21 | |
| 22 | // LegacyEnumName returns the name of enums used in legacy code. |
| 23 | func (Export) LegacyEnumName(ed pref.EnumDescriptor) string { |
| 24 | return legacyEnumName(ed) |
| 25 | } |
| 26 | |
| 27 | // LegacyMessageTypeOf returns the protoreflect.MessageType for m, |
| 28 | // with name used as the message name if necessary. |
| 29 | func (Export) LegacyMessageTypeOf(m piface.MessageV1, name pref.FullName) pref.MessageType { |
| 30 | if mv := (Export{}).protoMessageV2Of(m); mv != nil { |
| 31 | return mv.ProtoReflect().Type() |
| 32 | } |
| 33 | return legacyLoadMessageInfo(reflect.TypeOf(m), name) |
| 34 | } |
| 35 | |
| 36 | // UnmarshalJSONEnum unmarshals an enum from a JSON-encoded input. |
| 37 | // The input can either be a string representing the enum value by name, |
| 38 | // or a number representing the enum number itself. |
| 39 | func (Export) UnmarshalJSONEnum(ed pref.EnumDescriptor, b []byte) (pref.EnumNumber, error) { |
| 40 | if b[0] == '"' { |
| 41 | var name pref.Name |
| 42 | if err := json.Unmarshal(b, &name); err != nil { |
| 43 | return 0, errors.New("invalid input for enum %v: %s", ed.FullName(), b) |
| 44 | } |
| 45 | ev := ed.Values().ByName(name) |
| 46 | if ev == nil { |
| 47 | return 0, errors.New("invalid value for enum %v: %s", ed.FullName(), name) |
| 48 | } |
| 49 | return ev.Number(), nil |
| 50 | } else { |
| 51 | var num pref.EnumNumber |
| 52 | if err := json.Unmarshal(b, &num); err != nil { |
| 53 | return 0, errors.New("invalid input for enum %v: %s", ed.FullName(), b) |
| 54 | } |
| 55 | return num, nil |
| 56 | } |
| 57 | } |
| 58 | |
| 59 | // CompressGZIP compresses the input as a GZIP-encoded file. |
| 60 | // The current implementation does no compression. |
| 61 | func (Export) CompressGZIP(in []byte) (out []byte) { |
| 62 | // RFC 1952, section 2.3.1. |
| 63 | var gzipHeader = [10]byte{0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff} |
| 64 | |
| 65 | // RFC 1951, section 3.2.4. |
| 66 | var blockHeader [5]byte |
| 67 | const maxBlockSize = math.MaxUint16 |
| 68 | numBlocks := 1 + len(in)/maxBlockSize |
| 69 | |
| 70 | // RFC 1952, section 2.3.1. |
| 71 | var gzipFooter [8]byte |
| 72 | binary.LittleEndian.PutUint32(gzipFooter[0:4], crc32.ChecksumIEEE(in)) |
| 73 | binary.LittleEndian.PutUint32(gzipFooter[4:8], uint32(len(in))) |
| 74 | |
| 75 | // Encode the input without compression using raw DEFLATE blocks. |
| 76 | out = make([]byte, 0, len(gzipHeader)+len(blockHeader)*numBlocks+len(in)+len(gzipFooter)) |
| 77 | out = append(out, gzipHeader[:]...) |
| 78 | for blockHeader[0] == 0 { |
| 79 | blockSize := maxBlockSize |
| 80 | if blockSize > len(in) { |
| 81 | blockHeader[0] = 0x01 // final bit per RFC 1951, section 3.2.3. |
| 82 | blockSize = len(in) |
| 83 | } |
| 84 | binary.LittleEndian.PutUint16(blockHeader[1:3], uint16(blockSize)^0x0000) |
| 85 | binary.LittleEndian.PutUint16(blockHeader[3:5], uint16(blockSize)^0xffff) |
| 86 | out = append(out, blockHeader[:]...) |
| 87 | out = append(out, in[:blockSize]...) |
| 88 | in = in[blockSize:] |
| 89 | } |
| 90 | out = append(out, gzipFooter[:]...) |
| 91 | return out |
| 92 | } |