Naveen Sampath | 04696f7 | 2022-06-13 15:19:14 +0530 | [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 filedesc provides functionality for constructing descriptors. |
| 6 | // |
| 7 | // The types in this package implement interfaces in the protoreflect package |
| 8 | // related to protobuf descripriptors. |
| 9 | package filedesc |
| 10 | |
| 11 | import ( |
| 12 | "google.golang.org/protobuf/encoding/protowire" |
| 13 | "google.golang.org/protobuf/internal/genid" |
| 14 | "google.golang.org/protobuf/reflect/protoreflect" |
| 15 | pref "google.golang.org/protobuf/reflect/protoreflect" |
| 16 | preg "google.golang.org/protobuf/reflect/protoregistry" |
| 17 | ) |
| 18 | |
| 19 | // Builder construct a protoreflect.FileDescriptor from the raw descriptor. |
| 20 | type Builder struct { |
| 21 | // GoPackagePath is the Go package path that is invoking this builder. |
| 22 | GoPackagePath string |
| 23 | |
| 24 | // RawDescriptor is the wire-encoded bytes of FileDescriptorProto |
| 25 | // and must be populated. |
| 26 | RawDescriptor []byte |
| 27 | |
| 28 | // NumEnums is the total number of enums declared in the file. |
| 29 | NumEnums int32 |
| 30 | // NumMessages is the total number of messages declared in the file. |
| 31 | // It includes the implicit message declarations for map entries. |
| 32 | NumMessages int32 |
| 33 | // NumExtensions is the total number of extensions declared in the file. |
| 34 | NumExtensions int32 |
| 35 | // NumServices is the total number of services declared in the file. |
| 36 | NumServices int32 |
| 37 | |
| 38 | // TypeResolver resolves extension field types for descriptor options. |
| 39 | // If nil, it uses protoregistry.GlobalTypes. |
| 40 | TypeResolver interface { |
| 41 | preg.ExtensionTypeResolver |
| 42 | } |
| 43 | |
| 44 | // FileRegistry is use to lookup file, enum, and message dependencies. |
| 45 | // Once constructed, the file descriptor is registered here. |
| 46 | // If nil, it uses protoregistry.GlobalFiles. |
| 47 | FileRegistry interface { |
| 48 | FindFileByPath(string) (protoreflect.FileDescriptor, error) |
| 49 | FindDescriptorByName(pref.FullName) (pref.Descriptor, error) |
| 50 | RegisterFile(pref.FileDescriptor) error |
| 51 | } |
| 52 | } |
| 53 | |
| 54 | // resolverByIndex is an interface Builder.FileRegistry may implement. |
| 55 | // If so, it permits looking up an enum or message dependency based on the |
| 56 | // sub-list and element index into filetype.Builder.DependencyIndexes. |
| 57 | type resolverByIndex interface { |
| 58 | FindEnumByIndex(int32, int32, []Enum, []Message) pref.EnumDescriptor |
| 59 | FindMessageByIndex(int32, int32, []Enum, []Message) pref.MessageDescriptor |
| 60 | } |
| 61 | |
| 62 | // Indexes of each sub-list in filetype.Builder.DependencyIndexes. |
| 63 | const ( |
| 64 | listFieldDeps int32 = iota |
| 65 | listExtTargets |
| 66 | listExtDeps |
| 67 | listMethInDeps |
| 68 | listMethOutDeps |
| 69 | ) |
| 70 | |
| 71 | // Out is the output of the Builder. |
| 72 | type Out struct { |
| 73 | File pref.FileDescriptor |
| 74 | |
| 75 | // Enums is all enum descriptors in "flattened ordering". |
| 76 | Enums []Enum |
| 77 | // Messages is all message descriptors in "flattened ordering". |
| 78 | // It includes the implicit message declarations for map entries. |
| 79 | Messages []Message |
| 80 | // Extensions is all extension descriptors in "flattened ordering". |
| 81 | Extensions []Extension |
| 82 | // Service is all service descriptors in "flattened ordering". |
| 83 | Services []Service |
| 84 | } |
| 85 | |
| 86 | // Build constructs a FileDescriptor given the parameters set in Builder. |
| 87 | // It assumes that the inputs are well-formed and panics if any inconsistencies |
| 88 | // are encountered. |
| 89 | // |
| 90 | // If NumEnums+NumMessages+NumExtensions+NumServices is zero, |
| 91 | // then Build automatically derives them from the raw descriptor. |
| 92 | func (db Builder) Build() (out Out) { |
| 93 | // Populate the counts if uninitialized. |
| 94 | if db.NumEnums+db.NumMessages+db.NumExtensions+db.NumServices == 0 { |
| 95 | db.unmarshalCounts(db.RawDescriptor, true) |
| 96 | } |
| 97 | |
| 98 | // Initialize resolvers and registries if unpopulated. |
| 99 | if db.TypeResolver == nil { |
| 100 | db.TypeResolver = preg.GlobalTypes |
| 101 | } |
| 102 | if db.FileRegistry == nil { |
| 103 | db.FileRegistry = preg.GlobalFiles |
| 104 | } |
| 105 | |
| 106 | fd := newRawFile(db) |
| 107 | out.File = fd |
| 108 | out.Enums = fd.allEnums |
| 109 | out.Messages = fd.allMessages |
| 110 | out.Extensions = fd.allExtensions |
| 111 | out.Services = fd.allServices |
| 112 | |
| 113 | if err := db.FileRegistry.RegisterFile(fd); err != nil { |
| 114 | panic(err) |
| 115 | } |
| 116 | return out |
| 117 | } |
| 118 | |
| 119 | // unmarshalCounts counts the number of enum, message, extension, and service |
| 120 | // declarations in the raw message, which is either a FileDescriptorProto |
| 121 | // or a MessageDescriptorProto depending on whether isFile is set. |
| 122 | func (db *Builder) unmarshalCounts(b []byte, isFile bool) { |
| 123 | for len(b) > 0 { |
| 124 | num, typ, n := protowire.ConsumeTag(b) |
| 125 | b = b[n:] |
| 126 | switch typ { |
| 127 | case protowire.BytesType: |
| 128 | v, m := protowire.ConsumeBytes(b) |
| 129 | b = b[m:] |
| 130 | if isFile { |
| 131 | switch num { |
| 132 | case genid.FileDescriptorProto_EnumType_field_number: |
| 133 | db.NumEnums++ |
| 134 | case genid.FileDescriptorProto_MessageType_field_number: |
| 135 | db.unmarshalCounts(v, false) |
| 136 | db.NumMessages++ |
| 137 | case genid.FileDescriptorProto_Extension_field_number: |
| 138 | db.NumExtensions++ |
| 139 | case genid.FileDescriptorProto_Service_field_number: |
| 140 | db.NumServices++ |
| 141 | } |
| 142 | } else { |
| 143 | switch num { |
| 144 | case genid.DescriptorProto_EnumType_field_number: |
| 145 | db.NumEnums++ |
| 146 | case genid.DescriptorProto_NestedType_field_number: |
| 147 | db.unmarshalCounts(v, false) |
| 148 | db.NumMessages++ |
| 149 | case genid.DescriptorProto_Extension_field_number: |
| 150 | db.NumExtensions++ |
| 151 | } |
| 152 | } |
| 153 | default: |
| 154 | m := protowire.ConsumeFieldValue(num, typ, b) |
| 155 | b = b[m:] |
| 156 | } |
| 157 | } |
| 158 | } |