khenaidoo | 106c61a | 2021-08-11 18:05:46 -0400 | [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 | "fmt" |
| 9 | "reflect" |
| 10 | "sort" |
| 11 | |
| 12 | "google.golang.org/protobuf/encoding/protowire" |
| 13 | "google.golang.org/protobuf/internal/encoding/messageset" |
| 14 | "google.golang.org/protobuf/internal/order" |
| 15 | pref "google.golang.org/protobuf/reflect/protoreflect" |
| 16 | piface "google.golang.org/protobuf/runtime/protoiface" |
| 17 | ) |
| 18 | |
| 19 | // coderMessageInfo contains per-message information used by the fast-path functions. |
| 20 | // This is a different type from MessageInfo to keep MessageInfo as general-purpose as |
| 21 | // possible. |
| 22 | type coderMessageInfo struct { |
| 23 | methods piface.Methods |
| 24 | |
| 25 | orderedCoderFields []*coderFieldInfo |
| 26 | denseCoderFields []*coderFieldInfo |
| 27 | coderFields map[protowire.Number]*coderFieldInfo |
| 28 | sizecacheOffset offset |
| 29 | unknownOffset offset |
| 30 | unknownPtrKind bool |
| 31 | extensionOffset offset |
| 32 | needsInitCheck bool |
| 33 | isMessageSet bool |
| 34 | numRequiredFields uint8 |
| 35 | } |
| 36 | |
| 37 | type coderFieldInfo struct { |
| 38 | funcs pointerCoderFuncs // fast-path per-field functions |
| 39 | mi *MessageInfo // field's message |
| 40 | ft reflect.Type |
| 41 | validation validationInfo // information used by message validation |
| 42 | num pref.FieldNumber // field number |
| 43 | offset offset // struct field offset |
| 44 | wiretag uint64 // field tag (number + wire type) |
| 45 | tagsize int // size of the varint-encoded tag |
| 46 | isPointer bool // true if IsNil may be called on the struct field |
| 47 | isRequired bool // true if field is required |
| 48 | } |
| 49 | |
| 50 | func (mi *MessageInfo) makeCoderMethods(t reflect.Type, si structInfo) { |
| 51 | mi.sizecacheOffset = invalidOffset |
| 52 | mi.unknownOffset = invalidOffset |
| 53 | mi.extensionOffset = invalidOffset |
| 54 | |
| 55 | if si.sizecacheOffset.IsValid() && si.sizecacheType == sizecacheType { |
| 56 | mi.sizecacheOffset = si.sizecacheOffset |
| 57 | } |
| 58 | if si.unknownOffset.IsValid() && (si.unknownType == unknownFieldsAType || si.unknownType == unknownFieldsBType) { |
| 59 | mi.unknownOffset = si.unknownOffset |
| 60 | mi.unknownPtrKind = si.unknownType.Kind() == reflect.Ptr |
| 61 | } |
| 62 | if si.extensionOffset.IsValid() && si.extensionType == extensionFieldsType { |
| 63 | mi.extensionOffset = si.extensionOffset |
| 64 | } |
| 65 | |
| 66 | mi.coderFields = make(map[protowire.Number]*coderFieldInfo) |
| 67 | fields := mi.Desc.Fields() |
| 68 | preallocFields := make([]coderFieldInfo, fields.Len()) |
| 69 | for i := 0; i < fields.Len(); i++ { |
| 70 | fd := fields.Get(i) |
| 71 | |
| 72 | fs := si.fieldsByNumber[fd.Number()] |
| 73 | isOneof := fd.ContainingOneof() != nil && !fd.ContainingOneof().IsSynthetic() |
| 74 | if isOneof { |
| 75 | fs = si.oneofsByName[fd.ContainingOneof().Name()] |
| 76 | } |
| 77 | ft := fs.Type |
| 78 | var wiretag uint64 |
| 79 | if !fd.IsPacked() { |
| 80 | wiretag = protowire.EncodeTag(fd.Number(), wireTypes[fd.Kind()]) |
| 81 | } else { |
| 82 | wiretag = protowire.EncodeTag(fd.Number(), protowire.BytesType) |
| 83 | } |
| 84 | var fieldOffset offset |
| 85 | var funcs pointerCoderFuncs |
| 86 | var childMessage *MessageInfo |
| 87 | switch { |
| 88 | case ft == nil: |
| 89 | // This never occurs for generated message types. |
| 90 | // It implies that a hand-crafted type has missing Go fields |
| 91 | // for specific protobuf message fields. |
| 92 | funcs = pointerCoderFuncs{ |
| 93 | size: func(p pointer, f *coderFieldInfo, opts marshalOptions) int { |
| 94 | return 0 |
| 95 | }, |
| 96 | marshal: func(b []byte, p pointer, f *coderFieldInfo, opts marshalOptions) ([]byte, error) { |
| 97 | return nil, nil |
| 98 | }, |
| 99 | unmarshal: func(b []byte, p pointer, wtyp protowire.Type, f *coderFieldInfo, opts unmarshalOptions) (unmarshalOutput, error) { |
| 100 | panic("missing Go struct field for " + string(fd.FullName())) |
| 101 | }, |
| 102 | isInit: func(p pointer, f *coderFieldInfo) error { |
| 103 | panic("missing Go struct field for " + string(fd.FullName())) |
| 104 | }, |
| 105 | merge: func(dst, src pointer, f *coderFieldInfo, opts mergeOptions) { |
| 106 | panic("missing Go struct field for " + string(fd.FullName())) |
| 107 | }, |
| 108 | } |
| 109 | case isOneof: |
| 110 | fieldOffset = offsetOf(fs, mi.Exporter) |
| 111 | case fd.IsWeak(): |
| 112 | fieldOffset = si.weakOffset |
| 113 | funcs = makeWeakMessageFieldCoder(fd) |
| 114 | default: |
| 115 | fieldOffset = offsetOf(fs, mi.Exporter) |
| 116 | childMessage, funcs = fieldCoder(fd, ft) |
| 117 | } |
| 118 | cf := &preallocFields[i] |
| 119 | *cf = coderFieldInfo{ |
| 120 | num: fd.Number(), |
| 121 | offset: fieldOffset, |
| 122 | wiretag: wiretag, |
| 123 | ft: ft, |
| 124 | tagsize: protowire.SizeVarint(wiretag), |
| 125 | funcs: funcs, |
| 126 | mi: childMessage, |
| 127 | validation: newFieldValidationInfo(mi, si, fd, ft), |
| 128 | isPointer: fd.Cardinality() == pref.Repeated || fd.HasPresence(), |
| 129 | isRequired: fd.Cardinality() == pref.Required, |
| 130 | } |
| 131 | mi.orderedCoderFields = append(mi.orderedCoderFields, cf) |
| 132 | mi.coderFields[cf.num] = cf |
| 133 | } |
| 134 | for i, oneofs := 0, mi.Desc.Oneofs(); i < oneofs.Len(); i++ { |
| 135 | if od := oneofs.Get(i); !od.IsSynthetic() { |
| 136 | mi.initOneofFieldCoders(od, si) |
| 137 | } |
| 138 | } |
| 139 | if messageset.IsMessageSet(mi.Desc) { |
| 140 | if !mi.extensionOffset.IsValid() { |
| 141 | panic(fmt.Sprintf("%v: MessageSet with no extensions field", mi.Desc.FullName())) |
| 142 | } |
| 143 | if !mi.unknownOffset.IsValid() { |
| 144 | panic(fmt.Sprintf("%v: MessageSet with no unknown field", mi.Desc.FullName())) |
| 145 | } |
| 146 | mi.isMessageSet = true |
| 147 | } |
| 148 | sort.Slice(mi.orderedCoderFields, func(i, j int) bool { |
| 149 | return mi.orderedCoderFields[i].num < mi.orderedCoderFields[j].num |
| 150 | }) |
| 151 | |
| 152 | var maxDense pref.FieldNumber |
| 153 | for _, cf := range mi.orderedCoderFields { |
| 154 | if cf.num >= 16 && cf.num >= 2*maxDense { |
| 155 | break |
| 156 | } |
| 157 | maxDense = cf.num |
| 158 | } |
| 159 | mi.denseCoderFields = make([]*coderFieldInfo, maxDense+1) |
| 160 | for _, cf := range mi.orderedCoderFields { |
| 161 | if int(cf.num) >= len(mi.denseCoderFields) { |
| 162 | break |
| 163 | } |
| 164 | mi.denseCoderFields[cf.num] = cf |
| 165 | } |
| 166 | |
| 167 | // To preserve compatibility with historic wire output, marshal oneofs last. |
| 168 | if mi.Desc.Oneofs().Len() > 0 { |
| 169 | sort.Slice(mi.orderedCoderFields, func(i, j int) bool { |
| 170 | fi := fields.ByNumber(mi.orderedCoderFields[i].num) |
| 171 | fj := fields.ByNumber(mi.orderedCoderFields[j].num) |
| 172 | return order.LegacyFieldOrder(fi, fj) |
| 173 | }) |
| 174 | } |
| 175 | |
| 176 | mi.needsInitCheck = needsInitCheck(mi.Desc) |
| 177 | if mi.methods.Marshal == nil && mi.methods.Size == nil { |
| 178 | mi.methods.Flags |= piface.SupportMarshalDeterministic |
| 179 | mi.methods.Marshal = mi.marshal |
| 180 | mi.methods.Size = mi.size |
| 181 | } |
| 182 | if mi.methods.Unmarshal == nil { |
| 183 | mi.methods.Flags |= piface.SupportUnmarshalDiscardUnknown |
| 184 | mi.methods.Unmarshal = mi.unmarshal |
| 185 | } |
| 186 | if mi.methods.CheckInitialized == nil { |
| 187 | mi.methods.CheckInitialized = mi.checkInitialized |
| 188 | } |
| 189 | if mi.methods.Merge == nil { |
| 190 | mi.methods.Merge = mi.merge |
| 191 | } |
| 192 | } |
| 193 | |
| 194 | // getUnknownBytes returns a *[]byte for the unknown fields. |
| 195 | // It is the caller's responsibility to check whether the pointer is nil. |
| 196 | // This function is specially designed to be inlineable. |
| 197 | func (mi *MessageInfo) getUnknownBytes(p pointer) *[]byte { |
| 198 | if mi.unknownPtrKind { |
| 199 | return *p.Apply(mi.unknownOffset).BytesPtr() |
| 200 | } else { |
| 201 | return p.Apply(mi.unknownOffset).Bytes() |
| 202 | } |
| 203 | } |
| 204 | |
| 205 | // mutableUnknownBytes returns a *[]byte for the unknown fields. |
| 206 | // The returned pointer is guaranteed to not be nil. |
| 207 | func (mi *MessageInfo) mutableUnknownBytes(p pointer) *[]byte { |
| 208 | if mi.unknownPtrKind { |
| 209 | bp := p.Apply(mi.unknownOffset).BytesPtr() |
| 210 | if *bp == nil { |
| 211 | *bp = new([]byte) |
| 212 | } |
| 213 | return *bp |
| 214 | } else { |
| 215 | return p.Apply(mi.unknownOffset).Bytes() |
| 216 | } |
| 217 | } |