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 5package impl 6 7import ( 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 "google.golang.org/protobuf/reflect/protoreflect" 16 "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. 22type coderMessageInfo struct { 23 methods protoiface.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 37type 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 protoreflect.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 50func (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() == protoreflect.Repeated || fd.HasPresence(), 129 isRequired: fd.Cardinality() == protoreflect.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 protoreflect.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 |= protoiface.SupportMarshalDeterministic 179 mi.methods.Marshal = mi.marshal 180 mi.methods.Size = mi.size 181 } 182 if mi.methods.Unmarshal == nil { 183 mi.methods.Flags |= protoiface.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. 197func (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. 207func (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} 218