Scott Baker | 1fe7273 | 2019-10-21 10:58:51 -0700 | [diff] [blame] | 1 | // Go support for Protocol Buffers - Google's data interchange format |
| 2 | // |
| 3 | // Copyright 2017 The Go Authors. All rights reserved. |
| 4 | // https://github.com/golang/protobuf |
| 5 | // |
| 6 | // Redistribution and use in source and binary forms, with or without |
| 7 | // modification, are permitted provided that the following conditions are |
| 8 | // met: |
| 9 | // |
| 10 | // * Redistributions of source code must retain the above copyright |
| 11 | // notice, this list of conditions and the following disclaimer. |
| 12 | // * Redistributions in binary form must reproduce the above |
| 13 | // copyright notice, this list of conditions and the following disclaimer |
| 14 | // in the documentation and/or other materials provided with the |
| 15 | // distribution. |
| 16 | // * Neither the name of Google Inc. nor the names of its |
| 17 | // contributors may be used to endorse or promote products derived from |
| 18 | // this software without specific prior written permission. |
| 19 | // |
| 20 | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 21 | // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 22 | // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 23 | // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 24 | // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 25 | // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 26 | // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 27 | // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 28 | // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 29 | // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 30 | // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 31 | |
| 32 | package proto |
| 33 | |
| 34 | import ( |
| 35 | "fmt" |
| 36 | "reflect" |
| 37 | "strings" |
| 38 | "sync" |
| 39 | "sync/atomic" |
| 40 | ) |
| 41 | |
| 42 | type generatedDiscarder interface { |
| 43 | XXX_DiscardUnknown() |
| 44 | } |
| 45 | |
| 46 | // DiscardUnknown recursively discards all unknown fields from this message |
| 47 | // and all embedded messages. |
| 48 | // |
| 49 | // When unmarshaling a message with unrecognized fields, the tags and values |
| 50 | // of such fields are preserved in the Message. This allows a later call to |
| 51 | // marshal to be able to produce a message that continues to have those |
| 52 | // unrecognized fields. To avoid this, DiscardUnknown is used to |
| 53 | // explicitly clear the unknown fields after unmarshaling. |
| 54 | // |
| 55 | // For proto2 messages, the unknown fields of message extensions are only |
| 56 | // discarded from messages that have been accessed via GetExtension. |
| 57 | func DiscardUnknown(m Message) { |
| 58 | if m, ok := m.(generatedDiscarder); ok { |
| 59 | m.XXX_DiscardUnknown() |
| 60 | return |
| 61 | } |
| 62 | // TODO: Dynamically populate a InternalMessageInfo for legacy messages, |
| 63 | // but the master branch has no implementation for InternalMessageInfo, |
| 64 | // so it would be more work to replicate that approach. |
| 65 | discardLegacy(m) |
| 66 | } |
| 67 | |
| 68 | // DiscardUnknown recursively discards all unknown fields. |
| 69 | func (a *InternalMessageInfo) DiscardUnknown(m Message) { |
| 70 | di := atomicLoadDiscardInfo(&a.discard) |
| 71 | if di == nil { |
| 72 | di = getDiscardInfo(reflect.TypeOf(m).Elem()) |
| 73 | atomicStoreDiscardInfo(&a.discard, di) |
| 74 | } |
| 75 | di.discard(toPointer(&m)) |
| 76 | } |
| 77 | |
| 78 | type discardInfo struct { |
| 79 | typ reflect.Type |
| 80 | |
| 81 | initialized int32 // 0: only typ is valid, 1: everything is valid |
| 82 | lock sync.Mutex |
| 83 | |
| 84 | fields []discardFieldInfo |
| 85 | unrecognized field |
| 86 | } |
| 87 | |
| 88 | type discardFieldInfo struct { |
| 89 | field field // Offset of field, guaranteed to be valid |
| 90 | discard func(src pointer) |
| 91 | } |
| 92 | |
| 93 | var ( |
| 94 | discardInfoMap = map[reflect.Type]*discardInfo{} |
| 95 | discardInfoLock sync.Mutex |
| 96 | ) |
| 97 | |
| 98 | func getDiscardInfo(t reflect.Type) *discardInfo { |
| 99 | discardInfoLock.Lock() |
| 100 | defer discardInfoLock.Unlock() |
| 101 | di := discardInfoMap[t] |
| 102 | if di == nil { |
| 103 | di = &discardInfo{typ: t} |
| 104 | discardInfoMap[t] = di |
| 105 | } |
| 106 | return di |
| 107 | } |
| 108 | |
| 109 | func (di *discardInfo) discard(src pointer) { |
| 110 | if src.isNil() { |
| 111 | return // Nothing to do. |
| 112 | } |
| 113 | |
| 114 | if atomic.LoadInt32(&di.initialized) == 0 { |
| 115 | di.computeDiscardInfo() |
| 116 | } |
| 117 | |
| 118 | for _, fi := range di.fields { |
| 119 | sfp := src.offset(fi.field) |
| 120 | fi.discard(sfp) |
| 121 | } |
| 122 | |
| 123 | // For proto2 messages, only discard unknown fields in message extensions |
| 124 | // that have been accessed via GetExtension. |
| 125 | if em, err := extendable(src.asPointerTo(di.typ).Interface()); err == nil { |
| 126 | // Ignore lock since DiscardUnknown is not concurrency safe. |
| 127 | emm, _ := em.extensionsRead() |
| 128 | for _, mx := range emm { |
| 129 | if m, ok := mx.value.(Message); ok { |
| 130 | DiscardUnknown(m) |
| 131 | } |
| 132 | } |
| 133 | } |
| 134 | |
| 135 | if di.unrecognized.IsValid() { |
| 136 | *src.offset(di.unrecognized).toBytes() = nil |
| 137 | } |
| 138 | } |
| 139 | |
| 140 | func (di *discardInfo) computeDiscardInfo() { |
| 141 | di.lock.Lock() |
| 142 | defer di.lock.Unlock() |
| 143 | if di.initialized != 0 { |
| 144 | return |
| 145 | } |
| 146 | t := di.typ |
| 147 | n := t.NumField() |
| 148 | |
| 149 | for i := 0; i < n; i++ { |
| 150 | f := t.Field(i) |
| 151 | if strings.HasPrefix(f.Name, "XXX_") { |
| 152 | continue |
| 153 | } |
| 154 | |
| 155 | dfi := discardFieldInfo{field: toField(&f)} |
| 156 | tf := f.Type |
| 157 | |
| 158 | // Unwrap tf to get its most basic type. |
| 159 | var isPointer, isSlice bool |
| 160 | if tf.Kind() == reflect.Slice && tf.Elem().Kind() != reflect.Uint8 { |
| 161 | isSlice = true |
| 162 | tf = tf.Elem() |
| 163 | } |
| 164 | if tf.Kind() == reflect.Ptr { |
| 165 | isPointer = true |
| 166 | tf = tf.Elem() |
| 167 | } |
| 168 | if isPointer && isSlice && tf.Kind() != reflect.Struct { |
| 169 | panic(fmt.Sprintf("%v.%s cannot be a slice of pointers to primitive types", t, f.Name)) |
| 170 | } |
| 171 | |
| 172 | switch tf.Kind() { |
| 173 | case reflect.Struct: |
| 174 | switch { |
| 175 | case !isPointer: |
| 176 | panic(fmt.Sprintf("%v.%s cannot be a direct struct value", t, f.Name)) |
| 177 | case isSlice: // E.g., []*pb.T |
| 178 | di := getDiscardInfo(tf) |
| 179 | dfi.discard = func(src pointer) { |
| 180 | sps := src.getPointerSlice() |
| 181 | for _, sp := range sps { |
| 182 | if !sp.isNil() { |
| 183 | di.discard(sp) |
| 184 | } |
| 185 | } |
| 186 | } |
| 187 | default: // E.g., *pb.T |
| 188 | di := getDiscardInfo(tf) |
| 189 | dfi.discard = func(src pointer) { |
| 190 | sp := src.getPointer() |
| 191 | if !sp.isNil() { |
| 192 | di.discard(sp) |
| 193 | } |
| 194 | } |
| 195 | } |
| 196 | case reflect.Map: |
| 197 | switch { |
| 198 | case isPointer || isSlice: |
| 199 | panic(fmt.Sprintf("%v.%s cannot be a pointer to a map or a slice of map values", t, f.Name)) |
| 200 | default: // E.g., map[K]V |
| 201 | if tf.Elem().Kind() == reflect.Ptr { // Proto struct (e.g., *T) |
| 202 | dfi.discard = func(src pointer) { |
| 203 | sm := src.asPointerTo(tf).Elem() |
| 204 | if sm.Len() == 0 { |
| 205 | return |
| 206 | } |
| 207 | for _, key := range sm.MapKeys() { |
| 208 | val := sm.MapIndex(key) |
| 209 | DiscardUnknown(val.Interface().(Message)) |
| 210 | } |
| 211 | } |
| 212 | } else { |
| 213 | dfi.discard = func(pointer) {} // Noop |
| 214 | } |
| 215 | } |
| 216 | case reflect.Interface: |
| 217 | // Must be oneof field. |
| 218 | switch { |
| 219 | case isPointer || isSlice: |
| 220 | panic(fmt.Sprintf("%v.%s cannot be a pointer to a interface or a slice of interface values", t, f.Name)) |
| 221 | default: // E.g., interface{} |
| 222 | // TODO: Make this faster? |
| 223 | dfi.discard = func(src pointer) { |
| 224 | su := src.asPointerTo(tf).Elem() |
| 225 | if !su.IsNil() { |
| 226 | sv := su.Elem().Elem().Field(0) |
| 227 | if sv.Kind() == reflect.Ptr && sv.IsNil() { |
| 228 | return |
| 229 | } |
| 230 | switch sv.Type().Kind() { |
| 231 | case reflect.Ptr: // Proto struct (e.g., *T) |
| 232 | DiscardUnknown(sv.Interface().(Message)) |
| 233 | } |
| 234 | } |
| 235 | } |
| 236 | } |
| 237 | default: |
| 238 | continue |
| 239 | } |
| 240 | di.fields = append(di.fields, dfi) |
| 241 | } |
| 242 | |
| 243 | di.unrecognized = invalidField |
| 244 | if f, ok := t.FieldByName("XXX_unrecognized"); ok { |
| 245 | if f.Type != reflect.TypeOf([]byte{}) { |
| 246 | panic("expected XXX_unrecognized to be of type []byte") |
| 247 | } |
| 248 | di.unrecognized = toField(&f) |
| 249 | } |
| 250 | |
| 251 | atomic.StoreInt32(&di.initialized, 1) |
| 252 | } |
| 253 | |
| 254 | func discardLegacy(m Message) { |
| 255 | v := reflect.ValueOf(m) |
| 256 | if v.Kind() != reflect.Ptr || v.IsNil() { |
| 257 | return |
| 258 | } |
| 259 | v = v.Elem() |
| 260 | if v.Kind() != reflect.Struct { |
| 261 | return |
| 262 | } |
| 263 | t := v.Type() |
| 264 | |
| 265 | for i := 0; i < v.NumField(); i++ { |
| 266 | f := t.Field(i) |
| 267 | if strings.HasPrefix(f.Name, "XXX_") { |
| 268 | continue |
| 269 | } |
| 270 | vf := v.Field(i) |
| 271 | tf := f.Type |
| 272 | |
| 273 | // Unwrap tf to get its most basic type. |
| 274 | var isPointer, isSlice bool |
| 275 | if tf.Kind() == reflect.Slice && tf.Elem().Kind() != reflect.Uint8 { |
| 276 | isSlice = true |
| 277 | tf = tf.Elem() |
| 278 | } |
| 279 | if tf.Kind() == reflect.Ptr { |
| 280 | isPointer = true |
| 281 | tf = tf.Elem() |
| 282 | } |
| 283 | if isPointer && isSlice && tf.Kind() != reflect.Struct { |
| 284 | panic(fmt.Sprintf("%T.%s cannot be a slice of pointers to primitive types", m, f.Name)) |
| 285 | } |
| 286 | |
| 287 | switch tf.Kind() { |
| 288 | case reflect.Struct: |
| 289 | switch { |
| 290 | case !isPointer: |
| 291 | panic(fmt.Sprintf("%T.%s cannot be a direct struct value", m, f.Name)) |
| 292 | case isSlice: // E.g., []*pb.T |
| 293 | for j := 0; j < vf.Len(); j++ { |
| 294 | discardLegacy(vf.Index(j).Interface().(Message)) |
| 295 | } |
| 296 | default: // E.g., *pb.T |
| 297 | discardLegacy(vf.Interface().(Message)) |
| 298 | } |
| 299 | case reflect.Map: |
| 300 | switch { |
| 301 | case isPointer || isSlice: |
| 302 | panic(fmt.Sprintf("%T.%s cannot be a pointer to a map or a slice of map values", m, f.Name)) |
| 303 | default: // E.g., map[K]V |
| 304 | tv := vf.Type().Elem() |
| 305 | if tv.Kind() == reflect.Ptr && tv.Implements(protoMessageType) { // Proto struct (e.g., *T) |
| 306 | for _, key := range vf.MapKeys() { |
| 307 | val := vf.MapIndex(key) |
| 308 | discardLegacy(val.Interface().(Message)) |
| 309 | } |
| 310 | } |
| 311 | } |
| 312 | case reflect.Interface: |
| 313 | // Must be oneof field. |
| 314 | switch { |
| 315 | case isPointer || isSlice: |
| 316 | panic(fmt.Sprintf("%T.%s cannot be a pointer to a interface or a slice of interface values", m, f.Name)) |
| 317 | default: // E.g., test_proto.isCommunique_Union interface |
| 318 | if !vf.IsNil() && f.Tag.Get("protobuf_oneof") != "" { |
| 319 | vf = vf.Elem() // E.g., *test_proto.Communique_Msg |
| 320 | if !vf.IsNil() { |
| 321 | vf = vf.Elem() // E.g., test_proto.Communique_Msg |
| 322 | vf = vf.Field(0) // E.g., Proto struct (e.g., *T) or primitive value |
| 323 | if vf.Kind() == reflect.Ptr { |
| 324 | discardLegacy(vf.Interface().(Message)) |
| 325 | } |
| 326 | } |
| 327 | } |
| 328 | } |
| 329 | } |
| 330 | } |
| 331 | |
| 332 | if vf := v.FieldByName("XXX_unrecognized"); vf.IsValid() { |
| 333 | if vf.Type() != reflect.TypeOf([]byte{}) { |
| 334 | panic("expected XXX_unrecognized to be of type []byte") |
| 335 | } |
| 336 | vf.Set(reflect.ValueOf([]byte(nil))) |
| 337 | } |
| 338 | |
| 339 | // For proto2 messages, only discard unknown fields in message extensions |
| 340 | // that have been accessed via GetExtension. |
| 341 | if em, err := extendable(m); err == nil { |
| 342 | // Ignore lock since discardLegacy is not concurrency safe. |
| 343 | emm, _ := em.extensionsRead() |
| 344 | for _, mx := range emm { |
| 345 | if m, ok := mx.value.(Message); ok { |
| 346 | discardLegacy(m) |
| 347 | } |
| 348 | } |
| 349 | } |
| 350 | } |