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 2010 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 | /* |
| 35 | * Routines for decoding protocol buffer data to construct in-memory representations. |
| 36 | */ |
| 37 | |
| 38 | import ( |
| 39 | "errors" |
| 40 | "fmt" |
| 41 | "io" |
| 42 | ) |
| 43 | |
| 44 | // errOverflow is returned when an integer is too large to be represented. |
| 45 | var errOverflow = errors.New("proto: integer overflow") |
| 46 | |
| 47 | // ErrInternalBadWireType is returned by generated code when an incorrect |
| 48 | // wire type is encountered. It does not get returned to user code. |
| 49 | var ErrInternalBadWireType = errors.New("proto: internal error: bad wiretype for oneof") |
| 50 | |
| 51 | // DecodeVarint reads a varint-encoded integer from the slice. |
| 52 | // It returns the integer and the number of bytes consumed, or |
| 53 | // zero if there is not enough. |
| 54 | // This is the format for the |
| 55 | // int32, int64, uint32, uint64, bool, and enum |
| 56 | // protocol buffer types. |
| 57 | func DecodeVarint(buf []byte) (x uint64, n int) { |
| 58 | for shift := uint(0); shift < 64; shift += 7 { |
| 59 | if n >= len(buf) { |
| 60 | return 0, 0 |
| 61 | } |
| 62 | b := uint64(buf[n]) |
| 63 | n++ |
| 64 | x |= (b & 0x7F) << shift |
| 65 | if (b & 0x80) == 0 { |
| 66 | return x, n |
| 67 | } |
| 68 | } |
| 69 | |
| 70 | // The number is too large to represent in a 64-bit value. |
| 71 | return 0, 0 |
| 72 | } |
| 73 | |
| 74 | func (p *Buffer) decodeVarintSlow() (x uint64, err error) { |
| 75 | i := p.index |
| 76 | l := len(p.buf) |
| 77 | |
| 78 | for shift := uint(0); shift < 64; shift += 7 { |
| 79 | if i >= l { |
| 80 | err = io.ErrUnexpectedEOF |
| 81 | return |
| 82 | } |
| 83 | b := p.buf[i] |
| 84 | i++ |
| 85 | x |= (uint64(b) & 0x7F) << shift |
| 86 | if b < 0x80 { |
| 87 | p.index = i |
| 88 | return |
| 89 | } |
| 90 | } |
| 91 | |
| 92 | // The number is too large to represent in a 64-bit value. |
| 93 | err = errOverflow |
| 94 | return |
| 95 | } |
| 96 | |
| 97 | // DecodeVarint reads a varint-encoded integer from the Buffer. |
| 98 | // This is the format for the |
| 99 | // int32, int64, uint32, uint64, bool, and enum |
| 100 | // protocol buffer types. |
| 101 | func (p *Buffer) DecodeVarint() (x uint64, err error) { |
| 102 | i := p.index |
| 103 | buf := p.buf |
| 104 | |
| 105 | if i >= len(buf) { |
| 106 | return 0, io.ErrUnexpectedEOF |
| 107 | } else if buf[i] < 0x80 { |
| 108 | p.index++ |
| 109 | return uint64(buf[i]), nil |
| 110 | } else if len(buf)-i < 10 { |
| 111 | return p.decodeVarintSlow() |
| 112 | } |
| 113 | |
| 114 | var b uint64 |
| 115 | // we already checked the first byte |
| 116 | x = uint64(buf[i]) - 0x80 |
| 117 | i++ |
| 118 | |
| 119 | b = uint64(buf[i]) |
| 120 | i++ |
| 121 | x += b << 7 |
| 122 | if b&0x80 == 0 { |
| 123 | goto done |
| 124 | } |
| 125 | x -= 0x80 << 7 |
| 126 | |
| 127 | b = uint64(buf[i]) |
| 128 | i++ |
| 129 | x += b << 14 |
| 130 | if b&0x80 == 0 { |
| 131 | goto done |
| 132 | } |
| 133 | x -= 0x80 << 14 |
| 134 | |
| 135 | b = uint64(buf[i]) |
| 136 | i++ |
| 137 | x += b << 21 |
| 138 | if b&0x80 == 0 { |
| 139 | goto done |
| 140 | } |
| 141 | x -= 0x80 << 21 |
| 142 | |
| 143 | b = uint64(buf[i]) |
| 144 | i++ |
| 145 | x += b << 28 |
| 146 | if b&0x80 == 0 { |
| 147 | goto done |
| 148 | } |
| 149 | x -= 0x80 << 28 |
| 150 | |
| 151 | b = uint64(buf[i]) |
| 152 | i++ |
| 153 | x += b << 35 |
| 154 | if b&0x80 == 0 { |
| 155 | goto done |
| 156 | } |
| 157 | x -= 0x80 << 35 |
| 158 | |
| 159 | b = uint64(buf[i]) |
| 160 | i++ |
| 161 | x += b << 42 |
| 162 | if b&0x80 == 0 { |
| 163 | goto done |
| 164 | } |
| 165 | x -= 0x80 << 42 |
| 166 | |
| 167 | b = uint64(buf[i]) |
| 168 | i++ |
| 169 | x += b << 49 |
| 170 | if b&0x80 == 0 { |
| 171 | goto done |
| 172 | } |
| 173 | x -= 0x80 << 49 |
| 174 | |
| 175 | b = uint64(buf[i]) |
| 176 | i++ |
| 177 | x += b << 56 |
| 178 | if b&0x80 == 0 { |
| 179 | goto done |
| 180 | } |
| 181 | x -= 0x80 << 56 |
| 182 | |
| 183 | b = uint64(buf[i]) |
| 184 | i++ |
| 185 | x += b << 63 |
| 186 | if b&0x80 == 0 { |
| 187 | goto done |
| 188 | } |
| 189 | |
| 190 | return 0, errOverflow |
| 191 | |
| 192 | done: |
| 193 | p.index = i |
| 194 | return x, nil |
| 195 | } |
| 196 | |
| 197 | // DecodeFixed64 reads a 64-bit integer from the Buffer. |
| 198 | // This is the format for the |
| 199 | // fixed64, sfixed64, and double protocol buffer types. |
| 200 | func (p *Buffer) DecodeFixed64() (x uint64, err error) { |
| 201 | // x, err already 0 |
| 202 | i := p.index + 8 |
| 203 | if i < 0 || i > len(p.buf) { |
| 204 | err = io.ErrUnexpectedEOF |
| 205 | return |
| 206 | } |
| 207 | p.index = i |
| 208 | |
| 209 | x = uint64(p.buf[i-8]) |
| 210 | x |= uint64(p.buf[i-7]) << 8 |
| 211 | x |= uint64(p.buf[i-6]) << 16 |
| 212 | x |= uint64(p.buf[i-5]) << 24 |
| 213 | x |= uint64(p.buf[i-4]) << 32 |
| 214 | x |= uint64(p.buf[i-3]) << 40 |
| 215 | x |= uint64(p.buf[i-2]) << 48 |
| 216 | x |= uint64(p.buf[i-1]) << 56 |
| 217 | return |
| 218 | } |
| 219 | |
| 220 | // DecodeFixed32 reads a 32-bit integer from the Buffer. |
| 221 | // This is the format for the |
| 222 | // fixed32, sfixed32, and float protocol buffer types. |
| 223 | func (p *Buffer) DecodeFixed32() (x uint64, err error) { |
| 224 | // x, err already 0 |
| 225 | i := p.index + 4 |
| 226 | if i < 0 || i > len(p.buf) { |
| 227 | err = io.ErrUnexpectedEOF |
| 228 | return |
| 229 | } |
| 230 | p.index = i |
| 231 | |
| 232 | x = uint64(p.buf[i-4]) |
| 233 | x |= uint64(p.buf[i-3]) << 8 |
| 234 | x |= uint64(p.buf[i-2]) << 16 |
| 235 | x |= uint64(p.buf[i-1]) << 24 |
| 236 | return |
| 237 | } |
| 238 | |
| 239 | // DecodeZigzag64 reads a zigzag-encoded 64-bit integer |
| 240 | // from the Buffer. |
| 241 | // This is the format used for the sint64 protocol buffer type. |
| 242 | func (p *Buffer) DecodeZigzag64() (x uint64, err error) { |
| 243 | x, err = p.DecodeVarint() |
| 244 | if err != nil { |
| 245 | return |
| 246 | } |
| 247 | x = (x >> 1) ^ uint64((int64(x&1)<<63)>>63) |
| 248 | return |
| 249 | } |
| 250 | |
| 251 | // DecodeZigzag32 reads a zigzag-encoded 32-bit integer |
| 252 | // from the Buffer. |
| 253 | // This is the format used for the sint32 protocol buffer type. |
| 254 | func (p *Buffer) DecodeZigzag32() (x uint64, err error) { |
| 255 | x, err = p.DecodeVarint() |
| 256 | if err != nil { |
| 257 | return |
| 258 | } |
| 259 | x = uint64((uint32(x) >> 1) ^ uint32((int32(x&1)<<31)>>31)) |
| 260 | return |
| 261 | } |
| 262 | |
| 263 | // DecodeRawBytes reads a count-delimited byte buffer from the Buffer. |
| 264 | // This is the format used for the bytes protocol buffer |
| 265 | // type and for embedded messages. |
| 266 | func (p *Buffer) DecodeRawBytes(alloc bool) (buf []byte, err error) { |
| 267 | n, err := p.DecodeVarint() |
| 268 | if err != nil { |
| 269 | return nil, err |
| 270 | } |
| 271 | |
| 272 | nb := int(n) |
| 273 | if nb < 0 { |
| 274 | return nil, fmt.Errorf("proto: bad byte length %d", nb) |
| 275 | } |
| 276 | end := p.index + nb |
| 277 | if end < p.index || end > len(p.buf) { |
| 278 | return nil, io.ErrUnexpectedEOF |
| 279 | } |
| 280 | |
| 281 | if !alloc { |
| 282 | // todo: check if can get more uses of alloc=false |
| 283 | buf = p.buf[p.index:end] |
| 284 | p.index += nb |
| 285 | return |
| 286 | } |
| 287 | |
| 288 | buf = make([]byte, nb) |
| 289 | copy(buf, p.buf[p.index:]) |
| 290 | p.index += nb |
| 291 | return |
| 292 | } |
| 293 | |
| 294 | // DecodeStringBytes reads an encoded string from the Buffer. |
| 295 | // This is the format used for the proto2 string type. |
| 296 | func (p *Buffer) DecodeStringBytes() (s string, err error) { |
| 297 | buf, err := p.DecodeRawBytes(false) |
| 298 | if err != nil { |
| 299 | return |
| 300 | } |
| 301 | return string(buf), nil |
| 302 | } |
| 303 | |
| 304 | // Unmarshaler is the interface representing objects that can |
| 305 | // unmarshal themselves. The argument points to data that may be |
| 306 | // overwritten, so implementations should not keep references to the |
| 307 | // buffer. |
| 308 | // Unmarshal implementations should not clear the receiver. |
| 309 | // Any unmarshaled data should be merged into the receiver. |
| 310 | // Callers of Unmarshal that do not want to retain existing data |
| 311 | // should Reset the receiver before calling Unmarshal. |
| 312 | type Unmarshaler interface { |
| 313 | Unmarshal([]byte) error |
| 314 | } |
| 315 | |
| 316 | // newUnmarshaler is the interface representing objects that can |
| 317 | // unmarshal themselves. The semantics are identical to Unmarshaler. |
| 318 | // |
| 319 | // This exists to support protoc-gen-go generated messages. |
| 320 | // The proto package will stop type-asserting to this interface in the future. |
| 321 | // |
| 322 | // DO NOT DEPEND ON THIS. |
| 323 | type newUnmarshaler interface { |
| 324 | XXX_Unmarshal([]byte) error |
| 325 | } |
| 326 | |
| 327 | // Unmarshal parses the protocol buffer representation in buf and places the |
| 328 | // decoded result in pb. If the struct underlying pb does not match |
| 329 | // the data in buf, the results can be unpredictable. |
| 330 | // |
| 331 | // Unmarshal resets pb before starting to unmarshal, so any |
| 332 | // existing data in pb is always removed. Use UnmarshalMerge |
| 333 | // to preserve and append to existing data. |
| 334 | func Unmarshal(buf []byte, pb Message) error { |
| 335 | pb.Reset() |
| 336 | if u, ok := pb.(newUnmarshaler); ok { |
| 337 | return u.XXX_Unmarshal(buf) |
| 338 | } |
| 339 | if u, ok := pb.(Unmarshaler); ok { |
| 340 | return u.Unmarshal(buf) |
| 341 | } |
| 342 | return NewBuffer(buf).Unmarshal(pb) |
| 343 | } |
| 344 | |
| 345 | // UnmarshalMerge parses the protocol buffer representation in buf and |
| 346 | // writes the decoded result to pb. If the struct underlying pb does not match |
| 347 | // the data in buf, the results can be unpredictable. |
| 348 | // |
| 349 | // UnmarshalMerge merges into existing data in pb. |
| 350 | // Most code should use Unmarshal instead. |
| 351 | func UnmarshalMerge(buf []byte, pb Message) error { |
| 352 | if u, ok := pb.(newUnmarshaler); ok { |
| 353 | return u.XXX_Unmarshal(buf) |
| 354 | } |
| 355 | if u, ok := pb.(Unmarshaler); ok { |
| 356 | // NOTE: The history of proto have unfortunately been inconsistent |
| 357 | // whether Unmarshaler should or should not implicitly clear itself. |
| 358 | // Some implementations do, most do not. |
| 359 | // Thus, calling this here may or may not do what people want. |
| 360 | // |
| 361 | // See https://github.com/golang/protobuf/issues/424 |
| 362 | return u.Unmarshal(buf) |
| 363 | } |
| 364 | return NewBuffer(buf).Unmarshal(pb) |
| 365 | } |
| 366 | |
| 367 | // DecodeMessage reads a count-delimited message from the Buffer. |
| 368 | func (p *Buffer) DecodeMessage(pb Message) error { |
| 369 | enc, err := p.DecodeRawBytes(false) |
| 370 | if err != nil { |
| 371 | return err |
| 372 | } |
| 373 | return NewBuffer(enc).Unmarshal(pb) |
| 374 | } |
| 375 | |
| 376 | // DecodeGroup reads a tag-delimited group from the Buffer. |
| 377 | // StartGroup tag is already consumed. This function consumes |
| 378 | // EndGroup tag. |
| 379 | func (p *Buffer) DecodeGroup(pb Message) error { |
| 380 | b := p.buf[p.index:] |
| 381 | x, y := findEndGroup(b) |
| 382 | if x < 0 { |
| 383 | return io.ErrUnexpectedEOF |
| 384 | } |
| 385 | err := Unmarshal(b[:x], pb) |
| 386 | p.index += y |
| 387 | return err |
| 388 | } |
| 389 | |
| 390 | // Unmarshal parses the protocol buffer representation in the |
| 391 | // Buffer and places the decoded result in pb. If the struct |
| 392 | // underlying pb does not match the data in the buffer, the results can be |
| 393 | // unpredictable. |
| 394 | // |
| 395 | // Unlike proto.Unmarshal, this does not reset pb before starting to unmarshal. |
| 396 | func (p *Buffer) Unmarshal(pb Message) error { |
| 397 | // If the object can unmarshal itself, let it. |
| 398 | if u, ok := pb.(newUnmarshaler); ok { |
| 399 | err := u.XXX_Unmarshal(p.buf[p.index:]) |
| 400 | p.index = len(p.buf) |
| 401 | return err |
| 402 | } |
| 403 | if u, ok := pb.(Unmarshaler); ok { |
| 404 | // NOTE: The history of proto have unfortunately been inconsistent |
| 405 | // whether Unmarshaler should or should not implicitly clear itself. |
| 406 | // Some implementations do, most do not. |
| 407 | // Thus, calling this here may or may not do what people want. |
| 408 | // |
| 409 | // See https://github.com/golang/protobuf/issues/424 |
| 410 | err := u.Unmarshal(p.buf[p.index:]) |
| 411 | p.index = len(p.buf) |
| 412 | return err |
| 413 | } |
| 414 | |
| 415 | // Slow workaround for messages that aren't Unmarshalers. |
| 416 | // This includes some hand-coded .pb.go files and |
| 417 | // bootstrap protos. |
| 418 | // TODO: fix all of those and then add Unmarshal to |
| 419 | // the Message interface. Then: |
| 420 | // The cast above and code below can be deleted. |
| 421 | // The old unmarshaler can be deleted. |
| 422 | // Clients can call Unmarshal directly (can already do that, actually). |
| 423 | var info InternalMessageInfo |
| 424 | err := info.Unmarshal(pb, p.buf[p.index:]) |
| 425 | p.index = len(p.buf) |
| 426 | return err |
| 427 | } |