A common continuation callback for ReadMessage and ReadMessageAsync overloads
| 334 | |
| 335 | // A common continuation callback for ReadMessage and ReadMessageAsync overloads |
| 336 | static Result<std::unique_ptr<Message>> ReadMessageContinued( |
| 337 | int64_t offset, int32_t metadata_length, std::optional<int64_t> body_length, |
| 338 | std::shared_ptr<Buffer> metadata, io::RandomAccessFile* file, |
| 339 | const FieldsLoaderFunction& fields_loader, ReadMessageState* state) { |
| 340 | MessageDecoder* decoder = state->decoder.get(); |
| 341 | if (body_length.has_value()) { |
| 342 | // If body length was known, the given buffer should contain exactly the metadata |
| 343 | // followed by the body. |
| 344 | DCHECK_EQ(metadata->size(), metadata_length + *body_length); |
| 345 | } |
| 346 | ARROW_RETURN_NOT_OK(decoder->Consume(SliceBuffer(metadata, 0, metadata_length))); |
| 347 | if (decoder->buffered_size() > 0) { |
| 348 | return Status::Invalid("Message metadata too long by ", decoder->buffered_size(), |
| 349 | " bytes"); |
| 350 | } |
| 351 | switch (decoder->state()) { |
| 352 | case MessageDecoder::State::INITIAL: |
| 353 | return std::move(state->result); |
| 354 | case MessageDecoder::State::METADATA_LENGTH: |
| 355 | return Status::Invalid("metadata length is missing. File offset: ", offset, |
| 356 | ", metadata length: ", metadata_length); |
| 357 | case MessageDecoder::State::METADATA: |
| 358 | return Status::Invalid("flatbuffer size ", decoder->next_required_size(), |
| 359 | " invalid. File offset: ", offset, |
| 360 | ", metadata length: ", metadata_length); |
| 361 | case MessageDecoder::State::BODY: { |
| 362 | std::shared_ptr<Buffer> body; |
| 363 | if (fields_loader) { |
| 364 | // Selective field loading: allocate a body buffer and read only the |
| 365 | // requested field ranges into it. |
| 366 | DCHECK_NE(file, nullptr); |
| 367 | ARROW_ASSIGN_OR_RAISE( |
| 368 | body, AllocateBuffer(decoder->next_required_size(), default_memory_pool())); |
| 369 | RETURN_NOT_OK(ReadFieldsSubset(offset, file, fields_loader, |
| 370 | SliceBuffer(metadata, 0, metadata_length), |
| 371 | decoder->next_required_size(), body)); |
| 372 | } else if (body_length.has_value()) { |
| 373 | // Body was already read as part of the combined IO; just slice it out. |
| 374 | if (*body_length != decoder->next_required_size()) { |
| 375 | // The streaming decoder got out of sync with the actual advertised |
| 376 | // metadata and body size, which signals an invalid IPC file. |
| 377 | return Status::IOError("Invalid IPC file: advertised body size is ", |
| 378 | *body_length, ", but message decoder expects to read ", |
| 379 | decoder->next_required_size(), " bytes instead"); |
| 380 | } |
| 381 | body = SliceBuffer(metadata, metadata_length, |
| 382 | std::min(*body_length, metadata->size() - metadata_length)); |
| 383 | } else { |
| 384 | // Body length was unknown; do a separate IO to read the body. |
| 385 | DCHECK_NE(file, nullptr); |
| 386 | ARROW_ASSIGN_OR_RAISE( |
| 387 | body, file->ReadAt(offset + metadata_length, decoder->next_required_size(), |
| 388 | /*allow_short_read=*/false)); |
| 389 | } |
| 390 | |
| 391 | RETURN_NOT_OK(decoder->Consume(body)); |
| 392 | return std::move(state->result); |
| 393 | } |
no test coverage detected