Method BlockReader

tensorflow/core/lib/io/table.cc:94–122

Convert an index iterator value (i.e., an encoded BlockHandle) into an iterator over the contents of the corresponding block.

// Convert an index iterator value (i.e., an encoded BlockHandle)
// into an iterator over the contents of the corresponding block.
Iterator* Table::BlockReader(void* arg, const StringPiece& index_value) {
  Table* table = reinterpret_cast<Table*>(arg);
  //  Cache* block_cache = table->rep_->options.block_cache;
  Block* block = nullptr;
  //  Cache::Handle* cache_handle = NULL;

  BlockHandle handle;
  StringPiece input = index_value;
  Status s = handle.DecodeFrom(&input);
  // We intentionally allow extra stuff in index_value so that we
  // can add more features in the future.

  if (s.ok()) {
    BlockContents contents;
    s = ReadBlock(table->rep_->file, handle, &contents);
    if (s.ok()) {
      block = new Block(contents);
    }
  }

  Iterator* iter;
  if (block != nullptr) {
    iter = block->NewIterator();
    iter->RegisterCleanup(&DeleteBlock, block, nullptr);
  } else {
    iter = NewErrorIterator(s);
  }
  return iter;
}

Iterator* Table::NewIterator() const {
  return NewTwoLevelIterator(rep_->index_block->NewIterator(),