| 14 | |
| 15 | |
| 16 | IntersectOrExceptTransform::Status IntersectOrExceptTransform::prepare() |
| 17 | { |
| 18 | auto & output = outputs.front(); |
| 19 | |
| 20 | if (output.isFinished()) |
| 21 | { |
| 22 | for (auto & in : inputs) |
| 23 | in.close(); |
| 24 | |
| 25 | return Status::Finished; |
| 26 | } |
| 27 | |
| 28 | if (!output.canPush()) |
| 29 | { |
| 30 | for (auto & input : inputs) |
| 31 | input.setNotNeeded(); |
| 32 | |
| 33 | return Status::PortFull; |
| 34 | } |
| 35 | |
| 36 | if (current_output_chunk) |
| 37 | { |
| 38 | output.push(std::move(current_output_chunk)); |
| 39 | } |
| 40 | |
| 41 | if (!has_input) |
| 42 | { |
| 43 | while (true) |
| 44 | { |
| 45 | if (stage == Stage::ReadLeftInput) |
| 46 | { |
| 47 | auto & input = inputs.front(); |
| 48 | |
| 49 | if (input.isFinished()) |
| 50 | { |
| 51 | inputs.back().close(); |
| 52 | output.finish(); |
| 53 | return Status::Finished; |
| 54 | } |
| 55 | |
| 56 | input.setNeeded(); |
| 57 | if (!input.hasData()) |
| 58 | return Status::NeedData; |
| 59 | |
| 60 | current_input_chunk = input.pull(); |
| 61 | has_input = true; |
| 62 | break; |
| 63 | } |
| 64 | |
| 65 | if (stage == Stage::ReadRightInput) |
| 66 | { |
| 67 | auto & input = inputs.back(); |
| 68 | |
| 69 | if (input.isFinished()) |
| 70 | { |
| 71 | if (isIntersectOperator() && !has_right_input_rows) |
| 72 | { |
| 73 | inputs.front().close(); |