| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.apache.wayang.core.plan.wayangplan; |
| |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.HashSet; |
| import java.util.List; |
| import org.apache.commons.lang3.Validate; |
| import org.apache.logging.log4j.LogManager; |
| import org.apache.wayang.core.util.OneTimeExecutable; |
| |
| /** |
| * Goes over a {@link WayangPlan} and isolates its loops. |
| */ |
| public class LoopIsolator extends OneTimeExecutable { |
| |
| // Refactor: We don't need the OneTimeExecutable here (as of now). |
| |
| private final WayangPlan wayangPlan; |
| |
| private LoopIsolator(WayangPlan wayangPlan) { |
| this.wayangPlan = wayangPlan; |
| } |
| |
| public static void isolateLoops(WayangPlan wayangPlan) { |
| new LoopIsolator(wayangPlan).run(); |
| } |
| |
| private void run() { |
| this.execute(); |
| } |
| |
| @Override |
| protected void doExecute() { |
| if (this.wayangPlan.isLoopsIsolated()) return; |
| @SuppressWarnings("unchecked") |
| final Collection<LoopHeadOperator> loopHeads = |
| (Collection<LoopHeadOperator>) (Collection) PlanTraversal.upstream() |
| .traverse(this.wayangPlan.getSinks()) |
| .getTraversedNodesWith(Operator::isLoopHead); |
| |
| loopHeads.forEach(LoopIsolator::isolate); |
| this.wayangPlan.setLoopsIsolated(); |
| } |
| |
| /** |
| * Isolates the loop starting at the {@code allegedLoopHead}. |
| * |
| * @return the isolated {@link LoopSubplan} or {@code null} if none could be isolated |
| */ |
| public static LoopSubplan isolate(Operator allegedLoopHead) { |
| if (!allegedLoopHead.isLoopHead()) return null; |
| LoopHeadOperator loopHead = (LoopHeadOperator) allegedLoopHead; |
| |
| // Collect the InputSlots of the loop. |
| final Collection<InputSlot<?>> bodyInputSlots = collectInboundInputs(loopHead); |
| List<InputSlot<?>> loopInputSlots = new ArrayList<>(loopHead.getLoopInitializationInputs().size() + bodyInputSlots.size()); |
| loopInputSlots.addAll(loopHead.getLoopInitializationInputs()); |
| loopInputSlots.addAll(bodyInputSlots); |
| List<OutputSlot<?>> loopOutputSlots = new ArrayList<>(loopHead.getFinalLoopOutputs()); |
| |
| // TODO In the best case, we should also do the following sanity check: Is any loop body operator reachable... |
| // ...from the loop head's final OutputSlots? That would be fatal. |
| |
| // Insert a new Subplan to delimit the loop body. |
| return LoopSubplan.wrap(loopHead, loopInputSlots, loopOutputSlots); |
| } |
| |
| /** |
| * Collect all {@link InputSlot}s in the loop body corresponding to the {@code loopHead} that are not fed by the |
| * loop itself. Also, checks various sanity aspects of the loop body. |
| */ |
| private static Collection<InputSlot<?>> collectInboundInputs(LoopHeadOperator loopHead) { |
| // Gather all Operators that are part of the loop. |
| final Collection<Operator> loopBodyOperators = PlanTraversal.downstream() |
| .traverseFocused(loopHead, loopHead.getLoopBodyOutputs()) |
| .getTraversedNodes(); |
| |
| // Collect inbound InputSlots and perform sanity checks. |
| Collection<InputSlot<?>> inboundInputSlots = new HashSet<>(); |
| for (Operator loopBodyOperator : loopBodyOperators) { |
| if (loopBodyOperator == loopHead) continue; |
| |
| // Find such InputSlots that are fed from outside of this loop. |
| final InputSlot<?>[] inputs = loopBodyOperator.getAllInputs(); |
| for (InputSlot<?> input : inputs) { |
| final OutputSlot<?> occupant = input.getOccupant(); |
| if (occupant != null && !loopBodyOperators.contains(occupant.getOwner())) { |
| inboundInputSlots.add(input); |
| } |
| } |
| |
| // Sanity check the OutputSlots. |
| Validate.isTrue(!loopBodyOperator.isSink(), "Disallowed sink %s in loop body of %s.", loopBodyOperator, loopHead); |
| } |
| |
| // Sanity-check inputs of the loopHead. |
| for (InputSlot<?> inputSlot : loopHead.getLoopBodyInputs()) { |
| Validate.notNull(inputSlot.getOccupant(), "Loop body input %s is unconnected.", inputSlot); |
| Validate.isTrue(loopBodyOperators.contains(inputSlot.getOccupant().getOwner()), |
| "Illegal input for loop head input %s.", inputSlot); |
| } |
| for (InputSlot<?> initializationInput : loopHead.getLoopInitializationInputs()) { |
| if (initializationInput.getOccupant() == null) continue; |
| Validate.isTrue(!loopBodyOperators.contains(initializationInput.getOccupant().getOwner()), |
| "Illegal input for loop head input %s.", initializationInput); |
| } |
| |
| // Sanity-check the outputs of the loopHead. |
| for (OutputSlot<?> outputSlot : loopHead.getLoopBodyOutputs()) { |
| final List<? extends InputSlot<?>> occupiedSlots = outputSlot.getOccupiedSlots(); |
| if (occupiedSlots.isEmpty()) { |
| LogManager.getLogger(LoopIsolator.class).warn("{} is not feeding any input slot.", outputSlot); |
| } |
| } |
| for (OutputSlot<?> outputSlot : loopHead.getFinalLoopOutputs()) { |
| final List<? extends InputSlot<?>> occupiedSlots = outputSlot.getOccupiedSlots(); |
| for (InputSlot<?> occupiedSlot : occupiedSlots) { |
| Validate.isTrue(!loopBodyOperators.contains(occupiedSlot.getOwner()), |
| "%s is inside and outside the loop body of %s.", occupiedSlot.getOccupant(), loopHead); |
| } |
| } |
| |
| return inboundInputSlots; |
| } |
| } |