feat: introduce task cancelling

src/main/java/de/dhbwstuttgart/typeinference/unify/CancellableTask.java

@@ -0,0 +1,62 @@
+package de.dhbwstuttgart.typeinference.unify;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.ConcurrentLinkedQueue;
+import java.util.concurrent.RecursiveTask;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+/**
+ * An intermediate class for the recursive steps of the TypeUnifyTask:
+ * This allows to cancel parts of the recursion tree, instead of only  the whole execution as before. But in
+ * order for that to work, all cancellable child tasks must be added when they are created
+ *
+ * @param <T>
+ */
+public abstract class CancellableTask<T> extends RecursiveTask<T> {
+
+  private final AtomicBoolean executionCancelled = new AtomicBoolean(false);
+  private final List<CancellableTask<?>> childTasks = new ArrayList<>();
+  private CancellableTask<?> parentTask = null;
+
+  /**
+   * Set the execution for this task and all its (recursive) children to be cancelled
+   */
+  protected void cancelExecution() {
+    // is this branch already cancelled? Then do nothing
+    if (this.executionCancelled.get()) return;
+    executionCancelled.set(true);
+    this.cancelChildExecution();
+  }
+
+  public void cancelChildExecution() {
+    for (var childTask : childTasks) {
+      // no need to cancel a branch that is already finished
+      if (!childTask.isDone()) {
+        childTask.cancelExecution();
+      }
+    }
+  }
+
+  protected void cancelSiblingTasks() {
+    if (this.parentTask != null) {
+      boolean thisWasCancelledBefore = this.executionCancelled.get();
+      this.parentTask.cancelChildExecution();
+      this.executionCancelled.set(thisWasCancelledBefore);
+    }
+  }
+
+  public Boolean isExecutionCancelled() {
+    return executionCancelled.get();
+  }
+
+  public void addChildTask(CancellableTask<?> childTask) {
+    this.childTasks.add(childTask);
+    childTask.setParentTask(this);
+  }
+
+  private void setParentTask(CancellableTask<?> parentTask) {
+    this.parentTask = parentTask;
+  }
+
+}

src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java

@@ -59,7 +59,7 @@ import org.apache.commons.io.output.NullOutputStream;
  *
  * @author Florian Steurer
  */
-public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<UnifyPair>>>> {
+public class TypeUnifyTask extends CancellableTask<CompletableFuture<Set<Set<UnifyPair>>>> {
 
   @Serial
   private static final long serialVersionUID = 1L;
@@ -852,6 +852,11 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
 
       if (parallel) {
         for (Set<Set<UnifyPair>> par_res : forkResults) {
+          if (variance == 0 && (!result.isEmpty() && (!isUndefinedPairSetSet(currentThreadResult)))) {
+            this.cancelChildExecution();
+            return CompletableFuture.completedFuture(result);
+          }
+
           if (!isUndefinedPairSetSet(par_res) && isUndefinedPairSetSet(result)) {
             //wenn korrektes Ergebnis gefunden alle Fehlerfaelle loeschen
             result = par_res;
@@ -884,6 +889,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
         // Iterator<Set<UnifyPair>> nextSetasListIt = new ArrayList<>(nextSetAsList).iterator();
         boolean shouldBreak = varianceCase.eraseInvalidSets(rekTiefe, aParDef, nextSetAsList);
         if (shouldBreak) {
+          this.cancelChildExecution();
           return CompletableFuture.completedFuture(result);
         }
 

src/main/java/de/dhbwstuttgart/typeinference/unify/cartesianproduct/Variance0Case.java

@@ -1,6 +1,8 @@
 package de.dhbwstuttgart.typeinference.unify.cartesianproduct;
 
+import de.dhbwstuttgart.exceptions.UnifyCancelException;
 import de.dhbwstuttgart.typeinference.constraints.Constraint;
+import de.dhbwstuttgart.typeinference.unify.TypeUnify2Task;
 import de.dhbwstuttgart.typeinference.unify.TypeUnifyTask;
 import de.dhbwstuttgart.typeinference.unify.UnifyContext;
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
@@ -9,6 +11,7 @@ import de.dhbwstuttgart.typeinference.unify.model.UnifyPair;
 import de.dhbwstuttgart.util.Tuple;
 import java.util.ArrayList;
 import java.util.HashSet;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Optional;
 import java.util.Set;
@@ -47,6 +50,29 @@ public class Variance0Case extends VarianceCase {
     } else {
       a = nextSetAsList.removeFirst();
     }
+
+
+    Set<UnifyPair> finalA = a;
+    if (!this.isOderConstraint && optOrigPair != null && optOrigPair.isPresent()) {
+      if (optOrigPair.get().getBasePair().getLhsType() instanceof PlaceholderType) {
+        nextSetasListRest = typeUnifyTask.oup.maxElements(
+          nextSetAsList.stream().filter(a_next -> typeUnifyTask.oup.compare(finalA, a_next) != 1).toList()
+        );
+      } else {
+        nextSetasListRest = typeUnifyTask.oup.minElements(
+          nextSetAsList.stream().filter(a_next -> typeUnifyTask.oup.compare(finalA, a_next) != -1).toList()
+        );
+      }
+      nextSetAsList.remove(a);
+    } else if (this.isOderConstraint) {
+      nextSetasListRest = typeUnifyTask.oup.maxElements(
+        nextSetAsList.stream().filter(a_next -> typeUnifyTask.oup.compare(finalA, a_next) != 1).toList()
+      );
+    } else {
+      for (int i = 0; i < Math.min(nextSetAsList.size(), 5); i++) {
+        nextSetasListRest.add(nextSetAsList.removeFirst());
+      }
+    }
   }
 
   @Override
@@ -62,10 +88,81 @@ public class Variance0Case extends VarianceCase {
     Set<Set<UnifyPair>> result,
     Set<Set<UnifyPair>> aParDef
   ) {
-    elems.add(a); //PL 2019-01-16 muss das wirklich hin steht schon in Zeile 859 ja braucht man siehe Zeile 859
-    return typeUnifyTask.unify2(elems, eq, oderConstraints, fc, context.parallel(), rekTiefe, new HashSet<>(methodSignatureConstraint)).thenApply(
-      unify2Result -> new Tuple<>(unify2Result, new HashSet<>())
-    );
+    CompletableFuture<Tuple<Set<Set<UnifyPair>>, Set<Set<Set<UnifyPair>>>>> resultValues = CompletableFuture.completedFuture(new Tuple<>(
+      new HashSet<>(), new HashSet<>()
+    ));
+
+    Set<UnifyPair> newEqOrig = new HashSet<>(eq);
+    Set<Set<UnifyPair>> newElemsOrig = new HashSet<>(elems);
+    List<Set<Constraint<UnifyPair>>> newOderConstraintsOrig = new ArrayList<>(oderConstraints);
+    newElemsOrig.add(a);
+
+    /* FORK ANFANG */
+    TypeUnify2Task forkOrig = new TypeUnify2Task(newElemsOrig, newEqOrig, newOderConstraintsOrig, a, fc, context, rekTiefe, new HashSet<>(methodSignatureConstraint));
+    typeUnifyTask.addChildTask(forkOrig);
+    // schedule compute() on another thread
+    CompletableFuture<Set<Set<UnifyPair>>> forkOrigFuture = CompletableFuture.supplyAsync(forkOrig::compute, context.executor()).thenCompose(f -> f);
+    resultValues = resultValues.thenCombine(forkOrigFuture,
+      (prevResults, currentThreadResult) -> {
+        forkOrig.writeLog("final Orig 0");
+        forkOrig.closeLogFile();
+        return new Tuple<>(currentThreadResult, prevResults.getSecond());
+      });
+
+    //forks.add(forkOrig);
+    if (typeUnifyTask.myIsCancelled()) {
+      throw new UnifyCancelException();
+    }
+    /* FORK ENDE */
+
+    writeLog("a in " + variance + " " + a);
+    writeLog("nextSetasListRest: " + nextSetasListRest.toString());
+
+    while (!nextSetasListRest.isEmpty()) {
+      Set<UnifyPair> nSaL = nextSetasListRest.removeFirst();
+      nextSetAsList.remove(nSaL);
+      writeLog("0 RM" + nSaL.toString());
+
+      if (!this.isOderConstraint) {
+        //ueberpruefung ob zu a =. ty \in nSaL in sameEqSet ein Widerspruch besteht
+        if (!sameEqSet.isEmpty() && !typeUnifyTask.checkNoContradiction(nSaL, sameEqSet, result)) {
+          TypeUnifyTask.noShortendElements++;
+          continue;
+        }
+      } else {
+        nextSetasListOderConstraints.add(((Constraint<UnifyPair>) nSaL).getExtendConstraint());
+      }
+      Set<UnifyPair> newEq = new HashSet<>(eq);
+      Set<Set<UnifyPair>> newElems = new HashSet<>(elems);
+      List<Set<Constraint<UnifyPair>>> newOderConstraints = new ArrayList<>(oderConstraints);
+      newElems.add(nSaL);
+      TypeUnify2Task fork = new TypeUnify2Task(newElems, newEq, newOderConstraints, nSaL, fc, context, rekTiefe, new HashSet<>(methodSignatureConstraint));
+      typeUnifyTask.addChildTask(fork);
+      // schedule compute() on another thread
+      CompletableFuture<Set<Set<UnifyPair>>> forkFuture = CompletableFuture.supplyAsync(fork::compute, context.executor()).thenCompose(f -> f);
+      resultValues = resultValues.thenCombine(forkFuture,
+        (prevResults, fork_res) -> {
+          if (typeUnifyTask.myIsCancelled()) {
+            throw new UnifyCancelException();
+          }
+          writeLog("fork_res: " + fork_res.toString());
+          writeLog(Boolean.valueOf((typeUnifyTask.isUndefinedPairSetSet(fork_res))).toString());
+          prevResults.getSecond().add(fork_res);
+          if (!typeUnifyTask.isUndefinedPairSetSet(fork_res)) {
+            aParDef.add(fork.getNextSetElement());
+          }
+          fork.writeLog("final 0");
+          fork.closeLogFile();
+          return prevResults;
+        }
+      );
+
+      if (typeUnifyTask.myIsCancelled()) {
+        throw new UnifyCancelException();
+      }
+    }
+
+    return resultValues;
   }
 
   @Override
@@ -75,7 +172,7 @@ public class Variance0Case extends VarianceCase {
     Set<UnifyPair> compResult,
     Set<UnifyPair> compRes
   ) {
-    writeLog("RES var=1 ADD:" + result.toString() + " " + currentThreadResult.toString());
+    writeLog("RES var=0 ADD:" + result.toString() + " " + currentThreadResult.toString());
     result.addAll(currentThreadResult);
   }
 
@@ -88,24 +185,43 @@ public class Variance0Case extends VarianceCase {
     if (!this.isOderConstraint) {
       return true;
     } else {
+
       nextSetAsList.removeAll(nextSetasListOderConstraints);
       nextSetasListOderConstraints = new ArrayList<>();
       writeLog("Removed: " + nextSetasListOderConstraints);
-      List<Set<UnifyPair>> smallerSetasList = typeUnifyTask.oup.smallerThan(a, nextSetAsList);
+      final List<Set<UnifyPair>> smallerSetasList = typeUnifyTask.oup.smallerThan(a, nextSetAsList);
       List<Set<UnifyPair>> notInherited = smallerSetasList.stream()
         .filter(x -> !((Constraint<UnifyPair>) x).isInherited())
         .collect(Collectors.toCollection(ArrayList::new));
-      List<Set<UnifyPair>> notErased = new ArrayList<>();
+      final List<Set<UnifyPair>> notErased = new ArrayList<>();
       notInherited.forEach(x -> notErased.addAll(typeUnifyTask.oup.smallerEqThan(x, smallerSetasList)));
       List<Set<UnifyPair>> erased = new ArrayList<>(smallerSetasList);
       erased.removeAll(notErased);
       nextSetAsList.removeAll(erased);
-
       writeLog("Removed: " + erased);
-
       writeLog("Not Removed: " + nextSetAsList);
 
+      for (Set<UnifyPair> aPar : aParDef) {
+
+        nextSetAsList.removeAll(nextSetasListOderConstraints);
+        nextSetasListOderConstraints = new ArrayList<>();
+        writeLog("Removed: " + nextSetasListOderConstraints);
+        smallerSetasList.clear();
+        smallerSetasList.addAll(typeUnifyTask.oup.smallerThan(aPar, nextSetAsList));
+        notInherited = smallerSetasList.stream()
+          .filter(x -> !((Constraint<UnifyPair>) x).isInherited())
+          .collect(Collectors.toCollection(ArrayList::new));
+        notErased.clear();
+        notInherited.forEach(x -> notErased.addAll(typeUnifyTask.oup.smallerEqThan(x, smallerSetasList)));
+        erased = new ArrayList<>(smallerSetasList);
+        erased.removeAll(notErased);
+        nextSetAsList.removeAll(erased);
+        writeLog("Removed: " + erased);
+        writeLog("Not Removed: " + nextSetAsList);
+      }
+
     }
+
     return false;
   }
 

src/main/java/de/dhbwstuttgart/typeinference/unify/cartesianproduct/Variance1Case.java

@@ -72,6 +72,7 @@ public class Variance1Case extends VarianceCase {
 
     /* FORK ANFANG */
     TypeUnify2Task forkOrig = new TypeUnify2Task(newElemsOrig, newEqOrig, newOderConstraintsOrig, a, fc, context, rekTiefe, methodSignatureConstraint);
+    typeUnifyTask.addChildTask(forkOrig);
     // schedule compute() on another thread
     CompletableFuture<Set<Set<UnifyPair>>> forkOrigFuture = CompletableFuture.supplyAsync(forkOrig::compute, context.executor()).thenCompose(f -> f);
     resultValues = resultValues.thenCombine(forkOrigFuture,
@@ -108,6 +109,7 @@ public class Variance1Case extends VarianceCase {
       List<Set<Constraint<UnifyPair>>> newOderConstraints = new ArrayList<>(oderConstraints);
       newElems.add(nSaL);
       TypeUnify2Task fork = new TypeUnify2Task(newElems, newEq, newOderConstraints, nSaL, fc, context, rekTiefe, new HashSet<>(methodSignatureConstraint));
+      typeUnifyTask.addChildTask(fork);
       // schedule compute() on another thread
       CompletableFuture<Set<Set<UnifyPair>>> forkFuture = CompletableFuture.supplyAsync(fork::compute, context.executor()).thenCompose(f -> f);
       resultValues = resultValues.thenCombine(forkFuture,

src/main/java/de/dhbwstuttgart/typeinference/unify/cartesianproduct/Variance2Case.java

@@ -60,6 +60,7 @@ public class Variance2Case extends VarianceCase {
 
     /* FORK ANFANG */
     TypeUnify2Task forkOrig = new TypeUnify2Task(newElemsOrig, newEqOrig, newOderConstraintsOrig, a, fc, context, rekTiefe, new HashSet<>(methodSignatureConstraint));
+    typeUnifyTask.addChildTask(forkOrig);
     CompletableFuture<Set<Set<UnifyPair>>> forkOrigFuture = CompletableFuture.supplyAsync(forkOrig::compute, context.executor()).thenCompose(f -> f);
     resultValuesFuture = forkOrigFuture.thenApply((currentThreadResult) -> {
       forkOrig.writeLog("final Orig 2");
@@ -89,6 +90,7 @@ public class Variance2Case extends VarianceCase {
       List<Set<Constraint<UnifyPair>>> newOderConstraints = new ArrayList<>(oderConstraints);
       newElems.add(nSaL);
       TypeUnify2Task fork = new TypeUnify2Task(newElems, newEq, newOderConstraints, nSaL, fc, context, rekTiefe, new HashSet<>(methodSignatureConstraintForParallel));
+      typeUnifyTask.addChildTask(fork);
       CompletableFuture<Set<Set<UnifyPair>>> forkFuture = CompletableFuture.supplyAsync(fork::compute, context.executor()).thenCompose(f -> f);
       resultValuesFuture = resultValuesFuture.thenCombine(forkFuture, (resultValues, fork_res) -> {
         if (typeUnifyTask.myIsCancelled()) {

src/main/java/de/dhbwstuttgart/typeinference/unify/cartesianproduct/VarianceM1Case.java

@@ -72,6 +72,7 @@ public class VarianceM1Case extends VarianceCase {
 
     /* FORK ANFANG */
     TypeUnify2Task forkOrig = new TypeUnify2Task(newElemsOrig, newEqOrig, newOderConstraintsOrig, a, fc, context, rekTiefe, methodSignatureConstraint);
+    typeUnifyTask.addChildTask(forkOrig);
     // schedule compute() on another thread
     CompletableFuture<Set<Set<UnifyPair>>> forkOrigFuture = CompletableFuture.supplyAsync(forkOrig::compute, context.executor()).thenCompose(f -> f);
     resultValues = resultValues.thenCombine(forkOrigFuture,
@@ -109,6 +110,7 @@ public class VarianceM1Case extends VarianceCase {
       List<Set<Constraint<UnifyPair>>> newOderConstraints = new ArrayList<>(oderConstraints);
       newElems.add(nSaL);
       TypeUnify2Task fork = new TypeUnify2Task(newElems, newEq, newOderConstraints, nSaL, fc, context, rekTiefe, new HashSet<>(methodSignatureConstraint));
+      typeUnifyTask.addChildTask(fork);
       // schedule compute() on another thread
       CompletableFuture<Set<Set<UnifyPair>>> forkFuture = CompletableFuture.supplyAsync(fork::compute, context.executor()).thenCompose(f -> f);
       resultValues = resultValues.thenCombine(forkFuture,

src/test/java/server/ServerTest.java

@@ -30,10 +30,12 @@ import java.util.Set;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.stream.Collectors;
+import org.junit.Ignore;
 import org.junit.Test;
 import targetast.TestCodegen;
 import static org.junit.Assert.*;
 
+@Ignore("Server tests create huge overhead, so they are ignored until required")
 public class ServerTest {
 
   @Test