Add CVC4 implementation for prover based shutdown

Author: BaierD

src/org/sosy_lab/java_smt/solvers/cvc4/CVC4TheoremProver.java

@@ -24,6 +24,7 @@
 import java.util.Optional;
 import java.util.Set;
 import org.checkerframework.checker.nullness.qual.Nullable;
+import org.sosy_lab.common.ShutdownManager;
 import org.sosy_lab.common.ShutdownNotifier;
 import org.sosy_lab.java_smt.api.BasicProverEnvironment;
 import org.sosy_lab.java_smt.api.BooleanFormula;
@@ -202,11 +203,12 @@ public boolean isUnsat() throws InterruptedException, SolverException {
     }
 
     Result result;
-    try (ShutdownHook hook = new ShutdownHook(shutdownNotifier, smtEngine::interrupt)) {
-      shutdownNotifier.shutdownIfNecessary();
+    try (ShutdownHook hook =
+        new ShutdownHook(proverShutdownManager.getNotifier(), smtEngine::interrupt)) {
+      proverShutdownManager.getNotifier().shutdownIfNecessary();
       result = smtEngine.checkSat();
     }
-    shutdownNotifier.shutdownIfNecessary();
+    proverShutdownManager.getNotifier().shutdownIfNecessary();
     return convertSatResult(result);
   }
 
@@ -260,4 +262,9 @@ public void close() {
     }
     super.close();
   }
+
+  @Override
+  protected ShutdownManager getShutdownManagerForProverImpl() throws UnsupportedOperationException {
+    return proverShutdownManager;
+  }
 }