import gnu.prolog.database.*;
import gnu.prolog.io.*;
import gnu.prolog.term.*;
import gnu.prolog.vm.*;
import gnu.prolog.vm.interpreter.*;
import java.io.*;

public class Predicate_setup_call_catcher_cleanup extends ExecuteOnlyCode
{
   public int execute(Interpreter interpreter, boolean backtrackMode, gnu.prolog.term.Term args[]) throws PrologException
   {
      Environment environment = interpreter.getEnvironment();
      int rc = SUCCESS;
      // Only call setup the first time
      if (!backtrackMode)
         rc = Predicate_call.staticExecute(interpreter, false, args[0]);
      if (rc == SUCCESS || rc == SUCCESS_LAST)
      {
         try
         {
            rc = Predicate_call.staticExecute(interpreter, backtrackMode, args[1]);
         } 
         catch(PrologException q)
         {
            rc = interpreter.unify(args[2], new CompoundTerm(CompoundTermTag.get(AtomTerm.get("exception"), 1),
                                                             q.getTerm()));
            if (rc == SUCCESS || rc == SUCCESS_LAST)
               return Predicate_call.staticExecute(interpreter, false, args[3]);
            // re-throw exception if unification fails
            else
            {
               throw(q);
            }
         }
         if (rc != SUCCESS)
         {
            // Call cleanup if the 2nd arg fails, has an exception or is finished
            // But first, unify the port with args[3]
            if (rc == FAIL)
               rc = interpreter.unify(args[2], AtomTerm.get("fail"));
            else if (rc == SUCCESS_LAST)
            {
               rc = interpreter.unify(args[2], AtomTerm.get("exit"));
            }
            if (rc == SUCCESS || rc == SUCCESS_LAST)
               return Predicate_call.staticExecute(interpreter, false, args[3]);
            else
               return rc;
         }
         else 
         {
            // Choicepoint has been left.
            BacktrackInfo bt = interpreter.popBacktrackInfo();
            interpreter.pushBacktrackInfo(new BacktrackInfoWithCatcherCleanup(bt, args[2], args[3]));

            return rc;
         }
      }
      else
         return rc;
   }      


   public class BacktrackInfoWithCatcherCleanup extends BacktrackInfoWithCleanup
   {
      Term catcher;
      public BacktrackInfoWithCatcherCleanup(BacktrackInfo bt, Term catcher, Term cleanup)
      {
         super(bt, cleanup);
         this.catcher = catcher;
      }

      public void cleanup(Interpreter interpreter)
      {
         try
         {
            if (interpreter.unify(catcher, AtomTerm.get("!")) == SUCCESS_LAST)
               super.cleanup(interpreter);
         }
         catch(PrologException anything)
         {
         }
      }

   }

}