@Test
 public void codeCacheTestOpt() throws ScriptException, IOException {
   System.setProperty("nashorn.persistent.code.cache", codeCache);
   final NashornScriptEngineFactory fac = new NashornScriptEngineFactory();
   final ScriptEngine e = fac.getScriptEngine(ENGINE_OPTIONS_OPT);
   final Path codeCachePath = getCodeCachePath(true);
   e.eval(code1);
   e.eval(code2);
   e.eval(code3); // less than minimum size for storing
   // adding code1 and code2.
   final DirectoryStream<Path> stream = Files.newDirectoryStream(codeCachePath);
   checkCompiledScripts(stream, 4);
 }
 @Test
 public void changeUserDirTest() throws ScriptException, IOException {
   System.setProperty("nashorn.persistent.code.cache", codeCache);
   final NashornScriptEngineFactory fac = new NashornScriptEngineFactory();
   final ScriptEngine e = fac.getScriptEngine(ENGINE_OPTIONS_NOOPT);
   final Path codeCachePath = getCodeCachePath(false);
   final String newUserDir = "build/newUserDir";
   // Now changing current working directory
   System.setProperty("user.dir", System.getProperty("user.dir") + File.separator + newUserDir);
   try {
     // Check that a new compiled script is stored in existing code cache
     e.eval(code1);
     final DirectoryStream<Path> stream = Files.newDirectoryStream(codeCachePath);
     checkCompiledScripts(stream, 1);
     // Setting to default current working dir
   } finally {
     System.setProperty("user.dir", oldUserDir);
   }
 }
  @Test
  public void pathHandlingTest() {
    System.setProperty("nashorn.persistent.code.cache", codeCache);
    final NashornScriptEngineFactory fac = new NashornScriptEngineFactory();

    fac.getScriptEngine(ENGINE_OPTIONS_NOOPT);

    final Path expectedCodeCachePath =
        FileSystems.getDefault().getPath(oldUserDir + File.separator + codeCache);
    final Path actualCodeCachePath =
        FileSystems.getDefault()
            .getPath(System.getProperty("nashorn.persistent.code.cache"))
            .toAbsolutePath();
    // Check that nashorn code cache is created in current working directory
    assertEquals(actualCodeCachePath, expectedCodeCachePath);
    // Check that code cache dir exists and it's not empty
    final File file = new File(actualCodeCachePath.toUri());
    assertTrue(file.exists(), "No code cache directory was created!");
    assertTrue(file.isDirectory(), "Code cache location is not a directory!");
    assertFalse(file.list().length == 0, "Code cache directory is empty!");
  }
예제 #4
0
/** @author vv, mg */
public class Scripts {

  private static final NashornScriptEngineFactory factory = new NashornScriptEngineFactory();
  private static final NashornScriptEngine engine = (NashornScriptEngine) factory.getScriptEngine();
  protected static final String PLATYPUS_JS_FILENAME = "platypus.js";
  public static final String STRING_TYPE_NAME = "String"; // NOI18N
  public static final String NUMBER_TYPE_NAME = "Number"; // NOI18N
  public static final String DATE_TYPE_NAME = "Date"; // NOI18N
  public static final String BOOLEAN_TYPE_NAME = "Boolean"; // NOI18N
  public static final String GEOMETRY_TYPE_NAME = "Geometry"; // NOI18N
  public static final String THIS_KEYWORD = "this"; // NOI18N
  protected static volatile Path absoluteApiPath;
  protected static volatile URL platypusJsUrl;

  public static NashornScriptEngine getEngine() {
    return engine;
  }

  private static final ThreadLocal<LocalContext> contextRef = new ThreadLocal<>();

  public static Space getSpace() {
    return getContext() != null ? getContext().getSpace() : null;
  }

  public static LocalContext getContext() {
    return contextRef.get();
  }

  public static void setContext(LocalContext aContext) {
    if (aContext != null) {
      contextRef.set(aContext);
    } else {
      contextRef.remove();
    }
  }

  public static class LocalContext {

    protected Object request;
    protected Object response;
    protected Object principal;
    protected Object session;

    protected Integer asyncsCount;

    protected Scripts.Space space;

    public Object getSession() {
      return session;
    }

    public void setSession(Object aValue) {
      session = aValue;
    }

    public Object getRequest() {
      return request;
    }

    public void setRequest(Object aRequest) {
      request = aRequest;
    }

    public Object getResponse() {
      return response;
    }

    public void setResponse(Object aResponse) {
      response = aResponse;
    }

    public Object getPrincipal() {
      return principal;
    }

    public void setPrincipal(Object aSession) {
      principal = aSession;
    }

    public int getAsyncsCount() {
      return asyncsCount != null ? asyncsCount : 0;
    }

    public void incAsyncsCount() {
      if (asyncsCount != null) {
        asyncsCount++;
      }
    }

    public void initAsyncs(Integer aSeed) {
      asyncsCount = aSeed;
    }

    public Space getSpace() {
      return space;
    }

    public void setSpace(Space aValue) {
      space = aValue;
    }
  }

  public static LocalContext createContext(Scripts.Space aSpace) {
    LocalContext res = new LocalContext();
    res.setSpace(aSpace);
    return res;
  }

  public static class Pending {

    protected Consumer<Void> onLoad;
    protected Consumer<Exception> onError;

    public Pending(Consumer<Void> aOnLoad, Consumer<Exception> aOnError) {
      super();
      onLoad = aOnLoad;
      onError = aOnError;
    }

    public void loaded() {
      onLoad.accept(null);
    }

    public void failed(Exception ex) {
      onError.accept(ex);
    }
  }

  public static class Space {

    protected ScriptContext scriptContext;
    protected Object global;
    protected Map<String, JSObject> publishers = new HashMap<>();
    protected Set<String> required = new HashSet<>();
    protected Set<String> executed = new HashSet<>();
    protected Map<String, List<Pending>> pending = new HashMap<>();

    protected Space() {
      this(null);
      global = new Object();
    }

    public Space(ScriptContext aScriptContext) {
      super();
      scriptContext = aScriptContext;
    }

    public Set<String> getRequired() {
      return required;
    }

    public Set<String> getExecuted() {
      return executed;
    }

    public Map<String, List<Pending>> getPending() {
      return pending;
    }

    protected JSObject loadFunc;
    protected JSObject toPrimitiveFunc;
    protected JSObject lookupInGlobalFunc;
    protected JSObject putInGlobalFunc;
    protected JSObject toDateFunc;
    protected JSObject parseJsonFunc;
    protected JSObject parseJsonWithDatesFunc;
    protected JSObject writeJsonFunc;
    protected JSObject extendFunc;
    protected JSObject scalarDefFunc;
    protected JSObject collectionDefFunc;
    protected JSObject isArrayFunc;
    protected JSObject makeObjFunc;
    protected JSObject makeArrayFunc;
    protected JSObject listenFunc;
    protected JSObject listenElementsFunc;
    protected JSObject copyObjectFunc;

    public void setGlobal(Object aValue) {
      if (global == null) {
        global = aValue;
      } else {
        throw new IllegalStateException("Scripts space should be initialized only once.");
      }
    }

    public void putPublisher(String aClassName, JSObject aPublisher) {
      publishers.put(aClassName, aPublisher);
    }

    public JSObject getPublisher(String aClassName) {
      return publishers.get(aClassName);
    }

    public JSObject getLoadFunc() {
      assert loadFunc != null : SCRIPT_NOT_INITIALIZED;
      return loadFunc;
    }

    public void setLoadFunc(JSObject aValue) {
      assert loadFunc == null;
      loadFunc = aValue;
    }

    public JSObject getToPrimitiveFunc() {
      assert toPrimitiveFunc != null : SCRIPT_NOT_INITIALIZED;
      return toPrimitiveFunc;
    }

    public void setToPrimitiveFunc(JSObject aValue) {
      assert toPrimitiveFunc == null;
      toPrimitiveFunc = aValue;
    }

    public void setLookupInGlobalFunc(JSObject aValue) {
      assert lookupInGlobalFunc == null;
      lookupInGlobalFunc = aValue;
    }

    public void setPutInGlobalFunc(JSObject aValue) {
      assert putInGlobalFunc == null;
      putInGlobalFunc = aValue;
    }

    public JSObject getToDateFunc() {
      assert toDateFunc != null;
      return toDateFunc;
    }

    public void setToDateFunc(JSObject aValue) {
      assert toDateFunc == null;
      toDateFunc = aValue;
    }

    public void setParseJsonFunc(JSObject aValue) {
      assert parseJsonFunc == null;
      parseJsonFunc = aValue;
    }

    public void setParseJsonWithDatesFunc(JSObject aValue) {
      assert parseJsonWithDatesFunc == null;
      parseJsonWithDatesFunc = aValue;
    }

    public void setWriteJsonFunc(JSObject aValue) {
      assert writeJsonFunc == null;
      writeJsonFunc = aValue;
    }

    public void setExtendFunc(JSObject aValue) {
      assert extendFunc == null;
      extendFunc = aValue;
    }

    public void setScalarDefFunc(JSObject aValue) {
      assert scalarDefFunc == null;
      scalarDefFunc = aValue;
    }

    public void setCollectionDefFunc(JSObject aValue) {
      assert collectionDefFunc == null;
      collectionDefFunc = aValue;
    }

    public void setIsArrayFunc(JSObject aValue) {
      assert isArrayFunc == null;
      isArrayFunc = aValue;
    }

    public void setMakeObjFunc(JSObject aValue) {
      assert makeObjFunc == null;
      makeObjFunc = aValue;
    }

    public void setMakeArrayFunc(JSObject aValue) {
      assert makeArrayFunc == null;
      makeArrayFunc = aValue;
    }

    public void setListenFunc(JSObject aValue) {
      assert listenFunc == null;
      listenFunc = aValue;
    }

    public void setListenElementsFunc(JSObject aValue) {
      assert listenElementsFunc == null;
      listenElementsFunc = aValue;
    }

    public void setCopyObjectFunc(JSObject aValue) {
      assert copyObjectFunc == null;
      copyObjectFunc = aValue;
    }

    public JSObject getCopyObjectFunc() {
      return copyObjectFunc;
    }

    public Object toJava(Object aValue) {
      if (aValue instanceof ScriptObject) {
        aValue = ScriptUtils.wrap((ScriptObject) aValue);
      }
      if (aValue instanceof JSObject) {
        assert toPrimitiveFunc != null : SCRIPT_NOT_INITIALIZED;
        aValue = toPrimitiveFunc.call(null, new Object[] {aValue});
      } else if (aValue == ScriptRuntime.UNDEFINED) {
        return null;
      }
      return aValue;
    }

    public Object toJs(Object aValue) {
      if (aValue
          instanceof Date) { // force js boxing of date, because of absence js literal of date value
        assert toDateFunc != null : SCRIPT_NOT_INITIALIZED;
        return toDateFunc.call(null, aValue);
      } else if (aValue instanceof HasPublished) {
        return ((HasPublished) aValue).getPublished();
      } else {
        return aValue;
      }
    }

    public Object[] toJs(Object[] aArray) {
      Object[] publishedArgs = new Object[aArray.length];
      for (int i = 0; i < aArray.length; i++) {
        publishedArgs[i] = toJs(aArray[i]);
      }
      return publishedArgs;
    }

    public Object parseJson(String json) {
      assert parseJsonFunc != null : SCRIPT_NOT_INITIALIZED;
      return parseJsonFunc.call(null, new Object[] {json});
    }

    public Object parseJsonWithDates(String json) {
      assert parseJsonWithDatesFunc != null : SCRIPT_NOT_INITIALIZED;
      return parseJsonWithDatesFunc.call(null, new Object[] {json});
    }

    public String toJson(Object aObj) {
      assert writeJsonFunc != null : SCRIPT_NOT_INITIALIZED;
      if (aObj instanceof Undefined) { // nashorn JSON parser could not work with undefined.
        aObj = null;
      }
      if (aObj instanceof JSObject
          || aObj instanceof CharSequence
          || aObj instanceof Number
          || aObj instanceof Boolean
          || aObj instanceof ScriptObject
          || aObj == null) {
        return JSType.toString(writeJsonFunc.call(null, new Object[] {aObj}));
      } else {
        throw new IllegalArgumentException("Java object couldn't be converted to JSON!");
      }
    }

    public void extend(JSObject aChild, JSObject aParent) {
      assert extendFunc != null : SCRIPT_NOT_INITIALIZED;
      extendFunc.call(null, new Object[] {aChild, aParent});
    }

    public JSObject scalarPropertyDefinition(
        JSObject targetEntity, String targetFieldName, String sourceFieldName) {
      assert scalarDefFunc != null : SCRIPT_NOT_INITIALIZED;
      return (JSObject)
          scalarDefFunc.newObject(new Object[] {targetEntity, targetFieldName, sourceFieldName});
    }

    public JSObject collectionPropertyDefinition(
        JSObject sourceEntity, String targetFieldName, String sourceFieldName) {
      assert collectionDefFunc != null : SCRIPT_NOT_INITIALIZED;
      return (JSObject)
          collectionDefFunc.newObject(
              new Object[] {sourceEntity, targetFieldName, sourceFieldName});
    }

    public boolean isArrayDeep(JSObject aInstance) {
      assert isArrayFunc != null : SCRIPT_NOT_INITIALIZED;
      Object oResult = isArrayFunc.call(null, new Object[] {aInstance});
      return Boolean.TRUE.equals(oResult);
    }

    public JSObject makeObj() {
      assert makeObjFunc != null : SCRIPT_NOT_INITIALIZED;
      Object oResult = makeObjFunc.call(null, new Object[] {});
      return (JSObject) oResult;
    }

    public JSObject makeArray() {
      assert makeArrayFunc != null : SCRIPT_NOT_INITIALIZED;
      Object oResult = makeArrayFunc.call(null, new Object[] {});
      return (JSObject) oResult;
    }

    private static class Wrapper {

      public Object value;
    }

    public Object makeCopy(Object aSource) {
      assert copyObjectFunc != null : SCRIPT_NOT_INITIALIZED;
      Wrapper w = new Wrapper();
      copyObjectFunc.call(
          null,
          new Object[] {
            aSource,
            new AbstractJSObject() {

              @Override
              public Object call(Object thiz, Object... args) {
                w.value = args.length > 0 ? args[0] : null;
                return null;
              }
            }
          });
      return w.value;
    }

    public JSObject listen(JSObject aTarget, String aPath, JSObject aCallback) {
      assert listenFunc != null : SCRIPT_NOT_INITIALIZED;
      Object oResult = listenFunc.call(null, new Object[] {aTarget, aPath, aCallback});
      return (JSObject) oResult;
    }

    public JSObject listenElements(JSObject aTarget, JSObject aCallback) {
      assert listenElementsFunc != null : SCRIPT_NOT_INITIALIZED;
      Object oResult = listenElementsFunc.call(null, new Object[] {aTarget, aCallback});
      return (JSObject) oResult;
    }

    public JSObject createModule(String aModuleName) {
      assert lookupInGlobalFunc != null : SCRIPT_NOT_INITIALIZED;
      Object oConstructor = lookupInGlobalFunc.call(null, new Object[] {aModuleName});
      if (oConstructor instanceof JSObject && ((JSObject) oConstructor).isFunction()) {
        JSObject jsConstructor = (JSObject) oConstructor;
        return (JSObject) jsConstructor.newObject(new Object[] {});
      } else {
        return null;
      }
    }

    public JSObject lookupInGlobal(String aName) {
      assert lookupInGlobalFunc != null : SCRIPT_NOT_INITIALIZED;
      Object res = lookupInGlobalFunc.call(null, new Object[] {aName});
      return res instanceof JSObject ? (JSObject) res : null;
    }

    public void putInGlobal(String aName, JSObject aValue) {
      assert putInGlobalFunc != null : SCRIPT_NOT_INITIALIZED;
      putInGlobalFunc.call(null, new Object[] {aName, aValue});
    }

    public Object exec(String aSourceName, URL aSourcePlace)
        throws ScriptException, URISyntaxException {
      scriptContext.setAttribute(ScriptEngine.FILENAME, aSourceName, ScriptContext.ENGINE_SCOPE);
      return engine.eval(new URLReader(aSourcePlace), scriptContext);
    }

    public Object exec(String aSource) throws ScriptException, URISyntaxException {
      assert scriptContext != null : SCRIPT_NOT_INITIALIZED;
      return engine.eval(aSource, scriptContext);
    }

    public void schedule(JSObject aJsTask, long aTimeout) {
      Scripts.LocalContext context = Scripts.getContext();
      bio.submit(
          () -> {
            try {
              Thread.sleep(aTimeout);
              Scripts.setContext(context);
              try {
                process(
                    () -> {
                      aJsTask.call(null, new Object[] {});
                    });
              } finally {
                Scripts.setContext(null);
              }
            } catch (InterruptedException ex) {
              Logger.getLogger(Scripts.class.getName()).log(Level.SEVERE, null, ex);
            }
          });
    }

    public void enqueue(JSObject aJsTask) {
      process(
          () -> {
            aJsTask.call(null, new Object[] {});
          });
    }

    protected Queue<Runnable> queue = new ConcurrentLinkedQueue<>();
    protected AtomicInteger queueVersion = new AtomicInteger();
    protected AtomicReference worker = new AtomicReference(null);

    public void process(Runnable aTask) {
      Scripts.LocalContext context = Scripts.getContext();
      Runnable taskWrapper =
          () -> {
            Scripts.setContext(context);
            try {
              aTask.run();
            } finally {
              Scripts.setContext(null);
            }
          };
      queue.offer(taskWrapper);
      offerTask(
          () -> {
            // Runnable processedTask = taskWrapper;
            int version;
            int newVersion;
            Thread thisThread = Thread.currentThread();
            do {
              version = queueVersion.get();
              // Zombie counter ...
              newVersion = version + 1;
              if (newVersion == Integer.MAX_VALUE) {
                newVersion = 0;
              }
              /* moved to top of body
              if (processedTask != null) {//Single attempt to offer aTask.
              queue.offer(processedTask);
              processedTask = null;
              }
              */
              if (worker.compareAndSet(null, thisThread)) { // Worker electing.
                try {
                  // already single threaded environment
                  if (global == null) {
                    Scripts.Space.this.initSpaceGlobal();
                  }
                  // Zombie processing ...
                  Runnable task = queue.poll();
                  while (task != null) {
                    task.run();
                    task = queue.poll();
                  }
                } catch (Throwable t) {
                  Logger.getLogger(Scripts.class.getName()).log(Level.SEVERE, null, t);
                } finally {
                  boolean setted = worker.compareAndSet(thisThread, null);
                  assert setted : "Worker electing assumption failed"; // Always successfull CAS.
                }
              }
            } while (!queueVersion.compareAndSet(version, newVersion));
          });
    }

    void initSpaceGlobal() {
      Bindings bindings = engine.createBindings();
      scriptContext.setBindings(bindings, ScriptContext.ENGINE_SCOPE);
      bindings.put("space", this);
      try {
        Scripts.LocalContext ctx = Scripts.createContext(Scripts.Space.this);
        Scripts.setContext(ctx);
        try {
          scriptContext.setAttribute(
              ScriptEngine.FILENAME, PLATYPUS_JS_FILENAME, ScriptContext.ENGINE_SCOPE);
          engine.eval(new URLReader(platypusJsUrl), scriptContext);
        } finally {
          Scripts.setContext(null);
        }
      } catch (ScriptException ex) {
        Logger.getLogger(Scripts.class.getName()).log(Level.SEVERE, null, ex);
      }
    }

    public JSObject readJsArray(Collection<Map<String, Object>> aCollection) {
      JSObject result = makeArray();
      JSObject jsPush = (JSObject) result.getMember("push");
      aCollection.forEach(
          (Map<String, Object> aItem) -> {
            JSObject jsItem = makeObj();
            aItem
                .entrySet()
                .forEach(
                    (Map.Entry<String, Object> aItemContent) -> {
                      jsItem.setMember(aItemContent.getKey(), toJs(aItemContent.getValue()));
                    });
            jsPush.call(result, new Object[] {jsItem});
          });
      return result;
    }
  }

  protected static Consumer<Runnable> tasks;
  // bio thread pool
  protected static ThreadPoolExecutor bio;

  public static void init(Path aAbsoluteApiPath) throws MalformedURLException {
    absoluteApiPath = aAbsoluteApiPath;
    platypusJsUrl = absoluteApiPath.resolve(PLATYPUS_JS_FILENAME).toUri().toURL();
  }

  public static Path getAbsoluteApiPath() {
    return absoluteApiPath;
  }

  public static void initTasks(Consumer<Runnable> aTasks) {
    assert tasks == null : "Scripts tasks are already initialized";
    tasks = aTasks;
  }

  public static void offerTask(Runnable aTask) {
    assert tasks != null : "Scripts tasks are not initialized";
    Scripts.getContext().incAsyncsCount();
    tasks.accept(aTask);
  }

  public static void initBIO(int aMaxThreads) {
    bio =
        new ThreadPoolExecutor(
            aMaxThreads,
            aMaxThreads,
            1L,
            TimeUnit.SECONDS,
            new LinkedBlockingQueue<>(),
            new DeamonThreadFactory("platypus-abio-", false));
    bio.allowCoreThreadTimeOut(true);
  }

  public static void shutdown() {
    if (bio != null) {
      bio.shutdownNow();
    }
  }

  public static void startBIO(Runnable aBioTask) {
    LocalContext context = getContext();
    context.incAsyncsCount();
    bio.submit(
        () -> {
          setContext(context);
          try {
            aBioTask.run();
          } finally {
            setContext(null);
          }
        });
  }

  public static Space createSpace() throws ScriptException {
    Space space = new Space(new SimpleScriptContext());
    return space;
  }

  public static Space createQueue() throws ScriptException {
    Space space = new Space();
    return space;
  }

  public static boolean isInitialized() {
    Space space = getContext() != null ? getContext().getSpace() : null;
    return space != null
        && space.listenElementsFunc != null
        && space.listenFunc != null
        && space.scalarDefFunc != null
        && space.collectionDefFunc != null;
  }

  public static boolean isValidJsIdentifier(final String aName) {
    if (aName != null && !aName.trim().isEmpty()) {
      try {
        FunctionNode astRoot = parseJs(String.format("function %s() {}", aName));
        return astRoot != null && !astRoot.getBody().getStatements().isEmpty();
      } catch (Exception ex) {
        return false;
      }
    }
    return false;
  }

  public static FunctionNode parseJs(String aJsContent) {
    Source source = Source.sourceFor("", aJsContent); // NOI18N
    Options options = new Options(null);
    ScriptEnvironment env = new ScriptEnvironment(options, null, null);
    ErrorManager errors = new ErrorManager();
    Parser p = new Parser(env, source, errors);
    return p.parse();
  }

  /**
   * Extracts the comments tokens from a JavaScript source.
   *
   * @param aSource a source
   * @return a list of comment tokens
   */
  public static List<Long> getCommentsTokens(String aSource) {
    TokenStream tokens = new TokenStream();
    Lexer lexer = new Lexer(Source.sourceFor("", aSource), tokens); // NOI18N
    long t;
    TokenType tt = TokenType.EOL;
    int i = 0;
    List<Long> commentsTokens = new ArrayList<>();
    while (tt != TokenType.EOF) {
      // Get next token in nashorn's parser way
      while (i > tokens.last()) {
        if (tokens.isFull()) {
          tokens.grow();
        }
        lexer.lexify();
      }
      t = tokens.get(i++);
      tt = Token.descType(t);
      if (tt == TokenType.COMMENT) {
        commentsTokens.add(t);
      }
    }
    return commentsTokens;
  }

  /**
   * Removes all commentaries from some JavaScript code.
   *
   * @param text a source
   * @return comments-free JavaScript code
   */
  public static String removeComments(String text) {
    StringBuilder sb = new StringBuilder();
    int i = 0;
    for (Long t : getCommentsTokens(text)) {
      int offset = Token.descPosition(t);
      int lenght = Token.descLength(t);
      sb.append(text.substring(i, offset));
      for (int j = 0; j < lenght; j++) {
        sb.append(" "); // NOI18N
      }
      i = offset + lenght;
    }
    sb.append(text.substring(i));
    return sb.toString();
  }

  /**
   * Searches for all <code>this</code> aliases in a constructor.
   *
   * @param moduleConstructor a constructor to search in
   * @return a set of aliases including <code>this</code> itself
   */
  public static Set<String> getThisAliases(final FunctionNode moduleConstructor) {
    final Set<String> aliases = new HashSet<>();
    if (moduleConstructor != null && moduleConstructor.getBody() != null) {
      aliases.add(THIS_KEYWORD);
      LexicalContext lc = new LexicalContext();
      moduleConstructor.accept(
          new NodeOperatorVisitor<LexicalContext>(lc) {

            @Override
            public boolean enterVarNode(VarNode varNode) {
              if (lc.getCurrentFunction() == moduleConstructor) {
                if (varNode.getAssignmentSource() instanceof IdentNode) {
                  IdentNode in = (IdentNode) varNode.getAssignmentSource();
                  if (THIS_KEYWORD.equals(in.getName())) {
                    aliases.add(varNode.getAssignmentDest().getName());
                  }
                }
              }
              return super.enterVarNode(varNode);
            }
          });
    }
    return aliases;
  }

  protected static final String SCRIPT_NOT_INITIALIZED =
      "Platypus script functions are not initialized.";

  public static void unlisten(JSObject aCookie) {
    JSObject unlisten = (JSObject) aCookie.getMember("unlisten");
    unlisten.call(null, new Object[] {});
  }

  public static boolean isInNode(Node node, int offset) {
    return node.getStart() <= offset && offset <= node.getFinish() + 1;
  }

  public static boolean isInNode(Node outerNode, Node innerNode) {
    return outerNode.getStart() <= innerNode.getStart()
        && innerNode.getFinish() <= outerNode.getFinish();
  }

  public static Node getOffsetNode(Node node, final int offset) {
    GetOffsetNodeVisitorSupport vs = new GetOffsetNodeVisitorSupport(node, offset);
    Node offsetNode = vs.getOffsetNode();
    return offsetNode != null ? offsetNode : node;
  }

  private static class GetOffsetNodeVisitorSupport {

    private final Node root;
    private final int offset;
    private Node offsetNode;

    public GetOffsetNodeVisitorSupport(Node root, int offset) {
      this.root = root;
      this.offset = offset;
    }

    public Node getOffsetNode() {
      final LexicalContext lc = new LexicalContext();
      root.accept(
          new NodeVisitor<LexicalContext>(lc) {

            @Override
            protected boolean enterDefault(Node node) {
              if (isInNode(node, offset)) {
                offsetNode = node;
                return true;
              }
              return false;
            }
          });
      return offsetNode;
    }
  }
}