1 /* 2 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package jdk.nashorn.api.scripting; 27 28 import static jdk.nashorn.internal.runtime.ECMAErrors.referenceError; 29 import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED; 30 31 import java.io.IOException; 32 import java.io.InputStream; 33 import java.io.InputStreamReader; 34 import java.io.Reader; 35 import java.lang.reflect.Method; 36 import java.lang.reflect.Modifier; 37 import java.net.URL; 38 import java.nio.charset.Charset; 39 import java.security.AccessControlContext; 40 import java.security.AccessController; 41 import java.security.Permissions; 42 import java.security.PrivilegedAction; 43 import java.security.PrivilegedActionException; 44 import java.security.PrivilegedExceptionAction; 45 import java.security.ProtectionDomain; 46 import java.text.MessageFormat; 47 import java.util.Locale; 48 import java.util.ResourceBundle; 49 import javax.script.AbstractScriptEngine; 50 import javax.script.Bindings; 51 import javax.script.Compilable; 52 import javax.script.CompiledScript; 53 import javax.script.Invocable; 54 import javax.script.ScriptContext; 55 import javax.script.ScriptEngine; 56 import javax.script.ScriptEngineFactory; 57 import javax.script.ScriptException; 58 import javax.script.SimpleBindings; 59 import jdk.nashorn.internal.runtime.Context; 60 import jdk.nashorn.internal.runtime.ErrorManager; 61 import jdk.nashorn.internal.runtime.GlobalObject; 62 import jdk.nashorn.internal.runtime.Property; 63 import jdk.nashorn.internal.runtime.ScriptFunction; 64 import jdk.nashorn.internal.runtime.ScriptObject; 65 import jdk.nashorn.internal.runtime.ScriptRuntime; 66 import jdk.nashorn.internal.runtime.Source; 67 import jdk.nashorn.internal.runtime.linker.JavaAdapterFactory; 68 import jdk.nashorn.internal.runtime.options.Options; 69 70 /** 71 * JSR-223 compliant script engine for Nashorn. Instances are not created directly, but rather returned through 72 * {@link NashornScriptEngineFactory#getScriptEngine()}. Note that this engine implements the {@link Compilable} and 73 * {@link Invocable} interfaces, allowing for efficient precompilation and repeated execution of scripts. 74 * @see NashornScriptEngineFactory 75 */ 76 77 public final class NashornScriptEngine extends AbstractScriptEngine implements Compilable, Invocable { 78 /** 79 * Key used to associate Nashorn global object mirror with arbitrary Bindings instance. 80 */ 81 public static final String NASHORN_GLOBAL = "nashorn.global"; 82 83 // commonly used access control context objects 84 private static AccessControlContext createPermAccCtxt(final String permName) { 85 final Permissions perms = new Permissions(); 86 perms.add(new RuntimePermission(permName)); 87 return new AccessControlContext(new ProtectionDomain[] { new ProtectionDomain(null, perms) }); 88 } 89 90 private static final AccessControlContext CREATE_CONTEXT_ACC_CTXT = createPermAccCtxt(Context.NASHORN_CREATE_CONTEXT); 91 private static final AccessControlContext CREATE_GLOBAL_ACC_CTXT = createPermAccCtxt(Context.NASHORN_CREATE_GLOBAL); 92 93 // the factory that created this engine 94 private final ScriptEngineFactory factory; 95 // underlying nashorn Context - 1:1 with engine instance 96 private final Context nashornContext; 97 // do we want to share single Nashorn global instance across ENGINE_SCOPEs? 98 private final boolean _global_per_engine; 99 // This is the initial default Nashorn global object. 100 // This is used as "shared" global if above option is true. 101 private final ScriptObject global; 102 // initialized bit late to be made 'final'. 103 // Property object for "context" property of global object. 104 private volatile Property contextProperty; 105 106 // default options passed to Nashorn Options object 107 private static final String[] DEFAULT_OPTIONS = new String[] { "-scripting", "-doe" }; 108 109 // Nashorn script engine error message management 110 private static final String MESSAGES_RESOURCE = "jdk.nashorn.api.scripting.resources.Messages"; 111 112 private static final ResourceBundle MESSAGES_BUNDLE; 113 static { 114 MESSAGES_BUNDLE = ResourceBundle.getBundle(MESSAGES_RESOURCE, Locale.getDefault()); 115 } 116 117 // helper to get Nashorn script engine error message 118 private static String getMessage(final String msgId, final String... args) { 119 try { 120 return new MessageFormat(MESSAGES_BUNDLE.getString(msgId)).format(args); 121 } catch (final java.util.MissingResourceException e) { 122 throw new RuntimeException("no message resource found for message id: "+ msgId); 123 } 124 } 125 126 // load engine.js and return content as a char[] 127 @SuppressWarnings("resource") 128 private static char[] loadEngineJSSource() { 129 final String script = "resources/engine.js"; 130 try { 131 final InputStream is = AccessController.doPrivileged( 132 new PrivilegedExceptionAction<InputStream>() { 133 @Override 134 public InputStream run() throws Exception { 135 final URL url = NashornScriptEngine.class.getResource(script); 136 return url.openStream(); 137 } 138 }); 139 return Source.readFully(new InputStreamReader(is)); 140 } catch (final PrivilegedActionException | IOException e) { 141 if (Context.DEBUG) { 142 e.printStackTrace(); 143 } 144 throw new RuntimeException(e); 145 } 146 } 147 148 // Source object for engine.js 149 private static final Source ENGINE_SCRIPT_SRC = new Source(NashornException.ENGINE_SCRIPT_SOURCE_NAME, loadEngineJSSource()); 150 151 NashornScriptEngine(final NashornScriptEngineFactory factory, final ClassLoader appLoader) { 152 this(factory, DEFAULT_OPTIONS, appLoader); 153 } 154 155 NashornScriptEngine(final NashornScriptEngineFactory factory, final String[] args, final ClassLoader appLoader) { 156 this.factory = factory; 157 final Options options = new Options("nashorn"); 158 options.process(args); 159 160 // throw ParseException on first error from script 161 final ErrorManager errMgr = new Context.ThrowErrorManager(); 162 // create new Nashorn Context 163 this.nashornContext = AccessController.doPrivileged(new PrivilegedAction<Context>() { 164 @Override 165 public Context run() { 166 try { 167 return new Context(options, errMgr, appLoader); 168 } catch (final RuntimeException e) { 169 if (Context.DEBUG) { 170 e.printStackTrace(); 171 } 172 throw e; 173 } 174 } 175 }, CREATE_CONTEXT_ACC_CTXT); 176 177 // cache this option that is used often 178 this._global_per_engine = nashornContext.getEnv()._global_per_engine; 179 180 // create new global object 181 this.global = createNashornGlobal(context); 182 // set the default ENGINE_SCOPE object for the default context 183 context.setBindings(new ScriptObjectMirror(global, global), ScriptContext.ENGINE_SCOPE); 184 } 185 186 @Override 187 public Object eval(final Reader reader, final ScriptContext ctxt) throws ScriptException { 188 try { 189 if (reader instanceof URLReader) { 190 final URL url = ((URLReader)reader).getURL(); 191 final Charset cs = ((URLReader)reader).getCharset(); 192 return evalImpl(compileImpl(new Source(url.toString(), url, cs), ctxt), ctxt); 193 } 194 return evalImpl(Source.readFully(reader), ctxt); 195 } catch (final IOException e) { 196 throw new ScriptException(e); 197 } 198 } 199 200 @Override 201 public Object eval(final String script, final ScriptContext ctxt) throws ScriptException { 202 return evalImpl(script.toCharArray(), ctxt); 203 } 204 205 @Override 206 public ScriptEngineFactory getFactory() { 207 return factory; 208 } 209 210 @Override 211 public Bindings createBindings() { 212 if (_global_per_engine) { 213 // just create normal SimpleBindings. 214 // We use same 'global' for all Bindings. 215 return new SimpleBindings(); 216 } 217 return createGlobalMirror(null); 218 } 219 220 // Compilable methods 221 222 @Override 223 public CompiledScript compile(final Reader reader) throws ScriptException { 224 try { 225 return asCompiledScript(compileImpl(Source.readFully(reader), context)); 226 } catch (final IOException e) { 227 throw new ScriptException(e); 228 } 229 } 230 231 @Override 232 public CompiledScript compile(final String str) throws ScriptException { 233 return asCompiledScript(compileImpl(str.toCharArray(), context)); 234 } 235 236 // Invocable methods 237 238 @Override 239 public Object invokeFunction(final String name, final Object... args) 240 throws ScriptException, NoSuchMethodException { 241 return invokeImpl(null, name, args); 242 } 243 244 @Override 245 public Object invokeMethod(final Object thiz, final String name, final Object... args) 246 throws ScriptException, NoSuchMethodException { 247 if (thiz == null) { 248 throw new IllegalArgumentException(getMessage("thiz.cannot.be.null")); 249 } 250 return invokeImpl(thiz, name, args); 251 } 252 253 @Override 254 public <T> T getInterface(final Class<T> clazz) { 255 return getInterfaceInner(null, clazz); 256 } 257 258 @Override 259 public <T> T getInterface(final Object thiz, final Class<T> clazz) { 260 if (thiz == null) { 261 throw new IllegalArgumentException(getMessage("thiz.cannot.be.null")); 262 } 263 return getInterfaceInner(thiz, clazz); 264 } 265 266 // These are called from the "engine.js" script 267 268 /** 269 * This hook is used to search js global variables exposed from Java code. 270 * 271 * @param self 'this' passed from the script 272 * @param ctxt current ScriptContext in which name is searched 273 * @param name name of the variable searched 274 * @return the value of the named variable 275 */ 276 public Object __noSuchProperty__(final Object self, final ScriptContext ctxt, final String name) { 277 if (ctxt != null) { 278 final int scope = ctxt.getAttributesScope(name); 279 final ScriptObject ctxtGlobal = getNashornGlobalFrom(ctxt); 280 if (scope != -1) { 281 return ScriptObjectMirror.unwrap(ctxt.getAttribute(name, scope), ctxtGlobal); 282 } 283 284 if (self == UNDEFINED) { 285 // scope access and so throw ReferenceError 286 throw referenceError(ctxtGlobal, "not.defined", name); 287 } 288 } 289 290 return UNDEFINED; 291 } 292 293 // Implementation only below this point 294 295 private <T> T getInterfaceInner(final Object thiz, final Class<T> clazz) { 296 if (clazz == null || !clazz.isInterface()) { 297 throw new IllegalArgumentException(getMessage("interface.class.expected")); 298 } 299 300 // perform security access check as early as possible 301 final SecurityManager sm = System.getSecurityManager(); 302 if (sm != null) { 303 if (! Modifier.isPublic(clazz.getModifiers())) { 304 throw new SecurityException(getMessage("implementing.non.public.interface", clazz.getName())); 305 } 306 Context.checkPackageAccess(clazz.getName()); 307 } 308 309 ScriptObject realSelf = null; 310 ScriptObject realGlobal = null; 311 if(thiz == null) { 312 // making interface out of global functions 313 realSelf = realGlobal = getNashornGlobalFrom(context); 314 } else if (thiz instanceof ScriptObjectMirror) { 315 final ScriptObjectMirror mirror = (ScriptObjectMirror)thiz; 316 realSelf = mirror.getScriptObject(); 317 realGlobal = mirror.getHomeGlobal(); 318 if (! realGlobal.isOfContext(nashornContext)) { 319 throw new IllegalArgumentException(getMessage("script.object.from.another.engine")); 320 } 321 } else if (thiz instanceof ScriptObject) { 322 // called from script code. 323 realSelf = (ScriptObject)thiz; 324 realGlobal = Context.getGlobal(); 325 if (realGlobal == null) { 326 throw new IllegalArgumentException(getMessage("no.current.nashorn.global")); 327 } 328 329 if (! realGlobal.isOfContext(nashornContext)) { 330 throw new IllegalArgumentException(getMessage("script.object.from.another.engine")); 331 } 332 } 333 334 if (realSelf == null) { 335 throw new IllegalArgumentException(getMessage("interface.on.non.script.object")); 336 } 337 338 try { 339 final ScriptObject oldGlobal = Context.getGlobal(); 340 final boolean globalChanged = (oldGlobal != realGlobal); 341 try { 342 if (globalChanged) { 343 Context.setGlobal(realGlobal); 344 } 345 346 if (! isInterfaceImplemented(clazz, realSelf)) { 347 return null; 348 } 349 return clazz.cast(JavaAdapterFactory.getConstructor(realSelf.getClass(), clazz).invoke(realSelf)); 350 } finally { 351 if (globalChanged) { 352 Context.setGlobal(oldGlobal); 353 } 354 } 355 } catch(final RuntimeException|Error e) { 356 throw e; 357 } catch(final Throwable t) { 358 throw new RuntimeException(t); 359 } 360 } 361 362 // Retrieve nashorn Global object for a given ScriptContext object 363 private ScriptObject getNashornGlobalFrom(final ScriptContext ctxt) { 364 if (_global_per_engine) { 365 // shared single global object for all ENGINE_SCOPE Bindings 366 return global; 367 } 368 369 final Bindings bindings = ctxt.getBindings(ScriptContext.ENGINE_SCOPE); 370 // is this Nashorn's own Bindings implementation? 371 if (bindings instanceof ScriptObjectMirror) { 372 final ScriptObject sobj = globalFromMirror((ScriptObjectMirror)bindings); 373 if (sobj != null) { 374 return sobj; 375 } 376 } 377 378 // Arbitrary user Bindings implementation. Look for NASHORN_GLOBAL in it! 379 Object scope = bindings.get(NASHORN_GLOBAL); 380 if (scope instanceof ScriptObjectMirror) { 381 final ScriptObject sobj = globalFromMirror((ScriptObjectMirror)scope); 382 if (sobj != null) { 383 return sobj; 384 } 385 } 386 387 // We didn't find associated nashorn global mirror in the Bindings given! 388 // Create new global instance mirror and associate with the Bindings. 389 final ScriptObjectMirror mirror = createGlobalMirror(ctxt); 390 bindings.put(NASHORN_GLOBAL, mirror); 391 return mirror.getScriptObject(); 392 } 393 394 // Retrieve nashorn Global object from a given ScriptObjectMirror 395 private ScriptObject globalFromMirror(final ScriptObjectMirror mirror) { 396 ScriptObject sobj = mirror.getScriptObject(); 397 if (sobj instanceof GlobalObject && sobj.isOfContext(nashornContext)) { 398 return sobj; 399 } 400 401 return null; 402 } 403 404 // Create a new ScriptObjectMirror wrapping a newly created Nashorn Global object 405 private ScriptObjectMirror createGlobalMirror(final ScriptContext ctxt) { 406 final ScriptObject newGlobal = createNashornGlobal(ctxt); 407 return new ScriptObjectMirror(newGlobal, newGlobal); 408 } 409 410 // Create a new Nashorn Global object 411 private ScriptObject createNashornGlobal(final ScriptContext ctxt) { 412 final ScriptObject newGlobal = AccessController.doPrivileged(new PrivilegedAction<ScriptObject>() { 413 @Override 414 public ScriptObject run() { 415 try { 416 return nashornContext.newGlobal(); 417 } catch (final RuntimeException e) { 418 if (Context.DEBUG) { 419 e.printStackTrace(); 420 } 421 throw e; 422 } 423 } 424 }, CREATE_GLOBAL_ACC_CTXT); 425 426 nashornContext.initGlobal(newGlobal); 427 428 final int NON_ENUMERABLE_CONSTANT = Property.NOT_ENUMERABLE | Property.NOT_CONFIGURABLE | Property.NOT_WRITABLE; 429 // current ScriptContext exposed as "context" 430 // "context" is non-writable from script - but script engine still 431 // needs to set it and so save the context Property object 432 contextProperty = newGlobal.addOwnProperty("context", NON_ENUMERABLE_CONSTANT, null); 433 // current ScriptEngine instance exposed as "engine". We added @SuppressWarnings("LeakingThisInConstructor") as 434 // NetBeans identifies this assignment as such a leak - this is a false positive as we're setting this property 435 // in the Global of a Context we just created - both the Context and the Global were just created and can not be 436 // seen from another thread outside of this constructor. 437 newGlobal.addOwnProperty("engine", NON_ENUMERABLE_CONSTANT, this); 438 // global script arguments with undefined value 439 newGlobal.addOwnProperty("arguments", Property.NOT_ENUMERABLE, UNDEFINED); 440 // file name default is null 441 newGlobal.addOwnProperty(ScriptEngine.FILENAME, Property.NOT_ENUMERABLE, null); 442 // evaluate engine.js initialization script this new global object 443 try { 444 evalImpl(compileImpl(ENGINE_SCRIPT_SRC, newGlobal), ctxt, newGlobal); 445 } catch (final ScriptException exp) { 446 throw new RuntimeException(exp); 447 } 448 return newGlobal; 449 } 450 451 // scripts should see "context" and "engine" as variables in the given global object 452 private void setContextVariables(final ScriptObject ctxtGlobal, final ScriptContext ctxt) { 453 // set "context" global variable via contextProperty - because this 454 // property is non-writable 455 contextProperty.setObjectValue(ctxtGlobal, ctxtGlobal, ctxt, false); 456 Object args = ScriptObjectMirror.unwrap(ctxt.getAttribute("arguments"), ctxtGlobal); 457 if (args == null || args == UNDEFINED) { 458 args = ScriptRuntime.EMPTY_ARRAY; 459 } 460 // if no arguments passed, expose it 461 if (! (args instanceof ScriptObject)) { 462 args = ((GlobalObject)ctxtGlobal).wrapAsObject(args); 463 ctxtGlobal.set("arguments", args, false); 464 } 465 } 466 467 private Object invokeImpl(final Object selfObject, final String name, final Object... args) throws ScriptException, NoSuchMethodException { 468 name.getClass(); // null check 469 470 ScriptObjectMirror selfMirror = null; 471 if (selfObject instanceof ScriptObjectMirror) { 472 selfMirror = (ScriptObjectMirror)selfObject; 473 if (! selfMirror.getHomeGlobal().isOfContext(nashornContext)) { 474 throw new IllegalArgumentException(getMessage("script.object.from.another.engine")); 475 } 476 } else if (selfObject instanceof ScriptObject) { 477 // invokeMethod called from script code - in which case we may get 'naked' ScriptObject 478 // Wrap it with oldGlobal to make a ScriptObjectMirror for the same. 479 final ScriptObject oldGlobal = Context.getGlobal(); 480 if (oldGlobal == null) { 481 throw new IllegalArgumentException(getMessage("no.current.nashorn.global")); 482 } 483 484 if (! oldGlobal.isOfContext(nashornContext)) { 485 throw new IllegalArgumentException(getMessage("script.object.from.another.engine")); 486 } 487 488 selfMirror = (ScriptObjectMirror)ScriptObjectMirror.wrap(selfObject, oldGlobal); 489 } else if (selfObject == null) { 490 // selfObject is null => global function call 491 final ScriptObject ctxtGlobal = getNashornGlobalFrom(context); 492 selfMirror = (ScriptObjectMirror)ScriptObjectMirror.wrap(ctxtGlobal, ctxtGlobal); 493 } 494 495 if (selfMirror != null) { 496 try { 497 return ScriptObjectMirror.translateUndefined(selfMirror.call(name, args)); 498 } catch (final Exception e) { 499 final Throwable cause = e.getCause(); 500 if (cause instanceof NoSuchMethodException) { 501 throw (NoSuchMethodException)cause; 502 } 503 throwAsScriptException(e); 504 throw new AssertionError("should not reach here"); 505 } 506 } 507 508 // Non-script object passed as selfObject 509 throw new IllegalArgumentException(getMessage("interface.on.non.script.object")); 510 } 511 512 private Object evalImpl(final char[] buf, final ScriptContext ctxt) throws ScriptException { 513 return evalImpl(compileImpl(buf, ctxt), ctxt); 514 } 515 516 private Object evalImpl(final ScriptFunction script, final ScriptContext ctxt) throws ScriptException { 517 return evalImpl(script, ctxt, getNashornGlobalFrom(ctxt)); 518 } 519 520 private Object evalImpl(final ScriptFunction script, final ScriptContext ctxt, final ScriptObject ctxtGlobal) throws ScriptException { 521 if (script == null) { 522 return null; 523 } 524 final ScriptObject oldGlobal = Context.getGlobal(); 525 final boolean globalChanged = (oldGlobal != ctxtGlobal); 526 try { 527 if (globalChanged) { 528 Context.setGlobal(ctxtGlobal); 529 } 530 531 // set ScriptContext variables if ctxt is non-null 532 if (ctxt != null) { 533 setContextVariables(ctxtGlobal, ctxt); 534 } 535 return ScriptObjectMirror.translateUndefined(ScriptObjectMirror.wrap(ScriptRuntime.apply(script, ctxtGlobal), ctxtGlobal)); 536 } catch (final Exception e) { 537 throwAsScriptException(e); 538 throw new AssertionError("should not reach here"); 539 } finally { 540 if (globalChanged) { 541 Context.setGlobal(oldGlobal); 542 } 543 } 544 } 545 546 private static void throwAsScriptException(final Exception e) throws ScriptException { 547 if (e instanceof ScriptException) { 548 throw (ScriptException)e; 549 } else if (e instanceof NashornException) { 550 final NashornException ne = (NashornException)e; 551 final ScriptException se = new ScriptException( 552 ne.getMessage(), ne.getFileName(), 553 ne.getLineNumber(), ne.getColumnNumber()); 554 se.initCause(e); 555 throw se; 556 } else if (e instanceof RuntimeException) { 557 throw (RuntimeException)e; 558 } else { 559 // wrap any other exception as ScriptException 560 throw new ScriptException(e); 561 } 562 } 563 564 private CompiledScript asCompiledScript(final ScriptFunction script) { 565 return new CompiledScript() { 566 @Override 567 public Object eval(final ScriptContext ctxt) throws ScriptException { 568 return evalImpl(script, ctxt); 569 } 570 @Override 571 public ScriptEngine getEngine() { 572 return NashornScriptEngine.this; 573 } 574 }; 575 } 576 577 private ScriptFunction compileImpl(final char[] buf, final ScriptContext ctxt) throws ScriptException { 578 final Object val = ctxt.getAttribute(ScriptEngine.FILENAME); 579 final String fileName = (val != null) ? val.toString() : "<eval>"; 580 return compileImpl(new Source(fileName, buf), ctxt); 581 } 582 583 private ScriptFunction compileImpl(final Source source, final ScriptContext ctxt) throws ScriptException { 584 return compileImpl(source, getNashornGlobalFrom(ctxt)); 585 } 586 587 private ScriptFunction compileImpl(final Source source, final ScriptObject newGlobal) throws ScriptException { 588 final ScriptObject oldGlobal = Context.getGlobal(); 589 final boolean globalChanged = (oldGlobal != newGlobal); 590 try { 591 if (globalChanged) { 592 Context.setGlobal(newGlobal); 593 } 594 595 return nashornContext.compileScript(source, newGlobal); 596 } catch (final Exception e) { 597 throwAsScriptException(e); 598 throw new AssertionError("should not reach here"); 599 } finally { 600 if (globalChanged) { 601 Context.setGlobal(oldGlobal); 602 } 603 } 604 } 605 606 private static boolean isInterfaceImplemented(final Class<?> iface, final ScriptObject sobj) { 607 for (final Method method : iface.getMethods()) { 608 // ignore methods of java.lang.Object class 609 if (method.getDeclaringClass() == Object.class) { 610 continue; 611 } 612 613 Object obj = sobj.get(method.getName()); 614 if (! (obj instanceof ScriptFunction)) { 615 return false; 616 } 617 } 618 return true; 619 } 620 }