1 /*
2 * Copyright (c) 1996, 2022, 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 java.io;
27
28 import java.security.AccessController;
29 import java.security.PrivilegedAction;
30 import java.util.ArrayList;
31 import java.util.Arrays;
32 import java.util.List;
33 import java.util.Objects;
34 import java.util.StringJoiner;
35 import sun.reflect.misc.ReflectUtil;
36
37 /**
38 * An ObjectOutputStream writes primitive data types and graphs of Java objects
39 * to an OutputStream. The objects can be read (reconstituted) using an
40 * ObjectInputStream. Persistent storage of objects can be accomplished by
41 * using a file for the stream. If the stream is a network socket stream, the
42 * objects can be reconstituted on another host or in another process.
43 *
44 * <p>Only objects that support the java.io.Serializable interface can be
45 * written to streams. The class of each serializable object is encoded
46 * including the class name and signature of the class, the values of the
47 * object's fields and arrays, and the closure of any other objects referenced
48 * from the initial objects.
49 *
50 * <p>The method writeObject is used to write an object to the stream. Any
51 * object, including Strings and arrays, is written with writeObject. Multiple
52 * objects or primitives can be written to the stream. The objects must be
53 * read back from the corresponding ObjectInputstream with the same types and
54 * in the same order as they were written.
55 *
56 * <p>Primitive data types can also be written to the stream using the
57 * appropriate methods from DataOutput. Strings can also be written using the
58 * writeUTF method.
59 *
60 * <p>The default serialization mechanism for an object writes the class of the
61 * object, the class signature, and the values of all non-transient and
62 * non-static fields. References to other objects (except in transient or
63 * static fields) cause those objects to be written also. Multiple references
64 * to a single object are encoded using a reference sharing mechanism so that
65 * graphs of objects can be restored to the same shape as when the original was
66 * written.
67 *
68 * <p>For example to write an object that can be read by the example in
69 * ObjectInputStream:
70 * <br>
71 * <pre>
72 * FileOutputStream fos = new FileOutputStream("t.tmp");
73 * ObjectOutputStream oos = new ObjectOutputStream(fos);
74 *
75 * oos.writeInt(12345);
76 * oos.writeObject("Today");
77 * oos.writeObject(new Date());
78 *
79 * oos.close();
80 * </pre>
81 *
82 * <p>Serializable classes that require special handling during the
83 * serialization and deserialization process should implement methods
84 * with the following signatures:
85 *
86 * <br>
87 * <pre>
88 * private void readObject(java.io.ObjectInputStream stream)
89 * throws IOException, ClassNotFoundException;
90 * private void writeObject(java.io.ObjectOutputStream stream)
91 * throws IOException
92 * private void readObjectNoData()
93 * throws ObjectStreamException;
94 * </pre>
95 *
96 * <p>The method name, modifiers, return type, and number and type of
97 * parameters must match exactly for the method to be used by
98 * serialization or deserialization. The methods should only be
99 * declared to throw checked exceptions consistent with these
100 * signatures.
101 *
102 * <p>The writeObject method is responsible for writing the state of the object
103 * for its particular class so that the corresponding readObject method can
104 * restore it. The method does not need to concern itself with the state
105 * belonging to the object's superclasses or subclasses. State is saved by
106 * writing the individual fields to the ObjectOutputStream using the
107 * writeObject method or by using the methods for primitive data types
108 * supported by DataOutput.
109 *
110 * <p>Serialization does not write out the fields of any object that does not
111 * implement the java.io.Serializable interface. Subclasses of Objects that
112 * are not serializable can be serializable. In this case the non-serializable
113 * class must have a no-arg constructor to allow its fields to be initialized.
114 * In this case it is the responsibility of the subclass to save and restore
115 * the state of the non-serializable class. It is frequently the case that the
116 * fields of that class are accessible (public, package, or protected) or that
117 * there are get and set methods that can be used to restore the state.
118 *
119 * <p>Serialization of an object can be prevented by implementing writeObject
120 * and readObject methods that throw the NotSerializableException. The
121 * exception will be caught by the ObjectOutputStream and abort the
122 * serialization process.
123 *
124 * <p>Implementing the Externalizable interface allows the object to assume
125 * complete control over the contents and format of the object's serialized
126 * form. The methods of the Externalizable interface, writeExternal and
127 * readExternal, are called to save and restore the objects state. When
128 * implemented by a class they can write and read their own state using all of
129 * the methods of ObjectOutput and ObjectInput. It is the responsibility of
130 * the objects to handle any versioning that occurs.
131 *
132 * <p>Enum constants are serialized differently than ordinary serializable or
133 * externalizable objects. The serialized form of an enum constant consists
134 * solely of its name; field values of the constant are not transmitted. To
135 * serialize an enum constant, ObjectOutputStream writes the string returned by
136 * the constant's name method. Like other serializable or externalizable
137 * objects, enum constants can function as the targets of back references
138 * appearing subsequently in the serialization stream. The process by which
139 * enum constants are serialized cannot be customized; any class-specific
140 * writeObject and writeReplace methods defined by enum types are ignored
141 * during serialization. Similarly, any serialPersistentFields or
142 * serialVersionUID field declarations are also ignored--all enum types have a
143 * fixed serialVersionUID of 0L.
144 *
145 * <p>Primitive data, excluding serializable fields and externalizable data, is
146 * written to the ObjectOutputStream in block-data records. A block data record
147 * is composed of a header and data. The block data header consists of a marker
148 * and the number of bytes to follow the header. Consecutive primitive data
149 * writes are merged into one block-data record. The blocking factor used for
150 * a block-data record will be 1024 bytes. Each block-data record will be
151 * filled up to 1024 bytes, or be written whenever there is a termination of
152 * block-data mode. Calls to the ObjectOutputStream methods writeObject,
153 * defaultWriteObject and writeFields initially terminate any existing
154 * block-data record.
155 *
156 * <p>Records are serialized differently than ordinary serializable or externalizable
157 * objects, see <a href="ObjectInputStream.html#record-serialization">record serialization</a>.
158 *
159 * @author Mike Warres
160 * @author Roger Riggs
161 * @see java.io.DataOutput
162 * @see java.io.ObjectInputStream
163 * @see java.io.Serializable
164 * @see java.io.Externalizable
165 * @see <a href="{@docRoot}/../specs/serialization/output.html">
166 * <cite>Java Object Serialization Specification,</cite> Section 2, "Object Output Classes"</a>
167 * @since 1.1
168 */
169 public class ObjectOutputStream
170 extends OutputStream implements ObjectOutput, ObjectStreamConstants
171 {
172
173 private static class Caches {
174 /** cache of subclass security audit results */
175 static final ClassValue<Boolean> subclassAudits =
176 new ClassValue<>() {
177 @Override
178 protected Boolean computeValue(Class<?> type) {
179 return auditSubclass(type);
180 }
181 };
182 }
183
184 /** filter stream for handling block data conversion */
185 private final BlockDataOutputStream bout;
186 /** obj -> wire handle map */
187 private final HandleTable handles;
188 /** obj -> replacement obj map */
189 private final ReplaceTable subs;
190 /** stream protocol version */
191 private int protocol = PROTOCOL_VERSION_2;
192 /** recursion depth */
193 private int depth;
194
195 /** buffer for writing primitive field values */
196 private byte[] primVals;
197
198 /** if true, invoke writeObjectOverride() instead of writeObject() */
199 private final boolean enableOverride;
200 /** if true, invoke replaceObject() */
201 private boolean enableReplace;
202
203 // values below valid only during upcalls to writeObject()/writeExternal()
204 /**
205 * Context during upcalls to class-defined writeObject methods; holds
206 * object currently being serialized and descriptor for current class.
207 * Null when not during writeObject upcall.
208 */
209 private SerialCallbackContext curContext;
210 /** current PutField object */
211 private PutFieldImpl curPut;
212
213 /** custom storage for debug trace info */
214 private final DebugTraceInfoStack debugInfoStack;
215
216 /**
217 * value of "sun.io.serialization.extendedDebugInfo" property,
218 * as true or false for extended information about exception's place
219 */
220 @SuppressWarnings("removal")
221 private static final boolean extendedDebugInfo =
222 java.security.AccessController.doPrivileged(
223 new sun.security.action.GetBooleanAction(
224 "sun.io.serialization.extendedDebugInfo")).booleanValue();
225
226 /**
227 * Creates an ObjectOutputStream that writes to the specified OutputStream.
228 * This constructor writes the serialization stream header to the
229 * underlying stream; callers may wish to flush the stream immediately to
230 * ensure that constructors for receiving ObjectInputStreams will not block
231 * when reading the header.
232 *
233 * <p>If a security manager is installed, this constructor will check for
234 * the "enableSubclassImplementation" SerializablePermission when invoked
235 * directly or indirectly by the constructor of a subclass which overrides
236 * the ObjectOutputStream.putFields or ObjectOutputStream.writeUnshared
237 * methods.
238 *
239 * @param out output stream to write to
240 * @throws IOException if an I/O error occurs while writing stream header
241 * @throws SecurityException if untrusted subclass illegally overrides
242 * security-sensitive methods
243 * @throws NullPointerException if {@code out} is {@code null}
244 * @since 1.4
245 * @see ObjectOutputStream#ObjectOutputStream()
246 * @see ObjectOutputStream#putFields()
247 * @see ObjectInputStream#ObjectInputStream(InputStream)
248 */
249 public ObjectOutputStream(OutputStream out) throws IOException {
250 verifySubclass();
251 bout = new BlockDataOutputStream(out);
252 handles = new HandleTable(10, (float) 3.00);
253 subs = new ReplaceTable(10, (float) 3.00);
254 enableOverride = false;
255 writeStreamHeader();
256 bout.setBlockDataMode(true);
257 if (extendedDebugInfo) {
258 debugInfoStack = new DebugTraceInfoStack();
259 } else {
260 debugInfoStack = null;
261 }
262 }
263
264 /**
265 * Provide a way for subclasses that are completely reimplementing
266 * ObjectOutputStream to not have to allocate private data just used by
267 * this implementation of ObjectOutputStream.
268 *
269 * <p>If there is a security manager installed, this method first calls the
270 * security manager's {@code checkPermission} method with a
271 * {@code SerializablePermission("enableSubclassImplementation")}
272 * permission to ensure it's ok to enable subclassing.
273 *
274 * @throws SecurityException if a security manager exists and its
275 * {@code checkPermission} method denies enabling
276 * subclassing.
277 * @throws IOException if an I/O error occurs while creating this stream
278 * @see SecurityManager#checkPermission
279 * @see java.io.SerializablePermission
280 */
281 protected ObjectOutputStream() throws IOException, SecurityException {
282 @SuppressWarnings("removal")
283 SecurityManager sm = System.getSecurityManager();
284 if (sm != null) {
285 sm.checkPermission(SUBCLASS_IMPLEMENTATION_PERMISSION);
286 }
287 bout = null;
288 handles = null;
289 subs = null;
290 enableOverride = true;
291 debugInfoStack = null;
292 }
293
294 /**
295 * Specify stream protocol version to use when writing the stream.
296 *
297 * <p>This routine provides a hook to enable the current version of
298 * Serialization to write in a format that is backwards compatible to a
299 * previous version of the stream format.
300 *
301 * <p>Every effort will be made to avoid introducing additional
302 * backwards incompatibilities; however, sometimes there is no
303 * other alternative.
304 *
305 * @param version use ProtocolVersion from java.io.ObjectStreamConstants.
306 * @throws IllegalStateException if called after any objects
307 * have been serialized.
308 * @throws IllegalArgumentException if invalid version is passed in.
309 * @throws IOException if I/O errors occur
310 * @see java.io.ObjectStreamConstants#PROTOCOL_VERSION_1
311 * @see java.io.ObjectStreamConstants#PROTOCOL_VERSION_2
312 * @since 1.2
313 */
314 public void useProtocolVersion(int version) throws IOException {
315 if (handles.size() != 0) {
316 // REMIND: implement better check for pristine stream?
317 throw new IllegalStateException("stream non-empty");
318 }
319 switch (version) {
320 case PROTOCOL_VERSION_1:
321 case PROTOCOL_VERSION_2:
322 protocol = version;
323 break;
324
325 default:
326 throw new IllegalArgumentException(
327 "unknown version: " + version);
328 }
329 }
330
331 /**
332 * Write the specified object to the ObjectOutputStream. The class of the
333 * object, the signature of the class, and the values of the non-transient
334 * and non-static fields of the class and all of its supertypes are
335 * written. Default serialization for a class can be overridden using the
336 * writeObject and the readObject methods. Objects referenced by this
337 * object are written transitively so that a complete equivalent graph of
338 * objects can be reconstructed by an ObjectInputStream.
339 *
340 * <p>Exceptions are thrown for problems with the OutputStream and for
341 * classes that should not be serialized. All exceptions are fatal to the
342 * OutputStream, which is left in an indeterminate state, and it is up to
343 * the caller to ignore or recover the stream state.
344 *
345 * @throws InvalidClassException Something is wrong with a class used by
346 * serialization.
347 * @throws NotSerializableException Some object to be serialized does not
348 * implement the java.io.Serializable interface.
349 * @throws IOException Any exception thrown by the underlying
350 * OutputStream.
351 */
352 public final void writeObject(Object obj) throws IOException {
353 if (enableOverride) {
354 writeObjectOverride(obj);
355 return;
356 }
357 try {
358 writeObject0(obj, false);
359 } catch (IOException ex) {
360 if (depth == 0) {
361 writeFatalException(ex);
362 }
363 throw ex;
364 }
365 }
366
367 /**
368 * Method used by subclasses to override the default writeObject method.
369 * This method is called by trusted subclasses of ObjectOutputStream that
370 * constructed ObjectOutputStream using the protected no-arg constructor.
371 * The subclass is expected to provide an override method with the modifier
372 * "final".
373 *
374 * @param obj object to be written to the underlying stream
375 * @throws IOException if there are I/O errors while writing to the
376 * underlying stream
377 * @see #ObjectOutputStream()
378 * @see #writeObject(Object)
379 * @since 1.2
380 */
381 protected void writeObjectOverride(Object obj) throws IOException {
382 }
383
384 /**
385 * Writes an "unshared" object to the ObjectOutputStream. This method is
386 * identical to writeObject, except that it always writes the given object
387 * as a new, unique object in the stream (as opposed to a back-reference
388 * pointing to a previously serialized instance). Specifically:
389 * <ul>
390 * <li>An object written via writeUnshared is always serialized in the
391 * same manner as a newly appearing object (an object that has not
392 * been written to the stream yet), regardless of whether or not the
393 * object has been written previously.
394 *
395 * <li>If writeObject is used to write an object that has been previously
396 * written with writeUnshared, the previous writeUnshared operation
397 * is treated as if it were a write of a separate object. In other
398 * words, ObjectOutputStream will never generate back-references to
399 * object data written by calls to writeUnshared.
400 * </ul>
401 * While writing an object via writeUnshared does not in itself guarantee a
402 * unique reference to the object when it is deserialized, it allows a
403 * single object to be defined multiple times in a stream, so that multiple
404 * calls to readUnshared by the receiver will not conflict. Note that the
405 * rules described above only apply to the base-level object written with
406 * writeUnshared, and not to any transitively referenced sub-objects in the
407 * object graph to be serialized.
408 *
409 * <p>ObjectOutputStream subclasses which override this method can only be
410 * constructed in security contexts possessing the
411 * "enableSubclassImplementation" SerializablePermission; any attempt to
412 * instantiate such a subclass without this permission will cause a
413 * SecurityException to be thrown.
414 *
415 * @param obj object to write to stream
416 * @throws NotSerializableException if an object in the graph to be
417 * serialized does not implement the Serializable interface
418 * @throws InvalidClassException if a problem exists with the class of an
419 * object to be serialized
420 * @throws IOException if an I/O error occurs during serialization
421 * @since 1.4
422 */
423 public void writeUnshared(Object obj) throws IOException {
424 try {
425 writeObject0(obj, true);
426 } catch (IOException ex) {
427 if (depth == 0) {
428 writeFatalException(ex);
429 }
430 throw ex;
431 }
432 }
433
434 /**
435 * Write the non-static and non-transient fields of the current class to
436 * this stream. This may only be called from the writeObject method of the
437 * class being serialized. It will throw the NotActiveException if it is
438 * called otherwise.
439 *
440 * @throws IOException if I/O errors occur while writing to the underlying
441 * {@code OutputStream}
442 */
443 public void defaultWriteObject() throws IOException {
444 SerialCallbackContext ctx = curContext;
445 if (ctx == null) {
446 throw new NotActiveException("not in call to writeObject");
447 }
448 Object curObj = ctx.getObj();
449 ObjectStreamClass curDesc = ctx.getDesc();
450 bout.setBlockDataMode(false);
451 defaultWriteFields(curObj, curDesc);
452 bout.setBlockDataMode(true);
453 }
454
455 /**
456 * Retrieve the object used to buffer persistent fields to be written to
457 * the stream. The fields will be written to the stream when writeFields
458 * method is called.
459 *
460 * @return an instance of the class Putfield that holds the serializable
461 * fields
462 * @throws IOException if I/O errors occur
463 * @since 1.2
464 */
465 public ObjectOutputStream.PutField putFields() throws IOException {
466 if (curPut == null) {
467 SerialCallbackContext ctx = curContext;
468 if (ctx == null) {
469 throw new NotActiveException("not in call to writeObject");
470 }
471 ctx.checkAndSetUsed();
472 ObjectStreamClass curDesc = ctx.getDesc();
473 curPut = new PutFieldImpl(curDesc);
474 }
475 return curPut;
476 }
477
478 /**
479 * Write the buffered fields to the stream.
480 *
481 * @throws IOException if I/O errors occur while writing to the underlying
482 * stream
483 * @throws NotActiveException Called when a classes writeObject method was
484 * not called to write the state of the object.
485 * @since 1.2
486 */
487 public void writeFields() throws IOException {
488 if (curPut == null) {
489 throw new NotActiveException("no current PutField object");
490 }
491 bout.setBlockDataMode(false);
492 curPut.writeFields();
493 bout.setBlockDataMode(true);
494 }
495
496 /**
497 * Reset will disregard the state of any objects already written to the
498 * stream. The state is reset to be the same as a new ObjectOutputStream.
499 * The current point in the stream is marked as reset so the corresponding
500 * ObjectInputStream will be reset at the same point. Objects previously
501 * written to the stream will not be referred to as already being in the
502 * stream. They will be written to the stream again.
503 *
504 * @throws IOException if reset() is invoked while serializing an object.
505 */
506 public void reset() throws IOException {
507 if (depth != 0) {
508 throw new IOException("stream active");
509 }
510 bout.setBlockDataMode(false);
511 bout.writeByte(TC_RESET);
512 clear();
513 bout.setBlockDataMode(true);
514 }
515
516 /**
517 * Subclasses may implement this method to allow class data to be stored in
518 * the stream. By default this method does nothing. The corresponding
519 * method in ObjectInputStream is resolveClass. This method is called
520 * exactly once for each unique class in the stream. The class name and
521 * signature will have already been written to the stream. This method may
522 * make free use of the ObjectOutputStream to save any representation of
523 * the class it deems suitable (for example, the bytes of the class file).
524 * The resolveClass method in the corresponding subclass of
525 * ObjectInputStream must read and use any data or objects written by
526 * annotateClass.
527 *
528 * @param cl the class to annotate custom data for
529 * @throws IOException Any exception thrown by the underlying
530 * OutputStream.
531 */
532 protected void annotateClass(Class<?> cl) throws IOException {
533 }
534
535 /**
536 * Subclasses may implement this method to store custom data in the stream
537 * along with descriptors for dynamic proxy classes.
538 *
539 * <p>This method is called exactly once for each unique proxy class
540 * descriptor in the stream. The default implementation of this method in
541 * {@code ObjectOutputStream} does nothing.
542 *
543 * <p>The corresponding method in {@code ObjectInputStream} is
544 * {@code resolveProxyClass}. For a given subclass of
545 * {@code ObjectOutputStream} that overrides this method, the
546 * {@code resolveProxyClass} method in the corresponding subclass of
547 * {@code ObjectInputStream} must read any data or objects written by
548 * {@code annotateProxyClass}.
549 *
550 * @param cl the proxy class to annotate custom data for
551 * @throws IOException any exception thrown by the underlying
552 * {@code OutputStream}
553 * @see ObjectInputStream#resolveProxyClass(String[])
554 * @since 1.3
555 */
556 protected void annotateProxyClass(Class<?> cl) throws IOException {
557 }
558
559 /**
560 * This method will allow trusted subclasses of ObjectOutputStream to
561 * substitute one object for another during serialization. Replacing
562 * objects is disabled until enableReplaceObject is called. The
563 * enableReplaceObject method checks that the stream requesting to do
564 * replacement can be trusted. The first occurrence of each object written
565 * into the serialization stream is passed to replaceObject. Subsequent
566 * references to the object are replaced by the object returned by the
567 * original call to replaceObject. To ensure that the private state of
568 * objects is not unintentionally exposed, only trusted streams may use
569 * replaceObject.
570 *
571 * <p>The ObjectOutputStream.writeObject method takes a parameter of type
572 * Object (as opposed to type Serializable) to allow for cases where
573 * non-serializable objects are replaced by serializable ones.
574 *
575 * <p>When a subclass is replacing objects it must ensure that either a
576 * complementary substitution must be made during deserialization or that
577 * the substituted object is compatible with every field where the
578 * reference will be stored. Objects whose type is not a subclass of the
579 * type of the field or array element abort the serialization by raising an
580 * exception and the object is not be stored.
581 *
582 * <p>This method is called only once when each object is first
583 * encountered. All subsequent references to the object will be redirected
584 * to the new object. This method should return the object to be
585 * substituted or the original object.
586 *
587 * <p>Null can be returned as the object to be substituted, but may cause
588 * NullReferenceException in classes that contain references to the
589 * original object since they may be expecting an object instead of
590 * null.
591 *
592 * @param obj the object to be replaced
593 * @return the alternate object that replaced the specified one
594 * @throws IOException Any exception thrown by the underlying
595 * OutputStream.
596 */
597 protected Object replaceObject(Object obj) throws IOException {
598 return obj;
599 }
600
601 /**
602 * Enables the stream to do replacement of objects written to the stream. When
603 * enabled, the {@link #replaceObject} method is called for every object being
604 * serialized.
605 *
606 * <p>If object replacement is currently not enabled, and
607 * {@code enable} is true, and there is a security manager installed,
608 * this method first calls the security manager's
609 * {@code checkPermission} method with the
610 * {@code SerializablePermission("enableSubstitution")} permission to
611 * ensure that the caller is permitted to enable the stream to do replacement
612 * of objects written to the stream.
613 *
614 * @param enable true for enabling use of {@code replaceObject} for
615 * every object being serialized
616 * @return the previous setting before this method was invoked
617 * @throws SecurityException if a security manager exists and its
618 * {@code checkPermission} method denies enabling the stream
619 * to do replacement of objects written to the stream.
620 * @see SecurityManager#checkPermission
621 * @see java.io.SerializablePermission
622 */
623 protected boolean enableReplaceObject(boolean enable)
624 throws SecurityException
625 {
626 if (enable == enableReplace) {
627 return enable;
628 }
629 if (enable) {
630 @SuppressWarnings("removal")
631 SecurityManager sm = System.getSecurityManager();
632 if (sm != null) {
633 sm.checkPermission(SUBSTITUTION_PERMISSION);
634 }
635 }
636 enableReplace = enable;
637 return !enableReplace;
638 }
639
640 /**
641 * The writeStreamHeader method is provided so subclasses can append or
642 * prepend their own header to the stream. It writes the magic number and
643 * version to the stream.
644 *
645 * @throws IOException if I/O errors occur while writing to the underlying
646 * stream
647 */
648 protected void writeStreamHeader() throws IOException {
649 bout.writeShort(STREAM_MAGIC);
650 bout.writeShort(STREAM_VERSION);
651 }
652
653 /**
654 * Write the specified class descriptor to the ObjectOutputStream. Class
655 * descriptors are used to identify the classes of objects written to the
656 * stream. Subclasses of ObjectOutputStream may override this method to
657 * customize the way in which class descriptors are written to the
658 * serialization stream. The corresponding method in ObjectInputStream,
659 * {@link ObjectInputStream#readClassDescriptor readClassDescriptor}, should then be overridden to
660 * reconstitute the class descriptor from its custom stream representation.
661 * By default, this method writes class descriptors according to the format
662 * defined in the <a href="{@docRoot}/../specs/serialization/index.html">
663 * <cite>Java Object Serialization Specification</cite></a>.
664 *
665 * <p>Note that this method will only be called if the ObjectOutputStream
666 * is not using the old serialization stream format (set by calling
667 * ObjectOutputStream's {@code useProtocolVersion} method). If this
668 * serialization stream is using the old format
669 * ({@code PROTOCOL_VERSION_1}), the class descriptor will be written
670 * internally in a manner that cannot be overridden or customized.
671 *
672 * @param desc class descriptor to write to the stream
673 * @throws IOException If an I/O error has occurred.
674 * @see java.io.ObjectInputStream#readClassDescriptor()
675 * @see #useProtocolVersion(int)
676 * @see java.io.ObjectStreamConstants#PROTOCOL_VERSION_1
677 * @since 1.3
678 */
679 protected void writeClassDescriptor(ObjectStreamClass desc)
680 throws IOException
681 {
682 desc.writeNonProxy(this);
683 }
684
685 /**
686 * Writes a byte. This method will block until the byte is actually
687 * written.
688 *
689 * @param val the byte to be written to the stream
690 * @throws IOException If an I/O error has occurred.
691 */
692 public void write(int val) throws IOException {
693 bout.write(val);
694 }
695
696 /**
697 * Writes an array of bytes. This method will block until the bytes are
698 * actually written.
699 *
700 * @param buf the data to be written
701 * @throws IOException If an I/O error has occurred.
702 */
703 public void write(byte[] buf) throws IOException {
704 bout.write(buf, 0, buf.length, false);
705 }
706
707 /**
708 * Writes a sub array of bytes.
709 *
710 * @param buf the data to be written
711 * @param off the start offset in the data
712 * @param len the number of bytes that are written
713 * @throws IOException If an I/O error has occurred.
714 */
715 public void write(byte[] buf, int off, int len) throws IOException {
716 if (buf == null) {
717 throw new NullPointerException();
718 }
719 Objects.checkFromIndexSize(off, len, buf.length);
720 bout.write(buf, off, len, false);
721 }
722
723 /**
724 * Flushes the stream. This will write any buffered output bytes and flush
725 * through to the underlying stream.
726 *
727 * @throws IOException If an I/O error has occurred.
728 */
729 public void flush() throws IOException {
730 bout.flush();
731 }
732
733 /**
734 * Drain any buffered data in ObjectOutputStream. Similar to flush but
735 * does not propagate the flush to the underlying stream.
736 *
737 * @throws IOException if I/O errors occur while writing to the underlying
738 * stream
739 */
740 protected void drain() throws IOException {
741 bout.drain();
742 }
743
744 /**
745 * Closes the stream. This method must be called to release any resources
746 * associated with the stream.
747 *
748 * @throws IOException If an I/O error has occurred.
749 */
750 public void close() throws IOException {
751 flush();
752 clear();
753 bout.close();
754 }
755
756 /**
757 * Writes a boolean.
758 *
759 * @param val the boolean to be written
760 * @throws IOException if I/O errors occur while writing to the underlying
761 * stream
762 */
763 public void writeBoolean(boolean val) throws IOException {
764 bout.writeBoolean(val);
765 }
766
767 /**
768 * Writes an 8 bit byte.
769 *
770 * @param val the byte value to be written
771 * @throws IOException if I/O errors occur while writing to the underlying
772 * stream
773 */
774 public void writeByte(int val) throws IOException {
775 bout.writeByte(val);
776 }
777
778 /**
779 * Writes a 16 bit short.
780 *
781 * @param val the short value to be written
782 * @throws IOException if I/O errors occur while writing to the underlying
783 * stream
784 */
785 public void writeShort(int val) throws IOException {
786 bout.writeShort(val);
787 }
788
789 /**
790 * Writes a 16 bit char.
791 *
792 * @param val the char value to be written
793 * @throws IOException if I/O errors occur while writing to the underlying
794 * stream
795 */
796 public void writeChar(int val) throws IOException {
797 bout.writeChar(val);
798 }
799
800 /**
801 * Writes a 32 bit int.
802 *
803 * @param val the integer value to be written
804 * @throws IOException if I/O errors occur while writing to the underlying
805 * stream
806 */
807 public void writeInt(int val) throws IOException {
808 bout.writeInt(val);
809 }
810
811 /**
812 * Writes a 64 bit long.
813 *
814 * @param val the long value to be written
815 * @throws IOException if I/O errors occur while writing to the underlying
816 * stream
817 */
818 public void writeLong(long val) throws IOException {
819 bout.writeLong(val);
820 }
821
822 /**
823 * Writes a 32 bit float.
824 *
825 * @param val the float value to be written
826 * @throws IOException if I/O errors occur while writing to the underlying
827 * stream
828 */
829 public void writeFloat(float val) throws IOException {
830 bout.writeFloat(val);
831 }
832
833 /**
834 * Writes a 64 bit double.
835 *
836 * @param val the double value to be written
837 * @throws IOException if I/O errors occur while writing to the underlying
838 * stream
839 */
840 public void writeDouble(double val) throws IOException {
841 bout.writeDouble(val);
842 }
843
844 /**
845 * Writes a String as a sequence of bytes.
846 *
847 * @param str the String of bytes to be written
848 * @throws IOException if I/O errors occur while writing to the underlying
849 * stream
850 */
851 public void writeBytes(String str) throws IOException {
852 bout.writeBytes(str);
853 }
854
855 /**
856 * Writes a String as a sequence of chars.
857 *
858 * @param str the String of chars to be written
859 * @throws IOException if I/O errors occur while writing to the underlying
860 * stream
861 */
862 public void writeChars(String str) throws IOException {
863 bout.writeChars(str);
864 }
865
866 /**
867 * Primitive data write of this String in
868 * <a href="DataInput.html#modified-utf-8">modified UTF-8</a>
869 * format. Note that there is a
870 * significant difference between writing a String into the stream as
871 * primitive data or as an Object. A String instance written by writeObject
872 * is written into the stream as a String initially. Future writeObject()
873 * calls write references to the string into the stream.
874 *
875 * @param str the String to be written
876 * @throws IOException if I/O errors occur while writing to the underlying
877 * stream
878 */
879 public void writeUTF(String str) throws IOException {
880 bout.writeUTF(str);
881 }
882
883 /**
884 * Provide programmatic access to the persistent fields to be written
885 * to ObjectOutput.
886 *
887 * @since 1.2
888 */
889 public abstract static class PutField {
890 /**
891 * Constructor for subclasses to call.
892 */
893 public PutField() {}
894
895 /**
896 * Put the value of the named boolean field into the persistent field.
897 *
898 * @param name the name of the serializable field
899 * @param val the value to assign to the field
900 * @throws IllegalArgumentException if {@code name} does not
901 * match the name of a serializable field for the class whose fields
902 * are being written, or if the type of the named field is not
903 * {@code boolean}
904 */
905 public abstract void put(String name, boolean val);
906
907 /**
908 * Put the value of the named byte field into the persistent field.
909 *
910 * @param name the name of the serializable field
911 * @param val the value to assign to the field
912 * @throws IllegalArgumentException if {@code name} does not
913 * match the name of a serializable field for the class whose fields
914 * are being written, or if the type of the named field is not
915 * {@code byte}
916 */
917 public abstract void put(String name, byte val);
918
919 /**
920 * Put the value of the named char field into the persistent field.
921 *
922 * @param name the name of the serializable field
923 * @param val the value to assign to the field
924 * @throws IllegalArgumentException if {@code name} does not
925 * match the name of a serializable field for the class whose fields
926 * are being written, or if the type of the named field is not
927 * {@code char}
928 */
929 public abstract void put(String name, char val);
930
931 /**
932 * Put the value of the named short field into the persistent field.
933 *
934 * @param name the name of the serializable field
935 * @param val the value to assign to the field
936 * @throws IllegalArgumentException if {@code name} does not
937 * match the name of a serializable field for the class whose fields
938 * are being written, or if the type of the named field is not
939 * {@code short}
940 */
941 public abstract void put(String name, short val);
942
943 /**
944 * Put the value of the named int field into the persistent field.
945 *
946 * @param name the name of the serializable field
947 * @param val the value to assign to the field
948 * @throws IllegalArgumentException if {@code name} does not
949 * match the name of a serializable field for the class whose fields
950 * are being written, or if the type of the named field is not
951 * {@code int}
952 */
953 public abstract void put(String name, int val);
954
955 /**
956 * Put the value of the named long field into the persistent field.
957 *
958 * @param name the name of the serializable field
959 * @param val the value to assign to the field
960 * @throws IllegalArgumentException if {@code name} does not
961 * match the name of a serializable field for the class whose fields
962 * are being written, or if the type of the named field is not
963 * {@code long}
964 */
965 public abstract void put(String name, long val);
966
967 /**
968 * Put the value of the named float field into the persistent field.
969 *
970 * @param name the name of the serializable field
971 * @param val the value to assign to the field
972 * @throws IllegalArgumentException if {@code name} does not
973 * match the name of a serializable field for the class whose fields
974 * are being written, or if the type of the named field is not
975 * {@code float}
976 */
977 public abstract void put(String name, float val);
978
979 /**
980 * Put the value of the named double field into the persistent field.
981 *
982 * @param name the name of the serializable field
983 * @param val the value to assign to the field
984 * @throws IllegalArgumentException if {@code name} does not
985 * match the name of a serializable field for the class whose fields
986 * are being written, or if the type of the named field is not
987 * {@code double}
988 */
989 public abstract void put(String name, double val);
990
991 /**
992 * Put the value of the named Object field into the persistent field.
993 *
994 * @param name the name of the serializable field
995 * @param val the value to assign to the field
996 * (which may be {@code null})
997 * @throws IllegalArgumentException if {@code name} does not
998 * match the name of a serializable field for the class whose fields
999 * are being written, or if the type of the named field is not a
1000 * reference type
1001 */
1002 public abstract void put(String name, Object val);
1003
1004 /**
1005 * Write the data and fields to the specified ObjectOutput stream,
1006 * which must be the same stream that produced this
1007 * {@code PutField} object.
1008 *
1009 * @param out the stream to write the data and fields to
1010 * @throws IOException if I/O errors occur while writing to the
1011 * underlying stream
1012 * @throws IllegalArgumentException if the specified stream is not
1013 * the same stream that produced this {@code PutField}
1014 * object
1015 * @deprecated This method does not write the values contained by this
1016 * {@code PutField} object in a proper format, and may
1017 * result in corruption of the serialization stream. The
1018 * correct way to write {@code PutField} data is by
1019 * calling the {@link java.io.ObjectOutputStream#writeFields()}
1020 * method.
1021 */
1022 @Deprecated
1023 public abstract void write(ObjectOutput out) throws IOException;
1024 }
1025
1026
1027 /**
1028 * Returns protocol version in use.
1029 */
1030 int getProtocolVersion() {
1031 return protocol;
1032 }
1033
1034 /**
1035 * Writes string without allowing it to be replaced in stream. Used by
1036 * ObjectStreamClass to write class descriptor type strings.
1037 */
1038 void writeTypeString(String str) throws IOException {
1039 int handle;
1040 if (str == null) {
1041 writeNull();
1042 } else if ((handle = handles.lookup(str)) != -1) {
1043 writeHandle(handle);
1044 } else {
1045 writeString(str, false);
1046 }
1047 }
1048
1049 /**
1050 * Verifies that this (possibly subclass) instance can be constructed
1051 * without violating security constraints: the subclass must not override
1052 * security-sensitive non-final methods, or else the
1053 * "enableSubclassImplementation" SerializablePermission is checked.
1054 */
1055 private void verifySubclass() {
1056 Class<?> cl = getClass();
1057 if (cl == ObjectOutputStream.class) {
1058 return;
1059 }
1060 @SuppressWarnings("removal")
1061 SecurityManager sm = System.getSecurityManager();
1062 if (sm == null) {
1063 return;
1064 }
1065 boolean result = Caches.subclassAudits.get(cl);
1066 if (!result) {
1067 sm.checkPermission(SUBCLASS_IMPLEMENTATION_PERMISSION);
1068 }
1069 }
1070
1071 /**
1072 * Performs reflective checks on given subclass to verify that it doesn't
1073 * override security-sensitive non-final methods. Returns TRUE if subclass
1074 * is "safe", FALSE otherwise.
1075 */
1076 @SuppressWarnings("removal")
1077 private static Boolean auditSubclass(Class<?> subcl) {
1078 return AccessController.doPrivileged(
1079 new PrivilegedAction<>() {
1080 public Boolean run() {
1081 for (Class<?> cl = subcl;
1082 cl != ObjectOutputStream.class;
1083 cl = cl.getSuperclass())
1084 {
1085 try {
1086 cl.getDeclaredMethod(
1087 "writeUnshared", new Class<?>[] { Object.class });
1088 return Boolean.FALSE;
1089 } catch (NoSuchMethodException ex) {
1090 }
1091 try {
1092 cl.getDeclaredMethod("putFields", (Class<?>[]) null);
1093 return Boolean.FALSE;
1094 } catch (NoSuchMethodException ex) {
1095 }
1096 }
1097 return Boolean.TRUE;
1098 }
1099 }
1100 );
1101 }
1102
1103 /**
1104 * Clears internal data structures.
1105 */
1106 private void clear() {
1107 subs.clear();
1108 handles.clear();
1109 }
1110
1111 /**
1112 * Underlying writeObject/writeUnshared implementation.
1113 */
1114 private void writeObject0(Object obj, boolean unshared)
1115 throws IOException
1116 {
1117 boolean oldMode = bout.setBlockDataMode(false);
1118 depth++;
1119 try {
1120 // handle previously written and non-replaceable objects
1121 int h;
1122 if ((obj = subs.lookup(obj)) == null) {
1123 writeNull();
1124 return;
1125 } else if (!unshared && (h = handles.lookup(obj)) != -1) {
1126 writeHandle(h);
1127 return;
1128 } else if (obj instanceof Class) {
1129 writeClass((Class) obj, unshared);
1130 return;
1131 } else if (obj instanceof ObjectStreamClass) {
1132 writeClassDesc((ObjectStreamClass) obj, unshared);
1133 return;
1134 }
1135
1136 // check for replacement object
1137 Object orig = obj;
1138 Class<?> cl = obj.getClass();
1139 ObjectStreamClass desc;
1140 for (;;) {
1141 // REMIND: skip this check for strings/arrays?
1142 Class<?> repCl;
1143 desc = ObjectStreamClass.lookup(cl, true);
1144 if (!desc.hasWriteReplaceMethod() ||
1145 (obj = desc.invokeWriteReplace(obj)) == null ||
1146 (repCl = obj.getClass()) == cl)
1147 {
1148 break;
1149 }
1150 cl = repCl;
1151 }
1152 if (enableReplace) {
1153 Object rep = replaceObject(obj);
1154 if (rep != obj && rep != null) {
1155 cl = rep.getClass();
1156 desc = ObjectStreamClass.lookup(cl, true);
1157 }
1158 obj = rep;
1159 }
1160
1161 // if object replaced, run through original checks a second time
1162 if (obj != orig) {
1163 subs.assign(orig, obj);
1164 if (obj == null) {
1165 writeNull();
1166 return;
1167 } else if (!unshared && (h = handles.lookup(obj)) != -1) {
1168 writeHandle(h);
1169 return;
1170 } else if (obj instanceof Class) {
1171 writeClass((Class) obj, unshared);
1172 return;
1173 } else if (obj instanceof ObjectStreamClass) {
1174 writeClassDesc((ObjectStreamClass) obj, unshared);
1175 return;
1176 }
1177 }
1178
1179 // remaining cases
1180 if (obj instanceof String) {
1181 writeString((String) obj, unshared);
1182 } else if (cl.isValue()) {
1183 throw new NotSerializableException(cl.getName());
1184 } else if (cl.isArray()) {
1185 writeArray(obj, desc, unshared);
1186 } else if (obj instanceof Enum) {
1187 writeEnum((Enum<?>) obj, desc, unshared);
1188 } else if (obj instanceof Serializable) {
1189 writeOrdinaryObject(obj, desc, unshared);
1190 } else {
1191 if (extendedDebugInfo) {
1192 throw new NotSerializableException(
1193 cl.getName() + "\n" + debugInfoStack.toString());
1194 } else {
1195 throw new NotSerializableException(cl.getName());
1196 }
1197 }
1198 } finally {
1199 depth--;
1200 bout.setBlockDataMode(oldMode);
1201 }
1202 }
1203
1204 /**
1205 * Writes null code to stream.
1206 */
1207 private void writeNull() throws IOException {
1208 bout.writeByte(TC_NULL);
1209 }
1210
1211 /**
1212 * Writes given object handle to stream.
1213 */
1214 private void writeHandle(int handle) throws IOException {
1215 bout.writeByte(TC_REFERENCE);
1216 bout.writeInt(baseWireHandle + handle);
1217 }
1218
1219 /**
1220 * Writes representation of given class to stream.
1221 */
1222 private void writeClass(Class<?> cl, boolean unshared) throws IOException {
1223 bout.writeByte(TC_CLASS);
1224 writeClassDesc(ObjectStreamClass.lookup(cl, true), false);
1225 handles.assign(unshared ? null : cl);
1226 }
1227
1228 /**
1229 * Writes representation of given class descriptor to stream.
1230 */
1231 private void writeClassDesc(ObjectStreamClass desc, boolean unshared)
1232 throws IOException
1233 {
1234 int handle;
1235 if (desc == null) {
1236 writeNull();
1237 } else if (!unshared && (handle = handles.lookup(desc)) != -1) {
1238 writeHandle(handle);
1239 } else if (desc.isProxy()) {
1240 writeProxyDesc(desc, unshared);
1241 } else {
1242 writeNonProxyDesc(desc, unshared);
1243 }
1244 }
1245
1246 private boolean isCustomSubclass() {
1247 // Return true if this class is a custom subclass of ObjectOutputStream
1248 return getClass().getClassLoader()
1249 != ObjectOutputStream.class.getClassLoader();
1250 }
1251
1252 /**
1253 * Writes class descriptor representing a dynamic proxy class to stream.
1254 */
1255 private void writeProxyDesc(ObjectStreamClass desc, boolean unshared)
1256 throws IOException
1257 {
1258 bout.writeByte(TC_PROXYCLASSDESC);
1259 handles.assign(unshared ? null : desc);
1260
1261 Class<?> cl = desc.forClass();
1262 Class<?>[] ifaces = cl.getInterfaces();
1263 bout.writeInt(ifaces.length);
1264 for (int i = 0; i < ifaces.length; i++) {
1265 bout.writeUTF(ifaces[i].getName());
1266 }
1267
1268 bout.setBlockDataMode(true);
1269 if (cl != null && isCustomSubclass()) {
1270 ReflectUtil.checkPackageAccess(cl);
1271 }
1272 annotateProxyClass(cl);
1273 bout.setBlockDataMode(false);
1274 bout.writeByte(TC_ENDBLOCKDATA);
1275
1276 writeClassDesc(desc.getSuperDesc(), false);
1277 }
1278
1279 /**
1280 * Writes class descriptor representing a standard (i.e., not a dynamic
1281 * proxy) class to stream.
1282 */
1283 private void writeNonProxyDesc(ObjectStreamClass desc, boolean unshared)
1284 throws IOException
1285 {
1286 bout.writeByte(TC_CLASSDESC);
1287 handles.assign(unshared ? null : desc);
1288
1289 if (protocol == PROTOCOL_VERSION_1) {
1290 // do not invoke class descriptor write hook with old protocol
1291 desc.writeNonProxy(this);
1292 } else {
1293 writeClassDescriptor(desc);
1294 }
1295
1296 Class<?> cl = desc.forClass();
1297 bout.setBlockDataMode(true);
1298 if (cl != null && isCustomSubclass()) {
1299 ReflectUtil.checkPackageAccess(cl);
1300 }
1301 annotateClass(cl);
1302 bout.setBlockDataMode(false);
1303 bout.writeByte(TC_ENDBLOCKDATA);
1304
1305 writeClassDesc(desc.getSuperDesc(), false);
1306 }
1307
1308 /**
1309 * Writes given string to stream, using standard or long UTF format
1310 * depending on string length.
1311 */
1312 private void writeString(String str, boolean unshared) throws IOException {
1313 handles.assign(unshared ? null : str);
1314 long utflen = bout.getUTFLength(str);
1315 if (utflen <= 0xFFFF) {
1316 bout.writeByte(TC_STRING);
1317 bout.writeUTF(str, utflen);
1318 } else {
1319 bout.writeByte(TC_LONGSTRING);
1320 bout.writeLongUTF(str, utflen);
1321 }
1322 }
1323
1324 /**
1325 * Writes given array object to stream.
1326 */
1327 private void writeArray(Object array,
1328 ObjectStreamClass desc,
1329 boolean unshared)
1330 throws IOException
1331 {
1332 bout.writeByte(TC_ARRAY);
1333 writeClassDesc(desc, false);
1334 handles.assign(unshared ? null : array);
1335
1336 Class<?> ccl = desc.forClass().getComponentType();
1337 if (ccl.isPrimitive()) {
1338 if (ccl == Integer.TYPE) {
1339 int[] ia = (int[]) array;
1340 bout.writeInt(ia.length);
1341 bout.writeInts(ia, 0, ia.length);
1342 } else if (ccl == Byte.TYPE) {
1343 byte[] ba = (byte[]) array;
1344 bout.writeInt(ba.length);
1345 bout.write(ba, 0, ba.length, true);
1346 } else if (ccl == Long.TYPE) {
1347 long[] ja = (long[]) array;
1348 bout.writeInt(ja.length);
1349 bout.writeLongs(ja, 0, ja.length);
1350 } else if (ccl == Float.TYPE) {
1351 float[] fa = (float[]) array;
1352 bout.writeInt(fa.length);
1353 bout.writeFloats(fa, 0, fa.length);
1354 } else if (ccl == Double.TYPE) {
1355 double[] da = (double[]) array;
1356 bout.writeInt(da.length);
1357 bout.writeDoubles(da, 0, da.length);
1358 } else if (ccl == Short.TYPE) {
1359 short[] sa = (short[]) array;
1360 bout.writeInt(sa.length);
1361 bout.writeShorts(sa, 0, sa.length);
1362 } else if (ccl == Character.TYPE) {
1363 char[] ca = (char[]) array;
1364 bout.writeInt(ca.length);
1365 bout.writeChars(ca, 0, ca.length);
1366 } else if (ccl == Boolean.TYPE) {
1367 boolean[] za = (boolean[]) array;
1368 bout.writeInt(za.length);
1369 bout.writeBooleans(za, 0, za.length);
1370 } else {
1371 throw new InternalError();
1372 }
1373 } else {
1374 Object[] objs = (Object[]) array;
1375 int len = objs.length;
1376 bout.writeInt(len);
1377 if (extendedDebugInfo) {
1378 debugInfoStack.push(
1379 "array (class \"" + array.getClass().getName() +
1380 "\", size: " + len + ")");
1381 }
1382 try {
1383 for (int i = 0; i < len; i++) {
1384 if (extendedDebugInfo) {
1385 debugInfoStack.push(
1386 "element of array (index: " + i + ")");
1387 }
1388 try {
1389 writeObject0(objs[i], false);
1390 } finally {
1391 if (extendedDebugInfo) {
1392 debugInfoStack.pop();
1393 }
1394 }
1395 }
1396 } finally {
1397 if (extendedDebugInfo) {
1398 debugInfoStack.pop();
1399 }
1400 }
1401 }
1402 }
1403
1404 /**
1405 * Writes given enum constant to stream.
1406 */
1407 private void writeEnum(Enum<?> en,
1408 ObjectStreamClass desc,
1409 boolean unshared)
1410 throws IOException
1411 {
1412 bout.writeByte(TC_ENUM);
1413 ObjectStreamClass sdesc = desc.getSuperDesc();
1414 writeClassDesc((sdesc.forClass() == Enum.class) ? desc : sdesc, false);
1415 handles.assign(unshared ? null : en);
1416 writeString(en.name(), false);
1417 }
1418
1419 /**
1420 * Writes representation of an "ordinary" (i.e., not a String, Class,
1421 * ObjectStreamClass, array, or enum constant) serializable object to the
1422 * stream.
1423 */
1424 private void writeOrdinaryObject(Object obj,
1425 ObjectStreamClass desc,
1426 boolean unshared)
1427 throws IOException
1428 {
1429 if (extendedDebugInfo) {
1430 debugInfoStack.push(
1431 (depth == 1 ? "root " : "") + "object (class \"" +
1432 obj.getClass().getName() + "\", " + obj.toString() + ")");
1433 }
1434 try {
1435 desc.checkSerialize();
1436
1437 bout.writeByte(TC_OBJECT);
1438 writeClassDesc(desc, false);
1439 handles.assign(unshared ? null : obj);
1440
1441 if (desc.isRecord()) {
1442 writeRecordData(obj, desc);
1443 } else if (desc.isExternalizable() && !desc.isProxy()) {
1444 writeExternalData((Externalizable) obj);
1445 } else {
1446 writeSerialData(obj, desc);
1447 }
1448 } finally {
1449 if (extendedDebugInfo) {
1450 debugInfoStack.pop();
1451 }
1452 }
1453 }
1454
1455 /**
1456 * Writes externalizable data of given object by invoking its
1457 * writeExternal() method.
1458 */
1459 private void writeExternalData(Externalizable obj) throws IOException {
1460 PutFieldImpl oldPut = curPut;
1461 curPut = null;
1462
1463 if (extendedDebugInfo) {
1464 debugInfoStack.push("writeExternal data");
1465 }
1466 SerialCallbackContext oldContext = curContext;
1467 try {
1468 curContext = null;
1469 if (protocol == PROTOCOL_VERSION_1) {
1470 obj.writeExternal(this);
1471 } else {
1472 bout.setBlockDataMode(true);
1473 obj.writeExternal(this);
1474 bout.setBlockDataMode(false);
1475 bout.writeByte(TC_ENDBLOCKDATA);
1476 }
1477 } finally {
1478 curContext = oldContext;
1479 if (extendedDebugInfo) {
1480 debugInfoStack.pop();
1481 }
1482 }
1483
1484 curPut = oldPut;
1485 }
1486
1487 /** Writes the record component values for the given record object. */
1488 private void writeRecordData(Object obj, ObjectStreamClass desc)
1489 throws IOException
1490 {
1491 assert obj.getClass().isRecord();
1492 ObjectStreamClass.ClassDataSlot[] slots = desc.getClassDataLayout();
1493 if (slots.length != 1) {
1494 throw new InvalidClassException(
1495 "expected a single record slot length, but found: " + slots.length);
1496 }
1497
1498 defaultWriteFields(obj, desc); // #### seems unnecessary to use the accessors
1499 }
1500
1501 /**
1502 * Writes instance data for each serializable class of given object, from
1503 * superclass to subclass.
1504 */
1505 private void writeSerialData(Object obj, ObjectStreamClass desc)
1506 throws IOException
1507 {
1508 ObjectStreamClass.ClassDataSlot[] slots = desc.getClassDataLayout();
1509 for (int i = 0; i < slots.length; i++) {
1510 ObjectStreamClass slotDesc = slots[i].desc;
1511 if (slotDesc.hasWriteObjectMethod()) {
1512 PutFieldImpl oldPut = curPut;
1513 curPut = null;
1514 SerialCallbackContext oldContext = curContext;
1515
1516 if (extendedDebugInfo) {
1517 debugInfoStack.push(
1518 "custom writeObject data (class \"" +
1519 slotDesc.getName() + "\")");
1520 }
1521 try {
1522 curContext = new SerialCallbackContext(obj, slotDesc);
1523 bout.setBlockDataMode(true);
1524 slotDesc.invokeWriteObject(obj, this);
1525 bout.setBlockDataMode(false);
1526 bout.writeByte(TC_ENDBLOCKDATA);
1527 } finally {
1528 curContext.setUsed();
1529 curContext = oldContext;
1530 if (extendedDebugInfo) {
1531 debugInfoStack.pop();
1532 }
1533 }
1534
1535 curPut = oldPut;
1536 } else {
1537 defaultWriteFields(obj, slotDesc);
1538 }
1539 }
1540 }
1541
1542 /**
1543 * Fetches and writes values of serializable fields of given object to
1544 * stream. The given class descriptor specifies which field values to
1545 * write, and in which order they should be written.
1546 */
1547 private void defaultWriteFields(Object obj, ObjectStreamClass desc)
1548 throws IOException
1549 {
1550 Class<?> cl = desc.forClass();
1551 if (cl != null && obj != null && !cl.isInstance(obj)) {
1552 throw new ClassCastException();
1553 }
1554
1555 desc.checkDefaultSerialize();
1556
1557 int primDataSize = desc.getPrimDataSize();
1558 if (primDataSize > 0) {
1559 if (primVals == null || primVals.length < primDataSize) {
1560 primVals = new byte[primDataSize];
1561 }
1562 desc.getPrimFieldValues(obj, primVals);
1563 bout.write(primVals, 0, primDataSize, false);
1564 }
1565
1566 int numObjFields = desc.getNumObjFields();
1567 if (numObjFields > 0) {
1568 ObjectStreamField[] fields = desc.getFields(false);
1569 Object[] objVals = new Object[numObjFields];
1570 int numPrimFields = fields.length - objVals.length;
1571 desc.getObjFieldValues(obj, objVals);
1572 for (int i = 0; i < objVals.length; i++) {
1573 if (extendedDebugInfo) {
1574 debugInfoStack.push(
1575 "field (class \"" + desc.getName() + "\", name: \"" +
1576 fields[numPrimFields + i].getName() + "\", type: \"" +
1577 fields[numPrimFields + i].getType() + "\")");
1578 }
1579 try {
1580 writeObject0(objVals[i],
1581 fields[numPrimFields + i].isUnshared());
1582 } finally {
1583 if (extendedDebugInfo) {
1584 debugInfoStack.pop();
1585 }
1586 }
1587 }
1588 }
1589 }
1590
1591 /**
1592 * Attempts to write to stream fatal IOException that has caused
1593 * serialization to abort.
1594 */
1595 private void writeFatalException(IOException ex) throws IOException {
1596 /*
1597 * Note: the serialization specification states that if a second
1598 * IOException occurs while attempting to serialize the original fatal
1599 * exception to the stream, then a StreamCorruptedException should be
1600 * thrown (section 2.1). However, due to a bug in previous
1601 * implementations of serialization, StreamCorruptedExceptions were
1602 * rarely (if ever) actually thrown--the "root" exceptions from
1603 * underlying streams were thrown instead. This historical behavior is
1604 * followed here for consistency.
1605 */
1606 clear();
1607 boolean oldMode = bout.setBlockDataMode(false);
1608 try {
1609 bout.writeByte(TC_EXCEPTION);
1610 writeObject0(ex, false);
1611 clear();
1612 } finally {
1613 bout.setBlockDataMode(oldMode);
1614 }
1615 }
1616
1617 /**
1618 * Default PutField implementation.
1619 */
1620 private class PutFieldImpl extends PutField {
1621
1622 /** class descriptor describing serializable fields */
1623 private final ObjectStreamClass desc;
1624 /** primitive field values */
1625 private final byte[] primVals;
1626 /** object field values */
1627 private final Object[] objVals;
1628
1629 /**
1630 * Creates PutFieldImpl object for writing fields defined in given
1631 * class descriptor.
1632 */
1633 PutFieldImpl(ObjectStreamClass desc) {
1634 this.desc = desc;
1635 primVals = new byte[desc.getPrimDataSize()];
1636 objVals = new Object[desc.getNumObjFields()];
1637 }
1638
1639 public void put(String name, boolean val) {
1640 Bits.putBoolean(primVals, getFieldOffset(name, Boolean.TYPE), val);
1641 }
1642
1643 public void put(String name, byte val) {
1644 primVals[getFieldOffset(name, Byte.TYPE)] = val;
1645 }
1646
1647 public void put(String name, char val) {
1648 Bits.putChar(primVals, getFieldOffset(name, Character.TYPE), val);
1649 }
1650
1651 public void put(String name, short val) {
1652 Bits.putShort(primVals, getFieldOffset(name, Short.TYPE), val);
1653 }
1654
1655 public void put(String name, int val) {
1656 Bits.putInt(primVals, getFieldOffset(name, Integer.TYPE), val);
1657 }
1658
1659 public void put(String name, float val) {
1660 Bits.putFloat(primVals, getFieldOffset(name, Float.TYPE), val);
1661 }
1662
1663 public void put(String name, long val) {
1664 Bits.putLong(primVals, getFieldOffset(name, Long.TYPE), val);
1665 }
1666
1667 public void put(String name, double val) {
1668 Bits.putDouble(primVals, getFieldOffset(name, Double.TYPE), val);
1669 }
1670
1671 public void put(String name, Object val) {
1672 objVals[getFieldOffset(name, Object.class)] = val;
1673 }
1674
1675 // deprecated in ObjectOutputStream.PutField
1676 public void write(ObjectOutput out) throws IOException {
1677 /*
1678 * Applications should *not* use this method to write PutField
1679 * data, as it will lead to stream corruption if the PutField
1680 * object writes any primitive data (since block data mode is not
1681 * unset/set properly, as is done in OOS.writeFields()). This
1682 * broken implementation is being retained solely for behavioral
1683 * compatibility, in order to support applications which use
1684 * OOS.PutField.write() for writing only non-primitive data.
1685 *
1686 * Serialization of unshared objects is not implemented here since
1687 * it is not necessary for backwards compatibility; also, unshared
1688 * semantics may not be supported by the given ObjectOutput
1689 * instance. Applications which write unshared objects using the
1690 * PutField API must use OOS.writeFields().
1691 */
1692 if (ObjectOutputStream.this != out) {
1693 throw new IllegalArgumentException("wrong stream");
1694 }
1695 out.write(primVals, 0, primVals.length);
1696
1697 ObjectStreamField[] fields = desc.getFields(false);
1698 int numPrimFields = fields.length - objVals.length;
1699 // REMIND: warn if numPrimFields > 0?
1700 for (int i = 0; i < objVals.length; i++) {
1701 if (fields[numPrimFields + i].isUnshared()) {
1702 throw new IOException("cannot write unshared object");
1703 }
1704 out.writeObject(objVals[i]);
1705 }
1706 }
1707
1708 /**
1709 * Writes buffered primitive data and object fields to stream.
1710 */
1711 void writeFields() throws IOException {
1712 bout.write(primVals, 0, primVals.length, false);
1713
1714 ObjectStreamField[] fields = desc.getFields(false);
1715 int numPrimFields = fields.length - objVals.length;
1716 for (int i = 0; i < objVals.length; i++) {
1717 if (extendedDebugInfo) {
1718 debugInfoStack.push(
1719 "field (class \"" + desc.getName() + "\", name: \"" +
1720 fields[numPrimFields + i].getName() + "\", type: \"" +
1721 fields[numPrimFields + i].getType() + "\")");
1722 }
1723 try {
1724 writeObject0(objVals[i],
1725 fields[numPrimFields + i].isUnshared());
1726 } finally {
1727 if (extendedDebugInfo) {
1728 debugInfoStack.pop();
1729 }
1730 }
1731 }
1732 }
1733
1734 /**
1735 * Returns offset of field with given name and type. A specified type
1736 * of null matches all types, Object.class matches all non-primitive
1737 * types, and any other non-null type matches assignable types only.
1738 * Throws IllegalArgumentException if no matching field found.
1739 */
1740 private int getFieldOffset(String name, Class<?> type) {
1741 ObjectStreamField field = desc.getField(name, type);
1742 if (field == null) {
1743 throw new IllegalArgumentException("no such field " + name +
1744 " with type " + type);
1745 }
1746 return field.getOffset();
1747 }
1748 }
1749
1750 /**
1751 * Buffered output stream with two modes: in default mode, outputs data in
1752 * same format as DataOutputStream; in "block data" mode, outputs data
1753 * bracketed by block data markers (see object serialization specification
1754 * for details).
1755 */
1756 private static class BlockDataOutputStream
1757 extends OutputStream implements DataOutput
1758 {
1759 /** maximum data block length */
1760 private static final int MAX_BLOCK_SIZE = 1024;
1761 /** maximum data block header length */
1762 private static final int MAX_HEADER_SIZE = 5;
1763 /** (tunable) length of char buffer (for writing strings) */
1764 private static final int CHAR_BUF_SIZE = 256;
1765
1766 /** buffer for writing general/block data */
1767 private final byte[] buf = new byte[MAX_BLOCK_SIZE];
1768 /** buffer for writing block data headers */
1769 private final byte[] hbuf = new byte[MAX_HEADER_SIZE];
1770 /** char buffer for fast string writes */
1771 private final char[] cbuf = new char[CHAR_BUF_SIZE];
1772
1773 /** block data mode */
1774 private boolean blkmode = false;
1775 /** current offset into buf */
1776 private int pos = 0;
1777
1778 /** underlying output stream */
1779 private final OutputStream out;
1780 /** loopback stream (for data writes that span data blocks) */
1781 private final DataOutputStream dout;
1782
1783 /**
1784 * Creates new BlockDataOutputStream on top of given underlying stream.
1785 * Block data mode is turned off by default.
1786 */
1787 BlockDataOutputStream(OutputStream out) {
1788 this.out = out;
1789 dout = new DataOutputStream(this);
1790 }
1791
1792 /**
1793 * Sets block data mode to the given mode (true == on, false == off)
1794 * and returns the previous mode value. If the new mode is the same as
1795 * the old mode, no action is taken. If the new mode differs from the
1796 * old mode, any buffered data is flushed before switching to the new
1797 * mode.
1798 */
1799 boolean setBlockDataMode(boolean mode) throws IOException {
1800 if (blkmode == mode) {
1801 return blkmode;
1802 }
1803 drain();
1804 blkmode = mode;
1805 return !blkmode;
1806 }
1807
1808 /**
1809 * Returns true if the stream is currently in block data mode, false
1810 * otherwise.
1811 */
1812 boolean getBlockDataMode() {
1813 return blkmode;
1814 }
1815
1816 /* ----------------- generic output stream methods ----------------- */
1817 /*
1818 * The following methods are equivalent to their counterparts in
1819 * OutputStream, except that they partition written data into data
1820 * blocks when in block data mode.
1821 */
1822
1823 public void write(int b) throws IOException {
1824 if (pos >= MAX_BLOCK_SIZE) {
1825 drain();
1826 }
1827 buf[pos++] = (byte) b;
1828 }
1829
1830 public void write(byte[] b) throws IOException {
1831 write(b, 0, b.length, false);
1832 }
1833
1834 public void write(byte[] b, int off, int len) throws IOException {
1835 write(b, off, len, false);
1836 }
1837
1838 public void flush() throws IOException {
1839 drain();
1840 out.flush();
1841 }
1842
1843 public void close() throws IOException {
1844 flush();
1845 out.close();
1846 }
1847
1848 /**
1849 * Writes specified span of byte values from given array. If copy is
1850 * true, copies the values to an intermediate buffer before writing
1851 * them to underlying stream (to avoid exposing a reference to the
1852 * original byte array).
1853 */
1854 void write(byte[] b, int off, int len, boolean copy)
1855 throws IOException
1856 {
1857 if (!(copy || blkmode)) { // write directly
1858 drain();
1859 out.write(b, off, len);
1860 return;
1861 }
1862
1863 while (len > 0) {
1864 if (pos >= MAX_BLOCK_SIZE) {
1865 drain();
1866 }
1867 if (len >= MAX_BLOCK_SIZE && !copy && pos == 0) {
1868 // avoid unnecessary copy
1869 writeBlockHeader(MAX_BLOCK_SIZE);
1870 out.write(b, off, MAX_BLOCK_SIZE);
1871 off += MAX_BLOCK_SIZE;
1872 len -= MAX_BLOCK_SIZE;
1873 } else {
1874 int wlen = Math.min(len, MAX_BLOCK_SIZE - pos);
1875 System.arraycopy(b, off, buf, pos, wlen);
1876 pos += wlen;
1877 off += wlen;
1878 len -= wlen;
1879 }
1880 }
1881 }
1882
1883 /**
1884 * Writes all buffered data from this stream to the underlying stream,
1885 * but does not flush underlying stream.
1886 */
1887 void drain() throws IOException {
1888 if (pos == 0) {
1889 return;
1890 }
1891 if (blkmode) {
1892 writeBlockHeader(pos);
1893 }
1894 out.write(buf, 0, pos);
1895 pos = 0;
1896 }
1897
1898 /**
1899 * Writes block data header. Data blocks shorter than 256 bytes are
1900 * prefixed with a 2-byte header; all others start with a 5-byte
1901 * header.
1902 */
1903 private void writeBlockHeader(int len) throws IOException {
1904 if (len <= 0xFF) {
1905 hbuf[0] = TC_BLOCKDATA;
1906 hbuf[1] = (byte) len;
1907 out.write(hbuf, 0, 2);
1908 } else {
1909 hbuf[0] = TC_BLOCKDATALONG;
1910 Bits.putInt(hbuf, 1, len);
1911 out.write(hbuf, 0, 5);
1912 }
1913 }
1914
1915
1916 /* ----------------- primitive data output methods ----------------- */
1917 /*
1918 * The following methods are equivalent to their counterparts in
1919 * DataOutputStream, except that they partition written data into data
1920 * blocks when in block data mode.
1921 */
1922
1923 public void writeBoolean(boolean v) throws IOException {
1924 if (pos >= MAX_BLOCK_SIZE) {
1925 drain();
1926 }
1927 Bits.putBoolean(buf, pos++, v);
1928 }
1929
1930 public void writeByte(int v) throws IOException {
1931 if (pos >= MAX_BLOCK_SIZE) {
1932 drain();
1933 }
1934 buf[pos++] = (byte) v;
1935 }
1936
1937 public void writeChar(int v) throws IOException {
1938 if (pos + 2 <= MAX_BLOCK_SIZE) {
1939 Bits.putChar(buf, pos, (char) v);
1940 pos += 2;
1941 } else {
1942 dout.writeChar(v);
1943 }
1944 }
1945
1946 public void writeShort(int v) throws IOException {
1947 if (pos + 2 <= MAX_BLOCK_SIZE) {
1948 Bits.putShort(buf, pos, (short) v);
1949 pos += 2;
1950 } else {
1951 dout.writeShort(v);
1952 }
1953 }
1954
1955 public void writeInt(int v) throws IOException {
1956 if (pos + 4 <= MAX_BLOCK_SIZE) {
1957 Bits.putInt(buf, pos, v);
1958 pos += 4;
1959 } else {
1960 dout.writeInt(v);
1961 }
1962 }
1963
1964 public void writeFloat(float v) throws IOException {
1965 if (pos + 4 <= MAX_BLOCK_SIZE) {
1966 Bits.putFloat(buf, pos, v);
1967 pos += 4;
1968 } else {
1969 dout.writeFloat(v);
1970 }
1971 }
1972
1973 public void writeLong(long v) throws IOException {
1974 if (pos + 8 <= MAX_BLOCK_SIZE) {
1975 Bits.putLong(buf, pos, v);
1976 pos += 8;
1977 } else {
1978 dout.writeLong(v);
1979 }
1980 }
1981
1982 public void writeDouble(double v) throws IOException {
1983 if (pos + 8 <= MAX_BLOCK_SIZE) {
1984 Bits.putDouble(buf, pos, v);
1985 pos += 8;
1986 } else {
1987 dout.writeDouble(v);
1988 }
1989 }
1990
1991 public void writeBytes(String s) throws IOException {
1992 int endoff = s.length();
1993 int cpos = 0;
1994 int csize = 0;
1995 for (int off = 0; off < endoff; ) {
1996 if (cpos >= csize) {
1997 cpos = 0;
1998 csize = Math.min(endoff - off, CHAR_BUF_SIZE);
1999 s.getChars(off, off + csize, cbuf, 0);
2000 }
2001 if (pos >= MAX_BLOCK_SIZE) {
2002 drain();
2003 }
2004 int n = Math.min(csize - cpos, MAX_BLOCK_SIZE - pos);
2005 int stop = pos + n;
2006 while (pos < stop) {
2007 buf[pos++] = (byte) cbuf[cpos++];
2008 }
2009 off += n;
2010 }
2011 }
2012
2013 public void writeChars(String s) throws IOException {
2014 int endoff = s.length();
2015 for (int off = 0; off < endoff; ) {
2016 int csize = Math.min(endoff - off, CHAR_BUF_SIZE);
2017 s.getChars(off, off + csize, cbuf, 0);
2018 writeChars(cbuf, 0, csize);
2019 off += csize;
2020 }
2021 }
2022
2023 public void writeUTF(String s) throws IOException {
2024 writeUTF(s, getUTFLength(s));
2025 }
2026
2027
2028 /* -------------- primitive data array output methods -------------- */
2029 /*
2030 * The following methods write out spans of primitive data values.
2031 * Though equivalent to calling the corresponding primitive write
2032 * methods repeatedly, these methods are optimized for writing groups
2033 * of primitive data values more efficiently.
2034 */
2035
2036 void writeBooleans(boolean[] v, int off, int len) throws IOException {
2037 int endoff = off + len;
2038 while (off < endoff) {
2039 if (pos >= MAX_BLOCK_SIZE) {
2040 drain();
2041 }
2042 int stop = Math.min(endoff, off + (MAX_BLOCK_SIZE - pos));
2043 while (off < stop) {
2044 Bits.putBoolean(buf, pos++, v[off++]);
2045 }
2046 }
2047 }
2048
2049 void writeChars(char[] v, int off, int len) throws IOException {
2050 int limit = MAX_BLOCK_SIZE - 2;
2051 int endoff = off + len;
2052 while (off < endoff) {
2053 if (pos <= limit) {
2054 int avail = (MAX_BLOCK_SIZE - pos) >> 1;
2055 int stop = Math.min(endoff, off + avail);
2056 while (off < stop) {
2057 Bits.putChar(buf, pos, v[off++]);
2058 pos += 2;
2059 }
2060 } else {
2061 dout.writeChar(v[off++]);
2062 }
2063 }
2064 }
2065
2066 void writeShorts(short[] v, int off, int len) throws IOException {
2067 int limit = MAX_BLOCK_SIZE - 2;
2068 int endoff = off + len;
2069 while (off < endoff) {
2070 if (pos <= limit) {
2071 int avail = (MAX_BLOCK_SIZE - pos) >> 1;
2072 int stop = Math.min(endoff, off + avail);
2073 while (off < stop) {
2074 Bits.putShort(buf, pos, v[off++]);
2075 pos += 2;
2076 }
2077 } else {
2078 dout.writeShort(v[off++]);
2079 }
2080 }
2081 }
2082
2083 void writeInts(int[] v, int off, int len) throws IOException {
2084 int limit = MAX_BLOCK_SIZE - 4;
2085 int endoff = off + len;
2086 while (off < endoff) {
2087 if (pos <= limit) {
2088 int avail = (MAX_BLOCK_SIZE - pos) >> 2;
2089 int stop = Math.min(endoff, off + avail);
2090 while (off < stop) {
2091 Bits.putInt(buf, pos, v[off++]);
2092 pos += 4;
2093 }
2094 } else {
2095 dout.writeInt(v[off++]);
2096 }
2097 }
2098 }
2099
2100 void writeFloats(float[] v, int off, int len) throws IOException {
2101 int limit = MAX_BLOCK_SIZE - 4;
2102 int endoff = off + len;
2103 while (off < endoff) {
2104 if (pos <= limit) {
2105 int avail = (MAX_BLOCK_SIZE - pos) >> 2;
2106 int stop = Math.min(endoff, off + avail);
2107 while (off < stop) {
2108 Bits.putFloat(buf, pos, v[off++]);
2109 pos += 4;
2110 }
2111 } else {
2112 dout.writeFloat(v[off++]);
2113 }
2114 }
2115 }
2116
2117 void writeLongs(long[] v, int off, int len) throws IOException {
2118 int limit = MAX_BLOCK_SIZE - 8;
2119 int endoff = off + len;
2120 while (off < endoff) {
2121 if (pos <= limit) {
2122 int avail = (MAX_BLOCK_SIZE - pos) >> 3;
2123 int stop = Math.min(endoff, off + avail);
2124 while (off < stop) {
2125 Bits.putLong(buf, pos, v[off++]);
2126 pos += 8;
2127 }
2128 } else {
2129 dout.writeLong(v[off++]);
2130 }
2131 }
2132 }
2133
2134 void writeDoubles(double[] v, int off, int len) throws IOException {
2135 int limit = MAX_BLOCK_SIZE - 8;
2136 int endoff = off + len;
2137 while (off < endoff) {
2138 if (pos <= limit) {
2139 int avail = (MAX_BLOCK_SIZE - pos) >> 3;
2140 int stop = Math.min(endoff, off + avail);
2141 while (off < stop) {
2142 Bits.putDouble(buf, pos, v[off++]);
2143 pos += 8;
2144 }
2145 } else {
2146 dout.writeDouble(v[off++]);
2147 }
2148 }
2149 }
2150
2151 /**
2152 * Returns the length in bytes of the UTF encoding of the given string.
2153 */
2154 long getUTFLength(String s) {
2155 int len = s.length();
2156 long utflen = 0;
2157 for (int off = 0; off < len; ) {
2158 int csize = Math.min(len - off, CHAR_BUF_SIZE);
2159 s.getChars(off, off + csize, cbuf, 0);
2160 for (int cpos = 0; cpos < csize; cpos++) {
2161 char c = cbuf[cpos];
2162 if (c >= 0x0001 && c <= 0x007F) {
2163 utflen++;
2164 } else if (c > 0x07FF) {
2165 utflen += 3;
2166 } else {
2167 utflen += 2;
2168 }
2169 }
2170 off += csize;
2171 }
2172 return utflen;
2173 }
2174
2175 /**
2176 * Writes the given string in UTF format. This method is used in
2177 * situations where the UTF encoding length of the string is already
2178 * known; specifying it explicitly avoids a prescan of the string to
2179 * determine its UTF length.
2180 */
2181 void writeUTF(String s, long utflen) throws IOException {
2182 if (utflen > 0xFFFFL) {
2183 throw new UTFDataFormatException();
2184 }
2185 writeShort((int) utflen);
2186 if (utflen == (long) s.length()) {
2187 writeBytes(s);
2188 } else {
2189 writeUTFBody(s);
2190 }
2191 }
2192
2193 /**
2194 * Writes given string in "long" UTF format. "Long" UTF format is
2195 * identical to standard UTF, except that it uses an 8 byte header
2196 * (instead of the standard 2 bytes) to convey the UTF encoding length.
2197 */
2198 void writeLongUTF(String s) throws IOException {
2199 writeLongUTF(s, getUTFLength(s));
2200 }
2201
2202 /**
2203 * Writes given string in "long" UTF format, where the UTF encoding
2204 * length of the string is already known.
2205 */
2206 void writeLongUTF(String s, long utflen) throws IOException {
2207 writeLong(utflen);
2208 if (utflen == (long) s.length()) {
2209 writeBytes(s);
2210 } else {
2211 writeUTFBody(s);
2212 }
2213 }
2214
2215 /**
2216 * Writes the "body" (i.e., the UTF representation minus the 2-byte or
2217 * 8-byte length header) of the UTF encoding for the given string.
2218 */
2219 private void writeUTFBody(String s) throws IOException {
2220 int limit = MAX_BLOCK_SIZE - 3;
2221 int len = s.length();
2222 for (int off = 0; off < len; ) {
2223 int csize = Math.min(len - off, CHAR_BUF_SIZE);
2224 s.getChars(off, off + csize, cbuf, 0);
2225 for (int cpos = 0; cpos < csize; cpos++) {
2226 char c = cbuf[cpos];
2227 if (pos <= limit) {
2228 if (c <= 0x007F && c != 0) {
2229 buf[pos++] = (byte) c;
2230 } else if (c > 0x07FF) {
2231 buf[pos + 2] = (byte) (0x80 | ((c >> 0) & 0x3F));
2232 buf[pos + 1] = (byte) (0x80 | ((c >> 6) & 0x3F));
2233 buf[pos + 0] = (byte) (0xE0 | ((c >> 12) & 0x0F));
2234 pos += 3;
2235 } else {
2236 buf[pos + 1] = (byte) (0x80 | ((c >> 0) & 0x3F));
2237 buf[pos + 0] = (byte) (0xC0 | ((c >> 6) & 0x1F));
2238 pos += 2;
2239 }
2240 } else { // write one byte at a time to normalize block
2241 if (c <= 0x007F && c != 0) {
2242 write(c);
2243 } else if (c > 0x07FF) {
2244 write(0xE0 | ((c >> 12) & 0x0F));
2245 write(0x80 | ((c >> 6) & 0x3F));
2246 write(0x80 | ((c >> 0) & 0x3F));
2247 } else {
2248 write(0xC0 | ((c >> 6) & 0x1F));
2249 write(0x80 | ((c >> 0) & 0x3F));
2250 }
2251 }
2252 }
2253 off += csize;
2254 }
2255 }
2256 }
2257
2258 /**
2259 * Lightweight identity hash table which maps objects to integer handles,
2260 * assigned in ascending order.
2261 */
2262 private static class HandleTable {
2263
2264 /* number of mappings in table/next available handle */
2265 private int size;
2266 /* size threshold determining when to expand hash spine */
2267 private int threshold;
2268 /* factor for computing size threshold */
2269 private final float loadFactor;
2270 /* maps hash value -> candidate handle value */
2271 private int[] spine;
2272 /* maps handle value -> next candidate handle value */
2273 private int[] next;
2274 /* maps handle value -> associated object */
2275 private Object[] objs;
2276
2277 /**
2278 * Creates new HandleTable with given capacity and load factor.
2279 */
2280 HandleTable(int initialCapacity, float loadFactor) {
2281 this.loadFactor = loadFactor;
2282 spine = new int[initialCapacity];
2283 next = new int[initialCapacity];
2284 objs = new Object[initialCapacity];
2285 threshold = (int) (initialCapacity * loadFactor);
2286 clear();
2287 }
2288
2289 /**
2290 * Assigns next available handle to given object, and returns handle
2291 * value. Handles are assigned in ascending order starting at 0.
2292 */
2293 int assign(Object obj) {
2294 if (size >= next.length) {
2295 growEntries();
2296 }
2297 if (size >= threshold) {
2298 growSpine();
2299 }
2300 insert(obj, size);
2301 return size++;
2302 }
2303
2304 /**
2305 * Looks up and returns handle associated with given object, or -1 if
2306 * no mapping found.
2307 */
2308 int lookup(Object obj) {
2309 if (size == 0) {
2310 return -1;
2311 }
2312 int index = hash(obj) % spine.length;
2313 for (int i = spine[index]; i >= 0; i = next[i]) {
2314 if (objs[i] == obj) {
2315 return i;
2316 }
2317 }
2318 return -1;
2319 }
2320
2321 /**
2322 * Resets table to its initial (empty) state.
2323 */
2324 void clear() {
2325 Arrays.fill(spine, -1);
2326 Arrays.fill(objs, 0, size, null);
2327 size = 0;
2328 }
2329
2330 /**
2331 * Returns the number of mappings currently in table.
2332 */
2333 int size() {
2334 return size;
2335 }
2336
2337 /**
2338 * Inserts mapping object -> handle mapping into table. Assumes table
2339 * is large enough to accommodate new mapping.
2340 */
2341 private void insert(Object obj, int handle) {
2342 int index = hash(obj) % spine.length;
2343 objs[handle] = obj;
2344 next[handle] = spine[index];
2345 spine[index] = handle;
2346 }
2347
2348 /**
2349 * Expands the hash "spine" -- equivalent to increasing the number of
2350 * buckets in a conventional hash table.
2351 */
2352 private void growSpine() {
2353 spine = new int[(spine.length << 1) + 1];
2354 threshold = (int) (spine.length * loadFactor);
2355 Arrays.fill(spine, -1);
2356 for (int i = 0; i < size; i++) {
2357 insert(objs[i], i);
2358 }
2359 }
2360
2361 /**
2362 * Increases hash table capacity by lengthening entry arrays.
2363 */
2364 private void growEntries() {
2365 int newLength = (next.length << 1) + 1;
2366 int[] newNext = new int[newLength];
2367 System.arraycopy(next, 0, newNext, 0, size);
2368 next = newNext;
2369
2370 Object[] newObjs = new Object[newLength];
2371 System.arraycopy(objs, 0, newObjs, 0, size);
2372 objs = newObjs;
2373 }
2374
2375 /**
2376 * Returns hash value for given object.
2377 */
2378 private int hash(Object obj) {
2379 return System.identityHashCode(obj) & 0x7FFFFFFF;
2380 }
2381 }
2382
2383 /**
2384 * Lightweight identity hash table which maps objects to replacement
2385 * objects.
2386 */
2387 private static class ReplaceTable {
2388
2389 /* maps object -> index */
2390 private final HandleTable htab;
2391 /* maps index -> replacement object */
2392 private Object[] reps;
2393
2394 /**
2395 * Creates new ReplaceTable with given capacity and load factor.
2396 */
2397 ReplaceTable(int initialCapacity, float loadFactor) {
2398 htab = new HandleTable(initialCapacity, loadFactor);
2399 reps = new Object[initialCapacity];
2400 }
2401
2402 /**
2403 * Enters mapping from object to replacement object.
2404 */
2405 void assign(Object obj, Object rep) {
2406 int index = htab.assign(obj);
2407 while (index >= reps.length) {
2408 grow();
2409 }
2410 reps[index] = rep;
2411 }
2412
2413 /**
2414 * Looks up and returns replacement for given object. If no
2415 * replacement is found, returns the lookup object itself.
2416 */
2417 Object lookup(Object obj) {
2418 int index = htab.lookup(obj);
2419 return (index >= 0) ? reps[index] : obj;
2420 }
2421
2422 /**
2423 * Resets table to its initial (empty) state.
2424 */
2425 void clear() {
2426 Arrays.fill(reps, 0, htab.size(), null);
2427 htab.clear();
2428 }
2429
2430 /**
2431 * Returns the number of mappings currently in table.
2432 */
2433 int size() {
2434 return htab.size();
2435 }
2436
2437 /**
2438 * Increases table capacity.
2439 */
2440 private void grow() {
2441 Object[] newReps = new Object[(reps.length << 1) + 1];
2442 System.arraycopy(reps, 0, newReps, 0, reps.length);
2443 reps = newReps;
2444 }
2445 }
2446
2447 /**
2448 * Stack to keep debug information about the state of the
2449 * serialization process, for embedding in exception messages.
2450 */
2451 private static class DebugTraceInfoStack {
2452 private final List<String> stack;
2453
2454 DebugTraceInfoStack() {
2455 stack = new ArrayList<>();
2456 }
2457
2458 /**
2459 * Removes all of the elements from enclosed list.
2460 */
2461 void clear() {
2462 stack.clear();
2463 }
2464
2465 /**
2466 * Removes the object at the top of enclosed list.
2467 */
2468 void pop() {
2469 stack.remove(stack.size()-1);
2470 }
2471
2472 /**
2473 * Pushes a String onto the top of enclosed list.
2474 */
2475 void push(String entry) {
2476 stack.add("\t- " + entry);
2477 }
2478
2479 /**
2480 * Returns a string representation of this object
2481 */
2482 public String toString() {
2483 StringJoiner sj = new StringJoiner("\n");
2484 for (int i = stack.size() - 1; i >= 0; i--) {
2485 sj.add(stack.get(i));
2486 }
2487 return sj.toString();
2488 }
2489 }
2490
2491 }