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 @Override
693 public void write(int val) throws IOException {
694 bout.write(val);
695 }
696
697 /**
698 * Writes an array of bytes. This method will block until the bytes are
699 * actually written.
700 *
701 * @param buf the data to be written
702 * @throws IOException If an I/O error has occurred.
703 */
704 @Override
705 public void write(byte[] buf) throws IOException {
706 bout.write(buf, 0, buf.length, false);
707 }
708
709 /**
710 * Writes a sub array of bytes.
711 *
712 * @param buf the data to be written
713 * @param off the start offset in the data
714 * @param len the number of bytes that are written
715 * @throws IOException {@inheritDoc}
716 */
717 @Override
718 public void write(byte[] buf, int off, int len) throws IOException {
719 if (buf == null) {
720 throw new NullPointerException();
721 }
722 Objects.checkFromIndexSize(off, len, buf.length);
723 bout.write(buf, off, len, false);
724 }
725
726 /**
727 * Flushes the stream. This will write any buffered output bytes and flush
728 * through to the underlying stream.
729 *
730 * @throws IOException {@inheritDoc}
731 */
732 @Override
733 public void flush() throws IOException {
734 bout.flush();
735 }
736
737 /**
738 * Drain any buffered data in ObjectOutputStream. Similar to flush but
739 * does not propagate the flush to the underlying stream.
740 *
741 * @throws IOException if I/O errors occur while writing to the underlying
742 * stream
743 */
744 protected void drain() throws IOException {
745 bout.drain();
746 }
747
748 /**
749 * Closes the stream. This method must be called to release any resources
750 * associated with the stream.
751 *
752 * @throws IOException If an I/O error has occurred.
753 */
754 @Override
755 public void close() throws IOException {
756 flush();
757 clear();
758 bout.close();
759 }
760
761 /**
762 * Writes a boolean.
763 *
764 * @param val the boolean to be written
765 * @throws IOException if I/O errors occur while writing to the underlying
766 * stream
767 */
768 public void writeBoolean(boolean val) throws IOException {
769 bout.writeBoolean(val);
770 }
771
772 /**
773 * Writes an 8 bit byte.
774 *
775 * @param val the byte value to be written
776 * @throws IOException if I/O errors occur while writing to the underlying
777 * stream
778 */
779 public void writeByte(int val) throws IOException {
780 bout.writeByte(val);
781 }
782
783 /**
784 * Writes a 16 bit short.
785 *
786 * @param val the short value to be written
787 * @throws IOException if I/O errors occur while writing to the underlying
788 * stream
789 */
790 public void writeShort(int val) throws IOException {
791 bout.writeShort(val);
792 }
793
794 /**
795 * Writes a 16 bit char.
796 *
797 * @param val the char value to be written
798 * @throws IOException if I/O errors occur while writing to the underlying
799 * stream
800 */
801 public void writeChar(int val) throws IOException {
802 bout.writeChar(val);
803 }
804
805 /**
806 * Writes a 32 bit int.
807 *
808 * @param val the integer value to be written
809 * @throws IOException if I/O errors occur while writing to the underlying
810 * stream
811 */
812 public void writeInt(int val) throws IOException {
813 bout.writeInt(val);
814 }
815
816 /**
817 * Writes a 64 bit long.
818 *
819 * @param val the long value to be written
820 * @throws IOException if I/O errors occur while writing to the underlying
821 * stream
822 */
823 public void writeLong(long val) throws IOException {
824 bout.writeLong(val);
825 }
826
827 /**
828 * Writes a 32 bit float.
829 *
830 * @param val the float value to be written
831 * @throws IOException if I/O errors occur while writing to the underlying
832 * stream
833 */
834 public void writeFloat(float val) throws IOException {
835 bout.writeFloat(val);
836 }
837
838 /**
839 * Writes a 64 bit double.
840 *
841 * @param val the double value to be written
842 * @throws IOException if I/O errors occur while writing to the underlying
843 * stream
844 */
845 public void writeDouble(double val) throws IOException {
846 bout.writeDouble(val);
847 }
848
849 /**
850 * Writes a String as a sequence of bytes.
851 *
852 * @param str the String of bytes to be written
853 * @throws IOException if I/O errors occur while writing to the underlying
854 * stream
855 */
856 public void writeBytes(String str) throws IOException {
857 bout.writeBytes(str);
858 }
859
860 /**
861 * Writes a String as a sequence of chars.
862 *
863 * @param str the String of chars to be written
864 * @throws IOException if I/O errors occur while writing to the underlying
865 * stream
866 */
867 public void writeChars(String str) throws IOException {
868 bout.writeChars(str);
869 }
870
871 /**
872 * Primitive data write of this String in
873 * <a href="DataInput.html#modified-utf-8">modified UTF-8</a>
874 * format. Note that there is a
875 * significant difference between writing a String into the stream as
876 * primitive data or as an Object. A String instance written by writeObject
877 * is written into the stream as a String initially. Future writeObject()
878 * calls write references to the string into the stream.
879 *
880 * @param str the String to be written
881 * @throws IOException if I/O errors occur while writing to the underlying
882 * stream
883 */
884 public void writeUTF(String str) throws IOException {
885 bout.writeUTF(str);
886 }
887
888 /**
889 * Provide programmatic access to the persistent fields to be written
890 * to ObjectOutput.
891 *
892 * @since 1.2
893 */
894 public abstract static class PutField {
895 /**
896 * Constructor for subclasses to call.
897 */
898 public PutField() {}
899
900 /**
901 * Put the value of the named boolean field into the persistent field.
902 *
903 * @param name the name of the serializable field
904 * @param val the value to assign to the field
905 * @throws IllegalArgumentException if {@code name} does not
906 * match the name of a serializable field for the class whose fields
907 * are being written, or if the type of the named field is not
908 * {@code boolean}
909 */
910 public abstract void put(String name, boolean val);
911
912 /**
913 * Put the value of the named byte field into the persistent field.
914 *
915 * @param name the name of the serializable field
916 * @param val the value to assign to the field
917 * @throws IllegalArgumentException if {@code name} does not
918 * match the name of a serializable field for the class whose fields
919 * are being written, or if the type of the named field is not
920 * {@code byte}
921 */
922 public abstract void put(String name, byte val);
923
924 /**
925 * Put the value of the named char field into the persistent field.
926 *
927 * @param name the name of the serializable field
928 * @param val the value to assign to the field
929 * @throws IllegalArgumentException if {@code name} does not
930 * match the name of a serializable field for the class whose fields
931 * are being written, or if the type of the named field is not
932 * {@code char}
933 */
934 public abstract void put(String name, char val);
935
936 /**
937 * Put the value of the named short field into the persistent field.
938 *
939 * @param name the name of the serializable field
940 * @param val the value to assign to the field
941 * @throws IllegalArgumentException if {@code name} does not
942 * match the name of a serializable field for the class whose fields
943 * are being written, or if the type of the named field is not
944 * {@code short}
945 */
946 public abstract void put(String name, short val);
947
948 /**
949 * Put the value of the named int field into the persistent field.
950 *
951 * @param name the name of the serializable field
952 * @param val the value to assign to the field
953 * @throws IllegalArgumentException if {@code name} does not
954 * match the name of a serializable field for the class whose fields
955 * are being written, or if the type of the named field is not
956 * {@code int}
957 */
958 public abstract void put(String name, int val);
959
960 /**
961 * Put the value of the named long field into the persistent field.
962 *
963 * @param name the name of the serializable field
964 * @param val the value to assign to the field
965 * @throws IllegalArgumentException if {@code name} does not
966 * match the name of a serializable field for the class whose fields
967 * are being written, or if the type of the named field is not
968 * {@code long}
969 */
970 public abstract void put(String name, long val);
971
972 /**
973 * Put the value of the named float field into the persistent field.
974 *
975 * @param name the name of the serializable field
976 * @param val the value to assign to the field
977 * @throws IllegalArgumentException if {@code name} does not
978 * match the name of a serializable field for the class whose fields
979 * are being written, or if the type of the named field is not
980 * {@code float}
981 */
982 public abstract void put(String name, float val);
983
984 /**
985 * Put the value of the named double field into the persistent field.
986 *
987 * @param name the name of the serializable field
988 * @param val the value to assign to the field
989 * @throws IllegalArgumentException if {@code name} does not
990 * match the name of a serializable field for the class whose fields
991 * are being written, or if the type of the named field is not
992 * {@code double}
993 */
994 public abstract void put(String name, double val);
995
996 /**
997 * Put the value of the named Object field into the persistent field.
998 *
999 * @param name the name of the serializable field
1000 * @param val the value to assign to the field
1001 * (which may be {@code null})
1002 * @throws IllegalArgumentException if {@code name} does not
1003 * match the name of a serializable field for the class whose fields
1004 * are being written, or if the type of the named field is not a
1005 * reference type
1006 */
1007 public abstract void put(String name, Object val);
1008
1009 /**
1010 * Write the data and fields to the specified ObjectOutput stream,
1011 * which must be the same stream that produced this
1012 * {@code PutField} object.
1013 *
1014 * @param out the stream to write the data and fields to
1015 * @throws IOException if I/O errors occur while writing to the
1016 * underlying stream
1017 * @throws IllegalArgumentException if the specified stream is not
1018 * the same stream that produced this {@code PutField}
1019 * object
1020 * @deprecated This method does not write the values contained by this
1021 * {@code PutField} object in a proper format, and may
1022 * result in corruption of the serialization stream. The
1023 * correct way to write {@code PutField} data is by
1024 * calling the {@link java.io.ObjectOutputStream#writeFields()}
1025 * method.
1026 */
1027 @Deprecated
1028 public abstract void write(ObjectOutput out) throws IOException;
1029 }
1030
1031
1032 /**
1033 * Returns protocol version in use.
1034 */
1035 int getProtocolVersion() {
1036 return protocol;
1037 }
1038
1039 /**
1040 * Writes string without allowing it to be replaced in stream. Used by
1041 * ObjectStreamClass to write class descriptor type strings.
1042 */
1043 void writeTypeString(String str) throws IOException {
1044 int handle;
1045 if (str == null) {
1046 writeNull();
1047 } else if ((handle = handles.lookup(str)) != -1) {
1048 writeHandle(handle);
1049 } else {
1050 writeString(str, false);
1051 }
1052 }
1053
1054 /**
1055 * Verifies that this (possibly subclass) instance can be constructed
1056 * without violating security constraints: the subclass must not override
1057 * security-sensitive non-final methods, or else the
1058 * "enableSubclassImplementation" SerializablePermission is checked.
1059 */
1060 private void verifySubclass() {
1061 Class<?> cl = getClass();
1062 if (cl == ObjectOutputStream.class) {
1063 return;
1064 }
1065 @SuppressWarnings("removal")
1066 SecurityManager sm = System.getSecurityManager();
1067 if (sm == null) {
1068 return;
1069 }
1070 boolean result = Caches.subclassAudits.get(cl);
1071 if (!result) {
1072 sm.checkPermission(SUBCLASS_IMPLEMENTATION_PERMISSION);
1073 }
1074 }
1075
1076 /**
1077 * Performs reflective checks on given subclass to verify that it doesn't
1078 * override security-sensitive non-final methods. Returns TRUE if subclass
1079 * is "safe", FALSE otherwise.
1080 */
1081 @SuppressWarnings("removal")
1082 private static Boolean auditSubclass(Class<?> subcl) {
1083 return AccessController.doPrivileged(
1084 new PrivilegedAction<>() {
1085 public Boolean run() {
1086 for (Class<?> cl = subcl;
1087 cl != ObjectOutputStream.class;
1088 cl = cl.getSuperclass())
1089 {
1090 try {
1091 cl.getDeclaredMethod(
1092 "writeUnshared", new Class<?>[] { Object.class });
1093 return Boolean.FALSE;
1094 } catch (NoSuchMethodException ex) {
1095 }
1096 try {
1097 cl.getDeclaredMethod("putFields", (Class<?>[]) null);
1098 return Boolean.FALSE;
1099 } catch (NoSuchMethodException ex) {
1100 }
1101 }
1102 return Boolean.TRUE;
1103 }
1104 }
1105 );
1106 }
1107
1108 /**
1109 * Clears internal data structures.
1110 */
1111 private void clear() {
1112 subs.clear();
1113 handles.clear();
1114 }
1115
1116 /**
1117 * Underlying writeObject/writeUnshared implementation.
1118 */
1119 private void writeObject0(Object obj, boolean unshared)
1120 throws IOException
1121 {
1122 boolean oldMode = bout.setBlockDataMode(false);
1123 depth++;
1124 try {
1125 // handle previously written and non-replaceable objects
1126 int h;
1127 if ((obj = subs.lookup(obj)) == null) {
1128 writeNull();
1129 return;
1130 } else if (!unshared && (h = handles.lookup(obj)) != -1) {
1131 writeHandle(h);
1132 return;
1133 } else if (obj instanceof Class) {
1134 writeClass((Class) obj, unshared);
1135 return;
1136 } else if (obj instanceof ObjectStreamClass) {
1137 writeClassDesc((ObjectStreamClass) obj, unshared);
1138 return;
1139 }
1140
1141 // check for replacement object
1142 Object orig = obj;
1143 Class<?> cl = obj.getClass();
1144 ObjectStreamClass desc;
1145 for (;;) {
1146 // REMIND: skip this check for strings/arrays?
1147 Class<?> repCl;
1148 desc = ObjectStreamClass.lookup(cl, true);
1149 if (!desc.hasWriteReplaceMethod() ||
1150 (obj = desc.invokeWriteReplace(obj)) == null ||
1151 (repCl = obj.getClass()) == cl)
1152 {
1153 break;
1154 }
1155 cl = repCl;
1156 }
1157 if (enableReplace) {
1158 Object rep = replaceObject(obj);
1159 if (rep != obj && rep != null) {
1160 cl = rep.getClass();
1161 desc = ObjectStreamClass.lookup(cl, true);
1162 }
1163 obj = rep;
1164 }
1165
1166 // if object replaced, run through original checks a second time
1167 if (obj != orig) {
1168 subs.assign(orig, obj);
1169 if (obj == null) {
1170 writeNull();
1171 return;
1172 } else if (!unshared && (h = handles.lookup(obj)) != -1) {
1173 writeHandle(h);
1174 return;
1175 } else if (obj instanceof Class) {
1176 writeClass((Class) obj, unshared);
1177 return;
1178 } else if (obj instanceof ObjectStreamClass) {
1179 writeClassDesc((ObjectStreamClass) obj, unshared);
1180 return;
1181 }
1182 }
1183
1184 // remaining cases
1185 if (obj instanceof String) {
1186 writeString((String) obj, unshared);
1187 } else if (cl.isArray()) {
1188 writeArray(obj, desc, unshared);
1189 } else if (obj instanceof Enum) {
1190 writeEnum((Enum<?>) obj, desc, unshared);
1191 } else if (obj instanceof Serializable) {
1192 writeOrdinaryObject(obj, desc, unshared);
1193 } else {
1194 if (extendedDebugInfo) {
1195 throw new NotSerializableException(
1196 cl.getName() + "\n" + debugInfoStack.toString());
1197 } else {
1198 throw new NotSerializableException(cl.getName());
1199 }
1200 }
1201 } finally {
1202 depth--;
1203 bout.setBlockDataMode(oldMode);
1204 }
1205 }
1206
1207 /**
1208 * Writes null code to stream.
1209 */
1210 private void writeNull() throws IOException {
1211 bout.writeByte(TC_NULL);
1212 }
1213
1214 /**
1215 * Writes given object handle to stream.
1216 */
1217 private void writeHandle(int handle) throws IOException {
1218 bout.writeByte(TC_REFERENCE);
1219 bout.writeInt(baseWireHandle + handle);
1220 }
1221
1222 /**
1223 * Writes representation of given class to stream.
1224 */
1225 private void writeClass(Class<?> cl, boolean unshared) throws IOException {
1226 bout.writeByte(TC_CLASS);
1227 writeClassDesc(ObjectStreamClass.lookup(cl, true), false);
1228 handles.assign(unshared ? null : cl);
1229 }
1230
1231 /**
1232 * Writes representation of given class descriptor to stream.
1233 */
1234 private void writeClassDesc(ObjectStreamClass desc, boolean unshared)
1235 throws IOException
1236 {
1237 int handle;
1238 if (desc == null) {
1239 writeNull();
1240 } else if (!unshared && (handle = handles.lookup(desc)) != -1) {
1241 writeHandle(handle);
1242 } else if (desc.isProxy()) {
1243 writeProxyDesc(desc, unshared);
1244 } else {
1245 writeNonProxyDesc(desc, unshared);
1246 }
1247 }
1248
1249 private boolean isCustomSubclass() {
1250 // Return true if this class is a custom subclass of ObjectOutputStream
1251 return getClass().getClassLoader()
1252 != ObjectOutputStream.class.getClassLoader();
1253 }
1254
1255 /**
1256 * Writes class descriptor representing a dynamic proxy class to stream.
1257 */
1258 private void writeProxyDesc(ObjectStreamClass desc, boolean unshared)
1259 throws IOException
1260 {
1261 bout.writeByte(TC_PROXYCLASSDESC);
1262 handles.assign(unshared ? null : desc);
1263
1264 Class<?> cl = desc.forClass();
1265 Class<?>[] ifaces = cl.getInterfaces();
1266 bout.writeInt(ifaces.length);
1267 for (int i = 0; i < ifaces.length; i++) {
1268 bout.writeUTF(ifaces[i].getName());
1269 }
1270
1271 bout.setBlockDataMode(true);
1272 if (cl != null && isCustomSubclass()) {
1273 ReflectUtil.checkPackageAccess(cl);
1274 }
1275 annotateProxyClass(cl);
1276 bout.setBlockDataMode(false);
1277 bout.writeByte(TC_ENDBLOCKDATA);
1278
1279 writeClassDesc(desc.getSuperDesc(), false);
1280 }
1281
1282 /**
1283 * Writes class descriptor representing a standard (i.e., not a dynamic
1284 * proxy) class to stream.
1285 */
1286 private void writeNonProxyDesc(ObjectStreamClass desc, boolean unshared)
1287 throws IOException
1288 {
1289 bout.writeByte(TC_CLASSDESC);
1290 handles.assign(unshared ? null : desc);
1291
1292 if (protocol == PROTOCOL_VERSION_1) {
1293 // do not invoke class descriptor write hook with old protocol
1294 desc.writeNonProxy(this);
1295 } else {
1296 writeClassDescriptor(desc);
1297 }
1298
1299 Class<?> cl = desc.forClass();
1300 bout.setBlockDataMode(true);
1301 if (cl != null && isCustomSubclass()) {
1302 ReflectUtil.checkPackageAccess(cl);
1303 }
1304 annotateClass(cl);
1305 bout.setBlockDataMode(false);
1306 bout.writeByte(TC_ENDBLOCKDATA);
1307
1308 writeClassDesc(desc.getSuperDesc(), false);
1309 }
1310
1311 /**
1312 * Writes given string to stream, using standard or long UTF format
1313 * depending on string length.
1314 */
1315 private void writeString(String str, boolean unshared) throws IOException {
1316 handles.assign(unshared ? null : str);
1317 long utflen = bout.getUTFLength(str);
1318 if (utflen <= 0xFFFF) {
1319 bout.writeByte(TC_STRING);
1320 bout.writeUTF(str, utflen);
1321 } else {
1322 bout.writeByte(TC_LONGSTRING);
1323 bout.writeLongUTF(str, utflen);
1324 }
1325 }
1326
1327 /**
1328 * Writes given array object to stream.
1329 */
1330 private void writeArray(Object array,
1331 ObjectStreamClass desc,
1332 boolean unshared)
1333 throws IOException
1334 {
1335 bout.writeByte(TC_ARRAY);
1336 writeClassDesc(desc, false);
1337 handles.assign(unshared ? null : array);
1338
1339 Class<?> ccl = desc.forClass().getComponentType();
1340 if (ccl.isPrimitive()) {
1341 if (ccl == Integer.TYPE) {
1342 int[] ia = (int[]) array;
1343 bout.writeInt(ia.length);
1344 bout.writeInts(ia, 0, ia.length);
1345 } else if (ccl == Byte.TYPE) {
1346 byte[] ba = (byte[]) array;
1347 bout.writeInt(ba.length);
1348 bout.write(ba, 0, ba.length, true);
1349 } else if (ccl == Long.TYPE) {
1350 long[] ja = (long[]) array;
1351 bout.writeInt(ja.length);
1352 bout.writeLongs(ja, 0, ja.length);
1353 } else if (ccl == Float.TYPE) {
1354 float[] fa = (float[]) array;
1355 bout.writeInt(fa.length);
1356 bout.writeFloats(fa, 0, fa.length);
1357 } else if (ccl == Double.TYPE) {
1358 double[] da = (double[]) array;
1359 bout.writeInt(da.length);
1360 bout.writeDoubles(da, 0, da.length);
1361 } else if (ccl == Short.TYPE) {
1362 short[] sa = (short[]) array;
1363 bout.writeInt(sa.length);
1364 bout.writeShorts(sa, 0, sa.length);
1365 } else if (ccl == Character.TYPE) {
1366 char[] ca = (char[]) array;
1367 bout.writeInt(ca.length);
1368 bout.writeChars(ca, 0, ca.length);
1369 } else if (ccl == Boolean.TYPE) {
1370 boolean[] za = (boolean[]) array;
1371 bout.writeInt(za.length);
1372 bout.writeBooleans(za, 0, za.length);
1373 } else {
1374 throw new InternalError();
1375 }
1376 } else {
1377 Object[] objs = (Object[]) array;
1378 int len = objs.length;
1379 bout.writeInt(len);
1380 if (extendedDebugInfo) {
1381 debugInfoStack.push(
1382 "array (class \"" + array.getClass().getName() +
1383 "\", size: " + len + ")");
1384 }
1385 try {
1386 for (int i = 0; i < len; i++) {
1387 if (extendedDebugInfo) {
1388 debugInfoStack.push(
1389 "element of array (index: " + i + ")");
1390 }
1391 try {
1392 writeObject0(objs[i], false);
1393 } finally {
1394 if (extendedDebugInfo) {
1395 debugInfoStack.pop();
1396 }
1397 }
1398 }
1399 } finally {
1400 if (extendedDebugInfo) {
1401 debugInfoStack.pop();
1402 }
1403 }
1404 }
1405 }
1406
1407 /**
1408 * Writes given enum constant to stream.
1409 */
1410 private void writeEnum(Enum<?> en,
1411 ObjectStreamClass desc,
1412 boolean unshared)
1413 throws IOException
1414 {
1415 bout.writeByte(TC_ENUM);
1416 ObjectStreamClass sdesc = desc.getSuperDesc();
1417 writeClassDesc((sdesc.forClass() == Enum.class) ? desc : sdesc, false);
1418 handles.assign(unshared ? null : en);
1419 writeString(en.name(), false);
1420 }
1421
1422 /**
1423 * Writes representation of an "ordinary" (i.e., not a String, Class,
1424 * ObjectStreamClass, array, or enum constant) serializable object to the
1425 * stream.
1426 */
1427 private void writeOrdinaryObject(Object obj,
1428 ObjectStreamClass desc,
1429 boolean unshared)
1430 throws IOException
1431 {
1432 if (extendedDebugInfo) {
1433 debugInfoStack.push(
1434 (depth == 1 ? "root " : "") + "object (class \"" +
1435 obj.getClass().getName() + "\", " + obj.toString() + ")");
1436 }
1437 try {
1438 desc.checkSerialize();
1439
1440 bout.writeByte(TC_OBJECT);
1441 writeClassDesc(desc, false);
1442 handles.assign(unshared ? null : obj);
1443
1444 if (desc.isRecord()) {
1445 writeRecordData(obj, desc);
1446 } else if (desc.isExternalizable() && !desc.isProxy()) {
1447 writeExternalData((Externalizable) obj);
1448 } else {
1449 writeSerialData(obj, desc);
1450 }
1451 } finally {
1452 if (extendedDebugInfo) {
1453 debugInfoStack.pop();
1454 }
1455 }
1456 }
1457
1458 /**
1459 * Writes externalizable data of given object by invoking its
1460 * writeExternal() method.
1461 */
1462 private void writeExternalData(Externalizable obj) throws IOException {
1463 PutFieldImpl oldPut = curPut;
1464 curPut = null;
1465
1466 if (extendedDebugInfo) {
1467 debugInfoStack.push("writeExternal data");
1468 }
1469 SerialCallbackContext oldContext = curContext;
1470 try {
1471 curContext = null;
1472 if (protocol == PROTOCOL_VERSION_1) {
1473 obj.writeExternal(this);
1474 } else {
1475 bout.setBlockDataMode(true);
1476 obj.writeExternal(this);
1477 bout.setBlockDataMode(false);
1478 bout.writeByte(TC_ENDBLOCKDATA);
1479 }
1480 } finally {
1481 curContext = oldContext;
1482 if (extendedDebugInfo) {
1483 debugInfoStack.pop();
1484 }
1485 }
1486
1487 curPut = oldPut;
1488 }
1489
1490 /** Writes the record component values for the given record object. */
1491 private void writeRecordData(Object obj, ObjectStreamClass desc)
1492 throws IOException
1493 {
1494 assert obj.getClass().isRecord();
1495 ObjectStreamClass.ClassDataSlot[] slots = desc.getClassDataLayout();
1496 if (slots.length != 1) {
1497 throw new InvalidClassException(
1498 "expected a single record slot length, but found: " + slots.length);
1499 }
1500
1501 defaultWriteFields(obj, desc); // #### seems unnecessary to use the accessors
1502 }
1503
1504 /**
1505 * Writes instance data for each serializable class of given object, from
1506 * superclass to subclass.
1507 */
1508 private void writeSerialData(Object obj, ObjectStreamClass desc)
1509 throws IOException
1510 {
1511 ObjectStreamClass.ClassDataSlot[] slots = desc.getClassDataLayout();
1512 for (int i = 0; i < slots.length; i++) {
1513 ObjectStreamClass slotDesc = slots[i].desc;
1514 if (slotDesc.hasWriteObjectMethod()) {
1515 PutFieldImpl oldPut = curPut;
1516 curPut = null;
1517 SerialCallbackContext oldContext = curContext;
1518
1519 if (extendedDebugInfo) {
1520 debugInfoStack.push(
1521 "custom writeObject data (class \"" +
1522 slotDesc.getName() + "\")");
1523 }
1524 try {
1525 curContext = new SerialCallbackContext(obj, slotDesc);
1526 bout.setBlockDataMode(true);
1527 slotDesc.invokeWriteObject(obj, this);
1528 bout.setBlockDataMode(false);
1529 bout.writeByte(TC_ENDBLOCKDATA);
1530 } finally {
1531 curContext.setUsed();
1532 curContext = oldContext;
1533 if (extendedDebugInfo) {
1534 debugInfoStack.pop();
1535 }
1536 }
1537
1538 curPut = oldPut;
1539 } else {
1540 defaultWriteFields(obj, slotDesc);
1541 }
1542 }
1543 }
1544
1545 /**
1546 * Fetches and writes values of serializable fields of given object to
1547 * stream. The given class descriptor specifies which field values to
1548 * write, and in which order they should be written.
1549 */
1550 private void defaultWriteFields(Object obj, ObjectStreamClass desc)
1551 throws IOException
1552 {
1553 Class<?> cl = desc.forClass();
1554 if (cl != null && obj != null && !cl.isInstance(obj)) {
1555 throw new ClassCastException();
1556 }
1557
1558 desc.checkDefaultSerialize();
1559
1560 int primDataSize = desc.getPrimDataSize();
1561 if (primDataSize > 0) {
1562 if (primVals == null || primVals.length < primDataSize) {
1563 primVals = new byte[primDataSize];
1564 }
1565 desc.getPrimFieldValues(obj, primVals);
1566 bout.write(primVals, 0, primDataSize, false);
1567 }
1568
1569 int numObjFields = desc.getNumObjFields();
1570 if (numObjFields > 0) {
1571 ObjectStreamField[] fields = desc.getFields(false);
1572 Object[] objVals = new Object[numObjFields];
1573 int numPrimFields = fields.length - objVals.length;
1574 desc.getObjFieldValues(obj, objVals);
1575 for (int i = 0; i < objVals.length; i++) {
1576 if (extendedDebugInfo) {
1577 debugInfoStack.push(
1578 "field (class \"" + desc.getName() + "\", name: \"" +
1579 fields[numPrimFields + i].getName() + "\", type: \"" +
1580 fields[numPrimFields + i].getType() + "\")");
1581 }
1582 try {
1583 writeObject0(objVals[i],
1584 fields[numPrimFields + i].isUnshared());
1585 } finally {
1586 if (extendedDebugInfo) {
1587 debugInfoStack.pop();
1588 }
1589 }
1590 }
1591 }
1592 }
1593
1594 /**
1595 * Attempts to write to stream fatal IOException that has caused
1596 * serialization to abort.
1597 */
1598 private void writeFatalException(IOException ex) throws IOException {
1599 /*
1600 * Note: the serialization specification states that if a second
1601 * IOException occurs while attempting to serialize the original fatal
1602 * exception to the stream, then a StreamCorruptedException should be
1603 * thrown (section 2.1). However, due to a bug in previous
1604 * implementations of serialization, StreamCorruptedExceptions were
1605 * rarely (if ever) actually thrown--the "root" exceptions from
1606 * underlying streams were thrown instead. This historical behavior is
1607 * followed here for consistency.
1608 */
1609 clear();
1610 boolean oldMode = bout.setBlockDataMode(false);
1611 try {
1612 bout.writeByte(TC_EXCEPTION);
1613 writeObject0(ex, false);
1614 clear();
1615 } finally {
1616 bout.setBlockDataMode(oldMode);
1617 }
1618 }
1619
1620 /**
1621 * Default PutField implementation.
1622 */
1623 private class PutFieldImpl extends PutField {
1624
1625 /** class descriptor describing serializable fields */
1626 private final ObjectStreamClass desc;
1627 /** primitive field values */
1628 private final byte[] primVals;
1629 /** object field values */
1630 private final Object[] objVals;
1631
1632 /**
1633 * Creates PutFieldImpl object for writing fields defined in given
1634 * class descriptor.
1635 */
1636 PutFieldImpl(ObjectStreamClass desc) {
1637 this.desc = desc;
1638 primVals = new byte[desc.getPrimDataSize()];
1639 objVals = new Object[desc.getNumObjFields()];
1640 }
1641
1642 public void put(String name, boolean val) {
1643 Bits.putBoolean(primVals, getFieldOffset(name, Boolean.TYPE), val);
1644 }
1645
1646 public void put(String name, byte val) {
1647 primVals[getFieldOffset(name, Byte.TYPE)] = val;
1648 }
1649
1650 public void put(String name, char val) {
1651 Bits.putChar(primVals, getFieldOffset(name, Character.TYPE), val);
1652 }
1653
1654 public void put(String name, short val) {
1655 Bits.putShort(primVals, getFieldOffset(name, Short.TYPE), val);
1656 }
1657
1658 public void put(String name, int val) {
1659 Bits.putInt(primVals, getFieldOffset(name, Integer.TYPE), val);
1660 }
1661
1662 public void put(String name, float val) {
1663 Bits.putFloat(primVals, getFieldOffset(name, Float.TYPE), val);
1664 }
1665
1666 public void put(String name, long val) {
1667 Bits.putLong(primVals, getFieldOffset(name, Long.TYPE), val);
1668 }
1669
1670 public void put(String name, double val) {
1671 Bits.putDouble(primVals, getFieldOffset(name, Double.TYPE), val);
1672 }
1673
1674 public void put(String name, Object val) {
1675 objVals[getFieldOffset(name, Object.class)] = val;
1676 }
1677
1678 // deprecated in ObjectOutputStream.PutField
1679 public void write(ObjectOutput out) throws IOException {
1680 /*
1681 * Applications should *not* use this method to write PutField
1682 * data, as it will lead to stream corruption if the PutField
1683 * object writes any primitive data (since block data mode is not
1684 * unset/set properly, as is done in OOS.writeFields()). This
1685 * broken implementation is being retained solely for behavioral
1686 * compatibility, in order to support applications which use
1687 * OOS.PutField.write() for writing only non-primitive data.
1688 *
1689 * Serialization of unshared objects is not implemented here since
1690 * it is not necessary for backwards compatibility; also, unshared
1691 * semantics may not be supported by the given ObjectOutput
1692 * instance. Applications which write unshared objects using the
1693 * PutField API must use OOS.writeFields().
1694 */
1695 if (ObjectOutputStream.this != out) {
1696 throw new IllegalArgumentException("wrong stream");
1697 }
1698 out.write(primVals, 0, primVals.length);
1699
1700 ObjectStreamField[] fields = desc.getFields(false);
1701 int numPrimFields = fields.length - objVals.length;
1702 // REMIND: warn if numPrimFields > 0?
1703 for (int i = 0; i < objVals.length; i++) {
1704 if (fields[numPrimFields + i].isUnshared()) {
1705 throw new IOException("cannot write unshared object");
1706 }
1707 out.writeObject(objVals[i]);
1708 }
1709 }
1710
1711 /**
1712 * Writes buffered primitive data and object fields to stream.
1713 */
1714 void writeFields() throws IOException {
1715 bout.write(primVals, 0, primVals.length, false);
1716
1717 ObjectStreamField[] fields = desc.getFields(false);
1718 int numPrimFields = fields.length - objVals.length;
1719 for (int i = 0; i < objVals.length; i++) {
1720 if (extendedDebugInfo) {
1721 debugInfoStack.push(
1722 "field (class \"" + desc.getName() + "\", name: \"" +
1723 fields[numPrimFields + i].getName() + "\", type: \"" +
1724 fields[numPrimFields + i].getType() + "\")");
1725 }
1726 try {
1727 writeObject0(objVals[i],
1728 fields[numPrimFields + i].isUnshared());
1729 } finally {
1730 if (extendedDebugInfo) {
1731 debugInfoStack.pop();
1732 }
1733 }
1734 }
1735 }
1736
1737 /**
1738 * Returns offset of field with given name and type. A specified type
1739 * of null matches all types, Object.class matches all non-primitive
1740 * types, and any other non-null type matches assignable types only.
1741 * Throws IllegalArgumentException if no matching field found.
1742 */
1743 private int getFieldOffset(String name, Class<?> type) {
1744 ObjectStreamField field = desc.getField(name, type);
1745 if (field == null) {
1746 throw new IllegalArgumentException("no such field " + name +
1747 " with type " + type);
1748 }
1749 return field.getOffset();
1750 }
1751 }
1752
1753 /**
1754 * Buffered output stream with two modes: in default mode, outputs data in
1755 * same format as DataOutputStream; in "block data" mode, outputs data
1756 * bracketed by block data markers (see object serialization specification
1757 * for details).
1758 */
1759 private static class BlockDataOutputStream
1760 extends OutputStream implements DataOutput
1761 {
1762 /** maximum data block length */
1763 private static final int MAX_BLOCK_SIZE = 1024;
1764 /** maximum data block header length */
1765 private static final int MAX_HEADER_SIZE = 5;
1766 /** (tunable) length of char buffer (for writing strings) */
1767 private static final int CHAR_BUF_SIZE = 256;
1768
1769 /** buffer for writing general/block data */
1770 private final byte[] buf = new byte[MAX_BLOCK_SIZE];
1771 /** buffer for writing block data headers */
1772 private final byte[] hbuf = new byte[MAX_HEADER_SIZE];
1773 /** char buffer for fast string writes */
1774 private final char[] cbuf = new char[CHAR_BUF_SIZE];
1775
1776 /** block data mode */
1777 private boolean blkmode = false;
1778 /** current offset into buf */
1779 private int pos = 0;
1780
1781 /** underlying output stream */
1782 private final OutputStream out;
1783 /** loopback stream (for data writes that span data blocks) */
1784 private final DataOutputStream dout;
1785
1786 /**
1787 * Creates new BlockDataOutputStream on top of given underlying stream.
1788 * Block data mode is turned off by default.
1789 */
1790 BlockDataOutputStream(OutputStream out) {
1791 this.out = out;
1792 dout = new DataOutputStream(this);
1793 }
1794
1795 /**
1796 * Sets block data mode to the given mode (true == on, false == off)
1797 * and returns the previous mode value. If the new mode is the same as
1798 * the old mode, no action is taken. If the new mode differs from the
1799 * old mode, any buffered data is flushed before switching to the new
1800 * mode.
1801 */
1802 boolean setBlockDataMode(boolean mode) throws IOException {
1803 if (blkmode == mode) {
1804 return blkmode;
1805 }
1806 drain();
1807 blkmode = mode;
1808 return !blkmode;
1809 }
1810
1811 /**
1812 * Returns true if the stream is currently in block data mode, false
1813 * otherwise.
1814 */
1815 boolean getBlockDataMode() {
1816 return blkmode;
1817 }
1818
1819 /* ----------------- generic output stream methods ----------------- */
1820 /*
1821 * The following methods are equivalent to their counterparts in
1822 * OutputStream, except that they partition written data into data
1823 * blocks when in block data mode.
1824 */
1825
1826 public void write(int b) throws IOException {
1827 if (pos >= MAX_BLOCK_SIZE) {
1828 drain();
1829 }
1830 buf[pos++] = (byte) b;
1831 }
1832
1833 public void write(byte[] b) throws IOException {
1834 write(b, 0, b.length, false);
1835 }
1836
1837 public void write(byte[] b, int off, int len) throws IOException {
1838 write(b, off, len, false);
1839 }
1840
1841 public void flush() throws IOException {
1842 drain();
1843 out.flush();
1844 }
1845
1846 public void close() throws IOException {
1847 flush();
1848 out.close();
1849 }
1850
1851 /**
1852 * Writes specified span of byte values from given array. If copy is
1853 * true, copies the values to an intermediate buffer before writing
1854 * them to underlying stream (to avoid exposing a reference to the
1855 * original byte array).
1856 */
1857 void write(byte[] b, int off, int len, boolean copy)
1858 throws IOException
1859 {
1860 if (!(copy || blkmode)) { // write directly
1861 drain();
1862 out.write(b, off, len);
1863 return;
1864 }
1865
1866 while (len > 0) {
1867 if (pos >= MAX_BLOCK_SIZE) {
1868 drain();
1869 }
1870 if (len >= MAX_BLOCK_SIZE && !copy && pos == 0) {
1871 // avoid unnecessary copy
1872 writeBlockHeader(MAX_BLOCK_SIZE);
1873 out.write(b, off, MAX_BLOCK_SIZE);
1874 off += MAX_BLOCK_SIZE;
1875 len -= MAX_BLOCK_SIZE;
1876 } else {
1877 int wlen = Math.min(len, MAX_BLOCK_SIZE - pos);
1878 System.arraycopy(b, off, buf, pos, wlen);
1879 pos += wlen;
1880 off += wlen;
1881 len -= wlen;
1882 }
1883 }
1884 }
1885
1886 /**
1887 * Writes all buffered data from this stream to the underlying stream,
1888 * but does not flush underlying stream.
1889 */
1890 void drain() throws IOException {
1891 if (pos == 0) {
1892 return;
1893 }
1894 if (blkmode) {
1895 writeBlockHeader(pos);
1896 }
1897 out.write(buf, 0, pos);
1898 pos = 0;
1899 }
1900
1901 /**
1902 * Writes block data header. Data blocks shorter than 256 bytes are
1903 * prefixed with a 2-byte header; all others start with a 5-byte
1904 * header.
1905 */
1906 private void writeBlockHeader(int len) throws IOException {
1907 if (len <= 0xFF) {
1908 hbuf[0] = TC_BLOCKDATA;
1909 hbuf[1] = (byte) len;
1910 out.write(hbuf, 0, 2);
1911 } else {
1912 hbuf[0] = TC_BLOCKDATALONG;
1913 Bits.putInt(hbuf, 1, len);
1914 out.write(hbuf, 0, 5);
1915 }
1916 }
1917
1918
1919 /* ----------------- primitive data output methods ----------------- */
1920 /*
1921 * The following methods are equivalent to their counterparts in
1922 * DataOutputStream, except that they partition written data into data
1923 * blocks when in block data mode.
1924 */
1925
1926 public void writeBoolean(boolean v) throws IOException {
1927 if (pos >= MAX_BLOCK_SIZE) {
1928 drain();
1929 }
1930 Bits.putBoolean(buf, pos++, v);
1931 }
1932
1933 public void writeByte(int v) throws IOException {
1934 if (pos >= MAX_BLOCK_SIZE) {
1935 drain();
1936 }
1937 buf[pos++] = (byte) v;
1938 }
1939
1940 public void writeChar(int v) throws IOException {
1941 if (pos + 2 <= MAX_BLOCK_SIZE) {
1942 Bits.putChar(buf, pos, (char) v);
1943 pos += 2;
1944 } else {
1945 dout.writeChar(v);
1946 }
1947 }
1948
1949 public void writeShort(int v) throws IOException {
1950 if (pos + 2 <= MAX_BLOCK_SIZE) {
1951 Bits.putShort(buf, pos, (short) v);
1952 pos += 2;
1953 } else {
1954 dout.writeShort(v);
1955 }
1956 }
1957
1958 public void writeInt(int v) throws IOException {
1959 if (pos + 4 <= MAX_BLOCK_SIZE) {
1960 Bits.putInt(buf, pos, v);
1961 pos += 4;
1962 } else {
1963 dout.writeInt(v);
1964 }
1965 }
1966
1967 public void writeFloat(float v) throws IOException {
1968 if (pos + 4 <= MAX_BLOCK_SIZE) {
1969 Bits.putFloat(buf, pos, v);
1970 pos += 4;
1971 } else {
1972 dout.writeFloat(v);
1973 }
1974 }
1975
1976 public void writeLong(long v) throws IOException {
1977 if (pos + 8 <= MAX_BLOCK_SIZE) {
1978 Bits.putLong(buf, pos, v);
1979 pos += 8;
1980 } else {
1981 dout.writeLong(v);
1982 }
1983 }
1984
1985 public void writeDouble(double v) throws IOException {
1986 if (pos + 8 <= MAX_BLOCK_SIZE) {
1987 Bits.putDouble(buf, pos, v);
1988 pos += 8;
1989 } else {
1990 dout.writeDouble(v);
1991 }
1992 }
1993
1994 public void writeBytes(String s) throws IOException {
1995 int endoff = s.length();
1996 int cpos = 0;
1997 int csize = 0;
1998 for (int off = 0; off < endoff; ) {
1999 if (cpos >= csize) {
2000 cpos = 0;
2001 csize = Math.min(endoff - off, CHAR_BUF_SIZE);
2002 s.getChars(off, off + csize, cbuf, 0);
2003 }
2004 if (pos >= MAX_BLOCK_SIZE) {
2005 drain();
2006 }
2007 int n = Math.min(csize - cpos, MAX_BLOCK_SIZE - pos);
2008 int stop = pos + n;
2009 while (pos < stop) {
2010 buf[pos++] = (byte) cbuf[cpos++];
2011 }
2012 off += n;
2013 }
2014 }
2015
2016 public void writeChars(String s) throws IOException {
2017 int endoff = s.length();
2018 for (int off = 0; off < endoff; ) {
2019 int csize = Math.min(endoff - off, CHAR_BUF_SIZE);
2020 s.getChars(off, off + csize, cbuf, 0);
2021 writeChars(cbuf, 0, csize);
2022 off += csize;
2023 }
2024 }
2025
2026 public void writeUTF(String s) throws IOException {
2027 writeUTF(s, getUTFLength(s));
2028 }
2029
2030
2031 /* -------------- primitive data array output methods -------------- */
2032 /*
2033 * The following methods write out spans of primitive data values.
2034 * Though equivalent to calling the corresponding primitive write
2035 * methods repeatedly, these methods are optimized for writing groups
2036 * of primitive data values more efficiently.
2037 */
2038
2039 void writeBooleans(boolean[] v, int off, int len) throws IOException {
2040 int endoff = off + len;
2041 while (off < endoff) {
2042 if (pos >= MAX_BLOCK_SIZE) {
2043 drain();
2044 }
2045 int stop = Math.min(endoff, off + (MAX_BLOCK_SIZE - pos));
2046 while (off < stop) {
2047 Bits.putBoolean(buf, pos++, v[off++]);
2048 }
2049 }
2050 }
2051
2052 void writeChars(char[] v, int off, int len) throws IOException {
2053 int limit = MAX_BLOCK_SIZE - 2;
2054 int endoff = off + len;
2055 while (off < endoff) {
2056 if (pos <= limit) {
2057 int avail = (MAX_BLOCK_SIZE - pos) >> 1;
2058 int stop = Math.min(endoff, off + avail);
2059 while (off < stop) {
2060 Bits.putChar(buf, pos, v[off++]);
2061 pos += 2;
2062 }
2063 } else {
2064 dout.writeChar(v[off++]);
2065 }
2066 }
2067 }
2068
2069 void writeShorts(short[] v, int off, int len) throws IOException {
2070 int limit = MAX_BLOCK_SIZE - 2;
2071 int endoff = off + len;
2072 while (off < endoff) {
2073 if (pos <= limit) {
2074 int avail = (MAX_BLOCK_SIZE - pos) >> 1;
2075 int stop = Math.min(endoff, off + avail);
2076 while (off < stop) {
2077 Bits.putShort(buf, pos, v[off++]);
2078 pos += 2;
2079 }
2080 } else {
2081 dout.writeShort(v[off++]);
2082 }
2083 }
2084 }
2085
2086 void writeInts(int[] v, int off, int len) throws IOException {
2087 int limit = MAX_BLOCK_SIZE - 4;
2088 int endoff = off + len;
2089 while (off < endoff) {
2090 if (pos <= limit) {
2091 int avail = (MAX_BLOCK_SIZE - pos) >> 2;
2092 int stop = Math.min(endoff, off + avail);
2093 while (off < stop) {
2094 Bits.putInt(buf, pos, v[off++]);
2095 pos += 4;
2096 }
2097 } else {
2098 dout.writeInt(v[off++]);
2099 }
2100 }
2101 }
2102
2103 void writeFloats(float[] v, int off, int len) throws IOException {
2104 int limit = MAX_BLOCK_SIZE - 4;
2105 int endoff = off + len;
2106 while (off < endoff) {
2107 if (pos <= limit) {
2108 int avail = (MAX_BLOCK_SIZE - pos) >> 2;
2109 int stop = Math.min(endoff, off + avail);
2110 while (off < stop) {
2111 Bits.putFloat(buf, pos, v[off++]);
2112 pos += 4;
2113 }
2114 } else {
2115 dout.writeFloat(v[off++]);
2116 }
2117 }
2118 }
2119
2120 void writeLongs(long[] v, int off, int len) throws IOException {
2121 int limit = MAX_BLOCK_SIZE - 8;
2122 int endoff = off + len;
2123 while (off < endoff) {
2124 if (pos <= limit) {
2125 int avail = (MAX_BLOCK_SIZE - pos) >> 3;
2126 int stop = Math.min(endoff, off + avail);
2127 while (off < stop) {
2128 Bits.putLong(buf, pos, v[off++]);
2129 pos += 8;
2130 }
2131 } else {
2132 dout.writeLong(v[off++]);
2133 }
2134 }
2135 }
2136
2137 void writeDoubles(double[] v, int off, int len) throws IOException {
2138 int limit = MAX_BLOCK_SIZE - 8;
2139 int endoff = off + len;
2140 while (off < endoff) {
2141 if (pos <= limit) {
2142 int avail = (MAX_BLOCK_SIZE - pos) >> 3;
2143 int stop = Math.min(endoff, off + avail);
2144 while (off < stop) {
2145 Bits.putDouble(buf, pos, v[off++]);
2146 pos += 8;
2147 }
2148 } else {
2149 dout.writeDouble(v[off++]);
2150 }
2151 }
2152 }
2153
2154 /**
2155 * Returns the length in bytes of the UTF encoding of the given string.
2156 */
2157 long getUTFLength(String s) {
2158 int len = s.length();
2159 long utflen = 0;
2160 for (int off = 0; off < len; ) {
2161 int csize = Math.min(len - off, CHAR_BUF_SIZE);
2162 s.getChars(off, off + csize, cbuf, 0);
2163 for (int cpos = 0; cpos < csize; cpos++) {
2164 char c = cbuf[cpos];
2165 if (c >= 0x0001 && c <= 0x007F) {
2166 utflen++;
2167 } else if (c > 0x07FF) {
2168 utflen += 3;
2169 } else {
2170 utflen += 2;
2171 }
2172 }
2173 off += csize;
2174 }
2175 return utflen;
2176 }
2177
2178 /**
2179 * Writes the given string in UTF format. This method is used in
2180 * situations where the UTF encoding length of the string is already
2181 * known; specifying it explicitly avoids a prescan of the string to
2182 * determine its UTF length.
2183 */
2184 void writeUTF(String s, long utflen) throws IOException {
2185 if (utflen > 0xFFFFL) {
2186 throw new UTFDataFormatException();
2187 }
2188 writeShort((int) utflen);
2189 if (utflen == (long) s.length()) {
2190 writeBytes(s);
2191 } else {
2192 writeUTFBody(s);
2193 }
2194 }
2195
2196 /**
2197 * Writes given string in "long" UTF format. "Long" UTF format is
2198 * identical to standard UTF, except that it uses an 8 byte header
2199 * (instead of the standard 2 bytes) to convey the UTF encoding length.
2200 */
2201 void writeLongUTF(String s) throws IOException {
2202 writeLongUTF(s, getUTFLength(s));
2203 }
2204
2205 /**
2206 * Writes given string in "long" UTF format, where the UTF encoding
2207 * length of the string is already known.
2208 */
2209 void writeLongUTF(String s, long utflen) throws IOException {
2210 writeLong(utflen);
2211 if (utflen == (long) s.length()) {
2212 writeBytes(s);
2213 } else {
2214 writeUTFBody(s);
2215 }
2216 }
2217
2218 /**
2219 * Writes the "body" (i.e., the UTF representation minus the 2-byte or
2220 * 8-byte length header) of the UTF encoding for the given string.
2221 */
2222 private void writeUTFBody(String s) throws IOException {
2223 int limit = MAX_BLOCK_SIZE - 3;
2224 int len = s.length();
2225 for (int off = 0; off < len; ) {
2226 int csize = Math.min(len - off, CHAR_BUF_SIZE);
2227 s.getChars(off, off + csize, cbuf, 0);
2228 for (int cpos = 0; cpos < csize; cpos++) {
2229 char c = cbuf[cpos];
2230 if (pos <= limit) {
2231 if (c <= 0x007F && c != 0) {
2232 buf[pos++] = (byte) c;
2233 } else if (c > 0x07FF) {
2234 buf[pos + 2] = (byte) (0x80 | ((c >> 0) & 0x3F));
2235 buf[pos + 1] = (byte) (0x80 | ((c >> 6) & 0x3F));
2236 buf[pos + 0] = (byte) (0xE0 | ((c >> 12) & 0x0F));
2237 pos += 3;
2238 } else {
2239 buf[pos + 1] = (byte) (0x80 | ((c >> 0) & 0x3F));
2240 buf[pos + 0] = (byte) (0xC0 | ((c >> 6) & 0x1F));
2241 pos += 2;
2242 }
2243 } else { // write one byte at a time to normalize block
2244 if (c <= 0x007F && c != 0) {
2245 write(c);
2246 } else if (c > 0x07FF) {
2247 write(0xE0 | ((c >> 12) & 0x0F));
2248 write(0x80 | ((c >> 6) & 0x3F));
2249 write(0x80 | ((c >> 0) & 0x3F));
2250 } else {
2251 write(0xC0 | ((c >> 6) & 0x1F));
2252 write(0x80 | ((c >> 0) & 0x3F));
2253 }
2254 }
2255 }
2256 off += csize;
2257 }
2258 }
2259 }
2260
2261 /**
2262 * Lightweight identity hash table which maps objects to integer handles,
2263 * assigned in ascending order.
2264 */
2265 private static class HandleTable {
2266
2267 /* number of mappings in table/next available handle */
2268 private int size;
2269 /* size threshold determining when to expand hash spine */
2270 private int threshold;
2271 /* factor for computing size threshold */
2272 private final float loadFactor;
2273 /* maps hash value -> candidate handle value */
2274 private int[] spine;
2275 /* maps handle value -> next candidate handle value */
2276 private int[] next;
2277 /* maps handle value -> associated object */
2278 private Object[] objs;
2279
2280 /**
2281 * Creates new HandleTable with given capacity and load factor.
2282 */
2283 HandleTable(int initialCapacity, float loadFactor) {
2284 this.loadFactor = loadFactor;
2285 spine = new int[initialCapacity];
2286 next = new int[initialCapacity];
2287 objs = new Object[initialCapacity];
2288 threshold = (int) (initialCapacity * loadFactor);
2289 clear();
2290 }
2291
2292 /**
2293 * Assigns next available handle to given object, and returns handle
2294 * value. Handles are assigned in ascending order starting at 0.
2295 */
2296 int assign(Object obj) {
2297 if (size >= next.length) {
2298 growEntries();
2299 }
2300 if (size >= threshold) {
2301 growSpine();
2302 }
2303 insert(obj, size);
2304 return size++;
2305 }
2306
2307 /**
2308 * Looks up and returns handle associated with given object, or -1 if
2309 * no mapping found.
2310 */
2311 int lookup(Object obj) {
2312 if (size == 0) {
2313 return -1;
2314 }
2315 int index = hash(obj) % spine.length;
2316 for (int i = spine[index]; i >= 0; i = next[i]) {
2317 if (objs[i] == obj) {
2318 return i;
2319 }
2320 }
2321 return -1;
2322 }
2323
2324 /**
2325 * Resets table to its initial (empty) state.
2326 */
2327 void clear() {
2328 Arrays.fill(spine, -1);
2329 Arrays.fill(objs, 0, size, null);
2330 size = 0;
2331 }
2332
2333 /**
2334 * Returns the number of mappings currently in table.
2335 */
2336 int size() {
2337 return size;
2338 }
2339
2340 /**
2341 * Inserts mapping object -> handle mapping into table. Assumes table
2342 * is large enough to accommodate new mapping.
2343 */
2344 private void insert(Object obj, int handle) {
2345 int index = hash(obj) % spine.length;
2346 objs[handle] = obj;
2347 next[handle] = spine[index];
2348 spine[index] = handle;
2349 }
2350
2351 /**
2352 * Expands the hash "spine" -- equivalent to increasing the number of
2353 * buckets in a conventional hash table.
2354 */
2355 private void growSpine() {
2356 spine = new int[(spine.length << 1) + 1];
2357 threshold = (int) (spine.length * loadFactor);
2358 Arrays.fill(spine, -1);
2359 for (int i = 0; i < size; i++) {
2360 insert(objs[i], i);
2361 }
2362 }
2363
2364 /**
2365 * Increases hash table capacity by lengthening entry arrays.
2366 */
2367 private void growEntries() {
2368 int newLength = (next.length << 1) + 1;
2369 int[] newNext = new int[newLength];
2370 System.arraycopy(next, 0, newNext, 0, size);
2371 next = newNext;
2372
2373 Object[] newObjs = new Object[newLength];
2374 System.arraycopy(objs, 0, newObjs, 0, size);
2375 objs = newObjs;
2376 }
2377
2378 /**
2379 * Returns hash value for given object.
2380 */
2381 private int hash(Object obj) {
2382 return System.identityHashCode(obj) & 0x7FFFFFFF;
2383 }
2384 }
2385
2386 /**
2387 * Lightweight identity hash table which maps objects to replacement
2388 * objects.
2389 */
2390 private static class ReplaceTable {
2391
2392 /* maps object -> index */
2393 private final HandleTable htab;
2394 /* maps index -> replacement object */
2395 private Object[] reps;
2396
2397 /**
2398 * Creates new ReplaceTable with given capacity and load factor.
2399 */
2400 ReplaceTable(int initialCapacity, float loadFactor) {
2401 htab = new HandleTable(initialCapacity, loadFactor);
2402 reps = new Object[initialCapacity];
2403 }
2404
2405 /**
2406 * Enters mapping from object to replacement object.
2407 */
2408 void assign(Object obj, Object rep) {
2409 int index = htab.assign(obj);
2410 while (index >= reps.length) {
2411 grow();
2412 }
2413 reps[index] = rep;
2414 }
2415
2416 /**
2417 * Looks up and returns replacement for given object. If no
2418 * replacement is found, returns the lookup object itself.
2419 */
2420 Object lookup(Object obj) {
2421 int index = htab.lookup(obj);
2422 return (index >= 0) ? reps[index] : obj;
2423 }
2424
2425 /**
2426 * Resets table to its initial (empty) state.
2427 */
2428 void clear() {
2429 Arrays.fill(reps, 0, htab.size(), null);
2430 htab.clear();
2431 }
2432
2433 /**
2434 * Returns the number of mappings currently in table.
2435 */
2436 int size() {
2437 return htab.size();
2438 }
2439
2440 /**
2441 * Increases table capacity.
2442 */
2443 private void grow() {
2444 Object[] newReps = new Object[(reps.length << 1) + 1];
2445 System.arraycopy(reps, 0, newReps, 0, reps.length);
2446 reps = newReps;
2447 }
2448 }
2449
2450 /**
2451 * Stack to keep debug information about the state of the
2452 * serialization process, for embedding in exception messages.
2453 */
2454 private static class DebugTraceInfoStack {
2455 private final List<String> stack;
2456
2457 DebugTraceInfoStack() {
2458 stack = new ArrayList<>();
2459 }
2460
2461 /**
2462 * Removes all of the elements from enclosed list.
2463 */
2464 void clear() {
2465 stack.clear();
2466 }
2467
2468 /**
2469 * Removes the object at the top of enclosed list.
2470 */
2471 void pop() {
2472 stack.remove(stack.size()-1);
2473 }
2474
2475 /**
2476 * Pushes a String onto the top of enclosed list.
2477 */
2478 void push(String entry) {
2479 stack.add("\t- " + entry);
2480 }
2481
2482 /**
2483 * Returns a string representation of this object
2484 */
2485 public String toString() {
2486 StringJoiner sj = new StringJoiner("\n");
2487 for (int i = stack.size() - 1; i >= 0; i--) {
2488 sj.add(stack.get(i));
2489 }
2490 return sj.toString();
2491 }
2492 }
2493
2494 }