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root/jsr166/jsr166/src/jsr166y/ForkJoinTask.java
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Comparing jsr166/src/jsr166y/ForkJoinTask.java (file contents):
Revision 1.44 by jsr166, Wed Aug 19 17:44:45 2009 UTC vs.
Revision 1.48 by dl, Thu May 27 16:46:48 2010 UTC

# Line 139 | Line 139 | import java.util.WeakHashMap;
139   */
140   public abstract class ForkJoinTask<V> implements Future<V>, Serializable {
141  
142 +    /*
143 +     * See the internal documentation of class ForkJoinPool for a
144 +     * general implementation overview.  ForkJoinTasks are mainly
145 +     * responsible for maintaining their "status" field amidst relays
146 +     * to methods in ForkJoinWorkerThread and ForkJoinPool. The
147 +     * methods of this class are more-or-less layered into (1) basic
148 +     * status maintenance (2) execution and awaiting completion (3)
149 +     * user-level methods that additionally report results. This is
150 +     * sometimes hard to see because this file orders exported methods
151 +     * in a way that flows well in javadocs.
152 +     */
153 +
154      /**
155       * Run control status bits packed into a single int to minimize
156       * footprint and to ensure atomicity (via CAS).  Status is
157       * initially zero, and takes on nonnegative values until
158       * completed, upon which status holds COMPLETED. CANCELLED, or
159       * EXCEPTIONAL, which use the top 3 bits.  Tasks undergoing
160 <     * blocking waits by other threads have SIGNAL_MASK bits set --
161 <     * bit 15 for external (nonFJ) waits, and the rest a count of
162 <     * waiting FJ threads.  (This representation relies on
163 <     * ForkJoinPool max thread limits). Completion of a stolen task
164 <     * with SIGNAL_MASK bits set awakens waiter via notifyAll. Even
165 <     * though suboptimal for some purposes, we use basic builtin
166 <     * wait/notify to take advantage of "monitor inflation" in JVMs
167 <     * that we would otherwise need to emulate to avoid adding further
168 <     * per-task bookkeeping overhead. Note that bits 16-28 are
169 <     * currently unused. Also value 0x80000000 is available as spare
170 <     * completion value.
160 >     * blocking waits by other threads have the SIGNAL bit set.
161 >     *
162 >     * Completion of a stolen task with SIGNAL set awakens any waiters
163 >     * via notifyAll. Even though suboptimal for some purposes, we use
164 >     * basic builtin wait/notify to take advantage of "monitor
165 >     * inflation" in JVMs that we would otherwise need to emulate to
166 >     * avoid adding further per-task bookkeeping overhead.  We want
167 >     * these monitors to be "fat", i.e., not use biasing or thin-lock
168 >     * techniques, so use some odd coding idioms that tend to avoid
169 >     * them.
170 >     *
171 >     * Note that bits 1-28 are currently unused. Also value
172 >     * 0x80000000 is available as spare completion value.
173       */
174      volatile int status; // accessed directly by pool and workers
175  
176 <    static final int COMPLETION_MASK      = 0xe0000000;
177 <    static final int NORMAL               = 0xe0000000; // == mask
178 <    static final int CANCELLED            = 0xc0000000;
179 <    static final int EXCEPTIONAL          = 0xa0000000;
180 <    static final int SIGNAL_MASK          = 0x0000ffff;
167 <    static final int INTERNAL_SIGNAL_MASK = 0x00007fff;
168 <    static final int EXTERNAL_SIGNAL      = 0x00008000; // top bit of low word
176 >    private static final int COMPLETION_MASK      = 0xe0000000;
177 >    private static final int NORMAL               = 0xe0000000; // == mask
178 >    private static final int CANCELLED            = 0xc0000000;
179 >    private static final int EXCEPTIONAL          = 0xa0000000;
180 >    private static final int SIGNAL               = 0x00000001;
181  
182      /**
183       * Table of exceptions thrown by tasks, to enable reporting by
# Line 179 | Line 191 | public abstract class ForkJoinTask<V> im
191          Collections.synchronizedMap
192          (new WeakHashMap<ForkJoinTask<?>, Throwable>());
193  
194 <    // within-package utilities
183 <
184 <    /**
185 <     * Gets current worker thread, or null if not a worker thread.
186 <     */
187 <    static ForkJoinWorkerThread getWorker() {
188 <        Thread t = Thread.currentThread();
189 <        return ((t instanceof ForkJoinWorkerThread) ?
190 <                (ForkJoinWorkerThread) t : null);
191 <    }
192 <
193 <    final boolean casStatus(int cmp, int val) {
194 <        return UNSAFE.compareAndSwapInt(this, statusOffset, cmp, val);
195 <    }
196 <
197 <    /**
198 <     * Workaround for not being able to rethrow unchecked exceptions.
199 <     */
200 <    static void rethrowException(Throwable ex) {
201 <        if (ex != null)
202 <            UNSAFE.throwException(ex);
203 <    }
204 <
205 <    // Setting completion status
194 >    // Maintaining completion status
195  
196      /**
197 <     * Marks completion and wakes up threads waiting to join this task.
197 >     * Marks completion and wakes up threads waiting to join this task,
198 >     * also clearing signal request bits.
199       *
200       * @param completion one of NORMAL, CANCELLED, EXCEPTIONAL
201 +     * @return status on exit
202       */
203 <    final void setCompletion(int completion) {
213 <        ForkJoinPool pool = getPool();
214 <        if (pool != null) {
215 <            int s; // Clear signal bits while setting completion status
216 <            do {} while ((s = status) >= 0 && !casStatus(s, completion));
217 <
218 <            if ((s & SIGNAL_MASK) != 0) {
219 <                if ((s &= INTERNAL_SIGNAL_MASK) != 0)
220 <                    pool.updateRunningCount(s);
221 <                synchronized (this) { notifyAll(); }
222 <            }
223 <        }
224 <        else
225 <            externallySetCompletion(completion);
226 <    }
227 <
228 <    /**
229 <     * Version of setCompletion for non-FJ threads.  Leaves signal
230 <     * bits for unblocked threads to adjust, and always notifies.
231 <     */
232 <    private void externallySetCompletion(int completion) {
203 >    private int setCompletion(int completion) {
204          int s;
205 <        do {} while ((s = status) >= 0 &&
206 <                     !casStatus(s, (s & SIGNAL_MASK) | completion));
207 <        synchronized (this) { notifyAll(); }
208 <    }
209 <
239 <    /**
240 <     * Sets status to indicate normal completion.
241 <     */
242 <    final void setNormalCompletion() {
243 <        // Try typical fast case -- single CAS, no signal, not already done.
244 <        // Manually expand casStatus to improve chances of inlining it
245 <        if (!UNSAFE.compareAndSwapInt(this, statusOffset, 0, NORMAL))
246 <            setCompletion(NORMAL);
247 <    }
248 <
249 <    // internal waiting and notification
250 <
251 <    /**
252 <     * Performs the actual monitor wait for awaitDone.
253 <     */
254 <    private void doAwaitDone() {
255 <        // Minimize lock bias and in/de-flation effects by maximizing
256 <        // chances of waiting inside sync
257 <        try {
258 <            while (status >= 0)
259 <                synchronized (this) { if (status >= 0) wait(); }
260 <        } catch (InterruptedException ie) {
261 <            onInterruptedWait();
262 <        }
263 <    }
264 <
265 <    /**
266 <     * Performs the actual timed monitor wait for awaitDone.
267 <     */
268 <    private void doAwaitDone(long startTime, long nanos) {
269 <        synchronized (this) {
270 <            try {
271 <                while (status >= 0) {
272 <                    long nt = nanos - (System.nanoTime() - startTime);
273 <                    if (nt <= 0)
274 <                        break;
275 <                    wait(nt / 1000000, (int) (nt % 1000000));
276 <                }
277 <            } catch (InterruptedException ie) {
278 <                onInterruptedWait();
205 >        while ((s = status) >= 0) {
206 >            if (UNSAFE.compareAndSwapInt(this, statusOffset, s, completion)) {
207 >                if ((s & SIGNAL) != 0)
208 >                    synchronized (this) { notifyAll(); }
209 >                return completion;
210              }
211          }
212 +        return s;
213      }
214  
283    // Awaiting completion
284
215      /**
216 <     * Sets status to indicate there is joiner, then waits for join,
217 <     * surrounded with pool notifications.
288 <     *
289 <     * @return status upon exit
216 >     * Record exception and set exceptional completion
217 >     * @return status on exit
218       */
219 <    private int awaitDone(ForkJoinWorkerThread w,
220 <                          boolean maintainParallelism) {
221 <        ForkJoinPool pool = (w == null) ? null : w.pool;
294 <        int s;
295 <        while ((s = status) >= 0) {
296 <            if (casStatus(s, (pool == null) ? s|EXTERNAL_SIGNAL : s+1)) {
297 <                if (pool == null || !pool.preJoin(this, maintainParallelism))
298 <                    doAwaitDone();
299 <                if (((s = status) & INTERNAL_SIGNAL_MASK) != 0)
300 <                    adjustPoolCountsOnUnblock(pool);
301 <                break;
302 <            }
303 <        }
304 <        return s;
219 >    private int setExceptionalCompletion(Throwable rex) {
220 >        exceptionMap.put(this, rex);
221 >        return setCompletion(EXCEPTIONAL);
222      }
223  
224      /**
225 <     * Timed version of awaitDone
309 <     *
310 <     * @return status upon exit
225 >     * Blocks a worker thread until completion. Called only by pool.
226       */
227 <    private int awaitDone(ForkJoinWorkerThread w, long nanos) {
313 <        ForkJoinPool pool = (w == null) ? null : w.pool;
227 >    final void internalAwaitDone() {
228          int s;
229          while ((s = status) >= 0) {
230 <            if (casStatus(s, (pool == null) ? s|EXTERNAL_SIGNAL : s+1)) {
231 <                long startTime = System.nanoTime();
232 <                if (pool == null || !pool.preJoin(this, false))
233 <                    doAwaitDone(startTime, nanos);
234 <                if ((s = status) >= 0) {
235 <                    adjustPoolCountsOnCancelledWait(pool);
236 <                    s = status;
230 >            synchronized(this) {
231 >                if (UNSAFE.compareAndSwapInt(this, statusOffset, s, s|SIGNAL)){
232 >                    do {
233 >                        try {
234 >                            wait();
235 >                        } catch (InterruptedException ie) {
236 >                            cancelIfTerminating();
237 >                        }
238 >                    } while (status >= 0);
239 >                    break;
240                  }
324                if (s < 0 && (s & INTERNAL_SIGNAL_MASK) != 0)
325                    adjustPoolCountsOnUnblock(pool);
326                break;
241              }
242          }
329        return s;
243      }
244  
245      /**
246 <     * Notifies pool that thread is unblocked. Called by signalled
247 <     * threads when woken by non-FJ threads (which is atypical).
246 >     * Blocks a non-worker-thread until completion.
247 >     * @return status on exit
248       */
249 <    private void adjustPoolCountsOnUnblock(ForkJoinPool pool) {
249 >    private int externalAwaitDone() {
250          int s;
251 <        do {} while ((s = status) < 0 && !casStatus(s, s & COMPLETION_MASK));
252 <        if (pool != null && (s &= INTERNAL_SIGNAL_MASK) != 0)
253 <            pool.updateRunningCount(s);
254 <    }
255 <
256 <    /**
257 <     * Notifies pool to adjust counts on cancelled or timed out wait.
258 <     */
259 <    private void adjustPoolCountsOnCancelledWait(ForkJoinPool pool) {
260 <        if (pool != null) {
261 <            int s;
262 <            while ((s = status) >= 0 && (s & INTERNAL_SIGNAL_MASK) != 0) {
263 <                if (casStatus(s, s - 1)) {
351 <                    pool.updateRunningCount(1);
251 >        while ((s = status) >= 0) {
252 >            synchronized(this) {
253 >                if (UNSAFE.compareAndSwapInt(this, statusOffset, s, s|SIGNAL)){
254 >                    boolean interrupted = false;
255 >                    do {
256 >                        try {
257 >                            wait();
258 >                        } catch (InterruptedException ie) {
259 >                            interrupted = true;
260 >                        }
261 >                    } while ((s = status) >= 0);
262 >                    if (interrupted)
263 >                        Thread.currentThread().interrupt();
264                      break;
265                  }
266              }
267          }
268 +        return s;
269      }
270  
271      /**
272 <     * Handles interruptions during waits.
273 <     */
361 <    private void onInterruptedWait() {
362 <        ForkJoinWorkerThread w = getWorker();
363 <        if (w == null)
364 <            Thread.currentThread().interrupt(); // re-interrupt
365 <        else if (w.isTerminating())
366 <            cancelIgnoringExceptions();
367 <        // else if FJworker, ignore interrupt
368 <    }
369 <
370 <    // Recording and reporting exceptions
371 <
372 <    private void setDoneExceptionally(Throwable rex) {
373 <        exceptionMap.put(this, rex);
374 <        setCompletion(EXCEPTIONAL);
375 <    }
376 <
377 <    /**
378 <     * Throws the exception associated with status s.
379 <     *
380 <     * @throws the exception
272 >     * Unless done, calls exec and records status if completed, but
273 >     * doesn't wait for completion otherwise.
274       */
275 <    private void reportException(int s) {
276 <        if ((s &= COMPLETION_MASK) < NORMAL) {
277 <            if (s == CANCELLED)
278 <                throw new CancellationException();
279 <            else
280 <                rethrowException(exceptionMap.get(this));
275 >    final void tryExec() {
276 >        try {
277 >            if (status < 0 || !exec())
278 >                return;
279 >        } catch (Throwable rex) {
280 >            setExceptionalCompletion(rex);
281 >            return;
282          }
283 +        setCompletion(NORMAL); // must be outside try block
284      }
285  
286      /**
287 <     * Returns result or throws exception using j.u.c.Future conventions.
288 <     * Only call when {@code isDone} known to be true or thread known
289 <     * to be interrupted.
287 >     * If not done and this task is next in worker queue, runs it,
288 >     * else waits for it.
289 >     * @return status on exit
290       */
291 <    private V reportFutureResult()
292 <        throws InterruptedException, ExecutionException {
293 <        if (Thread.interrupted())
294 <            throw new InterruptedException();
295 <        int s = status & COMPLETION_MASK;
296 <        if (s < NORMAL) {
297 <            Throwable ex;
298 <            if (s == CANCELLED)
299 <                throw new CancellationException();
300 <            if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null)
301 <                throw new ExecutionException(ex);
291 >    private int waitingJoin() {
292 >        int s = status;
293 >        if (s < 0)
294 >            return s;
295 >        Thread t = Thread.currentThread();
296 >        if (t instanceof ForkJoinWorkerThread) {
297 >            ForkJoinWorkerThread w = (ForkJoinWorkerThread) t;
298 >            if (w.unpushTask(this)) {
299 >                boolean completed;
300 >                try {
301 >                    completed = exec();
302 >                } catch (Throwable rex) {
303 >                    return setExceptionalCompletion(rex);
304 >                }
305 >                if (completed)
306 >                    return setCompletion(NORMAL);
307 >            }
308 >            return w.pool.awaitJoin(this);
309          }
408        return getRawResult();
409    }
410
411    /**
412     * Returns result or throws exception using j.u.c.Future conventions
413     * with timeouts.
414     */
415    private V reportTimedFutureResult()
416        throws InterruptedException, ExecutionException, TimeoutException {
417        if (Thread.interrupted())
418            throw new InterruptedException();
419        Throwable ex;
420        int s = status & COMPLETION_MASK;
421        if (s == NORMAL)
422            return getRawResult();
423        else if (s == CANCELLED)
424            throw new CancellationException();
425        else if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null)
426            throw new ExecutionException(ex);
310          else
311 <            throw new TimeoutException();
311 >            return externalAwaitDone();
312      }
313  
431    // internal execution methods
432
314      /**
315 <     * Calls exec, recording completion, and rethrowing exception if
316 <     * encountered. Caller should normally check status before calling.
317 <     *
437 <     * @return true if completed normally
315 >     * Unless done, calls exec and records status if completed, or
316 >     * waits for completion otherwise.
317 >     * @return status on exit
318       */
319 <    private boolean tryExec() {
320 <        try { // try block must contain only call to exec
321 <            if (!exec())
322 <                return false;
319 >    private int waitingInvoke() {
320 >        int s = status;
321 >        if (s < 0)
322 >            return s;
323 >        boolean completed;
324 >        try {
325 >            completed = exec();
326          } catch (Throwable rex) {
327 <            setDoneExceptionally(rex);
445 <            rethrowException(rex);
446 <            return false; // not reached
327 >            return setExceptionalCompletion(rex);
328          }
329 <        setNormalCompletion();
330 <        return true;
329 >        if (completed)
330 >            return setCompletion(NORMAL);
331 >        return waitingJoin();
332      }
333  
334      /**
335 <     * Main execution method used by worker threads. Invokes
336 <     * base computation unless already complete.
335 >     * If this task is next in worker queue, runs it, else processes other
336 >     * tasks until complete.
337 >     * @return status on exit
338       */
339 <    final void quietlyExec() {
340 <        if (status >= 0) {
339 >    private int busyJoin() {
340 >        int s = status;
341 >        if (s < 0)
342 >            return s;
343 >        ForkJoinWorkerThread w = (ForkJoinWorkerThread) Thread.currentThread();
344 >        if (w.unpushTask(this)) {
345 >            boolean completed;
346              try {
347 <                if (!exec())
460 <                    return;
347 >                completed = exec();
348              } catch (Throwable rex) {
349 <                setDoneExceptionally(rex);
463 <                return;
349 >                return setExceptionalCompletion(rex);
350              }
351 <            setNormalCompletion();
352 <        }
467 <    }
468 <
469 <    /**
470 <     * Calls exec(), recording but not rethrowing exception.
471 <     * Caller should normally check status before calling.
472 <     *
473 <     * @return true if completed normally
474 <     */
475 <    private boolean tryQuietlyInvoke() {
476 <        try {
477 <            if (!exec())
478 <                return false;
479 <        } catch (Throwable rex) {
480 <            setDoneExceptionally(rex);
481 <            return false;
482 <        }
483 <        setNormalCompletion();
484 <        return true;
485 <    }
486 <
487 <    /**
488 <     * Cancels, ignoring any exceptions it throws.
489 <     */
490 <    final void cancelIgnoringExceptions() {
491 <        try {
492 <            cancel(false);
493 <        } catch (Throwable ignore) {
351 >            if (completed)
352 >                return setCompletion(NORMAL);
353          }
354 +        return w.execWhileJoining(this);
355      }
356  
357      /**
358 <     * Main implementation of helpJoin
358 >     * Returns result or throws exception associated with given status.
359 >     * @param s the status
360       */
361 <    private int busyJoin(ForkJoinWorkerThread w) {
362 <        int s;
363 <        ForkJoinTask<?> t;
364 <        while ((s = status) >= 0 && (t = w.scanWhileJoining(this)) != null)
365 <            t.quietlyExec();
505 <        return (s >= 0) ? awaitDone(w, false) : s; // block if no work
361 >    private V reportResult(int s) {
362 >        Throwable ex;
363 >        if (s < NORMAL && (ex = getException()) != null)
364 >            UNSAFE.throwException(ex);
365 >        return getRawResult();
366      }
367  
368      // public methods
# Line 540 | Line 400 | public abstract class ForkJoinTask<V> im
400       * @return the computed result
401       */
402      public final V join() {
403 <        ForkJoinWorkerThread w = getWorker();
544 <        if (w == null || status < 0 || !w.unpushTask(this) || !tryExec())
545 <            reportException(awaitDone(w, true));
546 <        return getRawResult();
403 >        return reportResult(waitingJoin());
404      }
405  
406      /**
# Line 554 | Line 411 | public abstract class ForkJoinTask<V> im
411       * @return the computed result
412       */
413      public final V invoke() {
414 <        if (status >= 0 && tryExec())
558 <            return getRawResult();
559 <        else
560 <            return join();
414 >        return reportResult(waitingInvoke());
415      }
416  
417      /**
# Line 615 | Line 469 | public abstract class ForkJoinTask<V> im
469              }
470              else if (i != 0)
471                  t.fork();
472 <            else {
473 <                t.quietlyInvoke();
620 <                if (ex == null)
621 <                    ex = t.getException();
622 <            }
472 >            else if (t.waitingInvoke() < NORMAL && ex == null)
473 >                ex = t.getException();
474          }
475          for (int i = 1; i <= last; ++i) {
476              ForkJoinTask<?> t = tasks[i];
477              if (t != null) {
478                  if (ex != null)
479                      t.cancel(false);
480 <                else {
481 <                    t.quietlyJoin();
631 <                    if (ex == null)
632 <                        ex = t.getException();
633 <                }
480 >                else if (t.waitingJoin() < NORMAL && ex == null)
481 >                    ex = t.getException();
482              }
483          }
484          if (ex != null)
485 <            rethrowException(ex);
485 >            UNSAFE.throwException(ex);
486      }
487  
488      /**
# Line 677 | Line 525 | public abstract class ForkJoinTask<V> im
525              }
526              else if (i != 0)
527                  t.fork();
528 <            else {
529 <                t.quietlyInvoke();
682 <                if (ex == null)
683 <                    ex = t.getException();
684 <            }
528 >            else if (t.waitingInvoke() < NORMAL && ex == null)
529 >                ex = t.getException();
530          }
531          for (int i = 1; i <= last; ++i) {
532              ForkJoinTask<?> t = ts.get(i);
533              if (t != null) {
534                  if (ex != null)
535                      t.cancel(false);
536 <                else {
537 <                    t.quietlyJoin();
693 <                    if (ex == null)
694 <                        ex = t.getException();
695 <                }
536 >                else if (t.waitingJoin() < NORMAL && ex == null)
537 >                    ex = t.getException();
538              }
539          }
540          if (ex != null)
541 <            rethrowException(ex);
541 >            UNSAFE.throwException(ex);
542          return tasks;
543      }
544  
# Line 729 | Line 571 | public abstract class ForkJoinTask<V> im
571          return (status & COMPLETION_MASK) == CANCELLED;
572      }
573  
574 +    /**
575 +     * Cancels, ignoring any exceptions it throws. Used during worker
576 +     * and pool shutdown.
577 +     */
578 +    final void cancelIgnoringExceptions() {
579 +        try {
580 +            cancel(false);
581 +        } catch (Throwable ignore) {
582 +        }
583 +    }
584 +
585 +    /**
586 +     * Cancels ignoring exceptions if worker is terminating
587 +     */
588 +    private void cancelIfTerminating() {
589 +        Thread t = Thread.currentThread();
590 +        if ((t instanceof ForkJoinWorkerThread) &&
591 +            ((ForkJoinWorkerThread) t).isTerminating()) {
592 +            try {
593 +                cancel(false);
594 +            } catch (Throwable ignore) {
595 +            }
596 +        }
597 +    }
598 +
599      public final boolean isDone() {
600          return status < 0;
601      }
# Line 786 | Line 653 | public abstract class ForkJoinTask<V> im
653       * thrown will be a {@code RuntimeException} with cause {@code ex}.
654       */
655      public void completeExceptionally(Throwable ex) {
656 <        setDoneExceptionally((ex instanceof RuntimeException) ||
657 <                             (ex instanceof Error) ? ex :
658 <                             new RuntimeException(ex));
656 >        setExceptionalCompletion((ex instanceof RuntimeException) ||
657 >                                 (ex instanceof Error) ? ex :
658 >                                 new RuntimeException(ex));
659      }
660  
661      /**
# Line 807 | Line 674 | public abstract class ForkJoinTask<V> im
674          try {
675              setRawResult(value);
676          } catch (Throwable rex) {
677 <            setDoneExceptionally(rex);
677 >            setExceptionalCompletion(rex);
678              return;
679          }
680 <        setNormalCompletion();
680 >        setCompletion(NORMAL);
681      }
682  
683      public final V get() throws InterruptedException, ExecutionException {
684 <        ForkJoinWorkerThread w = getWorker();
685 <        if (w == null || status < 0 || !w.unpushTask(this) || !tryQuietlyInvoke())
686 <            awaitDone(w, true);
687 <        return reportFutureResult();
684 >        int s = waitingJoin() & COMPLETION_MASK;
685 >        if (Thread.interrupted())
686 >            throw new InterruptedException();
687 >        if (s < NORMAL) {
688 >            Throwable ex;
689 >            if (s == CANCELLED)
690 >                throw new CancellationException();
691 >            if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null)
692 >                throw new ExecutionException(ex);
693 >        }
694 >        return getRawResult();
695      }
696  
697      public final V get(long timeout, TimeUnit unit)
698          throws InterruptedException, ExecutionException, TimeoutException {
699 <        long nanos = unit.toNanos(timeout);
700 <        ForkJoinWorkerThread w = getWorker();
701 <        if (w == null || status < 0 || !w.unpushTask(this) || !tryQuietlyInvoke())
702 <            awaitDone(w, nanos);
703 <        return reportTimedFutureResult();
699 >        Thread t = Thread.currentThread();
700 >        ForkJoinPool pool;
701 >        if (t instanceof ForkJoinWorkerThread) {
702 >            ForkJoinWorkerThread w = (ForkJoinWorkerThread) t;
703 >            if (status >= 0 && w.unpushTask(this))
704 >                tryExec();
705 >            pool = w.pool;
706 >        }
707 >        else
708 >            pool = null;
709 >        /*
710 >         * Timed wait loop intermixes cases for fj (pool != null) and
711 >         * non FJ threads. For FJ, decrement pool count but don't try
712 >         * for replacement; increment count on completion. For non-FJ,
713 >         * deal with interrupts. This is messy, but a little less so
714 >         * than is splitting the FJ and nonFJ cases.
715 >         */
716 >        boolean interrupted = false;
717 >        boolean dec = false; // true if pool count decremented
718 >        for (;;) {
719 >            if (Thread.interrupted() && pool == null) {
720 >                interrupted = true;
721 >                break;
722 >            }
723 >            int s = status;
724 >            if (s < 0)
725 >                break;
726 >            if (UNSAFE.compareAndSwapInt(this, statusOffset,
727 >                                         s, s | SIGNAL)) {
728 >                long startTime = System.nanoTime();
729 >                long nanos = unit.toNanos(timeout);
730 >                long nt; // wait time
731 >                while (status >= 0 &&
732 >                       (nt = nanos - (System.nanoTime() - startTime)) > 0) {
733 >                    if (pool != null && !dec)
734 >                        dec = pool.tryDecrementRunningCount();
735 >                    else {
736 >                        long ms = nt / 1000000;
737 >                        int ns = (int) (nt % 1000000);
738 >                        try {
739 >                            synchronized(this) {
740 >                                if (status >= 0)
741 >                                    wait(ms, ns);
742 >                            }
743 >                        } catch (InterruptedException ie) {
744 >                            if (pool != null)
745 >                                cancelIfTerminating();
746 >                            else {
747 >                                interrupted = true;
748 >                                break;
749 >                            }
750 >                        }
751 >                    }
752 >                }
753 >                break;
754 >            }
755 >        }
756 >        if (pool != null && dec)
757 >            pool.updateRunningCount(1);
758 >        if (interrupted)
759 >            throw new InterruptedException();
760 >        int es = status & COMPLETION_MASK;
761 >        if (es != NORMAL) {
762 >            Throwable ex;
763 >            if (es == CANCELLED)
764 >                throw new CancellationException();
765 >            if (es == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null)
766 >                throw new ExecutionException(ex);
767 >            throw new TimeoutException();
768 >        }
769 >        return getRawResult();
770      }
771  
772      /**
# Line 847 | Line 787 | public abstract class ForkJoinTask<V> im
787       * @return the computed result
788       */
789      public final V helpJoin() {
790 <        ForkJoinWorkerThread w = (ForkJoinWorkerThread) Thread.currentThread();
851 <        if (status < 0 || !w.unpushTask(this) || !tryExec())
852 <            reportException(busyJoin(w));
853 <        return getRawResult();
790 >        return reportResult(busyJoin());
791      }
792  
793      /**
# Line 866 | Line 803 | public abstract class ForkJoinTask<V> im
803       * ClassCastException}.
804       */
805      public final void quietlyHelpJoin() {
806 <        if (status >= 0) {
870 <            ForkJoinWorkerThread w =
871 <                (ForkJoinWorkerThread) Thread.currentThread();
872 <            if (!w.unpushTask(this) || !tryQuietlyInvoke())
873 <                busyJoin(w);
874 <        }
806 >        busyJoin();
807      }
808  
809      /**
# Line 881 | Line 813 | public abstract class ForkJoinTask<V> im
813       * known to have aborted.
814       */
815      public final void quietlyJoin() {
816 <        if (status >= 0) {
885 <            ForkJoinWorkerThread w = getWorker();
886 <            if (w == null || !w.unpushTask(this) || !tryQuietlyInvoke())
887 <                awaitDone(w, true);
888 <        }
816 >        waitingJoin();
817      }
818  
819      /**
# Line 896 | Line 824 | public abstract class ForkJoinTask<V> im
824       * known to have aborted.
825       */
826      public final void quietlyInvoke() {
827 <        if (status >= 0 && !tryQuietlyInvoke())
900 <            quietlyJoin();
827 >        waitingInvoke();
828      }
829  
830      /**
# Line 1219 | Line 1146 | public abstract class ForkJoinTask<V> im
1146      private static final long serialVersionUID = -7721805057305804111L;
1147  
1148      /**
1149 <     * Save the state to a stream.
1149 >     * Saves the state to a stream.
1150       *
1151       * @serialData the current run status and the exception thrown
1152       * during execution, or {@code null} if none
# Line 1232 | Line 1159 | public abstract class ForkJoinTask<V> im
1159      }
1160  
1161      /**
1162 <     * Reconstitute the instance from a stream.
1162 >     * Reconstitutes the instance from a stream.
1163       *
1164       * @param s the stream
1165       */
1166      private void readObject(java.io.ObjectInputStream s)
1167          throws java.io.IOException, ClassNotFoundException {
1168          s.defaultReadObject();
1169 <        status &= ~INTERNAL_SIGNAL_MASK; // clear internal signal counts
1243 <        status |= EXTERNAL_SIGNAL; // conservatively set external signal
1169 >        status |= SIGNAL; // conservatively set external signal
1170          Object ex = s.readObject();
1171          if (ex != null)
1172 <            setDoneExceptionally((Throwable) ex);
1172 >            setExceptionalCompletion((Throwable) ex);
1173      }
1174  
1175      // Unsafe mechanics

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