| 479 |
|
} |
| 480 |
|
|
| 481 |
|
/* |
| 482 |
< |
* Possible values for "how" argument in xfer method. Beware that |
| 483 |
< |
* the order of assigned numerical values matters. |
| 482 |
> |
* Possible values for "how" argument in xfer method. |
| 483 |
|
*/ |
| 484 |
|
private static final int NOW = 0; // for untimed poll, tryTransfer |
| 485 |
|
private static final int ASYNC = 1; // for offer, put, add |
| 536 |
|
p = (p != n) ? n : (h = head); // Use head if p offlist |
| 537 |
|
} |
| 538 |
|
|
| 539 |
< |
if (how >= ASYNC) { // No matches available |
| 539 |
> |
if (how != NOW) { // No matches available |
| 540 |
|
if (s == null) |
| 541 |
|
s = new Node(e, haveData); |
| 542 |
|
Node pred = tryAppend(s, haveData); |
| 543 |
|
if (pred == null) |
| 544 |
|
continue retry; // lost race vs opposite mode |
| 545 |
< |
if (how >= SYNC) |
| 546 |
< |
return awaitMatch(s, pred, e, how, nanos); |
| 545 |
> |
if (how != ASYNC) |
| 546 |
> |
return awaitMatch(s, pred, e, (how == TIMEOUT), nanos); |
| 547 |
|
} |
| 548 |
|
return e; // not waiting |
| 549 |
|
} |
| 592 |
|
* predecessor, or null if unknown (the null case does not occur |
| 593 |
|
* in any current calls but may in possible future extensions) |
| 594 |
|
* @param e the comparison value for checking match |
| 595 |
< |
* @param how either SYNC or TIMEOUT |
| 595 |
> |
* @param timed if true, wait only until timeout elapses |
| 596 |
|
* @param nanos timeout value |
| 597 |
|
* @return matched item, or e if unmatched on interrupt or timeout |
| 598 |
|
*/ |
| 599 |
< |
private E awaitMatch(Node s, Node pred, E e, int how, long nanos) { |
| 600 |
< |
long lastTime = (how == TIMEOUT) ? System.nanoTime() : 0L; |
| 599 |
> |
private E awaitMatch(Node s, Node pred, E e, boolean timed, long nanos) { |
| 600 |
> |
long lastTime = timed ? System.nanoTime() : 0L; |
| 601 |
|
Thread w = Thread.currentThread(); |
| 602 |
|
int spins = -1; // initialized after first item and cancel checks |
| 603 |
|
ThreadLocalRandom randomYields = null; // bound if needed |
| 609 |
|
s.forgetContents(); // avoid garbage |
| 610 |
|
return this.<E>cast(item); |
| 611 |
|
} |
| 612 |
< |
if ((w.isInterrupted() || (how == TIMEOUT && nanos <= 0)) && |
| 612 |
> |
if ((w.isInterrupted() || (timed && nanos <= 0)) && |
| 613 |
|
s.casItem(e, s)) { // cancel |
| 614 |
|
unsplice(pred, s); |
| 615 |
|
return e; |
| 628 |
|
else if (s.waiter == null) { |
| 629 |
|
s.waiter = w; // request unpark then recheck |
| 630 |
|
} |
| 631 |
< |
else if (how == TIMEOUT) { |
| 631 |
> |
else if (timed) { |
| 632 |
|
long now = System.nanoTime(); |
| 633 |
|
if ((nanos -= now - lastTime) > 0) |
| 634 |
|
LockSupport.parkNanos(this, nanos); |
| 682 |
|
/* -------------- Traversal methods -------------- */ |
| 683 |
|
|
| 684 |
|
/** |
| 685 |
+ |
* Returns the successor of p, or the head node if p.next has been |
| 686 |
+ |
* linked to self, which will only be true if traversing with a |
| 687 |
+ |
* stale pointer that is now off the list. |
| 688 |
+ |
*/ |
| 689 |
+ |
final Node succ(Node p) { |
| 690 |
+ |
Node next = p.next; |
| 691 |
+ |
return (p == next) ? head : next; |
| 692 |
+ |
} |
| 693 |
+ |
|
| 694 |
+ |
/** |
| 695 |
|
* Returns the first unmatched node of the given mode, or null if |
| 696 |
|
* none. Used by methods isEmpty, hasWaitingConsumer. |
| 697 |
|
*/ |
| 698 |
< |
private Node firstOfMode(boolean data) { |
| 699 |
< |
for (Node p = head; p != null; ) { |
| 698 |
> |
private Node firstOfMode(boolean isData) { |
| 699 |
> |
for (Node p = head; p != null; p = succ(p)) { |
| 700 |
|
if (!p.isMatched()) |
| 701 |
< |
return (p.isData == data) ? p : null; |
| 693 |
< |
Node n = p.next; |
| 694 |
< |
p = (n != p) ? n : head; |
| 701 |
> |
return (p.isData == isData) ? p : null; |
| 702 |
|
} |
| 703 |
|
return null; |
| 704 |
|
} |
| 708 |
|
* null if none. Used by peek. |
| 709 |
|
*/ |
| 710 |
|
private E firstDataItem() { |
| 711 |
< |
for (Node p = head; p != null; ) { |
| 705 |
< |
boolean isData = p.isData; |
| 711 |
> |
for (Node p = head; p != null; p = succ(p)) { |
| 712 |
|
Object item = p.item; |
| 713 |
< |
if (item != p && (item != null) == isData) |
| 714 |
< |
return isData ? this.<E>cast(item) : null; |
| 715 |
< |
Node n = p.next; |
| 716 |
< |
p = (n != p) ? n : head; |
| 713 |
> |
if (p.isData) { |
| 714 |
> |
if (item != null && item != p) |
| 715 |
> |
return this.<E>cast(item); |
| 716 |
> |
} |
| 717 |
> |
else if (item == null) |
| 718 |
> |
return null; |
| 719 |
|
} |
| 720 |
|
return null; |
| 721 |
|
} |
| 756 |
|
private void advance(Node prev) { |
| 757 |
|
lastPred = lastRet; |
| 758 |
|
lastRet = prev; |
| 759 |
< |
Node p; |
| 760 |
< |
if (prev == null || (p = prev.next) == prev) |
| 753 |
< |
p = head; |
| 754 |
< |
while (p != null) { |
| 759 |
> |
for (Node p = (prev == null) ? head : succ(prev); |
| 760 |
> |
p != null; p = succ(p)) { |
| 761 |
|
Object item = p.item; |
| 762 |
|
if (p.isData) { |
| 763 |
|
if (item != null && item != p) { |
| 768 |
|
} |
| 769 |
|
else if (item == null) |
| 770 |
|
break; |
| 765 |
– |
Node n = p.next; |
| 766 |
– |
p = (n != p) ? n : head; |
| 771 |
|
} |
| 772 |
|
nextNode = null; |
| 773 |
|
} |
