gistfile1.txt

           int b, h; ForkJoinTask<?>[] a; Object o;
            if ((b = base) - top >= 0 || (a = array) == null)
                h = b | Integer.MIN_VALUE;  // to sense movement on re-poll
            else {
                long j = (((a.length - 1) & b) << ASHIFT) + ABASE;
                if ((o = U.getObjectVolatile(a, j)) == null)
                    h = 2;                  // retryable
                else if (!(o instanceof CountedCompleter))
                    h = -1;                 // unmatchable
                else {
                    CountedCompleter<?> t = (CountedCompleter<?>)o;
                    for (CountedCompleter<?> r = t;;) {
                        if (r == task) {
                            if (base == b &&
                                U.compareAndSwapObject(a, j, t, null)) {
                                base = b + 1;
                                t.doExec();
                                h = 1;      // success
                            }
                            else
                                h = 2;      // lost CAS
                            break;
                        }
                        else if ((r = r.completer) == null) {
                            h = -1;         // unmatched
                            break;
                        }
                    }
                }
            }
            return h;
            
            
             int s; ForkJoinTask<?>[] a; Object o;
            if (base - (s = top) < 0 && (a = array) != null) {
                long j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE;
                if ((o = U.getObjectVolatile(a, j)) != null &&
                    (o instanceof CountedCompleter)) {
                    CountedCompleter<?> t = (CountedCompleter<?>)o;
                    for (CountedCompleter<?> r = t;;) {
                        if (r == task) {
                            if (mode < 0) { // must lock
                                if (U.compareAndSwapInt(this, QLOCK, 0, 1)) {
                                    if (top == s && array == a &&
                                        U.compareAndSwapObject(a, j, t, null)) {
                                        U.putOrderedInt(this, QTOP, s - 1);
                                        U.putOrderedInt(this, QLOCK, 0);
                                        return t;
                                    }
                                    U.compareAndSwapInt(this, QLOCK, 1, 0);
                                }
                            }
                            else if (U.compareAndSwapObject(a, j, t, null)) {
                                U.putOrderedInt(this, QTOP, s - 1);
                                return t;
                            }
                            break;
                        }
                        else if ((r = r.completer) == null) // try parent
                            break;
                    }
                }
            }
            return null;