The Tor Browser: nsprpub/pr/src/io/prmwait.c@6474c204b198 (annotated)

nsprpub/pr/src/io/prmwait.c@6474c204b198 (annotated)

nsprpub/pr/src/io/prmwait.c

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "primpl.h"
 #include "pprmwait.h"
 #define _MW_REHASH_MAX 11
 static PRLock *mw_lock = NULL;
 static _PRGlobalState *mw_state = NULL;
 static PRIntervalTime max_polling_interval;
 #ifdef WINNT
 typedef struct TimerEvent {
     PRIntervalTime absolute;
     void (*func)(void *);
     void *arg;
     LONG ref_count;
     PRCList links;
 } TimerEvent;
 #define TIMER_EVENT_PTR(_qp) \
     ((TimerEvent *) ((char *) (_qp) - offsetof(TimerEvent, links)))
 struct {
     PRLock *ml;
     PRCondVar *new_timer;
     PRCondVar *cancel_timer;
     PRThread *manager_thread;
     PRCList timer_queue;
 } tm_vars;
 static PRStatus TimerInit(void);
 static void TimerManager(void *arg);
 static TimerEvent *CreateTimer(PRIntervalTime timeout,
     void (*func)(void *), void *arg);
 static PRBool CancelTimer(TimerEvent *timer);
 static void TimerManager(void *arg)
 {
     PRIntervalTime now;
     PRIntervalTime timeout;
     PRCList *head;
     TimerEvent *timer;
     PR_Lock(tm_vars.ml);
     while (1)
     {
         if (PR_CLIST_IS_EMPTY(&tm_vars.timer_queue))
         {
             PR_WaitCondVar(tm_vars.new_timer, PR_INTERVAL_NO_TIMEOUT);
         }
         else
         {
             now = PR_IntervalNow();
             head = PR_LIST_HEAD(&tm_vars.timer_queue);
             timer = TIMER_EVENT_PTR(head);
             if ((PRInt32) (now - timer->absolute) >= 0)
             {
                 PR_REMOVE_LINK(head);
                 /*
                  * make its prev and next point to itself so that
                  * it's obvious that it's not on the timer_queue.
                  */
                 PR_INIT_CLIST(head);
                 PR_ASSERT(2 == timer->ref_count);
                 PR_Unlock(tm_vars.ml);
                 timer->func(timer->arg);
                 PR_Lock(tm_vars.ml);
                 timer->ref_count -= 1;
                 if (0 == timer->ref_count)
                 {
                     PR_NotifyAllCondVar(tm_vars.cancel_timer);
                 }
             }
             else
             {
                 timeout = (PRIntervalTime)(timer->absolute - now);
                 PR_WaitCondVar(tm_vars.new_timer, timeout);
             }
         }
     }
     PR_Unlock(tm_vars.ml);
 }
 static TimerEvent *CreateTimer(
     PRIntervalTime timeout,
     void (*func)(void *),
     void *arg)
 {
     TimerEvent *timer;
     PRCList *links, *tail;
     TimerEvent *elem;
     timer = PR_NEW(TimerEvent);
     if (NULL == timer)
     {
         PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
         return timer;
     }
     timer->absolute = PR_IntervalNow() + timeout;
     timer->func = func;
     timer->arg = arg;
     timer->ref_count = 2;
     PR_Lock(tm_vars.ml);
     tail = links = PR_LIST_TAIL(&tm_vars.timer_queue);
     while (links->prev != tail)
     {
         elem = TIMER_EVENT_PTR(links);
         if ((PRInt32)(timer->absolute - elem->absolute) >= 0)
         {
             break;
         }
         links = links->prev;
     }
     PR_INSERT_AFTER(&timer->links, links);
     PR_NotifyCondVar(tm_vars.new_timer);
     PR_Unlock(tm_vars.ml);
     return timer;
 }
 static PRBool CancelTimer(TimerEvent *timer)
 {
     PRBool canceled = PR_FALSE;
     PR_Lock(tm_vars.ml);
     timer->ref_count -= 1;
     if (timer->links.prev == &timer->links)
     {
         while (timer->ref_count == 1)
         {
             PR_WaitCondVar(tm_vars.cancel_timer, PR_INTERVAL_NO_TIMEOUT);
         }
     }
     else
     {
         PR_REMOVE_LINK(&timer->links);
         canceled = PR_TRUE;
     }
     PR_Unlock(tm_vars.ml);
     PR_DELETE(timer);
     return canceled;
 }
 static PRStatus TimerInit(void)
 {
     tm_vars.ml = PR_NewLock();
     if (NULL == tm_vars.ml)
     {
         goto failed;
     }
     tm_vars.new_timer = PR_NewCondVar(tm_vars.ml);
     if (NULL == tm_vars.new_timer)
     {
         goto failed;
     }
     tm_vars.cancel_timer = PR_NewCondVar(tm_vars.ml);
     if (NULL == tm_vars.cancel_timer)
     {
         goto failed;
     }
     PR_INIT_CLIST(&tm_vars.timer_queue);
     tm_vars.manager_thread = PR_CreateThread(
         PR_SYSTEM_THREAD, TimerManager, NULL, PR_PRIORITY_NORMAL,
         PR_LOCAL_THREAD, PR_UNJOINABLE_THREAD, 0);
     if (NULL == tm_vars.manager_thread)
     {
         goto failed;
     }
     return PR_SUCCESS;
 failed:
     if (NULL != tm_vars.cancel_timer)
     {
         PR_DestroyCondVar(tm_vars.cancel_timer);
     }
     if (NULL != tm_vars.new_timer)
     {
         PR_DestroyCondVar(tm_vars.new_timer);
     }
     if (NULL != tm_vars.ml)
     {
         PR_DestroyLock(tm_vars.ml);
     }
     return PR_FAILURE;
 }
 #endif /* WINNT */
 /******************************************************************/
 /******************************************************************/
 /************************ The private portion *********************/
 /******************************************************************/
 /******************************************************************/
 void _PR_InitMW(void)
 {
 #ifdef WINNT
     /*
      * We use NT 4's InterlockedCompareExchange() to operate
      * on PRMWStatus variables.
      */
     PR_ASSERT(sizeof(LONG) == sizeof(PRMWStatus));
     TimerInit();
 #endif
     mw_lock = PR_NewLock();
     PR_ASSERT(NULL != mw_lock);
     mw_state = PR_NEWZAP(_PRGlobalState);
     PR_ASSERT(NULL != mw_state);
     PR_INIT_CLIST(&mw_state->group_list);
     max_polling_interval = PR_MillisecondsToInterval(MAX_POLLING_INTERVAL);
 }  /* _PR_InitMW */
 void _PR_CleanupMW(void)
 {
     PR_DestroyLock(mw_lock);
     mw_lock = NULL;
     if (mw_state->group) {
         PR_DestroyWaitGroup(mw_state->group);
         /* mw_state->group is set to NULL as a side effect. */
     }
     PR_DELETE(mw_state);
 }  /* _PR_CleanupMW */
 static PRWaitGroup *MW_Init2(void)
 {
     PRWaitGroup *group = mw_state->group;  /* it's the null group */
     if (NULL == group)  /* there is this special case */
     {
         group = PR_CreateWaitGroup(_PR_DEFAULT_HASH_LENGTH);
         if (NULL == group) goto failed_alloc;
         PR_Lock(mw_lock);
         if (NULL == mw_state->group)
         {
             mw_state->group = group;
             group = NULL;
         }
         PR_Unlock(mw_lock);
         if (group != NULL) (void)PR_DestroyWaitGroup(group);
         group = mw_state->group;  /* somebody beat us to it */
     }
 failed_alloc:
     return group;  /* whatever */
 }  /* MW_Init2 */
 static _PR_HashStory MW_AddHashInternal(PRRecvWait *desc, _PRWaiterHash *hash)
 {
     /*
     ** The entries are put in the table using the fd (PRFileDesc*) of
     ** the receive descriptor as the key. This allows us to locate
     ** the appropriate entry aqain when the poll operation finishes.
     **
     ** The pointer to the file descriptor object is first divided by
     ** the natural alignment of a pointer in the belief that object
     ** will have at least that many zeros in the low order bits.
     ** This may not be a good assuption.
     **
     ** We try to put the entry in by rehashing _MW_REHASH_MAX times. After
     ** that we declare defeat and force the table to be reconstructed.
     ** Since some fds might be added more than once, won't that cause
     ** collisions even in an empty table?
     */
     PRIntn rehash = _MW_REHASH_MAX;
     PRRecvWait **waiter;
     PRUintn hidx = _MW_HASH(desc->fd, hash->length);
     PRUintn hoffset = 0;
     while (rehash-- > 0)
     {
         waiter = &hash->recv_wait;
         if (NULL == waiter[hidx])
         {
             waiter[hidx] = desc;
             hash->count += 1;
 #if 0
             printf("Adding 0x%x->0x%x ", desc, desc->fd);
             printf(
                 "table[%u:%u:*%u]: 0x%x->0x%x\n",
                 hidx, hash->count, hash->length, waiter[hidx], waiter[hidx]->fd);
 #endif
             return _prmw_success;
         }
         if (desc == waiter[hidx])
         {
             PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);  /* desc already in table */
             return _prmw_error;
         }
 #if 0
         printf("Failing 0x%x->0x%x ", desc, desc->fd);
         printf(
             "table[*%u:%u:%u]: 0x%x->0x%x\n",
             hidx, hash->count, hash->length, waiter[hidx], waiter[hidx]->fd);
 #endif
         if (0 == hoffset)
         {
             hoffset = _MW_HASH2(desc->fd, hash->length);
             PR_ASSERT(0 != hoffset);
         }
         hidx = (hidx + hoffset) % (hash->length);
     }
     return _prmw_rehash;
 }  /* MW_AddHashInternal */
 static _PR_HashStory MW_ExpandHashInternal(PRWaitGroup *group)
 {
     PRRecvWait **desc;
     PRUint32 pidx, length;
     _PRWaiterHash *newHash, *oldHash = group->waiter;
     PRBool retry;
     _PR_HashStory hrv;
     static const PRInt32 prime_number[] = {
         _PR_DEFAULT_HASH_LENGTH, 179, 521, 907, 1427,
 , 3917, 5021, 8219, 11549, 18911, 26711, 33749, 44771};
     PRUintn primes = (sizeof(prime_number) / sizeof(PRInt32));
     /* look up the next size we'd like to use for the hash table */
     for (pidx = 0; pidx < primes; ++pidx)
     {
         if (prime_number[pidx] == oldHash->length)
         {
             break;
         }
     }
     /* table size must be one of the prime numbers */
     PR_ASSERT(pidx < primes);
     /* if pidx == primes - 1, we can't expand the table any more */
     while (pidx < primes - 1)
     {
         /* next size */
         ++pidx;
         length = prime_number[pidx];
         /* allocate the new hash table and fill it in with the old */
         newHash = (_PRWaiterHash*)PR_CALLOC(
             sizeof(_PRWaiterHash) + (length * sizeof(PRRecvWait*)));
         if (NULL == newHash)
         {
             PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
             return _prmw_error;
         }
         newHash->length = length;
         retry = PR_FALSE;
         for (desc = &oldHash->recv_wait;
             newHash->count < oldHash->count; ++desc)
         {
             PR_ASSERT(desc < &oldHash->recv_wait + oldHash->length);
             if (NULL != *desc)
             {
                 hrv = MW_AddHashInternal(*desc, newHash);
                 PR_ASSERT(_prmw_error != hrv);
                 if (_prmw_success != hrv)
                 {
                     PR_DELETE(newHash);
                     retry = PR_TRUE;
                     break;
                 }
             }
         }
         if (retry) continue;
         PR_DELETE(group->waiter);
         group->waiter = newHash;
         group->p_timestamp += 1;
         return _prmw_success;
     }
     PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
     return _prmw_error;  /* we're hosed */
 }  /* MW_ExpandHashInternal */
 #ifndef WINNT
 static void _MW_DoneInternal(
     PRWaitGroup *group, PRRecvWait **waiter, PRMWStatus outcome)
 {
     /*
     ** Add this receive wait object to the list of finished I/O
     ** operations for this particular group. If there are other
     ** threads waiting on the group, notify one. If not, arrange
     ** for this thread to return.
     */
 #if 0
     printf("Removing 0x%x->0x%x\n", *waiter, (*waiter)->fd);
 #endif
     (*waiter)->outcome = outcome;
     PR_APPEND_LINK(&((*waiter)->internal), &group->io_ready);
     PR_NotifyCondVar(group->io_complete);
     PR_ASSERT(0 != group->waiter->count);
     group->waiter->count -= 1;
     *waiter = NULL;
 }  /* _MW_DoneInternal */
 #endif /* WINNT */
 static PRRecvWait **_MW_LookupInternal(PRWaitGroup *group, PRFileDesc *fd)
 {
     /*
     ** Find the receive wait object corresponding to the file descriptor.
     ** Only search the wait group specified.
     */
     PRRecvWait **desc;
     PRIntn rehash = _MW_REHASH_MAX;
     _PRWaiterHash *hash = group->waiter;
     PRUintn hidx = _MW_HASH(fd, hash->length);
     PRUintn hoffset = 0;
     while (rehash-- > 0)
     {
         desc = (&hash->recv_wait) + hidx;
         if ((*desc != NULL) && ((*desc)->fd == fd)) return desc;
         if (0 == hoffset)
         {
             hoffset = _MW_HASH2(fd, hash->length);
             PR_ASSERT(0 != hoffset);
         }
         hidx = (hidx + hoffset) % (hash->length);
     }
     return NULL;
 }  /* _MW_LookupInternal */
 #ifndef WINNT
 static PRStatus _MW_PollInternal(PRWaitGroup *group)
 {
     PRRecvWait **waiter;
     PRStatus rv = PR_FAILURE;
     PRInt32 count, count_ready;
     PRIntervalTime polling_interval;
     group->poller = PR_GetCurrentThread();
     while (PR_TRUE)
     {
         PRIntervalTime now, since_last_poll;
         PRPollDesc *poll_list;
         while (0 == group->waiter->count)
         {
             PRStatus st;
             st = PR_WaitCondVar(group->new_business, PR_INTERVAL_NO_TIMEOUT);
             if (_prmw_running != group->state)
             {
                 PR_SetError(PR_INVALID_STATE_ERROR, 0);
                 goto aborted;
             }
             if (_MW_ABORTED(st)) goto aborted;
         }
         /*
         ** There's something to do. See if our existing polling list
         ** is large enough for what we have to do?
         */
         while (group->polling_count < group->waiter->count)
         {
             PRUint32 old_count = group->waiter->count;
             PRUint32 new_count = PR_ROUNDUP(old_count, _PR_POLL_COUNT_FUDGE);
             PRSize new_size = sizeof(PRPollDesc) * new_count;
             PRPollDesc *old_polling_list = group->polling_list;
             PR_Unlock(group->ml);
             poll_list = (PRPollDesc*)PR_CALLOC(new_size);
             if (NULL == poll_list)
             {
                 PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
                 PR_Lock(group->ml);
                 goto failed_alloc;
             }
             if (NULL != old_polling_list)
                 PR_DELETE(old_polling_list);
             PR_Lock(group->ml);
             if (_prmw_running != group->state)
             {
                 PR_SetError(PR_INVALID_STATE_ERROR, 0);
                 goto aborted;
             }
             group->polling_list = poll_list;
             group->polling_count = new_count;
         }
         now = PR_IntervalNow();
         polling_interval = max_polling_interval;
         since_last_poll = now - group->last_poll;
         waiter = &group->waiter->recv_wait;
         poll_list = group->polling_list;
         for (count = 0; count < group->waiter->count; ++waiter)
         {
             PR_ASSERT(waiter < &group->waiter->recv_wait
                 + group->waiter->length);
             if (NULL != *waiter)  /* a live one! */
             {
                 if ((PR_INTERVAL_NO_TIMEOUT != (*waiter)->timeout)
                 && (since_last_poll >= (*waiter)->timeout))
                     _MW_DoneInternal(group, waiter, PR_MW_TIMEOUT);
                 else
                 {
                     if (PR_INTERVAL_NO_TIMEOUT != (*waiter)->timeout)
                     {
                         (*waiter)->timeout -= since_last_poll;
                         if ((*waiter)->timeout < polling_interval)
                             polling_interval = (*waiter)->timeout;
                     }
                     PR_ASSERT(poll_list < group->polling_list
                         + group->polling_count);
                     poll_list->fd = (*waiter)->fd;
                     poll_list->in_flags = PR_POLL_READ;
                     poll_list->out_flags = 0;
 #if 0
                     printf(
                         "Polling 0x%x[%d]: [fd: 0x%x, tmo: %u]\n",
                         poll_list, count, poll_list->fd, (*waiter)->timeout);
 #endif
                     poll_list += 1;
                     count += 1;
                 }
             }
         }
         PR_ASSERT(count == group->waiter->count);
         /*
         ** If there are no more threads waiting for completion,
         ** we need to return.
         */
         if ((!PR_CLIST_IS_EMPTY(&group->io_ready))
         && (1 == group->waiting_threads)) break;
         if (0 == count) continue;  /* wait for new business */
         group->last_poll = now;
         PR_Unlock(group->ml);
         count_ready = PR_Poll(group->polling_list, count, polling_interval);
         PR_Lock(group->ml);
         if (_prmw_running != group->state)
         {
             PR_SetError(PR_INVALID_STATE_ERROR, 0);
             goto aborted;
         }
         if (-1 == count_ready)
         {
             goto failed_poll;  /* that's a shame */
         }
         else if (0 < count_ready)
         {
             for (poll_list = group->polling_list; count > 0;
             poll_list++, count--)
             {
                 PR_ASSERT(
                     poll_list < group->polling_list + group->polling_count);
                 if (poll_list->out_flags != 0)
                 {
                     waiter = _MW_LookupInternal(group, poll_list->fd);
                     /*
                     ** If 'waiter' is NULL, that means the wait receive
                     ** descriptor has been canceled.
                     */
                     if (NULL != waiter)
                         _MW_DoneInternal(group, waiter, PR_MW_SUCCESS);
                 }
             }
         }
         /*
         ** If there are no more threads waiting for completion,
         ** we need to return.
         ** This thread was "borrowed" to do the polling, but it really
         ** belongs to the client.
         */
         if ((!PR_CLIST_IS_EMPTY(&group->io_ready))
         && (1 == group->waiting_threads)) break;
     }
     rv = PR_SUCCESS;
 aborted:
 failed_poll:
 failed_alloc:
     group->poller = NULL;  /* we were that, not we ain't */
     if ((_prmw_running == group->state) && (group->waiting_threads > 1))
     {
         /* Wake up one thread to become the new poller. */
         PR_NotifyCondVar(group->io_complete);
     }
     return rv;  /* we return with the lock held */
 }  /* _MW_PollInternal */
 #endif /* !WINNT */
 static PRMWGroupState MW_TestForShutdownInternal(PRWaitGroup *group)
 {
     PRMWGroupState rv = group->state;
     /*
     ** Looking at the group's fields is safe because
     ** once the group's state is no longer running, it
     ** cannot revert and there is a safe check on entry
     ** to make sure no more threads are made to wait.
     */
     if ((_prmw_stopping == rv)
     && (0 == group->waiting_threads))
     {
         rv = group->state = _prmw_stopped;
         PR_NotifyCondVar(group->mw_manage);
     }
     return rv;
 }  /* MW_TestForShutdownInternal */
 #ifndef WINNT
 static void _MW_InitialRecv(PRCList *io_ready)
 {
     PRRecvWait *desc = (PRRecvWait*)io_ready;
     if ((NULL == desc->buffer.start)
     || (0 == desc->buffer.length))
         desc->bytesRecv = 0;
     else
     {
         desc->bytesRecv = (desc->fd->methods->recv)(
             desc->fd, desc->buffer.start,
             desc->buffer.length, 0, desc->timeout);
         if (desc->bytesRecv < 0)  /* SetError should already be there */
             desc->outcome = PR_MW_FAILURE;
     }
 }  /* _MW_InitialRecv */
 #endif
 #ifdef WINNT
 static void NT_TimeProc(void *arg)
 {
     _MDOverlapped *overlapped = (_MDOverlapped *)arg;
     PRRecvWait *desc =  overlapped->data.mw.desc;
     PRFileDesc *bottom;
     if (InterlockedCompareExchange((LONG *)&desc->outcome,
         (LONG)PR_MW_TIMEOUT, (LONG)PR_MW_PENDING) != (LONG)PR_MW_PENDING)
     {
         /* This wait recv descriptor has already completed. */
         return;
     }
     /* close the osfd to abort the outstanding async io request */
     /* $$$$
     ** Little late to be checking if NSPR's on the bottom of stack,
     ** but if we don't check, we can't assert that the private data
     ** is what we think it is.
     ** $$$$
     */
     bottom = PR_GetIdentitiesLayer(desc->fd, PR_NSPR_IO_LAYER);
     PR_ASSERT(NULL != bottom);
     if (NULL != bottom)  /* now what!?!?! */
     {
         bottom->secret->state = _PR_FILEDESC_CLOSED;
         if (closesocket(bottom->secret->md.osfd) == SOCKET_ERROR)
         {
             fprintf(stderr, "closesocket failed: %d\n", WSAGetLastError());
             PR_ASSERT(!"What shall I do?");
         }
     }
     return;
 }  /* NT_TimeProc */
 static PRStatus NT_HashRemove(PRWaitGroup *group, PRFileDesc *fd)
 {
     PRRecvWait **waiter;
     _PR_MD_LOCK(&group->mdlock);
     waiter = _MW_LookupInternal(group, fd);
     if (NULL != waiter)
     {
         group->waiter->count -= 1;
         *waiter = NULL;
     }
     _PR_MD_UNLOCK(&group->mdlock);
     return (NULL != waiter) ? PR_SUCCESS : PR_FAILURE;
 }
 PRStatus NT_HashRemoveInternal(PRWaitGroup *group, PRFileDesc *fd)
 {
     PRRecvWait **waiter;
     waiter = _MW_LookupInternal(group, fd);
     if (NULL != waiter)
     {
         group->waiter->count -= 1;
         *waiter = NULL;
     }
     return (NULL != waiter) ? PR_SUCCESS : PR_FAILURE;
 }
 #endif /* WINNT */
 /******************************************************************/
 /******************************************************************/
 /********************** The public API portion ********************/
 /******************************************************************/
 /******************************************************************/
 PR_IMPLEMENT(PRStatus) PR_AddWaitFileDesc(
     PRWaitGroup *group, PRRecvWait *desc)
 {
     _PR_HashStory hrv;
     PRStatus rv = PR_FAILURE;
 #ifdef WINNT
     _MDOverlapped *overlapped;
     HANDLE hFile;
     BOOL bResult;
     DWORD dwError;
     PRFileDesc *bottom;
 #endif
     if (!_pr_initialized) _PR_ImplicitInitialization();
     if ((NULL == group) && (NULL == (group = MW_Init2())))
     {
         return rv;
     }
     PR_ASSERT(NULL != desc->fd);
     desc->outcome = PR_MW_PENDING;  /* nice, well known value */
     desc->bytesRecv = 0;  /* likewise, though this value is ambiguious */
     PR_Lock(group->ml);
     if (_prmw_running != group->state)
     {
         /* Not allowed to add after cancelling the group */
         desc->outcome = PR_MW_INTERRUPT;
         PR_SetError(PR_INVALID_STATE_ERROR, 0);
         PR_Unlock(group->ml);
         return rv;
     }
 #ifdef WINNT
     _PR_MD_LOCK(&group->mdlock);
 #endif
     /*
     ** If the waiter count is zero at this point, there's no telling
     ** how long we've been idle. Therefore, initialize the beginning
     ** of the timing interval. As long as the list doesn't go empty,
     ** it will maintain itself.
     */
     if (0 == group->waiter->count)
         group->last_poll = PR_IntervalNow();
     do
     {
         hrv = MW_AddHashInternal(desc, group->waiter);
         if (_prmw_rehash != hrv) break;
         hrv = MW_ExpandHashInternal(group);  /* gruesome */
         if (_prmw_success != hrv) break;
     } while (PR_TRUE);
 #ifdef WINNT
     _PR_MD_UNLOCK(&group->mdlock);
 #endif
     PR_NotifyCondVar(group->new_business);  /* tell the world */
     rv = (_prmw_success == hrv) ? PR_SUCCESS : PR_FAILURE;
     PR_Unlock(group->ml);
 #ifdef WINNT
     overlapped = PR_NEWZAP(_MDOverlapped);
     if (NULL == overlapped)
     {
         PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
         NT_HashRemove(group, desc->fd);
         return rv;
     }
     overlapped->ioModel = _MD_MultiWaitIO;
     overlapped->data.mw.desc = desc;
     overlapped->data.mw.group = group;
     if (desc->timeout != PR_INTERVAL_NO_TIMEOUT)
     {
         overlapped->data.mw.timer = CreateTimer(
             desc->timeout,
             NT_TimeProc,
             overlapped);
         if (0 == overlapped->data.mw.timer)
         {
             NT_HashRemove(group, desc->fd);
             PR_DELETE(overlapped);
             /*
              * XXX It appears that a maximum of 16 timer events can
              * be outstanding. GetLastError() returns 0 when I try it.
              */
             PR_SetError(PR_INSUFFICIENT_RESOURCES_ERROR, GetLastError());
             return PR_FAILURE;
         }
     }
     /* Reach to the bottom layer to get the OS fd */
     bottom = PR_GetIdentitiesLayer(desc->fd, PR_NSPR_IO_LAYER);
     PR_ASSERT(NULL != bottom);
     if (NULL == bottom)
     {
         PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
         return PR_FAILURE;
     }
     hFile = (HANDLE)bottom->secret->md.osfd;
     if (!bottom->secret->md.io_model_committed)
     {
         PRInt32 st;
         st = _md_Associate(hFile);
         PR_ASSERT(0 != st);
         bottom->secret->md.io_model_committed = PR_TRUE;
     }
     bResult = ReadFile(hFile,
         desc->buffer.start,
         (DWORD)desc->buffer.length,
         NULL,
         &overlapped->overlapped);
     if (FALSE == bResult && (dwError = GetLastError()) != ERROR_IO_PENDING)
     {
         if (desc->timeout != PR_INTERVAL_NO_TIMEOUT)
         {
             if (InterlockedCompareExchange((LONG *)&desc->outcome,
                 (LONG)PR_MW_FAILURE, (LONG)PR_MW_PENDING)
                 == (LONG)PR_MW_PENDING)
             {
                 CancelTimer(overlapped->data.mw.timer);
             }
             NT_HashRemove(group, desc->fd);
             PR_DELETE(overlapped);
         }
         _PR_MD_MAP_READ_ERROR(dwError);
         rv = PR_FAILURE;
     }
 #endif
     return rv;
 }  /* PR_AddWaitFileDesc */
 PR_IMPLEMENT(PRRecvWait*) PR_WaitRecvReady(PRWaitGroup *group)
 {
     PRCList *io_ready = NULL;
 #ifdef WINNT
     PRThread *me = _PR_MD_CURRENT_THREAD();
     _MDOverlapped *overlapped;
 #endif
     if (!_pr_initialized) _PR_ImplicitInitialization();
     if ((NULL == group) && (NULL == (group = MW_Init2()))) goto failed_init;
     PR_Lock(group->ml);
     if (_prmw_running != group->state)
     {
         PR_SetError(PR_INVALID_STATE_ERROR, 0);
         goto invalid_state;
     }
     group->waiting_threads += 1;  /* the polling thread is counted */
 #ifdef WINNT
     _PR_MD_LOCK(&group->mdlock);
     while (PR_CLIST_IS_EMPTY(&group->io_ready))
     {
         _PR_THREAD_LOCK(me);
         me->state = _PR_IO_WAIT;
         PR_APPEND_LINK(&me->waitQLinks, &group->wait_list);
         if (!_PR_IS_NATIVE_THREAD(me))
         {
             _PR_SLEEPQ_LOCK(me->cpu);
             _PR_ADD_SLEEPQ(me, PR_INTERVAL_NO_TIMEOUT);
             _PR_SLEEPQ_UNLOCK(me->cpu);
         }
         _PR_THREAD_UNLOCK(me);
         _PR_MD_UNLOCK(&group->mdlock);
         PR_Unlock(group->ml);
         _PR_MD_WAIT(me, PR_INTERVAL_NO_TIMEOUT);
         me->state = _PR_RUNNING;
         PR_Lock(group->ml);
         _PR_MD_LOCK(&group->mdlock);
         if (_PR_PENDING_INTERRUPT(me)) {
             PR_REMOVE_LINK(&me->waitQLinks);
             _PR_MD_UNLOCK(&group->mdlock);
             me->flags &= ~_PR_INTERRUPT;
             me->io_suspended = PR_FALSE;
             PR_SetError(PR_PENDING_INTERRUPT_ERROR, 0);
             goto aborted;
         }
     }
     io_ready = PR_LIST_HEAD(&group->io_ready);
     PR_ASSERT(io_ready != NULL);
     PR_REMOVE_LINK(io_ready);
     _PR_MD_UNLOCK(&group->mdlock);
     overlapped = (_MDOverlapped *)
         ((char *)io_ready - offsetof(_MDOverlapped, data));
     io_ready = &overlapped->data.mw.desc->internal;
 #else
     do
     {
         /*
         ** If the I/O ready list isn't empty, have this thread
         ** return with the first receive wait object that's available.
         */
         if (PR_CLIST_IS_EMPTY(&group->io_ready))
         {
             /*
             ** Is there a polling thread yet? If not, grab this thread
             ** and use it.
             */
             if (NULL == group->poller)
             {
                 /*
                 ** This thread will stay do polling until it becomes the only one
                 ** left to service a completion. Then it will return and there will
                 ** be none left to actually poll or to run completions.
                 **
                 ** The polling function should only return w/ failure or
                 ** with some I/O ready.
                 */
                 if (PR_FAILURE == _MW_PollInternal(group)) goto failed_poll;
             }
             else
             {
                 /*
                 ** There are four reasons a thread can be awakened from
                 ** a wait on the io_complete condition variable.
                 ** 1. Some I/O has completed, i.e., the io_ready list
                 **    is nonempty.
                 ** 2. The wait group is canceled.
                 ** 3. The thread is interrupted.
                 ** 4. The current polling thread has to leave and needs
                 **    a replacement.
                 ** The logic to find a new polling thread is made more
                 ** complicated by all the other possible events.
                 ** I tried my best to write the logic clearly, but
                 ** it is still full of if's with continue and goto.
                 */
                 PRStatus st;
                 do
                 {
                     st = PR_WaitCondVar(group->io_complete, PR_INTERVAL_NO_TIMEOUT);
                     if (_prmw_running != group->state)
                     {
                         PR_SetError(PR_INVALID_STATE_ERROR, 0);
                         goto aborted;
                     }
                     if (_MW_ABORTED(st) || (NULL == group->poller)) break;
                 } while (PR_CLIST_IS_EMPTY(&group->io_ready));
                 /*
                 ** The thread is interrupted and has to leave.  It might
                 ** have also been awakened to process ready i/o or be the
                 ** new poller.  To be safe, if either condition is true,
                 ** we awaken another thread to take its place.
                 */
                 if (_MW_ABORTED(st))
                 {
                     if ((NULL == group->poller
                     || !PR_CLIST_IS_EMPTY(&group->io_ready))
                     && group->waiting_threads > 1)
                         PR_NotifyCondVar(group->io_complete);
                     goto aborted;
                 }
                 /*
                 ** A new poller is needed, but can I be the new poller?
                 ** If there is no i/o ready, sure.  But if there is any
                 ** i/o ready, it has a higher priority.  I want to
                 ** process the ready i/o first and wake up another
                 ** thread to be the new poller.
                 */
                 if (NULL == group->poller)
                 {
                     if (PR_CLIST_IS_EMPTY(&group->io_ready))
                         continue;
                     if (group->waiting_threads > 1)
                         PR_NotifyCondVar(group->io_complete);
                 }
             }
             PR_ASSERT(!PR_CLIST_IS_EMPTY(&group->io_ready));
         }
         io_ready = PR_LIST_HEAD(&group->io_ready);
         PR_NotifyCondVar(group->io_taken);
         PR_ASSERT(io_ready != NULL);
         PR_REMOVE_LINK(io_ready);
     } while (NULL == io_ready);
 failed_poll:
 #endif
 aborted:
     group->waiting_threads -= 1;
 invalid_state:
     (void)MW_TestForShutdownInternal(group);
     PR_Unlock(group->ml);
 failed_init:
     if (NULL != io_ready)
     {
         /* If the operation failed, record the reason why */
         switch (((PRRecvWait*)io_ready)->outcome)
         {
             case PR_MW_PENDING:
                 PR_ASSERT(0);
                 break;
             case PR_MW_SUCCESS:
 #ifndef WINNT
                 _MW_InitialRecv(io_ready);
 #endif
                 break;
 #ifdef WINNT
             case PR_MW_FAILURE:
                 _PR_MD_MAP_READ_ERROR(overlapped->data.mw.error);
                 break;
 #endif
             case PR_MW_TIMEOUT:
                 PR_SetError(PR_IO_TIMEOUT_ERROR, 0);
                 break;
             case PR_MW_INTERRUPT:
                 PR_SetError(PR_PENDING_INTERRUPT_ERROR, 0);
                 break;
             default: break;
         }
 #ifdef WINNT
         if (NULL != overlapped->data.mw.timer)
         {
             PR_ASSERT(PR_INTERVAL_NO_TIMEOUT
                 != overlapped->data.mw.desc->timeout);
             CancelTimer(overlapped->data.mw.timer);
         }
         else
         {
             PR_ASSERT(PR_INTERVAL_NO_TIMEOUT
                 == overlapped->data.mw.desc->timeout);
         }
         PR_DELETE(overlapped);
 #endif
     }
     return (PRRecvWait*)io_ready;
 }  /* PR_WaitRecvReady */
 PR_IMPLEMENT(PRStatus) PR_CancelWaitFileDesc(PRWaitGroup *group, PRRecvWait *desc)
 {
 #if !defined(WINNT)
     PRRecvWait **recv_wait;
 #endif
     PRStatus rv = PR_SUCCESS;
     if (NULL == group) group = mw_state->group;
     PR_ASSERT(NULL != group);
     if (NULL == group)
     {
         PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
         return PR_FAILURE;
     }
     PR_Lock(group->ml);
     if (_prmw_running != group->state)
     {
         PR_SetError(PR_INVALID_STATE_ERROR, 0);
         rv = PR_FAILURE;
         goto unlock;
     }
 #ifdef WINNT
     if (InterlockedCompareExchange((LONG *)&desc->outcome,
         (LONG)PR_MW_INTERRUPT, (LONG)PR_MW_PENDING) == (LONG)PR_MW_PENDING)
     {
         PRFileDesc *bottom = PR_GetIdentitiesLayer(desc->fd, PR_NSPR_IO_LAYER);
         PR_ASSERT(NULL != bottom);
         if (NULL == bottom)
         {
             PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
             goto unlock;
         }
         bottom->secret->state = _PR_FILEDESC_CLOSED;
 #if 0
         fprintf(stderr, "cancel wait recv: closing socket\n");
 #endif
         if (closesocket(bottom->secret->md.osfd) == SOCKET_ERROR)
         {
             fprintf(stderr, "closesocket failed: %d\n", WSAGetLastError());
             exit(1);
         }
     }
 #else
     if (NULL != (recv_wait = _MW_LookupInternal(group, desc->fd)))
     {
         /* it was in the wait table */
         _MW_DoneInternal(group, recv_wait, PR_MW_INTERRUPT);
         goto unlock;
     }
     if (!PR_CLIST_IS_EMPTY(&group->io_ready))
     {
         /* is it already complete? */
         PRCList *head = PR_LIST_HEAD(&group->io_ready);
         do
         {
             PRRecvWait *done = (PRRecvWait*)head;
             if (done == desc) goto unlock;
             head = PR_NEXT_LINK(head);
         } while (head != &group->io_ready);
     }
     PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
     rv = PR_FAILURE;
 #endif
 unlock:
     PR_Unlock(group->ml);
     return rv;
 }  /* PR_CancelWaitFileDesc */
 PR_IMPLEMENT(PRRecvWait*) PR_CancelWaitGroup(PRWaitGroup *group)
 {
     PRRecvWait **desc;
     PRRecvWait *recv_wait = NULL;
 #ifdef WINNT
     _MDOverlapped *overlapped;
     PRRecvWait **end;
     PRThread *me = _PR_MD_CURRENT_THREAD();
 #endif
     if (NULL == group) group = mw_state->group;
     PR_ASSERT(NULL != group);
     if (NULL == group)
     {
         PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
         return NULL;
     }
     PR_Lock(group->ml);
     if (_prmw_stopped != group->state)
     {
         if (_prmw_running == group->state)
             group->state = _prmw_stopping;  /* so nothing new comes in */
         if (0 == group->waiting_threads)  /* is there anybody else? */
             group->state = _prmw_stopped;  /* we can stop right now */
         else
         {
             PR_NotifyAllCondVar(group->new_business);
             PR_NotifyAllCondVar(group->io_complete);
         }
         while (_prmw_stopped != group->state)
             (void)PR_WaitCondVar(group->mw_manage, PR_INTERVAL_NO_TIMEOUT);
     }
 #ifdef WINNT
     _PR_MD_LOCK(&group->mdlock);
 #endif
     /* make all the existing descriptors look done/interrupted */
 #ifdef WINNT
     end = &group->waiter->recv_wait + group->waiter->length;
     for (desc = &group->waiter->recv_wait; desc < end; ++desc)
     {
         if (NULL != *desc)
         {
             if (InterlockedCompareExchange((LONG *)&(*desc)->outcome,
                 (LONG)PR_MW_INTERRUPT, (LONG)PR_MW_PENDING)
                 == (LONG)PR_MW_PENDING)
             {
                 PRFileDesc *bottom = PR_GetIdentitiesLayer(
                     (*desc)->fd, PR_NSPR_IO_LAYER);
                 PR_ASSERT(NULL != bottom);
                 if (NULL == bottom)
                 {
                     PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
                     goto invalid_arg;
                 }
                 bottom->secret->state = _PR_FILEDESC_CLOSED;
 #if 0
                 fprintf(stderr, "cancel wait group: closing socket\n");
 #endif
                 if (closesocket(bottom->secret->md.osfd) == SOCKET_ERROR)
                 {
                     fprintf(stderr, "closesocket failed: %d\n",
                         WSAGetLastError());
                     exit(1);
                 }
             }
         }
     }
     while (group->waiter->count > 0)
     {
         _PR_THREAD_LOCK(me);
         me->state = _PR_IO_WAIT;
         PR_APPEND_LINK(&me->waitQLinks, &group->wait_list);
         if (!_PR_IS_NATIVE_THREAD(me))
         {
             _PR_SLEEPQ_LOCK(me->cpu);
             _PR_ADD_SLEEPQ(me, PR_INTERVAL_NO_TIMEOUT);
             _PR_SLEEPQ_UNLOCK(me->cpu);
         }
         _PR_THREAD_UNLOCK(me);
         _PR_MD_UNLOCK(&group->mdlock);
         PR_Unlock(group->ml);
         _PR_MD_WAIT(me, PR_INTERVAL_NO_TIMEOUT);
         me->state = _PR_RUNNING;
         PR_Lock(group->ml);
         _PR_MD_LOCK(&group->mdlock);
     }
 #else
     for (desc = &group->waiter->recv_wait; group->waiter->count > 0; ++desc)
     {
         PR_ASSERT(desc < &group->waiter->recv_wait + group->waiter->length);
         if (NULL != *desc)
             _MW_DoneInternal(group, desc, PR_MW_INTERRUPT);
     }
 #endif
     /* take first element of finished list and return it or NULL */
     if (PR_CLIST_IS_EMPTY(&group->io_ready))
         PR_SetError(PR_GROUP_EMPTY_ERROR, 0);
     else
     {
         PRCList *head = PR_LIST_HEAD(&group->io_ready);
         PR_REMOVE_AND_INIT_LINK(head);
 #ifdef WINNT
         overlapped = (_MDOverlapped *)
             ((char *)head - offsetof(_MDOverlapped, data));
         head = &overlapped->data.mw.desc->internal;
         if (NULL != overlapped->data.mw.timer)
         {
             PR_ASSERT(PR_INTERVAL_NO_TIMEOUT
                 != overlapped->data.mw.desc->timeout);
             CancelTimer(overlapped->data.mw.timer);
         }
         else
         {
             PR_ASSERT(PR_INTERVAL_NO_TIMEOUT
                 == overlapped->data.mw.desc->timeout);
         }
         PR_DELETE(overlapped);
 #endif
         recv_wait = (PRRecvWait*)head;
     }
 #ifdef WINNT
 invalid_arg:
     _PR_MD_UNLOCK(&group->mdlock);
 #endif
     PR_Unlock(group->ml);
     return recv_wait;
 }  /* PR_CancelWaitGroup */
 PR_IMPLEMENT(PRWaitGroup*) PR_CreateWaitGroup(PRInt32 size /* ignored */)
 {
     PRWaitGroup *wg;
     if (NULL == (wg = PR_NEWZAP(PRWaitGroup)))
     {
         PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
         goto failed;
     }
     /* the wait group itself */
     wg->ml = PR_NewLock();
     if (NULL == wg->ml) goto failed_lock;
     wg->io_taken = PR_NewCondVar(wg->ml);
     if (NULL == wg->io_taken) goto failed_cvar0;
     wg->io_complete = PR_NewCondVar(wg->ml);
     if (NULL == wg->io_complete) goto failed_cvar1;
     wg->new_business = PR_NewCondVar(wg->ml);
     if (NULL == wg->new_business) goto failed_cvar2;
     wg->mw_manage = PR_NewCondVar(wg->ml);
     if (NULL == wg->mw_manage) goto failed_cvar3;
     PR_INIT_CLIST(&wg->group_link);
     PR_INIT_CLIST(&wg->io_ready);
     /* the waiters sequence */
     wg->waiter = (_PRWaiterHash*)PR_CALLOC(
         sizeof(_PRWaiterHash) +
         (_PR_DEFAULT_HASH_LENGTH * sizeof(PRRecvWait*)));
     if (NULL == wg->waiter)
     {
         PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
         goto failed_waiter;
     }
     wg->waiter->count = 0;
     wg->waiter->length = _PR_DEFAULT_HASH_LENGTH;
 #ifdef WINNT
     _PR_MD_NEW_LOCK(&wg->mdlock);
     PR_INIT_CLIST(&wg->wait_list);
 #endif /* WINNT */
     PR_Lock(mw_lock);
     PR_APPEND_LINK(&wg->group_link, &mw_state->group_list);
     PR_Unlock(mw_lock);
     return wg;
 failed_waiter:
     PR_DestroyCondVar(wg->mw_manage);
 failed_cvar3:
     PR_DestroyCondVar(wg->new_business);
 failed_cvar2:
     PR_DestroyCondVar(wg->io_complete);
 failed_cvar1:
     PR_DestroyCondVar(wg->io_taken);
 failed_cvar0:
     PR_DestroyLock(wg->ml);
 failed_lock:
     PR_DELETE(wg);
     wg = NULL;
 failed:
     return wg;
 }  /* MW_CreateWaitGroup */
 PR_IMPLEMENT(PRStatus) PR_DestroyWaitGroup(PRWaitGroup *group)
 {
     PRStatus rv = PR_SUCCESS;
     if (NULL == group) group = mw_state->group;
     PR_ASSERT(NULL != group);
     if (NULL != group)
     {
         PR_Lock(group->ml);
         if ((group->waiting_threads == 0)
         && (group->waiter->count == 0)
         && PR_CLIST_IS_EMPTY(&group->io_ready))
         {
             group->state = _prmw_stopped;
         }
         else
         {
             PR_SetError(PR_INVALID_STATE_ERROR, 0);
             rv = PR_FAILURE;
         }
         PR_Unlock(group->ml);
         if (PR_FAILURE == rv) return rv;
         PR_Lock(mw_lock);
         PR_REMOVE_LINK(&group->group_link);
         PR_Unlock(mw_lock);
 #ifdef WINNT
         /*
          * XXX make sure wait_list is empty and waiter is empty.
          * These must be checked while holding mdlock.
          */
         _PR_MD_FREE_LOCK(&group->mdlock);
 #endif
         PR_DELETE(group->waiter);
         PR_DELETE(group->polling_list);
         PR_DestroyCondVar(group->mw_manage);
         PR_DestroyCondVar(group->new_business);
         PR_DestroyCondVar(group->io_complete);
         PR_DestroyCondVar(group->io_taken);
         PR_DestroyLock(group->ml);
         if (group == mw_state->group) mw_state->group = NULL;
         PR_DELETE(group);
     }
     else
     {
         /* The default wait group is not created yet. */
         PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
         rv = PR_FAILURE;
     }
     return rv;
 }  /* PR_DestroyWaitGroup */
 /**********************************************************************
 ***********************************************************************
 ******************** Wait group enumerations **************************
 ***********************************************************************
 **********************************************************************/
 PR_IMPLEMENT(PRMWaitEnumerator*) PR_CreateMWaitEnumerator(PRWaitGroup *group)
 {
     PRMWaitEnumerator *enumerator = PR_NEWZAP(PRMWaitEnumerator);
     if (NULL == enumerator) PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
     else
     {
         enumerator->group = group;
         enumerator->seal = _PR_ENUM_SEALED;
     }
     return enumerator;
 }  /* PR_CreateMWaitEnumerator */
 PR_IMPLEMENT(PRStatus) PR_DestroyMWaitEnumerator(PRMWaitEnumerator* enumerator)
 {
     PR_ASSERT(NULL != enumerator);
     PR_ASSERT(_PR_ENUM_SEALED == enumerator->seal);
     if ((NULL == enumerator) || (_PR_ENUM_SEALED != enumerator->seal))
     {
         PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
         return PR_FAILURE;
     }
     enumerator->seal = _PR_ENUM_UNSEALED;
     PR_Free(enumerator);
     return PR_SUCCESS;
 }  /* PR_DestroyMWaitEnumerator */
 PR_IMPLEMENT(PRRecvWait*) PR_EnumerateWaitGroup(
     PRMWaitEnumerator *enumerator, const PRRecvWait *previous)
 {
     PRRecvWait *result = NULL;
     /* entry point sanity checking */
     PR_ASSERT(NULL != enumerator);
     PR_ASSERT(_PR_ENUM_SEALED == enumerator->seal);
     if ((NULL == enumerator)
     || (_PR_ENUM_SEALED != enumerator->seal)) goto bad_argument;
     /* beginning of enumeration */
     if (NULL == previous)
     {
         if (NULL == enumerator->group)
         {
             enumerator->group = mw_state->group;
             if (NULL == enumerator->group)
             {
                 PR_SetError(PR_GROUP_EMPTY_ERROR, 0);
                 return NULL;
             }
         }
         enumerator->waiter = &enumerator->group->waiter->recv_wait;
         enumerator->p_timestamp = enumerator->group->p_timestamp;
         enumerator->thread = PR_GetCurrentThread();
         enumerator->index = 0;
     }
     /* continuing an enumeration */
     else
     {
         PRThread *me = PR_GetCurrentThread();
         PR_ASSERT(me == enumerator->thread);
         if (me != enumerator->thread) goto bad_argument;
         /* need to restart the enumeration */
         if (enumerator->p_timestamp != enumerator->group->p_timestamp)
             return PR_EnumerateWaitGroup(enumerator, NULL);
     }
     /* actually progress the enumeration */
 #if defined(WINNT)
     _PR_MD_LOCK(&enumerator->group->mdlock);
 #else
     PR_Lock(enumerator->group->ml);
 #endif
     while (enumerator->index++ < enumerator->group->waiter->length)
     {
         if (NULL != (result = *(enumerator->waiter)++)) break;
     }
 #if defined(WINNT)
     _PR_MD_UNLOCK(&enumerator->group->mdlock);
 #else
     PR_Unlock(enumerator->group->ml);
 #endif
     return result;  /* what we live for */
 bad_argument:
     PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
     return NULL;  /* probably ambiguous */
 }  /* PR_EnumerateWaitGroup */
 /* prmwait.c */

The Tor Browser / annotate

nsprpub/pr/src/io/prmwait.c@6474c204b198 (annotated)

nsprpub/pr/src/io/prmwait.c