Index: mozilla/nsprpub/pr/src/md/windows/w95cv.c |
=================================================================== |
--- mozilla/nsprpub/pr/src/md/windows/w95cv.c (revision 191424) |
+++ mozilla/nsprpub/pr/src/md/windows/w95cv.c (working copy) |
@@ -1,315 +0,0 @@ |
-/* -*- 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/. */ |
- |
-/* |
- * w95cv.c -- Windows 95 Machine-Dependent Code for Condition Variables |
- * |
- * We implement our own condition variable wait queue. Each thread |
- * has a semaphore object (thread->md.blocked_sema) to block on while |
- * waiting on a condition variable. |
- * |
- * We use a deferred condition notify algorithm. When PR_NotifyCondVar |
- * or PR_NotifyAllCondVar is called, the condition notifies are simply |
- * recorded in the _MDLock structure. We defer the condition notifies |
- * until right after we unlock the lock. This way the awakened threads |
- * have a better chance to reaquire the lock. |
- */ |
- |
-#include "primpl.h" |
- |
-/* |
- * AddThreadToCVWaitQueueInternal -- |
- * |
- * Add the thread to the end of the condition variable's wait queue. |
- * The CV's lock must be locked when this function is called. |
- */ |
- |
-static void |
-AddThreadToCVWaitQueueInternal(PRThread *thred, struct _MDCVar *cv) |
-{ |
- PR_ASSERT((cv->waitTail != NULL && cv->waitHead != NULL) |
- || (cv->waitTail == NULL && cv->waitHead == NULL)); |
- cv->nwait += 1; |
- thred->md.inCVWaitQueue = PR_TRUE; |
- thred->md.next = NULL; |
- thred->md.prev = cv->waitTail; |
- if (cv->waitHead == NULL) { |
- cv->waitHead = thred; |
- } else { |
- cv->waitTail->md.next = thred; |
- } |
- cv->waitTail = thred; |
-} |
- |
-/* |
- * md_UnlockAndPostNotifies -- |
- * |
- * Unlock the lock, and then do the deferred condition notifies. |
- * If waitThred and waitCV are not NULL, waitThred is added to |
- * the wait queue of waitCV before the lock is unlocked. |
- * |
- * This function is called by _PR_MD_WAIT_CV and _PR_MD_UNLOCK, |
- * the two places where a lock is unlocked. |
- */ |
-static void |
-md_UnlockAndPostNotifies( |
- _MDLock *lock, |
- PRThread *waitThred, |
- _MDCVar *waitCV) |
-{ |
- PRIntn index; |
- _MDNotified post; |
- _MDNotified *notified, *prev = NULL; |
- |
- /* |
- * Time to actually notify any conditions that were affected |
- * while the lock was held. Get a copy of the list that's in |
- * the lock structure and then zero the original. If it's |
- * linked to other such structures, we own that storage. |
- */ |
- post = lock->notified; /* a safe copy; we own the lock */ |
- |
-#if defined(DEBUG) |
- ZeroMemory(&lock->notified, sizeof(_MDNotified)); /* reset */ |
-#else |
- lock->notified.length = 0; /* these are really sufficient */ |
- lock->notified.link = NULL; |
-#endif |
- |
- /* |
- * Figure out how many threads we need to wake up. |
- */ |
- notified = &post; /* this is where we start */ |
- do { |
- for (index = 0; index < notified->length; ++index) { |
- _MDCVar *cv = notified->cv[index].cv; |
- PRThread *thred; |
- int i; |
- |
- /* Fast special case: no waiting threads */ |
- if (cv->waitHead == NULL) { |
- notified->cv[index].notifyHead = NULL; |
- continue; |
- } |
- |
- /* General case */ |
- if (-1 == notified->cv[index].times) { |
- /* broadcast */ |
- thred = cv->waitHead; |
- while (thred != NULL) { |
- thred->md.inCVWaitQueue = PR_FALSE; |
- thred = thred->md.next; |
- } |
- notified->cv[index].notifyHead = cv->waitHead; |
- cv->waitHead = cv->waitTail = NULL; |
- cv->nwait = 0; |
- } else { |
- thred = cv->waitHead; |
- i = notified->cv[index].times; |
- while (thred != NULL && i > 0) { |
- thred->md.inCVWaitQueue = PR_FALSE; |
- thred = thred->md.next; |
- i--; |
- } |
- notified->cv[index].notifyHead = cv->waitHead; |
- cv->waitHead = thred; |
- if (cv->waitHead == NULL) { |
- cv->waitTail = NULL; |
- } else { |
- if (cv->waitHead->md.prev != NULL) { |
- cv->waitHead->md.prev->md.next = NULL; |
- cv->waitHead->md.prev = NULL; |
- } |
- } |
- cv->nwait -= notified->cv[index].times - i; |
- } |
- } |
- notified = notified->link; |
- } while (NULL != notified); |
- |
- if (waitThred) { |
- AddThreadToCVWaitQueueInternal(waitThred, waitCV); |
- } |
- |
- /* Release the lock before notifying */ |
- LeaveCriticalSection(&lock->mutex); |
- |
- notified = &post; /* this is where we start */ |
- do { |
- for (index = 0; index < notified->length; ++index) { |
- PRThread *thred; |
- PRThread *next; |
- |
- thred = notified->cv[index].notifyHead; |
- while (thred != NULL) { |
- BOOL rv; |
- |
- next = thred->md.next; |
- thred->md.prev = thred->md.next = NULL; |
- |
- rv = ReleaseSemaphore(thred->md.blocked_sema, 1, NULL); |
- PR_ASSERT(rv != 0); |
- thred = next; |
- } |
- } |
- prev = notified; |
- notified = notified->link; |
- if (&post != prev) PR_DELETE(prev); |
- } while (NULL != notified); |
-} |
- |
-/* |
- * Notifies just get posted to the protecting mutex. The |
- * actual notification is done when the lock is released so that |
- * MP systems don't contend for a lock that they can't have. |
- */ |
-static void md_PostNotifyToCvar(_MDCVar *cvar, _MDLock *lock, |
- PRBool broadcast) |
-{ |
- PRIntn index = 0; |
- _MDNotified *notified = &lock->notified; |
- |
- while (1) { |
- for (index = 0; index < notified->length; ++index) { |
- if (notified->cv[index].cv == cvar) { |
- if (broadcast) { |
- notified->cv[index].times = -1; |
- } else if (-1 != notified->cv[index].times) { |
- notified->cv[index].times += 1; |
- } |
- return; |
- } |
- } |
- /* if not full, enter new CV in this array */ |
- if (notified->length < _MD_CV_NOTIFIED_LENGTH) break; |
- |
- /* if there's no link, create an empty array and link it */ |
- if (NULL == notified->link) { |
- notified->link = PR_NEWZAP(_MDNotified); |
- } |
- |
- notified = notified->link; |
- } |
- |
- /* A brand new entry in the array */ |
- notified->cv[index].times = (broadcast) ? -1 : 1; |
- notified->cv[index].cv = cvar; |
- notified->length += 1; |
-} |
- |
-/* |
- * _PR_MD_NEW_CV() -- Creating new condition variable |
- * ... Solaris uses cond_init() in similar function. |
- * |
- * returns: -1 on failure |
- * 0 when it succeeds. |
- * |
- */ |
-PRInt32 |
-_PR_MD_NEW_CV(_MDCVar *cv) |
-{ |
- cv->magic = _MD_MAGIC_CV; |
- /* |
- * The waitHead, waitTail, and nwait fields are zeroed |
- * when the PRCondVar structure is created. |
- */ |
- return 0; |
-} |
- |
-void _PR_MD_FREE_CV(_MDCVar *cv) |
-{ |
- cv->magic = (PRUint32)-1; |
- return; |
-} |
- |
-/* |
- * _PR_MD_WAIT_CV() -- Wait on condition variable |
- */ |
-void _PR_MD_WAIT_CV(_MDCVar *cv, _MDLock *lock, PRIntervalTime timeout ) |
-{ |
- PRThread *thred = _PR_MD_CURRENT_THREAD(); |
- DWORD rv; |
- DWORD msecs = (timeout == PR_INTERVAL_NO_TIMEOUT) ? |
- INFINITE : PR_IntervalToMilliseconds(timeout); |
- |
- /* |
- * If we have pending notifies, post them now. |
- */ |
- if (0 != lock->notified.length) { |
- md_UnlockAndPostNotifies(lock, thred, cv); |
- } else { |
- AddThreadToCVWaitQueueInternal(thred, cv); |
- LeaveCriticalSection(&lock->mutex); |
- } |
- |
- /* Wait for notification or timeout; don't really care which */ |
- rv = WaitForSingleObject(thred->md.blocked_sema, msecs); |
- |
- EnterCriticalSection(&(lock->mutex)); |
- |
- PR_ASSERT(rv != WAIT_ABANDONED); |
- PR_ASSERT(rv != WAIT_FAILED); |
- PR_ASSERT(rv != WAIT_OBJECT_0 || thred->md.inCVWaitQueue == PR_FALSE); |
- |
- if (rv == WAIT_TIMEOUT) { |
- if (thred->md.inCVWaitQueue) { |
- PR_ASSERT((cv->waitTail != NULL && cv->waitHead != NULL) |
- || (cv->waitTail == NULL && cv->waitHead == NULL)); |
- cv->nwait -= 1; |
- thred->md.inCVWaitQueue = PR_FALSE; |
- if (cv->waitHead == thred) { |
- cv->waitHead = thred->md.next; |
- if (cv->waitHead == NULL) { |
- cv->waitTail = NULL; |
- } else { |
- cv->waitHead->md.prev = NULL; |
- } |
- } else { |
- PR_ASSERT(thred->md.prev != NULL); |
- thred->md.prev->md.next = thred->md.next; |
- if (thred->md.next != NULL) { |
- thred->md.next->md.prev = thred->md.prev; |
- } else { |
- PR_ASSERT(cv->waitTail == thred); |
- cv->waitTail = thred->md.prev; |
- } |
- } |
- thred->md.next = thred->md.prev = NULL; |
- } else { |
- /* |
- * This thread must have been notified, but the |
- * ReleaseSemaphore call happens after WaitForSingleObject |
- * times out. Wait on the semaphore again to make it |
- * non-signaled. We assume this wait won't take long. |
- */ |
- rv = WaitForSingleObject(thred->md.blocked_sema, INFINITE); |
- PR_ASSERT(rv == WAIT_OBJECT_0); |
- } |
- } |
- PR_ASSERT(thred->md.inCVWaitQueue == PR_FALSE); |
- return; |
-} /* --- end _PR_MD_WAIT_CV() --- */ |
- |
-void _PR_MD_NOTIFY_CV(_MDCVar *cv, _MDLock *lock) |
-{ |
- md_PostNotifyToCvar(cv, lock, PR_FALSE); |
- return; |
-} |
- |
-void _PR_MD_NOTIFYALL_CV(_MDCVar *cv, _MDLock *lock) |
-{ |
- md_PostNotifyToCvar(cv, lock, PR_TRUE); |
- return; |
-} |
- |
-void _PR_MD_UNLOCK(_MDLock *lock) |
-{ |
- if (0 != lock->notified.length) { |
- md_UnlockAndPostNotifies(lock, NULL, NULL); |
- } else { |
- LeaveCriticalSection(&lock->mutex); |
- } |
- return; |
-} |