void
Tcl_ConditionWait(
Tcl_Condition *condPtr, /* Really (pthread_cond_t **) */
Tcl_Mutex *mutexPtr, /* Really (pthread_mutex_t **) */
Tcl_Time *timePtr) /* Timeout on waiting period */
{
pthread_cond_t *pcondPtr;
pthread_mutex_t *pmutexPtr;
struct timespec ptime;
if (*condPtr == NULL) {
MASTER_LOCK;
/*
* Double check inside mutex to avoid race, then initialize condition
* variable if necessary.
*/
if (*condPtr == NULL) {
pcondPtr = (pthread_cond_t *) ckalloc(sizeof(pthread_cond_t));
pthread_cond_init(pcondPtr, NULL);
*condPtr = (Tcl_Condition)pcondPtr;
TclRememberCondition(condPtr);
}
MASTER_UNLOCK;
}
pmutexPtr = *((pthread_mutex_t **)mutexPtr);
pcondPtr = *((pthread_cond_t **)condPtr);
if (timePtr == NULL) {
pthread_cond_wait(pcondPtr, pmutexPtr);
} else {
Tcl_Time now;
/*
* Make sure to take into account the microsecond component of the
* current time, including possible overflow situations. [Bug #411603]
*/
Tcl_GetTime(&now);
ptime.tv_sec = timePtr->sec + now.sec +
(timePtr->usec + now.usec) / 1000000;
ptime.tv_nsec = 1000 * ((timePtr->usec + now.usec) % 1000000);
pthread_cond_timedwait(pcondPtr, pmutexPtr, &ptime);
}
}
void
Tcl_ConditionWait(
Tcl_Condition *condPtr, /* Really (WinCondition **) */
Tcl_Mutex *mutexPtr, /* Really (CRITICAL_SECTION **) */
const Tcl_Time *timePtr) /* Timeout on waiting period */
{
WinCondition *winCondPtr; /* Per-condition queue head */
CRITICAL_SECTION *csPtr; /* Caller's Mutex, after casting */
DWORD wtime; /* Windows time value */
int timeout; /* True if we got a timeout */
int doExit = 0; /* True if we need to do exit setup */
ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
/*
* Self initialize the two parts of the condition. The per-condition and
* per-thread parts need to be handled independently.
*/
if (tsdPtr->flags == WIN_THREAD_UNINIT) {
TclpMasterLock();
/*
* Create the per-thread event and queue pointers.
*/
if (tsdPtr->flags == WIN_THREAD_UNINIT) {
tsdPtr->condEvent = CreateEvent(NULL, TRUE /* manual reset */,
FALSE /* non signaled */, NULL);
tsdPtr->nextPtr = NULL;
tsdPtr->prevPtr = NULL;
tsdPtr->flags = WIN_THREAD_RUNNING;
doExit = 1;
}
TclpMasterUnlock();
if (doExit) {
/*
* Create a per-thread exit handler to clean up the condEvent. We
* must be careful to do this outside the Master Lock because
* Tcl_CreateThreadExitHandler uses its own ThreadSpecificData,
* and initializing that may drop back into the Master Lock.
*/
Tcl_CreateThreadExitHandler(FinalizeConditionEvent, tsdPtr);
}
}
if (*condPtr == NULL) {
TclpMasterLock();
/*
* Initialize the per-condition queue pointers and Mutex.
*/
if (*condPtr == NULL) {
winCondPtr = ckalloc(sizeof(WinCondition));
InitializeCriticalSection(&winCondPtr->condLock);
winCondPtr->firstPtr = NULL;
winCondPtr->lastPtr = NULL;
*condPtr = (Tcl_Condition) winCondPtr;
TclRememberCondition(condPtr);
}
TclpMasterUnlock();
}
csPtr = *((CRITICAL_SECTION **)mutexPtr);
winCondPtr = *((WinCondition **)condPtr);
if (timePtr == NULL) {
wtime = INFINITE;
} else {
wtime = timePtr->sec * 1000 + timePtr->usec / 1000;
}
/*
* Queue the thread on the condition, using the per-condition lock for
* serialization.
*/
tsdPtr->flags = WIN_THREAD_BLOCKED;
tsdPtr->nextPtr = NULL;
EnterCriticalSection(&winCondPtr->condLock);
tsdPtr->prevPtr = winCondPtr->lastPtr; /* A: */
winCondPtr->lastPtr = tsdPtr;
if (tsdPtr->prevPtr != NULL) {
tsdPtr->prevPtr->nextPtr = tsdPtr;
}
if (winCondPtr->firstPtr == NULL) {
winCondPtr->firstPtr = tsdPtr;
}
/*
* Unlock the caller's mutex and wait for the condition, or a timeout.
* There is a minor issue here in that we don't count down the timeout if
* we get notified, but another thread grabs the condition before we do.
* In that race condition we'll wait again for the full timeout. Timed
* waits are dubious anyway. Either you have the locking protocol wrong
* and are masking a deadlock, or you are using conditions to pause your
* thread.
*/
LeaveCriticalSection(csPtr);
timeout = 0;
while (!timeout && (tsdPtr->flags & WIN_THREAD_BLOCKED)) {
ResetEvent(tsdPtr->condEvent);
LeaveCriticalSection(&winCondPtr->condLock);
if (WaitForSingleObjectEx(tsdPtr->condEvent, wtime,
TRUE) == WAIT_TIMEOUT) {
timeout = 1;
}
EnterCriticalSection(&winCondPtr->condLock);
}
/*
* Be careful on timeouts because the signal might arrive right around the
* time limit and someone else could have taken us off the queue.
*/
if (timeout) {
if (tsdPtr->flags & WIN_THREAD_RUNNING) {
timeout = 0;
} else {
/*
* When dequeuing, we can leave the tsdPtr->nextPtr and
* tsdPtr->prevPtr with dangling pointers because they are
* reinitialilzed w/out reading them when the thread is enqueued
* later.
*/
if (winCondPtr->firstPtr == tsdPtr) {
winCondPtr->firstPtr = tsdPtr->nextPtr;
} else {
tsdPtr->prevPtr->nextPtr = tsdPtr->nextPtr;
}
if (winCondPtr->lastPtr == tsdPtr) {
winCondPtr->lastPtr = tsdPtr->prevPtr;
} else {
tsdPtr->nextPtr->prevPtr = tsdPtr->prevPtr;
}
tsdPtr->flags = WIN_THREAD_RUNNING;
}
}
LeaveCriticalSection(&winCondPtr->condLock);
EnterCriticalSection(csPtr);
}