void TaskThread::Entry()
{
Task* theTask = NULL;
while (true)
{
theTask = this->WaitForTask();
//
// WaitForTask returns NULL when it is time to quit
if (theTask == NULL || false == theTask->Valid())
return;
Bool16 doneProcessingEvent = false;
while (!doneProcessingEvent)
{
//If a task holds locks when it returns from its Run function,
//that would be catastrophic and certainly lead to a deadlock
#if DEBUG
Assert(this->GetNumLocksHeld() == 0);
Assert(theTask->fInRunCount == 0);
theTask->fInRunCount++;
#endif
theTask->fUseThisThread = NULL; // Each invocation of Run must independently
// request a specific thread.
SInt64 theTimeout = 0;
if (theTask->fWriteLock)
{
OSMutexWriteLocker mutexLocker(&TaskThreadPool::sMutexRW);
if (TASK_DEBUG) qtss_printf("TaskThread::Entry run global locked TaskName=%s CurMSec=%.3f thread=%p task=%p\n", theTask->fTaskName, OS::StartTimeMilli_Float(), (void *) this, (void *)theTask);
theTimeout = theTask->Run();
theTask->fWriteLock = false;
}
else
{
OSMutexReadLocker mutexLocker(&TaskThreadPool::sMutexRW);
if (TASK_DEBUG) qtss_printf("TaskThread::Entry run TaskName=%s CurMSec=%.3f thread=%p task=%p\n", theTask->fTaskName, OS::StartTimeMilli_Float(), (void *) this, (void *)theTask);
theTimeout = theTask->Run();
}
#if DEBUG
Assert(this->GetNumLocksHeld() == 0);
theTask->fInRunCount--;
Assert(theTask->fInRunCount == 0);
#endif
if (theTimeout < 0)
{
if (TASK_DEBUG)
{
qtss_printf("TaskThread::Entry delete TaskName=%s CurMSec=%.3f thread=%p task=%p\n", theTask->fTaskName, OS::StartTimeMilli_Float(), (void *) this, (void *)theTask);
theTask->fUseThisThread = NULL;
if (NULL != fHeap.Remove(&theTask->fTimerHeapElem))
qtss_printf("TaskThread::Entry task still in heap before delete\n");
if (NULL != theTask->fTaskQueueElem.InQueue())
qtss_printf("TaskThread::Entry task still in queue before delete\n");
theTask->fTaskQueueElem.Remove();
if (theTask->fEvents &~Task::kAlive)
qtss_printf("TaskThread::Entry flags still set before delete\n");
(void)atomic_sub(&theTask->fEvents, 0);
::strncat(theTask->fTaskName, " deleted", sizeof(theTask->fTaskName) - 1);
}
theTask->fTaskName[0] = 'D'; //mark as dead
delete theTask;
theTask = NULL;
doneProcessingEvent = true;
}
else if (theTimeout == 0)
{
//We want to make sure that 100% definitely the task's Run function WILL
//be invoked when another thread calls Signal. We also want to make sure
//that if an event sneaks in right as the task is returning from Run()
//(via Signal) that the Run function will be invoked again.
doneProcessingEvent = compare_and_store(Task::kAlive, 0, &theTask->fEvents);
if (doneProcessingEvent)
theTask = NULL;
}
else
{
//note that if we get here, we don't reset theTask, so it will get passed into
//WaitForTask
if (TASK_DEBUG) qtss_printf("TaskThread::Entry insert TaskName=%s in timer heap thread=%p elem=%p task=%p timeout=%.2f\n", theTask->fTaskName, (void *) this, (void *)&theTask->fTimerHeapElem, (void *)theTask, (float)theTimeout / (float)1000);
theTask->fTimerHeapElem.SetValue(OS::Milliseconds() + theTimeout);
fHeap.Insert(&theTask->fTimerHeapElem);
(void)atomic_or(&theTask->fEvents, Task::kIdleEvent);
doneProcessingEvent = true;
}
#if TASK_DEBUG
SInt64 yieldStart = OS::Milliseconds();
#endif
this->ThreadYield();
#if TASK_DEBUG
SInt64 yieldDur = OS::Milliseconds() - yieldStart;
static SInt64 numZeroYields;
if (yieldDur > 1)
{
if (TASK_DEBUG) qtss_printf("TaskThread::Entry time in Yield %qd, numZeroYields %qd \n", yieldDur, numZeroYields);
numZeroYields = 0;
}
else
numZeroYields++;
#endif
}
}
}
void EventContext::RequestEvent(int theMask)
{
#if DEBUG
fModwatched = true;
#endif
//
// The first time this function gets called, we're supposed to
// call watchevent. Each subsequent time, call modwatch. That's
// the way the MacOS X event queue works.
if (fWatchEventCalled)
{
fEventReq.er_eventbits = theMask;
#if MACOSXEVENTQUEUE
if (modwatch(&fEventReq, theMask) != 0)
#else
if (select_modwatch(&fEventReq, theMask) != 0)
#endif
AssertV(false, OSThread::GetErrno());
}
else
{
//allocate a Unique ID for this socket, and add it to the ref table
#ifdef __Win32__
//
// Kind of a hack. On Win32, the way that we pass around the unique ID is
// by making it the message ID of our Win32 message (see win32ev.cpp).
// Messages must be >= WM_USER. Hence this code to restrict the numberspace
// of our UniqueIDs.
if (!compare_and_store(8192, WM_USER, &sUniqueID)) // Fix 2466667: message IDs above a
fUniqueID = (PointerSizedInt)atomic_add(&sUniqueID, 1); // level are ignored, so wrap at 8192
else
fUniqueID = (PointerSizedInt)WM_USER;
#else
if (!compare_and_store(10000000, 1, &sUniqueID))
fUniqueID = (PointerSizedInt)atomic_add(&sUniqueID, 1);
else
fUniqueID = 1;
#endif
fRef.Set(fUniqueIDStr, this);
Assert(fEventThread->fRefTable.Register(&fRef) == OS_NoErr);
//fill out the eventreq data structure
::memset( &fEventReq, '\0', sizeof(fEventReq));
fEventReq.er_type = EV_FD;
fEventReq.er_handle = fFileDesc;
fEventReq.er_eventbits = theMask;
fEventReq.er_data = (void*)fUniqueID;
fWatchEventCalled = true;
#if MACOSXEVENTQUEUE
if (watchevent(&fEventReq, theMask) != 0)
#else
if (select_watchevent(&fEventReq, theMask) != 0)
#endif
//this should never fail, but if it does, cleanup.
AssertV(false, OSThread::GetErrno());
}
}