/*++

Copyright (c) 1995-1996 Microsoft Corporation

Module Name:

    Worker.cxx

Abstract:

    Backgroup activies releated to running down and cleaning up OR and pinging
    remote OR's are handled here.

Author:

    Mario Goertzel    [MarioGo]

Revision History:

    MarioGo     03-02-95    Bits 'n pieces
    MarioGo     01-18-96    Locally unique IDs

--*/

#include <or.hxx>

static CInterlockedInteger cTaskThreads(0);

#if DBG_DETAIL
extern "C" void printf(char *, ...);
#endif

#define TASKTHREAD_STACK_PAGES  3

#define SECS_BETWEEN_FLUSHES 30

typedef enum {  PWR_SUSPENDED, PWR_RUNNING } PWR_STATE;

PWR_STATE gPowerState = PWR_RUNNING;

void OLESCMBindingHandleFlush();

#if _MSC_FULL_VER >= 13008827
#pragma warning(push)
#pragma warning(disable:4715)			// Not all control paths return (due to infinite loop)
#endif

DWORD WINAPI
ObjectExporterWorkerThread(LPVOID /* ignored */)
/*++

Routine Description:

    Main background thread for the object resolver.  This thread
    manages a number of background tasks:
        Cleaning up the client oxid cache.
        Running down un-pinged sets.
        Starting task threads to rundown server OIDs and ping sets.

    This thread must not block for a long time.  Task threads
    should be used for possibly blocking operations like remote
    pinging and rundown of OIDs.

Arguments:

    Ignored

Return Value:

    None - should never return.

--*/
{
    ORSTATUS status;
    CTime    now(0);
    CTime    timeout(0);
    CTime    delay(0);
    CTime    start(0);
    CTime    lastflush(0);
    BOOL     fCreateThread;
    SYSTEM_INFO si;

    // Retrieve system info so we can start task threads
    // with an appropriate initial stack size
    GetSystemInfo(&si);

    lastflush.SetNow();

    for(;;)
        {
        now.SetNow();
        delay = now;
        delay += BasePingInterval;

        // Cleanup old sets.
        //
        // Sets are usually cleaned up during processing of pings.  (As one set is
        // pinged, the next set will be checked to see if it needs to be rundown.)
        //
        // If there's exactly one set in the table, then it won't be run down except
        // by this thread.
        //
        // NOTE: Similar code in _SimplePing().

        gpServerLock->LockShared();

        ID setid = gpServerSetTable->CheckForRundowns();
        if (setid)
        {
            gpServerLock->ConvertToExclusive();

            if (gpServerSetTable->RundownSetIfNeeded(setid))
            {
                delay.SetNow();
            }

            gpServerLock->UnlockExclusive();
        }
        else
        {
            gpServerLock->UnlockShared();
        }

        //
        // Cleanup old Client OXIDs
        //
        if (gpClientOxidPList->PeekMin(timeout))
        {
            if (timeout < now)
            {
                CClientOxid *pOxid;
                CListElement *ple;

                gpClientLock->LockExclusive();

                while (ple = gpClientOxidPList->MaybeRemoveMin(now))
                {
                    pOxid = CClientOxid::ContainingRecord(ple);
                    delete pOxid;
                }
                gpClientLock->UnlockExclusive();

                delay.SetNow();
            }
            else
            {
                if (delay > timeout)
                {
                    delay = timeout;
                }
            }
        }

        //
        // Make sure pinging and rundowns are proceding
        //
        fCreateThread = FALSE;

        // We want to create an extra task thread if we've fallen
        // behind on pings.  As more threads are created the
        // requirements for "behind" become harder to meet.
        if (gpClientSetPList->PeekMin(timeout))
        {
            start = now;
            start += (BasePingInterval + 10*cTaskThreads);

            if (cTaskThreads == 0 || start < timeout)
            {
                fCreateThread = TRUE;
            }
            else
            {
                if (delay > start)
                {
                    delay = start;
                }
            }
        }

        // We want to create an extra task thread if we've fallen
        // behind in running down local objects.  As more threads are
        // created the requirements for "behind" become harder to meet.
        if (gpServerOidPList->PeekMin(timeout))
        {
            start = now;
            start -= 10*cTaskThreads;
            if (timeout < start)
            {
                fCreateThread = TRUE;
            }
            else
            {
                start = timeout;
                start += 2*10*cTaskThreads;
                if (delay > start)
                {
                    delay = start;
                }
            }
        }

        if (fCreateThread)
        {
            KdPrintEx((DPFLTR_DCOMSS_ID,
                       DPFLTR_INFO_LEVEL,
                       "OR: Creating additional task thread, we're behind..\n"));

            cTaskThreads++;

            DWORD tid;
            HANDLE hThread =  CreateThread(0,
                                           (si.dwPageSize * TASKTHREAD_STACK_PAGES),
                                           ObjectExporterTaskThread,
                                           0,
                                           0,
                                           &tid
                                           );
            if (0 != hThread)
            {
                CloseHandle(hThread);
            }
            else
            {
                cTaskThreads--;
            }
        }

#if DBG_DETAIL
        printf("================================================================\n"
               "ServerOxids: %d, ServerOids: %d, ServerSets: %d\n"
               "ClientOxids: %d, ClientOids: %d, ClientSets: %d\n"
               "Mids: %d, Processes %d, worker threads: %d\n"
               "Sleeping for %d seconds...\n",
               gpServerOxidTable->Size(),
               gpServerOidTable->Size(),
               gpServerSetTable->Size(),
               gpClientOxidTable->Size(),
               gpClientOidTable->Size(),
               gpClientSetTable->Size(),
               gpMidTable->Size(),
               gpProcessList->Size(),
               cTaskThreads,
               delay - now + 1
               );
#endif

        delay += 1;

        if (delay - lastflush > SECS_BETWEEN_FLUSHES)
        {       
            // Give olescm a chance to do other work
            OLESCMBindingHandleFlush();
            
            lastflush.SetNow();
        }

        delay.Sleep();
    }

   return(0);
}

#if _MSC_FULL_VER >= 13008827
#pragma warning(pop)
#endif


void 
NotifyCOMOnSuspend()
/*++

Routine Desciption

    Resets state and takes appropriate action when the machine
    goes into a standby (or, hibernate) state.

Arguments:

    none

Return Value:

    void

--*/
{
    ASSERT(gPowerState == PWR_RUNNING);

    // Just set the flag.  This will block any further
    // rundowns from happening from now until we get a
    // resume notification.
    gPowerState = PWR_SUSPENDED;

    return;
}


void 
NotifyCOMOnResume()
/*++

Routine Desciption

    Resets state and takes appropriate action when the machine
    starts running again after being in the standby/hibernate
    state.

Arguments:

    none

Return Value:

    void

--*/
{
    // We cannot assert here that we're suspended, since the machine
    // can suspend in critical situations w/o notifying us

    //
    // First reset all of the server pingset timers.
    //
    gpServerLock->LockExclusive();

    // After a resume, all ping sets get reset to zero
    gpServerSetTable->PingAllSets();

    gpServerLock->UnlockExclusive();

    //
    // Second and last, reset the power state so that future
    // rundowns will not be blocked.
    //
    gPowerState = PWR_RUNNING;

    return;
}



DWORD WINAPI
ObjectExporterTaskThread(LPVOID /* ignored */)
{
    CTime          now(0);
    CTime          delay(0);
    CTime          timeout(0);
    ORSTATUS       status;
    CListElement  *ple;
    CClientSet    *pSet;
    CServerOid    *pOid;

    enum {
         Idle,     // No work to do at all.
         Waiting,  // No work to do yet.
         Busy      // Did work this iteration.
         }     eState;

    for(;;)
	{
        now.SetNow();
        delay = now;
        delay += BasePingInterval;
        eState = Idle;

        // Ping remote sets.

        if (gpClientSetPList->PeekMin(timeout))
        {
            eState = Waiting;

            if (now >= timeout)
            {
                eState = Busy;

                ple = gpClientSetPList->MaybeRemoveMin(now);

                if (ple)
                {
                    // Actually ping the set

                    pSet = CClientSet::ContainingRecord(ple);

                    pSet->PingServer();

                    // Set maybe invalid now.
                }
            }
            else
            {
                // Not ready to ping yet.
                delay = timeout;
            }
        }

        //
        // Process server OID rundowns.  Only do this
        // if there's something to rundown, and the machine 
        // is not in the suspended state.
        //
        if (gPowerState == PWR_RUNNING &&
            gpServerOidPList->PeekMin(timeout))
        {
            if (eState == Idle)
                eState = Waiting;

            if (now >= timeout)
            {
                eState = Busy;

                gpServerLock->LockExclusive();

                CServerOid* apOid[MAX_OID_RUNDOWNS_PER_CALL];
                ULONG       cOids;

                ple = gpServerOidPList->MaybeRemoveMin(now);
				pOid = CServerOid::ContainingRecord(ple);

                if (ple && pOid->IsRunningDown() == FALSE)
                {
                    apOid[0] = pOid;
                    cOids = 1;
                    ASSERT(pOid->IsFreed() == FALSE);
                    ASSERT(pOid->IsPinned() == FALSE);
                    pOid->SetRundown(TRUE);

                    while(cOids < MAX_OID_RUNDOWNS_PER_CALL && pOid)
                    {
                        pOid = gpServerOidPList->MaybeRemoveMatchingOxid(now, apOid[0]);

                        if (pOid && pOid->IsRunningDown() == FALSE)
                        {
                            ASSERT(pOid->IsFreed() == FALSE);
                            ASSERT(pOid->IsPinned() == FALSE);
                            pOid->SetRundown(TRUE);
                            apOid[cOids] = pOid;
                            cOids++;
                        }
                    }

                    ASSERT(cOids < MAX_OID_RUNDOWNS_PER_CALL+1 && cOids >= 1);
                    ASSERT(apOid[0]->GetOxid() == apOid[cOids - 1]->GetOxid());
                
                    // Note: This call will unlock the server lock. While 
                    // this happens the oids maybe added, deleted, added
                    // and deleted, added and rundown from one or more sets.

                    CServerOxid* pOxid = apOid[0]->GetOxid();
                    pOxid->RundownOids(cOids, apOid);

                    // Assert RundownOids released the lock
                    ASSERT(!gpServerLock->HeldExclusive());                 
                }
                else
                {
                    gpServerLock->UnlockExclusive();
                }
            }
            else
            {
                // Not ready to rundown yet.
                if (delay > timeout)
                {
                    delay = timeout;
                }
            }
        }

        // Decide if this task thread should exit or sleep and loop.
        ASSERT(eState == Idle || eState == Busy || eState == Waiting);

        if ((eState == Idle) || (eState == Waiting && cTaskThreads > 2))
        {
            // No work or we're all caught up and have extra threads.
            cTaskThreads--;
            return(0);
        }
        else
        {
            if (eState == Waiting)
            {
                // Sleep until just after the next work item is ready.
                delay += 1;
                delay.Sleep();
            }
        }
    }

    return(0);
}