/*****************************************************************************\ * MODULE: cachemgr.cxx * * The module contains routines to implement the caching algorithm for * the printers provider * * Purpose: * * Description: * * The Caching algorithm operates based on a state machine. There are five * states in the cache: * * CACHE_STATE_INIT * CACHE_STATE_ACCESSED_VALID, * CACHE_STATE_DATA_VALID, * CACHE_STATE_ACCESSED_VALID_AGAIN, * CACHE_STATE_NOT_ACCESSED_VALID_AGAIN * * CACHE_STATE_INIT is the initial state. Once the first cache hit * comes in, the cahce manager calles FetchData to fetch the data * and goes into CACHE_STATE_ACCESSED_VALID state. * * In CACHE_STATE_ACCESSED_VALID state, the cache manager waits * for the minimum cache timeout and go to CACHE_STATE_DATA_VALID * * In CACHE_STATE_DATA_VALID state, the cache manager waits for * another cache hit withing half of the last fetch time. * * If there is a hit during this waiting, the cache manager will go * for another fetch and go to CACHE_STATE_ACCESSED_VALID state. * * If there is no hit during the waiting period, the cache manager * waits for another timeout or another cache hit. * * If there is no access during the waiting, the cache manager * invalidates the cache. Otherwise, the cache manager go out and * do anther data fetch and then go to CACHE_STATE_ACCESSED_VALID. * * * * Copyright (C) 1998-1999 Microsoft Corporation * * History: * 10/16/98 weihaic Created * \*****************************************************************************/ #include "precomp.h" #include "priv.h" extern BOOL _ppinfo_net_get_info( IN PCINETMONPORT pIniPort, OUT PPRINTER_INFO_2 *ppInfo, OUT LPDWORD lpBufAllocated, IN ALLOCATORFN pAllocator); extern BOOL ppjob_EnumForCache( IN PCINETMONPORT pIniPort, OUT LPPPJOB_ENUM *ppje); // cdwMaxCacheValidTime is the maximum expire time for the current cache // Idealy, we should put a large number to increase the effiency of the cache // so we choose 30 seconds (30*1000) as the final number. For testing purpose, // we put 15 seconds to increase the hit of the fetch data code // // weihaic 10/23/98 // const DWORD cdwMaxCacheValidTime = 30*1000; // The cache content will expire after 30 seconds. const DWORD cdwMinCacheValidTime = 2*1000; // The cache content will be valid for at least 2 seconds CacheMgr::CacheMgr (): m_dwState (CACHE_STATE_INIT), m_pIniPort (NULL), m_pData (NULL), m_hDataReadyEvent (NULL), m_hHitEvent (NULL), m_hInvalidateCacheEvent (NULL), m_hThread (NULL), m_bCacheStopped (FALSE), m_bAccessed (FALSE), m_bInvalidateFlag (FALSE), m_dwThreadRefCount (0), m_bValid (FALSE) { if ((m_hDataReadyEvent = CreateEvent (NULL, TRUE, FALSE, NULL)) && (m_hHitEvent = CreateEvent (NULL, FALSE, FALSE, NULL)) && (m_hInvalidateCacheEvent = CreateEvent (NULL, FALSE, FALSE, NULL)) ) m_bValid = TRUE; } CacheMgr::~CacheMgr () { } VOID CacheMgr::AttachThreadHandle ( HANDLE hThread ) { CacheData.Lock(); m_hThread = hThread; m_dwThreadRefCount = 1; DBGMSGT (DBG_CACHE_TRACE, ( TEXT ("AttachThreadHandle (hThread = %d)"), hThread)); CacheData.Unlock(); } HANDLE CacheMgr::GetThreadHandle ( VOID ) { HANDLE hThread; CacheData.Lock(); hThread = m_hThread; if (m_hThread) { m_dwThreadRefCount++; } DBGMSGT (DBG_CACHE_TRACE, ( TEXT ("GetThreadHandle (hThread = %d, Count = %d)"), hThread, m_dwThreadRefCount)); CacheData.Unlock(); return hThread; } VOID CacheMgr::ReleaseThreadHandle ( VOID ) { HANDLE hThread = NULL; CacheData.Lock(); if (m_hThread) { m_dwThreadRefCount--; DBGMSGT (DBG_CACHE_TRACE, ( TEXT ("ReleaseThreadHandle (hThread = %d, Count = %d)"), hThread, m_dwThreadRefCount)); if (m_dwThreadRefCount == 0) { hThread = m_hThread; m_hThread = NULL; } } CacheData.Unlock(); if (hThread) { CloseHandle (hThread); } } VOID CacheMgr::Shutdown () { HANDLE hThread; CacheRead.Lock (); // No more read is possible m_bCacheStopped = TRUE; if (hThread = GetThreadHandle ()) { SetEvent (m_hInvalidateCacheEvent); // Wait for another thread to exit WaitForSingleObject (hThread, INFINITE); ReleaseThreadHandle (); } if (m_hDataReadyEvent) { CloseHandle (m_hDataReadyEvent); } if (m_hHitEvent) { CloseHandle (m_hHitEvent); } if (m_hInvalidateCacheEvent) { CloseHandle (m_hInvalidateCacheEvent); } m_bValid = FALSE; CacheRead.Unlock (); delete this; } BOOL CacheMgr::SetupAsyncFetch ( PCINETMONPORT pIniPort) { BOOL bRet = FALSE; PTHREADCONTEXT pThreadData = new THREADCONTEXT; HANDLE hThread = NULL; if (pThreadData) { pThreadData->pIniPort = pIniPort; pThreadData->pCache = this; pThreadData->pSidToken = new CSid; if (pThreadData->pSidToken && pThreadData->pSidToken->bValid()) { if (hThread = CreateThread (NULL, COMMITTED_STACK_SIZE, (LPTHREAD_START_ROUTINE)CacheMgr::WorkingThread, (PVOID) pThreadData, CREATE_SUSPENDED, NULL)) { bRet = TRUE; } } if (bRet) { AttachThreadHandle (hThread); // // The thread is created in the suspended state // if (ResumeThread (hThread) == -1) { // // Resume thread failed, so we need to clean up the thread handle // ReleaseThreadHandle (); bRet = FALSE; } } if (!bRet) { if (pThreadData->pSidToken) { delete pThreadData->pSidToken; } delete (pThreadData); } } return bRet; } VOID CacheMgr::TransitState ( PCINETMONPORT pIniPort) { PVOID pData = NULL; DWORD dwFetchTime = 0; CACHESTATE dwState, dwOldState; BOOL bNewData; HANDLE hHandles[2]; hHandles [0] = m_hHitEvent; hHandles [1] = m_hInvalidateCacheEvent; dwState = m_dwState; do { DBGMSGT (DBG_CACHE_TRACE, ( TEXT ("TransitState: current state %d"), m_dwState)); dwState = m_dwState; bNewData = FALSE; m_bAccessed = FALSE; switch (dwState) { case CACHE_STATE_INIT: // Clean the data ready event ResetEvent (m_hDataReadyEvent); if (GetFetchTime (pIniPort, &dwFetchTime, &pData)) { bNewData = TRUE; dwState = CACHE_STATE_ACCESSED_VALID; } else { //Invalid Cache Content DBGMSGT (DBG_CACHE_ERROR, ( TEXT ("TransitState: FatalError %d"), GetLastError)); // Invalidate the cache content, so that when the next get comes, it will // get the NULL pointer. pData = NULL; bNewData = TRUE; dwState = CACHE_STATE_ACCESSED_VALID; } break; case CACHE_STATE_ACCESSED_VALID: WaitForSingleObject (m_hInvalidateCacheEvent, cdwMinCacheValidTime); dwState = CACHE_STATE_DATA_VALID; break; case CACHE_STATE_DATA_VALID: WaitForSingleObject (m_hInvalidateCacheEvent, dwFetchTime / 2); if (m_bAccessed) { // The cache has been accessed during the waiting time dwState = CACHE_STATE_ACCESSED_VALID_AGAIN; } else { // The cache has not been accessed during the waiting time dwState = CACHE_STATE_NOT_ACCESSED_VALID_AGAIN; } break; case CACHE_STATE_ACCESSED_VALID_AGAIN: if (GetFetchTime (pIniPort, &dwFetchTime, &pData)) { bNewData = TRUE; dwState = CACHE_STATE_ACCESSED_VALID; } else { //Invalid Cache Content DBGMSGT (DBG_CACHE_ERROR, ( TEXT ("TransitState: FatalError %d"), GetLastError)); // Invalidate the cache content, so that when the next access to cache comes, // it will get a NULL pointer. pData = NULL; bNewData = TRUE; dwState = CACHE_STATE_ACCESSED_VALID; } break; case CACHE_STATE_NOT_ACCESSED_VALID_AGAIN: // This has to be a long wait so that the cache will be valid for an access long after // the last fetch happeen ResetEvent (m_hHitEvent); switch (WaitForMultipleObjects (2, hHandles, FALSE, cdwMaxCacheValidTime )) { case WAIT_TIMEOUT: dwState = CACHE_STATE_INIT; break; case WAIT_OBJECT_0: //Accessed if (GetFetchTime (pIniPort, &dwFetchTime, &pData)) { bNewData = TRUE; dwState = CACHE_STATE_ACCESSED_VALID; } else { //Invalid Cache Content DBGMSGT (DBG_CACHE_ERROR, ( TEXT ("TransitState: FatalError %d"), GetLastError)); // Invalidate the cache content, so that when the next access to cache comes, // it will get a NULL pointer. pData = NULL; bNewData = TRUE; dwState = CACHE_STATE_ACCESSED_VALID; } break; case WAIT_OBJECT_0 + 1: dwState = CACHE_STATE_INIT; break; default: // ERROR DBGMSGT (DBG_CACHE_ERROR, ( TEXT ("TransitState: WaitForSingleObject FatalError %d"), GetLastError)); // Invalidate the cache dwState = CACHE_STATE_INIT; break; } break; default: DBGMSGT (DBG_CACHE_ERROR, (TEXT ("AsyncFech: wrong state %d"), m_dwState)); // Invalidate the cache dwState = CACHE_STATE_INIT; } if (m_bCacheStopped) { // Cache is being stopped. Cleanup everything this thread generates if (bNewData) { FreeBuffer (pIniPort, pData); } // Since the caching thread is going to abort, so we need to raise // this flag so that the waiting thread can go on. SetEvent (m_hDataReadyEvent); break; } dwOldState = m_dwState; SetState (pIniPort, dwState, bNewData, pData); if (dwOldState == CACHE_STATE_INIT) { SetEvent (m_hDataReadyEvent); } if (m_bInvalidateFlag) { // Another thread called invalidate thread and hope get rid of the thread m_dwState = CACHE_STATE_INIT; } } while ( m_dwState != CACHE_STATE_INIT ); // Terminate the async fetch thread ReleaseThreadHandle (); DBGMSGT (DBG_CACHE_TRACE, (TEXT ("CacheMgr::TransitState: Async thread quit"))); return; } VOID CacheMgr::SetState ( PCINETMONPORT pIniPort, CACHESTATE dwState, BOOL bNewData, PVOID pNewData) { PVOID pOldData = NULL; m_bAccessed = 0; if (bNewData) { CacheData.Lock (); pOldData = m_pData; m_pData = pNewData; CacheData.Unlock (); } // This line must be here, since otherwise, the state is updated to the new one // but the data are not // m_dwState = dwState; if (pOldData) { FreeBuffer (pIniPort, pOldData); } } VOID CacheMgr::WorkingThread ( PTHREADCONTEXT pThreadData) { CacheMgr *pThis = pThreadData->pCache; PCINETMONPORT pIniPort = pThreadData->pIniPort; pThreadData->pSidToken->SetCurrentSid (); delete pThreadData->pSidToken; pThreadData->pSidToken = NULL; delete pThreadData; pThis->TransitState (pIniPort); } BOOL CacheMgr::GetFetchTime ( PCINETMONPORT pIniPort, LPDWORD pdwTime, PVOID *ppData) { BOOL bRet = FALSE; DWORD dwT0, dwT1; dwT0 = GetTickCount(); if (FetchData (pIniPort, ppData)) { bRet = TRUE; } dwT1 = GetTickCount(); *pdwTime = GetTimeDiff (dwT0, dwT1); DBGMSGT (DBG_CACHE_TRACE, (TEXT ("GetFetchTime: returns %d, timediff=%d ms"), bRet, GetTimeDiff (dwT0, dwT1))); return bRet; } PVOID CacheMgr::BeginReadCache ( PCINETMONPORT pIniPort) { HANDLE hThread = NULL; if (m_bValid) { CacheRead.Lock (); CUserData CurUser; while (TRUE) { if (m_dwState == CACHE_STATE_INIT) { m_CurUser = CurUser; hThread = GetThreadHandle (); if (!hThread) { // If there is no thread running, we need to reset the dataready event ResetEvent (m_hDataReadyEvent); } if (hThread // There is already a thread running || SetupAsyncFetch (pIniPort)) { // We must leave the critical section since it might take forever to // get the information at the first time CacheRead.Unlock (); WaitForSingleObject (m_hDataReadyEvent, INFINITE); CacheRead.Lock (); } if (hThread) { ReleaseThreadHandle (); } break; } else { if (m_CurUser == CurUser) { if (m_dwState == CACHE_STATE_NOT_ACCESSED_VALID_AGAIN) { SetEvent (m_hHitEvent); } break; } else { // We must call the internal version of InvalidateCache since // we have to leave the critical section when waiting for the termination // of the working thread. // _InvalidateCache (); // Now, the state becomes CACHE_STATE_INIT } } } m_bAccessed = TRUE; BOOL bRet = CacheData.Lock (); DBGMSGT (DBG_CACHE_TRACE, (TEXT ("CacheData.Lock() = %d"), bRet)); return m_pData; } else return NULL; } VOID CacheMgr::EndReadCache (VOID) { DBGMSGT (DBG_CACHE_TRACE, (TEXT ("CacheMgr::EndReadCache: Entered"))); if (m_bValid) { BOOL bRet = CacheData.Unlock (); DBGMSGT (DBG_CACHE_TRACE, (TEXT ("CacheData.Unlock() = %d"), bRet)); CacheRead.Unlock (); } } VOID CacheMgr::_InvalidateCache () { HANDLE hThread = NULL; if (!m_bInvalidateFlag) { m_bInvalidateFlag = TRUE; SetEvent (m_hInvalidateCacheEvent); } if (hThread = GetThreadHandle ()) { CacheRead.Unlock (); // We must leave the critical section since we don't know how long it will take for thread to exit // Wait for another thread to exit WaitForSingleObject (hThread, INFINITE); CacheRead.Lock (); ReleaseThreadHandle (); } // Clean up the event ResetEvent (m_hInvalidateCacheEvent); m_bInvalidateFlag = FALSE; DBGMSGT (DBG_CACHE_TRACE, ( TEXT ("CacheMgr::InvalidateCache dwState=%d"), m_dwState)); } VOID CacheMgr::InvalidateCache () { CacheRead.Lock (); _InvalidateCache (); CacheRead.Unlock (); } VOID CacheMgr::InvalidateCacheForUser( CLogonUserData *pUser ) /*++ Routine Description: This routine checks to see whether the given user is currently controlling the cache thread. If they are, the thread is terminated. Arguments: pUser - A pointer to the user. Return Value: None. --*/ { CacheRead.Lock(); if (m_CurUser == *(CUserData *)pUser) // Comparison is valid after caste _InvalidateCache (); CacheRead.Unlock(); } inline DWORD CacheMgr::GetTimeDiff ( DWORD t0, DWORD t1) { if (t1 > t0) { return t1 - t0; } else { return DWORD(-1) - t0 + t1; } } LPVOID CacheMgr::Allocator( DWORD cb) { return new CHAR[cb]; } GetPrinterCache::GetPrinterCache( PCINETMONPORT pIniPort): m_pIniPort (pIniPort) { } GetPrinterCache::~GetPrinterCache ( VOID) { if (m_pData) { FreeBuffer (m_pIniPort, m_pData); } } BOOL GetPrinterCache::FetchData ( PCINETMONPORT pIniPort, PVOID *ppData) { BOOL bRet = FALSE; PGETPRINTER_CACHEDATA pCacheData = NULL; DBGMSGT (DBG_CACHE_TRACE, (TEXT ("GetPrinterCache::FetchData begins"))); #ifdef DEBUG if (0) { // Simulate the hanging of the current thread // For debugging purpose. MessageBox (NULL, TEXT ("GetPrinterCache::FetchData called. Press OK to continue."), TEXT ("ALERT"), MB_OK); } #endif if (pCacheData = new GETPRINTER_CACHEDATA) { semEnterCrit (); pCacheData->bRet = _ppinfo_net_get_info(pIniPort, & (pCacheData->pInfo) , & (pCacheData->cbSize), Allocator); semLeaveCrit (); pCacheData->dwLastError = GetLastError (); DBGMSGT (DBG_CACHE_TRACE, (TEXT ("GetPrinterCache::FetchData bRet=%d, err=%d\n"), pCacheData->bRet, pCacheData->dwLastError )); // // We must return TRUE, otherwise PPGetPrinter won't get the correct last error // bRet = TRUE; //pCacheData->cbSize != 0; } if (!bRet) { DBGMSGT (DBG_CACHE_TRACE, (TEXT ("GetPrinterCache::FetchData failed, call FreeBuffer (%x, %x)"), pIniPort, pCacheData)); FreeBuffer (pIniPort, pCacheData); } else { *ppData = pCacheData; } return bRet; } BOOL GetPrinterCache::FreeBuffer ( PCINETMONPORT pIniPort, PVOID pData) { PGETPRINTER_CACHEDATA pCacheData = (PGETPRINTER_CACHEDATA) pData; DBGMSGT (DBG_CACHE_TRACE, (TEXT ("FreeBuffer(%x, %x) called"), pIniPort, pCacheData)); if (pCacheData) { if (pCacheData->pInfo) { delete [] (PCHAR)(pCacheData->pInfo); } delete pCacheData; } return TRUE; } BOOL GetPrinterCache::BeginReadCache ( PPRINTER_INFO_2 *ppInfo) { BOOL bRet = FALSE; if (m_bValid) { DBGMSGT (DBG_CACHE_TRACE, (TEXT ("GetPrinterCache::BeginReadCache: Entered"))); PGETPRINTER_CACHEDATA pData = (PGETPRINTER_CACHEDATA) CacheMgr::BeginReadCache (m_pIniPort); if (pData) { if (pData->bRet) { *ppInfo = pData->pInfo; bRet = TRUE; } else { SetLastError (pData->dwLastError); } } if (!bRet && GetLastError () == ERROR_SUCCESS) { SetLastError (ERROR_CAN_NOT_COMPLETE); } DBGMSGT (DBG_CACHE_TRACE, (TEXT ("GetPrinterCache::BeginReadCache: pData = %x, return = %d, lasterror = %d"), pData, bRet, GetLastError ())); } else { SetLastError (ERROR_CAN_NOT_COMPLETE); } return bRet; } EnumJobsCache::EnumJobsCache( PCINETMONPORT pIniPort): m_pIniPort (pIniPort) { } EnumJobsCache::~EnumJobsCache ( VOID) { if (m_pData) { FreeBuffer (m_pIniPort, m_pData); } } BOOL EnumJobsCache::FetchData ( PCINETMONPORT pIniPort, PVOID *ppData) { BOOL bRet = FALSE; HANDLE hPort = (HANDLE)pIniPort; PENUMJOBS_CACHEDATA pCacheData = NULL; DBGMSGT (DBG_CACHE_TRACE, (TEXT ("EnumJobsCache::FetchData begins"))); if (pCacheData = new ENUMJOBS_CACHEDATA) { pCacheData->pje = NULL; semEnterCrit (); pCacheData->bRet = ppjob_EnumForCache(pIniPort, & (pCacheData->pje)); pCacheData->dwLastError = GetLastError (); DBGMSGT (DBG_CACHE_TRACE, (TEXT ("EnumJobsCache::FetchData bRet=%d, err=%d\n"), pCacheData->bRet, pCacheData->dwLastError )); if (pCacheData->bRet) { if (pCacheData->pje) { pCacheData->cbSize = pCacheData->pje->cbSize; } else { pCacheData->cbSize = 0; } } semLeaveCrit (); bRet = TRUE; } if (bRet) { *ppData = pCacheData; } return bRet; } BOOL EnumJobsCache::FreeBuffer ( PCINETMONPORT pIniPort, PVOID pData) { PENUMJOBS_CACHEDATA pCacheData = (PENUMJOBS_CACHEDATA) pData; if (pCacheData) { if (pCacheData->pje) { // memFree has access to the global link list, so it is neccesary // to run it under critical secion. // semEnterCrit (); memFree(pCacheData->pje, memGetSize(pCacheData->pje)); semLeaveCrit (); } delete pCacheData; } return TRUE; } BOOL EnumJobsCache::BeginReadCache ( LPPPJOB_ENUM *ppje) { BOOL bRet = FALSE; if (m_bValid) { DBGMSGT (DBG_CACHE_TRACE, (TEXT ("EnumJobsCache::BeginReadCache: Entered"))); PENUMJOBS_CACHEDATA pData = (PENUMJOBS_CACHEDATA) CacheMgr::BeginReadCache (m_pIniPort); if (pData) { if (pData->bRet) { *ppje = pData->pje; bRet = TRUE; } else { SetLastError (pData->dwLastError); } } if (!bRet && GetLastError () == ERROR_SUCCESS) { SetLastError (ERROR_CAN_NOT_COMPLETE); } DBGMSGT (DBG_CACHE_TRACE, (TEXT ("EnumJobsCache::BeginReadCache: pData = %x, return = %d, lasterror = %d"), pData, bRet, GetLastError ())); } else { SetLastError (ERROR_CAN_NOT_COMPLETE); } return bRet; } VOID EnumJobsCache::EndReadCache ( VOID) { DBGMSGT (DBG_CACHE_TRACE, (TEXT ("EnumJobsCache::EndReadCache: Entered"))); CacheMgr::EndReadCache (); } /********************************************************************************* ** End of File (cachemgr.cxx) *********************************************************************************/