/* * tclWinNotify.c -- * * This file contains Windows-specific procedures for the notifier, * which is the lowest-level part of the Tcl event loop. This file * works together with ../generic/tclNotify.c. * * Copyright (c) 1995-1997 Sun Microsystems, Inc. * * See the file "license.terms" for information on usage and redistribution * of this file, and for a DISCLAIMER OF ALL WARRANTIES. * * RCS: @(#) $Id: tclWinNotify.c,v 1.14 2004/03/03 10:44:41 davygrvy Exp $ */ #include "tclWinInt.h" /* * The follwing static indicates whether this module has been initialized. */ #define INTERVAL_TIMER 1 /* Handle of interval timer. */ #define WM_WAKEUP WM_USER /* Message that is send by * Tcl_AlertNotifier. */ /* * The following static structure contains the state information for the * Windows implementation of the Tcl notifier. One of these structures * is created for each thread that is using the notifier. */ typedef struct ThreadSpecificData { CRITICAL_SECTION crit; /* Monitor for this notifier. */ DWORD thread; /* Identifier for thread associated with this * notifier. */ HANDLE event; /* Event object used to wake up the notifier * thread. */ int pending; /* Alert message pending, this field is * locked by the notifierMutex. */ HWND hwnd; /* Messaging window. */ int timeout; /* Current timeout value. */ int timerActive; /* 1 if interval timer is running. */ } ThreadSpecificData; static Tcl_ThreadDataKey dataKey; extern TclStubs tclStubs; extern Tcl_NotifierProcs tclOriginalNotifier; /* * The following static indicates the number of threads that have * initialized notifiers. It controls the lifetime of the TclNotifier * window class. * * You must hold the notifierMutex lock before accessing this variable. */ static int notifierCount = 0; TCL_DECLARE_MUTEX(notifierMutex) /* * Static routines defined in this file. */ static LRESULT CALLBACK NotifierProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam); /* *---------------------------------------------------------------------- * * Tcl_InitNotifier -- * * Initializes the platform specific notifier state. * * Results: * Returns a handle to the notifier state for this thread.. * * Side effects: * None. * *---------------------------------------------------------------------- */ ClientData Tcl_InitNotifier() { ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); WNDCLASS class; /* * Register Notifier window class if this is the first thread to * use this module. */ Tcl_MutexLock(¬ifierMutex); if (notifierCount == 0) { class.style = 0; class.cbClsExtra = 0; class.cbWndExtra = 0; class.hInstance = TclWinGetTclInstance(); class.hbrBackground = NULL; class.lpszMenuName = NULL; class.lpszClassName = "TclNotifier"; class.lpfnWndProc = NotifierProc; class.hIcon = NULL; class.hCursor = NULL; if (!RegisterClassA(&class)) { Tcl_Panic("Unable to register TclNotifier window class"); } } notifierCount++; Tcl_MutexUnlock(¬ifierMutex); tsdPtr->pending = 0; tsdPtr->timerActive = 0; InitializeCriticalSection(&tsdPtr->crit); tsdPtr->hwnd = NULL; tsdPtr->thread = GetCurrentThreadId(); tsdPtr->event = CreateEvent(NULL, TRUE /* manual */, FALSE /* !signaled */, NULL); return (ClientData) tsdPtr; } /* *---------------------------------------------------------------------- * * Tcl_FinalizeNotifier -- * * This function is called to cleanup the notifier state before * a thread is terminated. * * Results: * None. * * Side effects: * May dispose of the notifier window and class. * *---------------------------------------------------------------------- */ void Tcl_FinalizeNotifier(clientData) ClientData clientData; /* Pointer to notifier data. */ { ThreadSpecificData *tsdPtr = (ThreadSpecificData *) clientData; /* * Only finalize the notifier if a notifier was installed in the * current thread; there is a route in which this is not * guaranteed to be true (when tclWin32Dll.c:DllMain() is called * with the flag DLL_PROCESS_DETACH by the OS, which could be * doing so from a thread that's never previously been involved * with Tcl, e.g. the task manager) so this check is important. * * Fixes Bug #217982 reported by Hugh Vu and Gene Leache. */ if (tsdPtr == NULL) { return; } DeleteCriticalSection(&tsdPtr->crit); CloseHandle(tsdPtr->event); /* * Clean up the timer and messaging window for this thread. */ if (tsdPtr->hwnd) { KillTimer(tsdPtr->hwnd, INTERVAL_TIMER); DestroyWindow(tsdPtr->hwnd); } /* * If this is the last thread to use the notifier, unregister * the notifier window class. */ Tcl_MutexLock(¬ifierMutex); notifierCount--; if (notifierCount == 0) { UnregisterClassA("TclNotifier", TclWinGetTclInstance()); } Tcl_MutexUnlock(¬ifierMutex); } /* *---------------------------------------------------------------------- * * Tcl_AlertNotifier -- * * Wake up the specified notifier from any thread. This routine * is called by the platform independent notifier code whenever * the Tcl_ThreadAlert routine is called. This routine is * guaranteed not to be called on a given notifier after * Tcl_FinalizeNotifier is called for that notifier. This routine * is typically called from a thread other than the notifier's * thread. * * Results: * None. * * Side effects: * Sends a message to the messaging window for the notifier * if there isn't already one pending. * *---------------------------------------------------------------------- */ void Tcl_AlertNotifier(clientData) ClientData clientData; /* Pointer to thread data. */ { ThreadSpecificData *tsdPtr = (ThreadSpecificData *) clientData; /* * Note that we do not need to lock around access to the hwnd * because the race condition has no effect since any race condition * implies that the notifier thread is already awake. */ if (tsdPtr->hwnd) { /* * We do need to lock around access to the pending flag. */ EnterCriticalSection(&tsdPtr->crit); if (!tsdPtr->pending) { PostMessage(tsdPtr->hwnd, WM_WAKEUP, 0, 0); } tsdPtr->pending = 1; LeaveCriticalSection(&tsdPtr->crit); } else { SetEvent(tsdPtr->event); } } /* *---------------------------------------------------------------------- * * Tcl_SetTimer -- * * This procedure sets the current notifier timer value. The * notifier will ensure that Tcl_ServiceAll() is called after * the specified interval, even if no events have occurred. * * Results: * None. * * Side effects: * Replaces any previous timer. * *---------------------------------------------------------------------- */ void Tcl_SetTimer( Tcl_Time *timePtr) /* Maximum block time, or NULL. */ { ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); UINT timeout; /* * Allow the notifier to be hooked. This may not make sense * on Windows, but mirrors the UNIX hook. */ if (tclStubs.tcl_SetTimer != tclOriginalNotifier.setTimerProc) { tclStubs.tcl_SetTimer(timePtr); return; } /* * We only need to set up an interval timer if we're being called * from an external event loop. If we don't have a window handle * then we just return immediately and let Tcl_WaitForEvent handle * timeouts. */ if (!tsdPtr->hwnd) { return; } if (!timePtr) { timeout = 0; } else { /* * Make sure we pass a non-zero value into the timeout argument. * Windows seems to get confused by zero length timers. */ timeout = timePtr->sec * 1000 + timePtr->usec / 1000; if (timeout == 0) { timeout = 1; } } tsdPtr->timeout = timeout; if (timeout != 0) { tsdPtr->timerActive = 1; SetTimer(tsdPtr->hwnd, INTERVAL_TIMER, (unsigned long) tsdPtr->timeout, NULL); } else { tsdPtr->timerActive = 0; KillTimer(tsdPtr->hwnd, INTERVAL_TIMER); } } /* *---------------------------------------------------------------------- * * Tcl_ServiceModeHook -- * * This function is invoked whenever the service mode changes. * * Results: * None. * * Side effects: * If this is the first time the notifier is set into * TCL_SERVICE_ALL, then the communication window is created. * *---------------------------------------------------------------------- */ void Tcl_ServiceModeHook(mode) int mode; /* Either TCL_SERVICE_ALL, or * TCL_SERVICE_NONE. */ { ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); /* * If this is the first time that the notifier has been used from a * modal loop, then create a communication window. Note that after * this point, the application needs to service events in a timely * fashion or Windows will hang waiting for the window to respond * to synchronous system messages. At some point, we may want to * consider destroying the window if we leave the modal loop, but * for now we'll leave it around. */ if (mode == TCL_SERVICE_ALL && !tsdPtr->hwnd) { tsdPtr->hwnd = CreateWindowA("TclNotifier", "TclNotifier", WS_TILED, 0, 0, 0, 0, NULL, NULL, TclWinGetTclInstance(), NULL); /* * Send an initial message to the window to ensure that we wake up the * notifier once we get into the modal loop. This will force the * notifier to recompute the timeout value and schedule a timer * if one is needed. */ Tcl_AlertNotifier((ClientData)tsdPtr); } } /* *---------------------------------------------------------------------- * * NotifierProc -- * * This procedure is invoked by Windows to process events on * the notifier window. Messages will be sent to this window * in response to external timer events or calls to * TclpAlertTsdPtr-> * * Results: * A standard windows result. * * Side effects: * Services any pending events. * *---------------------------------------------------------------------- */ static LRESULT CALLBACK NotifierProc( HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) { ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); if (message == WM_WAKEUP) { EnterCriticalSection(&tsdPtr->crit); tsdPtr->pending = 0; LeaveCriticalSection(&tsdPtr->crit); } else if (message != WM_TIMER) { return DefWindowProc(hwnd, message, wParam, lParam); } /* * Process all of the runnable events. */ Tcl_ServiceAll(); return 0; } /* *---------------------------------------------------------------------- * * Tcl_WaitForEvent -- * * This function is called by Tcl_DoOneEvent to wait for new * events on the message queue. If the block time is 0, then * Tcl_WaitForEvent just polls the event queue without blocking. * * Results: * Returns -1 if a WM_QUIT message is detected, returns 1 if * a message was dispatched, otherwise returns 0. * * Side effects: * Dispatches a message to a window procedure, which could do * anything. * *---------------------------------------------------------------------- */ int Tcl_WaitForEvent( Tcl_Time *timePtr) /* Maximum block time, or NULL. */ { ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); MSG msg; DWORD timeout, result; int status; /* * Allow the notifier to be hooked. This may not make * sense on windows, but mirrors the UNIX hook. */ if (tclStubs.tcl_WaitForEvent != tclOriginalNotifier.waitForEventProc) { return tclStubs.tcl_WaitForEvent(timePtr); } /* * Compute the timeout in milliseconds. */ if (timePtr) { timeout = timePtr->sec * 1000 + timePtr->usec / 1000; } else { timeout = INFINITE; } /* * Check to see if there are any messages in the queue before waiting * because MsgWaitForMultipleObjects will not wake up if there are events * currently sitting in the queue. */ if (!PeekMessage(&msg, NULL, 0, 0, PM_NOREMOVE)) { /* * Wait for something to happen (a signal from another thread, a * message, or timeout) or loop servicing asynchronous procedure * calls queued to this thread. */ again: result = MsgWaitForMultipleObjectsEx(1, &tsdPtr->event, timeout, QS_ALLINPUT, MWMO_ALERTABLE); if (result == WAIT_IO_COMPLETION) { goto again; } else if (result == WAIT_FAILED) { status = -1; goto end; } } /* * Check to see if there are any messages to process. */ if (result == (WAIT_OBJECT_0 + 1) || PeekMessage(&msg, NULL, 0, 0, PM_NOREMOVE)) { /* * Retrieve and dispatch the first message. */ result = GetMessage(&msg, NULL, 0, 0); if (result == 0) { /* * We received a request to exit this thread (WM_QUIT), so * propagate the quit message and start unwinding. */ PostQuitMessage((int) msg.wParam); status = -1; } else if (result == -1) { /* * We got an error from the system. I have no idea why this would * happen, so we'll just unwind. */ status = -1; } else { TranslateMessage(&msg); DispatchMessage(&msg); status = 1; } } else { status = 0; } end: ResetEvent(tsdPtr->event); return status; } /* *---------------------------------------------------------------------- * * Tcl_Sleep -- * * Delay execution for the specified number of milliseconds. * * Results: * None. * * Side effects: * Time passes. * *---------------------------------------------------------------------- */ void Tcl_Sleep(ms) int ms; /* Number of milliseconds to sleep. */ { /* * Simply calling 'Sleep' for the requisite number of milliseconds * can make the process appear to wake up early because it isn't * synchronized with the CPU performance counter that is used in * tclWinTime.c. This behavior is probably benign, but messes * up some of the corner cases in the test suite. We get around * this problem by repeating the 'Sleep' call as many times * as necessary to make the clock advance by the requisite amount. */ Tcl_Time now; /* Current wall clock time */ Tcl_Time desired; /* Desired wakeup time */ DWORD sleepTime = ms; /* Time to sleep */ Tcl_GetTime( &now ); desired.sec = now.sec + ( ms / 1000 ); desired.usec = now.usec + 1000 * ( ms % 1000 ); if ( desired.usec > 1000000 ) { ++desired.sec; desired.usec -= 1000000; } for ( ; ; ) { Sleep( sleepTime ); Tcl_GetTime( &now ); if ( now.sec > desired.sec ) { break; } else if ( ( now.sec == desired.sec ) && ( now.usec >= desired.usec ) ) { break; } sleepTime = ( ( 1000 * ( desired.sec - now.sec ) ) + ( ( desired.usec - now.usec ) / 1000 ) ); } }