tclnotify.c

tcl是工具命令语言

 *
 *	This procedure is invoked by event sources to tell the notifier
 *	how long it may block the next time it blocks.  The timePtr
 *	argument gives a maximum time;  the actual time may be less if
 *	some other event source requested a smaller time.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	May reduce the length of the next sleep in the tsdPtr->
 *
 *----------------------------------------------------------------------
 */

void
Tcl_SetMaxBlockTime(timePtr)
    Tcl_Time *timePtr;		/* Specifies a maximum elapsed time for
				 * the next blocking operation in the
				 * event tsdPtr-> */
{
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    if (!tsdPtr->blockTimeSet || (timePtr->sec < tsdPtr->blockTime.sec)
	    || ((timePtr->sec == tsdPtr->blockTime.sec)
	    && (timePtr->usec < tsdPtr->blockTime.usec))) {
	tsdPtr->blockTime = *timePtr;
	tsdPtr->blockTimeSet = 1;
    }

    /*
     * If we are called outside an event source traversal, set the
     * timeout immediately.
     */

    if (!tsdPtr->inTraversal) {
	if (tsdPtr->blockTimeSet) {
	    Tcl_SetTimer(&tsdPtr->blockTime);
	} else {
	    Tcl_SetTimer(NULL);
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_DoOneEvent --
 *
 *	Process a single event of some sort.  If there's no work to
 *	do, wait for an event to occur, then process it.
 *
 * Results:
 *	The return value is 1 if the procedure actually found an event
 *	to process.  If no processing occurred, then 0 is returned (this
 *	can happen if the TCL_DONT_WAIT flag is set or if there are no
 *	event handlers to wait for in the set specified by flags).
 *
 * Side effects:
 *	May delay execution of process while waiting for an event,
 *	unless TCL_DONT_WAIT is set in the flags argument.  Event
 *	sources are invoked to check for and queue events.  Event
 *	handlers may produce arbitrary side effects.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_DoOneEvent(flags)
    int flags;			/* Miscellaneous flag values:  may be any
				 * combination of TCL_DONT_WAIT,
				 * TCL_WINDOW_EVENTS, TCL_FILE_EVENTS,
				 * TCL_TIMER_EVENTS, TCL_IDLE_EVENTS, or
				 * others defined by event sources. */
{
    int result = 0, oldMode;
    EventSource *sourcePtr;
    Tcl_Time *timePtr;
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    /*
     * The first thing we do is to service any asynchronous event
     * handlers.
     */
    
    if (Tcl_AsyncReady()) {
	(void) Tcl_AsyncInvoke((Tcl_Interp *) NULL, 0);
	return 1;
    }

    /*
     * No event flags is equivalent to TCL_ALL_EVENTS.
     */
    
    if ((flags & TCL_ALL_EVENTS) == 0) {
	flags |= TCL_ALL_EVENTS;
    }

    /*
     * Set the service mode to none so notifier event routines won't
     * try to service events recursively.
     */

    oldMode = tsdPtr->serviceMode;
    tsdPtr->serviceMode = TCL_SERVICE_NONE;

    /*
     * The core of this procedure is an infinite loop, even though
     * we only service one event.  The reason for this is that we
     * may be processing events that don't do anything inside of Tcl.
     */

    while (1) {

	/*
	 * If idle events are the only things to service, skip the
	 * main part of the loop and go directly to handle idle
	 * events (i.e. don't wait even if TCL_DONT_WAIT isn't set).
	 */

	if ((flags & TCL_ALL_EVENTS) == TCL_IDLE_EVENTS) {
	    flags = TCL_IDLE_EVENTS|TCL_DONT_WAIT;
	    goto idleEvents;
	}

	/*
	 * Ask Tcl to service a queued event, if there are any.
	 */

	if (Tcl_ServiceEvent(flags)) {
	    result = 1;	    
	    break;
	}

	/*
	 * If TCL_DONT_WAIT is set, be sure to poll rather than
	 * blocking, otherwise reset the block time to infinity.
	 */

	if (flags & TCL_DONT_WAIT) {
	    tsdPtr->blockTime.sec = 0;
	    tsdPtr->blockTime.usec = 0;
	    tsdPtr->blockTimeSet = 1;
	} else {
	    tsdPtr->blockTimeSet = 0;
	}

	/*
	 * Set up all the event sources for new events.  This will
	 * cause the block time to be updated if necessary.
	 */

	tsdPtr->inTraversal = 1;
	for (sourcePtr = tsdPtr->firstEventSourcePtr; sourcePtr != NULL;
	     sourcePtr = sourcePtr->nextPtr) {
	    if (sourcePtr->setupProc) {
		(sourcePtr->setupProc)(sourcePtr->clientData, flags);
	    }
	}
	tsdPtr->inTraversal = 0;

	if ((flags & TCL_DONT_WAIT) || tsdPtr->blockTimeSet) {
	    timePtr = &tsdPtr->blockTime;
	} else {
	    timePtr = NULL;
	}

	/*
	 * Wait for a new event or a timeout.  If Tcl_WaitForEvent
	 * returns -1, we should abort Tcl_DoOneEvent.
	 */

	result = Tcl_WaitForEvent(timePtr);
	if (result < 0) {
	    result = 0;
	    break;
	}

	/*
	 * Check all the event sources for new events.
	 */

	for (sourcePtr = tsdPtr->firstEventSourcePtr; sourcePtr != NULL;
	     sourcePtr = sourcePtr->nextPtr) {
	    if (sourcePtr->checkProc) {
		(sourcePtr->checkProc)(sourcePtr->clientData, flags);
	    }
	}

	/*
	 * Check for events queued by the notifier or event sources.
	 */

	if (Tcl_ServiceEvent(flags)) {
	    result = 1;
	    break;
	}

	/*
	 * We've tried everything at this point, but nobody we know
	 * about had anything to do.  Check for idle events.  If none,
	 * either quit or go back to the top and try again.
	 */

	idleEvents:
	if (flags & TCL_IDLE_EVENTS) {
	    if (TclServiceIdle()) {
		result = 1;
		break;
	    }
	}
	if (flags & TCL_DONT_WAIT) {
	    break;
	}

	/*
	 * If Tcl_WaitForEvent has returned 1,
	 * indicating that one system event has been dispatched
	 * (and thus that some Tcl code might have been indirectly executed),
	 * we break out of the loop.
	 * We do this to give VwaitCmd for instance a chance to check 
	 * if that system event had the side effect of changing the 
	 * variable (so the vwait can return and unwind properly).
	 *
	 * NB: We will process idle events if any first, because
	 *     otherwise we might never do the idle events if the notifier
	 *     always gets system events.
	 */

	if (result) {
	    break;
	}

    }

    tsdPtr->serviceMode = oldMode;
    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_ServiceAll --
 *
 *	This routine checks all of the event sources, processes
 *	events that are on the Tcl event queue, and then calls the
 *	any idle handlers.  Platform specific notifier callbacks that
 *	generate events should call this routine before returning to
 *	the system in order to ensure that Tcl gets a chance to
 *	process the new events.
 *
 * Results:
 *	Returns 1 if an event or idle handler was invoked, else 0.
 *
 * Side effects:
 *	Anything that an event or idle handler may do.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_ServiceAll()
{
    int result = 0;
    EventSource *sourcePtr;
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    if (tsdPtr->serviceMode == TCL_SERVICE_NONE) {
	return result;
    }

    /*
     * We need to turn off event servicing like we to in Tcl_DoOneEvent,
     * to avoid recursive calls.
     */
    
    tsdPtr->serviceMode = TCL_SERVICE_NONE;

    /*
     * Check async handlers first.
     */

    if (Tcl_AsyncReady()) {
	(void) Tcl_AsyncInvoke((Tcl_Interp *) NULL, 0);
    }

    /*
     * Make a single pass through all event sources, queued events,
     * and idle handlers.  Note that we wait to update the notifier
     * timer until the end so we can avoid multiple changes.
     */

    tsdPtr->inTraversal = 1;
    tsdPtr->blockTimeSet = 0;

    for (sourcePtr = tsdPtr->firstEventSourcePtr; sourcePtr != NULL;
	 sourcePtr = sourcePtr->nextPtr) {
	if (sourcePtr->setupProc) {
	    (sourcePtr->setupProc)(sourcePtr->clientData, TCL_ALL_EVENTS);
	}
    }
    for (sourcePtr = tsdPtr->firstEventSourcePtr; sourcePtr != NULL;
	 sourcePtr = sourcePtr->nextPtr) {
	if (sourcePtr->checkProc) {
	    (sourcePtr->checkProc)(sourcePtr->clientData, TCL_ALL_EVENTS);
	}
    }

    while (Tcl_ServiceEvent(0)) {
	result = 1;
    }
    if (TclServiceIdle()) {
	result = 1;
    }

    if (!tsdPtr->blockTimeSet) {
	Tcl_SetTimer(NULL);
    } else {
	Tcl_SetTimer(&tsdPtr->blockTime);
    }
    tsdPtr->inTraversal = 0;
    tsdPtr->serviceMode = TCL_SERVICE_ALL;
    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_ThreadAlert --
 *
 *	This function wakes up the notifier associated with the
 *	specified thread (if there is one).  
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_ThreadAlert(threadId)
    Tcl_ThreadId threadId;	/* Identifier for thread to use. */
{
    ThreadSpecificData *tsdPtr;

    /*
     * Find the notifier associated with the specified thread.
     * Note that we need to hold the listLock while calling
     * Tcl_AlertNotifier to avoid a race condition where
     * the specified thread might destroy its notifier.
     */

    Tcl_MutexLock(&listLock);
    for (tsdPtr = firstNotifierPtr; tsdPtr; tsdPtr = tsdPtr->nextPtr) {
	if (tsdPtr->threadId == threadId) {
	    if (tclStubs.tcl_AlertNotifier) {
		tclStubs.tcl_AlertNotifier(tsdPtr->clientData);
	    }
	    break;
	}
    }
    Tcl_MutexUnlock(&listLock);
}