tclnotify.c

tcl是工具命令语言

    Tcl_ThreadId threadId;	/* Identifier for thread to use. */
    Tcl_Event* evPtr;		/* Event to add to queue.  The storage
				 * space must have been allocated the caller
				 * with malloc (ckalloc), and it becomes
				 * the property of the event queue.  It
				 * will be freed after the event has been
				 * handled. */
    Tcl_QueuePosition position;	/* One of TCL_QUEUE_TAIL, TCL_QUEUE_HEAD,
				 * TCL_QUEUE_MARK. */
{
    ThreadSpecificData *tsdPtr;

    /*
     * Find the notifier associated with the specified thread.
     */

    Tcl_MutexLock(&listLock);
    for (tsdPtr = firstNotifierPtr; tsdPtr && tsdPtr->threadId != threadId;
	     tsdPtr = tsdPtr->nextPtr) {
	/* Empty loop body. */
    }

    /*
     * Queue the event if there was a notifier associated with the thread.
     */

    if (tsdPtr) {
	QueueEvent(tsdPtr, evPtr, position);
    }
    Tcl_MutexUnlock(&listLock);
}

/*
 *----------------------------------------------------------------------
 *
 * QueueEvent --
 *
 *	Insert an event into the specified thread's event queue at one
 *	of three positions: the head, the tail, or before a floating
 *	marker. Events inserted before the marker will be processed in
 *	first-in-first-out order, but before any events inserted at
 *	the tail of the queue.  Events inserted at the head of the
 *	queue will be processed in last-in-first-out order.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static void
QueueEvent(tsdPtr, evPtr, position)
    ThreadSpecificData *tsdPtr;	/* Handle to thread local data that indicates
				 * which event queue to use. */
    Tcl_Event* evPtr;		/* Event to add to queue.  The storage
				 * space must have been allocated the caller
				 * with malloc (ckalloc), and it becomes
				 * the property of the event queue.  It
				 * will be freed after the event has been
				 * handled. */
    Tcl_QueuePosition position;	/* One of TCL_QUEUE_TAIL, TCL_QUEUE_HEAD,
				 * TCL_QUEUE_MARK. */
{
    Tcl_MutexLock(&(tsdPtr->queueMutex));
    if (position == TCL_QUEUE_TAIL) {
	/*
	 * Append the event on the end of the queue.
	 */

	evPtr->nextPtr = NULL;
	if (tsdPtr->firstEventPtr == NULL) {
	    tsdPtr->firstEventPtr = evPtr;
	} else {
	    tsdPtr->lastEventPtr->nextPtr = evPtr;
	}
	tsdPtr->lastEventPtr = evPtr;
    } else if (position == TCL_QUEUE_HEAD) {
	/*
	 * Push the event on the head of the queue.
	 */

	evPtr->nextPtr = tsdPtr->firstEventPtr;
	if (tsdPtr->firstEventPtr == NULL) {
	    tsdPtr->lastEventPtr = evPtr;
	}	    
	tsdPtr->firstEventPtr = evPtr;
    } else if (position == TCL_QUEUE_MARK) {
	/*
	 * Insert the event after the current marker event and advance
	 * the marker to the new event.
	 */

	if (tsdPtr->markerEventPtr == NULL) {
	    evPtr->nextPtr = tsdPtr->firstEventPtr;
	    tsdPtr->firstEventPtr = evPtr;
	} else {
	    evPtr->nextPtr = tsdPtr->markerEventPtr->nextPtr;
	    tsdPtr->markerEventPtr->nextPtr = evPtr;
	}
	tsdPtr->markerEventPtr = evPtr;
	if (evPtr->nextPtr == NULL) {
	    tsdPtr->lastEventPtr = evPtr;
	}
    }
    Tcl_MutexUnlock(&(tsdPtr->queueMutex));
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_DeleteEvents --
 *
 *	Calls a procedure for each event in the queue and deletes those
 *	for which the procedure returns 1. Events for which the
 *	procedure returns 0 are left in the queue.  Operates on the
 *	queue associated with the current thread.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Potentially removes one or more events from the event queue.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_DeleteEvents(proc, clientData)
    Tcl_EventDeleteProc *proc;		/* The procedure to call. */
    ClientData clientData;    		/* type-specific data. */
{
    Tcl_Event *evPtr, *prevPtr, *hold;
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    Tcl_MutexLock(&(tsdPtr->queueMutex));
    for (prevPtr = (Tcl_Event *) NULL, evPtr = tsdPtr->firstEventPtr;
             evPtr != (Tcl_Event *) NULL;
             ) {
        if ((*proc) (evPtr, clientData) == 1) {
            if (tsdPtr->firstEventPtr == evPtr) {
                tsdPtr->firstEventPtr = evPtr->nextPtr;
            } else {
                prevPtr->nextPtr = evPtr->nextPtr;
            }
            if (evPtr->nextPtr == (Tcl_Event *) NULL) {
                tsdPtr->lastEventPtr = prevPtr;
            }
            if (tsdPtr->markerEventPtr == evPtr) {
                tsdPtr->markerEventPtr = prevPtr;
            }
            hold = evPtr;
            evPtr = evPtr->nextPtr;
            ckfree((char *) hold);
        } else {
            prevPtr = evPtr;
            evPtr = evPtr->nextPtr;
        }
    }
    Tcl_MutexUnlock(&(tsdPtr->queueMutex));
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_ServiceEvent --
 *
 *	Process one event from the event queue, or invoke an
 *	asynchronous event handler.  Operates on event queue for
 *	current thread.
 *
 * Results:
 *	The return value is 1 if the procedure actually found an event
 *	to process.  If no processing occurred, then 0 is returned.
 *
 * Side effects:
 *	Invokes all of the event handlers for the highest priority
 *	event in the event queue.  May collapse some events into a
 *	single event or discard stale events.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_ServiceEvent(flags)
    int flags;			/* Indicates what events should be processed.
				 * May be any combination of TCL_WINDOW_EVENTS
				 * TCL_FILE_EVENTS, TCL_TIMER_EVENTS, or other
				 * flags defined elsewhere.  Events not
				 * matching this will be skipped for processing
				 * later. */
{
    Tcl_Event *evPtr, *prevPtr;
    Tcl_EventProc *proc;
    int result;
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    /*
     * Asynchronous event handlers are considered to be the highest
     * priority events, and so must be invoked before we process events
     * on the event queue.
     */
    
    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;
    }

    /*
     * Loop through all the events in the queue until we find one
     * that can actually be handled.
     */

    Tcl_MutexLock(&(tsdPtr->queueMutex));
    for (evPtr = tsdPtr->firstEventPtr; evPtr != NULL;
	 evPtr = evPtr->nextPtr) {
	/*
	 * Call the handler for the event.  If it actually handles the
	 * event then free the storage for the event.  There are two
	 * tricky things here, both stemming from the fact that the event
	 * code may be re-entered while servicing the event:
	 *
	 * 1. Set the "proc" field to NULL.  This is a signal to ourselves
	 *    that we shouldn't reexecute the handler if the event loop
	 *    is re-entered.
	 * 2. When freeing the event, must search the queue again from the
	 *    front to find it.  This is because the event queue could
	 *    change almost arbitrarily while handling the event, so we
	 *    can't depend on pointers found now still being valid when
	 *    the handler returns.
	 */

	proc = evPtr->proc;
	if (proc == NULL) {
	    continue;
	}
	evPtr->proc = NULL;

	/*
	 * Release the lock before calling the event procedure.  This
	 * allows other threads to post events if we enter a recursive
	 * event loop in this thread.  Note that we are making the assumption
	 * that if the proc returns 0, the event is still in the list.
	 */

	Tcl_MutexUnlock(&(tsdPtr->queueMutex));
	result = (*proc)(evPtr, flags);
	Tcl_MutexLock(&(tsdPtr->queueMutex));

	if (result) {
	    /*
	     * The event was processed, so remove it from the queue.
	     */

	    if (tsdPtr->firstEventPtr == evPtr) {
		tsdPtr->firstEventPtr = evPtr->nextPtr;
		if (evPtr->nextPtr == NULL) {
		    tsdPtr->lastEventPtr = NULL;
		}
		if (tsdPtr->markerEventPtr == evPtr) {
		    tsdPtr->markerEventPtr = NULL;
		}
	    } else {
		for (prevPtr = tsdPtr->firstEventPtr;
		     prevPtr && prevPtr->nextPtr != evPtr;
		     prevPtr = prevPtr->nextPtr) {
		    /* Empty loop body. */
		}
		if (prevPtr) {
		    prevPtr->nextPtr = evPtr->nextPtr;
		    if (evPtr->nextPtr == NULL) {
			tsdPtr->lastEventPtr = prevPtr;
		    }
		    if (tsdPtr->markerEventPtr == evPtr) {
			tsdPtr->markerEventPtr = prevPtr;
		    }
		} else {
		    evPtr = NULL;
		}
	    }
	    if (evPtr) {
		ckfree((char *) evPtr);
	    }
	    Tcl_MutexUnlock(&(tsdPtr->queueMutex));
	    return 1;
	} else {
	    /*
	     * The event wasn't actually handled, so we have to restore
	     * the proc field to allow the event to be attempted again.
	     */

	    evPtr->proc = proc;
	}
    }
    Tcl_MutexUnlock(&(tsdPtr->queueMutex));
    return 0;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_GetServiceMode --
 *
 *	This routine returns the current service mode of the notifier.
 *
 * Results:
 *	Returns either TCL_SERVICE_ALL or TCL_SERVICE_NONE.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_GetServiceMode()
{
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    return tsdPtr->serviceMode;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_SetServiceMode --
 *
 *	This routine sets the current service mode of the tsdPtr->
 *
 * Results:
 *	Returns the previous service mode.
 *
 * Side effects:
 *	Invokes the notifier service mode hook procedure.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_SetServiceMode(mode)
    int mode;			/* New service mode: TCL_SERVICE_ALL or
				 * TCL_SERVICE_NONE */
{
    int oldMode;
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    oldMode = tsdPtr->serviceMode;
    tsdPtr->serviceMode = mode;
    if (tclStubs.tcl_ServiceModeHook) {
	tclStubs.tcl_ServiceModeHook(mode);
    }
    return oldMode;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_SetMaxBlockTime --