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Diffstat (limited to 'generic/tclNotify.c')
-rw-r--r-- | generic/tclNotify.c | 876 |
1 files changed, 876 insertions, 0 deletions
diff --git a/generic/tclNotify.c b/generic/tclNotify.c new file mode 100644 index 0000000..9396248 --- /dev/null +++ b/generic/tclNotify.c @@ -0,0 +1,876 @@ +/* + * tclNotify.c -- + * + * This file implements the generic portion of the Tcl notifier. + * The notifier is lowest-level part of the event system. It + * manages an event queue that holds Tcl_Event structures. The + * platform specific portion of the notifier is defined in the + * tcl*Notify.c files in each platform directory. + * + * 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. + * + * SCCS: @(#) tclNotify.c 1.16 97/09/15 15:12:52 + */ + +#include "tclInt.h" +#include "tclPort.h" + +/* + * The following static indicates whether this module has been initialized. + */ + +static int initialized = 0; + +/* + * For each event source (created with Tcl_CreateEventSource) there + * is a structure of the following type: + */ + +typedef struct EventSource { + Tcl_EventSetupProc *setupProc; + Tcl_EventCheckProc *checkProc; + ClientData clientData; + struct EventSource *nextPtr; +} EventSource; + +/* + * The following structure keeps track of the state of the notifier. + * The first three elements keep track of the event queue. In addition to + * the first (next to be serviced) and last events in the queue, we keep + * track of a "marker" event. This provides a simple priority mechanism + * whereby events can be inserted at the front of the queue but behind all + * other high-priority events already in the queue (this is used for things + * like a sequence of Enter and Leave events generated during a grab in + * Tk). + */ + +static struct { + Tcl_Event *firstEventPtr; /* First pending event, or NULL if none. */ + Tcl_Event *lastEventPtr; /* Last pending event, or NULL if none. */ + Tcl_Event *markerEventPtr; /* Last high-priority event in queue, or + * NULL if none. */ + int serviceMode; /* One of TCL_SERVICE_NONE or + * TCL_SERVICE_ALL. */ + int blockTimeSet; /* 0 means there is no maximum block + * time: block forever. */ + Tcl_Time blockTime; /* If blockTimeSet is 1, gives the + * maximum elapsed time for the next block. */ + int inTraversal; /* 1 if Tcl_SetMaxBlockTime is being + * called during an event source traversal. */ + EventSource *firstEventSourcePtr; + /* Pointer to first event source in + * global list of event sources. */ +} notifier; + +/* + * Declarations for functions used in this file. + */ + +static void InitNotifier _ANSI_ARGS_((void)); +static void NotifierExitHandler _ANSI_ARGS_((ClientData clientData)); + + +/* + *---------------------------------------------------------------------- + * + * InitNotifier -- + * + * This routine is called to initialize the notifier module. + * + * Results: + * None. + * + * Side effects: + * Creates an exit handler and initializes static data. + * + *---------------------------------------------------------------------- + */ + +static void +InitNotifier() +{ + initialized = 1; + memset(¬ifier, 0, sizeof(notifier)); + notifier.serviceMode = TCL_SERVICE_NONE; + Tcl_CreateExitHandler(NotifierExitHandler, NULL); +} + +/* + *---------------------------------------------------------------------- + * + * NotifierExitHandler -- + * + * This routine is called during Tcl finalization. + * + * Results: + * None. + * + * Side effects: + * Clears the notifier intialization flag. + * + *---------------------------------------------------------------------- + */ + +static void +NotifierExitHandler(clientData) + ClientData clientData; /* Not used. */ +{ + initialized = 0; +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_CreateEventSource -- + * + * This procedure is invoked to create a new source of events. + * The source is identified by a procedure that gets invoked + * during Tcl_DoOneEvent to check for events on that source + * and queue them. + * + * + * Results: + * None. + * + * Side effects: + * SetupProc and checkProc will be invoked each time that Tcl_DoOneEvent + * runs out of things to do. SetupProc will be invoked before + * Tcl_DoOneEvent calls select or whatever else it uses to wait + * for events. SetupProc typically calls functions like Tcl_WatchFile + * or Tcl_SetMaxBlockTime to indicate what to wait for. + * + * CheckProc is called after select or whatever operation was actually + * used to wait. It figures out whether anything interesting actually + * happened (e.g. by calling Tcl_FileReady), and then calls + * Tcl_QueueEvent to queue any events that are ready. + * + * Each of these procedures is passed two arguments, e.g. + * (*checkProc)(ClientData clientData, int flags)); + * ClientData is the same as the clientData argument here, and flags + * is a combination of things like TCL_FILE_EVENTS that indicates + * what events are of interest: setupProc and checkProc use flags + * to figure out whether their events are relevant or not. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_CreateEventSource(setupProc, checkProc, clientData) + Tcl_EventSetupProc *setupProc; /* Procedure to invoke to figure out + * what to wait for. */ + Tcl_EventCheckProc *checkProc; /* Procedure to call after waiting + * to see what happened. */ + ClientData clientData; /* One-word argument to pass to + * setupProc and checkProc. */ +{ + EventSource *sourcePtr; + + if (!initialized) { + InitNotifier(); + } + + sourcePtr = (EventSource *) ckalloc(sizeof(EventSource)); + sourcePtr->setupProc = setupProc; + sourcePtr->checkProc = checkProc; + sourcePtr->clientData = clientData; + sourcePtr->nextPtr = notifier.firstEventSourcePtr; + notifier.firstEventSourcePtr = sourcePtr; +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_DeleteEventSource -- + * + * This procedure is invoked to delete the source of events + * given by proc and clientData. + * + * Results: + * None. + * + * Side effects: + * The given event source is cancelled, so its procedure will + * never again be called. If no such source exists, nothing + * happens. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_DeleteEventSource(setupProc, checkProc, clientData) + Tcl_EventSetupProc *setupProc; /* Procedure to invoke to figure out + * what to wait for. */ + Tcl_EventCheckProc *checkProc; /* Procedure to call after waiting + * to see what happened. */ + ClientData clientData; /* One-word argument to pass to + * setupProc and checkProc. */ +{ + EventSource *sourcePtr, *prevPtr; + + for (sourcePtr = notifier.firstEventSourcePtr, prevPtr = NULL; + sourcePtr != NULL; + prevPtr = sourcePtr, sourcePtr = sourcePtr->nextPtr) { + if ((sourcePtr->setupProc != setupProc) + || (sourcePtr->checkProc != checkProc) + || (sourcePtr->clientData != clientData)) { + continue; + } + if (prevPtr == NULL) { + notifier.firstEventSourcePtr = sourcePtr->nextPtr; + } else { + prevPtr->nextPtr = sourcePtr->nextPtr; + } + ckfree((char *) sourcePtr); + return; + } +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_QueueEvent -- + * + * Insert an event into the Tk 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. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_QueueEvent(evPtr, position) + 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. */ +{ + if (!initialized) { + InitNotifier(); + } + + if (position == TCL_QUEUE_TAIL) { + /* + * Append the event on the end of the queue. + */ + + evPtr->nextPtr = NULL; + if (notifier.firstEventPtr == NULL) { + notifier.firstEventPtr = evPtr; + } else { + notifier.lastEventPtr->nextPtr = evPtr; + } + notifier.lastEventPtr = evPtr; + } else if (position == TCL_QUEUE_HEAD) { + /* + * Push the event on the head of the queue. + */ + + evPtr->nextPtr = notifier.firstEventPtr; + if (notifier.firstEventPtr == NULL) { + notifier.lastEventPtr = evPtr; + } + notifier.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 (notifier.markerEventPtr == NULL) { + evPtr->nextPtr = notifier.firstEventPtr; + notifier.firstEventPtr = evPtr; + } else { + evPtr->nextPtr = notifier.markerEventPtr->nextPtr; + notifier.markerEventPtr->nextPtr = evPtr; + } + notifier.markerEventPtr = evPtr; + if (evPtr->nextPtr == NULL) { + notifier.lastEventPtr = evPtr; + } + } +} + +/* + *---------------------------------------------------------------------- + * + * 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. + * + * 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; + + if (!initialized) { + InitNotifier(); + } + + for (prevPtr = (Tcl_Event *) NULL, evPtr = notifier.firstEventPtr; + evPtr != (Tcl_Event *) NULL; + ) { + if ((*proc) (evPtr, clientData) == 1) { + if (notifier.firstEventPtr == evPtr) { + notifier.firstEventPtr = evPtr->nextPtr; + if (evPtr->nextPtr == (Tcl_Event *) NULL) { + notifier.lastEventPtr = (Tcl_Event *) NULL; + } + } else { + prevPtr->nextPtr = evPtr->nextPtr; + } + hold = evPtr; + evPtr = evPtr->nextPtr; + ckfree((char *) hold); + } else { + prevPtr = evPtr; + evPtr = evPtr->nextPtr; + } + } +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_ServiceEvent -- + * + * Process one event from the event queue, or invoke an + * asynchronous event handler. + * + * 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; + + if (!initialized) { + InitNotifier(); + } + + /* + * 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. + */ + + for (evPtr = notifier.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, but 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; + evPtr->proc = NULL; + if ((proc != NULL) && (*proc)(evPtr, flags)) { + if (notifier.firstEventPtr == evPtr) { + notifier.firstEventPtr = evPtr->nextPtr; + if (evPtr->nextPtr == NULL) { + notifier.lastEventPtr = NULL; + } + if (notifier.markerEventPtr == evPtr) { + notifier.markerEventPtr = NULL; + } + } else { + for (prevPtr = notifier.firstEventPtr; + prevPtr->nextPtr != evPtr; prevPtr = prevPtr->nextPtr) { + /* Empty loop body. */ + } + prevPtr->nextPtr = evPtr->nextPtr; + if (evPtr->nextPtr == NULL) { + notifier.lastEventPtr = prevPtr; + } + if (notifier.markerEventPtr == evPtr) { + notifier.markerEventPtr = prevPtr; + } + } + ckfree((char *) evPtr); + 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; + } + + /* + * The handler for this event asked to defer it. Just go on to + * the next event. + */ + + continue; + } + 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() +{ + if (!initialized) { + InitNotifier(); + } + + return notifier.serviceMode; +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_SetServiceMode -- + * + * This routine sets the current service mode of the notifier. + * + * Results: + * Returns the previous service mode. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +int +Tcl_SetServiceMode(mode) + int mode; /* New service mode: TCL_SERVICE_ALL or + * TCL_SERVICE_NONE */ +{ + int oldMode; + + if (!initialized) { + InitNotifier(); + } + + oldMode = notifier.serviceMode; + notifier.serviceMode = mode; + return oldMode; +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_SetMaxBlockTime -- + * + * 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 notifier. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_SetMaxBlockTime(timePtr) + Tcl_Time *timePtr; /* Specifies a maximum elapsed time for + * the next blocking operation in the + * event notifier. */ +{ + if (!initialized) { + InitNotifier(); + } + + if (!notifier.blockTimeSet || (timePtr->sec < notifier.blockTime.sec) + || ((timePtr->sec == notifier.blockTime.sec) + && (timePtr->usec < notifier.blockTime.usec))) { + notifier.blockTime = *timePtr; + notifier.blockTimeSet = 1; + } + + /* + * If we are called outside an event source traversal, set the + * timeout immediately. + */ + + if (!notifier.inTraversal) { + if (notifier.blockTimeSet) { + Tcl_SetTimer(¬ifier.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; + + if (!initialized) { + InitNotifier(); + } + + /* + * 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 = notifier.serviceMode; + notifier.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) { + notifier.blockTime.sec = 0; + notifier.blockTime.usec = 0; + notifier.blockTimeSet = 1; + } else { + notifier.blockTimeSet = 0; + } + + /* + * Set up all the event sources for new events. This will + * cause the block time to be updated if necessary. + */ + + notifier.inTraversal = 1; + for (sourcePtr = notifier.firstEventSourcePtr; sourcePtr != NULL; + sourcePtr = sourcePtr->nextPtr) { + if (sourcePtr->setupProc) { + (sourcePtr->setupProc)(sourcePtr->clientData, flags); + } + } + notifier.inTraversal = 0; + + if ((flags & TCL_DONT_WAIT) || notifier.blockTimeSet) { + timePtr = ¬ifier.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 = notifier.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; + } + + } + + notifier.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; + + if (!initialized) { + InitNotifier(); + } + + if (notifier.serviceMode == TCL_SERVICE_NONE) { + return result; + } + + /* + * We need to turn off event servicing like we to in Tcl_DoOneEvent, + * to avoid recursive calls. + */ + + notifier.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. + */ + + notifier.inTraversal = 1; + notifier.blockTimeSet = 0; + + for (sourcePtr = notifier.firstEventSourcePtr; sourcePtr != NULL; + sourcePtr = sourcePtr->nextPtr) { + if (sourcePtr->setupProc) { + (sourcePtr->setupProc)(sourcePtr->clientData, TCL_ALL_EVENTS); + } + } + for (sourcePtr = notifier.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 (!notifier.blockTimeSet) { + Tcl_SetTimer(NULL); + } else { + Tcl_SetTimer(¬ifier.blockTime); + } + notifier.inTraversal = 0; + notifier.serviceMode = TCL_SERVICE_ALL; + return result; +} |