diff options
Diffstat (limited to 'generic/tclNotify.c')
| -rw-r--r-- | generic/tclNotify.c | 1141 |
1 files changed, 1141 insertions, 0 deletions
diff --git a/generic/tclNotify.c b/generic/tclNotify.c new file mode 100644 index 0000000..e76bca8 --- /dev/null +++ b/generic/tclNotify.c @@ -0,0 +1,1141 @@ +/* + * 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. + * Copyright (c) 1998 by Scriptics Corporation. + * Copyright (c) 2003 by Kevin B. Kenny. All rights reserved. + * + * See the file "license.terms" for information on usage and redistribution of + * this file, and for a DISCLAIMER OF ALL WARRANTIES. + */ + +#include "tclInt.h" + +/* + * Module-scope struct of notifier hooks that are checked in the default + * notifier functions (for overriding via Tcl_SetNotifier). + */ + +Tcl_NotifierProcs tclNotifierHooks = { + NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL +}; + +/* + * 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 on a + * per-thread basis. 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). These elements are protected by the queueMutex so that any + * thread can queue an event on any notifier. Note that all of the values in + * this structure will be initialized to 0. + */ + +typedef struct ThreadSpecificData { + 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. */ + Tcl_Mutex queueMutex; /* Mutex to protect access to the previous + * three fields. */ + 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 list of + * event sources for this thread. */ + Tcl_ThreadId threadId; /* Thread that owns this notifier instance. */ + ClientData clientData; /* Opaque handle for platform specific + * notifier. */ + int initialized; /* 1 if notifier has been initialized. */ + struct ThreadSpecificData *nextPtr; + /* Next notifier in global list of notifiers. + * Access is controlled by the listLock global + * mutex. */ +} ThreadSpecificData; + +static Tcl_ThreadDataKey dataKey; + +/* + * Global list of notifiers. Access to this list is controlled by the listLock + * mutex. If this becomes a performance bottleneck, this could be replaced + * with a hashtable. + */ + +static ThreadSpecificData *firstNotifierPtr = NULL; +TCL_DECLARE_MUTEX(listLock) + +/* + * Declarations for routines used only in this file. + */ + +static void QueueEvent(ThreadSpecificData *tsdPtr, + Tcl_Event *evPtr, Tcl_QueuePosition position); + +/* + *---------------------------------------------------------------------- + * + * TclInitNotifier -- + * + * Initialize the thread local data structures for the notifier + * subsystem. + * + * Results: + * None. + * + * Side effects: + * Adds the current thread to the global list of notifiers. + * + *---------------------------------------------------------------------- + */ + +void +TclInitNotifier(void) +{ + ThreadSpecificData *tsdPtr; + Tcl_ThreadId threadId = Tcl_GetCurrentThread(); + + Tcl_MutexLock(&listLock); + for (tsdPtr = firstNotifierPtr; tsdPtr && tsdPtr->threadId != threadId; + tsdPtr = tsdPtr->nextPtr) { + /* Empty loop body. */ + } + + if (NULL == tsdPtr) { + /* + * Notifier not yet initialized in this thread. + */ + + tsdPtr = TCL_TSD_INIT(&dataKey); + tsdPtr->threadId = threadId; + tsdPtr->clientData = Tcl_InitNotifier(); + tsdPtr->initialized = 1; + tsdPtr->nextPtr = firstNotifierPtr; + firstNotifierPtr = tsdPtr; + } + Tcl_MutexUnlock(&listLock); +} + +/* + *---------------------------------------------------------------------- + * + * TclFinalizeNotifier -- + * + * Finalize the thread local data structures for the notifier subsystem. + * + * Results: + * None. + * + * Side effects: + * Removes the notifier associated with the current thread from the + * global notifier list. This is done only if the notifier was + * initialized for this thread by call to TclInitNotifier(). This is + * always true for threads which have been seeded with an Tcl + * interpreter, since the call to Tcl_CreateInterp will, among other + * things, call TclInitializeSubsystems() and this one will, in turn, + * call the TclInitNotifier() for the thread. For threads created without + * the Tcl interpreter, though, nobody is explicitly nor implicitly + * calling the TclInitNotifier hence, TclFinalizeNotifier should not be + * performed at all. + * + *---------------------------------------------------------------------- + */ + +void +TclFinalizeNotifier(void) +{ + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); + ThreadSpecificData **prevPtrPtr; + Tcl_Event *evPtr, *hold; + + if (!tsdPtr->initialized) { + return; /* Notifier not initialized for the current thread */ + } + + Tcl_MutexLock(&(tsdPtr->queueMutex)); + for (evPtr = tsdPtr->firstEventPtr; evPtr != NULL; ) { + hold = evPtr; + evPtr = evPtr->nextPtr; + ckfree(hold); + } + tsdPtr->firstEventPtr = NULL; + tsdPtr->lastEventPtr = NULL; + Tcl_MutexUnlock(&(tsdPtr->queueMutex)); + + Tcl_MutexLock(&listLock); + + Tcl_FinalizeNotifier(tsdPtr->clientData); + Tcl_MutexFinalize(&(tsdPtr->queueMutex)); + for (prevPtrPtr = &firstNotifierPtr; *prevPtrPtr != NULL; + prevPtrPtr = &((*prevPtrPtr)->nextPtr)) { + if (*prevPtrPtr == tsdPtr) { + *prevPtrPtr = tsdPtr->nextPtr; + break; + } + } + tsdPtr->initialized = 0; + + Tcl_MutexUnlock(&listLock); +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_SetNotifier -- + * + * Install a set of alternate functions for use with the notifier. In + * particular, this can be used to install the Xt-based notifier for use + * with the Browser plugin. + * + * Results: + * None. + * + * Side effects: + * Set the tclNotifierHooks global, which is checked in the default + * notifier functions. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_SetNotifier( + Tcl_NotifierProcs *notifierProcPtr) +{ + tclNotifierHooks = *notifierProcPtr; +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_CreateEventSource -- + * + * This function is invoked to create a new source of events. The source + * is identified by a function 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_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_AsyncReady), and then calls + * Tcl_QueueEvent to queue any events that are ready. + * + * Each of these functions 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( + Tcl_EventSetupProc *setupProc, + /* Function to invoke to figure out what to + * wait for. */ + Tcl_EventCheckProc *checkProc, + /* Function to call after waiting to see what + * happened. */ + ClientData clientData) /* One-word argument to pass to setupProc and + * checkProc. */ +{ + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); + EventSource *sourcePtr = ckalloc(sizeof(EventSource)); + + sourcePtr->setupProc = setupProc; + sourcePtr->checkProc = checkProc; + sourcePtr->clientData = clientData; + sourcePtr->nextPtr = tsdPtr->firstEventSourcePtr; + tsdPtr->firstEventSourcePtr = sourcePtr; +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_DeleteEventSource -- + * + * This function is invoked to delete the source of events given by proc + * and clientData. + * + * Results: + * None. + * + * Side effects: + * The given event source is canceled, so its function will never again + * be called. If no such source exists, nothing happens. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_DeleteEventSource( + Tcl_EventSetupProc *setupProc, + /* Function to invoke to figure out what to + * wait for. */ + Tcl_EventCheckProc *checkProc, + /* Function to call after waiting to see what + * happened. */ + ClientData clientData) /* One-word argument to pass to setupProc and + * checkProc. */ +{ + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); + EventSource *sourcePtr, *prevPtr; + + for (sourcePtr = tsdPtr->firstEventSourcePtr, prevPtr = NULL; + sourcePtr != NULL; + prevPtr = sourcePtr, sourcePtr = sourcePtr->nextPtr) { + if ((sourcePtr->setupProc != setupProc) + || (sourcePtr->checkProc != checkProc) + || (sourcePtr->clientData != clientData)) { + continue; + } + if (prevPtr == NULL) { + tsdPtr->firstEventSourcePtr = sourcePtr->nextPtr; + } else { + prevPtr->nextPtr = sourcePtr->nextPtr; + } + ckfree(sourcePtr); + return; + } +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_QueueEvent -- + * + * Queue an event on the event queue associated with the current thread. + * + * Results: + * None. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_QueueEvent( + 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 = TCL_TSD_INIT(&dataKey); + + QueueEvent(tsdPtr, evPtr, position); +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_ThreadQueueEvent -- + * + * Queue an event on the specified thread's event queue. + * + * Results: + * None. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_ThreadQueueEvent( + 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); + } else { + ckfree(evPtr); + } + 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( + 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 function for each event in the queue and deletes those for + * which the function returns 1. Events for which the function 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( + Tcl_EventDeleteProc *proc, /* The function to call. */ + ClientData clientData) /* The type-specific data. */ +{ + Tcl_Event *evPtr; /* Pointer to the event being examined */ + Tcl_Event *prevPtr; /* Pointer to evPtr's predecessor, or NULL if + * evPtr designates the first event in the + * queue for the thread. */ + Tcl_Event *hold; + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); + + Tcl_MutexLock(&(tsdPtr->queueMutex)); + + /* + * Walk the queue of events for the thread, applying 'proc' to each to + * decide whether to eliminate the event. + */ + + prevPtr = NULL; + evPtr = tsdPtr->firstEventPtr; + while (evPtr != NULL) { + if (proc(evPtr, clientData) == 1) { + /* + * This event should be deleted. Unlink it. + */ + + if (prevPtr == NULL) { + tsdPtr->firstEventPtr = evPtr->nextPtr; + } else { + prevPtr->nextPtr = evPtr->nextPtr; + } + + /* + * Update 'last' and 'marker' events if either has been deleted. + */ + + if (evPtr->nextPtr == NULL) { + tsdPtr->lastEventPtr = prevPtr; + } + if (tsdPtr->markerEventPtr == evPtr) { + tsdPtr->markerEventPtr = prevPtr; + } + + /* + * Delete the event data structure. + */ + + hold = evPtr; + evPtr = evPtr->nextPtr; + ckfree(hold); + } else { + /* + * Event is to be retained. + */ + + 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 function 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( + 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(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 function. 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(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(void) +{ + 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 function. + * + *---------------------------------------------------------------------- + */ + +int +Tcl_SetServiceMode( + 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; + Tcl_ServiceModeHook(mode); + return oldMode; +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_SetMaxBlockTime -- + * + * This function 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( + const 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) { + Tcl_SetTimer(&tsdPtr->blockTime); + } +} + +/* + *---------------------------------------------------------------------- + * + * 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 function 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( + 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(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 function 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(void) +{ + 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(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( + 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) { + Tcl_AlertNotifier(tsdPtr->clientData); + break; + } + } + Tcl_MutexUnlock(&listLock); +} + +/* + * Local Variables: + * mode: c + * c-basic-offset: 4 + * fill-column: 78 + * End: + */ |