Merge commit 'c8bc058c566bbcbcd23e732197d64fecc739008f' as 'tcl8.6'

1 files changed, 1293 insertions, 0 deletions

diff --git a/tcl8.6/generic/tclTimer.c b/tcl8.6/generic/tclTimer.c
new file mode 100644
index 0000000..c10986a
--- /dev/null
+++ b/tcl8.6/generic/tclTimer.c
@@ -0,0 +1,1293 @@
+/*
+ * tclTimer.c --
+ *
+ *	This file provides timer event management facilities for Tcl,
+ *	including the "after" command.
+ *
+ * Copyright (c) 1997 by Sun Microsystems, Inc.
+ *
+ * See the file "license.terms" for information on usage and redistribution of
+ * this file, and for a DISCLAIMER OF ALL WARRANTIES.
+ */
+
+#include "tclInt.h"
+
+/*
+ * For each timer callback that's pending there is one record of the following
+ * type. The normal handlers (created by Tcl_CreateTimerHandler) are chained
+ * together in a list sorted by time (earliest event first).
+ */
+
+typedef struct TimerHandler {
+    Tcl_Time time;		/* When timer is to fire. */
+    Tcl_TimerProc *proc;	/* Function to call. */
+    ClientData clientData;	/* Argument to pass to proc. */
+    Tcl_TimerToken token;	/* Identifies handler so it can be deleted. */
+    struct TimerHandler *nextPtr;
+				/* Next event in queue, or NULL for end of
+				 * queue. */
+} TimerHandler;
+
+/*
+ * The data structure below is used by the "after" command to remember the
+ * command to be executed later. All of the pending "after" commands for an
+ * interpreter are linked together in a list.
+ */
+
+typedef struct AfterInfo {
+    struct AfterAssocData *assocPtr;
+				/* Pointer to the "tclAfter" assocData for the
+				 * interp in which command will be
+				 * executed. */
+    Tcl_Obj *commandPtr;	/* Command to execute. */
+    int id;			/* Integer identifier for command; used to
+				 * cancel it. */
+    Tcl_TimerToken token;	/* Used to cancel the "after" command. NULL
+				 * means that the command is run as an idle
+				 * handler rather than as a timer handler.
+				 * NULL means this is an "after idle" handler
+				 * rather than a timer handler. */
+    struct AfterInfo *nextPtr;	/* Next in list of all "after" commands for
+				 * this interpreter. */
+} AfterInfo;
+
+/*
+ * One of the following structures is associated with each interpreter for
+ * which an "after" command has ever been invoked. A pointer to this structure
+ * is stored in the AssocData for the "tclAfter" key.
+ */
+
+typedef struct AfterAssocData {
+    Tcl_Interp *interp;		/* The interpreter for which this data is
+				 * registered. */
+    AfterInfo *firstAfterPtr;	/* First in list of all "after" commands still
+				 * pending for this interpreter, or NULL if
+				 * none. */
+} AfterAssocData;
+
+/*
+ * There is one of the following structures for each of the handlers declared
+ * in a call to Tcl_DoWhenIdle. All of the currently-active handlers are
+ * linked together into a list.
+ */
+
+typedef struct IdleHandler {
+    Tcl_IdleProc *proc;		/* Function to call. */
+    ClientData clientData;	/* Value to pass to proc. */
+    int generation;		/* Used to distinguish older handlers from
+				 * recently-created ones. */
+    struct IdleHandler *nextPtr;/* Next in list of active handlers. */
+} IdleHandler;
+
+/*
+ * The timer and idle queues are per-thread because they are associated with
+ * the notifier, which is also per-thread.
+ *
+ * All static variables used in this file are collected into a single instance
+ * of the following structure. For multi-threaded implementations, there is
+ * one instance of this structure for each thread.
+ *
+ * Notice that different structures with the same name appear in other files.
+ * The structure defined below is used in this file only.
+ */
+
+typedef struct ThreadSpecificData {
+    TimerHandler *firstTimerHandlerPtr;	/* First event in queue. */
+    int lastTimerId;		/* Timer identifier of most recently created
+				 * timer. */
+    int timerPending;		/* 1 if a timer event is in the queue. */
+    IdleHandler *idleList;	/* First in list of all idle handlers. */
+    IdleHandler *lastIdlePtr;	/* Last in list (or NULL for empty list). */
+    int idleGeneration;		/* Used to fill in the "generation" fields of
+				 * IdleHandler structures. Increments each
+				 * time Tcl_DoOneEvent starts calling idle
+				 * handlers, so that all old handlers can be
+				 * called without calling any of the new ones
+				 * created by old ones. */
+    int afterId;		/* For unique identifiers of after events. */
+} ThreadSpecificData;
+
+static Tcl_ThreadDataKey dataKey;
+
+/*
+ * Helper macros for working with times. TCL_TIME_BEFORE encodes how to write
+ * the ordering relation on (normalized) times, and TCL_TIME_DIFF_MS computes
+ * the number of milliseconds difference between two times. Both macros use
+ * both of their arguments multiple times, so make sure they are cheap and
+ * side-effect free. The "prototypes" for these macros are:
+ *
+ * static int	TCL_TIME_BEFORE(Tcl_Time t1, Tcl_Time t2);
+ * static long	TCL_TIME_DIFF_MS(Tcl_Time t1, Tcl_Time t2);
+ */
+
+#define TCL_TIME_BEFORE(t1, t2) \
+    (((t1).sec<(t2).sec) || ((t1).sec==(t2).sec && (t1).usec<(t2).usec))
+
+#define TCL_TIME_DIFF_MS(t1, t2) \
+    (1000*((Tcl_WideInt)(t1).sec - (Tcl_WideInt)(t2).sec) + \
+	    ((long)(t1).usec - (long)(t2).usec)/1000)
+
+#define TCL_TIME_DIFF_MS_CEILING(t1, t2) \
+    (1000*((Tcl_WideInt)(t1).sec - (Tcl_WideInt)(t2).sec) + \
+	    ((long)(t1).usec - (long)(t2).usec + 999)/1000)
+
+/*
+ * Sleeps under that number of milliseconds don't get double-checked
+ * and are done in exactly one Tcl_Sleep(). This to limit gettimeofday()s.
+ */
+
+#define SLEEP_OFFLOAD_GETTIMEOFDAY 20
+
+/*
+ * The maximum number of milliseconds for each Tcl_Sleep call in AfterDelay.
+ * This is used to limit the maximum lag between interp limit and script
+ * cancellation checks.
+ */
+
+#define TCL_TIME_MAXIMUM_SLICE 500
+
+/*
+ * Prototypes for functions referenced only in this file:
+ */
+
+static void		AfterCleanupProc(ClientData clientData,
+			    Tcl_Interp *interp);
+static int		AfterDelay(Tcl_Interp *interp, Tcl_WideInt ms);
+static void		AfterProc(ClientData clientData);
+static void		FreeAfterPtr(AfterInfo *afterPtr);
+static AfterInfo *	GetAfterEvent(AfterAssocData *assocPtr,
+			    Tcl_Obj *commandPtr);
+static ThreadSpecificData *InitTimer(void);
+static void		TimerExitProc(ClientData clientData);
+static int		TimerHandlerEventProc(Tcl_Event *evPtr, int flags);
+static void		TimerCheckProc(ClientData clientData, int flags);
+static void		TimerSetupProc(ClientData clientData, int flags);
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * InitTimer --
+ *
+ *	This function initializes the timer module.
+ *
+ * Results:
+ *	A pointer to the thread specific data.
+ *
+ * Side effects:
+ *	Registers the idle and timer event sources.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static ThreadSpecificData *
+InitTimer(void)
+{
+    ThreadSpecificData *tsdPtr = TclThreadDataKeyGet(&dataKey);
+
+    if (tsdPtr == NULL) {
+	tsdPtr = TCL_TSD_INIT(&dataKey);
+	Tcl_CreateEventSource(TimerSetupProc, TimerCheckProc, NULL);
+	Tcl_CreateThreadExitHandler(TimerExitProc, NULL);
+    }
+    return tsdPtr;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TimerExitProc --
+ *
+ *	This function is call at exit or unload time to remove the timer and
+ *	idle event sources.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Removes the timer and idle event sources and remaining events.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+TimerExitProc(
+    ClientData clientData)	/* Not used. */
+{
+    ThreadSpecificData *tsdPtr = TclThreadDataKeyGet(&dataKey);
+
+    Tcl_DeleteEventSource(TimerSetupProc, TimerCheckProc, NULL);
+    if (tsdPtr != NULL) {
+	register TimerHandler *timerHandlerPtr;
+
+	timerHandlerPtr = tsdPtr->firstTimerHandlerPtr;
+	while (timerHandlerPtr != NULL) {
+	    tsdPtr->firstTimerHandlerPtr = timerHandlerPtr->nextPtr;
+	    ckfree(timerHandlerPtr);
+	    timerHandlerPtr = tsdPtr->firstTimerHandlerPtr;
+	}
+    }
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * Tcl_CreateTimerHandler --
+ *
+ *	Arrange for a given function to be invoked at a particular time in the
+ *	future.
+ *
+ * Results:
+ *	The return value is a token for the timer event, which may be used to
+ *	delete the event before it fires.
+ *
+ * Side effects:
+ *	When milliseconds have elapsed, proc will be invoked exactly once.
+ *
+ *--------------------------------------------------------------
+ */
+
+Tcl_TimerToken
+Tcl_CreateTimerHandler(
+    int milliseconds,		/* How many milliseconds to wait before
+				 * invoking proc. */
+    Tcl_TimerProc *proc,	/* Function to invoke. */
+    ClientData clientData)	/* Arbitrary data to pass to proc. */
+{
+    Tcl_Time time;
+
+    /*
+     * Compute when the event should fire.
+     */
+
+    Tcl_GetTime(&time);
+    time.sec += milliseconds/1000;
+    time.usec += (milliseconds%1000)*1000;
+    if (time.usec >= 1000000) {
+	time.usec -= 1000000;
+	time.sec += 1;
+    }
+    return TclCreateAbsoluteTimerHandler(&time, proc, clientData);
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * TclCreateAbsoluteTimerHandler --
+ *
+ *	Arrange for a given function to be invoked at a particular time in the
+ *	future.
+ *
+ * Results:
+ *	The return value is a token for the timer event, which may be used to
+ *	delete the event before it fires.
+ *
+ * Side effects:
+ *	When the time in timePtr has been reached, proc will be invoked
+ *	exactly once.
+ *
+ *--------------------------------------------------------------
+ */
+
+Tcl_TimerToken
+TclCreateAbsoluteTimerHandler(
+    Tcl_Time *timePtr,
+    Tcl_TimerProc *proc,
+    ClientData clientData)
+{
+    register TimerHandler *timerHandlerPtr, *tPtr2, *prevPtr;
+    ThreadSpecificData *tsdPtr = InitTimer();
+
+    timerHandlerPtr = ckalloc(sizeof(TimerHandler));
+
+    /*
+     * Fill in fields for the event.
+     */
+
+    memcpy(&timerHandlerPtr->time, timePtr, sizeof(Tcl_Time));
+    timerHandlerPtr->proc = proc;
+    timerHandlerPtr->clientData = clientData;
+    tsdPtr->lastTimerId++;
+    timerHandlerPtr->token = (Tcl_TimerToken) INT2PTR(tsdPtr->lastTimerId);
+
+    /*
+     * Add the event to the queue in the correct position
+     * (ordered by event firing time).
+     */
+
+    for (tPtr2 = tsdPtr->firstTimerHandlerPtr, prevPtr = NULL; tPtr2 != NULL;
+	    prevPtr = tPtr2, tPtr2 = tPtr2->nextPtr) {
+	if (TCL_TIME_BEFORE(timerHandlerPtr->time, tPtr2->time)) {
+	    break;
+	}
+    }
+    timerHandlerPtr->nextPtr = tPtr2;
+    if (prevPtr == NULL) {
+	tsdPtr->firstTimerHandlerPtr = timerHandlerPtr;
+    } else {
+	prevPtr->nextPtr = timerHandlerPtr;
+    }
+
+    TimerSetupProc(NULL, TCL_ALL_EVENTS);
+
+    return timerHandlerPtr->token;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * Tcl_DeleteTimerHandler --
+ *
+ *	Delete a previously-registered timer handler.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Destroy the timer callback identified by TimerToken, so that its
+ *	associated function will not be called. If the callback has already
+ *	fired, or if the given token doesn't exist, then nothing happens.
+ *
+ *--------------------------------------------------------------
+ */
+
+void
+Tcl_DeleteTimerHandler(
+    Tcl_TimerToken token)	/* Result previously returned by
+				 * Tcl_DeleteTimerHandler. */
+{
+    register TimerHandler *timerHandlerPtr, *prevPtr;
+    ThreadSpecificData *tsdPtr = InitTimer();
+
+    if (token == NULL) {
+	return;
+    }
+
+    for (timerHandlerPtr = tsdPtr->firstTimerHandlerPtr, prevPtr = NULL;
+	    timerHandlerPtr != NULL; prevPtr = timerHandlerPtr,
+	    timerHandlerPtr = timerHandlerPtr->nextPtr) {
+	if (timerHandlerPtr->token != token) {
+	    continue;
+	}
+	if (prevPtr == NULL) {
+	    tsdPtr->firstTimerHandlerPtr = timerHandlerPtr->nextPtr;
+	} else {
+	    prevPtr->nextPtr = timerHandlerPtr->nextPtr;
+	}
+	ckfree(timerHandlerPtr);
+	return;
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TimerSetupProc --
+ *
+ *	This function is called by Tcl_DoOneEvent to setup the timer event
+ *	source for before blocking. This routine checks both the idle and
+ *	after timer lists.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	May update the maximum notifier block time.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+TimerSetupProc(
+    ClientData data,		/* Not used. */
+    int flags)			/* Event flags as passed to Tcl_DoOneEvent. */
+{
+    Tcl_Time blockTime;
+    ThreadSpecificData *tsdPtr = InitTimer();
+
+    if (((flags & TCL_IDLE_EVENTS) && tsdPtr->idleList)
+	    || ((flags & TCL_TIMER_EVENTS) && tsdPtr->timerPending)) {
+	/*
+	 * There is an idle handler or a pending timer event, so just poll.
+	 */
+
+	blockTime.sec = 0;
+	blockTime.usec = 0;
+    } else if ((flags & TCL_TIMER_EVENTS) && tsdPtr->firstTimerHandlerPtr) {
+	/*
+	 * Compute the timeout for the next timer on the list.
+	 */
+
+	Tcl_GetTime(&blockTime);
+	blockTime.sec = tsdPtr->firstTimerHandlerPtr->time.sec - blockTime.sec;
+	blockTime.usec = tsdPtr->firstTimerHandlerPtr->time.usec -
+		blockTime.usec;
+	if (blockTime.usec < 0) {
+	    blockTime.sec -= 1;
+	    blockTime.usec += 1000000;
+	}
+	if (blockTime.sec < 0) {
+	    blockTime.sec = 0;
+	    blockTime.usec = 0;
+	}
+    } else {
+	return;
+    }
+
+    Tcl_SetMaxBlockTime(&blockTime);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TimerCheckProc --
+ *
+ *	This function is called by Tcl_DoOneEvent to check the timer event
+ *	source for events. This routine checks both the idle and after timer
+ *	lists.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	May queue an event and update the maximum notifier block time.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+TimerCheckProc(
+    ClientData data,		/* Not used. */
+    int flags)			/* Event flags as passed to Tcl_DoOneEvent. */
+{
+    Tcl_Event *timerEvPtr;
+    Tcl_Time blockTime;
+    ThreadSpecificData *tsdPtr = InitTimer();
+
+    if ((flags & TCL_TIMER_EVENTS) && tsdPtr->firstTimerHandlerPtr) {
+	/*
+	 * Compute the timeout for the next timer on the list.
+	 */
+
+	Tcl_GetTime(&blockTime);
+	blockTime.sec = tsdPtr->firstTimerHandlerPtr->time.sec - blockTime.sec;
+	blockTime.usec = tsdPtr->firstTimerHandlerPtr->time.usec -
+		blockTime.usec;
+	if (blockTime.usec < 0) {
+	    blockTime.sec -= 1;
+	    blockTime.usec += 1000000;
+	}
+	if (blockTime.sec < 0) {
+	    blockTime.sec = 0;
+	    blockTime.usec = 0;
+	}
+
+	/*
+	 * If the first timer has expired, stick an event on the queue.
+	 */
+
+	if (blockTime.sec == 0 && blockTime.usec == 0 &&
+		!tsdPtr->timerPending) {
+	    tsdPtr->timerPending = 1;
+	    timerEvPtr = ckalloc(sizeof(Tcl_Event));
+	    timerEvPtr->proc = TimerHandlerEventProc;
+	    Tcl_QueueEvent(timerEvPtr, TCL_QUEUE_TAIL);
+	}
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TimerHandlerEventProc --
+ *
+ *	This function is called by Tcl_ServiceEvent when a timer event reaches
+ *	the front of the event queue. This function handles the event by
+ *	invoking the callbacks for all timers that are ready.
+ *
+ * Results:
+ *	Returns 1 if the event was handled, meaning it should be removed from
+ *	the queue. Returns 0 if the event was not handled, meaning it should
+ *	stay on the queue. The only time the event isn't handled is if the
+ *	TCL_TIMER_EVENTS flag bit isn't set.
+ *
+ * Side effects:
+ *	Whatever the timer handler callback functions do.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+TimerHandlerEventProc(
+    Tcl_Event *evPtr,		/* Event to service. */
+    int flags)			/* Flags that indicate what events to handle,
+				 * such as TCL_FILE_EVENTS. */
+{
+    TimerHandler *timerHandlerPtr, **nextPtrPtr;
+    Tcl_Time time;
+    int currentTimerId;
+    ThreadSpecificData *tsdPtr = InitTimer();
+
+    /*
+     * Do nothing if timers aren't enabled. This leaves the event on the
+     * queue, so we will get to it as soon as ServiceEvents() is called with
+     * timers enabled.
+     */
+
+    if (!(flags & TCL_TIMER_EVENTS)) {
+	return 0;
+    }
+
+    /*
+     * The code below is trickier than it may look, for the following reasons:
+     *
+     * 1. New handlers can get added to the list while the current one is
+     *	  being processed. If new ones get added, we don't want to process
+     *	  them during this pass through the list to avoid starving other event
+     *	  sources. This is implemented using the token number in the handler:
+     *	  new handlers will have a newer token than any of the ones currently
+     *	  on the list.
+     * 2. The handler can call Tcl_DoOneEvent, so we have to remove the
+     *	  handler from the list before calling it. Otherwise an infinite loop
+     *	  could result.
+     * 3. Tcl_DeleteTimerHandler can be called to remove an element from the
+     *	  list while a handler is executing, so the list could change
+     *	  structure during the call.
+     * 4. Because we only fetch the current time before entering the loop, the
+     *	  only way a new timer will even be considered runnable is if its
+     *	  expiration time is within the same millisecond as the current time.
+     *	  This is fairly likely on Windows, since it has a course granularity
+     *	  clock. Since timers are placed on the queue in time order with the
+     *	  most recently created handler appearing after earlier ones with the
+     *	  same expiration time, we don't have to worry about newer generation
+     *	  timers appearing before later ones.
+     */
+
+    tsdPtr->timerPending = 0;
+    currentTimerId = tsdPtr->lastTimerId;
+    Tcl_GetTime(&time);
+    while (1) {
+	nextPtrPtr = &tsdPtr->firstTimerHandlerPtr;
+	timerHandlerPtr = tsdPtr->firstTimerHandlerPtr;
+	if (timerHandlerPtr == NULL) {
+	    break;
+	}
+
+	if (TCL_TIME_BEFORE(time, timerHandlerPtr->time)) {
+	    break;
+	}
+
+	/*
+	 * Bail out if the next timer is of a newer generation.
+	 */
+
+	if ((currentTimerId - PTR2INT(timerHandlerPtr->token)) < 0) {
+	    break;
+	}
+
+	/*
+	 * Remove the handler from the queue before invoking it, to avoid
+	 * potential reentrancy problems.
+	 */
+
+	*nextPtrPtr = timerHandlerPtr->nextPtr;
+	timerHandlerPtr->proc(timerHandlerPtr->clientData);
+	ckfree(timerHandlerPtr);
+    }
+    TimerSetupProc(NULL, TCL_TIMER_EVENTS);
+    return 1;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * Tcl_DoWhenIdle --
+ *
+ *	Arrange for proc to be invoked the next time the system is idle (i.e.,
+ *	just before the next time that Tcl_DoOneEvent would have to wait for
+ *	something to happen).
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Proc will eventually be called, with clientData as argument. See the
+ *	manual entry for details.
+ *
+ *--------------------------------------------------------------
+ */
+
+void
+Tcl_DoWhenIdle(
+    Tcl_IdleProc *proc,		/* Function to invoke. */
+    ClientData clientData)	/* Arbitrary value to pass to proc. */
+{
+    register IdleHandler *idlePtr;
+    Tcl_Time blockTime;
+    ThreadSpecificData *tsdPtr = InitTimer();
+
+    idlePtr = ckalloc(sizeof(IdleHandler));
+    idlePtr->proc = proc;
+    idlePtr->clientData = clientData;
+    idlePtr->generation = tsdPtr->idleGeneration;
+    idlePtr->nextPtr = NULL;
+    if (tsdPtr->lastIdlePtr == NULL) {
+	tsdPtr->idleList = idlePtr;
+    } else {
+	tsdPtr->lastIdlePtr->nextPtr = idlePtr;
+    }
+    tsdPtr->lastIdlePtr = idlePtr;
+
+    blockTime.sec = 0;
+    blockTime.usec = 0;
+    Tcl_SetMaxBlockTime(&blockTime);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_CancelIdleCall --
+ *
+ *	If there are any when-idle calls requested to a given function with
+ *	given clientData, cancel all of them.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	If the proc/clientData combination were on the when-idle list, they
+ *	are removed so that they will never be called.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_CancelIdleCall(
+    Tcl_IdleProc *proc,		/* Function that was previously registered. */
+    ClientData clientData)	/* Arbitrary value to pass to proc. */
+{
+    register IdleHandler *idlePtr, *prevPtr;
+    IdleHandler *nextPtr;
+    ThreadSpecificData *tsdPtr = InitTimer();
+
+    for (prevPtr = NULL, idlePtr = tsdPtr->idleList; idlePtr != NULL;
+	    prevPtr = idlePtr, idlePtr = idlePtr->nextPtr) {
+	while ((idlePtr->proc == proc)
+		&& (idlePtr->clientData == clientData)) {
+	    nextPtr = idlePtr->nextPtr;
+	    ckfree(idlePtr);
+	    idlePtr = nextPtr;
+	    if (prevPtr == NULL) {
+		tsdPtr->idleList = idlePtr;
+	    } else {
+		prevPtr->nextPtr = idlePtr;
+	    }
+	    if (idlePtr == NULL) {
+		tsdPtr->lastIdlePtr = prevPtr;
+		return;
+	    }
+	}
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclServiceIdle --
+ *
+ *	This function is invoked by the notifier when it becomes idle. It will
+ *	invoke all idle handlers that are present at the time the call is
+ *	invoked, but not those added during idle processing.
+ *
+ * Results:
+ *	The return value is 1 if TclServiceIdle found something to do,
+ *	otherwise return value is 0.
+ *
+ * Side effects:
+ *	Invokes all pending idle handlers.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TclServiceIdle(void)
+{
+    IdleHandler *idlePtr;
+    int oldGeneration;
+    Tcl_Time blockTime;
+    ThreadSpecificData *tsdPtr = InitTimer();
+
+    if (tsdPtr->idleList == NULL) {
+	return 0;
+    }
+
+    oldGeneration = tsdPtr->idleGeneration;
+    tsdPtr->idleGeneration++;
+
+    /*
+     * The code below is trickier than it may look, for the following reasons:
+     *
+     * 1. New handlers can get added to the list while the current one is
+     *	  being processed. If new ones get added, we don't want to process
+     *	  them during this pass through the list (want to check for other work
+     *	  to do first). This is implemented using the generation number in the
+     *	  handler: new handlers will have a different generation than any of
+     *	  the ones currently on the list.
+     * 2. The handler can call Tcl_DoOneEvent, so we have to remove the
+     *	  handler from the list before calling it. Otherwise an infinite loop
+     *	  could result.
+     * 3. Tcl_CancelIdleCall can be called to remove an element from the list
+     *	  while a handler is executing, so the list could change structure
+     *	  during the call.
+     */
+
+    for (idlePtr = tsdPtr->idleList;
+	    ((idlePtr != NULL)
+		    && ((oldGeneration - idlePtr->generation) >= 0));
+	    idlePtr = tsdPtr->idleList) {
+	tsdPtr->idleList = idlePtr->nextPtr;
+	if (tsdPtr->idleList == NULL) {
+	    tsdPtr->lastIdlePtr = NULL;
+	}
+	idlePtr->proc(idlePtr->clientData);
+	ckfree(idlePtr);
+    }
+    if (tsdPtr->idleList) {
+	blockTime.sec = 0;
+	blockTime.usec = 0;
+	Tcl_SetMaxBlockTime(&blockTime);
+    }
+    return 1;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_AfterObjCmd --
+ *
+ *	This function is invoked to process the "after" Tcl command. See the
+ *	user documentation for details on what it does.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	See the user documentation.
+ *
+ *----------------------------------------------------------------------
+ */
+
+	/* ARGSUSED */
+int
+Tcl_AfterObjCmd(
+    ClientData clientData,	/* Unused */
+    Tcl_Interp *interp,		/* Current interpreter. */
+    int objc,			/* Number of arguments. */
+    Tcl_Obj *const objv[])	/* Argument objects. */
+{
+    Tcl_WideInt ms = 0;		/* Number of milliseconds to wait */
+    Tcl_Time wakeup;
+    AfterInfo *afterPtr;
+    AfterAssocData *assocPtr;
+    int length;
+    int index;
+    static const char *const afterSubCmds[] = {
+	"cancel", "idle", "info", NULL
+    };
+    enum afterSubCmds {AFTER_CANCEL, AFTER_IDLE, AFTER_INFO};
+    ThreadSpecificData *tsdPtr = InitTimer();
+
+    if (objc < 2) {
+	Tcl_WrongNumArgs(interp, 1, objv, "option ?arg ...?");
+	return TCL_ERROR;
+    }
+
+    /*
+     * Create the "after" information associated for this interpreter, if it
+     * doesn't already exist.
+     */
+
+    assocPtr = Tcl_GetAssocData(interp, "tclAfter", NULL);
+    if (assocPtr == NULL) {
+	assocPtr = ckalloc(sizeof(AfterAssocData));
+	assocPtr->interp = interp;
+	assocPtr->firstAfterPtr = NULL;
+	Tcl_SetAssocData(interp, "tclAfter", AfterCleanupProc, assocPtr);
+    }
+
+    /*
+     * First lets see if the command was passed a number as the first argument.
+     */
+
+    if (objv[1]->typePtr == &tclIntType
+#ifndef TCL_WIDE_INT_IS_LONG
+	    || objv[1]->typePtr == &tclWideIntType
+#endif
+	    || objv[1]->typePtr == &tclBignumType
+	    || (Tcl_GetIndexFromObj(NULL, objv[1], afterSubCmds, "", 0,
+		    &index) != TCL_OK)) {
+	index = -1;
+	if (Tcl_GetWideIntFromObj(NULL, objv[1], &ms) != TCL_OK) {
+            const char *arg = Tcl_GetString(objv[1]);
+
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                    "bad argument \"%s\": must be"
+                    " cancel, idle, info, or an integer", arg));
+            Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "INDEX", "argument",
+                    arg, NULL);
+	    return TCL_ERROR;
+	}
+    }
+
+    /*
+     * At this point, either index = -1 and ms contains the number of ms
+     * to wait, or else index is the index of a subcommand.
+     */
+
+    switch (index) {
+    case -1: {
+	if (ms < 0) {
+	    ms = 0;
+	}
+	if (objc == 2) {
+	    return AfterDelay(interp, ms);
+	}
+	afterPtr = ckalloc(sizeof(AfterInfo));
+	afterPtr->assocPtr = assocPtr;
+	if (objc == 3) {
+	    afterPtr->commandPtr = objv[2];
+	} else {
+	    afterPtr->commandPtr = Tcl_ConcatObj(objc-2, objv+2);
+	}
+	Tcl_IncrRefCount(afterPtr->commandPtr);
+
+	/*
+	 * The variable below is used to generate unique identifiers for after
+	 * commands. This id can wrap around, which can potentially cause
+	 * problems. However, there are not likely to be problems in practice,
+	 * because after commands can only be requested to about a month in
+	 * the future, and wrap-around is unlikely to occur in less than about
+	 * 1-10 years. Thus it's unlikely that any old ids will still be
+	 * around when wrap-around occurs.
+	 */
+
+	afterPtr->id = tsdPtr->afterId;
+	tsdPtr->afterId += 1;
+	Tcl_GetTime(&wakeup);
+	wakeup.sec += (long)(ms / 1000);
+	wakeup.usec += ((long)(ms % 1000)) * 1000;
+	if (wakeup.usec > 1000000) {
+	    wakeup.sec++;
+	    wakeup.usec -= 1000000;
+	}
+	afterPtr->token = TclCreateAbsoluteTimerHandler(&wakeup,
+		AfterProc, afterPtr);
+	afterPtr->nextPtr = assocPtr->firstAfterPtr;
+	assocPtr->firstAfterPtr = afterPtr;
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf("after#%d", afterPtr->id));
+	return TCL_OK;
+    }
+    case AFTER_CANCEL: {
+	Tcl_Obj *commandPtr;
+	const char *command, *tempCommand;
+	int tempLength;
+
+	if (objc < 3) {
+	    Tcl_WrongNumArgs(interp, 2, objv, "id|command");
+	    return TCL_ERROR;
+	}
+	if (objc == 3) {
+	    commandPtr = objv[2];
+	} else {
+	    commandPtr = Tcl_ConcatObj(objc-2, objv+2);;
+	}
+	command = Tcl_GetStringFromObj(commandPtr, &length);
+	for (afterPtr = assocPtr->firstAfterPtr;  afterPtr != NULL;
+		afterPtr = afterPtr->nextPtr) {
+	    tempCommand = Tcl_GetStringFromObj(afterPtr->commandPtr,
+		    &tempLength);
+	    if ((length == tempLength)
+		    && !memcmp(command, tempCommand, (unsigned) length)) {
+		break;
+	    }
+	}
+	if (afterPtr == NULL) {
+	    afterPtr = GetAfterEvent(assocPtr, commandPtr);
+	}
+	if (objc != 3) {
+	    Tcl_DecrRefCount(commandPtr);
+	}
+	if (afterPtr != NULL) {
+	    if (afterPtr->token != NULL) {
+		Tcl_DeleteTimerHandler(afterPtr->token);
+	    } else {
+		Tcl_CancelIdleCall(AfterProc, afterPtr);
+	    }
+	    FreeAfterPtr(afterPtr);
+	}
+	break;
+    }
+    case AFTER_IDLE:
+	if (objc < 3) {
+	    Tcl_WrongNumArgs(interp, 2, objv, "script ?script ...?");
+	    return TCL_ERROR;
+	}
+	afterPtr = ckalloc(sizeof(AfterInfo));
+	afterPtr->assocPtr = assocPtr;
+	if (objc == 3) {
+	    afterPtr->commandPtr = objv[2];
+	} else {
+	    afterPtr->commandPtr = Tcl_ConcatObj(objc-2, objv+2);
+	}
+	Tcl_IncrRefCount(afterPtr->commandPtr);
+	afterPtr->id = tsdPtr->afterId;
+	tsdPtr->afterId += 1;
+	afterPtr->token = NULL;
+	afterPtr->nextPtr = assocPtr->firstAfterPtr;
+	assocPtr->firstAfterPtr = afterPtr;
+	Tcl_DoWhenIdle(AfterProc, afterPtr);
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf("after#%d", afterPtr->id));
+	break;
+    case AFTER_INFO:
+	if (objc == 2) {
+            Tcl_Obj *resultObj = Tcl_NewObj();
+
+	    for (afterPtr = assocPtr->firstAfterPtr; afterPtr != NULL;
+		    afterPtr = afterPtr->nextPtr) {
+		if (assocPtr->interp == interp) {
+                    Tcl_ListObjAppendElement(NULL, resultObj, Tcl_ObjPrintf(
+                            "after#%d", afterPtr->id));
+		}
+	    }
+            Tcl_SetObjResult(interp, resultObj);
+	    return TCL_OK;
+	}
+	if (objc != 3) {
+	    Tcl_WrongNumArgs(interp, 2, objv, "?id?");
+	    return TCL_ERROR;
+	}
+	afterPtr = GetAfterEvent(assocPtr, objv[2]);
+	if (afterPtr == NULL) {
+            const char *eventStr = TclGetString(objv[2]);
+
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+                    "event \"%s\" doesn't exist", eventStr));
+            Tcl_SetErrorCode(interp, "TCL","LOOKUP","EVENT", eventStr, NULL);
+	    return TCL_ERROR;
+	} else {
+            Tcl_Obj *resultListPtr = Tcl_NewObj();
+
+            Tcl_ListObjAppendElement(interp, resultListPtr,
+                    afterPtr->commandPtr);
+            Tcl_ListObjAppendElement(interp, resultListPtr, Tcl_NewStringObj(
+		    (afterPtr->token == NULL) ? "idle" : "timer", -1));
+            Tcl_SetObjResult(interp, resultListPtr);
+        }
+	break;
+    default:
+	Tcl_Panic("Tcl_AfterObjCmd: bad subcommand index to afterSubCmds");
+    }
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * AfterDelay --
+ *
+ *	Implements the blocking delay behaviour of [after $time]. Tricky
+ *	because it has to take into account any time limit that has been set.
+ *
+ * Results:
+ *	Standard Tcl result code (with error set if an error occurred due to a
+ *	time limit being exceeded or being canceled).
+ *
+ * Side effects:
+ *	May adjust the time limit granularity marker.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+AfterDelay(
+    Tcl_Interp *interp,
+    Tcl_WideInt ms)
+{
+    Interp *iPtr = (Interp *) interp;
+
+    Tcl_Time endTime, now;
+    Tcl_WideInt diff;
+
+    Tcl_GetTime(&now);
+    endTime = now;
+    endTime.sec += (long)(ms/1000);
+    endTime.usec += ((int)(ms%1000))*1000;
+    if (endTime.usec >= 1000000) {
+	endTime.sec++;
+	endTime.usec -= 1000000;
+    }
+
+    do {
+	if (Tcl_AsyncReady()) {
+	    if (Tcl_AsyncInvoke(interp, TCL_OK) != TCL_OK) {
+		return TCL_ERROR;
+	    }
+	}
+	if (Tcl_Canceled(interp, TCL_LEAVE_ERR_MSG) == TCL_ERROR) {
+	    return TCL_ERROR;
+	}
+	if (iPtr->limit.timeEvent != NULL
+		&& TCL_TIME_BEFORE(iPtr->limit.time, now)) {
+	    iPtr->limit.granularityTicker = 0;
+	    if (Tcl_LimitCheck(interp) != TCL_OK) {
+		return TCL_ERROR;
+	    }
+	}
+	if (iPtr->limit.timeEvent == NULL
+		|| TCL_TIME_BEFORE(endTime, iPtr->limit.time)) {
+	    diff = TCL_TIME_DIFF_MS_CEILING(endTime, now);
+#ifndef TCL_WIDE_INT_IS_LONG
+	    if (diff > LONG_MAX) {
+		diff = LONG_MAX;
+	    }
+#endif
+	    if (diff > TCL_TIME_MAXIMUM_SLICE) {
+		diff = TCL_TIME_MAXIMUM_SLICE;
+	    }
+            if (diff == 0 && TCL_TIME_BEFORE(now, endTime)) diff = 1;
+	    if (diff > 0) {
+		Tcl_Sleep((long) diff);
+                if (diff < SLEEP_OFFLOAD_GETTIMEOFDAY) break;
+	    } else break;
+	} else {
+	    diff = TCL_TIME_DIFF_MS(iPtr->limit.time, now);
+#ifndef TCL_WIDE_INT_IS_LONG
+	    if (diff > LONG_MAX) {
+		diff = LONG_MAX;
+	    }
+#endif
+	    if (diff > TCL_TIME_MAXIMUM_SLICE) {
+		diff = TCL_TIME_MAXIMUM_SLICE;
+	    }
+	    if (diff > 0) {
+		Tcl_Sleep((long) diff);
+	    }
+	    if (Tcl_AsyncReady()) {
+		if (Tcl_AsyncInvoke(interp, TCL_OK) != TCL_OK) {
+		    return TCL_ERROR;
+		}
+	    }
+	    if (Tcl_Canceled(interp, TCL_LEAVE_ERR_MSG) == TCL_ERROR) {
+		return TCL_ERROR;
+	    }
+	    if (Tcl_LimitCheck(interp) != TCL_OK) {
+		return TCL_ERROR;
+	    }
+	}
+        Tcl_GetTime(&now);
+    } while (TCL_TIME_BEFORE(now, endTime));
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * GetAfterEvent --
+ *
+ *	This function parses an "after" id such as "after#4" and returns a
+ *	pointer to the AfterInfo structure.
+ *
+ * Results:
+ *	The return value is either a pointer to an AfterInfo structure, if one
+ *	is found that corresponds to "cmdString" and is for interp, or NULL if
+ *	no corresponding after event can be found.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static AfterInfo *
+GetAfterEvent(
+    AfterAssocData *assocPtr,	/* Points to "after"-related information for
+				 * this interpreter. */
+    Tcl_Obj *commandPtr)
+{
+    const char *cmdString;	/* Textual identifier for after event, such as
+				 * "after#6". */
+    AfterInfo *afterPtr;
+    int id;
+    char *end;
+
+    cmdString = TclGetString(commandPtr);
+    if (strncmp(cmdString, "after#", 6) != 0) {
+	return NULL;
+    }
+    cmdString += 6;
+    id = strtoul(cmdString, &end, 10);
+    if ((end == cmdString) || (*end != 0)) {
+	return NULL;
+    }
+    for (afterPtr = assocPtr->firstAfterPtr; afterPtr != NULL;
+	    afterPtr = afterPtr->nextPtr) {
+	if (afterPtr->id == id) {
+	    return afterPtr;
+	}
+    }
+    return NULL;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * AfterProc --
+ *
+ *	Timer callback to execute commands registered with the "after"
+ *	command.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Executes whatever command was specified. If the command returns an
+ *	error, then the command "bgerror" is invoked to process the error; if
+ *	bgerror fails then information about the error is output on stderr.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+AfterProc(
+    ClientData clientData)	/* Describes command to execute. */
+{
+    AfterInfo *afterPtr = clientData;
+    AfterAssocData *assocPtr = afterPtr->assocPtr;
+    AfterInfo *prevPtr;
+    int result;
+    Tcl_Interp *interp;
+
+    /*
+     * First remove the callback from our list of callbacks; otherwise someone
+     * could delete the callback while it's being executed, which could cause
+     * a core dump.
+     */
+
+    if (assocPtr->firstAfterPtr == afterPtr) {
+	assocPtr->firstAfterPtr = afterPtr->nextPtr;
+    } else {
+	for (prevPtr = assocPtr->firstAfterPtr; prevPtr->nextPtr != afterPtr;
+		prevPtr = prevPtr->nextPtr) {
+	    /* Empty loop body. */
+	}
+	prevPtr->nextPtr = afterPtr->nextPtr;
+    }
+
+    /*
+     * Execute the callback.
+     */
+
+    interp = assocPtr->interp;
+    Tcl_Preserve(interp);
+    result = Tcl_EvalObjEx(interp, afterPtr->commandPtr, TCL_EVAL_GLOBAL);
+    if (result != TCL_OK) {
+	Tcl_AddErrorInfo(interp, "\n    (\"after\" script)");
+	Tcl_BackgroundException(interp, result);
+    }
+    Tcl_Release(interp);
+
+    /*
+     * Free the memory for the callback.
+     */
+
+    Tcl_DecrRefCount(afterPtr->commandPtr);
+    ckfree(afterPtr);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FreeAfterPtr --
+ *
+ *	This function removes an "after" command from the list of those that
+ *	are pending and frees its resources. This function does *not* cancel
+ *	the timer handler; if that's needed, the caller must do it.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The memory associated with afterPtr is released.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+FreeAfterPtr(
+    AfterInfo *afterPtr)		/* Command to be deleted. */
+{
+    AfterInfo *prevPtr;
+    AfterAssocData *assocPtr = afterPtr->assocPtr;
+
+    if (assocPtr->firstAfterPtr == afterPtr) {
+	assocPtr->firstAfterPtr = afterPtr->nextPtr;
+    } else {
+	for (prevPtr = assocPtr->firstAfterPtr; prevPtr->nextPtr != afterPtr;
+		prevPtr = prevPtr->nextPtr) {
+	    /* Empty loop body. */
+	}
+	prevPtr->nextPtr = afterPtr->nextPtr;
+    }
+    Tcl_DecrRefCount(afterPtr->commandPtr);
+    ckfree(afterPtr);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * AfterCleanupProc --
+ *
+ *	This function is invoked whenever an interpreter is deleted
+ *	to cleanup the AssocData for "tclAfter".
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	After commands are removed.
+ *
+ *----------------------------------------------------------------------
+ */
+
+	/* ARGSUSED */
+static void
+AfterCleanupProc(
+    ClientData clientData,	/* Points to AfterAssocData for the
+				 * interpreter. */
+    Tcl_Interp *interp)		/* Interpreter that is being deleted. */
+{
+    AfterAssocData *assocPtr = clientData;
+    AfterInfo *afterPtr;
+
+    while (assocPtr->firstAfterPtr != NULL) {
+	afterPtr = assocPtr->firstAfterPtr;
+	assocPtr->firstAfterPtr = afterPtr->nextPtr;
+	if (afterPtr->token != NULL) {
+	    Tcl_DeleteTimerHandler(afterPtr->token);
+	} else {
+	    Tcl_CancelIdleCall(AfterProc, afterPtr);
+	}
+	Tcl_DecrRefCount(afterPtr->commandPtr);
+	ckfree(afterPtr);
+    }
+    ckfree(assocPtr);
+}
+
+/*
+ * Local Variables:
+ * mode: c
+ * c-basic-offset: 4
+ * fill-column: 78
+ * tab-width: 8
+ * indent-tabs-mode: nil
+ * End:
+ */