579 lines
16 KiB
C
579 lines
16 KiB
C
|
/*
|
|||
|
* tclNotify.c --
|
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|
*
|
|||
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* This file provides the parts of the Tcl event notifier that are
|
|||
|
* the same on all platforms, plus a few other parts that are used
|
|||
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* on more than one platform but not all.
|
|||
|
*
|
|||
|
* The notifier is the lowest-level part of the event system. It
|
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* manages an event queue that holds Tcl_Event structures and a list
|
|||
|
* of event sources that can add events to the queue. It also
|
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* contains the procedure Tcl_DoOneEvent that invokes the event
|
|||
|
* sources and blocks to wait for new events, but Tcl_DoOneEvent
|
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* is in the platform-specific part of the notifier (in files like
|
|||
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* tclUnixNotify.c).
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*
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* Copyright (c) 1995 Sun Microsystems, Inc.
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*
|
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* See the file "license.terms" for information on usage and redistribution
|
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* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
|
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*
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|||
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* SCCS: @(#) tclNotify.c 1.6 96/02/29 09:20:10
|
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|
*/
|
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|
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#include "tclInt.h"
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#include "tclPort.h"
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/*
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* The following variable records the address of the first event
|
|||
|
* source in the list of all event sources for the application.
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* This variable is accessed by the notifier to traverse the list
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* and invoke each event source.
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*/
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TclEventSource *tclFirstEventSourcePtr = NULL;
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/*
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* The following variables indicate how long to block in the event
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|||
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* notifier the next time it blocks (default: block forever).
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*/
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static int blockTimeSet = 0; /* 0 means there is no maximum block
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* time: block forever. */
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static Tcl_Time blockTime; /* If blockTimeSet is 1, gives the
|
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|
* maximum elapsed time for the next block. */
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|
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/*
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* The following variables keep track of the event queue. In addition
|
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* to the first (next to be serviced) and last events in the queue,
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* we keep track of a "marker" event. This provides a simple priority
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* mechanism whereby events can be inserted at the front of the queue
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* but behind all other high-priority events already in the queue (this
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* is used for things like a sequence of Enter and Leave events generated
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* during a grab in Tk).
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*/
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static Tcl_Event *firstEventPtr = NULL;
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/* First pending event, or NULL if none. */
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static Tcl_Event *lastEventPtr = NULL;
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/* Last pending event, or NULL if none. */
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static Tcl_Event *markerEventPtr = NULL;
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/* Last high-priority event in queue, or
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* NULL if none. */
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/*
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* Prototypes for procedures used only in this file:
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*/
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static int ServiceEvent _ANSI_ARGS_((int flags));
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/*
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*----------------------------------------------------------------------
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*
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* Tcl_CreateEventSource --
|
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*
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* This procedure is invoked to create a new source of events.
|
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* The source is identified by a procedure that gets invoked
|
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* during Tcl_DoOneEvent to check for events on that source
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* and queue them.
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*
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*
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* Results:
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|
* None.
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|||
|
*
|
|||
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* Side effects:
|
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* SetupProc and checkProc will be invoked each time that Tcl_DoOneEvent
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* runs out of things to do. SetupProc will be invoked before
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* Tcl_DoOneEvent calls select or whatever else it uses to wait
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* for events. SetupProc typically calls functions like Tcl_WatchFile
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* or Tcl_SetMaxBlockTime to indicate what to wait for.
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*
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* CheckProc is called after select or whatever operation was actually
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* used to wait. It figures out whether anything interesting actually
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* happened (e.g. by calling Tcl_FileReady), and then calls
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* Tcl_QueueEvent to queue any events that are ready.
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*
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* Each of these procedures is passed two arguments, e.g.
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* (*checkProc)(ClientData clientData, int flags));
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* ClientData is the same as the clientData argument here, and flags
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* is a combination of things like TCL_FILE_EVENTS that indicates
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* what events are of interest: setupProc and checkProc use flags
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* to figure out whether their events are relevant or not.
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*
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*----------------------------------------------------------------------
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*/
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void
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Tcl_CreateEventSource(setupProc, checkProc, clientData)
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Tcl_EventSetupProc *setupProc; /* Procedure to invoke to figure out
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* what to wait for. */
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Tcl_EventCheckProc *checkProc; /* Procedure to call after waiting
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* to see what happened. */
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ClientData clientData; /* One-word argument to pass to
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* setupProc and checkProc. */
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{
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TclEventSource *sourcePtr;
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sourcePtr = (TclEventSource *) ckalloc(sizeof(TclEventSource));
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sourcePtr->setupProc = setupProc;
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sourcePtr->checkProc = checkProc;
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sourcePtr->clientData = clientData;
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sourcePtr->nextPtr = tclFirstEventSourcePtr;
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tclFirstEventSourcePtr = sourcePtr;
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}
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/*
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*----------------------------------------------------------------------
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*
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* Tcl_DeleteEventSource --
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*
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* This procedure is invoked to delete the source of events
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* given by proc and clientData.
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*
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* Results:
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* None.
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*
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* Side effects:
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* The given event source is cancelled, so its procedure will
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* never again be called. If no such source exists, nothing
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* happens.
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*
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*----------------------------------------------------------------------
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*/
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void
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Tcl_DeleteEventSource(setupProc, checkProc, clientData)
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Tcl_EventSetupProc *setupProc; /* Procedure to invoke to figure out
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* what to wait for. */
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Tcl_EventCheckProc *checkProc; /* Procedure to call after waiting
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* to see what happened. */
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ClientData clientData; /* One-word argument to pass to
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* setupProc and checkProc. */
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{
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TclEventSource *sourcePtr, *prevPtr;
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for (sourcePtr = tclFirstEventSourcePtr, prevPtr = NULL;
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sourcePtr != NULL;
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prevPtr = sourcePtr, sourcePtr = sourcePtr->nextPtr) {
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if ((sourcePtr->setupProc != setupProc)
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|| (sourcePtr->checkProc != checkProc)
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|| (sourcePtr->clientData != clientData)) {
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continue;
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}
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if (prevPtr == NULL) {
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tclFirstEventSourcePtr = sourcePtr->nextPtr;
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} else {
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|
prevPtr->nextPtr = sourcePtr->nextPtr;
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}
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ckfree((char *) sourcePtr);
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return;
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|
}
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|||
|
}
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|
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|||
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/*
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|||
|
*----------------------------------------------------------------------
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*
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|
* Tcl_QueueEvent --
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*
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* Insert an event into the Tk event queue at one of three
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* positions: the head, the tail, or before a floating marker.
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* Events inserted before the marker will be processed in
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* first-in-first-out order, but before any events inserted at
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* the tail of the queue. Events inserted at the head of the
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* queue will be processed in last-in-first-out order.
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*
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* Results:
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|||
|
* None.
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|||
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*
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|||
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* Side effects:
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|||
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* None.
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|||
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*
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*----------------------------------------------------------------------
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*/
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void
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Tcl_QueueEvent(evPtr, position)
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Tcl_Event* evPtr; /* Event to add to queue. The storage
|
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|
* space must have been allocated the caller
|
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* with malloc (ckalloc), and it becomes
|
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* the property of the event queue. It
|
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|
* will be freed after the event has been
|
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* handled. */
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Tcl_QueuePosition position; /* One of TCL_QUEUE_TAIL, TCL_QUEUE_HEAD,
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* TCL_QUEUE_MARK. */
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{
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if (position == TCL_QUEUE_TAIL) {
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/*
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* Append the event on the end of the queue.
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*/
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evPtr->nextPtr = NULL;
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if (firstEventPtr == NULL) {
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firstEventPtr = evPtr;
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} else {
|
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lastEventPtr->nextPtr = evPtr;
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|
}
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lastEventPtr = evPtr;
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} else if (position == TCL_QUEUE_HEAD) {
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/*
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* Push the event on the head of the queue.
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*/
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evPtr->nextPtr = firstEventPtr;
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if (firstEventPtr == NULL) {
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|
lastEventPtr = evPtr;
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|
}
|
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|
firstEventPtr = evPtr;
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|
} else if (position == TCL_QUEUE_MARK) {
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/*
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* Insert the event after the current marker event and advance
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* the marker to the new event.
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*/
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if (markerEventPtr == NULL) {
|
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evPtr->nextPtr = firstEventPtr;
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firstEventPtr = evPtr;
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} else {
|
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evPtr->nextPtr = markerEventPtr->nextPtr;
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markerEventPtr->nextPtr = evPtr;
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|
}
|
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|
markerEventPtr = evPtr;
|
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if (evPtr->nextPtr == NULL) {
|
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|
lastEventPtr = evPtr;
|
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|
}
|
|||
|
}
|
|||
|
}
|
|||
|
|
|||
|
/*
|
|||
|
*----------------------------------------------------------------------
|
|||
|
*
|
|||
|
* 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;
|
|||
|
|
|||
|
for (prevPtr = (Tcl_Event *) NULL, evPtr = firstEventPtr;
|
|||
|
evPtr != (Tcl_Event *) NULL;
|
|||
|
) {
|
|||
|
if ((*proc) (evPtr, clientData) == 1) {
|
|||
|
if (firstEventPtr == evPtr) {
|
|||
|
firstEventPtr = evPtr->nextPtr;
|
|||
|
if (evPtr->nextPtr == (Tcl_Event *) NULL) {
|
|||
|
lastEventPtr = (Tcl_Event *) NULL;
|
|||
|
}
|
|||
|
} else {
|
|||
|
prevPtr->nextPtr = evPtr->nextPtr;
|
|||
|
}
|
|||
|
hold = evPtr;
|
|||
|
evPtr = evPtr->nextPtr;
|
|||
|
ckfree((char *) hold);
|
|||
|
} else {
|
|||
|
prevPtr = evPtr;
|
|||
|
evPtr = evPtr->nextPtr;
|
|||
|
}
|
|||
|
}
|
|||
|
}
|
|||
|
|
|||
|
/*
|
|||
|
*----------------------------------------------------------------------
|
|||
|
*
|
|||
|
* ServiceEvent --
|
|||
|
*
|
|||
|
* Process one event from the event queue. This routine is called
|
|||
|
* by the notifier whenever it wants Tk to process an event.
|
|||
|
*
|
|||
|
* 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.
|
|||
|
*
|
|||
|
*----------------------------------------------------------------------
|
|||
|
*/
|
|||
|
|
|||
|
static int
|
|||
|
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;
|
|||
|
|
|||
|
/*
|
|||
|
* 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 = 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 (firstEventPtr == evPtr) {
|
|||
|
firstEventPtr = evPtr->nextPtr;
|
|||
|
if (evPtr->nextPtr == NULL) {
|
|||
|
lastEventPtr = NULL;
|
|||
|
}
|
|||
|
} else {
|
|||
|
for (prevPtr = firstEventPtr; prevPtr->nextPtr != evPtr;
|
|||
|
prevPtr = prevPtr->nextPtr) {
|
|||
|
/* Empty loop body. */
|
|||
|
}
|
|||
|
prevPtr->nextPtr = evPtr->nextPtr;
|
|||
|
if (evPtr->nextPtr == NULL) {
|
|||
|
lastEventPtr = prevPtr;
|
|||
|
}
|
|||
|
}
|
|||
|
if (markerEventPtr == evPtr) {
|
|||
|
markerEventPtr = NULL;
|
|||
|
}
|
|||
|
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_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 (!blockTimeSet || (timePtr->sec < blockTime.sec)
|
|||
|
|| ((timePtr->sec == blockTime.sec)
|
|||
|
&& (timePtr->usec < blockTime.usec))) {
|
|||
|
blockTime = *timePtr;
|
|||
|
blockTimeSet = 1;
|
|||
|
}
|
|||
|
}
|
|||
|
|
|||
|
/*
|
|||
|
*----------------------------------------------------------------------
|
|||
|
*
|
|||
|
* 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. */
|
|||
|
{
|
|||
|
TclEventSource *sourcePtr;
|
|||
|
Tcl_Time *timePtr;
|
|||
|
|
|||
|
/*
|
|||
|
* No event flags is equivalent to TCL_ALL_EVENTS.
|
|||
|
*/
|
|||
|
|
|||
|
if ((flags & TCL_ALL_EVENTS) == 0) {
|
|||
|
flags |= TCL_ALL_EVENTS;
|
|||
|
}
|
|||
|
|
|||
|
/*
|
|||
|
* The core of this procedure is an infinite loop, even though
|
|||
|
* we only service one event. The reason for this is that we
|
|||
|
* might think we have an event ready (e.g. the connection to
|
|||
|
* the server becomes readable), but then we might discover that
|
|||
|
* there's nothing interesting on that connection, so no event
|
|||
|
* was serviced. Or, the select operation could return prematurely
|
|||
|
* due to a signal. The easiest thing in both these cases is
|
|||
|
* just to loop back and try again.
|
|||
|
*/
|
|||
|
|
|||
|
while (1) {
|
|||
|
|
|||
|
/*
|
|||
|
* The first thing we do is to service any asynchronous event
|
|||
|
* handlers.
|
|||
|
*/
|
|||
|
|
|||
|
if (Tcl_AsyncReady()) {
|
|||
|
(void) Tcl_AsyncInvoke((Tcl_Interp *) NULL, 0);
|
|||
|
return 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_IDLE_EVENTS) {
|
|||
|
flags = TCL_IDLE_EVENTS|TCL_DONT_WAIT;
|
|||
|
goto idleEvents;
|
|||
|
}
|
|||
|
|
|||
|
/*
|
|||
|
* Ask Tk to service a queued event, if there are any.
|
|||
|
*/
|
|||
|
|
|||
|
if (ServiceEvent(flags)) {
|
|||
|
return 1;
|
|||
|
}
|
|||
|
|
|||
|
/*
|
|||
|
* There are no events already queued. Invoke all of the
|
|||
|
* event sources to give them a chance to setup for the wait.
|
|||
|
*/
|
|||
|
|
|||
|
blockTimeSet = 0;
|
|||
|
for (sourcePtr = tclFirstEventSourcePtr; sourcePtr != NULL;
|
|||
|
sourcePtr = sourcePtr->nextPtr) {
|
|||
|
(*sourcePtr->setupProc)(sourcePtr->clientData, flags);
|
|||
|
}
|
|||
|
if ((flags & TCL_DONT_WAIT) ||
|
|||
|
((flags & TCL_IDLE_EVENTS) && TclIdlePending())) {
|
|||
|
/*
|
|||
|
* Don't block: there are idle events waiting, or we don't
|
|||
|
* care about idle events anyway, or the caller asked us not
|
|||
|
* to block.
|
|||
|
*/
|
|||
|
|
|||
|
blockTime.sec = 0;
|
|||
|
blockTime.usec = 0;
|
|||
|
timePtr = &blockTime;
|
|||
|
} else if (blockTimeSet) {
|
|||
|
timePtr = &blockTime;
|
|||
|
} else {
|
|||
|
timePtr = NULL;
|
|||
|
}
|
|||
|
|
|||
|
/*
|
|||
|
* Wait until an event occurs or the timer expires.
|
|||
|
*/
|
|||
|
|
|||
|
if (Tcl_WaitForEvent(timePtr) == TCL_ERROR) {
|
|||
|
return 0;
|
|||
|
}
|
|||
|
|
|||
|
/*
|
|||
|
* Give each of the event sources a chance to queue events,
|
|||
|
* then call ServiceEvent and give it another chance to
|
|||
|
* service events.
|
|||
|
*/
|
|||
|
|
|||
|
for (sourcePtr = tclFirstEventSourcePtr; sourcePtr != NULL;
|
|||
|
sourcePtr = sourcePtr->nextPtr) {
|
|||
|
(*sourcePtr->checkProc)(sourcePtr->clientData, flags);
|
|||
|
}
|
|||
|
if (ServiceEvent(flags)) {
|
|||
|
return 1;
|
|||
|
}
|
|||
|
|
|||
|
/*
|
|||
|
* We've tried everything at this point, but nobody 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) && TclServiceIdle()) {
|
|||
|
return 1;
|
|||
|
}
|
|||
|
if (flags & TCL_DONT_WAIT) {
|
|||
|
return 0;
|
|||
|
}
|
|||
|
}
|
|||
|
}
|