308 lines
9.4 KiB
C
308 lines
9.4 KiB
C
/*
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* tkError.c --
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*
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* This file provides a high-performance mechanism for
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* selectively dealing with errors that occur in talking
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* to the X server. This is useful, for example, when
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* communicating with a window that may not exist.
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*
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* Copyright (c) 1990-1994 The Regents of the University of California.
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* Copyright (c) 1994-1995 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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* SCCS: @(#) tkError.c 1.23 97/04/25 16:51:27
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*/
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#include "tkPort.h"
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#include "tkInt.h"
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/*
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* The default X error handler gets saved here, so that it can
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* be invoked if an error occurs that we can't handle.
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*/
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static int (*defaultHandler) _ANSI_ARGS_((Display *display,
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XErrorEvent *eventPtr)) = NULL;
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/*
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* Forward references to procedures declared later in this file:
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*/
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static int ErrorProc _ANSI_ARGS_((Display *display,
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XErrorEvent *errEventPtr));
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/*
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*--------------------------------------------------------------
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*
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* Tk_CreateErrorHandler --
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*
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* Arrange for all a given procedure to be invoked whenever
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* certain errors occur.
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*
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* Results:
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* The return value is a token identifying the handler;
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* it must be passed to Tk_DeleteErrorHandler to delete the
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* handler.
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*
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* Side effects:
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* If an X error occurs that matches the error, request,
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* and minor arguments, then errorProc will be invoked.
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* ErrorProc should have the following structure:
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*
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* int
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* errorProc(clientData, errorEventPtr)
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* caddr_t clientData;
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* XErrorEvent *errorEventPtr;
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* {
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* }
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*
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* The clientData argument will be the same as the clientData
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* argument to this procedure, and errorEvent will describe
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* the error. If errorProc returns 0, it means that it
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* completely "handled" the error: no further processing
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* should be done. If errorProc returns 1, it means that it
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* didn't know how to deal with the error, so we should look
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* for other error handlers, or invoke the default error
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* handler if no other handler returns zero. Handlers are
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* invoked in order of age: youngest handler first.
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*
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* Note: errorProc will only be called for errors associated
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* with X requests made AFTER this call, but BEFORE the handler
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* is deleted by calling Tk_DeleteErrorHandler.
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*
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*--------------------------------------------------------------
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*/
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Tk_ErrorHandler
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Tk_CreateErrorHandler(display, error, request, minorCode, errorProc, clientData)
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Display *display; /* Display for which to handle
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* errors. */
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int error; /* Consider only errors with this
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* error_code (-1 means consider
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* all errors). */
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int request; /* Consider only errors with this
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* major request code (-1 means
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* consider all major codes). */
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int minorCode; /* Consider only errors with this
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* minor request code (-1 means
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* consider all minor codes). */
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Tk_ErrorProc *errorProc; /* Procedure to invoke when a
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* matching error occurs. NULL means
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* just ignore matching errors. */
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ClientData clientData; /* Arbitrary value to pass to
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* errorProc. */
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{
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register TkErrorHandler *errorPtr;
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register TkDisplay *dispPtr;
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/*
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* Find the display. If Tk doesn't know about this display then
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* it's an error: panic.
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*/
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dispPtr = TkGetDisplay(display);
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if (dispPtr == NULL) {
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panic("Unknown display passed to Tk_CreateErrorHandler");
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}
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/*
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* Make sure that X calls us whenever errors occur.
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*/
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if (defaultHandler == NULL) {
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defaultHandler = XSetErrorHandler(ErrorProc);
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}
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/*
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* Create the handler record.
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*/
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errorPtr = (TkErrorHandler *) ckalloc(sizeof(TkErrorHandler));
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errorPtr->dispPtr = dispPtr;
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errorPtr->firstRequest = NextRequest(display);
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errorPtr->lastRequest = (unsigned) -1;
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errorPtr->error = error;
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errorPtr->request = request;
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errorPtr->minorCode = minorCode;
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errorPtr->errorProc = errorProc;
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errorPtr->clientData = clientData;
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errorPtr->nextPtr = dispPtr->errorPtr;
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dispPtr->errorPtr = errorPtr;
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return (Tk_ErrorHandler) errorPtr;
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}
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/*
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*--------------------------------------------------------------
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*
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* Tk_DeleteErrorHandler --
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*
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* Do not use an error handler anymore.
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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 handler denoted by the "handler" argument will not
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* be invoked for any X errors associated with requests
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* made after this call. However, if errors arrive later
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* for requests made BEFORE this call, then the handler
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* will still be invoked. Call XSync if you want to be
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* sure that all outstanding errors have been received
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* and processed.
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*
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*--------------------------------------------------------------
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*/
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void
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Tk_DeleteErrorHandler(handler)
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Tk_ErrorHandler handler; /* Token for handler to delete;
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* was previous return value from
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* Tk_CreateErrorHandler. */
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{
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register TkErrorHandler *errorPtr = (TkErrorHandler *) handler;
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register TkDisplay *dispPtr = errorPtr->dispPtr;
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errorPtr->lastRequest = NextRequest(dispPtr->display) - 1;
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/*
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* Every once-in-a-while, cleanup handlers that are no longer
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* active. We probably won't be able to free the handler that
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* was just deleted (need to wait for any outstanding requests to
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* be processed by server), but there may be previously-deleted
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* handlers that are now ready for garbage collection. To reduce
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* the cost of the cleanup, let a few dead handlers pile up, then
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* clean them all at once. This adds a bit of overhead to errors
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* that might occur while the dead handlers are hanging around,
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* but reduces the overhead of scanning the list to clean up
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* (particularly if there are many handlers that stay around
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* forever).
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*/
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dispPtr->deleteCount += 1;
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if (dispPtr->deleteCount >= 10) {
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register TkErrorHandler *prevPtr;
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TkErrorHandler *nextPtr;
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int lastSerial;
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dispPtr->deleteCount = 0;
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lastSerial = LastKnownRequestProcessed(dispPtr->display);
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errorPtr = dispPtr->errorPtr;
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for (prevPtr = NULL; errorPtr != NULL; errorPtr = nextPtr) {
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nextPtr = errorPtr->nextPtr;
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if ((errorPtr->lastRequest != (unsigned long) -1)
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&& (errorPtr->lastRequest <= (unsigned long) lastSerial)) {
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if (prevPtr == NULL) {
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dispPtr->errorPtr = nextPtr;
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} else {
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prevPtr->nextPtr = nextPtr;
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}
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ckfree((char *) errorPtr);
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continue;
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}
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prevPtr = errorPtr;
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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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* ErrorProc --
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*
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* This procedure is invoked by the X system when error
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* events arrive.
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*
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* Results:
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* If it returns, the return value is zero. However,
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* it is possible that one of the error handlers may
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* just exit.
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*
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* Side effects:
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* This procedure does two things. First, it uses the
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* serial # in the error event to eliminate handlers whose
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* expiration serials are now in the past. Second, it
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* invokes any handlers that want to deal with the error.
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*
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*--------------------------------------------------------------
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*/
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static int
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ErrorProc(display, errEventPtr)
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Display *display; /* Display for which error
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* occurred. */
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register XErrorEvent *errEventPtr; /* Information about error. */
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{
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register TkDisplay *dispPtr;
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register TkErrorHandler *errorPtr;
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/*
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* See if we know anything about the display. If not, then
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* invoke the default error handler.
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*/
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dispPtr = TkGetDisplay(display);
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if (dispPtr == NULL) {
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goto couldntHandle;
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}
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/*
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* Otherwise invoke any relevant handlers for the error, in order.
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*/
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for (errorPtr = dispPtr->errorPtr; errorPtr != NULL;
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errorPtr = errorPtr->nextPtr) {
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if ((errorPtr->firstRequest > errEventPtr->serial)
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|| ((errorPtr->error != -1)
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&& (errorPtr->error != errEventPtr->error_code))
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|| ((errorPtr->request != -1)
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&& (errorPtr->request != errEventPtr->request_code))
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|| ((errorPtr->minorCode != -1)
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&& (errorPtr->minorCode != errEventPtr->minor_code))
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|| ((errorPtr->lastRequest != (unsigned long) -1)
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&& (errorPtr->lastRequest < errEventPtr->serial))) {
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continue;
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}
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if (errorPtr->errorProc == NULL) {
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return 0;
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} else {
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if ((*errorPtr->errorProc)(errorPtr->clientData,
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errEventPtr) == 0) {
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return 0;
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}
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}
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}
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/*
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* See if the error is a BadWindow error. If so, and it refers
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* to a window that still exists in our window table, then ignore
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* the error. Errors like this can occur if a window owned by us
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* is deleted by someone externally, like a window manager. We'll
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* ignore the errors at least long enough to clean up internally and
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* remove the entry from the window table.
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*
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* NOTE: For embedding, we must also check whether the window was
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* recently deleted. If so, it may be that Tk generated operations on
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* windows that were deleted by the container. Now we are getting
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* the errors (BadWindow) after Tk already deleted the window itself.
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*/
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if ((errEventPtr->error_code == BadWindow) &&
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((Tk_IdToWindow(display, (Window) errEventPtr->resourceid) !=
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NULL) ||
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(TkpWindowWasRecentlyDeleted((Window) errEventPtr->resourceid,
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dispPtr)))) {
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return 0;
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}
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/*
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* We couldn't handle the error. Use the default handler.
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*/
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couldntHandle:
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return (*defaultHandler)(display, errEventPtr);
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}
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