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Diffstat (limited to 'generic/tkError.c')
| -rw-r--r-- | generic/tkError.c | 307 |
1 files changed, 307 insertions, 0 deletions
diff --git a/generic/tkError.c b/generic/tkError.c new file mode 100644 index 0000000..3d52793 --- /dev/null +++ b/generic/tkError.c @@ -0,0 +1,307 @@ +/* + * tkError.c -- + * + * This file provides a high-performance mechanism for + * selectively dealing with errors that occur in talking + * to the X server. This is useful, for example, when + * communicating with a window that may not exist. + * + * Copyright (c) 1990-1994 The Regents of the University of California. + * Copyright (c) 1994-1995 Sun Microsystems, Inc. + * + * See the file "license.terms" for information on usage and redistribution + * of this file, and for a DISCLAIMER OF ALL WARRANTIES. + * + * SCCS: @(#) tkError.c 1.23 97/04/25 16:51:27 + */ + +#include "tkPort.h" +#include "tkInt.h" + +/* + * The default X error handler gets saved here, so that it can + * be invoked if an error occurs that we can't handle. + */ + +static int (*defaultHandler) _ANSI_ARGS_((Display *display, + XErrorEvent *eventPtr)) = NULL; + + +/* + * Forward references to procedures declared later in this file: + */ + +static int ErrorProc _ANSI_ARGS_((Display *display, + XErrorEvent *errEventPtr)); + +/* + *-------------------------------------------------------------- + * + * Tk_CreateErrorHandler -- + * + * Arrange for all a given procedure to be invoked whenever + * certain errors occur. + * + * Results: + * The return value is a token identifying the handler; + * it must be passed to Tk_DeleteErrorHandler to delete the + * handler. + * + * Side effects: + * If an X error occurs that matches the error, request, + * and minor arguments, then errorProc will be invoked. + * ErrorProc should have the following structure: + * + * int + * errorProc(clientData, errorEventPtr) + * caddr_t clientData; + * XErrorEvent *errorEventPtr; + * { + * } + * + * The clientData argument will be the same as the clientData + * argument to this procedure, and errorEvent will describe + * the error. If errorProc returns 0, it means that it + * completely "handled" the error: no further processing + * should be done. If errorProc returns 1, it means that it + * didn't know how to deal with the error, so we should look + * for other error handlers, or invoke the default error + * handler if no other handler returns zero. Handlers are + * invoked in order of age: youngest handler first. + * + * Note: errorProc will only be called for errors associated + * with X requests made AFTER this call, but BEFORE the handler + * is deleted by calling Tk_DeleteErrorHandler. + * + *-------------------------------------------------------------- + */ + +Tk_ErrorHandler +Tk_CreateErrorHandler(display, error, request, minorCode, errorProc, clientData) + Display *display; /* Display for which to handle + * errors. */ + int error; /* Consider only errors with this + * error_code (-1 means consider + * all errors). */ + int request; /* Consider only errors with this + * major request code (-1 means + * consider all major codes). */ + int minorCode; /* Consider only errors with this + * minor request code (-1 means + * consider all minor codes). */ + Tk_ErrorProc *errorProc; /* Procedure to invoke when a + * matching error occurs. NULL means + * just ignore matching errors. */ + ClientData clientData; /* Arbitrary value to pass to + * errorProc. */ +{ + register TkErrorHandler *errorPtr; + register TkDisplay *dispPtr; + + /* + * Find the display. If Tk doesn't know about this display then + * it's an error: panic. + */ + + dispPtr = TkGetDisplay(display); + if (dispPtr == NULL) { + panic("Unknown display passed to Tk_CreateErrorHandler"); + } + + /* + * Make sure that X calls us whenever errors occur. + */ + + if (defaultHandler == NULL) { + defaultHandler = XSetErrorHandler(ErrorProc); + } + + /* + * Create the handler record. + */ + + errorPtr = (TkErrorHandler *) ckalloc(sizeof(TkErrorHandler)); + errorPtr->dispPtr = dispPtr; + errorPtr->firstRequest = NextRequest(display); + errorPtr->lastRequest = (unsigned) -1; + errorPtr->error = error; + errorPtr->request = request; + errorPtr->minorCode = minorCode; + errorPtr->errorProc = errorProc; + errorPtr->clientData = clientData; + errorPtr->nextPtr = dispPtr->errorPtr; + dispPtr->errorPtr = errorPtr; + + return (Tk_ErrorHandler) errorPtr; +} + +/* + *-------------------------------------------------------------- + * + * Tk_DeleteErrorHandler -- + * + * Do not use an error handler anymore. + * + * Results: + * None. + * + * Side effects: + * The handler denoted by the "handler" argument will not + * be invoked for any X errors associated with requests + * made after this call. However, if errors arrive later + * for requests made BEFORE this call, then the handler + * will still be invoked. Call XSync if you want to be + * sure that all outstanding errors have been received + * and processed. + * + *-------------------------------------------------------------- + */ + +void +Tk_DeleteErrorHandler(handler) + Tk_ErrorHandler handler; /* Token for handler to delete; + * was previous return value from + * Tk_CreateErrorHandler. */ +{ + register TkErrorHandler *errorPtr = (TkErrorHandler *) handler; + register TkDisplay *dispPtr = errorPtr->dispPtr; + + errorPtr->lastRequest = NextRequest(dispPtr->display) - 1; + + /* + * Every once-in-a-while, cleanup handlers that are no longer + * active. We probably won't be able to free the handler that + * was just deleted (need to wait for any outstanding requests to + * be processed by server), but there may be previously-deleted + * handlers that are now ready for garbage collection. To reduce + * the cost of the cleanup, let a few dead handlers pile up, then + * clean them all at once. This adds a bit of overhead to errors + * that might occur while the dead handlers are hanging around, + * but reduces the overhead of scanning the list to clean up + * (particularly if there are many handlers that stay around + * forever). + */ + + dispPtr->deleteCount += 1; + if (dispPtr->deleteCount >= 10) { + register TkErrorHandler *prevPtr; + TkErrorHandler *nextPtr; + int lastSerial; + + dispPtr->deleteCount = 0; + lastSerial = LastKnownRequestProcessed(dispPtr->display); + errorPtr = dispPtr->errorPtr; + for (prevPtr = NULL; errorPtr != NULL; errorPtr = nextPtr) { + nextPtr = errorPtr->nextPtr; + if ((errorPtr->lastRequest != (unsigned long) -1) + && (errorPtr->lastRequest <= (unsigned long) lastSerial)) { + if (prevPtr == NULL) { + dispPtr->errorPtr = nextPtr; + } else { + prevPtr->nextPtr = nextPtr; + } + ckfree((char *) errorPtr); + continue; + } + prevPtr = errorPtr; + } + } +} + +/* + *-------------------------------------------------------------- + * + * ErrorProc -- + * + * This procedure is invoked by the X system when error + * events arrive. + * + * Results: + * If it returns, the return value is zero. However, + * it is possible that one of the error handlers may + * just exit. + * + * Side effects: + * This procedure does two things. First, it uses the + * serial # in the error event to eliminate handlers whose + * expiration serials are now in the past. Second, it + * invokes any handlers that want to deal with the error. + * + *-------------------------------------------------------------- + */ + +static int +ErrorProc(display, errEventPtr) + Display *display; /* Display for which error + * occurred. */ + register XErrorEvent *errEventPtr; /* Information about error. */ +{ + register TkDisplay *dispPtr; + register TkErrorHandler *errorPtr; + + /* + * See if we know anything about the display. If not, then + * invoke the default error handler. + */ + + dispPtr = TkGetDisplay(display); + if (dispPtr == NULL) { + goto couldntHandle; + } + + /* + * Otherwise invoke any relevant handlers for the error, in order. + */ + + for (errorPtr = dispPtr->errorPtr; errorPtr != NULL; + errorPtr = errorPtr->nextPtr) { + if ((errorPtr->firstRequest > errEventPtr->serial) + || ((errorPtr->error != -1) + && (errorPtr->error != errEventPtr->error_code)) + || ((errorPtr->request != -1) + && (errorPtr->request != errEventPtr->request_code)) + || ((errorPtr->minorCode != -1) + && (errorPtr->minorCode != errEventPtr->minor_code)) + || ((errorPtr->lastRequest != (unsigned long) -1) + && (errorPtr->lastRequest < errEventPtr->serial))) { + continue; + } + if (errorPtr->errorProc == NULL) { + return 0; + } else { + if ((*errorPtr->errorProc)(errorPtr->clientData, + errEventPtr) == 0) { + return 0; + } + } + } + + /* + * See if the error is a BadWindow error. If so, and it refers + * to a window that still exists in our window table, then ignore + * the error. Errors like this can occur if a window owned by us + * is deleted by someone externally, like a window manager. We'll + * ignore the errors at least long enough to clean up internally and + * remove the entry from the window table. + * + * NOTE: For embedding, we must also check whether the window was + * recently deleted. If so, it may be that Tk generated operations on + * windows that were deleted by the container. Now we are getting + * the errors (BadWindow) after Tk already deleted the window itself. + */ + + if ((errEventPtr->error_code == BadWindow) && + ((Tk_IdToWindow(display, (Window) errEventPtr->resourceid) != + NULL) || + (TkpWindowWasRecentlyDeleted((Window) errEventPtr->resourceid, + dispPtr)))) { + return 0; + } + + /* + * We couldn't handle the error. Use the default handler. + */ + + couldntHandle: + return (*defaultHandler)(display, errEventPtr); +} |