diff options
Diffstat (limited to 'generic/tclAsync.c')
| -rw-r--r-- | generic/tclAsync.c | 52 |
1 files changed, 34 insertions, 18 deletions
diff --git a/generic/tclAsync.c b/generic/tclAsync.c index 7d27ffa..8a0691d 100644 --- a/generic/tclAsync.c +++ b/generic/tclAsync.c @@ -11,7 +11,7 @@ * See the file "license.terms" for information on usage and redistribution of * this file, and for a DISCLAIMER OF ALL WARRANTIES. * - * RCS: @(#) $Id: tclAsync.c,v 1.10.6.1 2007/11/12 19:18:13 dgp Exp $ + * RCS: @(#) $Id: tclAsync.c,v 1.10.6.2 2008/06/25 15:56:09 dgp Exp $ */ #include "tclInt.h" @@ -259,6 +259,13 @@ Tcl_AsyncInvoke( * Side effects: * The state associated with the handler is deleted. * + * Failure to locate the handler in current thread private list + * of async handlers will result in panic; exception: the list + * is already empty (potential trouble?). + * Consequently, threads should create and delete handlers + * themselves. I.e. a handler created by one should not be + * deleted by some other thread. + * *---------------------------------------------------------------------- */ @@ -268,31 +275,40 @@ Tcl_AsyncDelete( { ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); AsyncHandler *asyncPtr = (AsyncHandler *) async; - AsyncHandler *prevPtr; + AsyncHandler *prevPtr, *thisPtr; + + /* + * Assure early handling of the constraint + */ + + if (asyncPtr->originThrdId != Tcl_GetCurrentThread()) { + Tcl_Panic("Tcl_AsyncDelete: async handler deleted by the wrong thread"); + } /* - * Conservatively check the existence of the linked list of - * registered handlers, as we may come at this point even - * when the TSD's for the current thread have been already - * garbage-collected. + * If we come to this point when TSD's for the current + * thread have already been garbage-collected, we are + * in the _serious_ trouble. OTOH, we tolerate calling + * with already cleaned-up handler list (should we?). */ Tcl_MutexLock(&tsdPtr->asyncMutex); - if (tsdPtr->firstHandler != NULL ) { - if (tsdPtr->firstHandler == asyncPtr) { + if (tsdPtr->firstHandler != NULL) { + prevPtr = thisPtr = tsdPtr->firstHandler; + while (thisPtr != NULL && thisPtr != asyncPtr) { + prevPtr = thisPtr; + thisPtr = thisPtr->nextPtr; + } + if (thisPtr == NULL) { + Tcl_Panic("Tcl_AsyncDelete: cannot find async handler"); + } + if (asyncPtr == tsdPtr->firstHandler) { tsdPtr->firstHandler = asyncPtr->nextPtr; - if (tsdPtr->firstHandler == NULL) { - tsdPtr->lastHandler = NULL; - } } else { - prevPtr = tsdPtr->firstHandler; - while (prevPtr->nextPtr != asyncPtr) { - prevPtr = prevPtr->nextPtr; - } prevPtr->nextPtr = asyncPtr->nextPtr; - if (tsdPtr->lastHandler == asyncPtr) { - tsdPtr->lastHandler = prevPtr; - } + } + if (asyncPtr == tsdPtr->lastHandler) { + tsdPtr->lastHandler = prevPtr; } } Tcl_MutexUnlock(&tsdPtr->asyncMutex); |