diff options
| -rw-r--r-- | src/corelib/kernel/qabstracteventdispatcher.cpp | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/src/corelib/kernel/qabstracteventdispatcher.cpp b/src/corelib/kernel/qabstracteventdispatcher.cpp index 5619921..002d360 100644 --- a/src/corelib/kernel/qabstracteventdispatcher.cpp +++ b/src/corelib/kernel/qabstracteventdispatcher.cpp @@ -77,10 +77,14 @@ Q_DESTRUCTOR_FUNCTION(timerIdsDestructorFunction) static QBasicAtomicInt nextFreeTimerId = Q_BASIC_ATOMIC_INITIALIZER(1); +static const int TimerIdMask = 0x00ffffff; +static const int TimerSerialMask = ~TimerIdMask & ~0x80000000; +static const int TimerSerialCounter = TimerIdMask + 1; + // avoid the ABA-problem by using 7 of the top 8 bits of the timerId as a serial number static inline int prepareNewValueWithSerialNumber(int oldId, int newId) { - return (newId & 0x00FFFFFF) | ((oldId + 0x01000000) & 0x7f000000); + return (newId & TimerIdMask) | ((oldId + TimerSerialCounter) & TimerSerialMask); } static inline int bucketOffset(int timerId) @@ -136,7 +140,7 @@ int QAbstractEventDispatcherPrivate::allocateTimerId() timerId = nextFreeTimerId; //.loadAcquire(); // ### FIXME Proper memory ordering semantics // which bucket are we looking in? - int which = timerId & 0x00ffffff; + int which = timerId & TimerIdMask; int bucket = bucketOffset(which); int at = bucketIndex(bucket, which); int *b = timerIds[bucket]; @@ -170,7 +174,7 @@ int QAbstractEventDispatcherPrivate::allocateTimerId() // nextFreeTimerId. void QAbstractEventDispatcherPrivate::releaseTimerId(int timerId) { - int which = timerId & 0x00ffffff; + int which = timerId & TimerIdMask; int bucket = bucketOffset(which); int at = bucketIndex(bucket, which); int *b = timerIds[bucket]; @@ -178,7 +182,7 @@ void QAbstractEventDispatcherPrivate::releaseTimerId(int timerId) int freeId, newTimerId; do { freeId = nextFreeTimerId;//.loadAcquire(); // ### FIXME Proper memory ordering semantics - b[at] = freeId & 0x00ffffff; + b[at] = freeId & TimerIdMask; newTimerId = prepareNewValueWithSerialNumber(freeId, timerId); } while (!nextFreeTimerId.testAndSetRelease(freeId, newTimerId)); |