diff options
author | Alex Trotsenko <alex1973tr@gmail.com> | 2018-03-22 17:34:16 +0200 |
---|---|---|
committer | Alex Trotsenko <alex1973tr@gmail.com> | 2018-03-27 15:08:46 +0000 |
commit | cdbd68fc2fab60fdf6834615db586715b01f4380 (patch) | |
tree | 5af85c1a29d8b83c0bf0e001a6fbb1bb340a8dcc /src/corelib/kernel/qwineventnotifier.cpp | |
parent | 09f3b19f989d83e01bd53f512b928550ee81ec2c (diff) |
Allow QWinEventNotifier to coexist with waiting functions
Many subclasses of QIODevice have a functionality to block execution
until some asynchronous I/O operation completes. In case we are using
QWinEventNotifier, a typical reimplemented waitFor{ReadyRead
|BytesWritten}() function could look like:
if (WaitForSingleObject(notifier.handle(),...) == WAIT_OBJECT_0) {
notifier.setEnabled(false);
ResetEvent(notifier.handle());
bool res = GetOverlappedResult(...);
...
return true;
}
Despite the fact that the operation ends synchronously, it leaves the
notifier in a state that indicates it has received the event, so its
next call to setEnabled(true) will produce a fake notification.
So, we should reset a notifier's history before enabling it again.
Change-Id: I62a9dd809ce6a7a40e9d8038f2a49299b36f8142
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>
Diffstat (limited to 'src/corelib/kernel/qwineventnotifier.cpp')
-rw-r--r-- | src/corelib/kernel/qwineventnotifier.cpp | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/src/corelib/kernel/qwineventnotifier.cpp b/src/corelib/kernel/qwineventnotifier.cpp index 24de491326..85d4ad4fa9 100644 --- a/src/corelib/kernel/qwineventnotifier.cpp +++ b/src/corelib/kernel/qwineventnotifier.cpp @@ -157,7 +157,6 @@ void QWinEventNotifier::setHandle(HANDLE hEvent) Q_D(QWinEventNotifier); setEnabled(false); d->handleToEvent = hEvent; - d->signaledCount = 0; } /*! @@ -209,10 +208,12 @@ void QWinEventNotifier::setEnabled(bool enable) return; } - if (enable) + if (enable) { + d->signaledCount = 0; eventDispatcher->registerEventNotifier(this); - else + } else { eventDispatcher->unregisterEventNotifier(this); + } } /*! |