From e24a4976bebd7ca90deac2b40c08900625773a99 Mon Sep 17 00:00:00 2001 From: Volker Hilsheimer Date: Wed, 24 Jul 2019 15:05:23 +0200 Subject: QHostInfo: Always post results through the event loop to the receiver MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Lookups performed via QHostInfoRunnable must not synchronously call the user-code's receiver objects, as that would execute user-code in the wrong thread. Instead, post a metacall event through the event loop of the receiver object, or the thread that initiated the lookup. This was done correctly for the trivial cases of empty host name or cached results, so the code generally existed. By moving it from a global function into a member function of QHostInfoResult, we can simply access the required data to construct and post the event. As we process that posted event, we need to check that the context object (which is already guarded via QPointer) is still alive, if we had one in the first place. If we had one, and it's deleted, then abort. [ChangeLog][QtNetwork][QHostInfo] Functors used in the lookupHost overloads are now called correctly in the thread of the context object. When used without context object, the thread that initiates the lookup will run the functor, and is required to run an event loop. Change-Id: I9b38d4f9a23cfc4d9e07bc72de2d2cefe5d0d033 Fixes: QTBUG-76276 Reviewed-by: Edward Welbourne Reviewed-by: Mårten Nordheim --- src/network/kernel/qhostinfo_p.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'src/network/kernel/qhostinfo_p.h') diff --git a/src/network/kernel/qhostinfo_p.h b/src/network/kernel/qhostinfo_p.h index 8898d6ff50..bbf4cc36d1 100644 --- a/src/network/kernel/qhostinfo_p.h +++ b/src/network/kernel/qhostinfo_p.h @@ -84,12 +84,14 @@ class QHostInfoResult : public QObject QPointer receiver = nullptr; QtPrivate::QSlotObjectBase *slotObj = nullptr; + const bool withContextObject = false; public: QHostInfoResult() = default; QHostInfoResult(const QObject *receiver, QtPrivate::QSlotObjectBase *slotObj) : receiver(receiver), - slotObj(slotObj) + slotObj(slotObj), + withContextObject(slotObj && receiver) { connect(QCoreApplication::instance(), &QCoreApplication::aboutToQuit, this, &QObject::deleteLater); @@ -97,10 +99,15 @@ public: moveToThread(receiver->thread()); } + void postResultsReady(const QHostInfo &info); + public Q_SLOTS: inline void emitResultsReady(const QHostInfo &info) { if (slotObj) { + // we used to have a context object, but it's already destroyed + if (withContextObject && !receiver) + return; QHostInfo copy = info; void *args[2] = { 0, reinterpret_cast(©) }; slotObj->call(const_cast(receiver.data()), args); -- cgit v1.2.3