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Clementine-audio-player-Mac.../ext/libclementine-common/core/closure.cpp
Jim Broadus dbe67bf32b Fix closure timing hole.
When a closure involves an ObjectHelper, a connection is made from the
receiver's destroyed signal and the helper object's deleteLater slot. Since
the signal between the sender and the helper object isn't disconnected until
either object is actually destroyed, this leaves a hole where the helper
holds a pointer to an invalid receiver object, but is still able to receive
the signal connected to its Invoke slot.

Instead of connecting the destroyed signal to deleteLater, connect it to a new
TearDown slot that immediately disconnects the signal then calls deleteLater.
2020-01-11 00:53:35 -08:00

73 lines
2.2 KiB
C++

/* This file is part of Clementine.
Copyright 2011, David Sansome <me@davidsansome.com>
Clementine is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Clementine is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Clementine. If not, see <http://www.gnu.org/licenses/>.
*/
#include "closure.h"
#include "core/timeconstants.h"
namespace _detail {
ClosureBase::ClosureBase(ObjectHelper* helper) : helper_(helper) {}
ClosureBase::~ClosureBase() {}
CallbackClosure::CallbackClosure(QObject* sender, const char* signal,
std::function<void()> callback)
: ClosureBase(new ObjectHelper(sender, signal, this)),
callback_(callback) {}
void CallbackClosure::Invoke() { callback_(); }
ObjectHelper* ClosureBase::helper() const { return helper_; }
ObjectHelper::ObjectHelper(QObject* sender, const char* signal,
ClosureBase* closure)
: closure_(closure) {
connection_ = connect(sender, signal, SLOT(Invoked()));
connect(sender, SIGNAL(destroyed()), SLOT(TearDown()));
}
void ObjectHelper::TearDown() {
// For the case that the receiver has been destroyed, disconnect the signal
// so that Invoke isn't called.
disconnect(connection_);
deleteLater();
}
void ObjectHelper::Invoked() {
closure_->Invoke();
deleteLater();
}
void Unpack(QList<QGenericArgument>*) {}
} // namespace _detail
_detail::ClosureBase* NewClosure(QObject* sender, const char* signal,
std::function<void()> callback) {
return new _detail::CallbackClosure(sender, signal, callback);
}
void DoAfter(QObject* receiver, const char* slot, int msec) {
QTimer::singleShot(msec, receiver, slot);
}
void DoInAMinuteOrSo(QObject* receiver, const char* slot) {
int msec = (60 + (qrand() % 60)) * kMsecPerSec;
DoAfter(receiver, slot, msec);
}