NekoCWD/libcamera
NekoCWD/libcamera
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages 7 Wiki Activity Actions

libcamera: signal: Disconnect signal automatically on slot deletion

Browse source 
When a signal is connected to a member function slot, the slot is not
disconnected when the slot object is deleted. This can lead to calling a
member function of a deleted object if the signal isn't disconnected
manually by the slot object's destructor.

Make signal handling easier by implementing a base Object class that
tracks all connected signals and disconnects from them automatically
when the object is deleted, using template specialization resolution in
the Signal class.

As inheriting from the Object class may to a too harsh requirement for
Signal usage in applications, keep the existing behaviour working if the
slot doesn't inherit from the Object class. We may reconsider this later
and require all slot objects to inherit from the Object class.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
This commit is contained in:
Laurent Pinchart 2019-02-08 00:24:14 +02:00
parent 73a1bea709
commit 98bd9cb8c9
8 changed files with 210 additions and 36 deletions
Download patch file Download diff file Expand all files Collapse all files

37
test/signal.cpp
View file

@ -8,6 +8,7 @@
#include <iostream>
#include <string.h>
#include <libcamera/object.h>
#include <libcamera/signal.h>
#include "test.h"
@ -22,6 +23,15 @@ static void slotStatic(int value)
valueStatic_ = value;
}
class SlotObject : public Object
{
public:
void slot()
{
valueStatic_ = 1;
}
};
class SignalTest : public Test
{
protected:
@ -139,6 +149,33 @@ protected:
return TestFail;
}
/*
* Test automatic disconnection on object deletion. Connect the
* slot twice to ensure all instances are disconnected.
*/
signalVoid_.disconnect();
SlotObject *slotObject = new SlotObject();
signalVoid_.connect(slotObject, &SlotObject::slot);
signalVoid_.connect(slotObject, &SlotObject::slot);
delete slotObject;
valueStatic_ = 0;
signalVoid_.emit();
if (valueStatic_ != 0) {
cout << "Signal disconnection on object deletion test failed" << endl;
return TestFail;
}
/*
* Test that signal deletion disconnects objects. This shall
* not generate any valgrind warning.
*/
Signal<> *signal = new Signal<>();
slotObject = new SlotObject();
signal->connect(slotObject, &SlotObject::slot);
delete signal;
delete slotObject;
return TestPass;
}