[PATCH] joy.cpl: Check if effect is allocated before releasing it

[Tim Schumacher]

Hello Alistair,

I don't know for sure why creating the effect failed (and I
can't check either, because the issues are seemingly gone after
a reboot), but I can only assume that it is/was something in
SetParameters, since the only occasion where something can fail
without printing a log message is there.

Tim

On 19.05.19 13:21, Alistair Leslie-Hughes wrote:
> Hi Tim,
>
> Thanks.  After looking at it again,  your solution is OK.
>
> Do you know why an effect is failing to create?
>
> Regards
>
> Alistair.
>
>
> On 19/5/19 8:55 pm, Tim Schumacher wrote:
>> Hello Alistair,
>>
>> I thought about fixing the problem that way (since it would be
>> the cleaner solution), but the length of the effects array is
>> determined by the num_effects value (which the destroy loop
>> depends on as well), and that value isn't affected by effects
>> failing to be created.
>>
>> Therefore, we are going to end up with some empty fields, no matter
>> what we do, so I thought this would be the best solution (unless
>> decrementing num_effects when a failure occurs and moving the null
>> fields to the end of the array (hoping that nothing ever accesses
>> them) is an acceptable solution).
>>
>> Tim
>>
>> On 19.05.19 10:49, Alistair Leslie-Hughes wrote:
>>> Hi Tim,
>>>
>>> It would be better to stop the adding of NULL effects.
>>>
>>> function ff_effects_callback
>>>
>>> hr = IDirectInputDevice2_CreateEffect(
>>>           joystick->device, &pdei->guid, &dieffect,
>>> &joystick->effects[joystick->cur_effect].effect, NULL);
>>>
>>> /* hr is assigned but never checked. */
>>>
>>>
>>> Best Regards
>>>
>>> Alistair.
>>>
>>> On 19/5/19 5:02 am, Tim Schumacher wrote:
>>>> Since IDirectInputEffect_Release(obj) is just a macro for (obj)->Release(),
>>>> the program crashes if the effect we are trying to release is null.
>>>> This mostly happens when the effect failed to allocate in the first place.
>>>>
>>>> Signed-off-by: Tim Schumacher <timschumi at gmx.de>
>>>> ---
>>>>    dlls/joy.cpl/main.c | 3 ++-
>>>>    1 file changed, 2 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/dlls/joy.cpl/main.c b/dlls/joy.cpl/main.c
>>>> index 9768917641..06084f3166 100644
>>>> --- a/dlls/joy.cpl/main.c
>>>> +++ b/dlls/joy.cpl/main.c
>>>> @@ -137,7 +137,8 @@ static void destroy_joysticks(struct JoystickData *data)
>>>>            if (data->joysticks[i].forcefeedback && data->joysticks[i].num_effects > 0)
>>>>            {
>>>>                for (j = 0; j < data->joysticks[i].num_effects; j++)
>>>> -                IDirectInputEffect_Release(data->joysticks[i].effects[j].effect);
>>>> +                if (data->joysticks[i].effects[j].effect)
>>>> +                    IDirectInputEffect_Release(data->joysticks[i].effects[j].effect);
>>>>
>>>>                HeapFree(GetProcessHeap(), 0, data->joysticks[i].effects);
>>>>            }
>>>> --
>>>> 2.21.0
>>>>
>>>>
>>>>