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

[Alistair Leslie-Hughes]

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
>>>
>>>
>>>