Re: [PATCH v3 2/5] d2d1: Implement d2d_effect_GetInputCount().

[Henri Verbeet]

On Thu, 5 Aug 2021 at 10:06, Ziqing Hui  wrote:
> +static void d2d_effect_cleanup(struct d2d_effect *effect)
> +{
> - heap_free(effect->inputs);
> - ID2D1Factory_Release(effect->factory);
>
> +}

[...]
> -void d2d_effect_init(struct d2d_effect *effect, ID2D1Factory *factory)
> +HRESULT d2d_effect_init(struct d2d_effect *effect, ID2D1Factory *factory)
>  {
>      effect->ID2D1Effect_iface.lpVtbl = &d2d_effect_vtbl;
>      effect->ID2D1Image_iface.lpVtbl = &d2d_effect_image_vtbl;
>      effect->refcount = 1;
> - ID2D1Factory_AddRef(effect->factory = factory);
> -
> - effect->input_count = 1;
> - if (!d2d_array_reserve((void **)&effect->inputs, &effect->inputs_size,
> -
>        effect->input_count, sizeof(*effect->inputs)))
> -
>    goto fail;
> - memset(effect->inputs, 0, sizeof(*effect->inputs) * effect->inputs_size);
> -
> - return S_OK;
> -
>
> +fail:
> - d2d_effect_cleanup(effect);
> - return E_OUTOFMEMORY;
>
> }

If d2d_array_reserve() were to fail, we'd only need to release the
factory reference. (And if we called d2d_array_reserve() before
ID2D1Factory_AddRef(), we could avoid that too.) Calling heap_free()
on a NULL "effect->inputs" works fine of course, but it becomes more
complicated in patch 4/5 of this series. In principle we only ever
want to call _cleanup() functions on fully initialised objects.

Note that we only need to memset() "effect->input_count" inputs here;
that's what we do for SetInputCount() as well in patch 3/5. And in
fact, once we have SetInputCount() in patch 3/5, we can just call it
from d2d_effect_init() to set the initial input count.