windowscodecs: Add support for IMILBitmapSource interface.

[Charles Davis]

On May 19, 2013, at 9:14 PM, Dmitry Timoshkov wrote:
> diff --git a/dlls/windowscodecs/bitmap.c b/dlls/windowscodecs/bitmap.c
> index f8904df..646f3a7 100644
> --- a/dlls/windowscodecs/bitmap.c
> +++ b/dlls/windowscodecs/bitmap.c
> @@ -446,6 +471,226 @@ static const IWICBitmapVtbl BitmapImpl_Vtbl = {
>     BitmapImpl_SetResolution
> };
> 
> +static HRESULT WINAPI IMILBitmapImpl_QueryInterface(IMILBitmapSource *iface, REFIID iid,
> +    void **ppv)
> +{
> +    BitmapImpl *This = impl_from_IMILBitmapSource(iface);
> +    TRACE("(%p,%s,%p)\n", iface, debugstr_guid(iid), ppv);
> +
> +    if (!ppv) return E_INVALIDARG;
> +
> +    if (IsEqualIID(&IID_IUnknown, iid) ||
> +        IsEqualIID(&IID_IMILBitmapSource, iid))
> +    {
> +        *ppv = &This->IMILBitmapSource_iface;
> +        IUnknown_AddRef((IUnknown*)*ppv);
> +        return S_OK;
> +    }
You're violating COM rules here: when you QI an object for an interface pointer, the QI must always return the same result no matter what. Here, however, you're returning this interface pointer in response to a query for IUnknown, when the already-existing QueryInterface method on the IWICBitmap interface returns *itself* for IUnknown! Now when you QI for IUnknown on both of these interfaces, they won't compare equal. (I suspect you're not convinced. After all, native might violate COM rules here, too. I doubt that (see below), but it might. So, write a test that QI's for IUnknown from both interfaces, and checks if they're equal or not. Then we'll see who's right.)
> diff --git a/dlls/windowscodecs/wincodecs_private.h b/dlls/windowscodecs/wincodecs_private.h
> index dddb327..29f7726 100644
> --- a/dlls/windowscodecs/wincodecs_private.h
> +++ b/dlls/windowscodecs/wincodecs_private.h
> @@ -27,6 +27,46 @@ DEFINE_GUID(GUID_WineContainerFormatTga, 0x0c44fda1,0xa5c5,0x4298,0x96,0x85,0x47
> 
> DEFINE_GUID(GUID_VendorWine, 0xddf46da1,0x7dc1,0x404e,0x98,0xf2,0xef,0xa4,0x8d,0xfc,0x95,0x0a);
> 
> +DEFINE_GUID(IID_IMILBitmapSource,0x7543696a,0xbc8d,0x46b0,0x5f,0x81,0x8d,0x95,0x72,0x89,0x72,0xbe);
> +#define INTERFACE IMILBitmapSource
> +DECLARE_INTERFACE_(IMILBitmapSource,IUnknown)
> +{
> +    /*** IUnknown methods ***/
> +    STDMETHOD_(HRESULT,QueryInterface)(THIS_ REFIID,void **) PURE;
You know you can just use the STDMETHOD() macro (no trailing underscore), e.g.:

       STDMETHOD(QueryInterface)(THIS_ REFIID,void **) PURE;

for methods that return an HRESULT, right? Or do you prefer explicitly declaring the return type like that, even if it is more typing?
> +    STDMETHOD_(ULONG,AddRef)(THIS) PURE;
> +    STDMETHOD_(ULONG,Release)(THIS) PURE;
> +    /*** IMILBitmapSource methods ***/
> +    STDMETHOD_(HRESULT,GetSize)(THIS_ UINT *,UINT *);
> +    STDMETHOD_(HRESULT,GetPixelFormat)(THIS_ int *);
> +    STDMETHOD_(HRESULT,GetResolution)(THIS_ double *,double *);
> +    STDMETHOD_(HRESULT,CopyPalette)(THIS_ IWICPalette *);
> +    STDMETHOD_(HRESULT,CopyPixels)(THIS_ const WICRect *,UINT,UINT,BYTE *);
> +    STDMETHOD_(HRESULT,UnknownMethod1)(THIS_ void **);
> +};
> +#undef INTERFACE
> +
> +#define INTERFACE IMILUnknown1
> +DECLARE_INTERFACE_(IMILUnknown1,IUnknown)
> +{
> +    /*** IUnknown methods ***/
> +    STDMETHOD_(HRESULT,QueryInterface)(THIS_ REFIID,void **) PURE;
> +    STDMETHOD_(ULONG,AddRef)(THIS) PURE;
> +    STDMETHOD_(ULONG,Release)(THIS) PURE;
> +};
> +#undef INTERFACE
Wouldn't that just make this interface a plain old IUnknown? Or does it have its own IID? (Or does that not even matter, given that it's returned from that "UnknownMethod1" above?) If it is nothing more than a plain IUnknown, why did you even add this, since it doesn't really extend the IUnknown interface with any new methods?

It's telling that its v-table is the very first v-table in the object. This probably indicates that this really is the canonical IUnknown (i.e. the one that gets returned when you QI for IUnknown), and the other interfaces' IUnknown methods just delegate to this one. If I haven't missed my guess about this object's QI implementation, then this is the IUnknown that should get returned from a QI for IUnknown.

This might actually be an object that supports aggregation; you may want to test for that, too ;).

Chip