Re: [PATCH v2] ole32: Return IUnknown from GITCF_CreateInstance if requested

[Huw Davies]

On Sat, Jul 07, 2018 at 02:30:25PM +0200, Alex Henrie wrote:
> Signed-off-by: Alex Henrie
>
> Without this patch, ArcMap.exe (part of ArcGIS Desktop 10.6) crashes
> shortly after starting.
>
> v2: Move the error message to the QueryInterface function and clean up
> that function a bit.
>
> dlls/ole32/git.c | 22 ++++++++--------------
>  1 file changed, 8 insertions(+), 14 deletions(-)
>
> diff --git a/dlls/ole32/git.c b/dlls/ole32/git.c
> index f7a0460154..e2ed8be91d 100644
> --- a/dlls/ole32/git.c
> +++ b/dlls/ole32/git.c
> @@ -117,18 +117,18 @@ StdGlobalInterfaceTable_QueryInterface(IGlobalInterfaceTable* iface,
>    /* Make sure silly coders can't crash us */
>    if (ppvObject == 0) return E_INVALIDARG;
> - *ppvObject = 0; /* assume we don't have the interface */
> - /* Do we implement that interface? */
>  if (IsEqualIID(&IID_IUnknown, riid) ||
>      IsEqualIID(&IID_IGlobalInterfaceTable, riid))
> - {
> - IGlobalInterfaceTable_AddRef(iface);
> *ppvObject = iface;
> - else
> - return E_NOINTERFACE;
> - return S_OK;
> - }
> - /* Now inc the refcount */
> - IGlobalInterfaceTable_AddRef(iface);
> - return S_OK;
> - *ppvObject = NULL;
> - ERR("(%s), not supported.\n", debugstr_guid(riid));
> - return E_NOINTERFACE;
>
> }

I don't think there's any need to re-write this, it looks ok as it is.
You can add a FIXME (not an ERR) to the else block if you want.
> static ULONG WINAPI
> @@ -314,13 +314,7 @@ static HRESULT WINAPI
>  GITCF_CreateInstance(LPCLASSFACTORY iface, LPUNKNOWN pUnk,
>                       REFIID riid, LPVOID *ppv)
>  {
> - if (IsEqualIID(riid,&IID_IGlobalInterfaceTable)) {
> - IGlobalInterfaceTable *git = get_std_git();
> - return IGlobalInterfaceTable_QueryInterface(git, riid, ppv);
> - }
> -
> - FIXME("(%s), not supported.\n",debugstr_guid(riid));
> - return E_NOINTERFACE;
> - return IGlobalInterfaceTable_QueryInterface(get_std_git(), riid, ppv);
>
> }

What you should do is here is to something like:

IGlobalInterfaceTable *git = get_std_git();
  hr = IGlobalInterfaceTable_QI(git, riid, ppv);
  IGlobalInterfaceTable_Release(git);
  return hr;

It doesn't really matter in this case because the git is a static
object, but it's good practice to keep the ref counts in order.

Huw.