Re: [PATCH v2 2/2] mfplat: Return HRESULT_FROM_WIN32(ERROR_HANDLE_EOF) when reading past the end of a file stream.

[Nikolay Sivov]

On 10/8/21 7:06 AM, Zebediah Figura wrote:
> Signed-off-by: Zebediah Figura
>
> dlls/mfplat/main.c         | 15 ++++++++++++++-
>  dlls/mfplat/tests/mfplat.c |  2 +-
>  2 files changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/dlls/mfplat/main.c b/dlls/mfplat/main.c
> index 7fd713261fc..fb55a8afb21 100644
> --- a/dlls/mfplat/main.c
> +++ b/dlls/mfplat/main.c
> @@ -3843,7 +3843,7 @@ static HRESULT WINAPI bytestream_file_IsEndOfStream(IMFByteStream *iface, BOOL *
>  static HRESULT WINAPI bytestream_file_Read(IMFByteStream *iface, BYTE *buffer, ULONG size, ULONG *read_len)
>  {
>      struct bytestream *stream = impl_from_IMFByteStream(iface);
> - LARGE_INTEGER position;
> - LARGE_INTEGER position, file_size;
> HRESULT hr = S_OK;
> BOOL ret;
>
> @@ -3851,6 +3851,19 @@ static HRESULT WINAPI bytestream_file_Read(IMFByteStream *iface, BYTE *buffer, U
>  EnterCriticalSection(&stream->cs);
>
> - if (!GetFileSizeEx(stream->hfile, &file_size))
> - {
> -
>    LeaveCriticalSection(&stream->cs);
> -
>    return HRESULT_FROM_WIN32(GetLastError());
> - }
> -
> - if (stream->position > file_size.QuadPart)
> - {
> -
>    LeaveCriticalSection(&stream->cs);
> -
>    *read_len = 0;
> -
>    return HRESULT_FROM_WIN32(ERROR_HANDLE_EOF);
> - }
> -

I think this is too explicit. Can we rely on read length that ReadFile
returns? Doing (ret && size && !*read_len) -> EOF. Depending on how 0
reads work, when EOF is already reached.